[PATCH] ext4: initial copy of files from ext3

Start of the ext4 patch series.  See Documentation/filesystems/ext4.txt for
details.

This is a simple copy of the files in fs/ext3 to fs/ext4 and
/usr/incude/linux/ext3* to /usr/include/ex4*
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/ext4/Makefile

+#
+# Makefile for the linux ext3-filesystem routines.
+#
+
+obj-$(CONFIG_EXT3_FS) += ext3.o
+
+ext3-y	:= balloc.o bitmap.o dir.o file.o fsync.o ialloc.o inode.o \
+	   ioctl.o namei.o super.o symlink.o hash.o resize.o
+
+ext3-$(CONFIG_EXT3_FS_XATTR)	 += xattr.o xattr_user.o xattr_trusted.o
+ext3-$(CONFIG_EXT3_FS_POSIX_ACL) += acl.o
+ext3-$(CONFIG_EXT3_FS_SECURITY)	 += xattr_security.o

fs/ext4/acl.c

+/*
+ * linux/fs/ext3/acl.c
+ *
+ * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
+ */
+
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/capability.h>
+#include <linux/fs.h>
+#include <linux/ext3_jbd.h>
+#include <linux/ext3_fs.h>
+#include "xattr.h"
+#include "acl.h"
+
+/*
+ * Convert from filesystem to in-memory representation.
+ */
+static struct posix_acl *
+ext3_acl_from_disk(const void *value, size_t size)
+{
+	const char *end = (char *)value + size;
+	int n, count;
+	struct posix_acl *acl;
+
+	if (!value)
+		return NULL;
+	if (size < sizeof(ext3_acl_header))
+		 return ERR_PTR(-EINVAL);
+	if (((ext3_acl_header *)value)->a_version !=
+	    cpu_to_le32(EXT3_ACL_VERSION))
+		return ERR_PTR(-EINVAL);
+	value = (char *)value + sizeof(ext3_acl_header);
+	count = ext3_acl_count(size);
+	if (count < 0)
+		return ERR_PTR(-EINVAL);
+	if (count == 0)
+		return NULL;
+	acl = posix_acl_alloc(count, GFP_KERNEL);
+	if (!acl)
+		return ERR_PTR(-ENOMEM);
+	for (n=0; n < count; n++) {
+		ext3_acl_entry *entry =
+			(ext3_acl_entry *)value;
+		if ((char *)value + sizeof(ext3_acl_entry_short) > end)
+			goto fail;
+		acl->a_entries[n].e_tag  = le16_to_cpu(entry->e_tag);
+		acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
+		switch(acl->a_entries[n].e_tag) {
+			case ACL_USER_OBJ:
+			case ACL_GROUP_OBJ:
+			case ACL_MASK:
+			case ACL_OTHER:
+				value = (char *)value +
+					sizeof(ext3_acl_entry_short);
+				acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
+				break;
+
+			case ACL_USER:
+			case ACL_GROUP:
+				value = (char *)value + sizeof(ext3_acl_entry);
+				if ((char *)value > end)
+					goto fail;
+				acl->a_entries[n].e_id =
+					le32_to_cpu(entry->e_id);
+				break;
+
+			default:
+				goto fail;
+		}
+	}
+	if (value != end)
+		goto fail;
+	return acl;
+
+fail:
+	posix_acl_release(acl);
+	return ERR_PTR(-EINVAL);
+}
+
+/*
+ * Convert from in-memory to filesystem representation.
+ */
+static void *
+ext3_acl_to_disk(const struct posix_acl *acl, size_t *size)
+{
+	ext3_acl_header *ext_acl;
+	char *e;
+	size_t n;
+
+	*size = ext3_acl_size(acl->a_count);
+	ext_acl = kmalloc(sizeof(ext3_acl_header) + acl->a_count *
+			sizeof(ext3_acl_entry), GFP_KERNEL);
+	if (!ext_acl)
+		return ERR_PTR(-ENOMEM);
+	ext_acl->a_version = cpu_to_le32(EXT3_ACL_VERSION);
+	e = (char *)ext_acl + sizeof(ext3_acl_header);
+	for (n=0; n < acl->a_count; n++) {
+		ext3_acl_entry *entry = (ext3_acl_entry *)e;
+		entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
+		entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
+		switch(acl->a_entries[n].e_tag) {
+			case ACL_USER:
+			case ACL_GROUP:
+				entry->e_id =
+					cpu_to_le32(acl->a_entries[n].e_id);
+				e += sizeof(ext3_acl_entry);
+				break;
+
+			case ACL_USER_OBJ:
+			case ACL_GROUP_OBJ:
+			case ACL_MASK:
+			case ACL_OTHER:
+				e += sizeof(ext3_acl_entry_short);
+				break;
+
+			default:
+				goto fail;
+		}
+	}
+	return (char *)ext_acl;
+
+fail:
+	kfree(ext_acl);
+	return ERR_PTR(-EINVAL);
+}
+
+static inline struct posix_acl *
+ext3_iget_acl(struct inode *inode, struct posix_acl **i_acl)
+{
+	struct posix_acl *acl = EXT3_ACL_NOT_CACHED;
+
+	spin_lock(&inode->i_lock);
+	if (*i_acl != EXT3_ACL_NOT_CACHED)
+		acl = posix_acl_dup(*i_acl);
+	spin_unlock(&inode->i_lock);
+
+	return acl;
+}
+
+static inline void
+ext3_iset_acl(struct inode *inode, struct posix_acl **i_acl,
+                  struct posix_acl *acl)
+{
+	spin_lock(&inode->i_lock);
+	if (*i_acl != EXT3_ACL_NOT_CACHED)
+		posix_acl_release(*i_acl);
+	*i_acl = posix_acl_dup(acl);
+	spin_unlock(&inode->i_lock);
+}
+
+/*
+ * Inode operation get_posix_acl().
+ *
+ * inode->i_mutex: don't care
+ */
+static struct posix_acl *
+ext3_get_acl(struct inode *inode, int type)
+{
+	struct ext3_inode_info *ei = EXT3_I(inode);
+	int name_index;
+	char *value = NULL;
+	struct posix_acl *acl;
+	int retval;
+
+	if (!test_opt(inode->i_sb, POSIX_ACL))
+		return NULL;
+
+	switch(type) {
+		case ACL_TYPE_ACCESS:
+			acl = ext3_iget_acl(inode, &ei->i_acl);
+			if (acl != EXT3_ACL_NOT_CACHED)
+				return acl;
+			name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
+			break;
+
+		case ACL_TYPE_DEFAULT:
+			acl = ext3_iget_acl(inode, &ei->i_default_acl);
+			if (acl != EXT3_ACL_NOT_CACHED)
+				return acl;
+			name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
+			break;
+
+		default:
+			return ERR_PTR(-EINVAL);
+	}
+	retval = ext3_xattr_get(inode, name_index, "", NULL, 0);
+	if (retval > 0) {
+		value = kmalloc(retval, GFP_KERNEL);
+		if (!value)
+			return ERR_PTR(-ENOMEM);
+		retval = ext3_xattr_get(inode, name_index, "", value, retval);
+	}
+	if (retval > 0)
+		acl = ext3_acl_from_disk(value, retval);
+	else if (retval == -ENODATA || retval == -ENOSYS)
+		acl = NULL;
+	else
+		acl = ERR_PTR(retval);
+	kfree(value);
+
+	if (!IS_ERR(acl)) {
+		switch(type) {
+			case ACL_TYPE_ACCESS:
+				ext3_iset_acl(inode, &ei->i_acl, acl);
+				break;
+
+			case ACL_TYPE_DEFAULT:
+				ext3_iset_acl(inode, &ei->i_default_acl, acl);
+				break;
+		}
+	}
+	return acl;
+}
+
+/*
+ * Set the access or default ACL of an inode.
+ *
+ * inode->i_mutex: down unless called from ext3_new_inode
+ */
+static int
+ext3_set_acl(handle_t *handle, struct inode *inode, int type,
+	     struct posix_acl *acl)
+{
+	struct ext3_inode_info *ei = EXT3_I(inode);
+	int name_index;
+	void *value = NULL;
+	size_t size = 0;
+	int error;
+
+	if (S_ISLNK(inode->i_mode))
+		return -EOPNOTSUPP;
+
+	switch(type) {
+		case ACL_TYPE_ACCESS:
+			name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS;
+			if (acl) {
+				mode_t mode = inode->i_mode;
+				error = posix_acl_equiv_mode(acl, &mode);
+				if (error < 0)
+					return error;
+				else {
+					inode->i_mode = mode;
+					ext3_mark_inode_dirty(handle, inode);
+					if (error == 0)
+						acl = NULL;
+				}
+			}
+			break;
+
+		case ACL_TYPE_DEFAULT:
+			name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT;
+			if (!S_ISDIR(inode->i_mode))
+				return acl ? -EACCES : 0;
+			break;
+
+		default:
+			return -EINVAL;
+	}
+	if (acl) {
+		value = ext3_acl_to_disk(acl, &size);
+		if (IS_ERR(value))
+			return (int)PTR_ERR(value);
+	}
+
+	error = ext3_xattr_set_handle(handle, inode, name_index, "",
+				      value, size, 0);
+
+	kfree(value);
+	if (!error) {
+		switch(type) {
+			case ACL_TYPE_ACCESS:
+				ext3_iset_acl(inode, &ei->i_acl, acl);
+				break;
+
+			case ACL_TYPE_DEFAULT:
+				ext3_iset_acl(inode, &ei->i_default_acl, acl);
+				break;
+		}
+	}
+	return error;
+}
+
+static int
+ext3_check_acl(struct inode *inode, int mask)
+{
+	struct posix_acl *acl = ext3_get_acl(inode, ACL_TYPE_ACCESS);
+
+	if (IS_ERR(acl))
+		return PTR_ERR(acl);
+	if (acl) {
+		int error = posix_acl_permission(inode, acl, mask);
+		posix_acl_release(acl);
+		return error;
+	}
+
+	return -EAGAIN;
+}
+
+int
+ext3_permission(struct inode *inode, int mask, struct nameidata *nd)
+{
+	return generic_permission(inode, mask, ext3_check_acl);
+}
+
+/*
+ * Initialize the ACLs of a new inode. Called from ext3_new_inode.
+ *
+ * dir->i_mutex: down
+ * inode->i_mutex: up (access to inode is still exclusive)
+ */
+int
+ext3_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
+{
+	struct posix_acl *acl = NULL;
+	int error = 0;
+
+	if (!S_ISLNK(inode->i_mode)) {
+		if (test_opt(dir->i_sb, POSIX_ACL)) {
+			acl = ext3_get_acl(dir, ACL_TYPE_DEFAULT);
+			if (IS_ERR(acl))
+				return PTR_ERR(acl);
+		}
+		if (!acl)
+			inode->i_mode &= ~current->fs->umask;
+	}
+	if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
+		struct posix_acl *clone;
+		mode_t mode;
+
+		if (S_ISDIR(inode->i_mode)) {
+			error = ext3_set_acl(handle, inode,
+					     ACL_TYPE_DEFAULT, acl);
+			if (error)
+				goto cleanup;
+		}
+		clone = posix_acl_clone(acl, GFP_KERNEL);
+		error = -ENOMEM;
+		if (!clone)
+			goto cleanup;
+
+		mode = inode->i_mode;
+		error = posix_acl_create_masq(clone, &mode);
+		if (error >= 0) {
+			inode->i_mode = mode;
+			if (error > 0) {
+				/* This is an extended ACL */
+				error = ext3_set_acl(handle, inode,
+						     ACL_TYPE_ACCESS, clone);
+			}
+		}
+		posix_acl_release(clone);
+	}
+cleanup:
+	posix_acl_release(acl);
+	return error;
+}
+
+/*
+ * Does chmod for an inode that may have an Access Control List. The
+ * inode->i_mode field must be updated to the desired value by the caller
+ * before calling this function.
+ * Returns 0 on success, or a negative error number.
+ *
+ * We change the ACL rather than storing some ACL entries in the file
+ * mode permission bits (which would be more efficient), because that
+ * would break once additional permissions (like  ACL_APPEND, ACL_DELETE
+ * for directories) are added. There are no more bits available in the
+ * file mode.
+ *
+ * inode->i_mutex: down
+ */
+int
+ext3_acl_chmod(struct inode *inode)
+{
+	struct posix_acl *acl, *clone;
+        int error;
+
+	if (S_ISLNK(inode->i_mode))
+		return -EOPNOTSUPP;
+	if (!test_opt(inode->i_sb, POSIX_ACL))
+		return 0;
+	acl = ext3_get_acl(inode, ACL_TYPE_ACCESS);
+	if (IS_ERR(acl) || !acl)
+		return PTR_ERR(acl);
+	clone = posix_acl_clone(acl, GFP_KERNEL);
+	posix_acl_release(acl);
+	if (!clone)
+		return -ENOMEM;
+	error = posix_acl_chmod_masq(clone, inode->i_mode);
+	if (!error) {
+		handle_t *handle;
+		int retries = 0;
+
+	retry:
+		handle = ext3_journal_start(inode,
+				EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
+		if (IS_ERR(handle)) {
+			error = PTR_ERR(handle);
+			ext3_std_error(inode->i_sb, error);
+			goto out;
+		}
+		error = ext3_set_acl(handle, inode, ACL_TYPE_ACCESS, clone);
+		ext3_journal_stop(handle);
+		if (error == -ENOSPC &&
+		    ext3_should_retry_alloc(inode->i_sb, &retries))
+			goto retry;
+	}
+out:
+	posix_acl_release(clone);
+	return error;
+}
+
+/*
+ * Extended attribute handlers
+ */
+static size_t
+ext3_xattr_list_acl_access(struct inode *inode, char *list, size_t list_len,
+			   const char *name, size_t name_len)
+{
+	const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
+
+	if (!test_opt(inode->i_sb, POSIX_ACL))
+		return 0;
+	if (list && size <= list_len)
+		memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
+	return size;
+}
+
+static size_t
+ext3_xattr_list_acl_default(struct inode *inode, char *list, size_t list_len,
+			    const char *name, size_t name_len)
+{
+	const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
+
+	if (!test_opt(inode->i_sb, POSIX_ACL))
+		return 0;
+	if (list && size <= list_len)
+		memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
+	return size;
+}
+
+static int
+ext3_xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size)
+{
+	struct posix_acl *acl;
+	int error;
+
+	if (!test_opt(inode->i_sb, POSIX_ACL))
+		return -EOPNOTSUPP;
+
+	acl = ext3_get_acl(inode, type);
+	if (IS_ERR(acl))
+		return PTR_ERR(acl);
+	if (acl == NULL)
+		return -ENODATA;
+	error = posix_acl_to_xattr(acl, buffer, size);
+	posix_acl_release(acl);
+
+	return error;
+}
+
+static int
+ext3_xattr_get_acl_access(struct inode *inode, const char *name,
+			  void *buffer, size_t size)
+{
+	if (strcmp(name, "") != 0)
+		return -EINVAL;
+	return ext3_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size);
+}
+
+static int
+ext3_xattr_get_acl_default(struct inode *inode, const char *name,
+			   void *buffer, size_t size)
+{
+	if (strcmp(name, "") != 0)
+		return -EINVAL;
+	return ext3_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size);
+}
+
+static int
+ext3_xattr_set_acl(struct inode *inode, int type, const void *value,
+		   size_t size)
+{
+	handle_t *handle;
+	struct posix_acl *acl;
+	int error, retries = 0;
+
+	if (!test_opt(inode->i_sb, POSIX_ACL))
+		return -EOPNOTSUPP;
+	if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
+		return -EPERM;
+
+	if (value) {
+		acl = posix_acl_from_xattr(value, size);
+		if (IS_ERR(acl))
+			return PTR_ERR(acl);
+		else if (acl) {
+			error = posix_acl_valid(acl);
+			if (error)
+				goto release_and_out;
+		}
+	} else
+		acl = NULL;
+
+retry:
+	handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	error = ext3_set_acl(handle, inode, type, acl);
+	ext3_journal_stop(handle);
+	if (error == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
+		goto retry;
+
+release_and_out:
+	posix_acl_release(acl);
+	return error;
+}
+
+static int
+ext3_xattr_set_acl_access(struct inode *inode, const char *name,
+			  const void *value, size_t size, int flags)
+{
+	if (strcmp(name, "") != 0)
+		return -EINVAL;
+	return ext3_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size);
+}
+
+static int
+ext3_xattr_set_acl_default(struct inode *inode, const char *name,
+			   const void *value, size_t size, int flags)
+{
+	if (strcmp(name, "") != 0)
+		return -EINVAL;
+	return ext3_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size);
+}
+
+struct xattr_handler ext3_xattr_acl_access_handler = {
+	.prefix	= POSIX_ACL_XATTR_ACCESS,
+	.list	= ext3_xattr_list_acl_access,
+	.get	= ext3_xattr_get_acl_access,
+	.set	= ext3_xattr_set_acl_access,
+};
+
+struct xattr_handler ext3_xattr_acl_default_handler = {
+	.prefix	= POSIX_ACL_XATTR_DEFAULT,
+	.list	= ext3_xattr_list_acl_default,
+	.get	= ext3_xattr_get_acl_default,
+	.set	= ext3_xattr_set_acl_default,
+};

fs/ext4/acl.h

+/*
+  File: fs/ext3/acl.h
+
+  (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
+*/
+
+#include <linux/posix_acl_xattr.h>
+
+#define EXT3_ACL_VERSION	0x0001
+
+typedef struct {
+	__le16		e_tag;
+	__le16		e_perm;
+	__le32		e_id;
+} ext3_acl_entry;
+
+typedef struct {
+	__le16		e_tag;
+	__le16		e_perm;
+} ext3_acl_entry_short;
+
+typedef struct {
+	__le32		a_version;
+} ext3_acl_header;
+
+static inline size_t ext3_acl_size(int count)
+{
+	if (count <= 4) {
+		return sizeof(ext3_acl_header) +
+		       count * sizeof(ext3_acl_entry_short);
+	} else {
+		return sizeof(ext3_acl_header) +
+		       4 * sizeof(ext3_acl_entry_short) +
+		       (count - 4) * sizeof(ext3_acl_entry);
+	}
+}
+
+static inline int ext3_acl_count(size_t size)
+{
+	ssize_t s;
+	size -= sizeof(ext3_acl_header);
+	s = size - 4 * sizeof(ext3_acl_entry_short);
+	if (s < 0) {
+		if (size % sizeof(ext3_acl_entry_short))
+			return -1;
+		return size / sizeof(ext3_acl_entry_short);
+	} else {
+		if (s % sizeof(ext3_acl_entry))
+			return -1;
+		return s / sizeof(ext3_acl_entry) + 4;
+	}
+}
+
+#ifdef CONFIG_EXT3_FS_POSIX_ACL
+
+/* Value for inode->u.ext3_i.i_acl and inode->u.ext3_i.i_default_acl
+   if the ACL has not been cached */
+#define EXT3_ACL_NOT_CACHED ((void *)-1)
+
+/* acl.c */
+extern int ext3_permission (struct inode *, int, struct nameidata *);
+extern int ext3_acl_chmod (struct inode *);
+extern int ext3_init_acl (handle_t *, struct inode *, struct inode *);
+
+#else  /* CONFIG_EXT3_FS_POSIX_ACL */
+#include <linux/sched.h>
+#define ext3_permission NULL
+
+static inline int
+ext3_acl_chmod(struct inode *inode)
+{
+	return 0;
+}
+
+static inline int
+ext3_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
+{
+	return 0;
+}
+#endif  /* CONFIG_EXT3_FS_POSIX_ACL */
+

fs/ext4/balloc.c

+/*
+ *  linux/fs/ext3/balloc.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ */
+
+#include <linux/time.h>
+#include <linux/capability.h>
+#include <linux/fs.h>
+#include <linux/jbd.h>
+#include <linux/ext3_fs.h>
+#include <linux/ext3_jbd.h>
+#include <linux/quotaops.h>
+#include <linux/buffer_head.h>
+
+/*
+ * balloc.c contains the blocks allocation and deallocation routines
+ */
+
+/*
+ * The free blocks are managed by bitmaps.  A file system contains several
+ * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
+ * block for inodes, N blocks for the inode table and data blocks.
+ *
+ * The file system contains group descriptors which are located after the
+ * super block.  Each descriptor contains the number of the bitmap block and
+ * the free blocks count in the block.  The descriptors are loaded in memory
+ * when a file system is mounted (see ext3_read_super).
+ */
+
+
+#define in_range(b, first, len)	((b) >= (first) && (b) <= (first) + (len) - 1)
+
+/**
+ * ext3_get_group_desc() -- load group descriptor from disk
+ * @sb:			super block
+ * @block_group:	given block group
+ * @bh:			pointer to the buffer head to store the block
+ *			group descriptor
+ */
+struct ext3_group_desc * ext3_get_group_desc(struct super_block * sb,
+					     unsigned int block_group,
+					     struct buffer_head ** bh)
+{
+	unsigned long group_desc;
+	unsigned long offset;
+	struct ext3_group_desc * desc;
+	struct ext3_sb_info *sbi = EXT3_SB(sb);
+
+	if (block_group >= sbi->s_groups_count) {
+		ext3_error (sb, "ext3_get_group_desc",
+			    "block_group >= groups_count - "
+			    "block_group = %d, groups_count = %lu",
+			    block_group, sbi->s_groups_count);
+
+		return NULL;
+	}
+	smp_rmb();
+
+	group_desc = block_group >> EXT3_DESC_PER_BLOCK_BITS(sb);
+	offset = block_group & (EXT3_DESC_PER_BLOCK(sb) - 1);
+	if (!sbi->s_group_desc[group_desc]) {
+		ext3_error (sb, "ext3_get_group_desc",
+			    "Group descriptor not loaded - "
+			    "block_group = %d, group_desc = %lu, desc = %lu",
+			     block_group, group_desc, offset);
+		return NULL;
+	}
+
+	desc = (struct ext3_group_desc *) sbi->s_group_desc[group_desc]->b_data;
+	if (bh)
+		*bh = sbi->s_group_desc[group_desc];
+	return desc + offset;
+}
+
+/**
+ * read_block_bitmap()
+ * @sb:			super block
+ * @block_group:	given block group
+ *
+ * Read the bitmap for a given block_group, reading into the specified
+ * slot in the superblock's bitmap cache.
+ *
+ * Return buffer_head on success or NULL in case of failure.
+ */
+static struct buffer_head *
+read_block_bitmap(struct super_block *sb, unsigned int block_group)
+{
+	struct ext3_group_desc * desc;
+	struct buffer_head * bh = NULL;
+
+	desc = ext3_get_group_desc (sb, block_group, NULL);
+	if (!desc)
+		goto error_out;
+	bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap));
+	if (!bh)
+		ext3_error (sb, "read_block_bitmap",
+			    "Cannot read block bitmap - "
+			    "block_group = %d, block_bitmap = %u",
+			    block_group, le32_to_cpu(desc->bg_block_bitmap));
+error_out:
+	return bh;
+}
+/*
+ * The reservation window structure operations
+ * --------------------------------------------
+ * Operations include:
+ * dump, find, add, remove, is_empty, find_next_reservable_window, etc.
+ *
+ * We use a red-black tree to represent per-filesystem reservation
+ * windows.
+ *
+ */
+
+/**
+ * __rsv_window_dump() -- Dump the filesystem block allocation reservation map
+ * @rb_root:		root of per-filesystem reservation rb tree
+ * @verbose:		verbose mode
+ * @fn:			function which wishes to dump the reservation map
+ *
+ * If verbose is turned on, it will print the whole block reservation
+ * windows(start, end).	Otherwise, it will only print out the "bad" windows,
+ * those windows that overlap with their immediate neighbors.
+ */
+#if 1
+static void __rsv_window_dump(struct rb_root *root, int verbose,
+			      const char *fn)
+{
+	struct rb_node *n;
+	struct ext3_reserve_window_node *rsv, *prev;
+	int bad;
+
+restart:
+	n = rb_first(root);
+	bad = 0;
+	prev = NULL;
+
+	printk("Block Allocation Reservation Windows Map (%s):\n", fn);
+	while (n) {
+		rsv = list_entry(n, struct ext3_reserve_window_node, rsv_node);
+		if (verbose)
+			printk("reservation window 0x%p "
+			       "start:  %lu, end:  %lu\n",
+			       rsv, rsv->rsv_start, rsv->rsv_end);
+		if (rsv->rsv_start && rsv->rsv_start >= rsv->rsv_end) {
+			printk("Bad reservation %p (start >= end)\n",
+			       rsv);
+			bad = 1;
+		}
+		if (prev && prev->rsv_end >= rsv->rsv_start) {
+			printk("Bad reservation %p (prev->end >= start)\n",
+			       rsv);
+			bad = 1;
+		}
+		if (bad) {
+			if (!verbose) {
+				printk("Restarting reservation walk in verbose mode\n");
+				verbose = 1;
+				goto restart;
+			}
+		}
+		n = rb_next(n);
+		prev = rsv;
+	}
+	printk("Window map complete.\n");
+	if (bad)
+		BUG();
+}
+#define rsv_window_dump(root, verbose) \
+	__rsv_window_dump((root), (verbose), __FUNCTION__)
+#else
+#define rsv_window_dump(root, verbose) do {} while (0)
+#endif
+
+/**
+ * goal_in_my_reservation()
+ * @rsv:		inode's reservation window
+ * @grp_goal:		given goal block relative to the allocation block group
+ * @group:		the current allocation block group
+ * @sb:			filesystem super block
+ *
+ * Test if the given goal block (group relative) is within the file's
+ * own block reservation window range.
+ *
+ * If the reservation window is outside the goal allocation group, return 0;
+ * grp_goal (given goal block) could be -1, which means no specific
+ * goal block. In this case, always return 1.
+ * If the goal block is within the reservation window, return 1;
+ * otherwise, return 0;
+ */
+static int
+goal_in_my_reservation(struct ext3_reserve_window *rsv, ext3_grpblk_t grp_goal,
+			unsigned int group, struct super_block * sb)
+{
+	ext3_fsblk_t group_first_block, group_last_block;
+
+	group_first_block = ext3_group_first_block_no(sb, group);
+	group_last_block = group_first_block + (EXT3_BLOCKS_PER_GROUP(sb) - 1);
+
+	if ((rsv->_rsv_start > group_last_block) ||
+	    (rsv->_rsv_end < group_first_block))
+		return 0;
+	if ((grp_goal >= 0) && ((grp_goal + group_first_block < rsv->_rsv_start)
+		|| (grp_goal + group_first_block > rsv->_rsv_end)))
+		return 0;
+	return 1;
+}
+
+/**
+ * search_reserve_window()
+ * @rb_root:		root of reservation tree
+ * @goal:		target allocation block
+ *
+ * Find the reserved window which includes the goal, or the previous one
+ * if the goal is not in any window.
+ * Returns NULL if there are no windows or if all windows start after the goal.
+ */
+static struct ext3_reserve_window_node *
+search_reserve_window(struct rb_root *root, ext3_fsblk_t goal)
+{
+	struct rb_node *n = root->rb_node;
+	struct ext3_reserve_window_node *rsv;
+
+	if (!n)
+		return NULL;
+
+	do {
+		rsv = rb_entry(n, struct ext3_reserve_window_node, rsv_node);
+
+		if (goal < rsv->rsv_start)
+			n = n->rb_left;
+		else if (goal > rsv->rsv_end)
+			n = n->rb_right;
+		else
+			return rsv;
+	} while (n);
+	/*
+	 * We've fallen off the end of the tree: the goal wasn't inside
+	 * any particular node.  OK, the previous node must be to one
+	 * side of the interval containing the goal.  If it's the RHS,
+	 * we need to back up one.
+	 */
+	if (rsv->rsv_start > goal) {
+		n = rb_prev(&rsv->rsv_node);
+		rsv = rb_entry(n, struct ext3_reserve_window_node, rsv_node);
+	}
+	return rsv;
+}
+
+/**
+ * ext3_rsv_window_add() -- Insert a window to the block reservation rb tree.
+ * @sb:			super block
+ * @rsv:		reservation window to add
+ *
+ * Must be called with rsv_lock hold.
+ */
+void ext3_rsv_window_add(struct super_block *sb,
+		    struct ext3_reserve_window_node *rsv)
+{
+	struct rb_root *root = &EXT3_SB(sb)->s_rsv_window_root;
+	struct rb_node *node = &rsv->rsv_node;
+	ext3_fsblk_t start = rsv->rsv_start;
+
+	struct rb_node ** p = &root->rb_node;
+	struct rb_node * parent = NULL;
+	struct ext3_reserve_window_node *this;
+
+	while (*p)
+	{
+		parent = *p;
+		this = rb_entry(parent, struct ext3_reserve_window_node, rsv_node);
+
+		if (start < this->rsv_start)
+			p = &(*p)->rb_left;
+		else if (start > this->rsv_end)
+			p = &(*p)->rb_right;
+		else {
+			rsv_window_dump(root, 1);
+			BUG();
+		}
+	}
+
+	rb_link_node(node, parent, p);
+	rb_insert_color(node, root);
+}
+
+/**
+ * ext3_rsv_window_remove() -- unlink a window from the reservation rb tree
+ * @sb:			super block
+ * @rsv:		reservation window to remove
+ *
+ * Mark the block reservation window as not allocated, and unlink it
+ * from the filesystem reservation window rb tree. Must be called with
+ * rsv_lock hold.
+ */
+static void rsv_window_remove(struct super_block *sb,
+			      struct ext3_reserve_window_node *rsv)
+{
+	rsv->rsv_start = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
+	rsv->rsv_end = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
+	rsv->rsv_alloc_hit = 0;
+	rb_erase(&rsv->rsv_node, &EXT3_SB(sb)->s_rsv_window_root);
+}
+
+/*
+ * rsv_is_empty() -- Check if the reservation window is allocated.
+ * @rsv:		given reservation window to check
+ *
+ * returns 1 if the end block is EXT3_RESERVE_WINDOW_NOT_ALLOCATED.
+ */
+static inline int rsv_is_empty(struct ext3_reserve_window *rsv)
+{
+	/* a valid reservation end block could not be 0 */
+	return rsv->_rsv_end == EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
+}
+
+/**
+ * ext3_init_block_alloc_info()
+ * @inode:		file inode structure
+ *
+ * Allocate and initialize the	reservation window structure, and
+ * link the window to the ext3 inode structure at last
+ *
+ * The reservation window structure is only dynamically allocated
+ * and linked to ext3 inode the first time the open file
+ * needs a new block. So, before every ext3_new_block(s) call, for
+ * regular files, we should check whether the reservation window
+ * structure exists or not. In the latter case, this function is called.
+ * Fail to do so will result in block reservation being turned off for that
+ * open file.
+ *
+ * This function is called from ext3_get_blocks_handle(), also called
+ * when setting the reservation window size through ioctl before the file
+ * is open for write (needs block allocation).
+ *
+ * Needs truncate_mutex protection prior to call this function.
+ */
+void ext3_init_block_alloc_info(struct inode *inode)
+{
+	struct ext3_inode_info *ei = EXT3_I(inode);
+	struct ext3_block_alloc_info *block_i = ei->i_block_alloc_info;
+	struct super_block *sb = inode->i_sb;
+
+	block_i = kmalloc(sizeof(*block_i), GFP_NOFS);
+	if (block_i) {
+		struct ext3_reserve_window_node *rsv = &block_i->rsv_window_node;
+
+		rsv->rsv_start = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
+		rsv->rsv_end = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
+
+		/*
+		 * if filesystem is mounted with NORESERVATION, the goal
+		 * reservation window size is set to zero to indicate
+		 * block reservation is off
+		 */
+		if (!test_opt(sb, RESERVATION))
+			rsv->rsv_goal_size = 0;
+		else
+			rsv->rsv_goal_size = EXT3_DEFAULT_RESERVE_BLOCKS;
+		rsv->rsv_alloc_hit = 0;
+		block_i->last_alloc_logical_block = 0;
+		block_i->last_alloc_physical_block = 0;
+	}
+	ei->i_block_alloc_info = block_i;
+}
+
+/**
+ * ext3_discard_reservation()
+ * @inode:		inode
+ *
+ * Discard(free) block reservation window on last file close, or truncate
+ * or at last iput().
+ *
+ * It is being called in three cases:
+ *	ext3_release_file(): last writer close the file
+ *	ext3_clear_inode(): last iput(), when nobody link to this file.
+ *	ext3_truncate(): when the block indirect map is about to change.
+ *
+ */
+void ext3_discard_reservation(struct inode *inode)
+{
+	struct ext3_inode_info *ei = EXT3_I(inode);
+	struct ext3_block_alloc_info *block_i = ei->i_block_alloc_info;
+	struct ext3_reserve_window_node *rsv;
+	spinlock_t *rsv_lock = &EXT3_SB(inode->i_sb)->s_rsv_window_lock;
+
+	if (!block_i)
+		return;
+
+	rsv = &block_i->rsv_window_node;
+	if (!rsv_is_empty(&rsv->rsv_window)) {
+		spin_lock(rsv_lock);
+		if (!rsv_is_empty(&rsv->rsv_window))
+			rsv_window_remove(inode->i_sb, rsv);
+		spin_unlock(rsv_lock);
+	}
+}
+
+/**
+ * ext3_free_blocks_sb() -- Free given blocks and update quota
+ * @handle:			handle to this transaction
+ * @sb:				super block
+ * @block:			start physcial block to free
+ * @count:			number of blocks to free
+ * @pdquot_freed_blocks:	pointer to quota
+ */
+void ext3_free_blocks_sb(handle_t *handle, struct super_block *sb,
+			 ext3_fsblk_t block, unsigned long count,
+			 unsigned long *pdquot_freed_blocks)
+{
+	struct buffer_head *bitmap_bh = NULL;
+	struct buffer_head *gd_bh;
+	unsigned long block_group;
+	ext3_grpblk_t bit;
+	unsigned long i;
+	unsigned long overflow;
+	struct ext3_group_desc * desc;
+	struct ext3_super_block * es;
+	struct ext3_sb_info *sbi;
+	int err = 0, ret;
+	ext3_grpblk_t group_freed;
+
+	*pdquot_freed_blocks = 0;
+	sbi = EXT3_SB(sb);
+	es = sbi->s_es;
+	if (block < le32_to_cpu(es->s_first_data_block) ||
+	    block + count < block ||
+	    block + count > le32_to_cpu(es->s_blocks_count)) {
+		ext3_error (sb, "ext3_free_blocks",
+			    "Freeing blocks not in datazone - "
+			    "block = "E3FSBLK", count = %lu", block, count);
+		goto error_return;
+	}
+
+	ext3_debug ("freeing block(s) %lu-%lu\n", block, block + count - 1);
+
+do_more:
+	overflow = 0;
+	block_group = (block - le32_to_cpu(es->s_first_data_block)) /
+		      EXT3_BLOCKS_PER_GROUP(sb);
+	bit = (block - le32_to_cpu(es->s_first_data_block)) %
+		      EXT3_BLOCKS_PER_GROUP(sb);
+	/*
+	 * Check to see if we are freeing blocks across a group
+	 * boundary.
+	 */
+	if (bit + count > EXT3_BLOCKS_PER_GROUP(sb)) {
+		overflow = bit + count - EXT3_BLOCKS_PER_GROUP(sb);
+		count -= overflow;
+	}
+	brelse(bitmap_bh);
+	bitmap_bh = read_block_bitmap(sb, block_group);
+	if (!bitmap_bh)
+		goto error_return;
+	desc = ext3_get_group_desc (sb, block_group, &gd_bh);
+	if (!desc)
+		goto error_return;
+
+	if (in_range (le32_to_cpu(desc->bg_block_bitmap), block, count) ||
+	    in_range (le32_to_cpu(desc->bg_inode_bitmap), block, count) ||
+	    in_range (block, le32_to_cpu(desc->bg_inode_table),
+		      sbi->s_itb_per_group) ||
+	    in_range (block + count - 1, le32_to_cpu(desc->bg_inode_table),
+		      sbi->s_itb_per_group))
+		ext3_error (sb, "ext3_free_blocks",
+			    "Freeing blocks in system zones - "
+			    "Block = "E3FSBLK", count = %lu",
+			    block, count);
+
+	/*
+	 * We are about to start releasing blocks in the bitmap,
+	 * so we need undo access.
+	 */
+	/* @@@ check errors */
+	BUFFER_TRACE(bitmap_bh, "getting undo access");
+	err = ext3_journal_get_undo_access(handle, bitmap_bh);
+	if (err)
+		goto error_return;
+
+	/*
+	 * We are about to modify some metadata.  Call the journal APIs
+	 * to unshare ->b_data if a currently-committing transaction is
+	 * using it
+	 */
+	BUFFER_TRACE(gd_bh, "get_write_access");
+	err = ext3_journal_get_write_access(handle, gd_bh);
+	if (err)
+		goto error_return;
+
+	jbd_lock_bh_state(bitmap_bh);
+
+	for (i = 0, group_freed = 0; i < count; i++) {
+		/*
+		 * An HJ special.  This is expensive...
+		 */
+#ifdef CONFIG_JBD_DEBUG
+		jbd_unlock_bh_state(bitmap_bh);
+		{
+			struct buffer_head *debug_bh;
+			debug_bh = sb_find_get_block(sb, block + i);
+			if (debug_bh) {
+				BUFFER_TRACE(debug_bh, "Deleted!");
+				if (!bh2jh(bitmap_bh)->b_committed_data)
+					BUFFER_TRACE(debug_bh,
+						"No commited data in bitmap");
+				BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap");
+				__brelse(debug_bh);
+			}
+		}
+		jbd_lock_bh_state(bitmap_bh);
+#endif
+		if (need_resched()) {
+			jbd_unlock_bh_state(bitmap_bh);
+			cond_resched();
+			jbd_lock_bh_state(bitmap_bh);
+		}
+		/* @@@ This prevents newly-allocated data from being
+		 * freed and then reallocated within the same
+		 * transaction.
+		 *
+		 * Ideally we would want to allow that to happen, but to
+		 * do so requires making journal_forget() capable of
+		 * revoking the queued write of a data block, which
+		 * implies blocking on the journal lock.  *forget()
+		 * cannot block due to truncate races.
+		 *
+		 * Eventually we can fix this by making journal_forget()
+		 * return a status indicating whether or not it was able
+		 * to revoke the buffer.  On successful revoke, it is
+		 * safe not to set the allocation bit in the committed
+		 * bitmap, because we know that there is no outstanding
+		 * activity on the buffer any more and so it is safe to
+		 * reallocate it.
+		 */
+		BUFFER_TRACE(bitmap_bh, "set in b_committed_data");
+		J_ASSERT_BH(bitmap_bh,
+				bh2jh(bitmap_bh)->b_committed_data != NULL);
+		ext3_set_bit_atomic(sb_bgl_lock(sbi, block_group), bit + i,
+				bh2jh(bitmap_bh)->b_committed_data);
+
+		/*
+		 * We clear the bit in the bitmap after setting the committed
+		 * data bit, because this is the reverse order to that which
+		 * the allocator uses.
+		 */
+		BUFFER_TRACE(bitmap_bh, "clear bit");
+		if (!ext3_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
+						bit + i, bitmap_bh->b_data)) {
+			jbd_unlock_bh_state(bitmap_bh);
+			ext3_error(sb, __FUNCTION__,
+				"bit already cleared for block "E3FSBLK,
+				 block + i);
+			jbd_lock_bh_state(bitmap_bh);
+			BUFFER_TRACE(bitmap_bh, "bit already cleared");
+		} else {
+			group_freed++;
+		}
+	}
+	jbd_unlock_bh_state(bitmap_bh);
+
+	spin_lock(sb_bgl_lock(sbi, block_group));
+	desc->bg_free_blocks_count =
+		cpu_to_le16(le16_to_cpu(desc->bg_free_blocks_count) +
+			group_freed);
+	spin_unlock(sb_bgl_lock(sbi, block_group));
+	percpu_counter_mod(&sbi->s_freeblocks_counter, count);
+
+	/* We dirtied the bitmap block */
+	BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
+	err = ext3_journal_dirty_metadata(handle, bitmap_bh);
+
+	/* And the group descriptor block */
+	BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
+	ret = ext3_journal_dirty_metadata(handle, gd_bh);
+	if (!err) err = ret;
+	*pdquot_freed_blocks += group_freed;
+
+	if (overflow && !err) {
+		block += count;
+		count = overflow;
+		goto do_more;
+	}
+	sb->s_dirt = 1;
+error_return:
+	brelse(bitmap_bh);
+	ext3_std_error(sb, err);
+	return;
+}
+
+/**
+ * ext3_free_blocks() -- Free given blocks and update quota
+ * @handle:		handle for this transaction
+ * @inode:		inode
+ * @block:		start physical block to free
+ * @count:		number of blocks to count
+ */
+void ext3_free_blocks(handle_t *handle, struct inode *inode,
+			ext3_fsblk_t block, unsigned long count)
+{
+	struct super_block * sb;
+	unsigned long dquot_freed_blocks;
+
+	sb = inode->i_sb;
+	if (!sb) {
+		printk ("ext3_free_blocks: nonexistent device");
+		return;
+	}
+	ext3_free_blocks_sb(handle, sb, block, count, &dquot_freed_blocks);
+	if (dquot_freed_blocks)
+		DQUOT_FREE_BLOCK(inode, dquot_freed_blocks);
+	return;
+}
+
+/**
+ * ext3_test_allocatable()
+ * @nr:			given allocation block group
+ * @bh:			bufferhead contains the bitmap of the given block group
+ *
+ * For ext3 allocations, we must not reuse any blocks which are
+ * allocated in the bitmap buffer's "last committed data" copy.  This
+ * prevents deletes from freeing up the page for reuse until we have
+ * committed the delete transaction.
+ *
+ * If we didn't do this, then deleting something and reallocating it as
+ * data would allow the old block to be overwritten before the
+ * transaction committed (because we force data to disk before commit).
+ * This would lead to corruption if we crashed between overwriting the
+ * data and committing the delete.
+ *
+ * @@@ We may want to make this allocation behaviour conditional on
+ * data-writes at some point, and disable it for metadata allocations or
+ * sync-data inodes.
+ */
+static int ext3_test_allocatable(ext3_grpblk_t nr, struct buffer_head *bh)
+{
+	int ret;
+	struct journal_head *jh = bh2jh(bh);
+
+	if (ext3_test_bit(nr, bh->b_data))
+		return 0;
+
+	jbd_lock_bh_state(bh);
+	if (!jh->b_committed_data)
+		ret = 1;
+	else
+		ret = !ext3_test_bit(nr, jh->b_committed_data);
+	jbd_unlock_bh_state(bh);
+	return ret;
+}
+
+/**
+ * bitmap_search_next_usable_block()
+ * @start:		the starting block (group relative) of the search
+ * @bh:			bufferhead contains the block group bitmap
+ * @maxblocks:		the ending block (group relative) of the reservation
+ *
+ * The bitmap search --- search forward alternately through the actual
+ * bitmap on disk and the last-committed copy in journal, until we find a
+ * bit free in both bitmaps.
+ */
+static ext3_grpblk_t
+bitmap_search_next_usable_block(ext3_grpblk_t start, struct buffer_head *bh,
+					ext3_grpblk_t maxblocks)
+{
+	ext3_grpblk_t next;
+	struct journal_head *jh = bh2jh(bh);
+
+	while (start < maxblocks) {
+		next = ext3_find_next_zero_bit(bh->b_data, maxblocks, start);
+		if (next >= maxblocks)
+			return -1;
+		if (ext3_test_allocatable(next, bh))
+			return next;
+		jbd_lock_bh_state(bh);
+		if (jh->b_committed_data)
+			start = ext3_find_next_zero_bit(jh->b_committed_data,
+							maxblocks, next);
+		jbd_unlock_bh_state(bh);
+	}
+	return -1;
+}
+
+/**
+ * find_next_usable_block()
+ * @start:		the starting block (group relative) to find next
+ *			allocatable block in bitmap.
+ * @bh:			bufferhead contains the block group bitmap
+ * @maxblocks:		the ending block (group relative) for the search
+ *
+ * Find an allocatable block in a bitmap.  We honor both the bitmap and
+ * its last-committed copy (if that exists), and perform the "most
+ * appropriate allocation" algorithm of looking for a free block near
+ * the initial goal; then for a free byte somewhere in the bitmap; then
+ * for any free bit in the bitmap.
+ */
+static ext3_grpblk_t
+find_next_usable_block(ext3_grpblk_t start, struct buffer_head *bh,
+			ext3_grpblk_t maxblocks)
+{
+	ext3_grpblk_t here, next;
+	char *p, *r;
+
+	if (start > 0) {
+		/*
+		 * The goal was occupied; search forward for a free
+		 * block within the next XX blocks.
+		 *
+		 * end_goal is more or less random, but it has to be
+		 * less than EXT3_BLOCKS_PER_GROUP. Aligning up to the
+		 * next 64-bit boundary is simple..
+		 */
+		ext3_grpblk_t end_goal = (start + 63) & ~63;
+		if (end_goal > maxblocks)
+			end_goal = maxblocks;
+		here = ext3_find_next_zero_bit(bh->b_data, end_goal, start);
+		if (here < end_goal && ext3_test_allocatable(here, bh))
+			return here;
+		ext3_debug("Bit not found near goal\n");
+	}
+
+	here = start;
+	if (here < 0)
+		here = 0;
+
+	p = ((char *)bh->b_data) + (here >> 3);
+	r = memscan(p, 0, (maxblocks - here + 7) >> 3);
+	next = (r - ((char *)bh->b_data)) << 3;
+
+	if (next < maxblocks && next >= start && ext3_test_allocatable(next, bh))
+		return next;
+
+	/*
+	 * The bitmap search --- search forward alternately through the actual
+	 * bitmap and the last-committed copy until we find a bit free in
+	 * both
+	 */
+	here = bitmap_search_next_usable_block(here, bh, maxblocks);
+	return here;
+}
+
+/**
+ * claim_block()
+ * @block:		the free block (group relative) to allocate
+ * @bh:			the bufferhead containts the block group bitmap
+ *
+ * We think we can allocate this block in this bitmap.  Try to set the bit.
+ * If that succeeds then check that nobody has allocated and then freed the
+ * block since we saw that is was not marked in b_committed_data.  If it _was_
+ * allocated and freed then clear the bit in the bitmap again and return
+ * zero (failure).
+ */
+static inline int
+claim_block(spinlock_t *lock, ext3_grpblk_t block, struct buffer_head *bh)
+{
+	struct journal_head *jh = bh2jh(bh);
+	int ret;
+
+	if (ext3_set_bit_atomic(lock, block, bh->b_data))
+		return 0;
+	jbd_lock_bh_state(bh);
+	if (jh->b_committed_data && ext3_test_bit(block,jh->b_committed_data)) {
+		ext3_clear_bit_atomic(lock, block, bh->b_data);
+		ret = 0;
+	} else {
+		ret = 1;
+	}
+	jbd_unlock_bh_state(bh);
+	return ret;
+}
+
+/**
+ * ext3_try_to_allocate()
+ * @sb:			superblock
+ * @handle:		handle to this transaction
+ * @group:		given allocation block group
+ * @bitmap_bh:		bufferhead holds the block bitmap
+ * @grp_goal:		given target block within the group
+ * @count:		target number of blocks to allocate
+ * @my_rsv:		reservation window
+ *
+ * Attempt to allocate blocks within a give range. Set the range of allocation
+ * first, then find the first free bit(s) from the bitmap (within the range),
+ * and at last, allocate the blocks by claiming the found free bit as allocated.
+ *
+ * To set the range of this allocation:
+ *	if there is a reservation window, only try to allocate block(s) from the
+ *	file's own reservation window;
+ *	Otherwise, the allocation range starts from the give goal block, ends at
+ *	the block group's last block.
+ *
+ * If we failed to allocate the desired block then we may end up crossing to a
+ * new bitmap.  In that case we must release write access to the old one via
+ * ext3_journal_release_buffer(), else we'll run out of credits.
+ */
+static ext3_grpblk_t
+ext3_try_to_allocate(struct super_block *sb, handle_t *handle, int group,
+			struct buffer_head *bitmap_bh, ext3_grpblk_t grp_goal,
+			unsigned long *count, struct ext3_reserve_window *my_rsv)
+{
+	ext3_fsblk_t group_first_block;
+	ext3_grpblk_t start, end;
+	unsigned long num = 0;
+
+	/* we do allocation within the reservation window if we have a window */
+	if (my_rsv) {
+		group_first_block = ext3_group_first_block_no(sb, group);
+		if (my_rsv->_rsv_start >= group_first_block)
+			start = my_rsv->_rsv_start - group_first_block;
+		else
+			/* reservation window cross group boundary */
+			start = 0;
+		end = my_rsv->_rsv_end - group_first_block + 1;
+		if (end > EXT3_BLOCKS_PER_GROUP(sb))
+			/* reservation window crosses group boundary */
+			end = EXT3_BLOCKS_PER_GROUP(sb);
+		if ((start <= grp_goal) && (grp_goal < end))
+			start = grp_goal;
+		else
+			grp_goal = -1;
+	} else {
+		if (grp_goal > 0)
+			start = grp_goal;
+		else
+			start = 0;
+		end = EXT3_BLOCKS_PER_GROUP(sb);
+	}
+
+	BUG_ON(start > EXT3_BLOCKS_PER_GROUP(sb));
+
+repeat:
+	if (grp_goal < 0 || !ext3_test_allocatable(grp_goal, bitmap_bh)) {
+		grp_goal = find_next_usable_block(start, bitmap_bh, end);
+		if (grp_goal < 0)
+			goto fail_access;
+		if (!my_rsv) {
+			int i;
+
+			for (i = 0; i < 7 && grp_goal > start &&
+					ext3_test_allocatable(grp_goal - 1,
+								bitmap_bh);
+					i++, grp_goal--)
+				;
+		}
+	}
+	start = grp_goal;
+
+	if (!claim_block(sb_bgl_lock(EXT3_SB(sb), group),
+		grp_goal, bitmap_bh)) {
+		/*
+		 * The block was allocated by another thread, or it was
+		 * allocated and then freed by another thread
+		 */
+		start++;
+		grp_goal++;
+		if (start >= end)
+			goto fail_access;
+		goto repeat;
+	}
+	num++;
+	grp_goal++;
+	while (num < *count && grp_goal < end
+		&& ext3_test_allocatable(grp_goal, bitmap_bh)
+		&& claim_block(sb_bgl_lock(EXT3_SB(sb), group),
+				grp_goal, bitmap_bh)) {
+		num++;
+		grp_goal++;
+	}
+	*count = num;
+	return grp_goal - num;
+fail_access:
+	*count = num;
+	return -1;
+}
+
+/**
+ *	find_next_reservable_window():
+ *		find a reservable space within the given range.
+ *		It does not allocate the reservation window for now:
+ *		alloc_new_reservation() will do the work later.
+ *
+ *	@search_head: the head of the searching list;
+ *		This is not necessarily the list head of the whole filesystem
+ *
+ *		We have both head and start_block to assist the search
+ *		for the reservable space. The list starts from head,
+ *		but we will shift to the place where start_block is,
+ *		then start from there, when looking for a reservable space.
+ *
+ *	@size: the target new reservation window size
+ *
+ *	@group_first_block: the first block we consider to start
+ *			the real search from
+ *
+ *	@last_block:
+ *		the maximum block number that our goal reservable space
+ *		could start from. This is normally the last block in this
+ *		group. The search will end when we found the start of next
+ *		possible reservable space is out of this boundary.
+ *		This could handle the cross boundary reservation window
+ *		request.
+ *
+ *	basically we search from the given range, rather than the whole
+ *	reservation double linked list, (start_block, last_block)
+ *	to find a free region that is of my size and has not
+ *	been reserved.
+ *
+ */
+static int find_next_reservable_window(
+				struct ext3_reserve_window_node *search_head,
+				struct ext3_reserve_window_node *my_rsv,
+				struct super_block * sb,
+				ext3_fsblk_t start_block,
+				ext3_fsblk_t last_block)
+{
+	struct rb_node *next;
+	struct ext3_reserve_window_node *rsv, *prev;
+	ext3_fsblk_t cur;
+	int size = my_rsv->rsv_goal_size;
+
+	/* TODO: make the start of the reservation window byte-aligned */
+	/* cur = *start_block & ~7;*/
+	cur = start_block;
+	rsv = search_head;
+	if (!rsv)
+		return -1;
+
+	while (1) {
+		if (cur <= rsv->rsv_end)
+			cur = rsv->rsv_end + 1;
+
+		/* TODO?
+		 * in the case we could not find a reservable space
+		 * that is what is expected, during the re-search, we could
+		 * remember what's the largest reservable space we could have
+		 * and return that one.
+		 *
+		 * For now it will fail if we could not find the reservable
+		 * space with expected-size (or more)...
+		 */
+		if (cur > last_block)
+			return -1;		/* fail */
+
+		prev = rsv;
+		next = rb_next(&rsv->rsv_node);
+		rsv = list_entry(next,struct ext3_reserve_window_node,rsv_node);
+
+		/*
+		 * Reached the last reservation, we can just append to the
+		 * previous one.
+		 */
+		if (!next)
+			break;
+
+		if (cur + size <= rsv->rsv_start) {
+			/*
+			 * Found a reserveable space big enough.  We could
+			 * have a reservation across the group boundary here
+			 */
+			break;
+		}
+	}
+	/*
+	 * we come here either :
+	 * when we reach the end of the whole list,
+	 * and there is empty reservable space after last entry in the list.
+	 * append it to the end of the list.
+	 *
+	 * or we found one reservable space in the middle of the list,
+	 * return the reservation window that we could append to.
+	 * succeed.
+	 */
+
+	if ((prev != my_rsv) && (!rsv_is_empty(&my_rsv->rsv_window)))
+		rsv_window_remove(sb, my_rsv);
+
+	/*
+	 * Let's book the whole avaliable window for now.  We will check the
+	 * disk bitmap later and then, if there are free blocks then we adjust
+	 * the window size if it's larger than requested.
+	 * Otherwise, we will remove this node from the tree next time
+	 * call find_next_reservable_window.
+	 */
+	my_rsv->rsv_start = cur;
+	my_rsv->rsv_end = cur + size - 1;
+	my_rsv->rsv_alloc_hit = 0;
+
+	if (prev != my_rsv)
+		ext3_rsv_window_add(sb, my_rsv);
+
+	return 0;
+}
+
+/**
+ *	alloc_new_reservation()--allocate a new reservation window
+ *
+ *		To make a new reservation, we search part of the filesystem
+ *		reservation list (the list that inside the group). We try to
+ *		allocate a new reservation window near the allocation goal,
+ *		or the beginning of the group, if there is no goal.
+ *
+ *		We first find a reservable space after the goal, then from
+ *		there, we check the bitmap for the first free block after
+ *		it. If there is no free block until the end of group, then the
+ *		whole group is full, we failed. Otherwise, check if the free
+ *		block is inside the expected reservable space, if so, we
+ *		succeed.
+ *		If the first free block is outside the reservable space, then
+ *		start from the first free block, we search for next available
+ *		space, and go on.
+ *
+ *	on succeed, a new reservation will be found and inserted into the list
+ *	It contains at least one free block, and it does not overlap with other
+ *	reservation windows.
+ *
+ *	failed: we failed to find a reservation window in this group
+ *
+ *	@rsv: the reservation
+ *
+ *	@grp_goal: The goal (group-relative).  It is where the search for a
+ *		free reservable space should start from.
+ *		if we have a grp_goal(grp_goal >0 ), then start from there,
+ *		no grp_goal(grp_goal = -1), we start from the first block
+ *		of the group.
+ *
+ *	@sb: the super block
+ *	@group: the group we are trying to allocate in
+ *	@bitmap_bh: the block group block bitmap
+ *
+ */
+static int alloc_new_reservation(struct ext3_reserve_window_node *my_rsv,
+		ext3_grpblk_t grp_goal, struct super_block *sb,
+		unsigned int group, struct buffer_head *bitmap_bh)
+{
+	struct ext3_reserve_window_node *search_head;
+	ext3_fsblk_t group_first_block, group_end_block, start_block;
+	ext3_grpblk_t first_free_block;
+	struct rb_root *fs_rsv_root = &EXT3_SB(sb)->s_rsv_window_root;
+	unsigned long size;
+	int ret;
+	spinlock_t *rsv_lock = &EXT3_SB(sb)->s_rsv_window_lock;
+
+	group_first_block = ext3_group_first_block_no(sb, group);
+	group_end_block = group_first_block + (EXT3_BLOCKS_PER_GROUP(sb) - 1);
+
+	if (grp_goal < 0)
+		start_block = group_first_block;
+	else
+		start_block = grp_goal + group_first_block;
+
+	size = my_rsv->rsv_goal_size;
+
+	if (!rsv_is_empty(&my_rsv->rsv_window)) {
+		/*
+		 * if the old reservation is cross group boundary
+		 * and if the goal is inside the old reservation window,
+		 * we will come here when we just failed to allocate from
+		 * the first part of the window. We still have another part
+		 * that belongs to the next group. In this case, there is no
+		 * point to discard our window and try to allocate a new one
+		 * in this group(which will fail). we should
+		 * keep the reservation window, just simply move on.
+		 *
+		 * Maybe we could shift the start block of the reservation
+		 * window to the first block of next group.
+		 */
+
+		if ((my_rsv->rsv_start <= group_end_block) &&
+				(my_rsv->rsv_end > group_end_block) &&
+				(start_block >= my_rsv->rsv_start))
+			return -1;
+
+		if ((my_rsv->rsv_alloc_hit >
+		     (my_rsv->rsv_end - my_rsv->rsv_start + 1) / 2)) {
+			/*
+			 * if the previously allocation hit ratio is
+			 * greater than 1/2, then we double the size of
+			 * the reservation window the next time,
+			 * otherwise we keep the same size window
+			 */
+			size = size * 2;
+			if (size > EXT3_MAX_RESERVE_BLOCKS)
+				size = EXT3_MAX_RESERVE_BLOCKS;
+			my_rsv->rsv_goal_size= size;
+		}
+	}
+
+	spin_lock(rsv_lock);
+	/*
+	 * shift the search start to the window near the goal block
+	 */
+	search_head = search_reserve_window(fs_rsv_root, start_block);
+
+	/*
+	 * find_next_reservable_window() simply finds a reservable window
+	 * inside the given range(start_block, group_end_block).
+	 *
+	 * To make sure the reservation window has a free bit inside it, we
+	 * need to check the bitmap after we found a reservable window.
+	 */
+retry:
+	ret = find_next_reservable_window(search_head, my_rsv, sb,
+						start_block, group_end_block);
+
+	if (ret == -1) {
+		if (!rsv_is_empty(&my_rsv->rsv_window))
+			rsv_window_remove(sb, my_rsv);
+		spin_unlock(rsv_lock);
+		return -1;
+	}
+
+	/*
+	 * On success, find_next_reservable_window() returns the
+	 * reservation window where there is a reservable space after it.
+	 * Before we reserve this reservable space, we need
+	 * to make sure there is at least a free block inside this region.
+	 *
+	 * searching the first free bit on the block bitmap and copy of
+	 * last committed bitmap alternatively, until we found a allocatable
+	 * block. Search start from the start block of the reservable space
+	 * we just found.
+	 */
+	spin_unlock(rsv_lock);
+	first_free_block = bitmap_search_next_usable_block(
+			my_rsv->rsv_start - group_first_block,
+			bitmap_bh, group_end_block - group_first_block + 1);
+
+	if (first_free_block < 0) {
+		/*
+		 * no free block left on the bitmap, no point
+		 * to reserve the space. return failed.
+		 */
+		spin_lock(rsv_lock);
+		if (!rsv_is_empty(&my_rsv->rsv_window))
+			rsv_window_remove(sb, my_rsv);
+		spin_unlock(rsv_lock);
+		return -1;		/* failed */
+	}
+
+	start_block = first_free_block + group_first_block;
+	/*
+	 * check if the first free block is within the
+	 * free space we just reserved
+	 */
+	if (start_block >= my_rsv->rsv_start && start_block < my_rsv->rsv_end)
+		return 0;		/* success */
+	/*
+	 * if the first free bit we found is out of the reservable space
+	 * continue search for next reservable space,
+	 * start from where the free block is,
+	 * we also shift the list head to where we stopped last time
+	 */
+	search_head = my_rsv;
+	spin_lock(rsv_lock);
+	goto retry;
+}
+
+/**
+ * try_to_extend_reservation()
+ * @my_rsv:		given reservation window
+ * @sb:			super block
+ * @size:		the delta to extend
+ *
+ * Attempt to expand the reservation window large enough to have
+ * required number of free blocks
+ *
+ * Since ext3_try_to_allocate() will always allocate blocks within
+ * the reservation window range, if the window size is too small,
+ * multiple blocks allocation has to stop at the end of the reservation
+ * window. To make this more efficient, given the total number of
+ * blocks needed and the current size of the window, we try to
+ * expand the reservation window size if necessary on a best-effort
+ * basis before ext3_new_blocks() tries to allocate blocks,
+ */
+static void try_to_extend_reservation(struct ext3_reserve_window_node *my_rsv,
+			struct super_block *sb, int size)
+{
+	struct ext3_reserve_window_node *next_rsv;
+	struct rb_node *next;
+	spinlock_t *rsv_lock = &EXT3_SB(sb)->s_rsv_window_lock;
+
+	if (!spin_trylock(rsv_lock))
+		return;
+
+	next = rb_next(&my_rsv->rsv_node);
+
+	if (!next)
+		my_rsv->rsv_end += size;
+	else {
+		next_rsv = list_entry(next, struct ext3_reserve_window_node, rsv_node);
+
+		if ((next_rsv->rsv_start - my_rsv->rsv_end - 1) >= size)
+			my_rsv->rsv_end += size;
+		else
+			my_rsv->rsv_end = next_rsv->rsv_start - 1;
+	}
+	spin_unlock(rsv_lock);
+}
+
+/**
+ * ext3_try_to_allocate_with_rsv()
+ * @sb:			superblock
+ * @handle:		handle to this transaction
+ * @group:		given allocation block group
+ * @bitmap_bh:		bufferhead holds the block bitmap
+ * @grp_goal:		given target block within the group
+ * @count:		target number of blocks to allocate
+ * @my_rsv:		reservation window
+ * @errp:		pointer to store the error code
+ *
+ * This is the main function used to allocate a new block and its reservation
+ * window.
+ *
+ * Each time when a new block allocation is need, first try to allocate from
+ * its own reservation.  If it does not have a reservation window, instead of
+ * looking for a free bit on bitmap first, then look up the reservation list to
+ * see if it is inside somebody else's reservation window, we try to allocate a
+ * reservation window for it starting from the goal first. Then do the block
+ * allocation within the reservation window.
+ *
+ * This will avoid keeping on searching the reservation list again and
+ * again when somebody is looking for a free block (without
+ * reservation), and there are lots of free blocks, but they are all
+ * being reserved.
+ *
+ * We use a red-black tree for the per-filesystem reservation list.
+ *
+ */
+static ext3_grpblk_t
+ext3_try_to_allocate_with_rsv(struct super_block *sb, handle_t *handle,
+			unsigned int group, struct buffer_head *bitmap_bh,
+			ext3_grpblk_t grp_goal,
+			struct ext3_reserve_window_node * my_rsv,
+			unsigned long *count, int *errp)
+{
+	ext3_fsblk_t group_first_block, group_last_block;
+	ext3_grpblk_t ret = 0;
+	int fatal;
+	unsigned long num = *count;
+
+	*errp = 0;
+
+	/*
+	 * Make sure we use undo access for the bitmap, because it is critical
+	 * that we do the frozen_data COW on bitmap buffers in all cases even
+	 * if the buffer is in BJ_Forget state in the committing transaction.
+	 */
+	BUFFER_TRACE(bitmap_bh, "get undo access for new block");
+	fatal = ext3_journal_get_undo_access(handle, bitmap_bh);
+	if (fatal) {
+		*errp = fatal;
+		return -1;
+	}
+
+	/*
+	 * we don't deal with reservation when
+	 * filesystem is mounted without reservation
+	 * or the file is not a regular file
+	 * or last attempt to allocate a block with reservation turned on failed
+	 */
+	if (my_rsv == NULL ) {
+		ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh,
+						grp_goal, count, NULL);
+		goto out;
+	}
+	/*
+	 * grp_goal is a group relative block number (if there is a goal)
+	 * 0 < grp_goal < EXT3_BLOCKS_PER_GROUP(sb)
+	 * first block is a filesystem wide block number
+	 * first block is the block number of the first block in this group
+	 */
+	group_first_block = ext3_group_first_block_no(sb, group);
+	group_last_block = group_first_block + (EXT3_BLOCKS_PER_GROUP(sb) - 1);
+
+	/*
+	 * Basically we will allocate a new block from inode's reservation
+	 * window.
+	 *
+	 * We need to allocate a new reservation window, if:
+	 * a) inode does not have a reservation window; or
+	 * b) last attempt to allocate a block from existing reservation
+	 *    failed; or
+	 * c) we come here with a goal and with a reservation window
+	 *
+	 * We do not need to allocate a new reservation window if we come here
+	 * at the beginning with a goal and the goal is inside the window, or
+	 * we don't have a goal but already have a reservation window.
+	 * then we could go to allocate from the reservation window directly.
+	 */
+	while (1) {
+		if (rsv_is_empty(&my_rsv->rsv_window) || (ret < 0) ||
+			!goal_in_my_reservation(&my_rsv->rsv_window,
+						grp_goal, group, sb)) {
+			if (my_rsv->rsv_goal_size < *count)
+				my_rsv->rsv_goal_size = *count;
+			ret = alloc_new_reservation(my_rsv, grp_goal, sb,
+							group, bitmap_bh);
+			if (ret < 0)
+				break;			/* failed */
+
+			if (!goal_in_my_reservation(&my_rsv->rsv_window,
+							grp_goal, group, sb))
+				grp_goal = -1;
+		} else if (grp_goal > 0 &&
+			  (my_rsv->rsv_end-grp_goal+1) < *count)
+			try_to_extend_reservation(my_rsv, sb,
+					*count-my_rsv->rsv_end + grp_goal - 1);
+
+		if ((my_rsv->rsv_start > group_last_block) ||
+				(my_rsv->rsv_end < group_first_block)) {
+			rsv_window_dump(&EXT3_SB(sb)->s_rsv_window_root, 1);
+			BUG();
+		}
+		ret = ext3_try_to_allocate(sb, handle, group, bitmap_bh,
+					   grp_goal, &num, &my_rsv->rsv_window);
+		if (ret >= 0) {
+			my_rsv->rsv_alloc_hit += num;
+			*count = num;
+			break;				/* succeed */
+		}
+		num = *count;
+	}
+out:
+	if (ret >= 0) {
+		BUFFER_TRACE(bitmap_bh, "journal_dirty_metadata for "
+					"bitmap block");
+		fatal = ext3_journal_dirty_metadata(handle, bitmap_bh);
+		if (fatal) {
+			*errp = fatal;
+			return -1;
+		}
+		return ret;
+	}
+
+	BUFFER_TRACE(bitmap_bh, "journal_release_buffer");
+	ext3_journal_release_buffer(handle, bitmap_bh);
+	return ret;
+}
+
+/**
+ * ext3_has_free_blocks()
+ * @sbi:		in-core super block structure.
+ *
+ * Check if filesystem has at least 1 free block available for allocation.
+ */
+static int ext3_has_free_blocks(struct ext3_sb_info *sbi)
+{
+	ext3_fsblk_t free_blocks, root_blocks;
+
+	free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
+	root_blocks = le32_to_cpu(sbi->s_es->s_r_blocks_count);
+	if (free_blocks < root_blocks + 1 && !capable(CAP_SYS_RESOURCE) &&
+		sbi->s_resuid != current->fsuid &&
+		(sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) {
+		return 0;
+	}
+	return 1;
+}
+
+/**
+ * ext3_should_retry_alloc()
+ * @sb:			super block
+ * @retries		number of attemps has been made
+ *
+ * ext3_should_retry_alloc() is called when ENOSPC is returned, and if
+ * it is profitable to retry the operation, this function will wait
+ * for the current or commiting transaction to complete, and then
+ * return TRUE.
+ *
+ * if the total number of retries exceed three times, return FALSE.
+ */
+int ext3_should_retry_alloc(struct super_block *sb, int *retries)
+{
+	if (!ext3_has_free_blocks(EXT3_SB(sb)) || (*retries)++ > 3)
+		return 0;
+
+	jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
+
+	return journal_force_commit_nested(EXT3_SB(sb)->s_journal);
+}
+
+/**
+ * ext3_new_blocks() -- core block(s) allocation function
+ * @handle:		handle to this transaction
+ * @inode:		file inode
+ * @goal:		given target block(filesystem wide)
+ * @count:		target number of blocks to allocate
+ * @errp:		error code
+ *
+ * ext3_new_blocks uses a goal block to assist allocation.  It tries to
+ * allocate block(s) from the block group contains the goal block first. If that
+ * fails, it will try to allocate block(s) from other block groups without
+ * any specific goal block.
+ *
+ */
+ext3_fsblk_t ext3_new_blocks(handle_t *handle, struct inode *inode,
+			ext3_fsblk_t goal, unsigned long *count, int *errp)
+{
+	struct buffer_head *bitmap_bh = NULL;
+	struct buffer_head *gdp_bh;
+	int group_no;
+	int goal_group;
+	ext3_grpblk_t grp_target_blk;	/* blockgroup relative goal block */
+	ext3_grpblk_t grp_alloc_blk;	/* blockgroup-relative allocated block*/
+	ext3_fsblk_t ret_block;		/* filesyetem-wide allocated block */
+	int bgi;			/* blockgroup iteration index */
+	int fatal = 0, err;
+	int performed_allocation = 0;
+	ext3_grpblk_t free_blocks;	/* number of free blocks in a group */
+	struct super_block *sb;
+	struct ext3_group_desc *gdp;
+	struct ext3_super_block *es;
+	struct ext3_sb_info *sbi;
+	struct ext3_reserve_window_node *my_rsv = NULL;
+	struct ext3_block_alloc_info *block_i;
+	unsigned short windowsz = 0;
+#ifdef EXT3FS_DEBUG
+	static int goal_hits, goal_attempts;
+#endif
+	unsigned long ngroups;
+	unsigned long num = *count;
+
+	*errp = -ENOSPC;
+	sb = inode->i_sb;
+	if (!sb) {
+		printk("ext3_new_block: nonexistent device");
+		return 0;
+	}
+
+	/*
+	 * Check quota for allocation of this block.
+	 */
+	if (DQUOT_ALLOC_BLOCK(inode, num)) {
+		*errp = -EDQUOT;
+		return 0;
+	}
+
+	sbi = EXT3_SB(sb);
+	es = EXT3_SB(sb)->s_es;
+	ext3_debug("goal=%lu.\n", goal);
+	/*
+	 * Allocate a block from reservation only when
+	 * filesystem is mounted with reservation(default,-o reservation), and
+	 * it's a regular file, and
+	 * the desired window size is greater than 0 (One could use ioctl
+	 * command EXT3_IOC_SETRSVSZ to set the window size to 0 to turn off
+	 * reservation on that particular file)
+	 */
+	block_i = EXT3_I(inode)->i_block_alloc_info;
+	if (block_i && ((windowsz = block_i->rsv_window_node.rsv_goal_size) > 0))
+		my_rsv = &block_i->rsv_window_node;
+
+	if (!ext3_has_free_blocks(sbi)) {
+		*errp = -ENOSPC;
+		goto out;
+	}
+
+	/*
+	 * First, test whether the goal block is free.
+	 */
+	if (goal < le32_to_cpu(es->s_first_data_block) ||
+	    goal >= le32_to_cpu(es->s_blocks_count))
+		goal = le32_to_cpu(es->s_first_data_block);
+	group_no = (goal - le32_to_cpu(es->s_first_data_block)) /
+			EXT3_BLOCKS_PER_GROUP(sb);
+	goal_group = group_no;
+retry_alloc:
+	gdp = ext3_get_group_desc(sb, group_no, &gdp_bh);
+	if (!gdp)
+		goto io_error;
+
+	free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
+	/*
+	 * if there is not enough free blocks to make a new resevation
+	 * turn off reservation for this allocation
+	 */
+	if (my_rsv && (free_blocks < windowsz)
+		&& (rsv_is_empty(&my_rsv->rsv_window)))
+		my_rsv = NULL;
+
+	if (free_blocks > 0) {
+		grp_target_blk = ((goal - le32_to_cpu(es->s_first_data_block)) %
+				EXT3_BLOCKS_PER_GROUP(sb));
+		bitmap_bh = read_block_bitmap(sb, group_no);
+		if (!bitmap_bh)
+			goto io_error;
+		grp_alloc_blk = ext3_try_to_allocate_with_rsv(sb, handle,
+					group_no, bitmap_bh, grp_target_blk,
+					my_rsv,	&num, &fatal);
+		if (fatal)
+			goto out;
+		if (grp_alloc_blk >= 0)
+			goto allocated;
+	}
+
+	ngroups = EXT3_SB(sb)->s_groups_count;
+	smp_rmb();
+
+	/*
+	 * Now search the rest of the groups.  We assume that
+	 * i and gdp correctly point to the last group visited.
+	 */
+	for (bgi = 0; bgi < ngroups; bgi++) {
+		group_no++;
+		if (group_no >= ngroups)
+			group_no = 0;
+		gdp = ext3_get_group_desc(sb, group_no, &gdp_bh);
+		if (!gdp) {
+			*errp = -EIO;
+			goto out;
+		}
+		free_blocks = le16_to_cpu(gdp->bg_free_blocks_count);
+		/*
+		 * skip this group if the number of
+		 * free blocks is less than half of the reservation
+		 * window size.
+		 */
+		if (free_blocks <= (windowsz/2))
+			continue;
+
+		brelse(bitmap_bh);
+		bitmap_bh = read_block_bitmap(sb, group_no);
+		if (!bitmap_bh)
+			goto io_error;
+		/*
+		 * try to allocate block(s) from this group, without a goal(-1).
+		 */
+		grp_alloc_blk = ext3_try_to_allocate_with_rsv(sb, handle,
+					group_no, bitmap_bh, -1, my_rsv,
+					&num, &fatal);
+		if (fatal)
+			goto out;
+		if (grp_alloc_blk >= 0)
+			goto allocated;
+	}
+	/*
+	 * We may end up a bogus ealier ENOSPC error due to
+	 * filesystem is "full" of reservations, but
+	 * there maybe indeed free blocks avaliable on disk
+	 * In this case, we just forget about the reservations
+	 * just do block allocation as without reservations.
+	 */
+	if (my_rsv) {
+		my_rsv = NULL;
+		group_no = goal_group;
+		goto retry_alloc;
+	}
+	/* No space left on the device */
+	*errp = -ENOSPC;
+	goto out;
+
+allocated:
+
+	ext3_debug("using block group %d(%d)\n",
+			group_no, gdp->bg_free_blocks_count);
+
+	BUFFER_TRACE(gdp_bh, "get_write_access");
+	fatal = ext3_journal_get_write_access(handle, gdp_bh);
+	if (fatal)
+		goto out;
+
+	ret_block = grp_alloc_blk + ext3_group_first_block_no(sb, group_no);
+
+	if (in_range(le32_to_cpu(gdp->bg_block_bitmap), ret_block, num) ||
+	    in_range(le32_to_cpu(gdp->bg_inode_bitmap), ret_block, num) ||
+	    in_range(ret_block, le32_to_cpu(gdp->bg_inode_table),
+		      EXT3_SB(sb)->s_itb_per_group) ||
+	    in_range(ret_block + num - 1, le32_to_cpu(gdp->bg_inode_table),
+		      EXT3_SB(sb)->s_itb_per_group))
+		ext3_error(sb, "ext3_new_block",
+			    "Allocating block in system zone - "
+			    "blocks from "E3FSBLK", length %lu",
+			     ret_block, num);
+
+	performed_allocation = 1;
+
+#ifdef CONFIG_JBD_DEBUG
+	{
+		struct buffer_head *debug_bh;
+
+		/* Record bitmap buffer state in the newly allocated block */
+		debug_bh = sb_find_get_block(sb, ret_block);
+		if (debug_bh) {
+			BUFFER_TRACE(debug_bh, "state when allocated");
+			BUFFER_TRACE2(debug_bh, bitmap_bh, "bitmap state");
+			brelse(debug_bh);
+		}
+	}
+	jbd_lock_bh_state(bitmap_bh);
+	spin_lock(sb_bgl_lock(sbi, group_no));
+	if (buffer_jbd(bitmap_bh) && bh2jh(bitmap_bh)->b_committed_data) {
+		int i;
+
+		for (i = 0; i < num; i++) {
+			if (ext3_test_bit(grp_alloc_blk+i,
+					bh2jh(bitmap_bh)->b_committed_data)) {
+				printk("%s: block was unexpectedly set in "
+					"b_committed_data\n", __FUNCTION__);
+			}
+		}
+	}
+	ext3_debug("found bit %d\n", grp_alloc_blk);
+	spin_unlock(sb_bgl_lock(sbi, group_no));
+	jbd_unlock_bh_state(bitmap_bh);
+#endif
+
+	if (ret_block + num - 1 >= le32_to_cpu(es->s_blocks_count)) {
+		ext3_error(sb, "ext3_new_block",
+			    "block("E3FSBLK") >= blocks count(%d) - "
+			    "block_group = %d, es == %p ", ret_block,
+			le32_to_cpu(es->s_blocks_count), group_no, es);
+		goto out;
+	}
+
+	/*
+	 * It is up to the caller to add the new buffer to a journal
+	 * list of some description.  We don't know in advance whether
+	 * the caller wants to use it as metadata or data.
+	 */
+	ext3_debug("allocating block %lu. Goal hits %d of %d.\n",
+			ret_block, goal_hits, goal_attempts);
+
+	spin_lock(sb_bgl_lock(sbi, group_no));
+	gdp->bg_free_blocks_count =
+			cpu_to_le16(le16_to_cpu(gdp->bg_free_blocks_count)-num);
+	spin_unlock(sb_bgl_lock(sbi, group_no));
+	percpu_counter_mod(&sbi->s_freeblocks_counter, -num);
+
+	BUFFER_TRACE(gdp_bh, "journal_dirty_metadata for group descriptor");
+	err = ext3_journal_dirty_metadata(handle, gdp_bh);
+	if (!fatal)
+		fatal = err;
+
+	sb->s_dirt = 1;
+	if (fatal)
+		goto out;
+
+	*errp = 0;
+	brelse(bitmap_bh);
+	DQUOT_FREE_BLOCK(inode, *count-num);
+	*count = num;
+	return ret_block;
+
+io_error:
+	*errp = -EIO;
+out:
+	if (fatal) {
+		*errp = fatal;
+		ext3_std_error(sb, fatal);
+	}
+	/*
+	 * Undo the block allocation
+	 */
+	if (!performed_allocation)
+		DQUOT_FREE_BLOCK(inode, *count);
+	brelse(bitmap_bh);
+	return 0;
+}
+
+ext3_fsblk_t ext3_new_block(handle_t *handle, struct inode *inode,
+			ext3_fsblk_t goal, int *errp)
+{
+	unsigned long count = 1;
+
+	return ext3_new_blocks(handle, inode, goal, &count, errp);
+}
+
+/**
+ * ext3_count_free_blocks() -- count filesystem free blocks
+ * @sb:		superblock
+ *
+ * Adds up the number of free blocks from each block group.
+ */
+ext3_fsblk_t ext3_count_free_blocks(struct super_block *sb)
+{
+	ext3_fsblk_t desc_count;
+	struct ext3_group_desc *gdp;
+	int i;
+	unsigned long ngroups = EXT3_SB(sb)->s_groups_count;
+#ifdef EXT3FS_DEBUG
+	struct ext3_super_block *es;
+	ext3_fsblk_t bitmap_count;
+	unsigned long x;
+	struct buffer_head *bitmap_bh = NULL;
+
+	es = EXT3_SB(sb)->s_es;
+	desc_count = 0;
+	bitmap_count = 0;
+	gdp = NULL;
+
+	smp_rmb();
+	for (i = 0; i < ngroups; i++) {
+		gdp = ext3_get_group_desc(sb, i, NULL);
+		if (!gdp)
+			continue;
+		desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
+		brelse(bitmap_bh);
+		bitmap_bh = read_block_bitmap(sb, i);
+		if (bitmap_bh == NULL)
+			continue;
+
+		x = ext3_count_free(bitmap_bh, sb->s_blocksize);
+		printk("group %d: stored = %d, counted = %lu\n",
+			i, le16_to_cpu(gdp->bg_free_blocks_count), x);
+		bitmap_count += x;
+	}
+	brelse(bitmap_bh);
+	printk("ext3_count_free_blocks: stored = "E3FSBLK
+		", computed = "E3FSBLK", "E3FSBLK"\n",
+	       le32_to_cpu(es->s_free_blocks_count),
+		desc_count, bitmap_count);
+	return bitmap_count;
+#else
+	desc_count = 0;
+	smp_rmb();
+	for (i = 0; i < ngroups; i++) {
+		gdp = ext3_get_group_desc(sb, i, NULL);
+		if (!gdp)
+			continue;
+		desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
+	}
+
+	return desc_count;
+#endif
+}
+
+static inline int
+block_in_use(ext3_fsblk_t block, struct super_block *sb, unsigned char *map)
+{
+	return ext3_test_bit ((block -
+		le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) %
+			 EXT3_BLOCKS_PER_GROUP(sb), map);
+}
+
+static inline int test_root(int a, int b)
+{
+	int num = b;
+
+	while (a > num)
+		num *= b;
+	return num == a;
+}
+
+static int ext3_group_sparse(int group)
+{
+	if (group <= 1)
+		return 1;
+	if (!(group & 1))
+		return 0;
+	return (test_root(group, 7) || test_root(group, 5) ||
+		test_root(group, 3));
+}
+
+/**
+ *	ext3_bg_has_super - number of blocks used by the superblock in group
+ *	@sb: superblock for filesystem
+ *	@group: group number to check
+ *
+ *	Return the number of blocks used by the superblock (primary or backup)
+ *	in this group.  Currently this will be only 0 or 1.
+ */
+int ext3_bg_has_super(struct super_block *sb, int group)
+{
+	if (EXT3_HAS_RO_COMPAT_FEATURE(sb,
+				EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER) &&
+			!ext3_group_sparse(group))
+		return 0;
+	return 1;
+}
+
+static unsigned long ext3_bg_num_gdb_meta(struct super_block *sb, int group)
+{
+	unsigned long metagroup = group / EXT3_DESC_PER_BLOCK(sb);
+	unsigned long first = metagroup * EXT3_DESC_PER_BLOCK(sb);
+	unsigned long last = first + EXT3_DESC_PER_BLOCK(sb) - 1;
+
+	if (group == first || group == first + 1 || group == last)
+		return 1;
+	return 0;
+}
+
+static unsigned long ext3_bg_num_gdb_nometa(struct super_block *sb, int group)
+{
+	if (EXT3_HAS_RO_COMPAT_FEATURE(sb,
+				EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER) &&
+			!ext3_group_sparse(group))
+		return 0;
+	return EXT3_SB(sb)->s_gdb_count;
+}
+
+/**
+ *	ext3_bg_num_gdb - number of blocks used by the group table in group
+ *	@sb: superblock for filesystem
+ *	@group: group number to check
+ *
+ *	Return the number of blocks used by the group descriptor table
+ *	(primary or backup) in this group.  In the future there may be a
+ *	different number of descriptor blocks in each group.
+ */
+unsigned long ext3_bg_num_gdb(struct super_block *sb, int group)
+{
+	unsigned long first_meta_bg =
+			le32_to_cpu(EXT3_SB(sb)->s_es->s_first_meta_bg);
+	unsigned long metagroup = group / EXT3_DESC_PER_BLOCK(sb);
+
+	if (!EXT3_HAS_INCOMPAT_FEATURE(sb,EXT3_FEATURE_INCOMPAT_META_BG) ||
+			metagroup < first_meta_bg)
+		return ext3_bg_num_gdb_nometa(sb,group);
+
+	return ext3_bg_num_gdb_meta(sb,group);
+
+}

fs/ext4/bitmap.c

+/*
+ *  linux/fs/ext3/bitmap.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/jbd.h>
+#include <linux/ext3_fs.h>
+
+#ifdef EXT3FS_DEBUG
+
+static int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
+
+unsigned long ext3_count_free (struct buffer_head * map, unsigned int numchars)
+{
+	unsigned int i;
+	unsigned long sum = 0;
+
+	if (!map)
+		return (0);
+	for (i = 0; i < numchars; i++)
+		sum += nibblemap[map->b_data[i] & 0xf] +
+			nibblemap[(map->b_data[i] >> 4) & 0xf];
+	return (sum);
+}
+
+#endif  /*  EXT3FS_DEBUG  */
+

fs/ext4/dir.c

+/*
+ *  linux/fs/ext3/dir.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/dir.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext3 directory handling functions
+ *
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ *
+ * Hash Tree Directory indexing (c) 2001  Daniel Phillips
+ *
+ */
+
+#include <linux/fs.h>
+#include <linux/jbd.h>
+#include <linux/ext3_fs.h>
+#include <linux/buffer_head.h>
+#include <linux/smp_lock.h>
+#include <linux/slab.h>
+#include <linux/rbtree.h>
+
+static unsigned char ext3_filetype_table[] = {
+	DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
+};
+
+static int ext3_readdir(struct file *, void *, filldir_t);
+static int ext3_dx_readdir(struct file * filp,
+			   void * dirent, filldir_t filldir);
+static int ext3_release_dir (struct inode * inode,
+				struct file * filp);
+
+const struct file_operations ext3_dir_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= generic_read_dir,
+	.readdir	= ext3_readdir,		/* we take BKL. needed?*/
+	.ioctl		= ext3_ioctl,		/* BKL held */
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= ext3_compat_ioctl,
+#endif
+	.fsync		= ext3_sync_file,	/* BKL held */
+#ifdef CONFIG_EXT3_INDEX
+	.release	= ext3_release_dir,
+#endif
+};
+
+
+static unsigned char get_dtype(struct super_block *sb, int filetype)
+{
+	if (!EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_FILETYPE) ||
+	    (filetype >= EXT3_FT_MAX))
+		return DT_UNKNOWN;
+
+	return (ext3_filetype_table[filetype]);
+}
+
+
+int ext3_check_dir_entry (const char * function, struct inode * dir,
+			  struct ext3_dir_entry_2 * de,
+			  struct buffer_head * bh,
+			  unsigned long offset)
+{
+	const char * error_msg = NULL;
+	const int rlen = le16_to_cpu(de->rec_len);
+
+	if (rlen < EXT3_DIR_REC_LEN(1))
+		error_msg = "rec_len is smaller than minimal";
+	else if (rlen % 4 != 0)
+		error_msg = "rec_len % 4 != 0";
+	else if (rlen < EXT3_DIR_REC_LEN(de->name_len))
+		error_msg = "rec_len is too small for name_len";
+	else if (((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize)
+		error_msg = "directory entry across blocks";
+	else if (le32_to_cpu(de->inode) >
+			le32_to_cpu(EXT3_SB(dir->i_sb)->s_es->s_inodes_count))
+		error_msg = "inode out of bounds";
+
+	if (error_msg != NULL)
+		ext3_error (dir->i_sb, function,
+			"bad entry in directory #%lu: %s - "
+			"offset=%lu, inode=%lu, rec_len=%d, name_len=%d",
+			dir->i_ino, error_msg, offset,
+			(unsigned long) le32_to_cpu(de->inode),
+			rlen, de->name_len);
+	return error_msg == NULL ? 1 : 0;
+}
+
+static int ext3_readdir(struct file * filp,
+			 void * dirent, filldir_t filldir)
+{
+	int error = 0;
+	unsigned long offset;
+	int i, stored;
+	struct ext3_dir_entry_2 *de;
+	struct super_block *sb;
+	int err;
+	struct inode *inode = filp->f_dentry->d_inode;
+	int ret = 0;
+
+	sb = inode->i_sb;
+
+#ifdef CONFIG_EXT3_INDEX
+	if (EXT3_HAS_COMPAT_FEATURE(inode->i_sb,
+				    EXT3_FEATURE_COMPAT_DIR_INDEX) &&
+	    ((EXT3_I(inode)->i_flags & EXT3_INDEX_FL) ||
+	     ((inode->i_size >> sb->s_blocksize_bits) == 1))) {
+		err = ext3_dx_readdir(filp, dirent, filldir);
+		if (err != ERR_BAD_DX_DIR) {
+			ret = err;
+			goto out;
+		}
+		/*
+		 * We don't set the inode dirty flag since it's not
+		 * critical that it get flushed back to the disk.
+		 */
+		EXT3_I(filp->f_dentry->d_inode)->i_flags &= ~EXT3_INDEX_FL;
+	}
+#endif
+	stored = 0;
+	offset = filp->f_pos & (sb->s_blocksize - 1);
+
+	while (!error && !stored && filp->f_pos < inode->i_size) {
+		unsigned long blk = filp->f_pos >> EXT3_BLOCK_SIZE_BITS(sb);
+		struct buffer_head map_bh;
+		struct buffer_head *bh = NULL;
+
+		map_bh.b_state = 0;
+		err = ext3_get_blocks_handle(NULL, inode, blk, 1,
+						&map_bh, 0, 0);
+		if (err > 0) {
+			page_cache_readahead(sb->s_bdev->bd_inode->i_mapping,
+				&filp->f_ra,
+				filp,
+				map_bh.b_blocknr >>
+					(PAGE_CACHE_SHIFT - inode->i_blkbits),
+				1);
+			bh = ext3_bread(NULL, inode, blk, 0, &err);
+		}
+
+		/*
+		 * We ignore I/O errors on directories so users have a chance
+		 * of recovering data when there's a bad sector
+		 */
+		if (!bh) {
+			ext3_error (sb, "ext3_readdir",
+				"directory #%lu contains a hole at offset %lu",
+				inode->i_ino, (unsigned long)filp->f_pos);
+			filp->f_pos += sb->s_blocksize - offset;
+			continue;
+		}
+
+revalidate:
+		/* If the dir block has changed since the last call to
+		 * readdir(2), then we might be pointing to an invalid
+		 * dirent right now.  Scan from the start of the block
+		 * to make sure. */
+		if (filp->f_version != inode->i_version) {
+			for (i = 0; i < sb->s_blocksize && i < offset; ) {
+				de = (struct ext3_dir_entry_2 *)
+					(bh->b_data + i);
+				/* It's too expensive to do a full
+				 * dirent test each time round this
+				 * loop, but we do have to test at
+				 * least that it is non-zero.  A
+				 * failure will be detected in the
+				 * dirent test below. */
+				if (le16_to_cpu(de->rec_len) <
+						EXT3_DIR_REC_LEN(1))
+					break;
+				i += le16_to_cpu(de->rec_len);
+			}
+			offset = i;
+			filp->f_pos = (filp->f_pos & ~(sb->s_blocksize - 1))
+				| offset;
+			filp->f_version = inode->i_version;
+		}
+
+		while (!error && filp->f_pos < inode->i_size
+		       && offset < sb->s_blocksize) {
+			de = (struct ext3_dir_entry_2 *) (bh->b_data + offset);
+			if (!ext3_check_dir_entry ("ext3_readdir", inode, de,
+						   bh, offset)) {
+				/* On error, skip the f_pos to the
+                                   next block. */
+				filp->f_pos = (filp->f_pos |
+						(sb->s_blocksize - 1)) + 1;
+				brelse (bh);
+				ret = stored;
+				goto out;
+			}
+			offset += le16_to_cpu(de->rec_len);
+			if (le32_to_cpu(de->inode)) {
+				/* We might block in the next section
+				 * if the data destination is
+				 * currently swapped out.  So, use a
+				 * version stamp to detect whether or
+				 * not the directory has been modified
+				 * during the copy operation.
+				 */
+				unsigned long version = filp->f_version;
+
+				error = filldir(dirent, de->name,
+						de->name_len,
+						filp->f_pos,
+						le32_to_cpu(de->inode),
+						get_dtype(sb, de->file_type));
+				if (error)
+					break;
+				if (version != filp->f_version)
+					goto revalidate;
+				stored ++;
+			}
+			filp->f_pos += le16_to_cpu(de->rec_len);
+		}
+		offset = 0;
+		brelse (bh);
+	}
+out:
+	return ret;
+}
+
+#ifdef CONFIG_EXT3_INDEX
+/*
+ * These functions convert from the major/minor hash to an f_pos
+ * value.
+ *
+ * Currently we only use major hash numer.  This is unfortunate, but
+ * on 32-bit machines, the same VFS interface is used for lseek and
+ * llseek, so if we use the 64 bit offset, then the 32-bit versions of
+ * lseek/telldir/seekdir will blow out spectacularly, and from within
+ * the ext2 low-level routine, we don't know if we're being called by
+ * a 64-bit version of the system call or the 32-bit version of the
+ * system call.  Worse yet, NFSv2 only allows for a 32-bit readdir
+ * cookie.  Sigh.
+ */
+#define hash2pos(major, minor)	(major >> 1)
+#define pos2maj_hash(pos)	((pos << 1) & 0xffffffff)
+#define pos2min_hash(pos)	(0)
+
+/*
+ * This structure holds the nodes of the red-black tree used to store
+ * the directory entry in hash order.
+ */
+struct fname {
+	__u32		hash;
+	__u32		minor_hash;
+	struct rb_node	rb_hash;
+	struct fname	*next;
+	__u32		inode;
+	__u8		name_len;
+	__u8		file_type;
+	char		name[0];
+};
+
+/*
+ * This functoin implements a non-recursive way of freeing all of the
+ * nodes in the red-black tree.
+ */
+static void free_rb_tree_fname(struct rb_root *root)
+{
+	struct rb_node	*n = root->rb_node;
+	struct rb_node	*parent;
+	struct fname	*fname;
+
+	while (n) {
+		/* Do the node's children first */
+		if ((n)->rb_left) {
+			n = n->rb_left;
+			continue;
+		}
+		if (n->rb_right) {
+			n = n->rb_right;
+			continue;
+		}
+		/*
+		 * The node has no children; free it, and then zero
+		 * out parent's link to it.  Finally go to the
+		 * beginning of the loop and try to free the parent
+		 * node.
+		 */
+		parent = rb_parent(n);
+		fname = rb_entry(n, struct fname, rb_hash);
+		while (fname) {
+			struct fname * old = fname;
+			fname = fname->next;
+			kfree (old);
+		}
+		if (!parent)
+			root->rb_node = NULL;
+		else if (parent->rb_left == n)
+			parent->rb_left = NULL;
+		else if (parent->rb_right == n)
+			parent->rb_right = NULL;
+		n = parent;
+	}
+	root->rb_node = NULL;
+}
+
+
+static struct dir_private_info *create_dir_info(loff_t pos)
+{
+	struct dir_private_info *p;
+
+	p = kmalloc(sizeof(struct dir_private_info), GFP_KERNEL);
+	if (!p)
+		return NULL;
+	p->root.rb_node = NULL;
+	p->curr_node = NULL;
+	p->extra_fname = NULL;
+	p->last_pos = 0;
+	p->curr_hash = pos2maj_hash(pos);
+	p->curr_minor_hash = pos2min_hash(pos);
+	p->next_hash = 0;
+	return p;
+}
+
+void ext3_htree_free_dir_info(struct dir_private_info *p)
+{
+	free_rb_tree_fname(&p->root);
+	kfree(p);
+}
+
+/*
+ * Given a directory entry, enter it into the fname rb tree.
+ */
+int ext3_htree_store_dirent(struct file *dir_file, __u32 hash,
+			     __u32 minor_hash,
+			     struct ext3_dir_entry_2 *dirent)
+{
+	struct rb_node **p, *parent = NULL;
+	struct fname * fname, *new_fn;
+	struct dir_private_info *info;
+	int len;
+
+	info = (struct dir_private_info *) dir_file->private_data;
+	p = &info->root.rb_node;
+
+	/* Create and allocate the fname structure */
+	len = sizeof(struct fname) + dirent->name_len + 1;
+	new_fn = kzalloc(len, GFP_KERNEL);
+	if (!new_fn)
+		return -ENOMEM;
+	new_fn->hash = hash;
+	new_fn->minor_hash = minor_hash;
+	new_fn->inode = le32_to_cpu(dirent->inode);
+	new_fn->name_len = dirent->name_len;
+	new_fn->file_type = dirent->file_type;
+	memcpy(new_fn->name, dirent->name, dirent->name_len);
+	new_fn->name[dirent->name_len] = 0;
+
+	while (*p) {
+		parent = *p;
+		fname = rb_entry(parent, struct fname, rb_hash);
+
+		/*
+		 * If the hash and minor hash match up, then we put
+		 * them on a linked list.  This rarely happens...
+		 */
+		if ((new_fn->hash == fname->hash) &&
+		    (new_fn->minor_hash == fname->minor_hash)) {
+			new_fn->next = fname->next;
+			fname->next = new_fn;
+			return 0;
+		}
+
+		if (new_fn->hash < fname->hash)
+			p = &(*p)->rb_left;
+		else if (new_fn->hash > fname->hash)
+			p = &(*p)->rb_right;
+		else if (new_fn->minor_hash < fname->minor_hash)
+			p = &(*p)->rb_left;
+		else /* if (new_fn->minor_hash > fname->minor_hash) */
+			p = &(*p)->rb_right;
+	}
+
+	rb_link_node(&new_fn->rb_hash, parent, p);
+	rb_insert_color(&new_fn->rb_hash, &info->root);
+	return 0;
+}
+
+
+
+/*
+ * This is a helper function for ext3_dx_readdir.  It calls filldir
+ * for all entres on the fname linked list.  (Normally there is only
+ * one entry on the linked list, unless there are 62 bit hash collisions.)
+ */
+static int call_filldir(struct file * filp, void * dirent,
+			filldir_t filldir, struct fname *fname)
+{
+	struct dir_private_info *info = filp->private_data;
+	loff_t	curr_pos;
+	struct inode *inode = filp->f_dentry->d_inode;
+	struct super_block * sb;
+	int error;
+
+	sb = inode->i_sb;
+
+	if (!fname) {
+		printk("call_filldir: called with null fname?!?\n");
+		return 0;
+	}
+	curr_pos = hash2pos(fname->hash, fname->minor_hash);
+	while (fname) {
+		error = filldir(dirent, fname->name,
+				fname->name_len, curr_pos,
+				fname->inode,
+				get_dtype(sb, fname->file_type));
+		if (error) {
+			filp->f_pos = curr_pos;
+			info->extra_fname = fname->next;
+			return error;
+		}
+		fname = fname->next;
+	}
+	return 0;
+}
+
+static int ext3_dx_readdir(struct file * filp,
+			 void * dirent, filldir_t filldir)
+{
+	struct dir_private_info *info = filp->private_data;
+	struct inode *inode = filp->f_dentry->d_inode;
+	struct fname *fname;
+	int	ret;
+
+	if (!info) {
+		info = create_dir_info(filp->f_pos);
+		if (!info)
+			return -ENOMEM;
+		filp->private_data = info;
+	}
+
+	if (filp->f_pos == EXT3_HTREE_EOF)
+		return 0;	/* EOF */
+
+	/* Some one has messed with f_pos; reset the world */
+	if (info->last_pos != filp->f_pos) {
+		free_rb_tree_fname(&info->root);
+		info->curr_node = NULL;
+		info->extra_fname = NULL;
+		info->curr_hash = pos2maj_hash(filp->f_pos);
+		info->curr_minor_hash = pos2min_hash(filp->f_pos);
+	}
+
+	/*
+	 * If there are any leftover names on the hash collision
+	 * chain, return them first.
+	 */
+	if (info->extra_fname &&
+	    call_filldir(filp, dirent, filldir, info->extra_fname))
+		goto finished;
+
+	if (!info->curr_node)
+		info->curr_node = rb_first(&info->root);
+
+	while (1) {
+		/*
+		 * Fill the rbtree if we have no more entries,
+		 * or the inode has changed since we last read in the
+		 * cached entries.
+		 */
+		if ((!info->curr_node) ||
+		    (filp->f_version != inode->i_version)) {
+			info->curr_node = NULL;
+			free_rb_tree_fname(&info->root);
+			filp->f_version = inode->i_version;
+			ret = ext3_htree_fill_tree(filp, info->curr_hash,
+						   info->curr_minor_hash,
+						   &info->next_hash);
+			if (ret < 0)
+				return ret;
+			if (ret == 0) {
+				filp->f_pos = EXT3_HTREE_EOF;
+				break;
+			}
+			info->curr_node = rb_first(&info->root);
+		}
+
+		fname = rb_entry(info->curr_node, struct fname, rb_hash);
+		info->curr_hash = fname->hash;
+		info->curr_minor_hash = fname->minor_hash;
+		if (call_filldir(filp, dirent, filldir, fname))
+			break;
+
+		info->curr_node = rb_next(info->curr_node);
+		if (!info->curr_node) {
+			if (info->next_hash == ~0) {
+				filp->f_pos = EXT3_HTREE_EOF;
+				break;
+			}
+			info->curr_hash = info->next_hash;
+			info->curr_minor_hash = 0;
+		}
+	}
+finished:
+	info->last_pos = filp->f_pos;
+	return 0;
+}
+
+static int ext3_release_dir (struct inode * inode, struct file * filp)
+{
+       if (filp->private_data)
+		ext3_htree_free_dir_info(filp->private_data);
+
+	return 0;
+}
+
+#endif

fs/ext4/file.c

+/*
+ *  linux/fs/ext3/file.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/file.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext3 fs regular file handling primitives
+ *
+ *  64-bit file support on 64-bit platforms by Jakub Jelinek
+ *	(jj@sunsite.ms.mff.cuni.cz)
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/jbd.h>
+#include <linux/ext3_fs.h>
+#include <linux/ext3_jbd.h>
+#include "xattr.h"
+#include "acl.h"
+
+/*
+ * Called when an inode is released. Note that this is different
+ * from ext3_file_open: open gets called at every open, but release
+ * gets called only when /all/ the files are closed.
+ */
+static int ext3_release_file (struct inode * inode, struct file * filp)
+{
+	/* if we are the last writer on the inode, drop the block reservation */
+	if ((filp->f_mode & FMODE_WRITE) &&
+			(atomic_read(&inode->i_writecount) == 1))
+	{
+		mutex_lock(&EXT3_I(inode)->truncate_mutex);
+		ext3_discard_reservation(inode);
+		mutex_unlock(&EXT3_I(inode)->truncate_mutex);
+	}
+	if (is_dx(inode) && filp->private_data)
+		ext3_htree_free_dir_info(filp->private_data);
+
+	return 0;
+}
+
+static ssize_t
+ext3_file_write(struct kiocb *iocb, const struct iovec *iov,
+		unsigned long nr_segs, loff_t pos)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file->f_dentry->d_inode;
+	ssize_t ret;
+	int err;
+
+	ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
+
+	/*
+	 * Skip flushing if there was an error, or if nothing was written.
+	 */
+	if (ret <= 0)
+		return ret;
+
+	/*
+	 * If the inode is IS_SYNC, or is O_SYNC and we are doing data
+	 * journalling then we need to make sure that we force the transaction
+	 * to disk to keep all metadata uptodate synchronously.
+	 */
+	if (file->f_flags & O_SYNC) {
+		/*
+		 * If we are non-data-journaled, then the dirty data has
+		 * already been flushed to backing store by generic_osync_inode,
+		 * and the inode has been flushed too if there have been any
+		 * modifications other than mere timestamp updates.
+		 *
+		 * Open question --- do we care about flushing timestamps too
+		 * if the inode is IS_SYNC?
+		 */
+		if (!ext3_should_journal_data(inode))
+			return ret;
+
+		goto force_commit;
+	}
+
+	/*
+	 * So we know that there has been no forced data flush.  If the inode
+	 * is marked IS_SYNC, we need to force one ourselves.
+	 */
+	if (!IS_SYNC(inode))
+		return ret;
+
+	/*
+	 * Open question #2 --- should we force data to disk here too?  If we
+	 * don't, the only impact is that data=writeback filesystems won't
+	 * flush data to disk automatically on IS_SYNC, only metadata (but
+	 * historically, that is what ext2 has done.)
+	 */
+
+force_commit:
+	err = ext3_force_commit(inode->i_sb);
+	if (err)
+		return err;
+	return ret;
+}
+
+const struct file_operations ext3_file_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= do_sync_read,
+	.write		= do_sync_write,
+	.aio_read	= generic_file_aio_read,
+	.aio_write	= ext3_file_write,
+	.ioctl		= ext3_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= ext3_compat_ioctl,
+#endif
+	.mmap		= generic_file_mmap,
+	.open		= generic_file_open,
+	.release	= ext3_release_file,
+	.fsync		= ext3_sync_file,
+	.sendfile	= generic_file_sendfile,
+	.splice_read	= generic_file_splice_read,
+	.splice_write	= generic_file_splice_write,
+};
+
+struct inode_operations ext3_file_inode_operations = {
+	.truncate	= ext3_truncate,
+	.setattr	= ext3_setattr,
+#ifdef CONFIG_EXT3_FS_XATTR
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= ext3_listxattr,
+	.removexattr	= generic_removexattr,
+#endif
+	.permission	= ext3_permission,
+};
+

fs/ext4/fsync.c

+/*
+ *  linux/fs/ext3/fsync.c
+ *
+ *  Copyright (C) 1993  Stephen Tweedie (sct@redhat.com)
+ *  from
+ *  Copyright (C) 1992  Remy Card (card@masi.ibp.fr)
+ *                      Laboratoire MASI - Institut Blaise Pascal
+ *                      Universite Pierre et Marie Curie (Paris VI)
+ *  from
+ *  linux/fs/minix/truncate.c   Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext3fs fsync primitive
+ *
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ *
+ *  Removed unnecessary code duplication for little endian machines
+ *  and excessive __inline__s.
+ *        Andi Kleen, 1997
+ *
+ * Major simplications and cleanup - we only need to do the metadata, because
+ * we can depend on generic_block_fdatasync() to sync the data blocks.
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/writeback.h>
+#include <linux/jbd.h>
+#include <linux/ext3_fs.h>
+#include <linux/ext3_jbd.h>
+
+/*
+ * akpm: A new design for ext3_sync_file().
+ *
+ * This is only called from sys_fsync(), sys_fdatasync() and sys_msync().
+ * There cannot be a transaction open by this task.
+ * Another task could have dirtied this inode.  Its data can be in any
+ * state in the journalling system.
+ *
+ * What we do is just kick off a commit and wait on it.  This will snapshot the
+ * inode to disk.
+ */
+
+int ext3_sync_file(struct file * file, struct dentry *dentry, int datasync)
+{
+	struct inode *inode = dentry->d_inode;
+	int ret = 0;
+
+	J_ASSERT(ext3_journal_current_handle() == 0);
+
+	/*
+	 * data=writeback:
+	 *  The caller's filemap_fdatawrite()/wait will sync the data.
+	 *  sync_inode() will sync the metadata
+	 *
+	 * data=ordered:
+	 *  The caller's filemap_fdatawrite() will write the data and
+	 *  sync_inode() will write the inode if it is dirty.  Then the caller's
+	 *  filemap_fdatawait() will wait on the pages.
+	 *
+	 * data=journal:
+	 *  filemap_fdatawrite won't do anything (the buffers are clean).
+	 *  ext3_force_commit will write the file data into the journal and
+	 *  will wait on that.
+	 *  filemap_fdatawait() will encounter a ton of newly-dirtied pages
+	 *  (they were dirtied by commit).  But that's OK - the blocks are
+	 *  safe in-journal, which is all fsync() needs to ensure.
+	 */
+	if (ext3_should_journal_data(inode)) {
+		ret = ext3_force_commit(inode->i_sb);
+		goto out;
+	}
+
+	/*
+	 * The VFS has written the file data.  If the inode is unaltered
+	 * then we need not start a commit.
+	 */
+	if (inode->i_state & (I_DIRTY_SYNC|I_DIRTY_DATASYNC)) {
+		struct writeback_control wbc = {
+			.sync_mode = WB_SYNC_ALL,
+			.nr_to_write = 0, /* sys_fsync did this */
+		};
+		ret = sync_inode(inode, &wbc);
+	}
+out:
+	return ret;
+}

fs/ext4/hash.c

+/*
+ *  linux/fs/ext3/hash.c
+ *
+ * Copyright (C) 2002 by Theodore Ts'o
+ *
+ * This file is released under the GPL v2.
+ *
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ */
+
+#include <linux/fs.h>
+#include <linux/jbd.h>
+#include <linux/sched.h>
+#include <linux/ext3_fs.h>
+#include <linux/cryptohash.h>
+
+#define DELTA 0x9E3779B9
+
+static void TEA_transform(__u32 buf[4], __u32 const in[])
+{
+	__u32	sum = 0;
+	__u32	b0 = buf[0], b1 = buf[1];
+	__u32	a = in[0], b = in[1], c = in[2], d = in[3];
+	int	n = 16;
+
+	do {
+		sum += DELTA;
+		b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b);
+		b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d);
+	} while(--n);
+
+	buf[0] += b0;
+	buf[1] += b1;
+}
+
+
+/* The old legacy hash */
+static __u32 dx_hack_hash (const char *name, int len)
+{
+	__u32 hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
+	while (len--) {
+		__u32 hash = hash1 + (hash0 ^ (*name++ * 7152373));
+
+		if (hash & 0x80000000) hash -= 0x7fffffff;
+		hash1 = hash0;
+		hash0 = hash;
+	}
+	return (hash0 << 1);
+}
+
+static void str2hashbuf(const char *msg, int len, __u32 *buf, int num)
+{
+	__u32	pad, val;
+	int	i;
+
+	pad = (__u32)len | ((__u32)len << 8);
+	pad |= pad << 16;
+
+	val = pad;
+	if (len > num*4)
+		len = num * 4;
+	for (i=0; i < len; i++) {
+		if ((i % 4) == 0)
+			val = pad;
+		val = msg[i] + (val << 8);
+		if ((i % 4) == 3) {
+			*buf++ = val;
+			val = pad;
+			num--;
+		}
+	}
+	if (--num >= 0)
+		*buf++ = val;
+	while (--num >= 0)
+		*buf++ = pad;
+}
+
+/*
+ * Returns the hash of a filename.  If len is 0 and name is NULL, then
+ * this function can be used to test whether or not a hash version is
+ * supported.
+ *
+ * The seed is an 4 longword (32 bits) "secret" which can be used to
+ * uniquify a hash.  If the seed is all zero's, then some default seed
+ * may be used.
+ *
+ * A particular hash version specifies whether or not the seed is
+ * represented, and whether or not the returned hash is 32 bits or 64
+ * bits.  32 bit hashes will return 0 for the minor hash.
+ */
+int ext3fs_dirhash(const char *name, int len, struct dx_hash_info *hinfo)
+{
+	__u32	hash;
+	__u32	minor_hash = 0;
+	const char	*p;
+	int		i;
+	__u32		in[8], buf[4];
+
+	/* Initialize the default seed for the hash checksum functions */
+	buf[0] = 0x67452301;
+	buf[1] = 0xefcdab89;
+	buf[2] = 0x98badcfe;
+	buf[3] = 0x10325476;
+
+	/* Check to see if the seed is all zero's */
+	if (hinfo->seed) {
+		for (i=0; i < 4; i++) {
+			if (hinfo->seed[i])
+				break;
+		}
+		if (i < 4)
+			memcpy(buf, hinfo->seed, sizeof(buf));
+	}
+
+	switch (hinfo->hash_version) {
+	case DX_HASH_LEGACY:
+		hash = dx_hack_hash(name, len);
+		break;
+	case DX_HASH_HALF_MD4:
+		p = name;
+		while (len > 0) {
+			str2hashbuf(p, len, in, 8);
+			half_md4_transform(buf, in);
+			len -= 32;
+			p += 32;
+		}
+		minor_hash = buf[2];
+		hash = buf[1];
+		break;
+	case DX_HASH_TEA:
+		p = name;
+		while (len > 0) {
+			str2hashbuf(p, len, in, 4);
+			TEA_transform(buf, in);
+			len -= 16;
+			p += 16;
+		}
+		hash = buf[0];
+		minor_hash = buf[1];
+		break;
+	default:
+		hinfo->hash = 0;
+		return -1;
+	}
+	hash = hash & ~1;
+	if (hash == (EXT3_HTREE_EOF << 1))
+		hash = (EXT3_HTREE_EOF-1) << 1;
+	hinfo->hash = hash;
+	hinfo->minor_hash = minor_hash;
+	return 0;
+}

fs/ext4/ialloc.c

+/*
+ *  linux/fs/ext3/ialloc.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  BSD ufs-inspired inode and directory allocation by
+ *  Stephen Tweedie (sct@redhat.com), 1993
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/jbd.h>
+#include <linux/ext3_fs.h>
+#include <linux/ext3_jbd.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/quotaops.h>
+#include <linux/buffer_head.h>
+#include <linux/random.h>
+#include <linux/bitops.h>
+
+#include <asm/byteorder.h>
+
+#include "xattr.h"
+#include "acl.h"
+
+/*
+ * ialloc.c contains the inodes allocation and deallocation routines
+ */
+
+/*
+ * The free inodes are managed by bitmaps.  A file system contains several
+ * blocks groups.  Each group contains 1 bitmap block for blocks, 1 bitmap
+ * block for inodes, N blocks for the inode table and data blocks.
+ *
+ * The file system contains group descriptors which are located after the
+ * super block.  Each descriptor contains the number of the bitmap block and
+ * the free blocks count in the block.
+ */
+
+
+/*
+ * Read the inode allocation bitmap for a given block_group, reading
+ * into the specified slot in the superblock's bitmap cache.
+ *
+ * Return buffer_head of bitmap on success or NULL.
+ */
+static struct buffer_head *
+read_inode_bitmap(struct super_block * sb, unsigned long block_group)
+{
+	struct ext3_group_desc *desc;
+	struct buffer_head *bh = NULL;
+
+	desc = ext3_get_group_desc(sb, block_group, NULL);
+	if (!desc)
+		goto error_out;
+
+	bh = sb_bread(sb, le32_to_cpu(desc->bg_inode_bitmap));
+	if (!bh)
+		ext3_error(sb, "read_inode_bitmap",
+			    "Cannot read inode bitmap - "
+			    "block_group = %lu, inode_bitmap = %u",
+			    block_group, le32_to_cpu(desc->bg_inode_bitmap));
+error_out:
+	return bh;
+}
+
+/*
+ * NOTE! When we get the inode, we're the only people
+ * that have access to it, and as such there are no
+ * race conditions we have to worry about. The inode
+ * is not on the hash-lists, and it cannot be reached
+ * through the filesystem because the directory entry
+ * has been deleted earlier.
+ *
+ * HOWEVER: we must make sure that we get no aliases,
+ * which means that we have to call "clear_inode()"
+ * _before_ we mark the inode not in use in the inode
+ * bitmaps. Otherwise a newly created file might use
+ * the same inode number (not actually the same pointer
+ * though), and then we'd have two inodes sharing the
+ * same inode number and space on the harddisk.
+ */
+void ext3_free_inode (handle_t *handle, struct inode * inode)
+{
+	struct super_block * sb = inode->i_sb;
+	int is_directory;
+	unsigned long ino;
+	struct buffer_head *bitmap_bh = NULL;
+	struct buffer_head *bh2;
+	unsigned long block_group;
+	unsigned long bit;
+	struct ext3_group_desc * gdp;
+	struct ext3_super_block * es;
+	struct ext3_sb_info *sbi;
+	int fatal = 0, err;
+
+	if (atomic_read(&inode->i_count) > 1) {
+		printk ("ext3_free_inode: inode has count=%d\n",
+					atomic_read(&inode->i_count));
+		return;
+	}
+	if (inode->i_nlink) {
+		printk ("ext3_free_inode: inode has nlink=%d\n",
+			inode->i_nlink);
+		return;
+	}
+	if (!sb) {
+		printk("ext3_free_inode: inode on nonexistent device\n");
+		return;
+	}
+	sbi = EXT3_SB(sb);
+
+	ino = inode->i_ino;
+	ext3_debug ("freeing inode %lu\n", ino);
+
+	/*
+	 * Note: we must free any quota before locking the superblock,
+	 * as writing the quota to disk may need the lock as well.
+	 */
+	DQUOT_INIT(inode);
+	ext3_xattr_delete_inode(handle, inode);
+	DQUOT_FREE_INODE(inode);
+	DQUOT_DROP(inode);
+
+	is_directory = S_ISDIR(inode->i_mode);
+
+	/* Do this BEFORE marking the inode not in use or returning an error */
+	clear_inode (inode);
+
+	es = EXT3_SB(sb)->s_es;
+	if (ino < EXT3_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
+		ext3_error (sb, "ext3_free_inode",
+			    "reserved or nonexistent inode %lu", ino);
+		goto error_return;
+	}
+	block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
+	bit = (ino - 1) % EXT3_INODES_PER_GROUP(sb);
+	bitmap_bh = read_inode_bitmap(sb, block_group);
+	if (!bitmap_bh)
+		goto error_return;
+
+	BUFFER_TRACE(bitmap_bh, "get_write_access");
+	fatal = ext3_journal_get_write_access(handle, bitmap_bh);
+	if (fatal)
+		goto error_return;
+
+	/* Ok, now we can actually update the inode bitmaps.. */
+	if (!ext3_clear_bit_atomic(sb_bgl_lock(sbi, block_group),
+					bit, bitmap_bh->b_data))
+		ext3_error (sb, "ext3_free_inode",
+			      "bit already cleared for inode %lu", ino);
+	else {
+		gdp = ext3_get_group_desc (sb, block_group, &bh2);
+
+		BUFFER_TRACE(bh2, "get_write_access");
+		fatal = ext3_journal_get_write_access(handle, bh2);
+		if (fatal) goto error_return;
+
+		if (gdp) {
+			spin_lock(sb_bgl_lock(sbi, block_group));
+			gdp->bg_free_inodes_count = cpu_to_le16(
+				le16_to_cpu(gdp->bg_free_inodes_count) + 1);
+			if (is_directory)
+				gdp->bg_used_dirs_count = cpu_to_le16(
+				  le16_to_cpu(gdp->bg_used_dirs_count) - 1);
+			spin_unlock(sb_bgl_lock(sbi, block_group));
+			percpu_counter_inc(&sbi->s_freeinodes_counter);
+			if (is_directory)
+				percpu_counter_dec(&sbi->s_dirs_counter);
+
+		}
+		BUFFER_TRACE(bh2, "call ext3_journal_dirty_metadata");
+		err = ext3_journal_dirty_metadata(handle, bh2);
+		if (!fatal) fatal = err;
+	}
+	BUFFER_TRACE(bitmap_bh, "call ext3_journal_dirty_metadata");
+	err = ext3_journal_dirty_metadata(handle, bitmap_bh);
+	if (!fatal)
+		fatal = err;
+	sb->s_dirt = 1;
+error_return:
+	brelse(bitmap_bh);
+	ext3_std_error(sb, fatal);
+}
+
+/*
+ * There are two policies for allocating an inode.  If the new inode is
+ * a directory, then a forward search is made for a block group with both
+ * free space and a low directory-to-inode ratio; if that fails, then of
+ * the groups with above-average free space, that group with the fewest
+ * directories already is chosen.
+ *
+ * For other inodes, search forward from the parent directory\'s block
+ * group to find a free inode.
+ */
+static int find_group_dir(struct super_block *sb, struct inode *parent)
+{
+	int ngroups = EXT3_SB(sb)->s_groups_count;
+	unsigned int freei, avefreei;
+	struct ext3_group_desc *desc, *best_desc = NULL;
+	struct buffer_head *bh;
+	int group, best_group = -1;
+
+	freei = percpu_counter_read_positive(&EXT3_SB(sb)->s_freeinodes_counter);
+	avefreei = freei / ngroups;
+
+	for (group = 0; group < ngroups; group++) {
+		desc = ext3_get_group_desc (sb, group, &bh);
+		if (!desc || !desc->bg_free_inodes_count)
+			continue;
+		if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
+			continue;
+		if (!best_desc ||
+		    (le16_to_cpu(desc->bg_free_blocks_count) >
+		     le16_to_cpu(best_desc->bg_free_blocks_count))) {
+			best_group = group;
+			best_desc = desc;
+		}
+	}
+	return best_group;
+}
+
+/*
+ * Orlov's allocator for directories.
+ *
+ * We always try to spread first-level directories.
+ *
+ * If there are blockgroups with both free inodes and free blocks counts
+ * not worse than average we return one with smallest directory count.
+ * Otherwise we simply return a random group.
+ *
+ * For the rest rules look so:
+ *
+ * It's OK to put directory into a group unless
+ * it has too many directories already (max_dirs) or
+ * it has too few free inodes left (min_inodes) or
+ * it has too few free blocks left (min_blocks) or
+ * it's already running too large debt (max_debt).
+ * Parent's group is prefered, if it doesn't satisfy these
+ * conditions we search cyclically through the rest. If none
+ * of the groups look good we just look for a group with more
+ * free inodes than average (starting at parent's group).
+ *
+ * Debt is incremented each time we allocate a directory and decremented
+ * when we allocate an inode, within 0--255.
+ */
+
+#define INODE_COST 64
+#define BLOCK_COST 256
+
+static int find_group_orlov(struct super_block *sb, struct inode *parent)
+{
+	int parent_group = EXT3_I(parent)->i_block_group;
+	struct ext3_sb_info *sbi = EXT3_SB(sb);
+	struct ext3_super_block *es = sbi->s_es;
+	int ngroups = sbi->s_groups_count;
+	int inodes_per_group = EXT3_INODES_PER_GROUP(sb);
+	unsigned int freei, avefreei;
+	ext3_fsblk_t freeb, avefreeb;
+	ext3_fsblk_t blocks_per_dir;
+	unsigned int ndirs;
+	int max_debt, max_dirs, min_inodes;
+	ext3_grpblk_t min_blocks;
+	int group = -1, i;
+	struct ext3_group_desc *desc;
+	struct buffer_head *bh;
+
+	freei = percpu_counter_read_positive(&sbi->s_freeinodes_counter);
+	avefreei = freei / ngroups;
+	freeb = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
+	avefreeb = freeb / ngroups;
+	ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
+
+	if ((parent == sb->s_root->d_inode) ||
+	    (EXT3_I(parent)->i_flags & EXT3_TOPDIR_FL)) {
+		int best_ndir = inodes_per_group;
+		int best_group = -1;
+
+		get_random_bytes(&group, sizeof(group));
+		parent_group = (unsigned)group % ngroups;
+		for (i = 0; i < ngroups; i++) {
+			group = (parent_group + i) % ngroups;
+			desc = ext3_get_group_desc (sb, group, &bh);
+			if (!desc || !desc->bg_free_inodes_count)
+				continue;
+			if (le16_to_cpu(desc->bg_used_dirs_count) >= best_ndir)
+				continue;
+			if (le16_to_cpu(desc->bg_free_inodes_count) < avefreei)
+				continue;
+			if (le16_to_cpu(desc->bg_free_blocks_count) < avefreeb)
+				continue;
+			best_group = group;
+			best_ndir = le16_to_cpu(desc->bg_used_dirs_count);
+		}
+		if (best_group >= 0)
+			return best_group;
+		goto fallback;
+	}
+
+	blocks_per_dir = (le32_to_cpu(es->s_blocks_count) - freeb) / ndirs;
+
+	max_dirs = ndirs / ngroups + inodes_per_group / 16;
+	min_inodes = avefreei - inodes_per_group / 4;
+	min_blocks = avefreeb - EXT3_BLOCKS_PER_GROUP(sb) / 4;
+
+	max_debt = EXT3_BLOCKS_PER_GROUP(sb) / max(blocks_per_dir, (ext3_fsblk_t)BLOCK_COST);
+	if (max_debt * INODE_COST > inodes_per_group)
+		max_debt = inodes_per_group / INODE_COST;
+	if (max_debt > 255)
+		max_debt = 255;
+	if (max_debt == 0)
+		max_debt = 1;
+
+	for (i = 0; i < ngroups; i++) {
+		group = (parent_group + i) % ngroups;
+		desc = ext3_get_group_desc (sb, group, &bh);
+		if (!desc || !desc->bg_free_inodes_count)
+			continue;
+		if (le16_to_cpu(desc->bg_used_dirs_count) >= max_dirs)
+			continue;
+		if (le16_to_cpu(desc->bg_free_inodes_count) < min_inodes)
+			continue;
+		if (le16_to_cpu(desc->bg_free_blocks_count) < min_blocks)
+			continue;
+		return group;
+	}
+
+fallback:
+	for (i = 0; i < ngroups; i++) {
+		group = (parent_group + i) % ngroups;
+		desc = ext3_get_group_desc (sb, group, &bh);
+		if (!desc || !desc->bg_free_inodes_count)
+			continue;
+		if (le16_to_cpu(desc->bg_free_inodes_count) >= avefreei)
+			return group;
+	}
+
+	if (avefreei) {
+		/*
+		 * The free-inodes counter is approximate, and for really small
+		 * filesystems the above test can fail to find any blockgroups
+		 */
+		avefreei = 0;
+		goto fallback;
+	}
+
+	return -1;
+}
+
+static int find_group_other(struct super_block *sb, struct inode *parent)
+{
+	int parent_group = EXT3_I(parent)->i_block_group;
+	int ngroups = EXT3_SB(sb)->s_groups_count;
+	struct ext3_group_desc *desc;
+	struct buffer_head *bh;
+	int group, i;
+
+	/*
+	 * Try to place the inode in its parent directory
+	 */
+	group = parent_group;
+	desc = ext3_get_group_desc (sb, group, &bh);
+	if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
+			le16_to_cpu(desc->bg_free_blocks_count))
+		return group;
+
+	/*
+	 * We're going to place this inode in a different blockgroup from its
+	 * parent.  We want to cause files in a common directory to all land in
+	 * the same blockgroup.  But we want files which are in a different
+	 * directory which shares a blockgroup with our parent to land in a
+	 * different blockgroup.
+	 *
+	 * So add our directory's i_ino into the starting point for the hash.
+	 */
+	group = (group + parent->i_ino) % ngroups;
+
+	/*
+	 * Use a quadratic hash to find a group with a free inode and some free
+	 * blocks.
+	 */
+	for (i = 1; i < ngroups; i <<= 1) {
+		group += i;
+		if (group >= ngroups)
+			group -= ngroups;
+		desc = ext3_get_group_desc (sb, group, &bh);
+		if (desc && le16_to_cpu(desc->bg_free_inodes_count) &&
+				le16_to_cpu(desc->bg_free_blocks_count))
+			return group;
+	}
+
+	/*
+	 * That failed: try linear search for a free inode, even if that group
+	 * has no free blocks.
+	 */
+	group = parent_group;
+	for (i = 0; i < ngroups; i++) {
+		if (++group >= ngroups)
+			group = 0;
+		desc = ext3_get_group_desc (sb, group, &bh);
+		if (desc && le16_to_cpu(desc->bg_free_inodes_count))
+			return group;
+	}
+
+	return -1;
+}
+
+/*
+ * There are two policies for allocating an inode.  If the new inode is
+ * a directory, then a forward search is made for a block group with both
+ * free space and a low directory-to-inode ratio; if that fails, then of
+ * the groups with above-average free space, that group with the fewest
+ * directories already is chosen.
+ *
+ * For other inodes, search forward from the parent directory's block
+ * group to find a free inode.
+ */
+struct inode *ext3_new_inode(handle_t *handle, struct inode * dir, int mode)
+{
+	struct super_block *sb;
+	struct buffer_head *bitmap_bh = NULL;
+	struct buffer_head *bh2;
+	int group;
+	unsigned long ino = 0;
+	struct inode * inode;
+	struct ext3_group_desc * gdp = NULL;
+	struct ext3_super_block * es;
+	struct ext3_inode_info *ei;
+	struct ext3_sb_info *sbi;
+	int err = 0;
+	struct inode *ret;
+	int i;
+
+	/* Cannot create files in a deleted directory */
+	if (!dir || !dir->i_nlink)
+		return ERR_PTR(-EPERM);
+
+	sb = dir->i_sb;
+	inode = new_inode(sb);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	ei = EXT3_I(inode);
+
+	sbi = EXT3_SB(sb);
+	es = sbi->s_es;
+	if (S_ISDIR(mode)) {
+		if (test_opt (sb, OLDALLOC))
+			group = find_group_dir(sb, dir);
+		else
+			group = find_group_orlov(sb, dir);
+	} else
+		group = find_group_other(sb, dir);
+
+	err = -ENOSPC;
+	if (group == -1)
+		goto out;
+
+	for (i = 0; i < sbi->s_groups_count; i++) {
+		err = -EIO;
+
+		gdp = ext3_get_group_desc(sb, group, &bh2);
+		if (!gdp)
+			goto fail;
+
+		brelse(bitmap_bh);
+		bitmap_bh = read_inode_bitmap(sb, group);
+		if (!bitmap_bh)
+			goto fail;
+
+		ino = 0;
+
+repeat_in_this_group:
+		ino = ext3_find_next_zero_bit((unsigned long *)
+				bitmap_bh->b_data, EXT3_INODES_PER_GROUP(sb), ino);
+		if (ino < EXT3_INODES_PER_GROUP(sb)) {
+
+			BUFFER_TRACE(bitmap_bh, "get_write_access");
+			err = ext3_journal_get_write_access(handle, bitmap_bh);
+			if (err)
+				goto fail;
+
+			if (!ext3_set_bit_atomic(sb_bgl_lock(sbi, group),
+						ino, bitmap_bh->b_data)) {
+				/* we won it */
+				BUFFER_TRACE(bitmap_bh,
+					"call ext3_journal_dirty_metadata");
+				err = ext3_journal_dirty_metadata(handle,
+								bitmap_bh);
+				if (err)
+					goto fail;
+				goto got;
+			}
+			/* we lost it */
+			journal_release_buffer(handle, bitmap_bh);
+
+			if (++ino < EXT3_INODES_PER_GROUP(sb))
+				goto repeat_in_this_group;
+		}
+
+		/*
+		 * This case is possible in concurrent environment.  It is very
+		 * rare.  We cannot repeat the find_group_xxx() call because
+		 * that will simply return the same blockgroup, because the
+		 * group descriptor metadata has not yet been updated.
+		 * So we just go onto the next blockgroup.
+		 */
+		if (++group == sbi->s_groups_count)
+			group = 0;
+	}
+	err = -ENOSPC;
+	goto out;
+
+got:
+	ino += group * EXT3_INODES_PER_GROUP(sb) + 1;
+	if (ino < EXT3_FIRST_INO(sb) || ino > le32_to_cpu(es->s_inodes_count)) {
+		ext3_error (sb, "ext3_new_inode",
+			    "reserved inode or inode > inodes count - "
+			    "block_group = %d, inode=%lu", group, ino);
+		err = -EIO;
+		goto fail;
+	}
+
+	BUFFER_TRACE(bh2, "get_write_access");
+	err = ext3_journal_get_write_access(handle, bh2);
+	if (err) goto fail;
+	spin_lock(sb_bgl_lock(sbi, group));
+	gdp->bg_free_inodes_count =
+		cpu_to_le16(le16_to_cpu(gdp->bg_free_inodes_count) - 1);
+	if (S_ISDIR(mode)) {
+		gdp->bg_used_dirs_count =
+			cpu_to_le16(le16_to_cpu(gdp->bg_used_dirs_count) + 1);
+	}
+	spin_unlock(sb_bgl_lock(sbi, group));
+	BUFFER_TRACE(bh2, "call ext3_journal_dirty_metadata");
+	err = ext3_journal_dirty_metadata(handle, bh2);
+	if (err) goto fail;
+
+	percpu_counter_dec(&sbi->s_freeinodes_counter);
+	if (S_ISDIR(mode))
+		percpu_counter_inc(&sbi->s_dirs_counter);
+	sb->s_dirt = 1;
+
+	inode->i_uid = current->fsuid;
+	if (test_opt (sb, GRPID))
+		inode->i_gid = dir->i_gid;
+	else if (dir->i_mode & S_ISGID) {
+		inode->i_gid = dir->i_gid;
+		if (S_ISDIR(mode))
+			mode |= S_ISGID;
+	} else
+		inode->i_gid = current->fsgid;
+	inode->i_mode = mode;
+
+	inode->i_ino = ino;
+	/* This is the optimal IO size (for stat), not the fs block size */
+	inode->i_blocks = 0;
+	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
+
+	memset(ei->i_data, 0, sizeof(ei->i_data));
+	ei->i_dir_start_lookup = 0;
+	ei->i_disksize = 0;
+
+	ei->i_flags = EXT3_I(dir)->i_flags & ~EXT3_INDEX_FL;
+	if (S_ISLNK(mode))
+		ei->i_flags &= ~(EXT3_IMMUTABLE_FL|EXT3_APPEND_FL);
+	/* dirsync only applies to directories */
+	if (!S_ISDIR(mode))
+		ei->i_flags &= ~EXT3_DIRSYNC_FL;
+#ifdef EXT3_FRAGMENTS
+	ei->i_faddr = 0;
+	ei->i_frag_no = 0;
+	ei->i_frag_size = 0;
+#endif
+	ei->i_file_acl = 0;
+	ei->i_dir_acl = 0;
+	ei->i_dtime = 0;
+	ei->i_block_alloc_info = NULL;
+	ei->i_block_group = group;
+
+	ext3_set_inode_flags(inode);
+	if (IS_DIRSYNC(inode))
+		handle->h_sync = 1;
+	insert_inode_hash(inode);
+	spin_lock(&sbi->s_next_gen_lock);
+	inode->i_generation = sbi->s_next_generation++;
+	spin_unlock(&sbi->s_next_gen_lock);
+
+	ei->i_state = EXT3_STATE_NEW;
+	ei->i_extra_isize =
+		(EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) ?
+		sizeof(struct ext3_inode) - EXT3_GOOD_OLD_INODE_SIZE : 0;
+
+	ret = inode;
+	if(DQUOT_ALLOC_INODE(inode)) {
+		err = -EDQUOT;
+		goto fail_drop;
+	}
+
+	err = ext3_init_acl(handle, inode, dir);
+	if (err)
+		goto fail_free_drop;
+
+	err = ext3_init_security(handle,inode, dir);
+	if (err)
+		goto fail_free_drop;
+
+	err = ext3_mark_inode_dirty(handle, inode);
+	if (err) {
+		ext3_std_error(sb, err);
+		goto fail_free_drop;
+	}
+
+	ext3_debug("allocating inode %lu\n", inode->i_ino);
+	goto really_out;
+fail:
+	ext3_std_error(sb, err);
+out:
+	iput(inode);
+	ret = ERR_PTR(err);
+really_out:
+	brelse(bitmap_bh);
+	return ret;
+
+fail_free_drop:
+	DQUOT_FREE_INODE(inode);
+
+fail_drop:
+	DQUOT_DROP(inode);
+	inode->i_flags |= S_NOQUOTA;
+	inode->i_nlink = 0;
+	iput(inode);
+	brelse(bitmap_bh);
+	return ERR_PTR(err);
+}
+
+/* Verify that we are loading a valid orphan from disk */
+struct inode *ext3_orphan_get(struct super_block *sb, unsigned long ino)
+{
+	unsigned long max_ino = le32_to_cpu(EXT3_SB(sb)->s_es->s_inodes_count);
+	unsigned long block_group;
+	int bit;
+	struct buffer_head *bitmap_bh = NULL;
+	struct inode *inode = NULL;
+
+	/* Error cases - e2fsck has already cleaned up for us */
+	if (ino > max_ino) {
+		ext3_warning(sb, __FUNCTION__,
+			     "bad orphan ino %lu!  e2fsck was run?", ino);
+		goto out;
+	}
+
+	block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
+	bit = (ino - 1) % EXT3_INODES_PER_GROUP(sb);
+	bitmap_bh = read_inode_bitmap(sb, block_group);
+	if (!bitmap_bh) {
+		ext3_warning(sb, __FUNCTION__,
+			     "inode bitmap error for orphan %lu", ino);
+		goto out;
+	}
+
+	/* Having the inode bit set should be a 100% indicator that this
+	 * is a valid orphan (no e2fsck run on fs).  Orphans also include
+	 * inodes that were being truncated, so we can't check i_nlink==0.
+	 */
+	if (!ext3_test_bit(bit, bitmap_bh->b_data) ||
+			!(inode = iget(sb, ino)) || is_bad_inode(inode) ||
+			NEXT_ORPHAN(inode) > max_ino) {
+		ext3_warning(sb, __FUNCTION__,
+			     "bad orphan inode %lu!  e2fsck was run?", ino);
+		printk(KERN_NOTICE "ext3_test_bit(bit=%d, block=%llu) = %d\n",
+		       bit, (unsigned long long)bitmap_bh->b_blocknr,
+		       ext3_test_bit(bit, bitmap_bh->b_data));
+		printk(KERN_NOTICE "inode=%p\n", inode);
+		if (inode) {
+			printk(KERN_NOTICE "is_bad_inode(inode)=%d\n",
+			       is_bad_inode(inode));
+			printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
+			       NEXT_ORPHAN(inode));
+			printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
+		}
+		/* Avoid freeing blocks if we got a bad deleted inode */
+		if (inode && inode->i_nlink == 0)
+			inode->i_blocks = 0;
+		iput(inode);
+		inode = NULL;
+	}
+out:
+	brelse(bitmap_bh);
+	return inode;
+}
+
+unsigned long ext3_count_free_inodes (struct super_block * sb)
+{
+	unsigned long desc_count;
+	struct ext3_group_desc *gdp;
+	int i;
+#ifdef EXT3FS_DEBUG
+	struct ext3_super_block *es;
+	unsigned long bitmap_count, x;
+	struct buffer_head *bitmap_bh = NULL;
+
+	es = EXT3_SB(sb)->s_es;
+	desc_count = 0;
+	bitmap_count = 0;
+	gdp = NULL;
+	for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
+		gdp = ext3_get_group_desc (sb, i, NULL);
+		if (!gdp)
+			continue;
+		desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
+		brelse(bitmap_bh);
+		bitmap_bh = read_inode_bitmap(sb, i);
+		if (!bitmap_bh)
+			continue;
+
+		x = ext3_count_free(bitmap_bh, EXT3_INODES_PER_GROUP(sb) / 8);
+		printk("group %d: stored = %d, counted = %lu\n",
+			i, le16_to_cpu(gdp->bg_free_inodes_count), x);
+		bitmap_count += x;
+	}
+	brelse(bitmap_bh);
+	printk("ext3_count_free_inodes: stored = %u, computed = %lu, %lu\n",
+		le32_to_cpu(es->s_free_inodes_count), desc_count, bitmap_count);
+	return desc_count;
+#else
+	desc_count = 0;
+	for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
+		gdp = ext3_get_group_desc (sb, i, NULL);
+		if (!gdp)
+			continue;
+		desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
+		cond_resched();
+	}
+	return desc_count;
+#endif
+}
+
+/* Called at mount-time, super-block is locked */
+unsigned long ext3_count_dirs (struct super_block * sb)
+{
+	unsigned long count = 0;
+	int i;
+
+	for (i = 0; i < EXT3_SB(sb)->s_groups_count; i++) {
+		struct ext3_group_desc *gdp = ext3_get_group_desc (sb, i, NULL);
+		if (!gdp)
+			continue;
+		count += le16_to_cpu(gdp->bg_used_dirs_count);
+	}
+	return count;
+}
+

fs/ext4/inode.c

+/*
+ *  linux/fs/ext3/inode.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/inode.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  Goal-directed block allocation by Stephen Tweedie
+ *	(sct@redhat.com), 1993, 1998
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ *  64-bit file support on 64-bit platforms by Jakub Jelinek
+ *	(jj@sunsite.ms.mff.cuni.cz)
+ *
+ *  Assorted race fixes, rewrite of ext3_get_block() by Al Viro, 2000
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/time.h>
+#include <linux/ext3_jbd.h>
+#include <linux/jbd.h>
+#include <linux/smp_lock.h>
+#include <linux/highuid.h>
+#include <linux/pagemap.h>
+#include <linux/quotaops.h>
+#include <linux/string.h>
+#include <linux/buffer_head.h>
+#include <linux/writeback.h>
+#include <linux/mpage.h>
+#include <linux/uio.h>
+#include <linux/bio.h>
+#include "xattr.h"
+#include "acl.h"
+
+static int ext3_writepage_trans_blocks(struct inode *inode);
+
+/*
+ * Test whether an inode is a fast symlink.
+ */
+static int ext3_inode_is_fast_symlink(struct inode *inode)
+{
+	int ea_blocks = EXT3_I(inode)->i_file_acl ?
+		(inode->i_sb->s_blocksize >> 9) : 0;
+
+	return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
+}
+
+/*
+ * The ext3 forget function must perform a revoke if we are freeing data
+ * which has been journaled.  Metadata (eg. indirect blocks) must be
+ * revoked in all cases.
+ *
+ * "bh" may be NULL: a metadata block may have been freed from memory
+ * but there may still be a record of it in the journal, and that record
+ * still needs to be revoked.
+ */
+int ext3_forget(handle_t *handle, int is_metadata, struct inode *inode,
+			struct buffer_head *bh, ext3_fsblk_t blocknr)
+{
+	int err;
+
+	might_sleep();
+
+	BUFFER_TRACE(bh, "enter");
+
+	jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
+		  "data mode %lx\n",
+		  bh, is_metadata, inode->i_mode,
+		  test_opt(inode->i_sb, DATA_FLAGS));
+
+	/* Never use the revoke function if we are doing full data
+	 * journaling: there is no need to, and a V1 superblock won't
+	 * support it.  Otherwise, only skip the revoke on un-journaled
+	 * data blocks. */
+
+	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT3_MOUNT_JOURNAL_DATA ||
+	    (!is_metadata && !ext3_should_journal_data(inode))) {
+		if (bh) {
+			BUFFER_TRACE(bh, "call journal_forget");
+			return ext3_journal_forget(handle, bh);
+		}
+		return 0;
+	}
+
+	/*
+	 * data!=journal && (is_metadata || should_journal_data(inode))
+	 */
+	BUFFER_TRACE(bh, "call ext3_journal_revoke");
+	err = ext3_journal_revoke(handle, blocknr, bh);
+	if (err)
+		ext3_abort(inode->i_sb, __FUNCTION__,
+			   "error %d when attempting revoke", err);
+	BUFFER_TRACE(bh, "exit");
+	return err;
+}
+
+/*
+ * Work out how many blocks we need to proceed with the next chunk of a
+ * truncate transaction.
+ */
+static unsigned long blocks_for_truncate(struct inode *inode)
+{
+	unsigned long needed;
+
+	needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
+
+	/* Give ourselves just enough room to cope with inodes in which
+	 * i_blocks is corrupt: we've seen disk corruptions in the past
+	 * which resulted in random data in an inode which looked enough
+	 * like a regular file for ext3 to try to delete it.  Things
+	 * will go a bit crazy if that happens, but at least we should
+	 * try not to panic the whole kernel. */
+	if (needed < 2)
+		needed = 2;
+
+	/* But we need to bound the transaction so we don't overflow the
+	 * journal. */
+	if (needed > EXT3_MAX_TRANS_DATA)
+		needed = EXT3_MAX_TRANS_DATA;
+
+	return EXT3_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
+}
+
+/*
+ * Truncate transactions can be complex and absolutely huge.  So we need to
+ * be able to restart the transaction at a conventient checkpoint to make
+ * sure we don't overflow the journal.
+ *
+ * start_transaction gets us a new handle for a truncate transaction,
+ * and extend_transaction tries to extend the existing one a bit.  If
+ * extend fails, we need to propagate the failure up and restart the
+ * transaction in the top-level truncate loop. --sct
+ */
+static handle_t *start_transaction(struct inode *inode)
+{
+	handle_t *result;
+
+	result = ext3_journal_start(inode, blocks_for_truncate(inode));
+	if (!IS_ERR(result))
+		return result;
+
+	ext3_std_error(inode->i_sb, PTR_ERR(result));
+	return result;
+}
+
+/*
+ * Try to extend this transaction for the purposes of truncation.
+ *
+ * Returns 0 if we managed to create more room.  If we can't create more
+ * room, and the transaction must be restarted we return 1.
+ */
+static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
+{
+	if (handle->h_buffer_credits > EXT3_RESERVE_TRANS_BLOCKS)
+		return 0;
+	if (!ext3_journal_extend(handle, blocks_for_truncate(inode)))
+		return 0;
+	return 1;
+}
+
+/*
+ * Restart the transaction associated with *handle.  This does a commit,
+ * so before we call here everything must be consistently dirtied against
+ * this transaction.
+ */
+static int ext3_journal_test_restart(handle_t *handle, struct inode *inode)
+{
+	jbd_debug(2, "restarting handle %p\n", handle);
+	return ext3_journal_restart(handle, blocks_for_truncate(inode));
+}
+
+/*
+ * Called at the last iput() if i_nlink is zero.
+ */
+void ext3_delete_inode (struct inode * inode)
+{
+	handle_t *handle;
+
+	truncate_inode_pages(&inode->i_data, 0);
+
+	if (is_bad_inode(inode))
+		goto no_delete;
+
+	handle = start_transaction(inode);
+	if (IS_ERR(handle)) {
+		/*
+		 * If we're going to skip the normal cleanup, we still need to
+		 * make sure that the in-core orphan linked list is properly
+		 * cleaned up.
+		 */
+		ext3_orphan_del(NULL, inode);
+		goto no_delete;
+	}
+
+	if (IS_SYNC(inode))
+		handle->h_sync = 1;
+	inode->i_size = 0;
+	if (inode->i_blocks)
+		ext3_truncate(inode);
+	/*
+	 * Kill off the orphan record which ext3_truncate created.
+	 * AKPM: I think this can be inside the above `if'.
+	 * Note that ext3_orphan_del() has to be able to cope with the
+	 * deletion of a non-existent orphan - this is because we don't
+	 * know if ext3_truncate() actually created an orphan record.
+	 * (Well, we could do this if we need to, but heck - it works)
+	 */
+	ext3_orphan_del(handle, inode);
+	EXT3_I(inode)->i_dtime	= get_seconds();
+
+	/*
+	 * One subtle ordering requirement: if anything has gone wrong
+	 * (transaction abort, IO errors, whatever), then we can still
+	 * do these next steps (the fs will already have been marked as
+	 * having errors), but we can't free the inode if the mark_dirty
+	 * fails.
+	 */
+	if (ext3_mark_inode_dirty(handle, inode))
+		/* If that failed, just do the required in-core inode clear. */
+		clear_inode(inode);
+	else
+		ext3_free_inode(handle, inode);
+	ext3_journal_stop(handle);
+	return;
+no_delete:
+	clear_inode(inode);	/* We must guarantee clearing of inode... */
+}
+
+typedef struct {
+	__le32	*p;
+	__le32	key;
+	struct buffer_head *bh;
+} Indirect;
+
+static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
+{
+	p->key = *(p->p = v);
+	p->bh = bh;
+}
+
+static int verify_chain(Indirect *from, Indirect *to)
+{
+	while (from <= to && from->key == *from->p)
+		from++;
+	return (from > to);
+}
+
+/**
+ *	ext3_block_to_path - parse the block number into array of offsets
+ *	@inode: inode in question (we are only interested in its superblock)
+ *	@i_block: block number to be parsed
+ *	@offsets: array to store the offsets in
+ *      @boundary: set this non-zero if the referred-to block is likely to be
+ *             followed (on disk) by an indirect block.
+ *
+ *	To store the locations of file's data ext3 uses a data structure common
+ *	for UNIX filesystems - tree of pointers anchored in the inode, with
+ *	data blocks at leaves and indirect blocks in intermediate nodes.
+ *	This function translates the block number into path in that tree -
+ *	return value is the path length and @offsets[n] is the offset of
+ *	pointer to (n+1)th node in the nth one. If @block is out of range
+ *	(negative or too large) warning is printed and zero returned.
+ *
+ *	Note: function doesn't find node addresses, so no IO is needed. All
+ *	we need to know is the capacity of indirect blocks (taken from the
+ *	inode->i_sb).
+ */
+
+/*
+ * Portability note: the last comparison (check that we fit into triple
+ * indirect block) is spelled differently, because otherwise on an
+ * architecture with 32-bit longs and 8Kb pages we might get into trouble
+ * if our filesystem had 8Kb blocks. We might use long long, but that would
+ * kill us on x86. Oh, well, at least the sign propagation does not matter -
+ * i_block would have to be negative in the very beginning, so we would not
+ * get there at all.
+ */
+
+static int ext3_block_to_path(struct inode *inode,
+			long i_block, int offsets[4], int *boundary)
+{
+	int ptrs = EXT3_ADDR_PER_BLOCK(inode->i_sb);
+	int ptrs_bits = EXT3_ADDR_PER_BLOCK_BITS(inode->i_sb);
+	const long direct_blocks = EXT3_NDIR_BLOCKS,
+		indirect_blocks = ptrs,
+		double_blocks = (1 << (ptrs_bits * 2));
+	int n = 0;
+	int final = 0;
+
+	if (i_block < 0) {
+		ext3_warning (inode->i_sb, "ext3_block_to_path", "block < 0");
+	} else if (i_block < direct_blocks) {
+		offsets[n++] = i_block;
+		final = direct_blocks;
+	} else if ( (i_block -= direct_blocks) < indirect_blocks) {
+		offsets[n++] = EXT3_IND_BLOCK;
+		offsets[n++] = i_block;
+		final = ptrs;
+	} else if ((i_block -= indirect_blocks) < double_blocks) {
+		offsets[n++] = EXT3_DIND_BLOCK;
+		offsets[n++] = i_block >> ptrs_bits;
+		offsets[n++] = i_block & (ptrs - 1);
+		final = ptrs;
+	} else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
+		offsets[n++] = EXT3_TIND_BLOCK;
+		offsets[n++] = i_block >> (ptrs_bits * 2);
+		offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
+		offsets[n++] = i_block & (ptrs - 1);
+		final = ptrs;
+	} else {
+		ext3_warning(inode->i_sb, "ext3_block_to_path", "block > big");
+	}
+	if (boundary)
+		*boundary = final - 1 - (i_block & (ptrs - 1));
+	return n;
+}
+
+/**
+ *	ext3_get_branch - read the chain of indirect blocks leading to data
+ *	@inode: inode in question
+ *	@depth: depth of the chain (1 - direct pointer, etc.)
+ *	@offsets: offsets of pointers in inode/indirect blocks
+ *	@chain: place to store the result
+ *	@err: here we store the error value
+ *
+ *	Function fills the array of triples <key, p, bh> and returns %NULL
+ *	if everything went OK or the pointer to the last filled triple
+ *	(incomplete one) otherwise. Upon the return chain[i].key contains
+ *	the number of (i+1)-th block in the chain (as it is stored in memory,
+ *	i.e. little-endian 32-bit), chain[i].p contains the address of that
+ *	number (it points into struct inode for i==0 and into the bh->b_data
+ *	for i>0) and chain[i].bh points to the buffer_head of i-th indirect
+ *	block for i>0 and NULL for i==0. In other words, it holds the block
+ *	numbers of the chain, addresses they were taken from (and where we can
+ *	verify that chain did not change) and buffer_heads hosting these
+ *	numbers.
+ *
+ *	Function stops when it stumbles upon zero pointer (absent block)
+ *		(pointer to last triple returned, *@err == 0)
+ *	or when it gets an IO error reading an indirect block
+ *		(ditto, *@err == -EIO)
+ *	or when it notices that chain had been changed while it was reading
+ *		(ditto, *@err == -EAGAIN)
+ *	or when it reads all @depth-1 indirect blocks successfully and finds
+ *	the whole chain, all way to the data (returns %NULL, *err == 0).
+ */
+static Indirect *ext3_get_branch(struct inode *inode, int depth, int *offsets,
+				 Indirect chain[4], int *err)
+{
+	struct super_block *sb = inode->i_sb;
+	Indirect *p = chain;
+	struct buffer_head *bh;
+
+	*err = 0;
+	/* i_data is not going away, no lock needed */
+	add_chain (chain, NULL, EXT3_I(inode)->i_data + *offsets);
+	if (!p->key)
+		goto no_block;
+	while (--depth) {
+		bh = sb_bread(sb, le32_to_cpu(p->key));
+		if (!bh)
+			goto failure;
+		/* Reader: pointers */
+		if (!verify_chain(chain, p))
+			goto changed;
+		add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
+		/* Reader: end */
+		if (!p->key)
+			goto no_block;
+	}
+	return NULL;
+
+changed:
+	brelse(bh);
+	*err = -EAGAIN;
+	goto no_block;
+failure:
+	*err = -EIO;
+no_block:
+	return p;
+}
+
+/**
+ *	ext3_find_near - find a place for allocation with sufficient locality
+ *	@inode: owner
+ *	@ind: descriptor of indirect block.
+ *
+ *	This function returns the prefered place for block allocation.
+ *	It is used when heuristic for sequential allocation fails.
+ *	Rules are:
+ *	  + if there is a block to the left of our position - allocate near it.
+ *	  + if pointer will live in indirect block - allocate near that block.
+ *	  + if pointer will live in inode - allocate in the same
+ *	    cylinder group.
+ *
+ * In the latter case we colour the starting block by the callers PID to
+ * prevent it from clashing with concurrent allocations for a different inode
+ * in the same block group.   The PID is used here so that functionally related
+ * files will be close-by on-disk.
+ *
+ *	Caller must make sure that @ind is valid and will stay that way.
+ */
+static ext3_fsblk_t ext3_find_near(struct inode *inode, Indirect *ind)
+{
+	struct ext3_inode_info *ei = EXT3_I(inode);
+	__le32 *start = ind->bh ? (__le32*) ind->bh->b_data : ei->i_data;
+	__le32 *p;
+	ext3_fsblk_t bg_start;
+	ext3_grpblk_t colour;
+
+	/* Try to find previous block */
+	for (p = ind->p - 1; p >= start; p--) {
+		if (*p)
+			return le32_to_cpu(*p);
+	}
+
+	/* No such thing, so let's try location of indirect block */
+	if (ind->bh)
+		return ind->bh->b_blocknr;
+
+	/*
+	 * It is going to be referred to from the inode itself? OK, just put it
+	 * into the same cylinder group then.
+	 */
+	bg_start = ext3_group_first_block_no(inode->i_sb, ei->i_block_group);
+	colour = (current->pid % 16) *
+			(EXT3_BLOCKS_PER_GROUP(inode->i_sb) / 16);
+	return bg_start + colour;
+}
+
+/**
+ *	ext3_find_goal - find a prefered place for allocation.
+ *	@inode: owner
+ *	@block:  block we want
+ *	@chain:  chain of indirect blocks
+ *	@partial: pointer to the last triple within a chain
+ *	@goal:	place to store the result.
+ *
+ *	Normally this function find the prefered place for block allocation,
+ *	stores it in *@goal and returns zero.
+ */
+
+static ext3_fsblk_t ext3_find_goal(struct inode *inode, long block,
+		Indirect chain[4], Indirect *partial)
+{
+	struct ext3_block_alloc_info *block_i;
+
+	block_i =  EXT3_I(inode)->i_block_alloc_info;
+
+	/*
+	 * try the heuristic for sequential allocation,
+	 * failing that at least try to get decent locality.
+	 */
+	if (block_i && (block == block_i->last_alloc_logical_block + 1)
+		&& (block_i->last_alloc_physical_block != 0)) {
+		return block_i->last_alloc_physical_block + 1;
+	}
+
+	return ext3_find_near(inode, partial);
+}
+
+/**
+ *	ext3_blks_to_allocate: Look up the block map and count the number
+ *	of direct blocks need to be allocated for the given branch.
+ *
+ *	@branch: chain of indirect blocks
+ *	@k: number of blocks need for indirect blocks
+ *	@blks: number of data blocks to be mapped.
+ *	@blocks_to_boundary:  the offset in the indirect block
+ *
+ *	return the total number of blocks to be allocate, including the
+ *	direct and indirect blocks.
+ */
+static int ext3_blks_to_allocate(Indirect *branch, int k, unsigned long blks,
+		int blocks_to_boundary)
+{
+	unsigned long count = 0;
+
+	/*
+	 * Simple case, [t,d]Indirect block(s) has not allocated yet
+	 * then it's clear blocks on that path have not allocated
+	 */
+	if (k > 0) {
+		/* right now we don't handle cross boundary allocation */
+		if (blks < blocks_to_boundary + 1)
+			count += blks;
+		else
+			count += blocks_to_boundary + 1;
+		return count;
+	}
+
+	count++;
+	while (count < blks && count <= blocks_to_boundary &&
+		le32_to_cpu(*(branch[0].p + count)) == 0) {
+		count++;
+	}
+	return count;
+}
+
+/**
+ *	ext3_alloc_blocks: multiple allocate blocks needed for a branch
+ *	@indirect_blks: the number of blocks need to allocate for indirect
+ *			blocks
+ *
+ *	@new_blocks: on return it will store the new block numbers for
+ *	the indirect blocks(if needed) and the first direct block,
+ *	@blks:	on return it will store the total number of allocated
+ *		direct blocks
+ */
+static int ext3_alloc_blocks(handle_t *handle, struct inode *inode,
+			ext3_fsblk_t goal, int indirect_blks, int blks,
+			ext3_fsblk_t new_blocks[4], int *err)
+{
+	int target, i;
+	unsigned long count = 0;
+	int index = 0;
+	ext3_fsblk_t current_block = 0;
+	int ret = 0;
+
+	/*
+	 * Here we try to allocate the requested multiple blocks at once,
+	 * on a best-effort basis.
+	 * To build a branch, we should allocate blocks for
+	 * the indirect blocks(if not allocated yet), and at least
+	 * the first direct block of this branch.  That's the
+	 * minimum number of blocks need to allocate(required)
+	 */
+	target = blks + indirect_blks;
+
+	while (1) {
+		count = target;
+		/* allocating blocks for indirect blocks and direct blocks */
+		current_block = ext3_new_blocks(handle,inode,goal,&count,err);
+		if (*err)
+			goto failed_out;
+
+		target -= count;
+		/* allocate blocks for indirect blocks */
+		while (index < indirect_blks && count) {
+			new_blocks[index++] = current_block++;
+			count--;
+		}
+
+		if (count > 0)
+			break;
+	}
+
+	/* save the new block number for the first direct block */
+	new_blocks[index] = current_block;
+
+	/* total number of blocks allocated for direct blocks */
+	ret = count;
+	*err = 0;
+	return ret;
+failed_out:
+	for (i = 0; i <index; i++)
+		ext3_free_blocks(handle, inode, new_blocks[i], 1);
+	return ret;
+}
+
+/**
+ *	ext3_alloc_branch - allocate and set up a chain of blocks.
+ *	@inode: owner
+ *	@indirect_blks: number of allocated indirect blocks
+ *	@blks: number of allocated direct blocks
+ *	@offsets: offsets (in the blocks) to store the pointers to next.
+ *	@branch: place to store the chain in.
+ *
+ *	This function allocates blocks, zeroes out all but the last one,
+ *	links them into chain and (if we are synchronous) writes them to disk.
+ *	In other words, it prepares a branch that can be spliced onto the
+ *	inode. It stores the information about that chain in the branch[], in
+ *	the same format as ext3_get_branch() would do. We are calling it after
+ *	we had read the existing part of chain and partial points to the last
+ *	triple of that (one with zero ->key). Upon the exit we have the same
+ *	picture as after the successful ext3_get_block(), except that in one
+ *	place chain is disconnected - *branch->p is still zero (we did not
+ *	set the last link), but branch->key contains the number that should
+ *	be placed into *branch->p to fill that gap.
+ *
+ *	If allocation fails we free all blocks we've allocated (and forget
+ *	their buffer_heads) and return the error value the from failed
+ *	ext3_alloc_block() (normally -ENOSPC). Otherwise we set the chain
+ *	as described above and return 0.
+ */
+static int ext3_alloc_branch(handle_t *handle, struct inode *inode,
+			int indirect_blks, int *blks, ext3_fsblk_t goal,
+			int *offsets, Indirect *branch)
+{
+	int blocksize = inode->i_sb->s_blocksize;
+	int i, n = 0;
+	int err = 0;
+	struct buffer_head *bh;
+	int num;
+	ext3_fsblk_t new_blocks[4];
+	ext3_fsblk_t current_block;
+
+	num = ext3_alloc_blocks(handle, inode, goal, indirect_blks,
+				*blks, new_blocks, &err);
+	if (err)
+		return err;
+
+	branch[0].key = cpu_to_le32(new_blocks[0]);
+	/*
+	 * metadata blocks and data blocks are allocated.
+	 */
+	for (n = 1; n <= indirect_blks;  n++) {
+		/*
+		 * Get buffer_head for parent block, zero it out
+		 * and set the pointer to new one, then send
+		 * parent to disk.
+		 */
+		bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
+		branch[n].bh = bh;
+		lock_buffer(bh);
+		BUFFER_TRACE(bh, "call get_create_access");
+		err = ext3_journal_get_create_access(handle, bh);
+		if (err) {
+			unlock_buffer(bh);
+			brelse(bh);
+			goto failed;
+		}
+
+		memset(bh->b_data, 0, blocksize);
+		branch[n].p = (__le32 *) bh->b_data + offsets[n];
+		branch[n].key = cpu_to_le32(new_blocks[n]);
+		*branch[n].p = branch[n].key;
+		if ( n == indirect_blks) {
+			current_block = new_blocks[n];
+			/*
+			 * End of chain, update the last new metablock of
+			 * the chain to point to the new allocated
+			 * data blocks numbers
+			 */
+			for (i=1; i < num; i++)
+				*(branch[n].p + i) = cpu_to_le32(++current_block);
+		}
+		BUFFER_TRACE(bh, "marking uptodate");
+		set_buffer_uptodate(bh);
+		unlock_buffer(bh);
+
+		BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
+		err = ext3_journal_dirty_metadata(handle, bh);
+		if (err)
+			goto failed;
+	}
+	*blks = num;
+	return err;
+failed:
+	/* Allocation failed, free what we already allocated */
+	for (i = 1; i <= n ; i++) {
+		BUFFER_TRACE(branch[i].bh, "call journal_forget");
+		ext3_journal_forget(handle, branch[i].bh);
+	}
+	for (i = 0; i <indirect_blks; i++)
+		ext3_free_blocks(handle, inode, new_blocks[i], 1);
+
+	ext3_free_blocks(handle, inode, new_blocks[i], num);
+
+	return err;
+}
+
+/**
+ * ext3_splice_branch - splice the allocated branch onto inode.
+ * @inode: owner
+ * @block: (logical) number of block we are adding
+ * @chain: chain of indirect blocks (with a missing link - see
+ *	ext3_alloc_branch)
+ * @where: location of missing link
+ * @num:   number of indirect blocks we are adding
+ * @blks:  number of direct blocks we are adding
+ *
+ * This function fills the missing link and does all housekeeping needed in
+ * inode (->i_blocks, etc.). In case of success we end up with the full
+ * chain to new block and return 0.
+ */
+static int ext3_splice_branch(handle_t *handle, struct inode *inode,
+			long block, Indirect *where, int num, int blks)
+{
+	int i;
+	int err = 0;
+	struct ext3_block_alloc_info *block_i;
+	ext3_fsblk_t current_block;
+
+	block_i = EXT3_I(inode)->i_block_alloc_info;
+	/*
+	 * If we're splicing into a [td]indirect block (as opposed to the
+	 * inode) then we need to get write access to the [td]indirect block
+	 * before the splice.
+	 */
+	if (where->bh) {
+		BUFFER_TRACE(where->bh, "get_write_access");
+		err = ext3_journal_get_write_access(handle, where->bh);
+		if (err)
+			goto err_out;
+	}
+	/* That's it */
+
+	*where->p = where->key;
+
+	/*
+	 * Update the host buffer_head or inode to point to more just allocated
+	 * direct blocks blocks
+	 */
+	if (num == 0 && blks > 1) {
+		current_block = le32_to_cpu(where->key) + 1;
+		for (i = 1; i < blks; i++)
+			*(where->p + i ) = cpu_to_le32(current_block++);
+	}
+
+	/*
+	 * update the most recently allocated logical & physical block
+	 * in i_block_alloc_info, to assist find the proper goal block for next
+	 * allocation
+	 */
+	if (block_i) {
+		block_i->last_alloc_logical_block = block + blks - 1;
+		block_i->last_alloc_physical_block =
+				le32_to_cpu(where[num].key) + blks - 1;
+	}
+
+	/* We are done with atomic stuff, now do the rest of housekeeping */
+
+	inode->i_ctime = CURRENT_TIME_SEC;
+	ext3_mark_inode_dirty(handle, inode);
+
+	/* had we spliced it onto indirect block? */
+	if (where->bh) {
+		/*
+		 * If we spliced it onto an indirect block, we haven't
+		 * altered the inode.  Note however that if it is being spliced
+		 * onto an indirect block at the very end of the file (the
+		 * file is growing) then we *will* alter the inode to reflect
+		 * the new i_size.  But that is not done here - it is done in
+		 * generic_commit_write->__mark_inode_dirty->ext3_dirty_inode.
+		 */
+		jbd_debug(5, "splicing indirect only\n");
+		BUFFER_TRACE(where->bh, "call ext3_journal_dirty_metadata");
+		err = ext3_journal_dirty_metadata(handle, where->bh);
+		if (err)
+			goto err_out;
+	} else {
+		/*
+		 * OK, we spliced it into the inode itself on a direct block.
+		 * Inode was dirtied above.
+		 */
+		jbd_debug(5, "splicing direct\n");
+	}
+	return err;
+
+err_out:
+	for (i = 1; i <= num; i++) {
+		BUFFER_TRACE(where[i].bh, "call journal_forget");
+		ext3_journal_forget(handle, where[i].bh);
+		ext3_free_blocks(handle,inode,le32_to_cpu(where[i-1].key),1);
+	}
+	ext3_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks);
+
+	return err;
+}
+
+/*
+ * Allocation strategy is simple: if we have to allocate something, we will
+ * have to go the whole way to leaf. So let's do it before attaching anything
+ * to tree, set linkage between the newborn blocks, write them if sync is
+ * required, recheck the path, free and repeat if check fails, otherwise
+ * set the last missing link (that will protect us from any truncate-generated
+ * removals - all blocks on the path are immune now) and possibly force the
+ * write on the parent block.
+ * That has a nice additional property: no special recovery from the failed
+ * allocations is needed - we simply release blocks and do not touch anything
+ * reachable from inode.
+ *
+ * `handle' can be NULL if create == 0.
+ *
+ * The BKL may not be held on entry here.  Be sure to take it early.
+ * return > 0, # of blocks mapped or allocated.
+ * return = 0, if plain lookup failed.
+ * return < 0, error case.
+ */
+int ext3_get_blocks_handle(handle_t *handle, struct inode *inode,
+		sector_t iblock, unsigned long maxblocks,
+		struct buffer_head *bh_result,
+		int create, int extend_disksize)
+{
+	int err = -EIO;
+	int offsets[4];
+	Indirect chain[4];
+	Indirect *partial;
+	ext3_fsblk_t goal;
+	int indirect_blks;
+	int blocks_to_boundary = 0;
+	int depth;
+	struct ext3_inode_info *ei = EXT3_I(inode);
+	int count = 0;
+	ext3_fsblk_t first_block = 0;
+
+
+	J_ASSERT(handle != NULL || create == 0);
+	depth = ext3_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
+
+	if (depth == 0)
+		goto out;
+
+	partial = ext3_get_branch(inode, depth, offsets, chain, &err);
+
+	/* Simplest case - block found, no allocation needed */
+	if (!partial) {
+		first_block = le32_to_cpu(chain[depth - 1].key);
+		clear_buffer_new(bh_result);
+		count++;
+		/*map more blocks*/
+		while (count < maxblocks && count <= blocks_to_boundary) {
+			ext3_fsblk_t blk;
+
+			if (!verify_chain(chain, partial)) {
+				/*
+				 * Indirect block might be removed by
+				 * truncate while we were reading it.
+				 * Handling of that case: forget what we've
+				 * got now. Flag the err as EAGAIN, so it
+				 * will reread.
+				 */
+				err = -EAGAIN;
+				count = 0;
+				break;
+			}
+			blk = le32_to_cpu(*(chain[depth-1].p + count));
+
+			if (blk == first_block + count)
+				count++;
+			else
+				break;
+		}
+		if (err != -EAGAIN)
+			goto got_it;
+	}
+
+	/* Next simple case - plain lookup or failed read of indirect block */
+	if (!create || err == -EIO)
+		goto cleanup;
+
+	mutex_lock(&ei->truncate_mutex);
+
+	/*
+	 * If the indirect block is missing while we are reading
+	 * the chain(ext3_get_branch() returns -EAGAIN err), or
+	 * if the chain has been changed after we grab the semaphore,
+	 * (either because another process truncated this branch, or
+	 * another get_block allocated this branch) re-grab the chain to see if
+	 * the request block has been allocated or not.
+	 *
+	 * Since we already block the truncate/other get_block
+	 * at this point, we will have the current copy of the chain when we
+	 * splice the branch into the tree.
+	 */
+	if (err == -EAGAIN || !verify_chain(chain, partial)) {
+		while (partial > chain) {
+			brelse(partial->bh);
+			partial--;
+		}
+		partial = ext3_get_branch(inode, depth, offsets, chain, &err);
+		if (!partial) {
+			count++;
+			mutex_unlock(&ei->truncate_mutex);
+			if (err)
+				goto cleanup;
+			clear_buffer_new(bh_result);
+			goto got_it;
+		}
+	}
+
+	/*
+	 * Okay, we need to do block allocation.  Lazily initialize the block
+	 * allocation info here if necessary
+	*/
+	if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
+		ext3_init_block_alloc_info(inode);
+
+	goal = ext3_find_goal(inode, iblock, chain, partial);
+
+	/* the number of blocks need to allocate for [d,t]indirect blocks */
+	indirect_blks = (chain + depth) - partial - 1;
+
+	/*
+	 * Next look up the indirect map to count the totoal number of
+	 * direct blocks to allocate for this branch.
+	 */
+	count = ext3_blks_to_allocate(partial, indirect_blks,
+					maxblocks, blocks_to_boundary);
+	/*
+	 * Block out ext3_truncate while we alter the tree
+	 */
+	err = ext3_alloc_branch(handle, inode, indirect_blks, &count, goal,
+				offsets + (partial - chain), partial);
+
+	/*
+	 * The ext3_splice_branch call will free and forget any buffers
+	 * on the new chain if there is a failure, but that risks using
+	 * up transaction credits, especially for bitmaps where the
+	 * credits cannot be returned.  Can we handle this somehow?  We
+	 * may need to return -EAGAIN upwards in the worst case.  --sct
+	 */
+	if (!err)
+		err = ext3_splice_branch(handle, inode, iblock,
+					partial, indirect_blks, count);
+	/*
+	 * i_disksize growing is protected by truncate_mutex.  Don't forget to
+	 * protect it if you're about to implement concurrent
+	 * ext3_get_block() -bzzz
+	*/
+	if (!err && extend_disksize && inode->i_size > ei->i_disksize)
+		ei->i_disksize = inode->i_size;
+	mutex_unlock(&ei->truncate_mutex);
+	if (err)
+		goto cleanup;
+
+	set_buffer_new(bh_result);
+got_it:
+	map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
+	if (count > blocks_to_boundary)
+		set_buffer_boundary(bh_result);
+	err = count;
+	/* Clean up and exit */
+	partial = chain + depth - 1;	/* the whole chain */
+cleanup:
+	while (partial > chain) {
+		BUFFER_TRACE(partial->bh, "call brelse");
+		brelse(partial->bh);
+		partial--;
+	}
+	BUFFER_TRACE(bh_result, "returned");
+out:
+	return err;
+}
+
+#define DIO_CREDITS (EXT3_RESERVE_TRANS_BLOCKS + 32)
+
+static int ext3_get_block(struct inode *inode, sector_t iblock,
+			struct buffer_head *bh_result, int create)
+{
+	handle_t *handle = journal_current_handle();
+	int ret = 0;
+	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
+
+	if (!create)
+		goto get_block;		/* A read */
+
+	if (max_blocks == 1)
+		goto get_block;		/* A single block get */
+
+	if (handle->h_transaction->t_state == T_LOCKED) {
+		/*
+		 * Huge direct-io writes can hold off commits for long
+		 * periods of time.  Let this commit run.
+		 */
+		ext3_journal_stop(handle);
+		handle = ext3_journal_start(inode, DIO_CREDITS);
+		if (IS_ERR(handle))
+			ret = PTR_ERR(handle);
+		goto get_block;
+	}
+
+	if (handle->h_buffer_credits <= EXT3_RESERVE_TRANS_BLOCKS) {
+		/*
+		 * Getting low on buffer credits...
+		 */
+		ret = ext3_journal_extend(handle, DIO_CREDITS);
+		if (ret > 0) {
+			/*
+			 * Couldn't extend the transaction.  Start a new one.
+			 */
+			ret = ext3_journal_restart(handle, DIO_CREDITS);
+		}
+	}
+
+get_block:
+	if (ret == 0) {
+		ret = ext3_get_blocks_handle(handle, inode, iblock,
+					max_blocks, bh_result, create, 0);
+		if (ret > 0) {
+			bh_result->b_size = (ret << inode->i_blkbits);
+			ret = 0;
+		}
+	}
+	return ret;
+}
+
+/*
+ * `handle' can be NULL if create is zero
+ */
+struct buffer_head *ext3_getblk(handle_t *handle, struct inode *inode,
+				long block, int create, int *errp)
+{
+	struct buffer_head dummy;
+	int fatal = 0, err;
+
+	J_ASSERT(handle != NULL || create == 0);
+
+	dummy.b_state = 0;
+	dummy.b_blocknr = -1000;
+	buffer_trace_init(&dummy.b_history);
+	err = ext3_get_blocks_handle(handle, inode, block, 1,
+					&dummy, create, 1);
+	/*
+	 * ext3_get_blocks_handle() returns number of blocks
+	 * mapped. 0 in case of a HOLE.
+	 */
+	if (err > 0) {
+		if (err > 1)
+			WARN_ON(1);
+		err = 0;
+	}
+	*errp = err;
+	if (!err && buffer_mapped(&dummy)) {
+		struct buffer_head *bh;
+		bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
+		if (!bh) {
+			*errp = -EIO;
+			goto err;
+		}
+		if (buffer_new(&dummy)) {
+			J_ASSERT(create != 0);
+			J_ASSERT(handle != 0);
+
+			/*
+			 * Now that we do not always journal data, we should
+			 * keep in mind whether this should always journal the
+			 * new buffer as metadata.  For now, regular file
+			 * writes use ext3_get_block instead, so it's not a
+			 * problem.
+			 */
+			lock_buffer(bh);
+			BUFFER_TRACE(bh, "call get_create_access");
+			fatal = ext3_journal_get_create_access(handle, bh);
+			if (!fatal && !buffer_uptodate(bh)) {
+				memset(bh->b_data,0,inode->i_sb->s_blocksize);
+				set_buffer_uptodate(bh);
+			}
+			unlock_buffer(bh);
+			BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
+			err = ext3_journal_dirty_metadata(handle, bh);
+			if (!fatal)
+				fatal = err;
+		} else {
+			BUFFER_TRACE(bh, "not a new buffer");
+		}
+		if (fatal) {
+			*errp = fatal;
+			brelse(bh);
+			bh = NULL;
+		}
+		return bh;
+	}
+err:
+	return NULL;
+}
+
+struct buffer_head *ext3_bread(handle_t *handle, struct inode *inode,
+			       int block, int create, int *err)
+{
+	struct buffer_head * bh;
+
+	bh = ext3_getblk(handle, inode, block, create, err);
+	if (!bh)
+		return bh;
+	if (buffer_uptodate(bh))
+		return bh;
+	ll_rw_block(READ_META, 1, &bh);
+	wait_on_buffer(bh);
+	if (buffer_uptodate(bh))
+		return bh;
+	put_bh(bh);
+	*err = -EIO;
+	return NULL;
+}
+
+static int walk_page_buffers(	handle_t *handle,
+				struct buffer_head *head,
+				unsigned from,
+				unsigned to,
+				int *partial,
+				int (*fn)(	handle_t *handle,
+						struct buffer_head *bh))
+{
+	struct buffer_head *bh;
+	unsigned block_start, block_end;
+	unsigned blocksize = head->b_size;
+	int err, ret = 0;
+	struct buffer_head *next;
+
+	for (	bh = head, block_start = 0;
+		ret == 0 && (bh != head || !block_start);
+		block_start = block_end, bh = next)
+	{
+		next = bh->b_this_page;
+		block_end = block_start + blocksize;
+		if (block_end <= from || block_start >= to) {
+			if (partial && !buffer_uptodate(bh))
+				*partial = 1;
+			continue;
+		}
+		err = (*fn)(handle, bh);
+		if (!ret)
+			ret = err;
+	}
+	return ret;
+}
+
+/*
+ * To preserve ordering, it is essential that the hole instantiation and
+ * the data write be encapsulated in a single transaction.  We cannot
+ * close off a transaction and start a new one between the ext3_get_block()
+ * and the commit_write().  So doing the journal_start at the start of
+ * prepare_write() is the right place.
+ *
+ * Also, this function can nest inside ext3_writepage() ->
+ * block_write_full_page(). In that case, we *know* that ext3_writepage()
+ * has generated enough buffer credits to do the whole page.  So we won't
+ * block on the journal in that case, which is good, because the caller may
+ * be PF_MEMALLOC.
+ *
+ * By accident, ext3 can be reentered when a transaction is open via
+ * quota file writes.  If we were to commit the transaction while thus
+ * reentered, there can be a deadlock - we would be holding a quota
+ * lock, and the commit would never complete if another thread had a
+ * transaction open and was blocking on the quota lock - a ranking
+ * violation.
+ *
+ * So what we do is to rely on the fact that journal_stop/journal_start
+ * will _not_ run commit under these circumstances because handle->h_ref
+ * is elevated.  We'll still have enough credits for the tiny quotafile
+ * write.
+ */
+static int do_journal_get_write_access(handle_t *handle,
+					struct buffer_head *bh)
+{
+	if (!buffer_mapped(bh) || buffer_freed(bh))
+		return 0;
+	return ext3_journal_get_write_access(handle, bh);
+}
+
+static int ext3_prepare_write(struct file *file, struct page *page,
+			      unsigned from, unsigned to)
+{
+	struct inode *inode = page->mapping->host;
+	int ret, needed_blocks = ext3_writepage_trans_blocks(inode);
+	handle_t *handle;
+	int retries = 0;
+
+retry:
+	handle = ext3_journal_start(inode, needed_blocks);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		goto out;
+	}
+	if (test_opt(inode->i_sb, NOBH) && ext3_should_writeback_data(inode))
+		ret = nobh_prepare_write(page, from, to, ext3_get_block);
+	else
+		ret = block_prepare_write(page, from, to, ext3_get_block);
+	if (ret)
+		goto prepare_write_failed;
+
+	if (ext3_should_journal_data(inode)) {
+		ret = walk_page_buffers(handle, page_buffers(page),
+				from, to, NULL, do_journal_get_write_access);
+	}
+prepare_write_failed:
+	if (ret)
+		ext3_journal_stop(handle);
+	if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
+		goto retry;
+out:
+	return ret;
+}
+
+int ext3_journal_dirty_data(handle_t *handle, struct buffer_head *bh)
+{
+	int err = journal_dirty_data(handle, bh);
+	if (err)
+		ext3_journal_abort_handle(__FUNCTION__, __FUNCTION__,
+						bh, handle,err);
+	return err;
+}
+
+/* For commit_write() in data=journal mode */
+static int commit_write_fn(handle_t *handle, struct buffer_head *bh)
+{
+	if (!buffer_mapped(bh) || buffer_freed(bh))
+		return 0;
+	set_buffer_uptodate(bh);
+	return ext3_journal_dirty_metadata(handle, bh);
+}
+
+/*
+ * We need to pick up the new inode size which generic_commit_write gave us
+ * `file' can be NULL - eg, when called from page_symlink().
+ *
+ * ext3 never places buffers on inode->i_mapping->private_list.  metadata
+ * buffers are managed internally.
+ */
+static int ext3_ordered_commit_write(struct file *file, struct page *page,
+			     unsigned from, unsigned to)
+{
+	handle_t *handle = ext3_journal_current_handle();
+	struct inode *inode = page->mapping->host;
+	int ret = 0, ret2;
+
+	ret = walk_page_buffers(handle, page_buffers(page),
+		from, to, NULL, ext3_journal_dirty_data);
+
+	if (ret == 0) {
+		/*
+		 * generic_commit_write() will run mark_inode_dirty() if i_size
+		 * changes.  So let's piggyback the i_disksize mark_inode_dirty
+		 * into that.
+		 */
+		loff_t new_i_size;
+
+		new_i_size = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
+		if (new_i_size > EXT3_I(inode)->i_disksize)
+			EXT3_I(inode)->i_disksize = new_i_size;
+		ret = generic_commit_write(file, page, from, to);
+	}
+	ret2 = ext3_journal_stop(handle);
+	if (!ret)
+		ret = ret2;
+	return ret;
+}
+
+static int ext3_writeback_commit_write(struct file *file, struct page *page,
+			     unsigned from, unsigned to)
+{
+	handle_t *handle = ext3_journal_current_handle();
+	struct inode *inode = page->mapping->host;
+	int ret = 0, ret2;
+	loff_t new_i_size;
+
+	new_i_size = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
+	if (new_i_size > EXT3_I(inode)->i_disksize)
+		EXT3_I(inode)->i_disksize = new_i_size;
+
+	if (test_opt(inode->i_sb, NOBH) && ext3_should_writeback_data(inode))
+		ret = nobh_commit_write(file, page, from, to);
+	else
+		ret = generic_commit_write(file, page, from, to);
+
+	ret2 = ext3_journal_stop(handle);
+	if (!ret)
+		ret = ret2;
+	return ret;
+}
+
+static int ext3_journalled_commit_write(struct file *file,
+			struct page *page, unsigned from, unsigned to)
+{
+	handle_t *handle = ext3_journal_current_handle();
+	struct inode *inode = page->mapping->host;
+	int ret = 0, ret2;
+	int partial = 0;
+	loff_t pos;
+
+	/*
+	 * Here we duplicate the generic_commit_write() functionality
+	 */
+	pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
+
+	ret = walk_page_buffers(handle, page_buffers(page), from,
+				to, &partial, commit_write_fn);
+	if (!partial)
+		SetPageUptodate(page);
+	if (pos > inode->i_size)
+		i_size_write(inode, pos);
+	EXT3_I(inode)->i_state |= EXT3_STATE_JDATA;
+	if (inode->i_size > EXT3_I(inode)->i_disksize) {
+		EXT3_I(inode)->i_disksize = inode->i_size;
+		ret2 = ext3_mark_inode_dirty(handle, inode);
+		if (!ret)
+			ret = ret2;
+	}
+	ret2 = ext3_journal_stop(handle);
+	if (!ret)
+		ret = ret2;
+	return ret;
+}
+
+/*
+ * bmap() is special.  It gets used by applications such as lilo and by
+ * the swapper to find the on-disk block of a specific piece of data.
+ *
+ * Naturally, this is dangerous if the block concerned is still in the
+ * journal.  If somebody makes a swapfile on an ext3 data-journaling
+ * filesystem and enables swap, then they may get a nasty shock when the
+ * data getting swapped to that swapfile suddenly gets overwritten by
+ * the original zero's written out previously to the journal and
+ * awaiting writeback in the kernel's buffer cache.
+ *
+ * So, if we see any bmap calls here on a modified, data-journaled file,
+ * take extra steps to flush any blocks which might be in the cache.
+ */
+static sector_t ext3_bmap(struct address_space *mapping, sector_t block)
+{
+	struct inode *inode = mapping->host;
+	journal_t *journal;
+	int err;
+
+	if (EXT3_I(inode)->i_state & EXT3_STATE_JDATA) {
+		/*
+		 * This is a REALLY heavyweight approach, but the use of
+		 * bmap on dirty files is expected to be extremely rare:
+		 * only if we run lilo or swapon on a freshly made file
+		 * do we expect this to happen.
+		 *
+		 * (bmap requires CAP_SYS_RAWIO so this does not
+		 * represent an unprivileged user DOS attack --- we'd be
+		 * in trouble if mortal users could trigger this path at
+		 * will.)
+		 *
+		 * NB. EXT3_STATE_JDATA is not set on files other than
+		 * regular files.  If somebody wants to bmap a directory
+		 * or symlink and gets confused because the buffer
+		 * hasn't yet been flushed to disk, they deserve
+		 * everything they get.
+		 */
+
+		EXT3_I(inode)->i_state &= ~EXT3_STATE_JDATA;
+		journal = EXT3_JOURNAL(inode);
+		journal_lock_updates(journal);
+		err = journal_flush(journal);
+		journal_unlock_updates(journal);
+
+		if (err)
+			return 0;
+	}
+
+	return generic_block_bmap(mapping,block,ext3_get_block);
+}
+
+static int bget_one(handle_t *handle, struct buffer_head *bh)
+{
+	get_bh(bh);
+	return 0;
+}
+
+static int bput_one(handle_t *handle, struct buffer_head *bh)
+{
+	put_bh(bh);
+	return 0;
+}
+
+static int journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh)
+{
+	if (buffer_mapped(bh))
+		return ext3_journal_dirty_data(handle, bh);
+	return 0;
+}
+
+/*
+ * Note that we always start a transaction even if we're not journalling
+ * data.  This is to preserve ordering: any hole instantiation within
+ * __block_write_full_page -> ext3_get_block() should be journalled
+ * along with the data so we don't crash and then get metadata which
+ * refers to old data.
+ *
+ * In all journalling modes block_write_full_page() will start the I/O.
+ *
+ * Problem:
+ *
+ *	ext3_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
+ *		ext3_writepage()
+ *
+ * Similar for:
+ *
+ *	ext3_file_write() -> generic_file_write() -> __alloc_pages() -> ...
+ *
+ * Same applies to ext3_get_block().  We will deadlock on various things like
+ * lock_journal and i_truncate_mutex.
+ *
+ * Setting PF_MEMALLOC here doesn't work - too many internal memory
+ * allocations fail.
+ *
+ * 16May01: If we're reentered then journal_current_handle() will be
+ *	    non-zero. We simply *return*.
+ *
+ * 1 July 2001: @@@ FIXME:
+ *   In journalled data mode, a data buffer may be metadata against the
+ *   current transaction.  But the same file is part of a shared mapping
+ *   and someone does a writepage() on it.
+ *
+ *   We will move the buffer onto the async_data list, but *after* it has
+ *   been dirtied. So there's a small window where we have dirty data on
+ *   BJ_Metadata.
+ *
+ *   Note that this only applies to the last partial page in the file.  The
+ *   bit which block_write_full_page() uses prepare/commit for.  (That's
+ *   broken code anyway: it's wrong for msync()).
+ *
+ *   It's a rare case: affects the final partial page, for journalled data
+ *   where the file is subject to bith write() and writepage() in the same
+ *   transction.  To fix it we'll need a custom block_write_full_page().
+ *   We'll probably need that anyway for journalling writepage() output.
+ *
+ * We don't honour synchronous mounts for writepage().  That would be
+ * disastrous.  Any write() or metadata operation will sync the fs for
+ * us.
+ *
+ * AKPM2: if all the page's buffers are mapped to disk and !data=journal,
+ * we don't need to open a transaction here.
+ */
+static int ext3_ordered_writepage(struct page *page,
+				struct writeback_control *wbc)
+{
+	struct inode *inode = page->mapping->host;
+	struct buffer_head *page_bufs;
+	handle_t *handle = NULL;
+	int ret = 0;
+	int err;
+
+	J_ASSERT(PageLocked(page));
+
+	/*
+	 * We give up here if we're reentered, because it might be for a
+	 * different filesystem.
+	 */
+	if (ext3_journal_current_handle())
+		goto out_fail;
+
+	handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
+
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		goto out_fail;
+	}
+
+	if (!page_has_buffers(page)) {
+		create_empty_buffers(page, inode->i_sb->s_blocksize,
+				(1 << BH_Dirty)|(1 << BH_Uptodate));
+	}
+	page_bufs = page_buffers(page);
+	walk_page_buffers(handle, page_bufs, 0,
+			PAGE_CACHE_SIZE, NULL, bget_one);
+
+	ret = block_write_full_page(page, ext3_get_block, wbc);
+
+	/*
+	 * The page can become unlocked at any point now, and
+	 * truncate can then come in and change things.  So we
+	 * can't touch *page from now on.  But *page_bufs is
+	 * safe due to elevated refcount.
+	 */
+
+	/*
+	 * And attach them to the current transaction.  But only if
+	 * block_write_full_page() succeeded.  Otherwise they are unmapped,
+	 * and generally junk.
+	 */
+	if (ret == 0) {
+		err = walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE,
+					NULL, journal_dirty_data_fn);
+		if (!ret)
+			ret = err;
+	}
+	walk_page_buffers(handle, page_bufs, 0,
+			PAGE_CACHE_SIZE, NULL, bput_one);
+	err = ext3_journal_stop(handle);
+	if (!ret)
+		ret = err;
+	return ret;
+
+out_fail:
+	redirty_page_for_writepage(wbc, page);
+	unlock_page(page);
+	return ret;
+}
+
+static int ext3_writeback_writepage(struct page *page,
+				struct writeback_control *wbc)
+{
+	struct inode *inode = page->mapping->host;
+	handle_t *handle = NULL;
+	int ret = 0;
+	int err;
+
+	if (ext3_journal_current_handle())
+		goto out_fail;
+
+	handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		goto out_fail;
+	}
+
+	if (test_opt(inode->i_sb, NOBH) && ext3_should_writeback_data(inode))
+		ret = nobh_writepage(page, ext3_get_block, wbc);
+	else
+		ret = block_write_full_page(page, ext3_get_block, wbc);
+
+	err = ext3_journal_stop(handle);
+	if (!ret)
+		ret = err;
+	return ret;
+
+out_fail:
+	redirty_page_for_writepage(wbc, page);
+	unlock_page(page);
+	return ret;
+}
+
+static int ext3_journalled_writepage(struct page *page,
+				struct writeback_control *wbc)
+{
+	struct inode *inode = page->mapping->host;
+	handle_t *handle = NULL;
+	int ret = 0;
+	int err;
+
+	if (ext3_journal_current_handle())
+		goto no_write;
+
+	handle = ext3_journal_start(inode, ext3_writepage_trans_blocks(inode));
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		goto no_write;
+	}
+
+	if (!page_has_buffers(page) || PageChecked(page)) {
+		/*
+		 * It's mmapped pagecache.  Add buffers and journal it.  There
+		 * doesn't seem much point in redirtying the page here.
+		 */
+		ClearPageChecked(page);
+		ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
+					ext3_get_block);
+		if (ret != 0) {
+			ext3_journal_stop(handle);
+			goto out_unlock;
+		}
+		ret = walk_page_buffers(handle, page_buffers(page), 0,
+			PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
+
+		err = walk_page_buffers(handle, page_buffers(page), 0,
+				PAGE_CACHE_SIZE, NULL, commit_write_fn);
+		if (ret == 0)
+			ret = err;
+		EXT3_I(inode)->i_state |= EXT3_STATE_JDATA;
+		unlock_page(page);
+	} else {
+		/*
+		 * It may be a page full of checkpoint-mode buffers.  We don't
+		 * really know unless we go poke around in the buffer_heads.
+		 * But block_write_full_page will do the right thing.
+		 */
+		ret = block_write_full_page(page, ext3_get_block, wbc);
+	}
+	err = ext3_journal_stop(handle);
+	if (!ret)
+		ret = err;
+out:
+	return ret;
+
+no_write:
+	redirty_page_for_writepage(wbc, page);
+out_unlock:
+	unlock_page(page);
+	goto out;
+}
+
+static int ext3_readpage(struct file *file, struct page *page)
+{
+	return mpage_readpage(page, ext3_get_block);
+}
+
+static int
+ext3_readpages(struct file *file, struct address_space *mapping,
+		struct list_head *pages, unsigned nr_pages)
+{
+	return mpage_readpages(mapping, pages, nr_pages, ext3_get_block);
+}
+
+static void ext3_invalidatepage(struct page *page, unsigned long offset)
+{
+	journal_t *journal = EXT3_JOURNAL(page->mapping->host);
+
+	/*
+	 * If it's a full truncate we just forget about the pending dirtying
+	 */
+	if (offset == 0)
+		ClearPageChecked(page);
+
+	journal_invalidatepage(journal, page, offset);
+}
+
+static int ext3_releasepage(struct page *page, gfp_t wait)
+{
+	journal_t *journal = EXT3_JOURNAL(page->mapping->host);
+
+	WARN_ON(PageChecked(page));
+	if (!page_has_buffers(page))
+		return 0;
+	return journal_try_to_free_buffers(journal, page, wait);
+}
+
+/*
+ * If the O_DIRECT write will extend the file then add this inode to the
+ * orphan list.  So recovery will truncate it back to the original size
+ * if the machine crashes during the write.
+ *
+ * If the O_DIRECT write is intantiating holes inside i_size and the machine
+ * crashes then stale disk data _may_ be exposed inside the file.
+ */
+static ssize_t ext3_direct_IO(int rw, struct kiocb *iocb,
+			const struct iovec *iov, loff_t offset,
+			unsigned long nr_segs)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file->f_mapping->host;
+	struct ext3_inode_info *ei = EXT3_I(inode);
+	handle_t *handle = NULL;
+	ssize_t ret;
+	int orphan = 0;
+	size_t count = iov_length(iov, nr_segs);
+
+	if (rw == WRITE) {
+		loff_t final_size = offset + count;
+
+		handle = ext3_journal_start(inode, DIO_CREDITS);
+		if (IS_ERR(handle)) {
+			ret = PTR_ERR(handle);
+			goto out;
+		}
+		if (final_size > inode->i_size) {
+			ret = ext3_orphan_add(handle, inode);
+			if (ret)
+				goto out_stop;
+			orphan = 1;
+			ei->i_disksize = inode->i_size;
+		}
+	}
+
+	ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
+				 offset, nr_segs,
+				 ext3_get_block, NULL);
+
+	/*
+	 * Reacquire the handle: ext3_get_block() can restart the transaction
+	 */
+	handle = journal_current_handle();
+
+out_stop:
+	if (handle) {
+		int err;
+
+		if (orphan && inode->i_nlink)
+			ext3_orphan_del(handle, inode);
+		if (orphan && ret > 0) {
+			loff_t end = offset + ret;
+			if (end > inode->i_size) {
+				ei->i_disksize = end;
+				i_size_write(inode, end);
+				/*
+				 * We're going to return a positive `ret'
+				 * here due to non-zero-length I/O, so there's
+				 * no way of reporting error returns from
+				 * ext3_mark_inode_dirty() to userspace.  So
+				 * ignore it.
+				 */
+				ext3_mark_inode_dirty(handle, inode);
+			}
+		}
+		err = ext3_journal_stop(handle);
+		if (ret == 0)
+			ret = err;
+	}
+out:
+	return ret;
+}
+
+/*
+ * Pages can be marked dirty completely asynchronously from ext3's journalling
+ * activity.  By filemap_sync_pte(), try_to_unmap_one(), etc.  We cannot do
+ * much here because ->set_page_dirty is called under VFS locks.  The page is
+ * not necessarily locked.
+ *
+ * We cannot just dirty the page and leave attached buffers clean, because the
+ * buffers' dirty state is "definitive".  We cannot just set the buffers dirty
+ * or jbddirty because all the journalling code will explode.
+ *
+ * So what we do is to mark the page "pending dirty" and next time writepage
+ * is called, propagate that into the buffers appropriately.
+ */
+static int ext3_journalled_set_page_dirty(struct page *page)
+{
+	SetPageChecked(page);
+	return __set_page_dirty_nobuffers(page);
+}
+
+static const struct address_space_operations ext3_ordered_aops = {
+	.readpage	= ext3_readpage,
+	.readpages	= ext3_readpages,
+	.writepage	= ext3_ordered_writepage,
+	.sync_page	= block_sync_page,
+	.prepare_write	= ext3_prepare_write,
+	.commit_write	= ext3_ordered_commit_write,
+	.bmap		= ext3_bmap,
+	.invalidatepage	= ext3_invalidatepage,
+	.releasepage	= ext3_releasepage,
+	.direct_IO	= ext3_direct_IO,
+	.migratepage	= buffer_migrate_page,
+};
+
+static const struct address_space_operations ext3_writeback_aops = {
+	.readpage	= ext3_readpage,
+	.readpages	= ext3_readpages,
+	.writepage	= ext3_writeback_writepage,
+	.sync_page	= block_sync_page,
+	.prepare_write	= ext3_prepare_write,
+	.commit_write	= ext3_writeback_commit_write,
+	.bmap		= ext3_bmap,
+	.invalidatepage	= ext3_invalidatepage,
+	.releasepage	= ext3_releasepage,
+	.direct_IO	= ext3_direct_IO,
+	.migratepage	= buffer_migrate_page,
+};
+
+static const struct address_space_operations ext3_journalled_aops = {
+	.readpage	= ext3_readpage,
+	.readpages	= ext3_readpages,
+	.writepage	= ext3_journalled_writepage,
+	.sync_page	= block_sync_page,
+	.prepare_write	= ext3_prepare_write,
+	.commit_write	= ext3_journalled_commit_write,
+	.set_page_dirty	= ext3_journalled_set_page_dirty,
+	.bmap		= ext3_bmap,
+	.invalidatepage	= ext3_invalidatepage,
+	.releasepage	= ext3_releasepage,
+};
+
+void ext3_set_aops(struct inode *inode)
+{
+	if (ext3_should_order_data(inode))
+		inode->i_mapping->a_ops = &ext3_ordered_aops;
+	else if (ext3_should_writeback_data(inode))
+		inode->i_mapping->a_ops = &ext3_writeback_aops;
+	else
+		inode->i_mapping->a_ops = &ext3_journalled_aops;
+}
+
+/*
+ * ext3_block_truncate_page() zeroes out a mapping from file offset `from'
+ * up to the end of the block which corresponds to `from'.
+ * This required during truncate. We need to physically zero the tail end
+ * of that block so it doesn't yield old data if the file is later grown.
+ */
+static int ext3_block_truncate_page(handle_t *handle, struct page *page,
+		struct address_space *mapping, loff_t from)
+{
+	ext3_fsblk_t index = from >> PAGE_CACHE_SHIFT;
+	unsigned offset = from & (PAGE_CACHE_SIZE-1);
+	unsigned blocksize, iblock, length, pos;
+	struct inode *inode = mapping->host;
+	struct buffer_head *bh;
+	int err = 0;
+	void *kaddr;
+
+	blocksize = inode->i_sb->s_blocksize;
+	length = blocksize - (offset & (blocksize - 1));
+	iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
+
+	/*
+	 * For "nobh" option,  we can only work if we don't need to
+	 * read-in the page - otherwise we create buffers to do the IO.
+	 */
+	if (!page_has_buffers(page) && test_opt(inode->i_sb, NOBH) &&
+	     ext3_should_writeback_data(inode) && PageUptodate(page)) {
+		kaddr = kmap_atomic(page, KM_USER0);
+		memset(kaddr + offset, 0, length);
+		flush_dcache_page(page);
+		kunmap_atomic(kaddr, KM_USER0);
+		set_page_dirty(page);
+		goto unlock;
+	}
+
+	if (!page_has_buffers(page))
+		create_empty_buffers(page, blocksize, 0);
+
+	/* Find the buffer that contains "offset" */
+	bh = page_buffers(page);
+	pos = blocksize;
+	while (offset >= pos) {
+		bh = bh->b_this_page;
+		iblock++;
+		pos += blocksize;
+	}
+
+	err = 0;
+	if (buffer_freed(bh)) {
+		BUFFER_TRACE(bh, "freed: skip");
+		goto unlock;
+	}
+
+	if (!buffer_mapped(bh)) {
+		BUFFER_TRACE(bh, "unmapped");
+		ext3_get_block(inode, iblock, bh, 0);
+		/* unmapped? It's a hole - nothing to do */
+		if (!buffer_mapped(bh)) {
+			BUFFER_TRACE(bh, "still unmapped");
+			goto unlock;
+		}
+	}
+
+	/* Ok, it's mapped. Make sure it's up-to-date */
+	if (PageUptodate(page))
+		set_buffer_uptodate(bh);
+
+	if (!buffer_uptodate(bh)) {
+		err = -EIO;
+		ll_rw_block(READ, 1, &bh);
+		wait_on_buffer(bh);
+		/* Uhhuh. Read error. Complain and punt. */
+		if (!buffer_uptodate(bh))
+			goto unlock;
+	}
+
+	if (ext3_should_journal_data(inode)) {
+		BUFFER_TRACE(bh, "get write access");
+		err = ext3_journal_get_write_access(handle, bh);
+		if (err)
+			goto unlock;
+	}
+
+	kaddr = kmap_atomic(page, KM_USER0);
+	memset(kaddr + offset, 0, length);
+	flush_dcache_page(page);
+	kunmap_atomic(kaddr, KM_USER0);
+
+	BUFFER_TRACE(bh, "zeroed end of block");
+
+	err = 0;
+	if (ext3_should_journal_data(inode)) {
+		err = ext3_journal_dirty_metadata(handle, bh);
+	} else {
+		if (ext3_should_order_data(inode))
+			err = ext3_journal_dirty_data(handle, bh);
+		mark_buffer_dirty(bh);
+	}
+
+unlock:
+	unlock_page(page);
+	page_cache_release(page);
+	return err;
+}
+
+/*
+ * Probably it should be a library function... search for first non-zero word
+ * or memcmp with zero_page, whatever is better for particular architecture.
+ * Linus?
+ */
+static inline int all_zeroes(__le32 *p, __le32 *q)
+{
+	while (p < q)
+		if (*p++)
+			return 0;
+	return 1;
+}
+
+/**
+ *	ext3_find_shared - find the indirect blocks for partial truncation.
+ *	@inode:	  inode in question
+ *	@depth:	  depth of the affected branch
+ *	@offsets: offsets of pointers in that branch (see ext3_block_to_path)
+ *	@chain:	  place to store the pointers to partial indirect blocks
+ *	@top:	  place to the (detached) top of branch
+ *
+ *	This is a helper function used by ext3_truncate().
+ *
+ *	When we do truncate() we may have to clean the ends of several
+ *	indirect blocks but leave the blocks themselves alive. Block is
+ *	partially truncated if some data below the new i_size is refered
+ *	from it (and it is on the path to the first completely truncated
+ *	data block, indeed).  We have to free the top of that path along
+ *	with everything to the right of the path. Since no allocation
+ *	past the truncation point is possible until ext3_truncate()
+ *	finishes, we may safely do the latter, but top of branch may
+ *	require special attention - pageout below the truncation point
+ *	might try to populate it.
+ *
+ *	We atomically detach the top of branch from the tree, store the
+ *	block number of its root in *@top, pointers to buffer_heads of
+ *	partially truncated blocks - in @chain[].bh and pointers to
+ *	their last elements that should not be removed - in
+ *	@chain[].p. Return value is the pointer to last filled element
+ *	of @chain.
+ *
+ *	The work left to caller to do the actual freeing of subtrees:
+ *		a) free the subtree starting from *@top
+ *		b) free the subtrees whose roots are stored in
+ *			(@chain[i].p+1 .. end of @chain[i].bh->b_data)
+ *		c) free the subtrees growing from the inode past the @chain[0].
+ *			(no partially truncated stuff there).  */
+
+static Indirect *ext3_find_shared(struct inode *inode, int depth,
+			int offsets[4], Indirect chain[4], __le32 *top)
+{
+	Indirect *partial, *p;
+	int k, err;
+
+	*top = 0;
+	/* Make k index the deepest non-null offest + 1 */
+	for (k = depth; k > 1 && !offsets[k-1]; k--)
+		;
+	partial = ext3_get_branch(inode, k, offsets, chain, &err);
+	/* Writer: pointers */
+	if (!partial)
+		partial = chain + k-1;
+	/*
+	 * If the branch acquired continuation since we've looked at it -
+	 * fine, it should all survive and (new) top doesn't belong to us.
+	 */
+	if (!partial->key && *partial->p)
+		/* Writer: end */
+		goto no_top;
+	for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
+		;
+	/*
+	 * OK, we've found the last block that must survive. The rest of our
+	 * branch should be detached before unlocking. However, if that rest
+	 * of branch is all ours and does not grow immediately from the inode
+	 * it's easier to cheat and just decrement partial->p.
+	 */
+	if (p == chain + k - 1 && p > chain) {
+		p->p--;
+	} else {
+		*top = *p->p;
+		/* Nope, don't do this in ext3.  Must leave the tree intact */
+#if 0
+		*p->p = 0;
+#endif
+	}
+	/* Writer: end */
+
+	while(partial > p) {
+		brelse(partial->bh);
+		partial--;
+	}
+no_top:
+	return partial;
+}
+
+/*
+ * Zero a number of block pointers in either an inode or an indirect block.
+ * If we restart the transaction we must again get write access to the
+ * indirect block for further modification.
+ *
+ * We release `count' blocks on disk, but (last - first) may be greater
+ * than `count' because there can be holes in there.
+ */
+static void ext3_clear_blocks(handle_t *handle, struct inode *inode,
+		struct buffer_head *bh, ext3_fsblk_t block_to_free,
+		unsigned long count, __le32 *first, __le32 *last)
+{
+	__le32 *p;
+	if (try_to_extend_transaction(handle, inode)) {
+		if (bh) {
+			BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
+			ext3_journal_dirty_metadata(handle, bh);
+		}
+		ext3_mark_inode_dirty(handle, inode);
+		ext3_journal_test_restart(handle, inode);
+		if (bh) {
+			BUFFER_TRACE(bh, "retaking write access");
+			ext3_journal_get_write_access(handle, bh);
+		}
+	}
+
+	/*
+	 * Any buffers which are on the journal will be in memory. We find
+	 * them on the hash table so journal_revoke() will run journal_forget()
+	 * on them.  We've already detached each block from the file, so
+	 * bforget() in journal_forget() should be safe.
+	 *
+	 * AKPM: turn on bforget in journal_forget()!!!
+	 */
+	for (p = first; p < last; p++) {
+		u32 nr = le32_to_cpu(*p);
+		if (nr) {
+			struct buffer_head *bh;
+
+			*p = 0;
+			bh = sb_find_get_block(inode->i_sb, nr);
+			ext3_forget(handle, 0, inode, bh, nr);
+		}
+	}
+
+	ext3_free_blocks(handle, inode, block_to_free, count);
+}
+
+/**
+ * ext3_free_data - free a list of data blocks
+ * @handle:	handle for this transaction
+ * @inode:	inode we are dealing with
+ * @this_bh:	indirect buffer_head which contains *@first and *@last
+ * @first:	array of block numbers
+ * @last:	points immediately past the end of array
+ *
+ * We are freeing all blocks refered from that array (numbers are stored as
+ * little-endian 32-bit) and updating @inode->i_blocks appropriately.
+ *
+ * We accumulate contiguous runs of blocks to free.  Conveniently, if these
+ * blocks are contiguous then releasing them at one time will only affect one
+ * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
+ * actually use a lot of journal space.
+ *
+ * @this_bh will be %NULL if @first and @last point into the inode's direct
+ * block pointers.
+ */
+static void ext3_free_data(handle_t *handle, struct inode *inode,
+			   struct buffer_head *this_bh,
+			   __le32 *first, __le32 *last)
+{
+	ext3_fsblk_t block_to_free = 0;    /* Starting block # of a run */
+	unsigned long count = 0;	    /* Number of blocks in the run */
+	__le32 *block_to_free_p = NULL;	    /* Pointer into inode/ind
+					       corresponding to
+					       block_to_free */
+	ext3_fsblk_t nr;		    /* Current block # */
+	__le32 *p;			    /* Pointer into inode/ind
+					       for current block */
+	int err;
+
+	if (this_bh) {				/* For indirect block */
+		BUFFER_TRACE(this_bh, "get_write_access");
+		err = ext3_journal_get_write_access(handle, this_bh);
+		/* Important: if we can't update the indirect pointers
+		 * to the blocks, we can't free them. */
+		if (err)
+			return;
+	}
+
+	for (p = first; p < last; p++) {
+		nr = le32_to_cpu(*p);
+		if (nr) {
+			/* accumulate blocks to free if they're contiguous */
+			if (count == 0) {
+				block_to_free = nr;
+				block_to_free_p = p;
+				count = 1;
+			} else if (nr == block_to_free + count) {
+				count++;
+			} else {
+				ext3_clear_blocks(handle, inode, this_bh,
+						  block_to_free,
+						  count, block_to_free_p, p);
+				block_to_free = nr;
+				block_to_free_p = p;
+				count = 1;
+			}
+		}
+	}
+
+	if (count > 0)
+		ext3_clear_blocks(handle, inode, this_bh, block_to_free,
+				  count, block_to_free_p, p);
+
+	if (this_bh) {
+		BUFFER_TRACE(this_bh, "call ext3_journal_dirty_metadata");
+		ext3_journal_dirty_metadata(handle, this_bh);
+	}
+}
+
+/**
+ *	ext3_free_branches - free an array of branches
+ *	@handle: JBD handle for this transaction
+ *	@inode:	inode we are dealing with
+ *	@parent_bh: the buffer_head which contains *@first and *@last
+ *	@first:	array of block numbers
+ *	@last:	pointer immediately past the end of array
+ *	@depth:	depth of the branches to free
+ *
+ *	We are freeing all blocks refered from these branches (numbers are
+ *	stored as little-endian 32-bit) and updating @inode->i_blocks
+ *	appropriately.
+ */
+static void ext3_free_branches(handle_t *handle, struct inode *inode,
+			       struct buffer_head *parent_bh,
+			       __le32 *first, __le32 *last, int depth)
+{
+	ext3_fsblk_t nr;
+	__le32 *p;
+
+	if (is_handle_aborted(handle))
+		return;
+
+	if (depth--) {
+		struct buffer_head *bh;
+		int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
+		p = last;
+		while (--p >= first) {
+			nr = le32_to_cpu(*p);
+			if (!nr)
+				continue;		/* A hole */
+
+			/* Go read the buffer for the next level down */
+			bh = sb_bread(inode->i_sb, nr);
+
+			/*
+			 * A read failure? Report error and clear slot
+			 * (should be rare).
+			 */
+			if (!bh) {
+				ext3_error(inode->i_sb, "ext3_free_branches",
+					   "Read failure, inode=%lu, block="E3FSBLK,
+					   inode->i_ino, nr);
+				continue;
+			}
+
+			/* This zaps the entire block.  Bottom up. */
+			BUFFER_TRACE(bh, "free child branches");
+			ext3_free_branches(handle, inode, bh,
+					   (__le32*)bh->b_data,
+					   (__le32*)bh->b_data + addr_per_block,
+					   depth);
+
+			/*
+			 * We've probably journalled the indirect block several
+			 * times during the truncate.  But it's no longer
+			 * needed and we now drop it from the transaction via
+			 * journal_revoke().
+			 *
+			 * That's easy if it's exclusively part of this
+			 * transaction.  But if it's part of the committing
+			 * transaction then journal_forget() will simply
+			 * brelse() it.  That means that if the underlying
+			 * block is reallocated in ext3_get_block(),
+			 * unmap_underlying_metadata() will find this block
+			 * and will try to get rid of it.  damn, damn.
+			 *
+			 * If this block has already been committed to the
+			 * journal, a revoke record will be written.  And
+			 * revoke records must be emitted *before* clearing
+			 * this block's bit in the bitmaps.
+			 */
+			ext3_forget(handle, 1, inode, bh, bh->b_blocknr);
+
+			/*
+			 * Everything below this this pointer has been
+			 * released.  Now let this top-of-subtree go.
+			 *
+			 * We want the freeing of this indirect block to be
+			 * atomic in the journal with the updating of the
+			 * bitmap block which owns it.  So make some room in
+			 * the journal.
+			 *
+			 * We zero the parent pointer *after* freeing its
+			 * pointee in the bitmaps, so if extend_transaction()
+			 * for some reason fails to put the bitmap changes and
+			 * the release into the same transaction, recovery
+			 * will merely complain about releasing a free block,
+			 * rather than leaking blocks.
+			 */
+			if (is_handle_aborted(handle))
+				return;
+			if (try_to_extend_transaction(handle, inode)) {
+				ext3_mark_inode_dirty(handle, inode);
+				ext3_journal_test_restart(handle, inode);
+			}
+
+			ext3_free_blocks(handle, inode, nr, 1);
+
+			if (parent_bh) {
+				/*
+				 * The block which we have just freed is
+				 * pointed to by an indirect block: journal it
+				 */
+				BUFFER_TRACE(parent_bh, "get_write_access");
+				if (!ext3_journal_get_write_access(handle,
+								   parent_bh)){
+					*p = 0;
+					BUFFER_TRACE(parent_bh,
+					"call ext3_journal_dirty_metadata");
+					ext3_journal_dirty_metadata(handle,
+								    parent_bh);
+				}
+			}
+		}
+	} else {
+		/* We have reached the bottom of the tree. */
+		BUFFER_TRACE(parent_bh, "free data blocks");
+		ext3_free_data(handle, inode, parent_bh, first, last);
+	}
+}
+
+/*
+ * ext3_truncate()
+ *
+ * We block out ext3_get_block() block instantiations across the entire
+ * transaction, and VFS/VM ensures that ext3_truncate() cannot run
+ * simultaneously on behalf of the same inode.
+ *
+ * As we work through the truncate and commmit bits of it to the journal there
+ * is one core, guiding principle: the file's tree must always be consistent on
+ * disk.  We must be able to restart the truncate after a crash.
+ *
+ * The file's tree may be transiently inconsistent in memory (although it
+ * probably isn't), but whenever we close off and commit a journal transaction,
+ * the contents of (the filesystem + the journal) must be consistent and
+ * restartable.  It's pretty simple, really: bottom up, right to left (although
+ * left-to-right works OK too).
+ *
+ * Note that at recovery time, journal replay occurs *before* the restart of
+ * truncate against the orphan inode list.
+ *
+ * The committed inode has the new, desired i_size (which is the same as
+ * i_disksize in this case).  After a crash, ext3_orphan_cleanup() will see
+ * that this inode's truncate did not complete and it will again call
+ * ext3_truncate() to have another go.  So there will be instantiated blocks
+ * to the right of the truncation point in a crashed ext3 filesystem.  But
+ * that's fine - as long as they are linked from the inode, the post-crash
+ * ext3_truncate() run will find them and release them.
+ */
+void ext3_truncate(struct inode *inode)
+{
+	handle_t *handle;
+	struct ext3_inode_info *ei = EXT3_I(inode);
+	__le32 *i_data = ei->i_data;
+	int addr_per_block = EXT3_ADDR_PER_BLOCK(inode->i_sb);
+	struct address_space *mapping = inode->i_mapping;
+	int offsets[4];
+	Indirect chain[4];
+	Indirect *partial;
+	__le32 nr = 0;
+	int n;
+	long last_block;
+	unsigned blocksize = inode->i_sb->s_blocksize;
+	struct page *page;
+
+	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
+	    S_ISLNK(inode->i_mode)))
+		return;
+	if (ext3_inode_is_fast_symlink(inode))
+		return;
+	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
+		return;
+
+	/*
+	 * We have to lock the EOF page here, because lock_page() nests
+	 * outside journal_start().
+	 */
+	if ((inode->i_size & (blocksize - 1)) == 0) {
+		/* Block boundary? Nothing to do */
+		page = NULL;
+	} else {
+		page = grab_cache_page(mapping,
+				inode->i_size >> PAGE_CACHE_SHIFT);
+		if (!page)
+			return;
+	}
+
+	handle = start_transaction(inode);
+	if (IS_ERR(handle)) {
+		if (page) {
+			clear_highpage(page);
+			flush_dcache_page(page);
+			unlock_page(page);
+			page_cache_release(page);
+		}
+		return;		/* AKPM: return what? */
+	}
+
+	last_block = (inode->i_size + blocksize-1)
+					>> EXT3_BLOCK_SIZE_BITS(inode->i_sb);
+
+	if (page)
+		ext3_block_truncate_page(handle, page, mapping, inode->i_size);
+
+	n = ext3_block_to_path(inode, last_block, offsets, NULL);
+	if (n == 0)
+		goto out_stop;	/* error */
+
+	/*
+	 * OK.  This truncate is going to happen.  We add the inode to the
+	 * orphan list, so that if this truncate spans multiple transactions,
+	 * and we crash, we will resume the truncate when the filesystem
+	 * recovers.  It also marks the inode dirty, to catch the new size.
+	 *
+	 * Implication: the file must always be in a sane, consistent
+	 * truncatable state while each transaction commits.
+	 */
+	if (ext3_orphan_add(handle, inode))
+		goto out_stop;
+
+	/*
+	 * The orphan list entry will now protect us from any crash which
+	 * occurs before the truncate completes, so it is now safe to propagate
+	 * the new, shorter inode size (held for now in i_size) into the
+	 * on-disk inode. We do this via i_disksize, which is the value which
+	 * ext3 *really* writes onto the disk inode.
+	 */
+	ei->i_disksize = inode->i_size;
+
+	/*
+	 * From here we block out all ext3_get_block() callers who want to
+	 * modify the block allocation tree.
+	 */
+	mutex_lock(&ei->truncate_mutex);
+
+	if (n == 1) {		/* direct blocks */
+		ext3_free_data(handle, inode, NULL, i_data+offsets[0],
+			       i_data + EXT3_NDIR_BLOCKS);
+		goto do_indirects;
+	}
+
+	partial = ext3_find_shared(inode, n, offsets, chain, &nr);
+	/* Kill the top of shared branch (not detached) */
+	if (nr) {
+		if (partial == chain) {
+			/* Shared branch grows from the inode */
+			ext3_free_branches(handle, inode, NULL,
+					   &nr, &nr+1, (chain+n-1) - partial);
+			*partial->p = 0;
+			/*
+			 * We mark the inode dirty prior to restart,
+			 * and prior to stop.  No need for it here.
+			 */
+		} else {
+			/* Shared branch grows from an indirect block */
+			BUFFER_TRACE(partial->bh, "get_write_access");
+			ext3_free_branches(handle, inode, partial->bh,
+					partial->p,
+					partial->p+1, (chain+n-1) - partial);
+		}
+	}
+	/* Clear the ends of indirect blocks on the shared branch */
+	while (partial > chain) {
+		ext3_free_branches(handle, inode, partial->bh, partial->p + 1,
+				   (__le32*)partial->bh->b_data+addr_per_block,
+				   (chain+n-1) - partial);
+		BUFFER_TRACE(partial->bh, "call brelse");
+		brelse (partial->bh);
+		partial--;
+	}
+do_indirects:
+	/* Kill the remaining (whole) subtrees */
+	switch (offsets[0]) {
+	default:
+		nr = i_data[EXT3_IND_BLOCK];
+		if (nr) {
+			ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
+			i_data[EXT3_IND_BLOCK] = 0;
+		}
+	case EXT3_IND_BLOCK:
+		nr = i_data[EXT3_DIND_BLOCK];
+		if (nr) {
+			ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
+			i_data[EXT3_DIND_BLOCK] = 0;
+		}
+	case EXT3_DIND_BLOCK:
+		nr = i_data[EXT3_TIND_BLOCK];
+		if (nr) {
+			ext3_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
+			i_data[EXT3_TIND_BLOCK] = 0;
+		}
+	case EXT3_TIND_BLOCK:
+		;
+	}
+
+	ext3_discard_reservation(inode);
+
+	mutex_unlock(&ei->truncate_mutex);
+	inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
+	ext3_mark_inode_dirty(handle, inode);
+
+	/*
+	 * In a multi-transaction truncate, we only make the final transaction
+	 * synchronous
+	 */
+	if (IS_SYNC(inode))
+		handle->h_sync = 1;
+out_stop:
+	/*
+	 * If this was a simple ftruncate(), and the file will remain alive
+	 * then we need to clear up the orphan record which we created above.
+	 * However, if this was a real unlink then we were called by
+	 * ext3_delete_inode(), and we allow that function to clean up the
+	 * orphan info for us.
+	 */
+	if (inode->i_nlink)
+		ext3_orphan_del(handle, inode);
+
+	ext3_journal_stop(handle);
+}
+
+static ext3_fsblk_t ext3_get_inode_block(struct super_block *sb,
+		unsigned long ino, struct ext3_iloc *iloc)
+{
+	unsigned long desc, group_desc, block_group;
+	unsigned long offset;
+	ext3_fsblk_t block;
+	struct buffer_head *bh;
+	struct ext3_group_desc * gdp;
+
+	if (!ext3_valid_inum(sb, ino)) {
+		/*
+		 * This error is already checked for in namei.c unless we are
+		 * looking at an NFS filehandle, in which case no error
+		 * report is needed
+		 */
+		return 0;
+	}
+
+	block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb);
+	if (block_group >= EXT3_SB(sb)->s_groups_count) {
+		ext3_error(sb,"ext3_get_inode_block","group >= groups count");
+		return 0;
+	}
+	smp_rmb();
+	group_desc = block_group >> EXT3_DESC_PER_BLOCK_BITS(sb);
+	desc = block_group & (EXT3_DESC_PER_BLOCK(sb) - 1);
+	bh = EXT3_SB(sb)->s_group_desc[group_desc];
+	if (!bh) {
+		ext3_error (sb, "ext3_get_inode_block",
+			    "Descriptor not loaded");
+		return 0;
+	}
+
+	gdp = (struct ext3_group_desc *)bh->b_data;
+	/*
+	 * Figure out the offset within the block group inode table
+	 */
+	offset = ((ino - 1) % EXT3_INODES_PER_GROUP(sb)) *
+		EXT3_INODE_SIZE(sb);
+	block = le32_to_cpu(gdp[desc].bg_inode_table) +
+		(offset >> EXT3_BLOCK_SIZE_BITS(sb));
+
+	iloc->block_group = block_group;
+	iloc->offset = offset & (EXT3_BLOCK_SIZE(sb) - 1);
+	return block;
+}
+
+/*
+ * ext3_get_inode_loc returns with an extra refcount against the inode's
+ * underlying buffer_head on success. If 'in_mem' is true, we have all
+ * data in memory that is needed to recreate the on-disk version of this
+ * inode.
+ */
+static int __ext3_get_inode_loc(struct inode *inode,
+				struct ext3_iloc *iloc, int in_mem)
+{
+	ext3_fsblk_t block;
+	struct buffer_head *bh;
+
+	block = ext3_get_inode_block(inode->i_sb, inode->i_ino, iloc);
+	if (!block)
+		return -EIO;
+
+	bh = sb_getblk(inode->i_sb, block);
+	if (!bh) {
+		ext3_error (inode->i_sb, "ext3_get_inode_loc",
+				"unable to read inode block - "
+				"inode=%lu, block="E3FSBLK,
+				 inode->i_ino, block);
+		return -EIO;
+	}
+	if (!buffer_uptodate(bh)) {
+		lock_buffer(bh);
+		if (buffer_uptodate(bh)) {
+			/* someone brought it uptodate while we waited */
+			unlock_buffer(bh);
+			goto has_buffer;
+		}
+
+		/*
+		 * If we have all information of the inode in memory and this
+		 * is the only valid inode in the block, we need not read the
+		 * block.
+		 */
+		if (in_mem) {
+			struct buffer_head *bitmap_bh;
+			struct ext3_group_desc *desc;
+			int inodes_per_buffer;
+			int inode_offset, i;
+			int block_group;
+			int start;
+
+			block_group = (inode->i_ino - 1) /
+					EXT3_INODES_PER_GROUP(inode->i_sb);
+			inodes_per_buffer = bh->b_size /
+				EXT3_INODE_SIZE(inode->i_sb);
+			inode_offset = ((inode->i_ino - 1) %
+					EXT3_INODES_PER_GROUP(inode->i_sb));
+			start = inode_offset & ~(inodes_per_buffer - 1);
+
+			/* Is the inode bitmap in cache? */
+			desc = ext3_get_group_desc(inode->i_sb,
+						block_group, NULL);
+			if (!desc)
+				goto make_io;
+
+			bitmap_bh = sb_getblk(inode->i_sb,
+					le32_to_cpu(desc->bg_inode_bitmap));
+			if (!bitmap_bh)
+				goto make_io;
+
+			/*
+			 * If the inode bitmap isn't in cache then the
+			 * optimisation may end up performing two reads instead
+			 * of one, so skip it.
+			 */
+			if (!buffer_uptodate(bitmap_bh)) {
+				brelse(bitmap_bh);
+				goto make_io;
+			}
+			for (i = start; i < start + inodes_per_buffer; i++) {
+				if (i == inode_offset)
+					continue;
+				if (ext3_test_bit(i, bitmap_bh->b_data))
+					break;
+			}
+			brelse(bitmap_bh);
+			if (i == start + inodes_per_buffer) {
+				/* all other inodes are free, so skip I/O */
+				memset(bh->b_data, 0, bh->b_size);
+				set_buffer_uptodate(bh);
+				unlock_buffer(bh);
+				goto has_buffer;
+			}
+		}
+
+make_io:
+		/*
+		 * There are other valid inodes in the buffer, this inode
+		 * has in-inode xattrs, or we don't have this inode in memory.
+		 * Read the block from disk.
+		 */
+		get_bh(bh);
+		bh->b_end_io = end_buffer_read_sync;
+		submit_bh(READ_META, bh);
+		wait_on_buffer(bh);
+		if (!buffer_uptodate(bh)) {
+			ext3_error(inode->i_sb, "ext3_get_inode_loc",
+					"unable to read inode block - "
+					"inode=%lu, block="E3FSBLK,
+					inode->i_ino, block);
+			brelse(bh);
+			return -EIO;
+		}
+	}
+has_buffer:
+	iloc->bh = bh;
+	return 0;
+}
+
+int ext3_get_inode_loc(struct inode *inode, struct ext3_iloc *iloc)
+{
+	/* We have all inode data except xattrs in memory here. */
+	return __ext3_get_inode_loc(inode, iloc,
+		!(EXT3_I(inode)->i_state & EXT3_STATE_XATTR));
+}
+
+void ext3_set_inode_flags(struct inode *inode)
+{
+	unsigned int flags = EXT3_I(inode)->i_flags;
+
+	inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
+	if (flags & EXT3_SYNC_FL)
+		inode->i_flags |= S_SYNC;
+	if (flags & EXT3_APPEND_FL)
+		inode->i_flags |= S_APPEND;
+	if (flags & EXT3_IMMUTABLE_FL)
+		inode->i_flags |= S_IMMUTABLE;
+	if (flags & EXT3_NOATIME_FL)
+		inode->i_flags |= S_NOATIME;
+	if (flags & EXT3_DIRSYNC_FL)
+		inode->i_flags |= S_DIRSYNC;
+}
+
+void ext3_read_inode(struct inode * inode)
+{
+	struct ext3_iloc iloc;
+	struct ext3_inode *raw_inode;
+	struct ext3_inode_info *ei = EXT3_I(inode);
+	struct buffer_head *bh;
+	int block;
+
+#ifdef CONFIG_EXT3_FS_POSIX_ACL
+	ei->i_acl = EXT3_ACL_NOT_CACHED;
+	ei->i_default_acl = EXT3_ACL_NOT_CACHED;
+#endif
+	ei->i_block_alloc_info = NULL;
+
+	if (__ext3_get_inode_loc(inode, &iloc, 0))
+		goto bad_inode;
+	bh = iloc.bh;
+	raw_inode = ext3_raw_inode(&iloc);
+	inode->i_mode = le16_to_cpu(raw_inode->i_mode);
+	inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
+	inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
+	if(!(test_opt (inode->i_sb, NO_UID32))) {
+		inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
+		inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
+	}
+	inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
+	inode->i_size = le32_to_cpu(raw_inode->i_size);
+	inode->i_atime.tv_sec = le32_to_cpu(raw_inode->i_atime);
+	inode->i_ctime.tv_sec = le32_to_cpu(raw_inode->i_ctime);
+	inode->i_mtime.tv_sec = le32_to_cpu(raw_inode->i_mtime);
+	inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = inode->i_mtime.tv_nsec = 0;
+
+	ei->i_state = 0;
+	ei->i_dir_start_lookup = 0;
+	ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
+	/* We now have enough fields to check if the inode was active or not.
+	 * This is needed because nfsd might try to access dead inodes
+	 * the test is that same one that e2fsck uses
+	 * NeilBrown 1999oct15
+	 */
+	if (inode->i_nlink == 0) {
+		if (inode->i_mode == 0 ||
+		    !(EXT3_SB(inode->i_sb)->s_mount_state & EXT3_ORPHAN_FS)) {
+			/* this inode is deleted */
+			brelse (bh);
+			goto bad_inode;
+		}
+		/* The only unlinked inodes we let through here have
+		 * valid i_mode and are being read by the orphan
+		 * recovery code: that's fine, we're about to complete
+		 * the process of deleting those. */
+	}
+	inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
+	ei->i_flags = le32_to_cpu(raw_inode->i_flags);
+#ifdef EXT3_FRAGMENTS
+	ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
+	ei->i_frag_no = raw_inode->i_frag;
+	ei->i_frag_size = raw_inode->i_fsize;
+#endif
+	ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
+	if (!S_ISREG(inode->i_mode)) {
+		ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
+	} else {
+		inode->i_size |=
+			((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
+	}
+	ei->i_disksize = inode->i_size;
+	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
+	ei->i_block_group = iloc.block_group;
+	/*
+	 * NOTE! The in-memory inode i_data array is in little-endian order
+	 * even on big-endian machines: we do NOT byteswap the block numbers!
+	 */
+	for (block = 0; block < EXT3_N_BLOCKS; block++)
+		ei->i_data[block] = raw_inode->i_block[block];
+	INIT_LIST_HEAD(&ei->i_orphan);
+
+	if (inode->i_ino >= EXT3_FIRST_INO(inode->i_sb) + 1 &&
+	    EXT3_INODE_SIZE(inode->i_sb) > EXT3_GOOD_OLD_INODE_SIZE) {
+		/*
+		 * When mke2fs creates big inodes it does not zero out
+		 * the unused bytes above EXT3_GOOD_OLD_INODE_SIZE,
+		 * so ignore those first few inodes.
+		 */
+		ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
+		if (EXT3_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
+		    EXT3_INODE_SIZE(inode->i_sb))
+			goto bad_inode;
+		if (ei->i_extra_isize == 0) {
+			/* The extra space is currently unused. Use it. */
+			ei->i_extra_isize = sizeof(struct ext3_inode) -
+					    EXT3_GOOD_OLD_INODE_SIZE;
+		} else {
+			__le32 *magic = (void *)raw_inode +
+					EXT3_GOOD_OLD_INODE_SIZE +
+					ei->i_extra_isize;
+			if (*magic == cpu_to_le32(EXT3_XATTR_MAGIC))
+				 ei->i_state |= EXT3_STATE_XATTR;
+		}
+	} else
+		ei->i_extra_isize = 0;
+
+	if (S_ISREG(inode->i_mode)) {
+		inode->i_op = &ext3_file_inode_operations;
+		inode->i_fop = &ext3_file_operations;
+		ext3_set_aops(inode);
+	} else if (S_ISDIR(inode->i_mode)) {
+		inode->i_op = &ext3_dir_inode_operations;
+		inode->i_fop = &ext3_dir_operations;
+	} else if (S_ISLNK(inode->i_mode)) {
+		if (ext3_inode_is_fast_symlink(inode))
+			inode->i_op = &ext3_fast_symlink_inode_operations;
+		else {
+			inode->i_op = &ext3_symlink_inode_operations;
+			ext3_set_aops(inode);
+		}
+	} else {
+		inode->i_op = &ext3_special_inode_operations;
+		if (raw_inode->i_block[0])
+			init_special_inode(inode, inode->i_mode,
+			   old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
+		else
+			init_special_inode(inode, inode->i_mode,
+			   new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
+	}
+	brelse (iloc.bh);
+	ext3_set_inode_flags(inode);
+	return;
+
+bad_inode:
+	make_bad_inode(inode);
+	return;
+}
+
+/*
+ * Post the struct inode info into an on-disk inode location in the
+ * buffer-cache.  This gobbles the caller's reference to the
+ * buffer_head in the inode location struct.
+ *
+ * The caller must have write access to iloc->bh.
+ */
+static int ext3_do_update_inode(handle_t *handle,
+				struct inode *inode,
+				struct ext3_iloc *iloc)
+{
+	struct ext3_inode *raw_inode = ext3_raw_inode(iloc);
+	struct ext3_inode_info *ei = EXT3_I(inode);
+	struct buffer_head *bh = iloc->bh;
+	int err = 0, rc, block;
+
+	/* For fields not not tracking in the in-memory inode,
+	 * initialise them to zero for new inodes. */
+	if (ei->i_state & EXT3_STATE_NEW)
+		memset(raw_inode, 0, EXT3_SB(inode->i_sb)->s_inode_size);
+
+	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
+	if(!(test_opt(inode->i_sb, NO_UID32))) {
+		raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
+		raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
+/*
+ * Fix up interoperability with old kernels. Otherwise, old inodes get
+ * re-used with the upper 16 bits of the uid/gid intact
+ */
+		if(!ei->i_dtime) {
+			raw_inode->i_uid_high =
+				cpu_to_le16(high_16_bits(inode->i_uid));
+			raw_inode->i_gid_high =
+				cpu_to_le16(high_16_bits(inode->i_gid));
+		} else {
+			raw_inode->i_uid_high = 0;
+			raw_inode->i_gid_high = 0;
+		}
+	} else {
+		raw_inode->i_uid_low =
+			cpu_to_le16(fs_high2lowuid(inode->i_uid));
+		raw_inode->i_gid_low =
+			cpu_to_le16(fs_high2lowgid(inode->i_gid));
+		raw_inode->i_uid_high = 0;
+		raw_inode->i_gid_high = 0;
+	}
+	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
+	raw_inode->i_size = cpu_to_le32(ei->i_disksize);
+	raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
+	raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
+	raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
+	raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
+	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
+	raw_inode->i_flags = cpu_to_le32(ei->i_flags);
+#ifdef EXT3_FRAGMENTS
+	raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
+	raw_inode->i_frag = ei->i_frag_no;
+	raw_inode->i_fsize = ei->i_frag_size;
+#endif
+	raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
+	if (!S_ISREG(inode->i_mode)) {
+		raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
+	} else {
+		raw_inode->i_size_high =
+			cpu_to_le32(ei->i_disksize >> 32);
+		if (ei->i_disksize > 0x7fffffffULL) {
+			struct super_block *sb = inode->i_sb;
+			if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
+					EXT3_FEATURE_RO_COMPAT_LARGE_FILE) ||
+			    EXT3_SB(sb)->s_es->s_rev_level ==
+					cpu_to_le32(EXT3_GOOD_OLD_REV)) {
+			       /* If this is the first large file
+				* created, add a flag to the superblock.
+				*/
+				err = ext3_journal_get_write_access(handle,
+						EXT3_SB(sb)->s_sbh);
+				if (err)
+					goto out_brelse;
+				ext3_update_dynamic_rev(sb);
+				EXT3_SET_RO_COMPAT_FEATURE(sb,
+					EXT3_FEATURE_RO_COMPAT_LARGE_FILE);
+				sb->s_dirt = 1;
+				handle->h_sync = 1;
+				err = ext3_journal_dirty_metadata(handle,
+						EXT3_SB(sb)->s_sbh);
+			}
+		}
+	}
+	raw_inode->i_generation = cpu_to_le32(inode->i_generation);
+	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
+		if (old_valid_dev(inode->i_rdev)) {
+			raw_inode->i_block[0] =
+				cpu_to_le32(old_encode_dev(inode->i_rdev));
+			raw_inode->i_block[1] = 0;
+		} else {
+			raw_inode->i_block[0] = 0;
+			raw_inode->i_block[1] =
+				cpu_to_le32(new_encode_dev(inode->i_rdev));
+			raw_inode->i_block[2] = 0;
+		}
+	} else for (block = 0; block < EXT3_N_BLOCKS; block++)
+		raw_inode->i_block[block] = ei->i_data[block];
+
+	if (ei->i_extra_isize)
+		raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
+
+	BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
+	rc = ext3_journal_dirty_metadata(handle, bh);
+	if (!err)
+		err = rc;
+	ei->i_state &= ~EXT3_STATE_NEW;
+
+out_brelse:
+	brelse (bh);
+	ext3_std_error(inode->i_sb, err);
+	return err;
+}
+
+/*
+ * ext3_write_inode()
+ *
+ * We are called from a few places:
+ *
+ * - Within generic_file_write() for O_SYNC files.
+ *   Here, there will be no transaction running. We wait for any running
+ *   trasnaction to commit.
+ *
+ * - Within sys_sync(), kupdate and such.
+ *   We wait on commit, if tol to.
+ *
+ * - Within prune_icache() (PF_MEMALLOC == true)
+ *   Here we simply return.  We can't afford to block kswapd on the
+ *   journal commit.
+ *
+ * In all cases it is actually safe for us to return without doing anything,
+ * because the inode has been copied into a raw inode buffer in
+ * ext3_mark_inode_dirty().  This is a correctness thing for O_SYNC and for
+ * knfsd.
+ *
+ * Note that we are absolutely dependent upon all inode dirtiers doing the
+ * right thing: they *must* call mark_inode_dirty() after dirtying info in
+ * which we are interested.
+ *
+ * It would be a bug for them to not do this.  The code:
+ *
+ *	mark_inode_dirty(inode)
+ *	stuff();
+ *	inode->i_size = expr;
+ *
+ * is in error because a kswapd-driven write_inode() could occur while
+ * `stuff()' is running, and the new i_size will be lost.  Plus the inode
+ * will no longer be on the superblock's dirty inode list.
+ */
+int ext3_write_inode(struct inode *inode, int wait)
+{
+	if (current->flags & PF_MEMALLOC)
+		return 0;
+
+	if (ext3_journal_current_handle()) {
+		jbd_debug(0, "called recursively, non-PF_MEMALLOC!\n");
+		dump_stack();
+		return -EIO;
+	}
+
+	if (!wait)
+		return 0;
+
+	return ext3_force_commit(inode->i_sb);
+}
+
+/*
+ * ext3_setattr()
+ *
+ * Called from notify_change.
+ *
+ * We want to trap VFS attempts to truncate the file as soon as
+ * possible.  In particular, we want to make sure that when the VFS
+ * shrinks i_size, we put the inode on the orphan list and modify
+ * i_disksize immediately, so that during the subsequent flushing of
+ * dirty pages and freeing of disk blocks, we can guarantee that any
+ * commit will leave the blocks being flushed in an unused state on
+ * disk.  (On recovery, the inode will get truncated and the blocks will
+ * be freed, so we have a strong guarantee that no future commit will
+ * leave these blocks visible to the user.)
+ *
+ * Called with inode->sem down.
+ */
+int ext3_setattr(struct dentry *dentry, struct iattr *attr)
+{
+	struct inode *inode = dentry->d_inode;
+	int error, rc = 0;
+	const unsigned int ia_valid = attr->ia_valid;
+
+	error = inode_change_ok(inode, attr);
+	if (error)
+		return error;
+
+	if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
+		(ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
+		handle_t *handle;
+
+		/* (user+group)*(old+new) structure, inode write (sb,
+		 * inode block, ? - but truncate inode update has it) */
+		handle = ext3_journal_start(inode, 2*(EXT3_QUOTA_INIT_BLOCKS(inode->i_sb)+
+					EXT3_QUOTA_DEL_BLOCKS(inode->i_sb))+3);
+		if (IS_ERR(handle)) {
+			error = PTR_ERR(handle);
+			goto err_out;
+		}
+		error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
+		if (error) {
+			ext3_journal_stop(handle);
+			return error;
+		}
+		/* Update corresponding info in inode so that everything is in
+		 * one transaction */
+		if (attr->ia_valid & ATTR_UID)
+			inode->i_uid = attr->ia_uid;
+		if (attr->ia_valid & ATTR_GID)
+			inode->i_gid = attr->ia_gid;
+		error = ext3_mark_inode_dirty(handle, inode);
+		ext3_journal_stop(handle);
+	}
+
+	if (S_ISREG(inode->i_mode) &&
+	    attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
+		handle_t *handle;
+
+		handle = ext3_journal_start(inode, 3);
+		if (IS_ERR(handle)) {
+			error = PTR_ERR(handle);
+			goto err_out;
+		}
+
+		error = ext3_orphan_add(handle, inode);
+		EXT3_I(inode)->i_disksize = attr->ia_size;
+		rc = ext3_mark_inode_dirty(handle, inode);
+		if (!error)
+			error = rc;
+		ext3_journal_stop(handle);
+	}
+
+	rc = inode_setattr(inode, attr);
+
+	/* If inode_setattr's call to ext3_truncate failed to get a
+	 * transaction handle at all, we need to clean up the in-core
+	 * orphan list manually. */
+	if (inode->i_nlink)
+		ext3_orphan_del(NULL, inode);
+
+	if (!rc && (ia_valid & ATTR_MODE))
+		rc = ext3_acl_chmod(inode);
+
+err_out:
+	ext3_std_error(inode->i_sb, error);
+	if (!error)
+		error = rc;
+	return error;
+}
+
+
+/*
+ * How many blocks doth make a writepage()?
+ *
+ * With N blocks per page, it may be:
+ * N data blocks
+ * 2 indirect block
+ * 2 dindirect
+ * 1 tindirect
+ * N+5 bitmap blocks (from the above)
+ * N+5 group descriptor summary blocks
+ * 1 inode block
+ * 1 superblock.
+ * 2 * EXT3_SINGLEDATA_TRANS_BLOCKS for the quote files
+ *
+ * 3 * (N + 5) + 2 + 2 * EXT3_SINGLEDATA_TRANS_BLOCKS
+ *
+ * With ordered or writeback data it's the same, less the N data blocks.
+ *
+ * If the inode's direct blocks can hold an integral number of pages then a
+ * page cannot straddle two indirect blocks, and we can only touch one indirect
+ * and dindirect block, and the "5" above becomes "3".
+ *
+ * This still overestimates under most circumstances.  If we were to pass the
+ * start and end offsets in here as well we could do block_to_path() on each
+ * block and work out the exact number of indirects which are touched.  Pah.
+ */
+
+static int ext3_writepage_trans_blocks(struct inode *inode)
+{
+	int bpp = ext3_journal_blocks_per_page(inode);
+	int indirects = (EXT3_NDIR_BLOCKS % bpp) ? 5 : 3;
+	int ret;
+
+	if (ext3_should_journal_data(inode))
+		ret = 3 * (bpp + indirects) + 2;
+	else
+		ret = 2 * (bpp + indirects) + 2;
+
+#ifdef CONFIG_QUOTA
+	/* We know that structure was already allocated during DQUOT_INIT so
+	 * we will be updating only the data blocks + inodes */
+	ret += 2*EXT3_QUOTA_TRANS_BLOCKS(inode->i_sb);
+#endif
+
+	return ret;
+}
+
+/*
+ * The caller must have previously called ext3_reserve_inode_write().
+ * Give this, we know that the caller already has write access to iloc->bh.
+ */
+int ext3_mark_iloc_dirty(handle_t *handle,
+		struct inode *inode, struct ext3_iloc *iloc)
+{
+	int err = 0;
+
+	/* the do_update_inode consumes one bh->b_count */
+	get_bh(iloc->bh);
+
+	/* ext3_do_update_inode() does journal_dirty_metadata */
+	err = ext3_do_update_inode(handle, inode, iloc);
+	put_bh(iloc->bh);
+	return err;
+}
+
+/*
+ * On success, We end up with an outstanding reference count against
+ * iloc->bh.  This _must_ be cleaned up later.
+ */
+
+int
+ext3_reserve_inode_write(handle_t *handle, struct inode *inode,
+			 struct ext3_iloc *iloc)
+{
+	int err = 0;
+	if (handle) {
+		err = ext3_get_inode_loc(inode, iloc);
+		if (!err) {
+			BUFFER_TRACE(iloc->bh, "get_write_access");
+			err = ext3_journal_get_write_access(handle, iloc->bh);
+			if (err) {
+				brelse(iloc->bh);
+				iloc->bh = NULL;
+			}
+		}
+	}
+	ext3_std_error(inode->i_sb, err);
+	return err;
+}
+
+/*
+ * What we do here is to mark the in-core inode as clean with respect to inode
+ * dirtiness (it may still be data-dirty).
+ * This means that the in-core inode may be reaped by prune_icache
+ * without having to perform any I/O.  This is a very good thing,
+ * because *any* task may call prune_icache - even ones which
+ * have a transaction open against a different journal.
+ *
+ * Is this cheating?  Not really.  Sure, we haven't written the
+ * inode out, but prune_icache isn't a user-visible syncing function.
+ * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
+ * we start and wait on commits.
+ *
+ * Is this efficient/effective?  Well, we're being nice to the system
+ * by cleaning up our inodes proactively so they can be reaped
+ * without I/O.  But we are potentially leaving up to five seconds'
+ * worth of inodes floating about which prune_icache wants us to
+ * write out.  One way to fix that would be to get prune_icache()
+ * to do a write_super() to free up some memory.  It has the desired
+ * effect.
+ */
+int ext3_mark_inode_dirty(handle_t *handle, struct inode *inode)
+{
+	struct ext3_iloc iloc;
+	int err;
+
+	might_sleep();
+	err = ext3_reserve_inode_write(handle, inode, &iloc);
+	if (!err)
+		err = ext3_mark_iloc_dirty(handle, inode, &iloc);
+	return err;
+}
+
+/*
+ * ext3_dirty_inode() is called from __mark_inode_dirty()
+ *
+ * We're really interested in the case where a file is being extended.
+ * i_size has been changed by generic_commit_write() and we thus need
+ * to include the updated inode in the current transaction.
+ *
+ * Also, DQUOT_ALLOC_SPACE() will always dirty the inode when blocks
+ * are allocated to the file.
+ *
+ * If the inode is marked synchronous, we don't honour that here - doing
+ * so would cause a commit on atime updates, which we don't bother doing.
+ * We handle synchronous inodes at the highest possible level.
+ */
+void ext3_dirty_inode(struct inode *inode)
+{
+	handle_t *current_handle = ext3_journal_current_handle();
+	handle_t *handle;
+
+	handle = ext3_journal_start(inode, 2);
+	if (IS_ERR(handle))
+		goto out;
+	if (current_handle &&
+		current_handle->h_transaction != handle->h_transaction) {
+		/* This task has a transaction open against a different fs */
+		printk(KERN_EMERG "%s: transactions do not match!\n",
+		       __FUNCTION__);
+	} else {
+		jbd_debug(5, "marking dirty.  outer handle=%p\n",
+				current_handle);
+		ext3_mark_inode_dirty(handle, inode);
+	}
+	ext3_journal_stop(handle);
+out:
+	return;
+}
+
+#if 0
+/*
+ * Bind an inode's backing buffer_head into this transaction, to prevent
+ * it from being flushed to disk early.  Unlike
+ * ext3_reserve_inode_write, this leaves behind no bh reference and
+ * returns no iloc structure, so the caller needs to repeat the iloc
+ * lookup to mark the inode dirty later.
+ */
+static int ext3_pin_inode(handle_t *handle, struct inode *inode)
+{
+	struct ext3_iloc iloc;
+
+	int err = 0;
+	if (handle) {
+		err = ext3_get_inode_loc(inode, &iloc);
+		if (!err) {
+			BUFFER_TRACE(iloc.bh, "get_write_access");
+			err = journal_get_write_access(handle, iloc.bh);
+			if (!err)
+				err = ext3_journal_dirty_metadata(handle,
+								  iloc.bh);
+			brelse(iloc.bh);
+		}
+	}
+	ext3_std_error(inode->i_sb, err);
+	return err;
+}
+#endif
+
+int ext3_change_inode_journal_flag(struct inode *inode, int val)
+{
+	journal_t *journal;
+	handle_t *handle;
+	int err;
+
+	/*
+	 * We have to be very careful here: changing a data block's
+	 * journaling status dynamically is dangerous.  If we write a
+	 * data block to the journal, change the status and then delete
+	 * that block, we risk forgetting to revoke the old log record
+	 * from the journal and so a subsequent replay can corrupt data.
+	 * So, first we make sure that the journal is empty and that
+	 * nobody is changing anything.
+	 */
+
+	journal = EXT3_JOURNAL(inode);
+	if (is_journal_aborted(journal) || IS_RDONLY(inode))
+		return -EROFS;
+
+	journal_lock_updates(journal);
+	journal_flush(journal);
+
+	/*
+	 * OK, there are no updates running now, and all cached data is
+	 * synced to disk.  We are now in a completely consistent state
+	 * which doesn't have anything in the journal, and we know that
+	 * no filesystem updates are running, so it is safe to modify
+	 * the inode's in-core data-journaling state flag now.
+	 */
+
+	if (val)
+		EXT3_I(inode)->i_flags |= EXT3_JOURNAL_DATA_FL;
+	else
+		EXT3_I(inode)->i_flags &= ~EXT3_JOURNAL_DATA_FL;
+	ext3_set_aops(inode);
+
+	journal_unlock_updates(journal);
+
+	/* Finally we can mark the inode as dirty. */
+
+	handle = ext3_journal_start(inode, 1);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	err = ext3_mark_inode_dirty(handle, inode);
+	handle->h_sync = 1;
+	ext3_journal_stop(handle);
+	ext3_std_error(inode->i_sb, err);
+
+	return err;
+}

fs/ext4/ioctl.c

+/*
+ * linux/fs/ext3/ioctl.c
+ *
+ * Copyright (C) 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ */
+
+#include <linux/fs.h>
+#include <linux/jbd.h>
+#include <linux/capability.h>
+#include <linux/ext3_fs.h>
+#include <linux/ext3_jbd.h>
+#include <linux/time.h>
+#include <linux/compat.h>
+#include <linux/smp_lock.h>
+#include <asm/uaccess.h>
+
+int ext3_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
+		unsigned long arg)
+{
+	struct ext3_inode_info *ei = EXT3_I(inode);
+	unsigned int flags;
+	unsigned short rsv_window_size;
+
+	ext3_debug ("cmd = %u, arg = %lu\n", cmd, arg);
+
+	switch (cmd) {
+	case EXT3_IOC_GETFLAGS:
+		flags = ei->i_flags & EXT3_FL_USER_VISIBLE;
+		return put_user(flags, (int __user *) arg);
+	case EXT3_IOC_SETFLAGS: {
+		handle_t *handle = NULL;
+		int err;
+		struct ext3_iloc iloc;
+		unsigned int oldflags;
+		unsigned int jflag;
+
+		if (IS_RDONLY(inode))
+			return -EROFS;
+
+		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
+			return -EACCES;
+
+		if (get_user(flags, (int __user *) arg))
+			return -EFAULT;
+
+		if (!S_ISDIR(inode->i_mode))
+			flags &= ~EXT3_DIRSYNC_FL;
+
+		mutex_lock(&inode->i_mutex);
+		oldflags = ei->i_flags;
+
+		/* The JOURNAL_DATA flag is modifiable only by root */
+		jflag = flags & EXT3_JOURNAL_DATA_FL;
+
+		/*
+		 * The IMMUTABLE and APPEND_ONLY flags can only be changed by
+		 * the relevant capability.
+		 *
+		 * This test looks nicer. Thanks to Pauline Middelink
+		 */
+		if ((flags ^ oldflags) & (EXT3_APPEND_FL | EXT3_IMMUTABLE_FL)) {
+			if (!capable(CAP_LINUX_IMMUTABLE)) {
+				mutex_unlock(&inode->i_mutex);
+				return -EPERM;
+			}
+		}
+
+		/*
+		 * The JOURNAL_DATA flag can only be changed by
+		 * the relevant capability.
+		 */
+		if ((jflag ^ oldflags) & (EXT3_JOURNAL_DATA_FL)) {
+			if (!capable(CAP_SYS_RESOURCE)) {
+				mutex_unlock(&inode->i_mutex);
+				return -EPERM;
+			}
+		}
+
+
+		handle = ext3_journal_start(inode, 1);
+		if (IS_ERR(handle)) {
+			mutex_unlock(&inode->i_mutex);
+			return PTR_ERR(handle);
+		}
+		if (IS_SYNC(inode))
+			handle->h_sync = 1;
+		err = ext3_reserve_inode_write(handle, inode, &iloc);
+		if (err)
+			goto flags_err;
+
+		flags = flags & EXT3_FL_USER_MODIFIABLE;
+		flags |= oldflags & ~EXT3_FL_USER_MODIFIABLE;
+		ei->i_flags = flags;
+
+		ext3_set_inode_flags(inode);
+		inode->i_ctime = CURRENT_TIME_SEC;
+
+		err = ext3_mark_iloc_dirty(handle, inode, &iloc);
+flags_err:
+		ext3_journal_stop(handle);
+		if (err) {
+			mutex_unlock(&inode->i_mutex);
+			return err;
+		}
+
+		if ((jflag ^ oldflags) & (EXT3_JOURNAL_DATA_FL))
+			err = ext3_change_inode_journal_flag(inode, jflag);
+		mutex_unlock(&inode->i_mutex);
+		return err;
+	}
+	case EXT3_IOC_GETVERSION:
+	case EXT3_IOC_GETVERSION_OLD:
+		return put_user(inode->i_generation, (int __user *) arg);
+	case EXT3_IOC_SETVERSION:
+	case EXT3_IOC_SETVERSION_OLD: {
+		handle_t *handle;
+		struct ext3_iloc iloc;
+		__u32 generation;
+		int err;
+
+		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
+			return -EPERM;
+		if (IS_RDONLY(inode))
+			return -EROFS;
+		if (get_user(generation, (int __user *) arg))
+			return -EFAULT;
+
+		handle = ext3_journal_start(inode, 1);
+		if (IS_ERR(handle))
+			return PTR_ERR(handle);
+		err = ext3_reserve_inode_write(handle, inode, &iloc);
+		if (err == 0) {
+			inode->i_ctime = CURRENT_TIME_SEC;
+			inode->i_generation = generation;
+			err = ext3_mark_iloc_dirty(handle, inode, &iloc);
+		}
+		ext3_journal_stop(handle);
+		return err;
+	}
+#ifdef CONFIG_JBD_DEBUG
+	case EXT3_IOC_WAIT_FOR_READONLY:
+		/*
+		 * This is racy - by the time we're woken up and running,
+		 * the superblock could be released.  And the module could
+		 * have been unloaded.  So sue me.
+		 *
+		 * Returns 1 if it slept, else zero.
+		 */
+		{
+			struct super_block *sb = inode->i_sb;
+			DECLARE_WAITQUEUE(wait, current);
+			int ret = 0;
+
+			set_current_state(TASK_INTERRUPTIBLE);
+			add_wait_queue(&EXT3_SB(sb)->ro_wait_queue, &wait);
+			if (timer_pending(&EXT3_SB(sb)->turn_ro_timer)) {
+				schedule();
+				ret = 1;
+			}
+			remove_wait_queue(&EXT3_SB(sb)->ro_wait_queue, &wait);
+			return ret;
+		}
+#endif
+	case EXT3_IOC_GETRSVSZ:
+		if (test_opt(inode->i_sb, RESERVATION)
+			&& S_ISREG(inode->i_mode)
+			&& ei->i_block_alloc_info) {
+			rsv_window_size = ei->i_block_alloc_info->rsv_window_node.rsv_goal_size;
+			return put_user(rsv_window_size, (int __user *)arg);
+		}
+		return -ENOTTY;
+	case EXT3_IOC_SETRSVSZ: {
+
+		if (!test_opt(inode->i_sb, RESERVATION) ||!S_ISREG(inode->i_mode))
+			return -ENOTTY;
+
+		if (IS_RDONLY(inode))
+			return -EROFS;
+
+		if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
+			return -EACCES;
+
+		if (get_user(rsv_window_size, (int __user *)arg))
+			return -EFAULT;
+
+		if (rsv_window_size > EXT3_MAX_RESERVE_BLOCKS)
+			rsv_window_size = EXT3_MAX_RESERVE_BLOCKS;
+
+		/*
+		 * need to allocate reservation structure for this inode
+		 * before set the window size
+		 */
+		mutex_lock(&ei->truncate_mutex);
+		if (!ei->i_block_alloc_info)
+			ext3_init_block_alloc_info(inode);
+
+		if (ei->i_block_alloc_info){
+			struct ext3_reserve_window_node *rsv = &ei->i_block_alloc_info->rsv_window_node;
+			rsv->rsv_goal_size = rsv_window_size;
+		}
+		mutex_unlock(&ei->truncate_mutex);
+		return 0;
+	}
+	case EXT3_IOC_GROUP_EXTEND: {
+		ext3_fsblk_t n_blocks_count;
+		struct super_block *sb = inode->i_sb;
+		int err;
+
+		if (!capable(CAP_SYS_RESOURCE))
+			return -EPERM;
+
+		if (IS_RDONLY(inode))
+			return -EROFS;
+
+		if (get_user(n_blocks_count, (__u32 __user *)arg))
+			return -EFAULT;
+
+		err = ext3_group_extend(sb, EXT3_SB(sb)->s_es, n_blocks_count);
+		journal_lock_updates(EXT3_SB(sb)->s_journal);
+		journal_flush(EXT3_SB(sb)->s_journal);
+		journal_unlock_updates(EXT3_SB(sb)->s_journal);
+
+		return err;
+	}
+	case EXT3_IOC_GROUP_ADD: {
+		struct ext3_new_group_data input;
+		struct super_block *sb = inode->i_sb;
+		int err;
+
+		if (!capable(CAP_SYS_RESOURCE))
+			return -EPERM;
+
+		if (IS_RDONLY(inode))
+			return -EROFS;
+
+		if (copy_from_user(&input, (struct ext3_new_group_input __user *)arg,
+				sizeof(input)))
+			return -EFAULT;
+
+		err = ext3_group_add(sb, &input);
+		journal_lock_updates(EXT3_SB(sb)->s_journal);
+		journal_flush(EXT3_SB(sb)->s_journal);
+		journal_unlock_updates(EXT3_SB(sb)->s_journal);
+
+		return err;
+	}
+
+
+	default:
+		return -ENOTTY;
+	}
+}
+
+#ifdef CONFIG_COMPAT
+long ext3_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct inode *inode = file->f_dentry->d_inode;
+	int ret;
+
+	/* These are just misnamed, they actually get/put from/to user an int */
+	switch (cmd) {
+	case EXT3_IOC32_GETFLAGS:
+		cmd = EXT3_IOC_GETFLAGS;
+		break;
+	case EXT3_IOC32_SETFLAGS:
+		cmd = EXT3_IOC_SETFLAGS;
+		break;
+	case EXT3_IOC32_GETVERSION:
+		cmd = EXT3_IOC_GETVERSION;
+		break;
+	case EXT3_IOC32_SETVERSION:
+		cmd = EXT3_IOC_SETVERSION;
+		break;
+	case EXT3_IOC32_GROUP_EXTEND:
+		cmd = EXT3_IOC_GROUP_EXTEND;
+		break;
+	case EXT3_IOC32_GETVERSION_OLD:
+		cmd = EXT3_IOC_GETVERSION_OLD;
+		break;
+	case EXT3_IOC32_SETVERSION_OLD:
+		cmd = EXT3_IOC_SETVERSION_OLD;
+		break;
+#ifdef CONFIG_JBD_DEBUG
+	case EXT3_IOC32_WAIT_FOR_READONLY:
+		cmd = EXT3_IOC_WAIT_FOR_READONLY;
+		break;
+#endif
+	case EXT3_IOC32_GETRSVSZ:
+		cmd = EXT3_IOC_GETRSVSZ;
+		break;
+	case EXT3_IOC32_SETRSVSZ:
+		cmd = EXT3_IOC_SETRSVSZ;
+		break;
+	case EXT3_IOC_GROUP_ADD:
+		break;
+	default:
+		return -ENOIOCTLCMD;
+	}
+	lock_kernel();
+	ret = ext3_ioctl(inode, file, cmd, (unsigned long) compat_ptr(arg));
+	unlock_kernel();
+	return ret;
+}
+#endif

fs/ext4/namei.c

+/*
+ *  linux/fs/ext3/namei.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/namei.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ *  Directory entry file type support and forward compatibility hooks
+ *	for B-tree directories by Theodore Ts'o (tytso@mit.edu), 1998
+ *  Hash Tree Directory indexing (c)
+ *	Daniel Phillips, 2001
+ *  Hash Tree Directory indexing porting
+ *	Christopher Li, 2002
+ *  Hash Tree Directory indexing cleanup
+ *	Theodore Ts'o, 2002
+ */
+
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/jbd.h>
+#include <linux/time.h>
+#include <linux/ext3_fs.h>
+#include <linux/ext3_jbd.h>
+#include <linux/fcntl.h>
+#include <linux/stat.h>
+#include <linux/string.h>
+#include <linux/quotaops.h>
+#include <linux/buffer_head.h>
+#include <linux/bio.h>
+#include <linux/smp_lock.h>
+
+#include "namei.h"
+#include "xattr.h"
+#include "acl.h"
+
+/*
+ * define how far ahead to read directories while searching them.
+ */
+#define NAMEI_RA_CHUNKS  2
+#define NAMEI_RA_BLOCKS  4
+#define NAMEI_RA_SIZE        (NAMEI_RA_CHUNKS * NAMEI_RA_BLOCKS)
+#define NAMEI_RA_INDEX(c,b)  (((c) * NAMEI_RA_BLOCKS) + (b))
+
+static struct buffer_head *ext3_append(handle_t *handle,
+					struct inode *inode,
+					u32 *block, int *err)
+{
+	struct buffer_head *bh;
+
+	*block = inode->i_size >> inode->i_sb->s_blocksize_bits;
+
+	if ((bh = ext3_bread(handle, inode, *block, 1, err))) {
+		inode->i_size += inode->i_sb->s_blocksize;
+		EXT3_I(inode)->i_disksize = inode->i_size;
+		ext3_journal_get_write_access(handle,bh);
+	}
+	return bh;
+}
+
+#ifndef assert
+#define assert(test) J_ASSERT(test)
+#endif
+
+#ifndef swap
+#define swap(x, y) do { typeof(x) z = x; x = y; y = z; } while (0)
+#endif
+
+#ifdef DX_DEBUG
+#define dxtrace(command) command
+#else
+#define dxtrace(command)
+#endif
+
+struct fake_dirent
+{
+	__le32 inode;
+	__le16 rec_len;
+	u8 name_len;
+	u8 file_type;
+};
+
+struct dx_countlimit
+{
+	__le16 limit;
+	__le16 count;
+};
+
+struct dx_entry
+{
+	__le32 hash;
+	__le32 block;
+};
+
+/*
+ * dx_root_info is laid out so that if it should somehow get overlaid by a
+ * dirent the two low bits of the hash version will be zero.  Therefore, the
+ * hash version mod 4 should never be 0.  Sincerely, the paranoia department.
+ */
+
+struct dx_root
+{
+	struct fake_dirent dot;
+	char dot_name[4];
+	struct fake_dirent dotdot;
+	char dotdot_name[4];
+	struct dx_root_info
+	{
+		__le32 reserved_zero;
+		u8 hash_version;
+		u8 info_length; /* 8 */
+		u8 indirect_levels;
+		u8 unused_flags;
+	}
+	info;
+	struct dx_entry	entries[0];
+};
+
+struct dx_node
+{
+	struct fake_dirent fake;
+	struct dx_entry	entries[0];
+};
+
+
+struct dx_frame
+{
+	struct buffer_head *bh;
+	struct dx_entry *entries;
+	struct dx_entry *at;
+};
+
+struct dx_map_entry
+{
+	u32 hash;
+	u32 offs;
+};
+
+#ifdef CONFIG_EXT3_INDEX
+static inline unsigned dx_get_block (struct dx_entry *entry);
+static void dx_set_block (struct dx_entry *entry, unsigned value);
+static inline unsigned dx_get_hash (struct dx_entry *entry);
+static void dx_set_hash (struct dx_entry *entry, unsigned value);
+static unsigned dx_get_count (struct dx_entry *entries);
+static unsigned dx_get_limit (struct dx_entry *entries);
+static void dx_set_count (struct dx_entry *entries, unsigned value);
+static void dx_set_limit (struct dx_entry *entries, unsigned value);
+static unsigned dx_root_limit (struct inode *dir, unsigned infosize);
+static unsigned dx_node_limit (struct inode *dir);
+static struct dx_frame *dx_probe(struct dentry *dentry,
+				 struct inode *dir,
+				 struct dx_hash_info *hinfo,
+				 struct dx_frame *frame,
+				 int *err);
+static void dx_release (struct dx_frame *frames);
+static int dx_make_map (struct ext3_dir_entry_2 *de, int size,
+			struct dx_hash_info *hinfo, struct dx_map_entry map[]);
+static void dx_sort_map(struct dx_map_entry *map, unsigned count);
+static struct ext3_dir_entry_2 *dx_move_dirents (char *from, char *to,
+		struct dx_map_entry *offsets, int count);
+static struct ext3_dir_entry_2* dx_pack_dirents (char *base, int size);
+static void dx_insert_block (struct dx_frame *frame, u32 hash, u32 block);
+static int ext3_htree_next_block(struct inode *dir, __u32 hash,
+				 struct dx_frame *frame,
+				 struct dx_frame *frames,
+				 __u32 *start_hash);
+static struct buffer_head * ext3_dx_find_entry(struct dentry *dentry,
+		       struct ext3_dir_entry_2 **res_dir, int *err);
+static int ext3_dx_add_entry(handle_t *handle, struct dentry *dentry,
+			     struct inode *inode);
+
+/*
+ * Future: use high four bits of block for coalesce-on-delete flags
+ * Mask them off for now.
+ */
+
+static inline unsigned dx_get_block (struct dx_entry *entry)
+{
+	return le32_to_cpu(entry->block) & 0x00ffffff;
+}
+
+static inline void dx_set_block (struct dx_entry *entry, unsigned value)
+{
+	entry->block = cpu_to_le32(value);
+}
+
+static inline unsigned dx_get_hash (struct dx_entry *entry)
+{
+	return le32_to_cpu(entry->hash);
+}
+
+static inline void dx_set_hash (struct dx_entry *entry, unsigned value)
+{
+	entry->hash = cpu_to_le32(value);
+}
+
+static inline unsigned dx_get_count (struct dx_entry *entries)
+{
+	return le16_to_cpu(((struct dx_countlimit *) entries)->count);
+}
+
+static inline unsigned dx_get_limit (struct dx_entry *entries)
+{
+	return le16_to_cpu(((struct dx_countlimit *) entries)->limit);
+}
+
+static inline void dx_set_count (struct dx_entry *entries, unsigned value)
+{
+	((struct dx_countlimit *) entries)->count = cpu_to_le16(value);
+}
+
+static inline void dx_set_limit (struct dx_entry *entries, unsigned value)
+{
+	((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
+}
+
+static inline unsigned dx_root_limit (struct inode *dir, unsigned infosize)
+{
+	unsigned entry_space = dir->i_sb->s_blocksize - EXT3_DIR_REC_LEN(1) -
+		EXT3_DIR_REC_LEN(2) - infosize;
+	return 0? 20: entry_space / sizeof(struct dx_entry);
+}
+
+static inline unsigned dx_node_limit (struct inode *dir)
+{
+	unsigned entry_space = dir->i_sb->s_blocksize - EXT3_DIR_REC_LEN(0);
+	return 0? 22: entry_space / sizeof(struct dx_entry);
+}
+
+/*
+ * Debug
+ */
+#ifdef DX_DEBUG
+static void dx_show_index (char * label, struct dx_entry *entries)
+{
+        int i, n = dx_get_count (entries);
+        printk("%s index ", label);
+        for (i = 0; i < n; i++)
+        {
+                printk("%x->%u ", i? dx_get_hash(entries + i): 0, dx_get_block(entries + i));
+        }
+        printk("\n");
+}
+
+struct stats
+{
+	unsigned names;
+	unsigned space;
+	unsigned bcount;
+};
+
+static struct stats dx_show_leaf(struct dx_hash_info *hinfo, struct ext3_dir_entry_2 *de,
+				 int size, int show_names)
+{
+	unsigned names = 0, space = 0;
+	char *base = (char *) de;
+	struct dx_hash_info h = *hinfo;
+
+	printk("names: ");
+	while ((char *) de < base + size)
+	{
+		if (de->inode)
+		{
+			if (show_names)
+			{
+				int len = de->name_len;
+				char *name = de->name;
+				while (len--) printk("%c", *name++);
+				ext3fs_dirhash(de->name, de->name_len, &h);
+				printk(":%x.%u ", h.hash,
+				       ((char *) de - base));
+			}
+			space += EXT3_DIR_REC_LEN(de->name_len);
+			names++;
+		}
+		de = (struct ext3_dir_entry_2 *) ((char *) de + le16_to_cpu(de->rec_len));
+	}
+	printk("(%i)\n", names);
+	return (struct stats) { names, space, 1 };
+}
+
+struct stats dx_show_entries(struct dx_hash_info *hinfo, struct inode *dir,
+			     struct dx_entry *entries, int levels)
+{
+	unsigned blocksize = dir->i_sb->s_blocksize;
+	unsigned count = dx_get_count (entries), names = 0, space = 0, i;
+	unsigned bcount = 0;
+	struct buffer_head *bh;
+	int err;
+	printk("%i indexed blocks...\n", count);
+	for (i = 0; i < count; i++, entries++)
+	{
+		u32 block = dx_get_block(entries), hash = i? dx_get_hash(entries): 0;
+		u32 range = i < count - 1? (dx_get_hash(entries + 1) - hash): ~hash;
+		struct stats stats;
+		printk("%s%3u:%03u hash %8x/%8x ",levels?"":"   ", i, block, hash, range);
+		if (!(bh = ext3_bread (NULL,dir, block, 0,&err))) continue;
+		stats = levels?
+		   dx_show_entries(hinfo, dir, ((struct dx_node *) bh->b_data)->entries, levels - 1):
+		   dx_show_leaf(hinfo, (struct ext3_dir_entry_2 *) bh->b_data, blocksize, 0);
+		names += stats.names;
+		space += stats.space;
+		bcount += stats.bcount;
+		brelse (bh);
+	}
+	if (bcount)
+		printk("%snames %u, fullness %u (%u%%)\n", levels?"":"   ",
+			names, space/bcount,(space/bcount)*100/blocksize);
+	return (struct stats) { names, space, bcount};
+}
+#endif /* DX_DEBUG */
+
+/*
+ * Probe for a directory leaf block to search.
+ *
+ * dx_probe can return ERR_BAD_DX_DIR, which means there was a format
+ * error in the directory index, and the caller should fall back to
+ * searching the directory normally.  The callers of dx_probe **MUST**
+ * check for this error code, and make sure it never gets reflected
+ * back to userspace.
+ */
+static struct dx_frame *
+dx_probe(struct dentry *dentry, struct inode *dir,
+	 struct dx_hash_info *hinfo, struct dx_frame *frame_in, int *err)
+{
+	unsigned count, indirect;
+	struct dx_entry *at, *entries, *p, *q, *m;
+	struct dx_root *root;
+	struct buffer_head *bh;
+	struct dx_frame *frame = frame_in;
+	u32 hash;
+
+	frame->bh = NULL;
+	if (dentry)
+		dir = dentry->d_parent->d_inode;
+	if (!(bh = ext3_bread (NULL,dir, 0, 0, err)))
+		goto fail;
+	root = (struct dx_root *) bh->b_data;
+	if (root->info.hash_version != DX_HASH_TEA &&
+	    root->info.hash_version != DX_HASH_HALF_MD4 &&
+	    root->info.hash_version != DX_HASH_LEGACY) {
+		ext3_warning(dir->i_sb, __FUNCTION__,
+			     "Unrecognised inode hash code %d",
+			     root->info.hash_version);
+		brelse(bh);
+		*err = ERR_BAD_DX_DIR;
+		goto fail;
+	}
+	hinfo->hash_version = root->info.hash_version;
+	hinfo->seed = EXT3_SB(dir->i_sb)->s_hash_seed;
+	if (dentry)
+		ext3fs_dirhash(dentry->d_name.name, dentry->d_name.len, hinfo);
+	hash = hinfo->hash;
+
+	if (root->info.unused_flags & 1) {
+		ext3_warning(dir->i_sb, __FUNCTION__,
+			     "Unimplemented inode hash flags: %#06x",
+			     root->info.unused_flags);
+		brelse(bh);
+		*err = ERR_BAD_DX_DIR;
+		goto fail;
+	}
+
+	if ((indirect = root->info.indirect_levels) > 1) {
+		ext3_warning(dir->i_sb, __FUNCTION__,
+			     "Unimplemented inode hash depth: %#06x",
+			     root->info.indirect_levels);
+		brelse(bh);
+		*err = ERR_BAD_DX_DIR;
+		goto fail;
+	}
+
+	entries = (struct dx_entry *) (((char *)&root->info) +
+				       root->info.info_length);
+	assert(dx_get_limit(entries) == dx_root_limit(dir,
+						      root->info.info_length));
+	dxtrace (printk("Look up %x", hash));
+	while (1)
+	{
+		count = dx_get_count(entries);
+		assert (count && count <= dx_get_limit(entries));
+		p = entries + 1;
+		q = entries + count - 1;
+		while (p <= q)
+		{
+			m = p + (q - p)/2;
+			dxtrace(printk("."));
+			if (dx_get_hash(m) > hash)
+				q = m - 1;
+			else
+				p = m + 1;
+		}
+
+		if (0) // linear search cross check
+		{
+			unsigned n = count - 1;
+			at = entries;
+			while (n--)
+			{
+				dxtrace(printk(","));
+				if (dx_get_hash(++at) > hash)
+				{
+					at--;
+					break;
+				}
+			}
+			assert (at == p - 1);
+		}
+
+		at = p - 1;
+		dxtrace(printk(" %x->%u\n", at == entries? 0: dx_get_hash(at), dx_get_block(at)));
+		frame->bh = bh;
+		frame->entries = entries;
+		frame->at = at;
+		if (!indirect--) return frame;
+		if (!(bh = ext3_bread (NULL,dir, dx_get_block(at), 0, err)))
+			goto fail2;
+		at = entries = ((struct dx_node *) bh->b_data)->entries;
+		assert (dx_get_limit(entries) == dx_node_limit (dir));
+		frame++;
+	}
+fail2:
+	while (frame >= frame_in) {
+		brelse(frame->bh);
+		frame--;
+	}
+fail:
+	return NULL;
+}
+
+static void dx_release (struct dx_frame *frames)
+{
+	if (frames[0].bh == NULL)
+		return;
+
+	if (((struct dx_root *) frames[0].bh->b_data)->info.indirect_levels)
+		brelse(frames[1].bh);
+	brelse(frames[0].bh);
+}
+
+/*
+ * This function increments the frame pointer to search the next leaf
+ * block, and reads in the necessary intervening nodes if the search
+ * should be necessary.  Whether or not the search is necessary is
+ * controlled by the hash parameter.  If the hash value is even, then
+ * the search is only continued if the next block starts with that
+ * hash value.  This is used if we are searching for a specific file.
+ *
+ * If the hash value is HASH_NB_ALWAYS, then always go to the next block.
+ *
+ * This function returns 1 if the caller should continue to search,
+ * or 0 if it should not.  If there is an error reading one of the
+ * index blocks, it will a negative error code.
+ *
+ * If start_hash is non-null, it will be filled in with the starting
+ * hash of the next page.
+ */
+static int ext3_htree_next_block(struct inode *dir, __u32 hash,
+				 struct dx_frame *frame,
+				 struct dx_frame *frames,
+				 __u32 *start_hash)
+{
+	struct dx_frame *p;
+	struct buffer_head *bh;
+	int err, num_frames = 0;
+	__u32 bhash;
+
+	p = frame;
+	/*
+	 * Find the next leaf page by incrementing the frame pointer.
+	 * If we run out of entries in the interior node, loop around and
+	 * increment pointer in the parent node.  When we break out of
+	 * this loop, num_frames indicates the number of interior
+	 * nodes need to be read.
+	 */
+	while (1) {
+		if (++(p->at) < p->entries + dx_get_count(p->entries))
+			break;
+		if (p == frames)
+			return 0;
+		num_frames++;
+		p--;
+	}
+
+	/*
+	 * If the hash is 1, then continue only if the next page has a
+	 * continuation hash of any value.  This is used for readdir
+	 * handling.  Otherwise, check to see if the hash matches the
+	 * desired contiuation hash.  If it doesn't, return since
+	 * there's no point to read in the successive index pages.
+	 */
+	bhash = dx_get_hash(p->at);
+	if (start_hash)
+		*start_hash = bhash;
+	if ((hash & 1) == 0) {
+		if ((bhash & ~1) != hash)
+			return 0;
+	}
+	/*
+	 * If the hash is HASH_NB_ALWAYS, we always go to the next
+	 * block so no check is necessary
+	 */
+	while (num_frames--) {
+		if (!(bh = ext3_bread(NULL, dir, dx_get_block(p->at),
+				      0, &err)))
+			return err; /* Failure */
+		p++;
+		brelse (p->bh);
+		p->bh = bh;
+		p->at = p->entries = ((struct dx_node *) bh->b_data)->entries;
+	}
+	return 1;
+}
+
+
+/*
+ * p is at least 6 bytes before the end of page
+ */
+static inline struct ext3_dir_entry_2 *ext3_next_entry(struct ext3_dir_entry_2 *p)
+{
+	return (struct ext3_dir_entry_2 *)((char*)p + le16_to_cpu(p->rec_len));
+}
+
+/*
+ * This function fills a red-black tree with information from a
+ * directory block.  It returns the number directory entries loaded
+ * into the tree.  If there is an error it is returned in err.
+ */
+static int htree_dirblock_to_tree(struct file *dir_file,
+				  struct inode *dir, int block,
+				  struct dx_hash_info *hinfo,
+				  __u32 start_hash, __u32 start_minor_hash)
+{
+	struct buffer_head *bh;
+	struct ext3_dir_entry_2 *de, *top;
+	int err, count = 0;
+
+	dxtrace(printk("In htree dirblock_to_tree: block %d\n", block));
+	if (!(bh = ext3_bread (NULL, dir, block, 0, &err)))
+		return err;
+
+	de = (struct ext3_dir_entry_2 *) bh->b_data;
+	top = (struct ext3_dir_entry_2 *) ((char *) de +
+					   dir->i_sb->s_blocksize -
+					   EXT3_DIR_REC_LEN(0));
+	for (; de < top; de = ext3_next_entry(de)) {
+		ext3fs_dirhash(de->name, de->name_len, hinfo);
+		if ((hinfo->hash < start_hash) ||
+		    ((hinfo->hash == start_hash) &&
+		     (hinfo->minor_hash < start_minor_hash)))
+			continue;
+		if (de->inode == 0)
+			continue;
+		if ((err = ext3_htree_store_dirent(dir_file,
+				   hinfo->hash, hinfo->minor_hash, de)) != 0) {
+			brelse(bh);
+			return err;
+		}
+		count++;
+	}
+	brelse(bh);
+	return count;
+}
+
+
+/*
+ * This function fills a red-black tree with information from a
+ * directory.  We start scanning the directory in hash order, starting
+ * at start_hash and start_minor_hash.
+ *
+ * This function returns the number of entries inserted into the tree,
+ * or a negative error code.
+ */
+int ext3_htree_fill_tree(struct file *dir_file, __u32 start_hash,
+			 __u32 start_minor_hash, __u32 *next_hash)
+{
+	struct dx_hash_info hinfo;
+	struct ext3_dir_entry_2 *de;
+	struct dx_frame frames[2], *frame;
+	struct inode *dir;
+	int block, err;
+	int count = 0;
+	int ret;
+	__u32 hashval;
+
+	dxtrace(printk("In htree_fill_tree, start hash: %x:%x\n", start_hash,
+		       start_minor_hash));
+	dir = dir_file->f_dentry->d_inode;
+	if (!(EXT3_I(dir)->i_flags & EXT3_INDEX_FL)) {
+		hinfo.hash_version = EXT3_SB(dir->i_sb)->s_def_hash_version;
+		hinfo.seed = EXT3_SB(dir->i_sb)->s_hash_seed;
+		count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
+					       start_hash, start_minor_hash);
+		*next_hash = ~0;
+		return count;
+	}
+	hinfo.hash = start_hash;
+	hinfo.minor_hash = 0;
+	frame = dx_probe(NULL, dir_file->f_dentry->d_inode, &hinfo, frames, &err);
+	if (!frame)
+		return err;
+
+	/* Add '.' and '..' from the htree header */
+	if (!start_hash && !start_minor_hash) {
+		de = (struct ext3_dir_entry_2 *) frames[0].bh->b_data;
+		if ((err = ext3_htree_store_dirent(dir_file, 0, 0, de)) != 0)
+			goto errout;
+		count++;
+	}
+	if (start_hash < 2 || (start_hash ==2 && start_minor_hash==0)) {
+		de = (struct ext3_dir_entry_2 *) frames[0].bh->b_data;
+		de = ext3_next_entry(de);
+		if ((err = ext3_htree_store_dirent(dir_file, 2, 0, de)) != 0)
+			goto errout;
+		count++;
+	}
+
+	while (1) {
+		block = dx_get_block(frame->at);
+		ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo,
+					     start_hash, start_minor_hash);
+		if (ret < 0) {
+			err = ret;
+			goto errout;
+		}
+		count += ret;
+		hashval = ~0;
+		ret = ext3_htree_next_block(dir, HASH_NB_ALWAYS,
+					    frame, frames, &hashval);
+		*next_hash = hashval;
+		if (ret < 0) {
+			err = ret;
+			goto errout;
+		}
+		/*
+		 * Stop if:  (a) there are no more entries, or
+		 * (b) we have inserted at least one entry and the
+		 * next hash value is not a continuation
+		 */
+		if ((ret == 0) ||
+		    (count && ((hashval & 1) == 0)))
+			break;
+	}
+	dx_release(frames);
+	dxtrace(printk("Fill tree: returned %d entries, next hash: %x\n",
+		       count, *next_hash));
+	return count;
+errout:
+	dx_release(frames);
+	return (err);
+}
+
+
+/*
+ * Directory block splitting, compacting
+ */
+
+static int dx_make_map (struct ext3_dir_entry_2 *de, int size,
+			struct dx_hash_info *hinfo, struct dx_map_entry *map_tail)
+{
+	int count = 0;
+	char *base = (char *) de;
+	struct dx_hash_info h = *hinfo;
+
+	while ((char *) de < base + size)
+	{
+		if (de->name_len && de->inode) {
+			ext3fs_dirhash(de->name, de->name_len, &h);
+			map_tail--;
+			map_tail->hash = h.hash;
+			map_tail->offs = (u32) ((char *) de - base);
+			count++;
+			cond_resched();
+		}
+		/* XXX: do we need to check rec_len == 0 case? -Chris */
+		de = (struct ext3_dir_entry_2 *) ((char *) de + le16_to_cpu(de->rec_len));
+	}
+	return count;
+}
+
+static void dx_sort_map (struct dx_map_entry *map, unsigned count)
+{
+        struct dx_map_entry *p, *q, *top = map + count - 1;
+        int more;
+        /* Combsort until bubble sort doesn't suck */
+        while (count > 2)
+	{
+                count = count*10/13;
+                if (count - 9 < 2) /* 9, 10 -> 11 */
+                        count = 11;
+                for (p = top, q = p - count; q >= map; p--, q--)
+                        if (p->hash < q->hash)
+                                swap(*p, *q);
+        }
+        /* Garden variety bubble sort */
+        do {
+                more = 0;
+                q = top;
+                while (q-- > map)
+		{
+                        if (q[1].hash >= q[0].hash)
+				continue;
+                        swap(*(q+1), *q);
+                        more = 1;
+		}
+	} while(more);
+}
+
+static void dx_insert_block(struct dx_frame *frame, u32 hash, u32 block)
+{
+	struct dx_entry *entries = frame->entries;
+	struct dx_entry *old = frame->at, *new = old + 1;
+	int count = dx_get_count(entries);
+
+	assert(count < dx_get_limit(entries));
+	assert(old < entries + count);
+	memmove(new + 1, new, (char *)(entries + count) - (char *)(new));
+	dx_set_hash(new, hash);
+	dx_set_block(new, block);
+	dx_set_count(entries, count + 1);
+}
+#endif
+
+
+static void ext3_update_dx_flag(struct inode *inode)
+{
+	if (!EXT3_HAS_COMPAT_FEATURE(inode->i_sb,
+				     EXT3_FEATURE_COMPAT_DIR_INDEX))
+		EXT3_I(inode)->i_flags &= ~EXT3_INDEX_FL;
+}
+
+/*
+ * NOTE! unlike strncmp, ext3_match returns 1 for success, 0 for failure.
+ *
+ * `len <= EXT3_NAME_LEN' is guaranteed by caller.
+ * `de != NULL' is guaranteed by caller.
+ */
+static inline int ext3_match (int len, const char * const name,
+			      struct ext3_dir_entry_2 * de)
+{
+	if (len != de->name_len)
+		return 0;
+	if (!de->inode)
+		return 0;
+	return !memcmp(name, de->name, len);
+}
+
+/*
+ * Returns 0 if not found, -1 on failure, and 1 on success
+ */
+static inline int search_dirblock(struct buffer_head * bh,
+				  struct inode *dir,
+				  struct dentry *dentry,
+				  unsigned long offset,
+				  struct ext3_dir_entry_2 ** res_dir)
+{
+	struct ext3_dir_entry_2 * de;
+	char * dlimit;
+	int de_len;
+	const char *name = dentry->d_name.name;
+	int namelen = dentry->d_name.len;
+
+	de = (struct ext3_dir_entry_2 *) bh->b_data;
+	dlimit = bh->b_data + dir->i_sb->s_blocksize;
+	while ((char *) de < dlimit) {
+		/* this code is executed quadratically often */
+		/* do minimal checking `by hand' */
+
+		if ((char *) de + namelen <= dlimit &&
+		    ext3_match (namelen, name, de)) {
+			/* found a match - just to be sure, do a full check */
+			if (!ext3_check_dir_entry("ext3_find_entry",
+						  dir, de, bh, offset))
+				return -1;
+			*res_dir = de;
+			return 1;
+		}
+		/* prevent looping on a bad block */
+		de_len = le16_to_cpu(de->rec_len);
+		if (de_len <= 0)
+			return -1;
+		offset += de_len;
+		de = (struct ext3_dir_entry_2 *) ((char *) de + de_len);
+	}
+	return 0;
+}
+
+
+/*
+ *	ext3_find_entry()
+ *
+ * finds an entry in the specified directory with the wanted name. It
+ * returns the cache buffer in which the entry was found, and the entry
+ * itself (as a parameter - res_dir). It does NOT read the inode of the
+ * entry - you'll have to do that yourself if you want to.
+ *
+ * The returned buffer_head has ->b_count elevated.  The caller is expected
+ * to brelse() it when appropriate.
+ */
+static struct buffer_head * ext3_find_entry (struct dentry *dentry,
+					struct ext3_dir_entry_2 ** res_dir)
+{
+	struct super_block * sb;
+	struct buffer_head * bh_use[NAMEI_RA_SIZE];
+	struct buffer_head * bh, *ret = NULL;
+	unsigned long start, block, b;
+	int ra_max = 0;		/* Number of bh's in the readahead
+				   buffer, bh_use[] */
+	int ra_ptr = 0;		/* Current index into readahead
+				   buffer */
+	int num = 0;
+	int nblocks, i, err;
+	struct inode *dir = dentry->d_parent->d_inode;
+	int namelen;
+	const u8 *name;
+	unsigned blocksize;
+
+	*res_dir = NULL;
+	sb = dir->i_sb;
+	blocksize = sb->s_blocksize;
+	namelen = dentry->d_name.len;
+	name = dentry->d_name.name;
+	if (namelen > EXT3_NAME_LEN)
+		return NULL;
+#ifdef CONFIG_EXT3_INDEX
+	if (is_dx(dir)) {
+		bh = ext3_dx_find_entry(dentry, res_dir, &err);
+		/*
+		 * On success, or if the error was file not found,
+		 * return.  Otherwise, fall back to doing a search the
+		 * old fashioned way.
+		 */
+		if (bh || (err != ERR_BAD_DX_DIR))
+			return bh;
+		dxtrace(printk("ext3_find_entry: dx failed, falling back\n"));
+	}
+#endif
+	nblocks = dir->i_size >> EXT3_BLOCK_SIZE_BITS(sb);
+	start = EXT3_I(dir)->i_dir_start_lookup;
+	if (start >= nblocks)
+		start = 0;
+	block = start;
+restart:
+	do {
+		/*
+		 * We deal with the read-ahead logic here.
+		 */
+		if (ra_ptr >= ra_max) {
+			/* Refill the readahead buffer */
+			ra_ptr = 0;
+			b = block;
+			for (ra_max = 0; ra_max < NAMEI_RA_SIZE; ra_max++) {
+				/*
+				 * Terminate if we reach the end of the
+				 * directory and must wrap, or if our
+				 * search has finished at this block.
+				 */
+				if (b >= nblocks || (num && block == start)) {
+					bh_use[ra_max] = NULL;
+					break;
+				}
+				num++;
+				bh = ext3_getblk(NULL, dir, b++, 0, &err);
+				bh_use[ra_max] = bh;
+				if (bh)
+					ll_rw_block(READ_META, 1, &bh);
+			}
+		}
+		if ((bh = bh_use[ra_ptr++]) == NULL)
+			goto next;
+		wait_on_buffer(bh);
+		if (!buffer_uptodate(bh)) {
+			/* read error, skip block & hope for the best */
+			ext3_error(sb, __FUNCTION__, "reading directory #%lu "
+				   "offset %lu", dir->i_ino, block);
+			brelse(bh);
+			goto next;
+		}
+		i = search_dirblock(bh, dir, dentry,
+			    block << EXT3_BLOCK_SIZE_BITS(sb), res_dir);
+		if (i == 1) {
+			EXT3_I(dir)->i_dir_start_lookup = block;
+			ret = bh;
+			goto cleanup_and_exit;
+		} else {
+			brelse(bh);
+			if (i < 0)
+				goto cleanup_and_exit;
+		}
+	next:
+		if (++block >= nblocks)
+			block = 0;
+	} while (block != start);
+
+	/*
+	 * If the directory has grown while we were searching, then
+	 * search the last part of the directory before giving up.
+	 */
+	block = nblocks;
+	nblocks = dir->i_size >> EXT3_BLOCK_SIZE_BITS(sb);
+	if (block < nblocks) {
+		start = 0;
+		goto restart;
+	}
+
+cleanup_and_exit:
+	/* Clean up the read-ahead blocks */
+	for (; ra_ptr < ra_max; ra_ptr++)
+		brelse (bh_use[ra_ptr]);
+	return ret;
+}
+
+#ifdef CONFIG_EXT3_INDEX
+static struct buffer_head * ext3_dx_find_entry(struct dentry *dentry,
+		       struct ext3_dir_entry_2 **res_dir, int *err)
+{
+	struct super_block * sb;
+	struct dx_hash_info	hinfo;
+	u32 hash;
+	struct dx_frame frames[2], *frame;
+	struct ext3_dir_entry_2 *de, *top;
+	struct buffer_head *bh;
+	unsigned long block;
+	int retval;
+	int namelen = dentry->d_name.len;
+	const u8 *name = dentry->d_name.name;
+	struct inode *dir = dentry->d_parent->d_inode;
+
+	sb = dir->i_sb;
+	/* NFS may look up ".." - look at dx_root directory block */
+	if (namelen > 2 || name[0] != '.'||(name[1] != '.' && name[1] != '\0')){
+		if (!(frame = dx_probe(dentry, NULL, &hinfo, frames, err)))
+			return NULL;
+	} else {
+		frame = frames;
+		frame->bh = NULL;			/* for dx_release() */
+		frame->at = (struct dx_entry *)frames;	/* hack for zero entry*/
+		dx_set_block(frame->at, 0);		/* dx_root block is 0 */
+	}
+	hash = hinfo.hash;
+	do {
+		block = dx_get_block(frame->at);
+		if (!(bh = ext3_bread (NULL,dir, block, 0, err)))
+			goto errout;
+		de = (struct ext3_dir_entry_2 *) bh->b_data;
+		top = (struct ext3_dir_entry_2 *) ((char *) de + sb->s_blocksize -
+				       EXT3_DIR_REC_LEN(0));
+		for (; de < top; de = ext3_next_entry(de))
+		if (ext3_match (namelen, name, de)) {
+			if (!ext3_check_dir_entry("ext3_find_entry",
+						  dir, de, bh,
+				  (block<<EXT3_BLOCK_SIZE_BITS(sb))
+					  +((char *)de - bh->b_data))) {
+				brelse (bh);
+				goto errout;
+			}
+			*res_dir = de;
+			dx_release (frames);
+			return bh;
+		}
+		brelse (bh);
+		/* Check to see if we should continue to search */
+		retval = ext3_htree_next_block(dir, hash, frame,
+					       frames, NULL);
+		if (retval < 0) {
+			ext3_warning(sb, __FUNCTION__,
+			     "error reading index page in directory #%lu",
+			     dir->i_ino);
+			*err = retval;
+			goto errout;
+		}
+	} while (retval == 1);
+
+	*err = -ENOENT;
+errout:
+	dxtrace(printk("%s not found\n", name));
+	dx_release (frames);
+	return NULL;
+}
+#endif
+
+static struct dentry *ext3_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd)
+{
+	struct inode * inode;
+	struct ext3_dir_entry_2 * de;
+	struct buffer_head * bh;
+
+	if (dentry->d_name.len > EXT3_NAME_LEN)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	bh = ext3_find_entry(dentry, &de);
+	inode = NULL;
+	if (bh) {
+		unsigned long ino = le32_to_cpu(de->inode);
+		brelse (bh);
+		if (!ext3_valid_inum(dir->i_sb, ino)) {
+			ext3_error(dir->i_sb, "ext3_lookup",
+				   "bad inode number: %lu", ino);
+			inode = NULL;
+		} else
+			inode = iget(dir->i_sb, ino);
+
+		if (!inode)
+			return ERR_PTR(-EACCES);
+	}
+	return d_splice_alias(inode, dentry);
+}
+
+
+struct dentry *ext3_get_parent(struct dentry *child)
+{
+	unsigned long ino;
+	struct dentry *parent;
+	struct inode *inode;
+	struct dentry dotdot;
+	struct ext3_dir_entry_2 * de;
+	struct buffer_head *bh;
+
+	dotdot.d_name.name = "..";
+	dotdot.d_name.len = 2;
+	dotdot.d_parent = child; /* confusing, isn't it! */
+
+	bh = ext3_find_entry(&dotdot, &de);
+	inode = NULL;
+	if (!bh)
+		return ERR_PTR(-ENOENT);
+	ino = le32_to_cpu(de->inode);
+	brelse(bh);
+
+	if (!ext3_valid_inum(child->d_inode->i_sb, ino)) {
+		ext3_error(child->d_inode->i_sb, "ext3_get_parent",
+			   "bad inode number: %lu", ino);
+		inode = NULL;
+	} else
+		inode = iget(child->d_inode->i_sb, ino);
+
+	if (!inode)
+		return ERR_PTR(-EACCES);
+
+	parent = d_alloc_anon(inode);
+	if (!parent) {
+		iput(inode);
+		parent = ERR_PTR(-ENOMEM);
+	}
+	return parent;
+}
+
+#define S_SHIFT 12
+static unsigned char ext3_type_by_mode[S_IFMT >> S_SHIFT] = {
+	[S_IFREG >> S_SHIFT]	= EXT3_FT_REG_FILE,
+	[S_IFDIR >> S_SHIFT]	= EXT3_FT_DIR,
+	[S_IFCHR >> S_SHIFT]	= EXT3_FT_CHRDEV,
+	[S_IFBLK >> S_SHIFT]	= EXT3_FT_BLKDEV,
+	[S_IFIFO >> S_SHIFT]	= EXT3_FT_FIFO,
+	[S_IFSOCK >> S_SHIFT]	= EXT3_FT_SOCK,
+	[S_IFLNK >> S_SHIFT]	= EXT3_FT_SYMLINK,
+};
+
+static inline void ext3_set_de_type(struct super_block *sb,
+				struct ext3_dir_entry_2 *de,
+				umode_t mode) {
+	if (EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_FILETYPE))
+		de->file_type = ext3_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
+}
+
+#ifdef CONFIG_EXT3_INDEX
+static struct ext3_dir_entry_2 *
+dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count)
+{
+	unsigned rec_len = 0;
+
+	while (count--) {
+		struct ext3_dir_entry_2 *de = (struct ext3_dir_entry_2 *) (from + map->offs);
+		rec_len = EXT3_DIR_REC_LEN(de->name_len);
+		memcpy (to, de, rec_len);
+		((struct ext3_dir_entry_2 *) to)->rec_len =
+				cpu_to_le16(rec_len);
+		de->inode = 0;
+		map++;
+		to += rec_len;
+	}
+	return (struct ext3_dir_entry_2 *) (to - rec_len);
+}
+
+static struct ext3_dir_entry_2* dx_pack_dirents(char *base, int size)
+{
+	struct ext3_dir_entry_2 *next, *to, *prev, *de = (struct ext3_dir_entry_2 *) base;
+	unsigned rec_len = 0;
+
+	prev = to = de;
+	while ((char*)de < base + size) {
+		next = (struct ext3_dir_entry_2 *) ((char *) de +
+						    le16_to_cpu(de->rec_len));
+		if (de->inode && de->name_len) {
+			rec_len = EXT3_DIR_REC_LEN(de->name_len);
+			if (de > to)
+				memmove(to, de, rec_len);
+			to->rec_len = cpu_to_le16(rec_len);
+			prev = to;
+			to = (struct ext3_dir_entry_2 *) (((char *) to) + rec_len);
+		}
+		de = next;
+	}
+	return prev;
+}
+
+static struct ext3_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
+			struct buffer_head **bh,struct dx_frame *frame,
+			struct dx_hash_info *hinfo, int *error)
+{
+	unsigned blocksize = dir->i_sb->s_blocksize;
+	unsigned count, continued;
+	struct buffer_head *bh2;
+	u32 newblock;
+	u32 hash2;
+	struct dx_map_entry *map;
+	char *data1 = (*bh)->b_data, *data2;
+	unsigned split;
+	struct ext3_dir_entry_2 *de = NULL, *de2;
+	int	err;
+
+	bh2 = ext3_append (handle, dir, &newblock, error);
+	if (!(bh2)) {
+		brelse(*bh);
+		*bh = NULL;
+		goto errout;
+	}
+
+	BUFFER_TRACE(*bh, "get_write_access");
+	err = ext3_journal_get_write_access(handle, *bh);
+	if (err) {
+	journal_error:
+		brelse(*bh);
+		brelse(bh2);
+		*bh = NULL;
+		ext3_std_error(dir->i_sb, err);
+		goto errout;
+	}
+	BUFFER_TRACE(frame->bh, "get_write_access");
+	err = ext3_journal_get_write_access(handle, frame->bh);
+	if (err)
+		goto journal_error;
+
+	data2 = bh2->b_data;
+
+	/* create map in the end of data2 block */
+	map = (struct dx_map_entry *) (data2 + blocksize);
+	count = dx_make_map ((struct ext3_dir_entry_2 *) data1,
+			     blocksize, hinfo, map);
+	map -= count;
+	split = count/2; // need to adjust to actual middle
+	dx_sort_map (map, count);
+	hash2 = map[split].hash;
+	continued = hash2 == map[split - 1].hash;
+	dxtrace(printk("Split block %i at %x, %i/%i\n",
+		dx_get_block(frame->at), hash2, split, count-split));
+
+	/* Fancy dance to stay within two buffers */
+	de2 = dx_move_dirents(data1, data2, map + split, count - split);
+	de = dx_pack_dirents(data1,blocksize);
+	de->rec_len = cpu_to_le16(data1 + blocksize - (char *) de);
+	de2->rec_len = cpu_to_le16(data2 + blocksize - (char *) de2);
+	dxtrace(dx_show_leaf (hinfo, (struct ext3_dir_entry_2 *) data1, blocksize, 1));
+	dxtrace(dx_show_leaf (hinfo, (struct ext3_dir_entry_2 *) data2, blocksize, 1));
+
+	/* Which block gets the new entry? */
+	if (hinfo->hash >= hash2)
+	{
+		swap(*bh, bh2);
+		de = de2;
+	}
+	dx_insert_block (frame, hash2 + continued, newblock);
+	err = ext3_journal_dirty_metadata (handle, bh2);
+	if (err)
+		goto journal_error;
+	err = ext3_journal_dirty_metadata (handle, frame->bh);
+	if (err)
+		goto journal_error;
+	brelse (bh2);
+	dxtrace(dx_show_index ("frame", frame->entries));
+errout:
+	return de;
+}
+#endif
+
+
+/*
+ * Add a new entry into a directory (leaf) block.  If de is non-NULL,
+ * it points to a directory entry which is guaranteed to be large
+ * enough for new directory entry.  If de is NULL, then
+ * add_dirent_to_buf will attempt search the directory block for
+ * space.  It will return -ENOSPC if no space is available, and -EIO
+ * and -EEXIST if directory entry already exists.
+ *
+ * NOTE!  bh is NOT released in the case where ENOSPC is returned.  In
+ * all other cases bh is released.
+ */
+static int add_dirent_to_buf(handle_t *handle, struct dentry *dentry,
+			     struct inode *inode, struct ext3_dir_entry_2 *de,
+			     struct buffer_head * bh)
+{
+	struct inode	*dir = dentry->d_parent->d_inode;
+	const char	*name = dentry->d_name.name;
+	int		namelen = dentry->d_name.len;
+	unsigned long	offset = 0;
+	unsigned short	reclen;
+	int		nlen, rlen, err;
+	char		*top;
+
+	reclen = EXT3_DIR_REC_LEN(namelen);
+	if (!de) {
+		de = (struct ext3_dir_entry_2 *)bh->b_data;
+		top = bh->b_data + dir->i_sb->s_blocksize - reclen;
+		while ((char *) de <= top) {
+			if (!ext3_check_dir_entry("ext3_add_entry", dir, de,
+						  bh, offset)) {
+				brelse (bh);
+				return -EIO;
+			}
+			if (ext3_match (namelen, name, de)) {
+				brelse (bh);
+				return -EEXIST;
+			}
+			nlen = EXT3_DIR_REC_LEN(de->name_len);
+			rlen = le16_to_cpu(de->rec_len);
+			if ((de->inode? rlen - nlen: rlen) >= reclen)
+				break;
+			de = (struct ext3_dir_entry_2 *)((char *)de + rlen);
+			offset += rlen;
+		}
+		if ((char *) de > top)
+			return -ENOSPC;
+	}
+	BUFFER_TRACE(bh, "get_write_access");
+	err = ext3_journal_get_write_access(handle, bh);
+	if (err) {
+		ext3_std_error(dir->i_sb, err);
+		brelse(bh);
+		return err;
+	}
+
+	/* By now the buffer is marked for journaling */
+	nlen = EXT3_DIR_REC_LEN(de->name_len);
+	rlen = le16_to_cpu(de->rec_len);
+	if (de->inode) {
+		struct ext3_dir_entry_2 *de1 = (struct ext3_dir_entry_2 *)((char *)de + nlen);
+		de1->rec_len = cpu_to_le16(rlen - nlen);
+		de->rec_len = cpu_to_le16(nlen);
+		de = de1;
+	}
+	de->file_type = EXT3_FT_UNKNOWN;
+	if (inode) {
+		de->inode = cpu_to_le32(inode->i_ino);
+		ext3_set_de_type(dir->i_sb, de, inode->i_mode);
+	} else
+		de->inode = 0;
+	de->name_len = namelen;
+	memcpy (de->name, name, namelen);
+	/*
+	 * XXX shouldn't update any times until successful
+	 * completion of syscall, but too many callers depend
+	 * on this.
+	 *
+	 * XXX similarly, too many callers depend on
+	 * ext3_new_inode() setting the times, but error
+	 * recovery deletes the inode, so the worst that can
+	 * happen is that the times are slightly out of date
+	 * and/or different from the directory change time.
+	 */
+	dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
+	ext3_update_dx_flag(dir);
+	dir->i_version++;
+	ext3_mark_inode_dirty(handle, dir);
+	BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
+	err = ext3_journal_dirty_metadata(handle, bh);
+	if (err)
+		ext3_std_error(dir->i_sb, err);
+	brelse(bh);
+	return 0;
+}
+
+#ifdef CONFIG_EXT3_INDEX
+/*
+ * This converts a one block unindexed directory to a 3 block indexed
+ * directory, and adds the dentry to the indexed directory.
+ */
+static int make_indexed_dir(handle_t *handle, struct dentry *dentry,
+			    struct inode *inode, struct buffer_head *bh)
+{
+	struct inode	*dir = dentry->d_parent->d_inode;
+	const char	*name = dentry->d_name.name;
+	int		namelen = dentry->d_name.len;
+	struct buffer_head *bh2;
+	struct dx_root	*root;
+	struct dx_frame	frames[2], *frame;
+	struct dx_entry *entries;
+	struct ext3_dir_entry_2	*de, *de2;
+	char		*data1, *top;
+	unsigned	len;
+	int		retval;
+	unsigned	blocksize;
+	struct dx_hash_info hinfo;
+	u32		block;
+	struct fake_dirent *fde;
+
+	blocksize =  dir->i_sb->s_blocksize;
+	dxtrace(printk("Creating index\n"));
+	retval = ext3_journal_get_write_access(handle, bh);
+	if (retval) {
+		ext3_std_error(dir->i_sb, retval);
+		brelse(bh);
+		return retval;
+	}
+	root = (struct dx_root *) bh->b_data;
+
+	bh2 = ext3_append (handle, dir, &block, &retval);
+	if (!(bh2)) {
+		brelse(bh);
+		return retval;
+	}
+	EXT3_I(dir)->i_flags |= EXT3_INDEX_FL;
+	data1 = bh2->b_data;
+
+	/* The 0th block becomes the root, move the dirents out */
+	fde = &root->dotdot;
+	de = (struct ext3_dir_entry_2 *)((char *)fde + le16_to_cpu(fde->rec_len));
+	len = ((char *) root) + blocksize - (char *) de;
+	memcpy (data1, de, len);
+	de = (struct ext3_dir_entry_2 *) data1;
+	top = data1 + len;
+	while ((char *)(de2=(void*)de+le16_to_cpu(de->rec_len)) < top)
+		de = de2;
+	de->rec_len = cpu_to_le16(data1 + blocksize - (char *) de);
+	/* Initialize the root; the dot dirents already exist */
+	de = (struct ext3_dir_entry_2 *) (&root->dotdot);
+	de->rec_len = cpu_to_le16(blocksize - EXT3_DIR_REC_LEN(2));
+	memset (&root->info, 0, sizeof(root->info));
+	root->info.info_length = sizeof(root->info);
+	root->info.hash_version = EXT3_SB(dir->i_sb)->s_def_hash_version;
+	entries = root->entries;
+	dx_set_block (entries, 1);
+	dx_set_count (entries, 1);
+	dx_set_limit (entries, dx_root_limit(dir, sizeof(root->info)));
+
+	/* Initialize as for dx_probe */
+	hinfo.hash_version = root->info.hash_version;
+	hinfo.seed = EXT3_SB(dir->i_sb)->s_hash_seed;
+	ext3fs_dirhash(name, namelen, &hinfo);
+	frame = frames;
+	frame->entries = entries;
+	frame->at = entries;
+	frame->bh = bh;
+	bh = bh2;
+	de = do_split(handle,dir, &bh, frame, &hinfo, &retval);
+	dx_release (frames);
+	if (!(de))
+		return retval;
+
+	return add_dirent_to_buf(handle, dentry, inode, de, bh);
+}
+#endif
+
+/*
+ *	ext3_add_entry()
+ *
+ * adds a file entry to the specified directory, using the same
+ * semantics as ext3_find_entry(). It returns NULL if it failed.
+ *
+ * NOTE!! The inode part of 'de' is left at 0 - which means you
+ * may not sleep between calling this and putting something into
+ * the entry, as someone else might have used it while you slept.
+ */
+static int ext3_add_entry (handle_t *handle, struct dentry *dentry,
+	struct inode *inode)
+{
+	struct inode *dir = dentry->d_parent->d_inode;
+	unsigned long offset;
+	struct buffer_head * bh;
+	struct ext3_dir_entry_2 *de;
+	struct super_block * sb;
+	int	retval;
+#ifdef CONFIG_EXT3_INDEX
+	int	dx_fallback=0;
+#endif
+	unsigned blocksize;
+	u32 block, blocks;
+
+	sb = dir->i_sb;
+	blocksize = sb->s_blocksize;
+	if (!dentry->d_name.len)
+		return -EINVAL;
+#ifdef CONFIG_EXT3_INDEX
+	if (is_dx(dir)) {
+		retval = ext3_dx_add_entry(handle, dentry, inode);
+		if (!retval || (retval != ERR_BAD_DX_DIR))
+			return retval;
+		EXT3_I(dir)->i_flags &= ~EXT3_INDEX_FL;
+		dx_fallback++;
+		ext3_mark_inode_dirty(handle, dir);
+	}
+#endif
+	blocks = dir->i_size >> sb->s_blocksize_bits;
+	for (block = 0, offset = 0; block < blocks; block++) {
+		bh = ext3_bread(handle, dir, block, 0, &retval);
+		if(!bh)
+			return retval;
+		retval = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
+		if (retval != -ENOSPC)
+			return retval;
+
+#ifdef CONFIG_EXT3_INDEX
+		if (blocks == 1 && !dx_fallback &&
+		    EXT3_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_DIR_INDEX))
+			return make_indexed_dir(handle, dentry, inode, bh);
+#endif
+		brelse(bh);
+	}
+	bh = ext3_append(handle, dir, &block, &retval);
+	if (!bh)
+		return retval;
+	de = (struct ext3_dir_entry_2 *) bh->b_data;
+	de->inode = 0;
+	de->rec_len = cpu_to_le16(blocksize);
+	return add_dirent_to_buf(handle, dentry, inode, de, bh);
+}
+
+#ifdef CONFIG_EXT3_INDEX
+/*
+ * Returns 0 for success, or a negative error value
+ */
+static int ext3_dx_add_entry(handle_t *handle, struct dentry *dentry,
+			     struct inode *inode)
+{
+	struct dx_frame frames[2], *frame;
+	struct dx_entry *entries, *at;
+	struct dx_hash_info hinfo;
+	struct buffer_head * bh;
+	struct inode *dir = dentry->d_parent->d_inode;
+	struct super_block * sb = dir->i_sb;
+	struct ext3_dir_entry_2 *de;
+	int err;
+
+	frame = dx_probe(dentry, NULL, &hinfo, frames, &err);
+	if (!frame)
+		return err;
+	entries = frame->entries;
+	at = frame->at;
+
+	if (!(bh = ext3_bread(handle,dir, dx_get_block(frame->at), 0, &err)))
+		goto cleanup;
+
+	BUFFER_TRACE(bh, "get_write_access");
+	err = ext3_journal_get_write_access(handle, bh);
+	if (err)
+		goto journal_error;
+
+	err = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
+	if (err != -ENOSPC) {
+		bh = NULL;
+		goto cleanup;
+	}
+
+	/* Block full, should compress but for now just split */
+	dxtrace(printk("using %u of %u node entries\n",
+		       dx_get_count(entries), dx_get_limit(entries)));
+	/* Need to split index? */
+	if (dx_get_count(entries) == dx_get_limit(entries)) {
+		u32 newblock;
+		unsigned icount = dx_get_count(entries);
+		int levels = frame - frames;
+		struct dx_entry *entries2;
+		struct dx_node *node2;
+		struct buffer_head *bh2;
+
+		if (levels && (dx_get_count(frames->entries) ==
+			       dx_get_limit(frames->entries))) {
+			ext3_warning(sb, __FUNCTION__,
+				     "Directory index full!");
+			err = -ENOSPC;
+			goto cleanup;
+		}
+		bh2 = ext3_append (handle, dir, &newblock, &err);
+		if (!(bh2))
+			goto cleanup;
+		node2 = (struct dx_node *)(bh2->b_data);
+		entries2 = node2->entries;
+		node2->fake.rec_len = cpu_to_le16(sb->s_blocksize);
+		node2->fake.inode = 0;
+		BUFFER_TRACE(frame->bh, "get_write_access");
+		err = ext3_journal_get_write_access(handle, frame->bh);
+		if (err)
+			goto journal_error;
+		if (levels) {
+			unsigned icount1 = icount/2, icount2 = icount - icount1;
+			unsigned hash2 = dx_get_hash(entries + icount1);
+			dxtrace(printk("Split index %i/%i\n", icount1, icount2));
+
+			BUFFER_TRACE(frame->bh, "get_write_access"); /* index root */
+			err = ext3_journal_get_write_access(handle,
+							     frames[0].bh);
+			if (err)
+				goto journal_error;
+
+			memcpy ((char *) entries2, (char *) (entries + icount1),
+				icount2 * sizeof(struct dx_entry));
+			dx_set_count (entries, icount1);
+			dx_set_count (entries2, icount2);
+			dx_set_limit (entries2, dx_node_limit(dir));
+
+			/* Which index block gets the new entry? */
+			if (at - entries >= icount1) {
+				frame->at = at = at - entries - icount1 + entries2;
+				frame->entries = entries = entries2;
+				swap(frame->bh, bh2);
+			}
+			dx_insert_block (frames + 0, hash2, newblock);
+			dxtrace(dx_show_index ("node", frames[1].entries));
+			dxtrace(dx_show_index ("node",
+			       ((struct dx_node *) bh2->b_data)->entries));
+			err = ext3_journal_dirty_metadata(handle, bh2);
+			if (err)
+				goto journal_error;
+			brelse (bh2);
+		} else {
+			dxtrace(printk("Creating second level index...\n"));
+			memcpy((char *) entries2, (char *) entries,
+			       icount * sizeof(struct dx_entry));
+			dx_set_limit(entries2, dx_node_limit(dir));
+
+			/* Set up root */
+			dx_set_count(entries, 1);
+			dx_set_block(entries + 0, newblock);
+			((struct dx_root *) frames[0].bh->b_data)->info.indirect_levels = 1;
+
+			/* Add new access path frame */
+			frame = frames + 1;
+			frame->at = at = at - entries + entries2;
+			frame->entries = entries = entries2;
+			frame->bh = bh2;
+			err = ext3_journal_get_write_access(handle,
+							     frame->bh);
+			if (err)
+				goto journal_error;
+		}
+		ext3_journal_dirty_metadata(handle, frames[0].bh);
+	}
+	de = do_split(handle, dir, &bh, frame, &hinfo, &err);
+	if (!de)
+		goto cleanup;
+	err = add_dirent_to_buf(handle, dentry, inode, de, bh);
+	bh = NULL;
+	goto cleanup;
+
+journal_error:
+	ext3_std_error(dir->i_sb, err);
+cleanup:
+	if (bh)
+		brelse(bh);
+	dx_release(frames);
+	return err;
+}
+#endif
+
+/*
+ * ext3_delete_entry deletes a directory entry by merging it with the
+ * previous entry
+ */
+static int ext3_delete_entry (handle_t *handle,
+			      struct inode * dir,
+			      struct ext3_dir_entry_2 * de_del,
+			      struct buffer_head * bh)
+{
+	struct ext3_dir_entry_2 * de, * pde;
+	int i;
+
+	i = 0;
+	pde = NULL;
+	de = (struct ext3_dir_entry_2 *) bh->b_data;
+	while (i < bh->b_size) {
+		if (!ext3_check_dir_entry("ext3_delete_entry", dir, de, bh, i))
+			return -EIO;
+		if (de == de_del)  {
+			BUFFER_TRACE(bh, "get_write_access");
+			ext3_journal_get_write_access(handle, bh);
+			if (pde)
+				pde->rec_len =
+					cpu_to_le16(le16_to_cpu(pde->rec_len) +
+						    le16_to_cpu(de->rec_len));
+			else
+				de->inode = 0;
+			dir->i_version++;
+			BUFFER_TRACE(bh, "call ext3_journal_dirty_metadata");
+			ext3_journal_dirty_metadata(handle, bh);
+			return 0;
+		}
+		i += le16_to_cpu(de->rec_len);
+		pde = de;
+		de = (struct ext3_dir_entry_2 *)
+			((char *) de + le16_to_cpu(de->rec_len));
+	}
+	return -ENOENT;
+}
+
+/*
+ * ext3_mark_inode_dirty is somewhat expensive, so unlike ext2 we
+ * do not perform it in these functions.  We perform it at the call site,
+ * if it is needed.
+ */
+static inline void ext3_inc_count(handle_t *handle, struct inode *inode)
+{
+	inc_nlink(inode);
+}
+
+static inline void ext3_dec_count(handle_t *handle, struct inode *inode)
+{
+	drop_nlink(inode);
+}
+
+static int ext3_add_nondir(handle_t *handle,
+		struct dentry *dentry, struct inode *inode)
+{
+	int err = ext3_add_entry(handle, dentry, inode);
+	if (!err) {
+		ext3_mark_inode_dirty(handle, inode);
+		d_instantiate(dentry, inode);
+		return 0;
+	}
+	ext3_dec_count(handle, inode);
+	iput(inode);
+	return err;
+}
+
+/*
+ * By the time this is called, we already have created
+ * the directory cache entry for the new file, but it
+ * is so far negative - it has no inode.
+ *
+ * If the create succeeds, we fill in the inode information
+ * with d_instantiate().
+ */
+static int ext3_create (struct inode * dir, struct dentry * dentry, int mode,
+		struct nameidata *nd)
+{
+	handle_t *handle;
+	struct inode * inode;
+	int err, retries = 0;
+
+retry:
+	handle = ext3_journal_start(dir, EXT3_DATA_TRANS_BLOCKS(dir->i_sb) +
+					EXT3_INDEX_EXTRA_TRANS_BLOCKS + 3 +
+					2*EXT3_QUOTA_INIT_BLOCKS(dir->i_sb));
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	if (IS_DIRSYNC(dir))
+		handle->h_sync = 1;
+
+	inode = ext3_new_inode (handle, dir, mode);
+	err = PTR_ERR(inode);
+	if (!IS_ERR(inode)) {
+		inode->i_op = &ext3_file_inode_operations;
+		inode->i_fop = &ext3_file_operations;
+		ext3_set_aops(inode);
+		err = ext3_add_nondir(handle, dentry, inode);
+	}
+	ext3_journal_stop(handle);
+	if (err == -ENOSPC && ext3_should_retry_alloc(dir->i_sb, &retries))
+		goto retry;
+	return err;
+}
+
+static int ext3_mknod (struct inode * dir, struct dentry *dentry,
+			int mode, dev_t rdev)
+{
+	handle_t *handle;
+	struct inode *inode;
+	int err, retries = 0;
+
+	if (!new_valid_dev(rdev))
+		return -EINVAL;
+
+retry:
+	handle = ext3_journal_start(dir, EXT3_DATA_TRANS_BLOCKS(dir->i_sb) +
+					EXT3_INDEX_EXTRA_TRANS_BLOCKS + 3 +
+					2*EXT3_QUOTA_INIT_BLOCKS(dir->i_sb));
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	if (IS_DIRSYNC(dir))
+		handle->h_sync = 1;
+
+	inode = ext3_new_inode (handle, dir, mode);
+	err = PTR_ERR(inode);
+	if (!IS_ERR(inode)) {
+		init_special_inode(inode, inode->i_mode, rdev);
+#ifdef CONFIG_EXT3_FS_XATTR
+		inode->i_op = &ext3_special_inode_operations;
+#endif
+		err = ext3_add_nondir(handle, dentry, inode);
+	}
+	ext3_journal_stop(handle);
+	if (err == -ENOSPC && ext3_should_retry_alloc(dir->i_sb, &retries))
+		goto retry;
+	return err;
+}
+
+static int ext3_mkdir(struct inode * dir, struct dentry * dentry, int mode)
+{
+	handle_t *handle;
+	struct inode * inode;
+	struct buffer_head * dir_block;
+	struct ext3_dir_entry_2 * de;
+	int err, retries = 0;
+
+	if (dir->i_nlink >= EXT3_LINK_MAX)
+		return -EMLINK;
+
+retry:
+	handle = ext3_journal_start(dir, EXT3_DATA_TRANS_BLOCKS(dir->i_sb) +
+					EXT3_INDEX_EXTRA_TRANS_BLOCKS + 3 +
+					2*EXT3_QUOTA_INIT_BLOCKS(dir->i_sb));
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	if (IS_DIRSYNC(dir))
+		handle->h_sync = 1;
+
+	inode = ext3_new_inode (handle, dir, S_IFDIR | mode);
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out_stop;
+
+	inode->i_op = &ext3_dir_inode_operations;
+	inode->i_fop = &ext3_dir_operations;
+	inode->i_size = EXT3_I(inode)->i_disksize = inode->i_sb->s_blocksize;
+	dir_block = ext3_bread (handle, inode, 0, 1, &err);
+	if (!dir_block) {
+		drop_nlink(inode); /* is this nlink == 0? */
+		ext3_mark_inode_dirty(handle, inode);
+		iput (inode);
+		goto out_stop;
+	}
+	BUFFER_TRACE(dir_block, "get_write_access");
+	ext3_journal_get_write_access(handle, dir_block);
+	de = (struct ext3_dir_entry_2 *) dir_block->b_data;
+	de->inode = cpu_to_le32(inode->i_ino);
+	de->name_len = 1;
+	de->rec_len = cpu_to_le16(EXT3_DIR_REC_LEN(de->name_len));
+	strcpy (de->name, ".");
+	ext3_set_de_type(dir->i_sb, de, S_IFDIR);
+	de = (struct ext3_dir_entry_2 *)
+			((char *) de + le16_to_cpu(de->rec_len));
+	de->inode = cpu_to_le32(dir->i_ino);
+	de->rec_len = cpu_to_le16(inode->i_sb->s_blocksize-EXT3_DIR_REC_LEN(1));
+	de->name_len = 2;
+	strcpy (de->name, "..");
+	ext3_set_de_type(dir->i_sb, de, S_IFDIR);
+	inode->i_nlink = 2;
+	BUFFER_TRACE(dir_block, "call ext3_journal_dirty_metadata");
+	ext3_journal_dirty_metadata(handle, dir_block);
+	brelse (dir_block);
+	ext3_mark_inode_dirty(handle, inode);
+	err = ext3_add_entry (handle, dentry, inode);
+	if (err) {
+		inode->i_nlink = 0;
+		ext3_mark_inode_dirty(handle, inode);
+		iput (inode);
+		goto out_stop;
+	}
+	inc_nlink(dir);
+	ext3_update_dx_flag(dir);
+	ext3_mark_inode_dirty(handle, dir);
+	d_instantiate(dentry, inode);
+out_stop:
+	ext3_journal_stop(handle);
+	if (err == -ENOSPC && ext3_should_retry_alloc(dir->i_sb, &retries))
+		goto retry;
+	return err;
+}
+
+/*
+ * routine to check that the specified directory is empty (for rmdir)
+ */
+static int empty_dir (struct inode * inode)
+{
+	unsigned long offset;
+	struct buffer_head * bh;
+	struct ext3_dir_entry_2 * de, * de1;
+	struct super_block * sb;
+	int err = 0;
+
+	sb = inode->i_sb;
+	if (inode->i_size < EXT3_DIR_REC_LEN(1) + EXT3_DIR_REC_LEN(2) ||
+	    !(bh = ext3_bread (NULL, inode, 0, 0, &err))) {
+		if (err)
+			ext3_error(inode->i_sb, __FUNCTION__,
+				   "error %d reading directory #%lu offset 0",
+				   err, inode->i_ino);
+		else
+			ext3_warning(inode->i_sb, __FUNCTION__,
+				     "bad directory (dir #%lu) - no data block",
+				     inode->i_ino);
+		return 1;
+	}
+	de = (struct ext3_dir_entry_2 *) bh->b_data;
+	de1 = (struct ext3_dir_entry_2 *)
+			((char *) de + le16_to_cpu(de->rec_len));
+	if (le32_to_cpu(de->inode) != inode->i_ino ||
+			!le32_to_cpu(de1->inode) ||
+			strcmp (".", de->name) ||
+			strcmp ("..", de1->name)) {
+		ext3_warning (inode->i_sb, "empty_dir",
+			      "bad directory (dir #%lu) - no `.' or `..'",
+			      inode->i_ino);
+		brelse (bh);
+		return 1;
+	}
+	offset = le16_to_cpu(de->rec_len) + le16_to_cpu(de1->rec_len);
+	de = (struct ext3_dir_entry_2 *)
+			((char *) de1 + le16_to_cpu(de1->rec_len));
+	while (offset < inode->i_size ) {
+		if (!bh ||
+			(void *) de >= (void *) (bh->b_data+sb->s_blocksize)) {
+			err = 0;
+			brelse (bh);
+			bh = ext3_bread (NULL, inode,
+				offset >> EXT3_BLOCK_SIZE_BITS(sb), 0, &err);
+			if (!bh) {
+				if (err)
+					ext3_error(sb, __FUNCTION__,
+						   "error %d reading directory"
+						   " #%lu offset %lu",
+						   err, inode->i_ino, offset);
+				offset += sb->s_blocksize;
+				continue;
+			}
+			de = (struct ext3_dir_entry_2 *) bh->b_data;
+		}
+		if (!ext3_check_dir_entry("empty_dir", inode, de, bh, offset)) {
+			de = (struct ext3_dir_entry_2 *)(bh->b_data +
+							 sb->s_blocksize);
+			offset = (offset | (sb->s_blocksize - 1)) + 1;
+			continue;
+		}
+		if (le32_to_cpu(de->inode)) {
+			brelse (bh);
+			return 0;
+		}
+		offset += le16_to_cpu(de->rec_len);
+		de = (struct ext3_dir_entry_2 *)
+				((char *) de + le16_to_cpu(de->rec_len));
+	}
+	brelse (bh);
+	return 1;
+}
+
+/* ext3_orphan_add() links an unlinked or truncated inode into a list of
+ * such inodes, starting at the superblock, in case we crash before the
+ * file is closed/deleted, or in case the inode truncate spans multiple
+ * transactions and the last transaction is not recovered after a crash.
+ *
+ * At filesystem recovery time, we walk this list deleting unlinked
+ * inodes and truncating linked inodes in ext3_orphan_cleanup().
+ */
+int ext3_orphan_add(handle_t *handle, struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	struct ext3_iloc iloc;
+	int err = 0, rc;
+
+	lock_super(sb);
+	if (!list_empty(&EXT3_I(inode)->i_orphan))
+		goto out_unlock;
+
+	/* Orphan handling is only valid for files with data blocks
+	 * being truncated, or files being unlinked. */
+
+	/* @@@ FIXME: Observation from aviro:
+	 * I think I can trigger J_ASSERT in ext3_orphan_add().  We block
+	 * here (on lock_super()), so race with ext3_link() which might bump
+	 * ->i_nlink. For, say it, character device. Not a regular file,
+	 * not a directory, not a symlink and ->i_nlink > 0.
+	 */
+	J_ASSERT ((S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
+		S_ISLNK(inode->i_mode)) || inode->i_nlink == 0);
+
+	BUFFER_TRACE(EXT3_SB(sb)->s_sbh, "get_write_access");
+	err = ext3_journal_get_write_access(handle, EXT3_SB(sb)->s_sbh);
+	if (err)
+		goto out_unlock;
+
+	err = ext3_reserve_inode_write(handle, inode, &iloc);
+	if (err)
+		goto out_unlock;
+
+	/* Insert this inode at the head of the on-disk orphan list... */
+	NEXT_ORPHAN(inode) = le32_to_cpu(EXT3_SB(sb)->s_es->s_last_orphan);
+	EXT3_SB(sb)->s_es->s_last_orphan = cpu_to_le32(inode->i_ino);
+	err = ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
+	rc = ext3_mark_iloc_dirty(handle, inode, &iloc);
+	if (!err)
+		err = rc;
+
+	/* Only add to the head of the in-memory list if all the
+	 * previous operations succeeded.  If the orphan_add is going to
+	 * fail (possibly taking the journal offline), we can't risk
+	 * leaving the inode on the orphan list: stray orphan-list
+	 * entries can cause panics at unmount time.
+	 *
+	 * This is safe: on error we're going to ignore the orphan list
+	 * anyway on the next recovery. */
+	if (!err)
+		list_add(&EXT3_I(inode)->i_orphan, &EXT3_SB(sb)->s_orphan);
+
+	jbd_debug(4, "superblock will point to %lu\n", inode->i_ino);
+	jbd_debug(4, "orphan inode %lu will point to %d\n",
+			inode->i_ino, NEXT_ORPHAN(inode));
+out_unlock:
+	unlock_super(sb);
+	ext3_std_error(inode->i_sb, err);
+	return err;
+}
+
+/*
+ * ext3_orphan_del() removes an unlinked or truncated inode from the list
+ * of such inodes stored on disk, because it is finally being cleaned up.
+ */
+int ext3_orphan_del(handle_t *handle, struct inode *inode)
+{
+	struct list_head *prev;
+	struct ext3_inode_info *ei = EXT3_I(inode);
+	struct ext3_sb_info *sbi;
+	unsigned long ino_next;
+	struct ext3_iloc iloc;
+	int err = 0;
+
+	lock_super(inode->i_sb);
+	if (list_empty(&ei->i_orphan)) {
+		unlock_super(inode->i_sb);
+		return 0;
+	}
+
+	ino_next = NEXT_ORPHAN(inode);
+	prev = ei->i_orphan.prev;
+	sbi = EXT3_SB(inode->i_sb);
+
+	jbd_debug(4, "remove inode %lu from orphan list\n", inode->i_ino);
+
+	list_del_init(&ei->i_orphan);
+
+	/* If we're on an error path, we may not have a valid
+	 * transaction handle with which to update the orphan list on
+	 * disk, but we still need to remove the inode from the linked
+	 * list in memory. */
+	if (!handle)
+		goto out;
+
+	err = ext3_reserve_inode_write(handle, inode, &iloc);
+	if (err)
+		goto out_err;
+
+	if (prev == &sbi->s_orphan) {
+		jbd_debug(4, "superblock will point to %lu\n", ino_next);
+		BUFFER_TRACE(sbi->s_sbh, "get_write_access");
+		err = ext3_journal_get_write_access(handle, sbi->s_sbh);
+		if (err)
+			goto out_brelse;
+		sbi->s_es->s_last_orphan = cpu_to_le32(ino_next);
+		err = ext3_journal_dirty_metadata(handle, sbi->s_sbh);
+	} else {
+		struct ext3_iloc iloc2;
+		struct inode *i_prev =
+			&list_entry(prev, struct ext3_inode_info, i_orphan)->vfs_inode;
+
+		jbd_debug(4, "orphan inode %lu will point to %lu\n",
+			  i_prev->i_ino, ino_next);
+		err = ext3_reserve_inode_write(handle, i_prev, &iloc2);
+		if (err)
+			goto out_brelse;
+		NEXT_ORPHAN(i_prev) = ino_next;
+		err = ext3_mark_iloc_dirty(handle, i_prev, &iloc2);
+	}
+	if (err)
+		goto out_brelse;
+	NEXT_ORPHAN(inode) = 0;
+	err = ext3_mark_iloc_dirty(handle, inode, &iloc);
+
+out_err:
+	ext3_std_error(inode->i_sb, err);
+out:
+	unlock_super(inode->i_sb);
+	return err;
+
+out_brelse:
+	brelse(iloc.bh);
+	goto out_err;
+}
+
+static int ext3_rmdir (struct inode * dir, struct dentry *dentry)
+{
+	int retval;
+	struct inode * inode;
+	struct buffer_head * bh;
+	struct ext3_dir_entry_2 * de;
+	handle_t *handle;
+
+	/* Initialize quotas before so that eventual writes go in
+	 * separate transaction */
+	DQUOT_INIT(dentry->d_inode);
+	handle = ext3_journal_start(dir, EXT3_DELETE_TRANS_BLOCKS(dir->i_sb));
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	retval = -ENOENT;
+	bh = ext3_find_entry (dentry, &de);
+	if (!bh)
+		goto end_rmdir;
+
+	if (IS_DIRSYNC(dir))
+		handle->h_sync = 1;
+
+	inode = dentry->d_inode;
+
+	retval = -EIO;
+	if (le32_to_cpu(de->inode) != inode->i_ino)
+		goto end_rmdir;
+
+	retval = -ENOTEMPTY;
+	if (!empty_dir (inode))
+		goto end_rmdir;
+
+	retval = ext3_delete_entry(handle, dir, de, bh);
+	if (retval)
+		goto end_rmdir;
+	if (inode->i_nlink != 2)
+		ext3_warning (inode->i_sb, "ext3_rmdir",
+			      "empty directory has nlink!=2 (%d)",
+			      inode->i_nlink);
+	inode->i_version++;
+	clear_nlink(inode);
+	/* There's no need to set i_disksize: the fact that i_nlink is
+	 * zero will ensure that the right thing happens during any
+	 * recovery. */
+	inode->i_size = 0;
+	ext3_orphan_add(handle, inode);
+	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
+	ext3_mark_inode_dirty(handle, inode);
+	drop_nlink(dir);
+	ext3_update_dx_flag(dir);
+	ext3_mark_inode_dirty(handle, dir);
+
+end_rmdir:
+	ext3_journal_stop(handle);
+	brelse (bh);
+	return retval;
+}
+
+static int ext3_unlink(struct inode * dir, struct dentry *dentry)
+{
+	int retval;
+	struct inode * inode;
+	struct buffer_head * bh;
+	struct ext3_dir_entry_2 * de;
+	handle_t *handle;
+
+	/* Initialize quotas before so that eventual writes go
+	 * in separate transaction */
+	DQUOT_INIT(dentry->d_inode);
+	handle = ext3_journal_start(dir, EXT3_DELETE_TRANS_BLOCKS(dir->i_sb));
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	if (IS_DIRSYNC(dir))
+		handle->h_sync = 1;
+
+	retval = -ENOENT;
+	bh = ext3_find_entry (dentry, &de);
+	if (!bh)
+		goto end_unlink;
+
+	inode = dentry->d_inode;
+
+	retval = -EIO;
+	if (le32_to_cpu(de->inode) != inode->i_ino)
+		goto end_unlink;
+
+	if (!inode->i_nlink) {
+		ext3_warning (inode->i_sb, "ext3_unlink",
+			      "Deleting nonexistent file (%lu), %d",
+			      inode->i_ino, inode->i_nlink);
+		inode->i_nlink = 1;
+	}
+	retval = ext3_delete_entry(handle, dir, de, bh);
+	if (retval)
+		goto end_unlink;
+	dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
+	ext3_update_dx_flag(dir);
+	ext3_mark_inode_dirty(handle, dir);
+	drop_nlink(inode);
+	if (!inode->i_nlink)
+		ext3_orphan_add(handle, inode);
+	inode->i_ctime = dir->i_ctime;
+	ext3_mark_inode_dirty(handle, inode);
+	retval = 0;
+
+end_unlink:
+	ext3_journal_stop(handle);
+	brelse (bh);
+	return retval;
+}
+
+static int ext3_symlink (struct inode * dir,
+		struct dentry *dentry, const char * symname)
+{
+	handle_t *handle;
+	struct inode * inode;
+	int l, err, retries = 0;
+
+	l = strlen(symname)+1;
+	if (l > dir->i_sb->s_blocksize)
+		return -ENAMETOOLONG;
+
+retry:
+	handle = ext3_journal_start(dir, EXT3_DATA_TRANS_BLOCKS(dir->i_sb) +
+					EXT3_INDEX_EXTRA_TRANS_BLOCKS + 5 +
+					2*EXT3_QUOTA_INIT_BLOCKS(dir->i_sb));
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	if (IS_DIRSYNC(dir))
+		handle->h_sync = 1;
+
+	inode = ext3_new_inode (handle, dir, S_IFLNK|S_IRWXUGO);
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out_stop;
+
+	if (l > sizeof (EXT3_I(inode)->i_data)) {
+		inode->i_op = &ext3_symlink_inode_operations;
+		ext3_set_aops(inode);
+		/*
+		 * page_symlink() calls into ext3_prepare/commit_write.
+		 * We have a transaction open.  All is sweetness.  It also sets
+		 * i_size in generic_commit_write().
+		 */
+		err = __page_symlink(inode, symname, l,
+				mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);
+		if (err) {
+			ext3_dec_count(handle, inode);
+			ext3_mark_inode_dirty(handle, inode);
+			iput (inode);
+			goto out_stop;
+		}
+	} else {
+		inode->i_op = &ext3_fast_symlink_inode_operations;
+		memcpy((char*)&EXT3_I(inode)->i_data,symname,l);
+		inode->i_size = l-1;
+	}
+	EXT3_I(inode)->i_disksize = inode->i_size;
+	err = ext3_add_nondir(handle, dentry, inode);
+out_stop:
+	ext3_journal_stop(handle);
+	if (err == -ENOSPC && ext3_should_retry_alloc(dir->i_sb, &retries))
+		goto retry;
+	return err;
+}
+
+static int ext3_link (struct dentry * old_dentry,
+		struct inode * dir, struct dentry *dentry)
+{
+	handle_t *handle;
+	struct inode *inode = old_dentry->d_inode;
+	int err, retries = 0;
+
+	if (inode->i_nlink >= EXT3_LINK_MAX)
+		return -EMLINK;
+
+retry:
+	handle = ext3_journal_start(dir, EXT3_DATA_TRANS_BLOCKS(dir->i_sb) +
+					EXT3_INDEX_EXTRA_TRANS_BLOCKS);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	if (IS_DIRSYNC(dir))
+		handle->h_sync = 1;
+
+	inode->i_ctime = CURRENT_TIME_SEC;
+	ext3_inc_count(handle, inode);
+	atomic_inc(&inode->i_count);
+
+	err = ext3_add_nondir(handle, dentry, inode);
+	ext3_journal_stop(handle);
+	if (err == -ENOSPC && ext3_should_retry_alloc(dir->i_sb, &retries))
+		goto retry;
+	return err;
+}
+
+#define PARENT_INO(buffer) \
+	((struct ext3_dir_entry_2 *) ((char *) buffer + \
+	le16_to_cpu(((struct ext3_dir_entry_2 *) buffer)->rec_len)))->inode
+
+/*
+ * Anybody can rename anything with this: the permission checks are left to the
+ * higher-level routines.
+ */
+static int ext3_rename (struct inode * old_dir, struct dentry *old_dentry,
+			   struct inode * new_dir,struct dentry *new_dentry)
+{
+	handle_t *handle;
+	struct inode * old_inode, * new_inode;
+	struct buffer_head * old_bh, * new_bh, * dir_bh;
+	struct ext3_dir_entry_2 * old_de, * new_de;
+	int retval;
+
+	old_bh = new_bh = dir_bh = NULL;
+
+	/* Initialize quotas before so that eventual writes go
+	 * in separate transaction */
+	if (new_dentry->d_inode)
+		DQUOT_INIT(new_dentry->d_inode);
+	handle = ext3_journal_start(old_dir, 2 *
+					EXT3_DATA_TRANS_BLOCKS(old_dir->i_sb) +
+					EXT3_INDEX_EXTRA_TRANS_BLOCKS + 2);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	if (IS_DIRSYNC(old_dir) || IS_DIRSYNC(new_dir))
+		handle->h_sync = 1;
+
+	old_bh = ext3_find_entry (old_dentry, &old_de);
+	/*
+	 *  Check for inode number is _not_ due to possible IO errors.
+	 *  We might rmdir the source, keep it as pwd of some process
+	 *  and merrily kill the link to whatever was created under the
+	 *  same name. Goodbye sticky bit ;-<
+	 */
+	old_inode = old_dentry->d_inode;
+	retval = -ENOENT;
+	if (!old_bh || le32_to_cpu(old_de->inode) != old_inode->i_ino)
+		goto end_rename;
+
+	new_inode = new_dentry->d_inode;
+	new_bh = ext3_find_entry (new_dentry, &new_de);
+	if (new_bh) {
+		if (!new_inode) {
+			brelse (new_bh);
+			new_bh = NULL;
+		}
+	}
+	if (S_ISDIR(old_inode->i_mode)) {
+		if (new_inode) {
+			retval = -ENOTEMPTY;
+			if (!empty_dir (new_inode))
+				goto end_rename;
+		}
+		retval = -EIO;
+		dir_bh = ext3_bread (handle, old_inode, 0, 0, &retval);
+		if (!dir_bh)
+			goto end_rename;
+		if (le32_to_cpu(PARENT_INO(dir_bh->b_data)) != old_dir->i_ino)
+			goto end_rename;
+		retval = -EMLINK;
+		if (!new_inode && new_dir!=old_dir &&
+				new_dir->i_nlink >= EXT3_LINK_MAX)
+			goto end_rename;
+	}
+	if (!new_bh) {
+		retval = ext3_add_entry (handle, new_dentry, old_inode);
+		if (retval)
+			goto end_rename;
+	} else {
+		BUFFER_TRACE(new_bh, "get write access");
+		ext3_journal_get_write_access(handle, new_bh);
+		new_de->inode = cpu_to_le32(old_inode->i_ino);
+		if (EXT3_HAS_INCOMPAT_FEATURE(new_dir->i_sb,
+					      EXT3_FEATURE_INCOMPAT_FILETYPE))
+			new_de->file_type = old_de->file_type;
+		new_dir->i_version++;
+		BUFFER_TRACE(new_bh, "call ext3_journal_dirty_metadata");
+		ext3_journal_dirty_metadata(handle, new_bh);
+		brelse(new_bh);
+		new_bh = NULL;
+	}
+
+	/*
+	 * Like most other Unix systems, set the ctime for inodes on a
+	 * rename.
+	 */
+	old_inode->i_ctime = CURRENT_TIME_SEC;
+	ext3_mark_inode_dirty(handle, old_inode);
+
+	/*
+	 * ok, that's it
+	 */
+	if (le32_to_cpu(old_de->inode) != old_inode->i_ino ||
+	    old_de->name_len != old_dentry->d_name.len ||
+	    strncmp(old_de->name, old_dentry->d_name.name, old_de->name_len) ||
+	    (retval = ext3_delete_entry(handle, old_dir,
+					old_de, old_bh)) == -ENOENT) {
+		/* old_de could have moved from under us during htree split, so
+		 * make sure that we are deleting the right entry.  We might
+		 * also be pointing to a stale entry in the unused part of
+		 * old_bh so just checking inum and the name isn't enough. */
+		struct buffer_head *old_bh2;
+		struct ext3_dir_entry_2 *old_de2;
+
+		old_bh2 = ext3_find_entry(old_dentry, &old_de2);
+		if (old_bh2) {
+			retval = ext3_delete_entry(handle, old_dir,
+						   old_de2, old_bh2);
+			brelse(old_bh2);
+		}
+	}
+	if (retval) {
+		ext3_warning(old_dir->i_sb, "ext3_rename",
+				"Deleting old file (%lu), %d, error=%d",
+				old_dir->i_ino, old_dir->i_nlink, retval);
+	}
+
+	if (new_inode) {
+		drop_nlink(new_inode);
+		new_inode->i_ctime = CURRENT_TIME_SEC;
+	}
+	old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
+	ext3_update_dx_flag(old_dir);
+	if (dir_bh) {
+		BUFFER_TRACE(dir_bh, "get_write_access");
+		ext3_journal_get_write_access(handle, dir_bh);
+		PARENT_INO(dir_bh->b_data) = cpu_to_le32(new_dir->i_ino);
+		BUFFER_TRACE(dir_bh, "call ext3_journal_dirty_metadata");
+		ext3_journal_dirty_metadata(handle, dir_bh);
+		drop_nlink(old_dir);
+		if (new_inode) {
+			drop_nlink(new_inode);
+		} else {
+			inc_nlink(new_dir);
+			ext3_update_dx_flag(new_dir);
+			ext3_mark_inode_dirty(handle, new_dir);
+		}
+	}
+	ext3_mark_inode_dirty(handle, old_dir);
+	if (new_inode) {
+		ext3_mark_inode_dirty(handle, new_inode);
+		if (!new_inode->i_nlink)
+			ext3_orphan_add(handle, new_inode);
+	}
+	retval = 0;
+
+end_rename:
+	brelse (dir_bh);
+	brelse (old_bh);
+	brelse (new_bh);
+	ext3_journal_stop(handle);
+	return retval;
+}
+
+/*
+ * directories can handle most operations...
+ */
+struct inode_operations ext3_dir_inode_operations = {
+	.create		= ext3_create,
+	.lookup		= ext3_lookup,
+	.link		= ext3_link,
+	.unlink		= ext3_unlink,
+	.symlink	= ext3_symlink,
+	.mkdir		= ext3_mkdir,
+	.rmdir		= ext3_rmdir,
+	.mknod		= ext3_mknod,
+	.rename		= ext3_rename,
+	.setattr	= ext3_setattr,
+#ifdef CONFIG_EXT3_FS_XATTR
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= ext3_listxattr,
+	.removexattr	= generic_removexattr,
+#endif
+	.permission	= ext3_permission,
+};
+
+struct inode_operations ext3_special_inode_operations = {
+	.setattr	= ext3_setattr,
+#ifdef CONFIG_EXT3_FS_XATTR
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= ext3_listxattr,
+	.removexattr	= generic_removexattr,
+#endif
+	.permission	= ext3_permission,
+};

fs/ext4/namei.h

+/*  linux/fs/ext3/namei.h
+ *
+ * Copyright (C) 2005 Simtec Electronics
+ *	Ben Dooks <ben@simtec.co.uk>
+ *
+*/
+
+extern struct dentry *ext3_get_parent(struct dentry *child);

fs/ext4/resize.c

+/*
+ *  linux/fs/ext3/resize.c
+ *
+ * Support for resizing an ext3 filesystem while it is mounted.
+ *
+ * Copyright (C) 2001, 2002 Andreas Dilger <adilger@clusterfs.com>
+ *
+ * This could probably be made into a module, because it is not often in use.
+ */
+
+
+#define EXT3FS_DEBUG
+
+#include <linux/sched.h>
+#include <linux/smp_lock.h>
+#include <linux/ext3_jbd.h>
+
+#include <linux/errno.h>
+#include <linux/slab.h>
+
+
+#define outside(b, first, last)	((b) < (first) || (b) >= (last))
+#define inside(b, first, last)	((b) >= (first) && (b) < (last))
+
+static int verify_group_input(struct super_block *sb,
+			      struct ext3_new_group_data *input)
+{
+	struct ext3_sb_info *sbi = EXT3_SB(sb);
+	struct ext3_super_block *es = sbi->s_es;
+	ext3_fsblk_t start = le32_to_cpu(es->s_blocks_count);
+	ext3_fsblk_t end = start + input->blocks_count;
+	unsigned group = input->group;
+	ext3_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;
+	unsigned overhead = ext3_bg_has_super(sb, group) ?
+		(1 + ext3_bg_num_gdb(sb, group) +
+		 le16_to_cpu(es->s_reserved_gdt_blocks)) : 0;
+	ext3_fsblk_t metaend = start + overhead;
+	struct buffer_head *bh = NULL;
+	ext3_grpblk_t free_blocks_count;
+	int err = -EINVAL;
+
+	input->free_blocks_count = free_blocks_count =
+		input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
+
+	if (test_opt(sb, DEBUG))
+		printk(KERN_DEBUG "EXT3-fs: adding %s group %u: %u blocks "
+		       "(%d free, %u reserved)\n",
+		       ext3_bg_has_super(sb, input->group) ? "normal" :
+		       "no-super", input->group, input->blocks_count,
+		       free_blocks_count, input->reserved_blocks);
+
+	if (group != sbi->s_groups_count)
+		ext3_warning(sb, __FUNCTION__,
+			     "Cannot add at group %u (only %lu groups)",
+			     input->group, sbi->s_groups_count);
+	else if ((start - le32_to_cpu(es->s_first_data_block)) %
+		 EXT3_BLOCKS_PER_GROUP(sb))
+		ext3_warning(sb, __FUNCTION__, "Last group not full");
+	else if (input->reserved_blocks > input->blocks_count / 5)
+		ext3_warning(sb, __FUNCTION__, "Reserved blocks too high (%u)",
+			     input->reserved_blocks);
+	else if (free_blocks_count < 0)
+		ext3_warning(sb, __FUNCTION__, "Bad blocks count %u",
+			     input->blocks_count);
+	else if (!(bh = sb_bread(sb, end - 1)))
+		ext3_warning(sb, __FUNCTION__,
+			     "Cannot read last block ("E3FSBLK")",
+			     end - 1);
+	else if (outside(input->block_bitmap, start, end))
+		ext3_warning(sb, __FUNCTION__,
+			     "Block bitmap not in group (block %u)",
+			     input->block_bitmap);
+	else if (outside(input->inode_bitmap, start, end))
+		ext3_warning(sb, __FUNCTION__,
+			     "Inode bitmap not in group (block %u)",
+			     input->inode_bitmap);
+	else if (outside(input->inode_table, start, end) ||
+	         outside(itend - 1, start, end))
+		ext3_warning(sb, __FUNCTION__,
+			     "Inode table not in group (blocks %u-"E3FSBLK")",
+			     input->inode_table, itend - 1);
+	else if (input->inode_bitmap == input->block_bitmap)
+		ext3_warning(sb, __FUNCTION__,
+			     "Block bitmap same as inode bitmap (%u)",
+			     input->block_bitmap);
+	else if (inside(input->block_bitmap, input->inode_table, itend))
+		ext3_warning(sb, __FUNCTION__,
+			     "Block bitmap (%u) in inode table (%u-"E3FSBLK")",
+			     input->block_bitmap, input->inode_table, itend-1);
+	else if (inside(input->inode_bitmap, input->inode_table, itend))
+		ext3_warning(sb, __FUNCTION__,
+			     "Inode bitmap (%u) in inode table (%u-"E3FSBLK")",
+			     input->inode_bitmap, input->inode_table, itend-1);
+	else if (inside(input->block_bitmap, start, metaend))
+		ext3_warning(sb, __FUNCTION__,
+			     "Block bitmap (%u) in GDT table"
+			     " ("E3FSBLK"-"E3FSBLK")",
+			     input->block_bitmap, start, metaend - 1);
+	else if (inside(input->inode_bitmap, start, metaend))
+		ext3_warning(sb, __FUNCTION__,
+			     "Inode bitmap (%u) in GDT table"
+			     " ("E3FSBLK"-"E3FSBLK")",
+			     input->inode_bitmap, start, metaend - 1);
+	else if (inside(input->inode_table, start, metaend) ||
+	         inside(itend - 1, start, metaend))
+		ext3_warning(sb, __FUNCTION__,
+			     "Inode table (%u-"E3FSBLK") overlaps"
+			     "GDT table ("E3FSBLK"-"E3FSBLK")",
+			     input->inode_table, itend - 1, start, metaend - 1);
+	else
+		err = 0;
+	brelse(bh);
+
+	return err;
+}
+
+static struct buffer_head *bclean(handle_t *handle, struct super_block *sb,
+				  ext3_fsblk_t blk)
+{
+	struct buffer_head *bh;
+	int err;
+
+	bh = sb_getblk(sb, blk);
+	if (!bh)
+		return ERR_PTR(-EIO);
+	if ((err = ext3_journal_get_write_access(handle, bh))) {
+		brelse(bh);
+		bh = ERR_PTR(err);
+	} else {
+		lock_buffer(bh);
+		memset(bh->b_data, 0, sb->s_blocksize);
+		set_buffer_uptodate(bh);
+		unlock_buffer(bh);
+	}
+
+	return bh;
+}
+
+/*
+ * To avoid calling the atomic setbit hundreds or thousands of times, we only
+ * need to use it within a single byte (to ensure we get endianness right).
+ * We can use memset for the rest of the bitmap as there are no other users.
+ */
+static void mark_bitmap_end(int start_bit, int end_bit, char *bitmap)
+{
+	int i;
+
+	if (start_bit >= end_bit)
+		return;
+
+	ext3_debug("mark end bits +%d through +%d used\n", start_bit, end_bit);
+	for (i = start_bit; i < ((start_bit + 7) & ~7UL); i++)
+		ext3_set_bit(i, bitmap);
+	if (i < end_bit)
+		memset(bitmap + (i >> 3), 0xff, (end_bit - i) >> 3);
+}
+
+/*
+ * Set up the block and inode bitmaps, and the inode table for the new group.
+ * This doesn't need to be part of the main transaction, since we are only
+ * changing blocks outside the actual filesystem.  We still do journaling to
+ * ensure the recovery is correct in case of a failure just after resize.
+ * If any part of this fails, we simply abort the resize.
+ */
+static int setup_new_group_blocks(struct super_block *sb,
+				  struct ext3_new_group_data *input)
+{
+	struct ext3_sb_info *sbi = EXT3_SB(sb);
+	ext3_fsblk_t start = ext3_group_first_block_no(sb, input->group);
+	int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
+		le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) : 0;
+	unsigned long gdblocks = ext3_bg_num_gdb(sb, input->group);
+	struct buffer_head *bh;
+	handle_t *handle;
+	ext3_fsblk_t block;
+	ext3_grpblk_t bit;
+	int i;
+	int err = 0, err2;
+
+	handle = ext3_journal_start_sb(sb, reserved_gdb + gdblocks +
+				       2 + sbi->s_itb_per_group);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	lock_super(sb);
+	if (input->group != sbi->s_groups_count) {
+		err = -EBUSY;
+		goto exit_journal;
+	}
+
+	if (IS_ERR(bh = bclean(handle, sb, input->block_bitmap))) {
+		err = PTR_ERR(bh);
+		goto exit_journal;
+	}
+
+	if (ext3_bg_has_super(sb, input->group)) {
+		ext3_debug("mark backup superblock %#04lx (+0)\n", start);
+		ext3_set_bit(0, bh->b_data);
+	}
+
+	/* Copy all of the GDT blocks into the backup in this group */
+	for (i = 0, bit = 1, block = start + 1;
+	     i < gdblocks; i++, block++, bit++) {
+		struct buffer_head *gdb;
+
+		ext3_debug("update backup group %#04lx (+%d)\n", block, bit);
+
+		gdb = sb_getblk(sb, block);
+		if (!gdb) {
+			err = -EIO;
+			goto exit_bh;
+		}
+		if ((err = ext3_journal_get_write_access(handle, gdb))) {
+			brelse(gdb);
+			goto exit_bh;
+		}
+		lock_buffer(bh);
+		memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, bh->b_size);
+		set_buffer_uptodate(gdb);
+		unlock_buffer(bh);
+		ext3_journal_dirty_metadata(handle, gdb);
+		ext3_set_bit(bit, bh->b_data);
+		brelse(gdb);
+	}
+
+	/* Zero out all of the reserved backup group descriptor table blocks */
+	for (i = 0, bit = gdblocks + 1, block = start + bit;
+	     i < reserved_gdb; i++, block++, bit++) {
+		struct buffer_head *gdb;
+
+		ext3_debug("clear reserved block %#04lx (+%d)\n", block, bit);
+
+		if (IS_ERR(gdb = bclean(handle, sb, block))) {
+			err = PTR_ERR(bh);
+			goto exit_bh;
+		}
+		ext3_journal_dirty_metadata(handle, gdb);
+		ext3_set_bit(bit, bh->b_data);
+		brelse(gdb);
+	}
+	ext3_debug("mark block bitmap %#04x (+%ld)\n", input->block_bitmap,
+		   input->block_bitmap - start);
+	ext3_set_bit(input->block_bitmap - start, bh->b_data);
+	ext3_debug("mark inode bitmap %#04x (+%ld)\n", input->inode_bitmap,
+		   input->inode_bitmap - start);
+	ext3_set_bit(input->inode_bitmap - start, bh->b_data);
+
+	/* Zero out all of the inode table blocks */
+	for (i = 0, block = input->inode_table, bit = block - start;
+	     i < sbi->s_itb_per_group; i++, bit++, block++) {
+		struct buffer_head *it;
+
+		ext3_debug("clear inode block %#04lx (+%d)\n", block, bit);
+		if (IS_ERR(it = bclean(handle, sb, block))) {
+			err = PTR_ERR(it);
+			goto exit_bh;
+		}
+		ext3_journal_dirty_metadata(handle, it);
+		brelse(it);
+		ext3_set_bit(bit, bh->b_data);
+	}
+	mark_bitmap_end(input->blocks_count, EXT3_BLOCKS_PER_GROUP(sb),
+			bh->b_data);
+	ext3_journal_dirty_metadata(handle, bh);
+	brelse(bh);
+
+	/* Mark unused entries in inode bitmap used */
+	ext3_debug("clear inode bitmap %#04x (+%ld)\n",
+		   input->inode_bitmap, input->inode_bitmap - start);
+	if (IS_ERR(bh = bclean(handle, sb, input->inode_bitmap))) {
+		err = PTR_ERR(bh);
+		goto exit_journal;
+	}
+
+	mark_bitmap_end(EXT3_INODES_PER_GROUP(sb), EXT3_BLOCKS_PER_GROUP(sb),
+			bh->b_data);
+	ext3_journal_dirty_metadata(handle, bh);
+exit_bh:
+	brelse(bh);
+
+exit_journal:
+	unlock_super(sb);
+	if ((err2 = ext3_journal_stop(handle)) && !err)
+		err = err2;
+
+	return err;
+}
+
+/*
+ * Iterate through the groups which hold BACKUP superblock/GDT copies in an
+ * ext3 filesystem.  The counters should be initialized to 1, 5, and 7 before
+ * calling this for the first time.  In a sparse filesystem it will be the
+ * sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
+ * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
+ */
+static unsigned ext3_list_backups(struct super_block *sb, unsigned *three,
+				  unsigned *five, unsigned *seven)
+{
+	unsigned *min = three;
+	int mult = 3;
+	unsigned ret;
+
+	if (!EXT3_HAS_RO_COMPAT_FEATURE(sb,
+					EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
+		ret = *min;
+		*min += 1;
+		return ret;
+	}
+
+	if (*five < *min) {
+		min = five;
+		mult = 5;
+	}
+	if (*seven < *min) {
+		min = seven;
+		mult = 7;
+	}
+
+	ret = *min;
+	*min *= mult;
+
+	return ret;
+}
+
+/*
+ * Check that all of the backup GDT blocks are held in the primary GDT block.
+ * It is assumed that they are stored in group order.  Returns the number of
+ * groups in current filesystem that have BACKUPS, or -ve error code.
+ */
+static int verify_reserved_gdb(struct super_block *sb,
+			       struct buffer_head *primary)
+{
+	const ext3_fsblk_t blk = primary->b_blocknr;
+	const unsigned long end = EXT3_SB(sb)->s_groups_count;
+	unsigned three = 1;
+	unsigned five = 5;
+	unsigned seven = 7;
+	unsigned grp;
+	__le32 *p = (__le32 *)primary->b_data;
+	int gdbackups = 0;
+
+	while ((grp = ext3_list_backups(sb, &three, &five, &seven)) < end) {
+		if (le32_to_cpu(*p++) != grp * EXT3_BLOCKS_PER_GROUP(sb) + blk){
+			ext3_warning(sb, __FUNCTION__,
+				     "reserved GDT "E3FSBLK
+				     " missing grp %d ("E3FSBLK")",
+				     blk, grp,
+				     grp * EXT3_BLOCKS_PER_GROUP(sb) + blk);
+			return -EINVAL;
+		}
+		if (++gdbackups > EXT3_ADDR_PER_BLOCK(sb))
+			return -EFBIG;
+	}
+
+	return gdbackups;
+}
+
+/*
+ * Called when we need to bring a reserved group descriptor table block into
+ * use from the resize inode.  The primary copy of the new GDT block currently
+ * is an indirect block (under the double indirect block in the resize inode).
+ * The new backup GDT blocks will be stored as leaf blocks in this indirect
+ * block, in group order.  Even though we know all the block numbers we need,
+ * we check to ensure that the resize inode has actually reserved these blocks.
+ *
+ * Don't need to update the block bitmaps because the blocks are still in use.
+ *
+ * We get all of the error cases out of the way, so that we are sure to not
+ * fail once we start modifying the data on disk, because JBD has no rollback.
+ */
+static int add_new_gdb(handle_t *handle, struct inode *inode,
+		       struct ext3_new_group_data *input,
+		       struct buffer_head **primary)
+{
+	struct super_block *sb = inode->i_sb;
+	struct ext3_super_block *es = EXT3_SB(sb)->s_es;
+	unsigned long gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
+	ext3_fsblk_t gdblock = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + gdb_num;
+	struct buffer_head **o_group_desc, **n_group_desc;
+	struct buffer_head *dind;
+	int gdbackups;
+	struct ext3_iloc iloc;
+	__le32 *data;
+	int err;
+
+	if (test_opt(sb, DEBUG))
+		printk(KERN_DEBUG
+		       "EXT3-fs: ext3_add_new_gdb: adding group block %lu\n",
+		       gdb_num);
+
+	/*
+	 * If we are not using the primary superblock/GDT copy don't resize,
+	 * because the user tools have no way of handling this.  Probably a
+	 * bad time to do it anyways.
+	 */
+	if (EXT3_SB(sb)->s_sbh->b_blocknr !=
+	    le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block)) {
+		ext3_warning(sb, __FUNCTION__,
+			"won't resize using backup superblock at %llu",
+			(unsigned long long)EXT3_SB(sb)->s_sbh->b_blocknr);
+		return -EPERM;
+	}
+
+	*primary = sb_bread(sb, gdblock);
+	if (!*primary)
+		return -EIO;
+
+	if ((gdbackups = verify_reserved_gdb(sb, *primary)) < 0) {
+		err = gdbackups;
+		goto exit_bh;
+	}
+
+	data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
+	dind = sb_bread(sb, le32_to_cpu(*data));
+	if (!dind) {
+		err = -EIO;
+		goto exit_bh;
+	}
+
+	data = (__le32 *)dind->b_data;
+	if (le32_to_cpu(data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)]) != gdblock) {
+		ext3_warning(sb, __FUNCTION__,
+			     "new group %u GDT block "E3FSBLK" not reserved",
+			     input->group, gdblock);
+		err = -EINVAL;
+		goto exit_dind;
+	}
+
+	if ((err = ext3_journal_get_write_access(handle, EXT3_SB(sb)->s_sbh)))
+		goto exit_dind;
+
+	if ((err = ext3_journal_get_write_access(handle, *primary)))
+		goto exit_sbh;
+
+	if ((err = ext3_journal_get_write_access(handle, dind)))
+		goto exit_primary;
+
+	/* ext3_reserve_inode_write() gets a reference on the iloc */
+	if ((err = ext3_reserve_inode_write(handle, inode, &iloc)))
+		goto exit_dindj;
+
+	n_group_desc = kmalloc((gdb_num + 1) * sizeof(struct buffer_head *),
+			GFP_KERNEL);
+	if (!n_group_desc) {
+		err = -ENOMEM;
+		ext3_warning (sb, __FUNCTION__,
+			      "not enough memory for %lu groups", gdb_num + 1);
+		goto exit_inode;
+	}
+
+	/*
+	 * Finally, we have all of the possible failures behind us...
+	 *
+	 * Remove new GDT block from inode double-indirect block and clear out
+	 * the new GDT block for use (which also "frees" the backup GDT blocks
+	 * from the reserved inode).  We don't need to change the bitmaps for
+	 * these blocks, because they are marked as in-use from being in the
+	 * reserved inode, and will become GDT blocks (primary and backup).
+	 */
+	data[gdb_num % EXT3_ADDR_PER_BLOCK(sb)] = 0;
+	ext3_journal_dirty_metadata(handle, dind);
+	brelse(dind);
+	inode->i_blocks -= (gdbackups + 1) * sb->s_blocksize >> 9;
+	ext3_mark_iloc_dirty(handle, inode, &iloc);
+	memset((*primary)->b_data, 0, sb->s_blocksize);
+	ext3_journal_dirty_metadata(handle, *primary);
+
+	o_group_desc = EXT3_SB(sb)->s_group_desc;
+	memcpy(n_group_desc, o_group_desc,
+	       EXT3_SB(sb)->s_gdb_count * sizeof(struct buffer_head *));
+	n_group_desc[gdb_num] = *primary;
+	EXT3_SB(sb)->s_group_desc = n_group_desc;
+	EXT3_SB(sb)->s_gdb_count++;
+	kfree(o_group_desc);
+
+	es->s_reserved_gdt_blocks =
+		cpu_to_le16(le16_to_cpu(es->s_reserved_gdt_blocks) - 1);
+	ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
+
+	return 0;
+
+exit_inode:
+	//ext3_journal_release_buffer(handle, iloc.bh);
+	brelse(iloc.bh);
+exit_dindj:
+	//ext3_journal_release_buffer(handle, dind);
+exit_primary:
+	//ext3_journal_release_buffer(handle, *primary);
+exit_sbh:
+	//ext3_journal_release_buffer(handle, *primary);
+exit_dind:
+	brelse(dind);
+exit_bh:
+	brelse(*primary);
+
+	ext3_debug("leaving with error %d\n", err);
+	return err;
+}
+
+/*
+ * Called when we are adding a new group which has a backup copy of each of
+ * the GDT blocks (i.e. sparse group) and there are reserved GDT blocks.
+ * We need to add these reserved backup GDT blocks to the resize inode, so
+ * that they are kept for future resizing and not allocated to files.
+ *
+ * Each reserved backup GDT block will go into a different indirect block.
+ * The indirect blocks are actually the primary reserved GDT blocks,
+ * so we know in advance what their block numbers are.  We only get the
+ * double-indirect block to verify it is pointing to the primary reserved
+ * GDT blocks so we don't overwrite a data block by accident.  The reserved
+ * backup GDT blocks are stored in their reserved primary GDT block.
+ */
+static int reserve_backup_gdb(handle_t *handle, struct inode *inode,
+			      struct ext3_new_group_data *input)
+{
+	struct super_block *sb = inode->i_sb;
+	int reserved_gdb =le16_to_cpu(EXT3_SB(sb)->s_es->s_reserved_gdt_blocks);
+	struct buffer_head **primary;
+	struct buffer_head *dind;
+	struct ext3_iloc iloc;
+	ext3_fsblk_t blk;
+	__le32 *data, *end;
+	int gdbackups = 0;
+	int res, i;
+	int err;
+
+	primary = kmalloc(reserved_gdb * sizeof(*primary), GFP_KERNEL);
+	if (!primary)
+		return -ENOMEM;
+
+	data = EXT3_I(inode)->i_data + EXT3_DIND_BLOCK;
+	dind = sb_bread(sb, le32_to_cpu(*data));
+	if (!dind) {
+		err = -EIO;
+		goto exit_free;
+	}
+
+	blk = EXT3_SB(sb)->s_sbh->b_blocknr + 1 + EXT3_SB(sb)->s_gdb_count;
+	data = (__le32 *)dind->b_data + EXT3_SB(sb)->s_gdb_count;
+	end = (__le32 *)dind->b_data + EXT3_ADDR_PER_BLOCK(sb);
+
+	/* Get each reserved primary GDT block and verify it holds backups */
+	for (res = 0; res < reserved_gdb; res++, blk++) {
+		if (le32_to_cpu(*data) != blk) {
+			ext3_warning(sb, __FUNCTION__,
+				     "reserved block "E3FSBLK
+				     " not at offset %ld",
+				     blk,
+				     (long)(data - (__le32 *)dind->b_data));
+			err = -EINVAL;
+			goto exit_bh;
+		}
+		primary[res] = sb_bread(sb, blk);
+		if (!primary[res]) {
+			err = -EIO;
+			goto exit_bh;
+		}
+		if ((gdbackups = verify_reserved_gdb(sb, primary[res])) < 0) {
+			brelse(primary[res]);
+			err = gdbackups;
+			goto exit_bh;
+		}
+		if (++data >= end)
+			data = (__le32 *)dind->b_data;
+	}
+
+	for (i = 0; i < reserved_gdb; i++) {
+		if ((err = ext3_journal_get_write_access(handle, primary[i]))) {
+			/*
+			int j;
+			for (j = 0; j < i; j++)
+				ext3_journal_release_buffer(handle, primary[j]);
+			 */
+			goto exit_bh;
+		}
+	}
+
+	if ((err = ext3_reserve_inode_write(handle, inode, &iloc)))
+		goto exit_bh;
+
+	/*
+	 * Finally we can add each of the reserved backup GDT blocks from
+	 * the new group to its reserved primary GDT block.
+	 */
+	blk = input->group * EXT3_BLOCKS_PER_GROUP(sb);
+	for (i = 0; i < reserved_gdb; i++) {
+		int err2;
+		data = (__le32 *)primary[i]->b_data;
+		/* printk("reserving backup %lu[%u] = %lu\n",
+		       primary[i]->b_blocknr, gdbackups,
+		       blk + primary[i]->b_blocknr); */
+		data[gdbackups] = cpu_to_le32(blk + primary[i]->b_blocknr);
+		err2 = ext3_journal_dirty_metadata(handle, primary[i]);
+		if (!err)
+			err = err2;
+	}
+	inode->i_blocks += reserved_gdb * sb->s_blocksize >> 9;
+	ext3_mark_iloc_dirty(handle, inode, &iloc);
+
+exit_bh:
+	while (--res >= 0)
+		brelse(primary[res]);
+	brelse(dind);
+
+exit_free:
+	kfree(primary);
+
+	return err;
+}
+
+/*
+ * Update the backup copies of the ext3 metadata.  These don't need to be part
+ * of the main resize transaction, because e2fsck will re-write them if there
+ * is a problem (basically only OOM will cause a problem).  However, we
+ * _should_ update the backups if possible, in case the primary gets trashed
+ * for some reason and we need to run e2fsck from a backup superblock.  The
+ * important part is that the new block and inode counts are in the backup
+ * superblocks, and the location of the new group metadata in the GDT backups.
+ *
+ * We do not need lock_super() for this, because these blocks are not
+ * otherwise touched by the filesystem code when it is mounted.  We don't
+ * need to worry about last changing from sbi->s_groups_count, because the
+ * worst that can happen is that we do not copy the full number of backups
+ * at this time.  The resize which changed s_groups_count will backup again.
+ */
+static void update_backups(struct super_block *sb,
+			   int blk_off, char *data, int size)
+{
+	struct ext3_sb_info *sbi = EXT3_SB(sb);
+	const unsigned long last = sbi->s_groups_count;
+	const int bpg = EXT3_BLOCKS_PER_GROUP(sb);
+	unsigned three = 1;
+	unsigned five = 5;
+	unsigned seven = 7;
+	unsigned group;
+	int rest = sb->s_blocksize - size;
+	handle_t *handle;
+	int err = 0, err2;
+
+	handle = ext3_journal_start_sb(sb, EXT3_MAX_TRANS_DATA);
+	if (IS_ERR(handle)) {
+		group = 1;
+		err = PTR_ERR(handle);
+		goto exit_err;
+	}
+
+	while ((group = ext3_list_backups(sb, &three, &five, &seven)) < last) {
+		struct buffer_head *bh;
+
+		/* Out of journal space, and can't get more - abort - so sad */
+		if (handle->h_buffer_credits == 0 &&
+		    ext3_journal_extend(handle, EXT3_MAX_TRANS_DATA) &&
+		    (err = ext3_journal_restart(handle, EXT3_MAX_TRANS_DATA)))
+			break;
+
+		bh = sb_getblk(sb, group * bpg + blk_off);
+		if (!bh) {
+			err = -EIO;
+			break;
+		}
+		ext3_debug("update metadata backup %#04lx\n",
+			  (unsigned long)bh->b_blocknr);
+		if ((err = ext3_journal_get_write_access(handle, bh)))
+			break;
+		lock_buffer(bh);
+		memcpy(bh->b_data, data, size);
+		if (rest)
+			memset(bh->b_data + size, 0, rest);
+		set_buffer_uptodate(bh);
+		unlock_buffer(bh);
+		ext3_journal_dirty_metadata(handle, bh);
+		brelse(bh);
+	}
+	if ((err2 = ext3_journal_stop(handle)) && !err)
+		err = err2;
+
+	/*
+	 * Ugh! Need to have e2fsck write the backup copies.  It is too
+	 * late to revert the resize, we shouldn't fail just because of
+	 * the backup copies (they are only needed in case of corruption).
+	 *
+	 * However, if we got here we have a journal problem too, so we
+	 * can't really start a transaction to mark the superblock.
+	 * Chicken out and just set the flag on the hope it will be written
+	 * to disk, and if not - we will simply wait until next fsck.
+	 */
+exit_err:
+	if (err) {
+		ext3_warning(sb, __FUNCTION__,
+			     "can't update backup for group %d (err %d), "
+			     "forcing fsck on next reboot", group, err);
+		sbi->s_mount_state &= ~EXT3_VALID_FS;
+		sbi->s_es->s_state &= cpu_to_le16(~EXT3_VALID_FS);
+		mark_buffer_dirty(sbi->s_sbh);
+	}
+}
+
+/* Add group descriptor data to an existing or new group descriptor block.
+ * Ensure we handle all possible error conditions _before_ we start modifying
+ * the filesystem, because we cannot abort the transaction and not have it
+ * write the data to disk.
+ *
+ * If we are on a GDT block boundary, we need to get the reserved GDT block.
+ * Otherwise, we may need to add backup GDT blocks for a sparse group.
+ *
+ * We only need to hold the superblock lock while we are actually adding
+ * in the new group's counts to the superblock.  Prior to that we have
+ * not really "added" the group at all.  We re-check that we are still
+ * adding in the last group in case things have changed since verifying.
+ */
+int ext3_group_add(struct super_block *sb, struct ext3_new_group_data *input)
+{
+	struct ext3_sb_info *sbi = EXT3_SB(sb);
+	struct ext3_super_block *es = sbi->s_es;
+	int reserved_gdb = ext3_bg_has_super(sb, input->group) ?
+		le16_to_cpu(es->s_reserved_gdt_blocks) : 0;
+	struct buffer_head *primary = NULL;
+	struct ext3_group_desc *gdp;
+	struct inode *inode = NULL;
+	handle_t *handle;
+	int gdb_off, gdb_num;
+	int err, err2;
+
+	gdb_num = input->group / EXT3_DESC_PER_BLOCK(sb);
+	gdb_off = input->group % EXT3_DESC_PER_BLOCK(sb);
+
+	if (gdb_off == 0 && !EXT3_HAS_RO_COMPAT_FEATURE(sb,
+					EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
+		ext3_warning(sb, __FUNCTION__,
+			     "Can't resize non-sparse filesystem further");
+		return -EPERM;
+	}
+
+	if (le32_to_cpu(es->s_blocks_count) + input->blocks_count <
+	    le32_to_cpu(es->s_blocks_count)) {
+		ext3_warning(sb, __FUNCTION__, "blocks_count overflow\n");
+		return -EINVAL;
+	}
+
+	if (le32_to_cpu(es->s_inodes_count) + EXT3_INODES_PER_GROUP(sb) <
+	    le32_to_cpu(es->s_inodes_count)) {
+		ext3_warning(sb, __FUNCTION__, "inodes_count overflow\n");
+		return -EINVAL;
+	}
+
+	if (reserved_gdb || gdb_off == 0) {
+		if (!EXT3_HAS_COMPAT_FEATURE(sb,
+					     EXT3_FEATURE_COMPAT_RESIZE_INODE)){
+			ext3_warning(sb, __FUNCTION__,
+				     "No reserved GDT blocks, can't resize");
+			return -EPERM;
+		}
+		inode = iget(sb, EXT3_RESIZE_INO);
+		if (!inode || is_bad_inode(inode)) {
+			ext3_warning(sb, __FUNCTION__,
+				     "Error opening resize inode");
+			iput(inode);
+			return -ENOENT;
+		}
+	}
+
+	if ((err = verify_group_input(sb, input)))
+		goto exit_put;
+
+	if ((err = setup_new_group_blocks(sb, input)))
+		goto exit_put;
+
+	/*
+	 * We will always be modifying at least the superblock and a GDT
+	 * block.  If we are adding a group past the last current GDT block,
+	 * we will also modify the inode and the dindirect block.  If we
+	 * are adding a group with superblock/GDT backups  we will also
+	 * modify each of the reserved GDT dindirect blocks.
+	 */
+	handle = ext3_journal_start_sb(sb,
+				       ext3_bg_has_super(sb, input->group) ?
+				       3 + reserved_gdb : 4);
+	if (IS_ERR(handle)) {
+		err = PTR_ERR(handle);
+		goto exit_put;
+	}
+
+	lock_super(sb);
+	if (input->group != sbi->s_groups_count) {
+		ext3_warning(sb, __FUNCTION__,
+			     "multiple resizers run on filesystem!");
+		err = -EBUSY;
+		goto exit_journal;
+	}
+
+	if ((err = ext3_journal_get_write_access(handle, sbi->s_sbh)))
+		goto exit_journal;
+
+	/*
+	 * We will only either add reserved group blocks to a backup group
+	 * or remove reserved blocks for the first group in a new group block.
+	 * Doing both would be mean more complex code, and sane people don't
+	 * use non-sparse filesystems anymore.  This is already checked above.
+	 */
+	if (gdb_off) {
+		primary = sbi->s_group_desc[gdb_num];
+		if ((err = ext3_journal_get_write_access(handle, primary)))
+			goto exit_journal;
+
+		if (reserved_gdb && ext3_bg_num_gdb(sb, input->group) &&
+		    (err = reserve_backup_gdb(handle, inode, input)))
+			goto exit_journal;
+	} else if ((err = add_new_gdb(handle, inode, input, &primary)))
+		goto exit_journal;
+
+	/*
+	 * OK, now we've set up the new group.  Time to make it active.
+	 *
+	 * Current kernels don't lock all allocations via lock_super(),
+	 * so we have to be safe wrt. concurrent accesses the group
+	 * data.  So we need to be careful to set all of the relevant
+	 * group descriptor data etc. *before* we enable the group.
+	 *
+	 * The key field here is sbi->s_groups_count: as long as
+	 * that retains its old value, nobody is going to access the new
+	 * group.
+	 *
+	 * So first we update all the descriptor metadata for the new
+	 * group; then we update the total disk blocks count; then we
+	 * update the groups count to enable the group; then finally we
+	 * update the free space counts so that the system can start
+	 * using the new disk blocks.
+	 */
+
+	/* Update group descriptor block for new group */
+	gdp = (struct ext3_group_desc *)primary->b_data + gdb_off;
+
+	gdp->bg_block_bitmap = cpu_to_le32(input->block_bitmap);
+	gdp->bg_inode_bitmap = cpu_to_le32(input->inode_bitmap);
+	gdp->bg_inode_table = cpu_to_le32(input->inode_table);
+	gdp->bg_free_blocks_count = cpu_to_le16(input->free_blocks_count);
+	gdp->bg_free_inodes_count = cpu_to_le16(EXT3_INODES_PER_GROUP(sb));
+
+	/*
+	 * Make the new blocks and inodes valid next.  We do this before
+	 * increasing the group count so that once the group is enabled,
+	 * all of its blocks and inodes are already valid.
+	 *
+	 * We always allocate group-by-group, then block-by-block or
+	 * inode-by-inode within a group, so enabling these
+	 * blocks/inodes before the group is live won't actually let us
+	 * allocate the new space yet.
+	 */
+	es->s_blocks_count = cpu_to_le32(le32_to_cpu(es->s_blocks_count) +
+		input->blocks_count);
+	es->s_inodes_count = cpu_to_le32(le32_to_cpu(es->s_inodes_count) +
+		EXT3_INODES_PER_GROUP(sb));
+
+	/*
+	 * We need to protect s_groups_count against other CPUs seeing
+	 * inconsistent state in the superblock.
+	 *
+	 * The precise rules we use are:
+	 *
+	 * * Writers of s_groups_count *must* hold lock_super
+	 * AND
+	 * * Writers must perform a smp_wmb() after updating all dependent
+	 *   data and before modifying the groups count
+	 *
+	 * * Readers must hold lock_super() over the access
+	 * OR
+	 * * Readers must perform an smp_rmb() after reading the groups count
+	 *   and before reading any dependent data.
+	 *
+	 * NB. These rules can be relaxed when checking the group count
+	 * while freeing data, as we can only allocate from a block
+	 * group after serialising against the group count, and we can
+	 * only then free after serialising in turn against that
+	 * allocation.
+	 */
+	smp_wmb();
+
+	/* Update the global fs size fields */
+	sbi->s_groups_count++;
+
+	ext3_journal_dirty_metadata(handle, primary);
+
+	/* Update the reserved block counts only once the new group is
+	 * active. */
+	es->s_r_blocks_count = cpu_to_le32(le32_to_cpu(es->s_r_blocks_count) +
+		input->reserved_blocks);
+
+	/* Update the free space counts */
+	percpu_counter_mod(&sbi->s_freeblocks_counter,
+			   input->free_blocks_count);
+	percpu_counter_mod(&sbi->s_freeinodes_counter,
+			   EXT3_INODES_PER_GROUP(sb));
+
+	ext3_journal_dirty_metadata(handle, sbi->s_sbh);
+	sb->s_dirt = 1;
+
+exit_journal:
+	unlock_super(sb);
+	if ((err2 = ext3_journal_stop(handle)) && !err)
+		err = err2;
+	if (!err) {
+		update_backups(sb, sbi->s_sbh->b_blocknr, (char *)es,
+			       sizeof(struct ext3_super_block));
+		update_backups(sb, primary->b_blocknr, primary->b_data,
+			       primary->b_size);
+	}
+exit_put:
+	iput(inode);
+	return err;
+} /* ext3_group_add */
+
+/* Extend the filesystem to the new number of blocks specified.  This entry
+ * point is only used to extend the current filesystem to the end of the last
+ * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
+ * for emergencies (because it has no dependencies on reserved blocks).
+ *
+ * If we _really_ wanted, we could use default values to call ext3_group_add()
+ * allow the "remount" trick to work for arbitrary resizing, assuming enough
+ * GDT blocks are reserved to grow to the desired size.
+ */
+int ext3_group_extend(struct super_block *sb, struct ext3_super_block *es,
+		      ext3_fsblk_t n_blocks_count)
+{
+	ext3_fsblk_t o_blocks_count;
+	unsigned long o_groups_count;
+	ext3_grpblk_t last;
+	ext3_grpblk_t add;
+	struct buffer_head * bh;
+	handle_t *handle;
+	int err;
+	unsigned long freed_blocks;
+
+	/* We don't need to worry about locking wrt other resizers just
+	 * yet: we're going to revalidate es->s_blocks_count after
+	 * taking lock_super() below. */
+	o_blocks_count = le32_to_cpu(es->s_blocks_count);
+	o_groups_count = EXT3_SB(sb)->s_groups_count;
+
+	if (test_opt(sb, DEBUG))
+		printk(KERN_DEBUG "EXT3-fs: extending last group from "E3FSBLK" uto "E3FSBLK" blocks\n",
+		       o_blocks_count, n_blocks_count);
+
+	if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
+		return 0;
+
+	if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
+		printk(KERN_ERR "EXT3-fs: filesystem on %s:"
+			" too large to resize to %lu blocks safely\n",
+			sb->s_id, n_blocks_count);
+		if (sizeof(sector_t) < 8)
+			ext3_warning(sb, __FUNCTION__,
+			"CONFIG_LBD not enabled\n");
+		return -EINVAL;
+	}
+
+	if (n_blocks_count < o_blocks_count) {
+		ext3_warning(sb, __FUNCTION__,
+			     "can't shrink FS - resize aborted");
+		return -EBUSY;
+	}
+
+	/* Handle the remaining blocks in the last group only. */
+	last = (o_blocks_count - le32_to_cpu(es->s_first_data_block)) %
+		EXT3_BLOCKS_PER_GROUP(sb);
+
+	if (last == 0) {
+		ext3_warning(sb, __FUNCTION__,
+			     "need to use ext2online to resize further");
+		return -EPERM;
+	}
+
+	add = EXT3_BLOCKS_PER_GROUP(sb) - last;
+
+	if (o_blocks_count + add < o_blocks_count) {
+		ext3_warning(sb, __FUNCTION__, "blocks_count overflow");
+		return -EINVAL;
+	}
+
+	if (o_blocks_count + add > n_blocks_count)
+		add = n_blocks_count - o_blocks_count;
+
+	if (o_blocks_count + add < n_blocks_count)
+		ext3_warning(sb, __FUNCTION__,
+			     "will only finish group ("E3FSBLK
+			     " blocks, %u new)",
+			     o_blocks_count + add, add);
+
+	/* See if the device is actually as big as what was requested */
+	bh = sb_bread(sb, o_blocks_count + add -1);
+	if (!bh) {
+		ext3_warning(sb, __FUNCTION__,
+			     "can't read last block, resize aborted");
+		return -ENOSPC;
+	}
+	brelse(bh);
+
+	/* We will update the superblock, one block bitmap, and
+	 * one group descriptor via ext3_free_blocks().
+	 */
+	handle = ext3_journal_start_sb(sb, 3);
+	if (IS_ERR(handle)) {
+		err = PTR_ERR(handle);
+		ext3_warning(sb, __FUNCTION__, "error %d on journal start",err);
+		goto exit_put;
+	}
+
+	lock_super(sb);
+	if (o_blocks_count != le32_to_cpu(es->s_blocks_count)) {
+		ext3_warning(sb, __FUNCTION__,
+			     "multiple resizers run on filesystem!");
+		unlock_super(sb);
+		err = -EBUSY;
+		goto exit_put;
+	}
+
+	if ((err = ext3_journal_get_write_access(handle,
+						 EXT3_SB(sb)->s_sbh))) {
+		ext3_warning(sb, __FUNCTION__,
+			     "error %d on journal write access", err);
+		unlock_super(sb);
+		ext3_journal_stop(handle);
+		goto exit_put;
+	}
+	es->s_blocks_count = cpu_to_le32(o_blocks_count + add);
+	ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
+	sb->s_dirt = 1;
+	unlock_super(sb);
+	ext3_debug("freeing blocks %lu through "E3FSBLK"\n", o_blocks_count,
+		   o_blocks_count + add);
+	ext3_free_blocks_sb(handle, sb, o_blocks_count, add, &freed_blocks);
+	ext3_debug("freed blocks "E3FSBLK" through "E3FSBLK"\n", o_blocks_count,
+		   o_blocks_count + add);
+	if ((err = ext3_journal_stop(handle)))
+		goto exit_put;
+	if (test_opt(sb, DEBUG))
+		printk(KERN_DEBUG "EXT3-fs: extended group to %u blocks\n",
+		       le32_to_cpu(es->s_blocks_count));
+	update_backups(sb, EXT3_SB(sb)->s_sbh->b_blocknr, (char *)es,
+		       sizeof(struct ext3_super_block));
+exit_put:
+	return err;
+} /* ext3_group_extend */

fs/ext4/super.c

+/*
+ *  linux/fs/ext3/super.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/inode.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  Big-endian to little-endian byte-swapping/bitmaps by
+ *        David S. Miller (davem@caip.rutgers.edu), 1995
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/time.h>
+#include <linux/jbd.h>
+#include <linux/ext3_fs.h>
+#include <linux/ext3_jbd.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/parser.h>
+#include <linux/smp_lock.h>
+#include <linux/buffer_head.h>
+#include <linux/vfs.h>
+#include <linux/random.h>
+#include <linux/mount.h>
+#include <linux/namei.h>
+#include <linux/quotaops.h>
+#include <linux/seq_file.h>
+
+#include <asm/uaccess.h>
+
+#include "xattr.h"
+#include "acl.h"
+#include "namei.h"
+
+static int ext3_load_journal(struct super_block *, struct ext3_super_block *,
+			     unsigned long journal_devnum);
+static int ext3_create_journal(struct super_block *, struct ext3_super_block *,
+			       unsigned int);
+static void ext3_commit_super (struct super_block * sb,
+			       struct ext3_super_block * es,
+			       int sync);
+static void ext3_mark_recovery_complete(struct super_block * sb,
+					struct ext3_super_block * es);
+static void ext3_clear_journal_err(struct super_block * sb,
+				   struct ext3_super_block * es);
+static int ext3_sync_fs(struct super_block *sb, int wait);
+static const char *ext3_decode_error(struct super_block * sb, int errno,
+				     char nbuf[16]);
+static int ext3_remount (struct super_block * sb, int * flags, char * data);
+static int ext3_statfs (struct dentry * dentry, struct kstatfs * buf);
+static void ext3_unlockfs(struct super_block *sb);
+static void ext3_write_super (struct super_block * sb);
+static void ext3_write_super_lockfs(struct super_block *sb);
+
+/*
+ * Wrappers for journal_start/end.
+ *
+ * The only special thing we need to do here is to make sure that all
+ * journal_end calls result in the superblock being marked dirty, so
+ * that sync() will call the filesystem's write_super callback if
+ * appropriate.
+ */
+handle_t *ext3_journal_start_sb(struct super_block *sb, int nblocks)
+{
+	journal_t *journal;
+
+	if (sb->s_flags & MS_RDONLY)
+		return ERR_PTR(-EROFS);
+
+	/* Special case here: if the journal has aborted behind our
+	 * backs (eg. EIO in the commit thread), then we still need to
+	 * take the FS itself readonly cleanly. */
+	journal = EXT3_SB(sb)->s_journal;
+	if (is_journal_aborted(journal)) {
+		ext3_abort(sb, __FUNCTION__,
+			   "Detected aborted journal");
+		return ERR_PTR(-EROFS);
+	}
+
+	return journal_start(journal, nblocks);
+}
+
+/*
+ * The only special thing we need to do here is to make sure that all
+ * journal_stop calls result in the superblock being marked dirty, so
+ * that sync() will call the filesystem's write_super callback if
+ * appropriate.
+ */
+int __ext3_journal_stop(const char *where, handle_t *handle)
+{
+	struct super_block *sb;
+	int err;
+	int rc;
+
+	sb = handle->h_transaction->t_journal->j_private;
+	err = handle->h_err;
+	rc = journal_stop(handle);
+
+	if (!err)
+		err = rc;
+	if (err)
+		__ext3_std_error(sb, where, err);
+	return err;
+}
+
+void ext3_journal_abort_handle(const char *caller, const char *err_fn,
+		struct buffer_head *bh, handle_t *handle, int err)
+{
+	char nbuf[16];
+	const char *errstr = ext3_decode_error(NULL, err, nbuf);
+
+	if (bh)
+		BUFFER_TRACE(bh, "abort");
+
+	if (!handle->h_err)
+		handle->h_err = err;
+
+	if (is_handle_aborted(handle))
+		return;
+
+	printk(KERN_ERR "%s: aborting transaction: %s in %s\n",
+	       caller, errstr, err_fn);
+
+	journal_abort_handle(handle);
+}
+
+/* Deal with the reporting of failure conditions on a filesystem such as
+ * inconsistencies detected or read IO failures.
+ *
+ * On ext2, we can store the error state of the filesystem in the
+ * superblock.  That is not possible on ext3, because we may have other
+ * write ordering constraints on the superblock which prevent us from
+ * writing it out straight away; and given that the journal is about to
+ * be aborted, we can't rely on the current, or future, transactions to
+ * write out the superblock safely.
+ *
+ * We'll just use the journal_abort() error code to record an error in
+ * the journal instead.  On recovery, the journal will compain about
+ * that error until we've noted it down and cleared it.
+ */
+
+static void ext3_handle_error(struct super_block *sb)
+{
+	struct ext3_super_block *es = EXT3_SB(sb)->s_es;
+
+	EXT3_SB(sb)->s_mount_state |= EXT3_ERROR_FS;
+	es->s_state |= cpu_to_le16(EXT3_ERROR_FS);
+
+	if (sb->s_flags & MS_RDONLY)
+		return;
+
+	if (!test_opt (sb, ERRORS_CONT)) {
+		journal_t *journal = EXT3_SB(sb)->s_journal;
+
+		EXT3_SB(sb)->s_mount_opt |= EXT3_MOUNT_ABORT;
+		if (journal)
+			journal_abort(journal, -EIO);
+	}
+	if (test_opt (sb, ERRORS_RO)) {
+		printk (KERN_CRIT "Remounting filesystem read-only\n");
+		sb->s_flags |= MS_RDONLY;
+	}
+	ext3_commit_super(sb, es, 1);
+	if (test_opt(sb, ERRORS_PANIC))
+		panic("EXT3-fs (device %s): panic forced after error\n",
+			sb->s_id);
+}
+
+void ext3_error (struct super_block * sb, const char * function,
+		 const char * fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	printk(KERN_CRIT "EXT3-fs error (device %s): %s: ",sb->s_id, function);
+	vprintk(fmt, args);
+	printk("\n");
+	va_end(args);
+
+	ext3_handle_error(sb);
+}
+
+static const char *ext3_decode_error(struct super_block * sb, int errno,
+				     char nbuf[16])
+{
+	char *errstr = NULL;
+
+	switch (errno) {
+	case -EIO:
+		errstr = "IO failure";
+		break;
+	case -ENOMEM:
+		errstr = "Out of memory";
+		break;
+	case -EROFS:
+		if (!sb || EXT3_SB(sb)->s_journal->j_flags & JFS_ABORT)
+			errstr = "Journal has aborted";
+		else
+			errstr = "Readonly filesystem";
+		break;
+	default:
+		/* If the caller passed in an extra buffer for unknown
+		 * errors, textualise them now.  Else we just return
+		 * NULL. */
+		if (nbuf) {
+			/* Check for truncated error codes... */
+			if (snprintf(nbuf, 16, "error %d", -errno) >= 0)
+				errstr = nbuf;
+		}
+		break;
+	}
+
+	return errstr;
+}
+
+/* __ext3_std_error decodes expected errors from journaling functions
+ * automatically and invokes the appropriate error response.  */
+
+void __ext3_std_error (struct super_block * sb, const char * function,
+		       int errno)
+{
+	char nbuf[16];
+	const char *errstr;
+
+	/* Special case: if the error is EROFS, and we're not already
+	 * inside a transaction, then there's really no point in logging
+	 * an error. */
+	if (errno == -EROFS && journal_current_handle() == NULL &&
+	    (sb->s_flags & MS_RDONLY))
+		return;
+
+	errstr = ext3_decode_error(sb, errno, nbuf);
+	printk (KERN_CRIT "EXT3-fs error (device %s) in %s: %s\n",
+		sb->s_id, function, errstr);
+
+	ext3_handle_error(sb);
+}
+
+/*
+ * ext3_abort is a much stronger failure handler than ext3_error.  The
+ * abort function may be used to deal with unrecoverable failures such
+ * as journal IO errors or ENOMEM at a critical moment in log management.
+ *
+ * We unconditionally force the filesystem into an ABORT|READONLY state,
+ * unless the error response on the fs has been set to panic in which
+ * case we take the easy way out and panic immediately.
+ */
+
+void ext3_abort (struct super_block * sb, const char * function,
+		 const char * fmt, ...)
+{
+	va_list args;
+
+	printk (KERN_CRIT "ext3_abort called.\n");
+
+	va_start(args, fmt);
+	printk(KERN_CRIT "EXT3-fs error (device %s): %s: ",sb->s_id, function);
+	vprintk(fmt, args);
+	printk("\n");
+	va_end(args);
+
+	if (test_opt(sb, ERRORS_PANIC))
+		panic("EXT3-fs panic from previous error\n");
+
+	if (sb->s_flags & MS_RDONLY)
+		return;
+
+	printk(KERN_CRIT "Remounting filesystem read-only\n");
+	EXT3_SB(sb)->s_mount_state |= EXT3_ERROR_FS;
+	sb->s_flags |= MS_RDONLY;
+	EXT3_SB(sb)->s_mount_opt |= EXT3_MOUNT_ABORT;
+	journal_abort(EXT3_SB(sb)->s_journal, -EIO);
+}
+
+void ext3_warning (struct super_block * sb, const char * function,
+		   const char * fmt, ...)
+{
+	va_list args;
+
+	va_start(args, fmt);
+	printk(KERN_WARNING "EXT3-fs warning (device %s): %s: ",
+	       sb->s_id, function);
+	vprintk(fmt, args);
+	printk("\n");
+	va_end(args);
+}
+
+void ext3_update_dynamic_rev(struct super_block *sb)
+{
+	struct ext3_super_block *es = EXT3_SB(sb)->s_es;
+
+	if (le32_to_cpu(es->s_rev_level) > EXT3_GOOD_OLD_REV)
+		return;
+
+	ext3_warning(sb, __FUNCTION__,
+		     "updating to rev %d because of new feature flag, "
+		     "running e2fsck is recommended",
+		     EXT3_DYNAMIC_REV);
+
+	es->s_first_ino = cpu_to_le32(EXT3_GOOD_OLD_FIRST_INO);
+	es->s_inode_size = cpu_to_le16(EXT3_GOOD_OLD_INODE_SIZE);
+	es->s_rev_level = cpu_to_le32(EXT3_DYNAMIC_REV);
+	/* leave es->s_feature_*compat flags alone */
+	/* es->s_uuid will be set by e2fsck if empty */
+
+	/*
+	 * The rest of the superblock fields should be zero, and if not it
+	 * means they are likely already in use, so leave them alone.  We
+	 * can leave it up to e2fsck to clean up any inconsistencies there.
+	 */
+}
+
+/*
+ * Open the external journal device
+ */
+static struct block_device *ext3_blkdev_get(dev_t dev)
+{
+	struct block_device *bdev;
+	char b[BDEVNAME_SIZE];
+
+	bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE);
+	if (IS_ERR(bdev))
+		goto fail;
+	return bdev;
+
+fail:
+	printk(KERN_ERR "EXT3: failed to open journal device %s: %ld\n",
+			__bdevname(dev, b), PTR_ERR(bdev));
+	return NULL;
+}
+
+/*
+ * Release the journal device
+ */
+static int ext3_blkdev_put(struct block_device *bdev)
+{
+	bd_release(bdev);
+	return blkdev_put(bdev);
+}
+
+static int ext3_blkdev_remove(struct ext3_sb_info *sbi)
+{
+	struct block_device *bdev;
+	int ret = -ENODEV;
+
+	bdev = sbi->journal_bdev;
+	if (bdev) {
+		ret = ext3_blkdev_put(bdev);
+		sbi->journal_bdev = NULL;
+	}
+	return ret;
+}
+
+static inline struct inode *orphan_list_entry(struct list_head *l)
+{
+	return &list_entry(l, struct ext3_inode_info, i_orphan)->vfs_inode;
+}
+
+static void dump_orphan_list(struct super_block *sb, struct ext3_sb_info *sbi)
+{
+	struct list_head *l;
+
+	printk(KERN_ERR "sb orphan head is %d\n",
+	       le32_to_cpu(sbi->s_es->s_last_orphan));
+
+	printk(KERN_ERR "sb_info orphan list:\n");
+	list_for_each(l, &sbi->s_orphan) {
+		struct inode *inode = orphan_list_entry(l);
+		printk(KERN_ERR "  "
+		       "inode %s:%lu at %p: mode %o, nlink %d, next %d\n",
+		       inode->i_sb->s_id, inode->i_ino, inode,
+		       inode->i_mode, inode->i_nlink,
+		       NEXT_ORPHAN(inode));
+	}
+}
+
+static void ext3_put_super (struct super_block * sb)
+{
+	struct ext3_sb_info *sbi = EXT3_SB(sb);
+	struct ext3_super_block *es = sbi->s_es;
+	int i;
+
+	ext3_xattr_put_super(sb);
+	journal_destroy(sbi->s_journal);
+	if (!(sb->s_flags & MS_RDONLY)) {
+		EXT3_CLEAR_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
+		es->s_state = cpu_to_le16(sbi->s_mount_state);
+		BUFFER_TRACE(sbi->s_sbh, "marking dirty");
+		mark_buffer_dirty(sbi->s_sbh);
+		ext3_commit_super(sb, es, 1);
+	}
+
+	for (i = 0; i < sbi->s_gdb_count; i++)
+		brelse(sbi->s_group_desc[i]);
+	kfree(sbi->s_group_desc);
+	percpu_counter_destroy(&sbi->s_freeblocks_counter);
+	percpu_counter_destroy(&sbi->s_freeinodes_counter);
+	percpu_counter_destroy(&sbi->s_dirs_counter);
+	brelse(sbi->s_sbh);
+#ifdef CONFIG_QUOTA
+	for (i = 0; i < MAXQUOTAS; i++)
+		kfree(sbi->s_qf_names[i]);
+#endif
+
+	/* Debugging code just in case the in-memory inode orphan list
+	 * isn't empty.  The on-disk one can be non-empty if we've
+	 * detected an error and taken the fs readonly, but the
+	 * in-memory list had better be clean by this point. */
+	if (!list_empty(&sbi->s_orphan))
+		dump_orphan_list(sb, sbi);
+	J_ASSERT(list_empty(&sbi->s_orphan));
+
+	invalidate_bdev(sb->s_bdev, 0);
+	if (sbi->journal_bdev && sbi->journal_bdev != sb->s_bdev) {
+		/*
+		 * Invalidate the journal device's buffers.  We don't want them
+		 * floating about in memory - the physical journal device may
+		 * hotswapped, and it breaks the `ro-after' testing code.
+		 */
+		sync_blockdev(sbi->journal_bdev);
+		invalidate_bdev(sbi->journal_bdev, 0);
+		ext3_blkdev_remove(sbi);
+	}
+	sb->s_fs_info = NULL;
+	kfree(sbi);
+	return;
+}
+
+static kmem_cache_t *ext3_inode_cachep;
+
+/*
+ * Called inside transaction, so use GFP_NOFS
+ */
+static struct inode *ext3_alloc_inode(struct super_block *sb)
+{
+	struct ext3_inode_info *ei;
+
+	ei = kmem_cache_alloc(ext3_inode_cachep, SLAB_NOFS);
+	if (!ei)
+		return NULL;
+#ifdef CONFIG_EXT3_FS_POSIX_ACL
+	ei->i_acl = EXT3_ACL_NOT_CACHED;
+	ei->i_default_acl = EXT3_ACL_NOT_CACHED;
+#endif
+	ei->i_block_alloc_info = NULL;
+	ei->vfs_inode.i_version = 1;
+	return &ei->vfs_inode;
+}
+
+static void ext3_destroy_inode(struct inode *inode)
+{
+	kmem_cache_free(ext3_inode_cachep, EXT3_I(inode));
+}
+
+static void init_once(void * foo, kmem_cache_t * cachep, unsigned long flags)
+{
+	struct ext3_inode_info *ei = (struct ext3_inode_info *) foo;
+
+	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
+	    SLAB_CTOR_CONSTRUCTOR) {
+		INIT_LIST_HEAD(&ei->i_orphan);
+#ifdef CONFIG_EXT3_FS_XATTR
+		init_rwsem(&ei->xattr_sem);
+#endif
+		mutex_init(&ei->truncate_mutex);
+		inode_init_once(&ei->vfs_inode);
+	}
+}
+
+static int init_inodecache(void)
+{
+	ext3_inode_cachep = kmem_cache_create("ext3_inode_cache",
+					     sizeof(struct ext3_inode_info),
+					     0, (SLAB_RECLAIM_ACCOUNT|
+						SLAB_MEM_SPREAD),
+					     init_once, NULL);
+	if (ext3_inode_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+static void destroy_inodecache(void)
+{
+	kmem_cache_destroy(ext3_inode_cachep);
+}
+
+static void ext3_clear_inode(struct inode *inode)
+{
+	struct ext3_block_alloc_info *rsv = EXT3_I(inode)->i_block_alloc_info;
+#ifdef CONFIG_EXT3_FS_POSIX_ACL
+	if (EXT3_I(inode)->i_acl &&
+			EXT3_I(inode)->i_acl != EXT3_ACL_NOT_CACHED) {
+		posix_acl_release(EXT3_I(inode)->i_acl);
+		EXT3_I(inode)->i_acl = EXT3_ACL_NOT_CACHED;
+	}
+	if (EXT3_I(inode)->i_default_acl &&
+			EXT3_I(inode)->i_default_acl != EXT3_ACL_NOT_CACHED) {
+		posix_acl_release(EXT3_I(inode)->i_default_acl);
+		EXT3_I(inode)->i_default_acl = EXT3_ACL_NOT_CACHED;
+	}
+#endif
+	ext3_discard_reservation(inode);
+	EXT3_I(inode)->i_block_alloc_info = NULL;
+	if (unlikely(rsv))
+		kfree(rsv);
+}
+
+static inline void ext3_show_quota_options(struct seq_file *seq, struct super_block *sb)
+{
+#if defined(CONFIG_QUOTA)
+	struct ext3_sb_info *sbi = EXT3_SB(sb);
+
+	if (sbi->s_jquota_fmt)
+		seq_printf(seq, ",jqfmt=%s",
+		(sbi->s_jquota_fmt == QFMT_VFS_OLD) ? "vfsold": "vfsv0");
+
+	if (sbi->s_qf_names[USRQUOTA])
+		seq_printf(seq, ",usrjquota=%s", sbi->s_qf_names[USRQUOTA]);
+
+	if (sbi->s_qf_names[GRPQUOTA])
+		seq_printf(seq, ",grpjquota=%s", sbi->s_qf_names[GRPQUOTA]);
+
+	if (sbi->s_mount_opt & EXT3_MOUNT_USRQUOTA)
+		seq_puts(seq, ",usrquota");
+
+	if (sbi->s_mount_opt & EXT3_MOUNT_GRPQUOTA)
+		seq_puts(seq, ",grpquota");
+#endif
+}
+
+static int ext3_show_options(struct seq_file *seq, struct vfsmount *vfs)
+{
+	struct super_block *sb = vfs->mnt_sb;
+
+	if (test_opt(sb, DATA_FLAGS) == EXT3_MOUNT_JOURNAL_DATA)
+		seq_puts(seq, ",data=journal");
+	else if (test_opt(sb, DATA_FLAGS) == EXT3_MOUNT_ORDERED_DATA)
+		seq_puts(seq, ",data=ordered");
+	else if (test_opt(sb, DATA_FLAGS) == EXT3_MOUNT_WRITEBACK_DATA)
+		seq_puts(seq, ",data=writeback");
+
+	ext3_show_quota_options(seq, sb);
+
+	return 0;
+}
+
+
+static struct dentry *ext3_get_dentry(struct super_block *sb, void *vobjp)
+{
+	__u32 *objp = vobjp;
+	unsigned long ino = objp[0];
+	__u32 generation = objp[1];
+	struct inode *inode;
+	struct dentry *result;
+
+	if (ino < EXT3_FIRST_INO(sb) && ino != EXT3_ROOT_INO)
+		return ERR_PTR(-ESTALE);
+	if (ino > le32_to_cpu(EXT3_SB(sb)->s_es->s_inodes_count))
+		return ERR_PTR(-ESTALE);
+
+	/* iget isn't really right if the inode is currently unallocated!!
+	 *
+	 * ext3_read_inode will return a bad_inode if the inode had been
+	 * deleted, so we should be safe.
+	 *
+	 * Currently we don't know the generation for parent directory, so
+	 * a generation of 0 means "accept any"
+	 */
+	inode = iget(sb, ino);
+	if (inode == NULL)
+		return ERR_PTR(-ENOMEM);
+	if (is_bad_inode(inode) ||
+	    (generation && inode->i_generation != generation)) {
+		iput(inode);
+		return ERR_PTR(-ESTALE);
+	}
+	/* now to find a dentry.
+	 * If possible, get a well-connected one
+	 */
+	result = d_alloc_anon(inode);
+	if (!result) {
+		iput(inode);
+		return ERR_PTR(-ENOMEM);
+	}
+	return result;
+}
+
+#ifdef CONFIG_QUOTA
+#define QTYPE2NAME(t) ((t)==USRQUOTA?"user":"group")
+#define QTYPE2MOPT(on, t) ((t)==USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
+
+static int ext3_dquot_initialize(struct inode *inode, int type);
+static int ext3_dquot_drop(struct inode *inode);
+static int ext3_write_dquot(struct dquot *dquot);
+static int ext3_acquire_dquot(struct dquot *dquot);
+static int ext3_release_dquot(struct dquot *dquot);
+static int ext3_mark_dquot_dirty(struct dquot *dquot);
+static int ext3_write_info(struct super_block *sb, int type);
+static int ext3_quota_on(struct super_block *sb, int type, int format_id, char *path);
+static int ext3_quota_on_mount(struct super_block *sb, int type);
+static ssize_t ext3_quota_read(struct super_block *sb, int type, char *data,
+			       size_t len, loff_t off);
+static ssize_t ext3_quota_write(struct super_block *sb, int type,
+				const char *data, size_t len, loff_t off);
+
+static struct dquot_operations ext3_quota_operations = {
+	.initialize	= ext3_dquot_initialize,
+	.drop		= ext3_dquot_drop,
+	.alloc_space	= dquot_alloc_space,
+	.alloc_inode	= dquot_alloc_inode,
+	.free_space	= dquot_free_space,
+	.free_inode	= dquot_free_inode,
+	.transfer	= dquot_transfer,
+	.write_dquot	= ext3_write_dquot,
+	.acquire_dquot	= ext3_acquire_dquot,
+	.release_dquot	= ext3_release_dquot,
+	.mark_dirty	= ext3_mark_dquot_dirty,
+	.write_info	= ext3_write_info
+};
+
+static struct quotactl_ops ext3_qctl_operations = {
+	.quota_on	= ext3_quota_on,
+	.quota_off	= vfs_quota_off,
+	.quota_sync	= vfs_quota_sync,
+	.get_info	= vfs_get_dqinfo,
+	.set_info	= vfs_set_dqinfo,
+	.get_dqblk	= vfs_get_dqblk,
+	.set_dqblk	= vfs_set_dqblk
+};
+#endif
+
+static struct super_operations ext3_sops = {
+	.alloc_inode	= ext3_alloc_inode,
+	.destroy_inode	= ext3_destroy_inode,
+	.read_inode	= ext3_read_inode,
+	.write_inode	= ext3_write_inode,
+	.dirty_inode	= ext3_dirty_inode,
+	.delete_inode	= ext3_delete_inode,
+	.put_super	= ext3_put_super,
+	.write_super	= ext3_write_super,
+	.sync_fs	= ext3_sync_fs,
+	.write_super_lockfs = ext3_write_super_lockfs,
+	.unlockfs	= ext3_unlockfs,
+	.statfs		= ext3_statfs,
+	.remount_fs	= ext3_remount,
+	.clear_inode	= ext3_clear_inode,
+	.show_options	= ext3_show_options,
+#ifdef CONFIG_QUOTA
+	.quota_read	= ext3_quota_read,
+	.quota_write	= ext3_quota_write,
+#endif
+};
+
+static struct export_operations ext3_export_ops = {
+	.get_parent = ext3_get_parent,
+	.get_dentry = ext3_get_dentry,
+};
+
+enum {
+	Opt_bsd_df, Opt_minix_df, Opt_grpid, Opt_nogrpid,
+	Opt_resgid, Opt_resuid, Opt_sb, Opt_err_cont, Opt_err_panic, Opt_err_ro,
+	Opt_nouid32, Opt_nocheck, Opt_debug, Opt_oldalloc, Opt_orlov,
+	Opt_user_xattr, Opt_nouser_xattr, Opt_acl, Opt_noacl,
+	Opt_reservation, Opt_noreservation, Opt_noload, Opt_nobh, Opt_bh,
+	Opt_commit, Opt_journal_update, Opt_journal_inum, Opt_journal_dev,
+	Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
+	Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
+	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_quota, Opt_noquota,
+	Opt_ignore, Opt_barrier, Opt_err, Opt_resize, Opt_usrquota,
+	Opt_grpquota
+};
+
+static match_table_t tokens = {
+	{Opt_bsd_df, "bsddf"},
+	{Opt_minix_df, "minixdf"},
+	{Opt_grpid, "grpid"},
+	{Opt_grpid, "bsdgroups"},
+	{Opt_nogrpid, "nogrpid"},
+	{Opt_nogrpid, "sysvgroups"},
+	{Opt_resgid, "resgid=%u"},
+	{Opt_resuid, "resuid=%u"},
+	{Opt_sb, "sb=%u"},
+	{Opt_err_cont, "errors=continue"},
+	{Opt_err_panic, "errors=panic"},
+	{Opt_err_ro, "errors=remount-ro"},
+	{Opt_nouid32, "nouid32"},
+	{Opt_nocheck, "nocheck"},
+	{Opt_nocheck, "check=none"},
+	{Opt_debug, "debug"},
+	{Opt_oldalloc, "oldalloc"},
+	{Opt_orlov, "orlov"},
+	{Opt_user_xattr, "user_xattr"},
+	{Opt_nouser_xattr, "nouser_xattr"},
+	{Opt_acl, "acl"},
+	{Opt_noacl, "noacl"},
+	{Opt_reservation, "reservation"},
+	{Opt_noreservation, "noreservation"},
+	{Opt_noload, "noload"},
+	{Opt_nobh, "nobh"},
+	{Opt_bh, "bh"},
+	{Opt_commit, "commit=%u"},
+	{Opt_journal_update, "journal=update"},
+	{Opt_journal_inum, "journal=%u"},
+	{Opt_journal_dev, "journal_dev=%u"},
+	{Opt_abort, "abort"},
+	{Opt_data_journal, "data=journal"},
+	{Opt_data_ordered, "data=ordered"},
+	{Opt_data_writeback, "data=writeback"},
+	{Opt_offusrjquota, "usrjquota="},
+	{Opt_usrjquota, "usrjquota=%s"},
+	{Opt_offgrpjquota, "grpjquota="},
+	{Opt_grpjquota, "grpjquota=%s"},
+	{Opt_jqfmt_vfsold, "jqfmt=vfsold"},
+	{Opt_jqfmt_vfsv0, "jqfmt=vfsv0"},
+	{Opt_grpquota, "grpquota"},
+	{Opt_noquota, "noquota"},
+	{Opt_quota, "quota"},
+	{Opt_usrquota, "usrquota"},
+	{Opt_barrier, "barrier=%u"},
+	{Opt_err, NULL},
+	{Opt_resize, "resize"},
+};
+
+static ext3_fsblk_t get_sb_block(void **data)
+{
+	ext3_fsblk_t	sb_block;
+	char		*options = (char *) *data;
+
+	if (!options || strncmp(options, "sb=", 3) != 0)
+		return 1;	/* Default location */
+	options += 3;
+	/*todo: use simple_strtoll with >32bit ext3 */
+	sb_block = simple_strtoul(options, &options, 0);
+	if (*options && *options != ',') {
+		printk("EXT3-fs: Invalid sb specification: %s\n",
+		       (char *) *data);
+		return 1;
+	}
+	if (*options == ',')
+		options++;
+	*data = (void *) options;
+	return sb_block;
+}
+
+static int parse_options (char *options, struct super_block *sb,
+			  unsigned int *inum, unsigned long *journal_devnum,
+			  ext3_fsblk_t *n_blocks_count, int is_remount)
+{
+	struct ext3_sb_info *sbi = EXT3_SB(sb);
+	char * p;
+	substring_t args[MAX_OPT_ARGS];
+	int data_opt = 0;
+	int option;
+#ifdef CONFIG_QUOTA
+	int qtype;
+	char *qname;
+#endif
+
+	if (!options)
+		return 1;
+
+	while ((p = strsep (&options, ",")) != NULL) {
+		int token;
+		if (!*p)
+			continue;
+
+		token = match_token(p, tokens, args);
+		switch (token) {
+		case Opt_bsd_df:
+			clear_opt (sbi->s_mount_opt, MINIX_DF);
+			break;
+		case Opt_minix_df:
+			set_opt (sbi->s_mount_opt, MINIX_DF);
+			break;
+		case Opt_grpid:
+			set_opt (sbi->s_mount_opt, GRPID);
+			break;
+		case Opt_nogrpid:
+			clear_opt (sbi->s_mount_opt, GRPID);
+			break;
+		case Opt_resuid:
+			if (match_int(&args[0], &option))
+				return 0;
+			sbi->s_resuid = option;
+			break;
+		case Opt_resgid:
+			if (match_int(&args[0], &option))
+				return 0;
+			sbi->s_resgid = option;
+			break;
+		case Opt_sb:
+			/* handled by get_sb_block() instead of here */
+			/* *sb_block = match_int(&args[0]); */
+			break;
+		case Opt_err_panic:
+			clear_opt (sbi->s_mount_opt, ERRORS_CONT);
+			clear_opt (sbi->s_mount_opt, ERRORS_RO);
+			set_opt (sbi->s_mount_opt, ERRORS_PANIC);
+			break;
+		case Opt_err_ro:
+			clear_opt (sbi->s_mount_opt, ERRORS_CONT);
+			clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
+			set_opt (sbi->s_mount_opt, ERRORS_RO);
+			break;
+		case Opt_err_cont:
+			clear_opt (sbi->s_mount_opt, ERRORS_RO);
+			clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
+			set_opt (sbi->s_mount_opt, ERRORS_CONT);
+			break;
+		case Opt_nouid32:
+			set_opt (sbi->s_mount_opt, NO_UID32);
+			break;
+		case Opt_nocheck:
+			clear_opt (sbi->s_mount_opt, CHECK);
+			break;
+		case Opt_debug:
+			set_opt (sbi->s_mount_opt, DEBUG);
+			break;
+		case Opt_oldalloc:
+			set_opt (sbi->s_mount_opt, OLDALLOC);
+			break;
+		case Opt_orlov:
+			clear_opt (sbi->s_mount_opt, OLDALLOC);
+			break;
+#ifdef CONFIG_EXT3_FS_XATTR
+		case Opt_user_xattr:
+			set_opt (sbi->s_mount_opt, XATTR_USER);
+			break;
+		case Opt_nouser_xattr:
+			clear_opt (sbi->s_mount_opt, XATTR_USER);
+			break;
+#else
+		case Opt_user_xattr:
+		case Opt_nouser_xattr:
+			printk("EXT3 (no)user_xattr options not supported\n");
+			break;
+#endif
+#ifdef CONFIG_EXT3_FS_POSIX_ACL
+		case Opt_acl:
+			set_opt(sbi->s_mount_opt, POSIX_ACL);
+			break;
+		case Opt_noacl:
+			clear_opt(sbi->s_mount_opt, POSIX_ACL);
+			break;
+#else
+		case Opt_acl:
+		case Opt_noacl:
+			printk("EXT3 (no)acl options not supported\n");
+			break;
+#endif
+		case Opt_reservation:
+			set_opt(sbi->s_mount_opt, RESERVATION);
+			break;
+		case Opt_noreservation:
+			clear_opt(sbi->s_mount_opt, RESERVATION);
+			break;
+		case Opt_journal_update:
+			/* @@@ FIXME */
+			/* Eventually we will want to be able to create
+			   a journal file here.  For now, only allow the
+			   user to specify an existing inode to be the
+			   journal file. */
+			if (is_remount) {
+				printk(KERN_ERR "EXT3-fs: cannot specify "
+				       "journal on remount\n");
+				return 0;
+			}
+			set_opt (sbi->s_mount_opt, UPDATE_JOURNAL);
+			break;
+		case Opt_journal_inum:
+			if (is_remount) {
+				printk(KERN_ERR "EXT3-fs: cannot specify "
+				       "journal on remount\n");
+				return 0;
+			}
+			if (match_int(&args[0], &option))
+				return 0;
+			*inum = option;
+			break;
+		case Opt_journal_dev:
+			if (is_remount) {
+				printk(KERN_ERR "EXT3-fs: cannot specify "
+				       "journal on remount\n");
+				return 0;
+			}
+			if (match_int(&args[0], &option))
+				return 0;
+			*journal_devnum = option;
+			break;
+		case Opt_noload:
+			set_opt (sbi->s_mount_opt, NOLOAD);
+			break;
+		case Opt_commit:
+			if (match_int(&args[0], &option))
+				return 0;
+			if (option < 0)
+				return 0;
+			if (option == 0)
+				option = JBD_DEFAULT_MAX_COMMIT_AGE;
+			sbi->s_commit_interval = HZ * option;
+			break;
+		case Opt_data_journal:
+			data_opt = EXT3_MOUNT_JOURNAL_DATA;
+			goto datacheck;
+		case Opt_data_ordered:
+			data_opt = EXT3_MOUNT_ORDERED_DATA;
+			goto datacheck;
+		case Opt_data_writeback:
+			data_opt = EXT3_MOUNT_WRITEBACK_DATA;
+		datacheck:
+			if (is_remount) {
+				if ((sbi->s_mount_opt & EXT3_MOUNT_DATA_FLAGS)
+						!= data_opt) {
+					printk(KERN_ERR
+						"EXT3-fs: cannot change data "
+						"mode on remount\n");
+					return 0;
+				}
+			} else {
+				sbi->s_mount_opt &= ~EXT3_MOUNT_DATA_FLAGS;
+				sbi->s_mount_opt |= data_opt;
+			}
+			break;
+#ifdef CONFIG_QUOTA
+		case Opt_usrjquota:
+			qtype = USRQUOTA;
+			goto set_qf_name;
+		case Opt_grpjquota:
+			qtype = GRPQUOTA;
+set_qf_name:
+			if (sb_any_quota_enabled(sb)) {
+				printk(KERN_ERR
+					"EXT3-fs: Cannot change journalled "
+					"quota options when quota turned on.\n");
+				return 0;
+			}
+			qname = match_strdup(&args[0]);
+			if (!qname) {
+				printk(KERN_ERR
+					"EXT3-fs: not enough memory for "
+					"storing quotafile name.\n");
+				return 0;
+			}
+			if (sbi->s_qf_names[qtype] &&
+			    strcmp(sbi->s_qf_names[qtype], qname)) {
+				printk(KERN_ERR
+					"EXT3-fs: %s quota file already "
+					"specified.\n", QTYPE2NAME(qtype));
+				kfree(qname);
+				return 0;
+			}
+			sbi->s_qf_names[qtype] = qname;
+			if (strchr(sbi->s_qf_names[qtype], '/')) {
+				printk(KERN_ERR
+					"EXT3-fs: quotafile must be on "
+					"filesystem root.\n");
+				kfree(sbi->s_qf_names[qtype]);
+				sbi->s_qf_names[qtype] = NULL;
+				return 0;
+			}
+			set_opt(sbi->s_mount_opt, QUOTA);
+			break;
+		case Opt_offusrjquota:
+			qtype = USRQUOTA;
+			goto clear_qf_name;
+		case Opt_offgrpjquota:
+			qtype = GRPQUOTA;
+clear_qf_name:
+			if (sb_any_quota_enabled(sb)) {
+				printk(KERN_ERR "EXT3-fs: Cannot change "
+					"journalled quota options when "
+					"quota turned on.\n");
+				return 0;
+			}
+			/*
+			 * The space will be released later when all options
+			 * are confirmed to be correct
+			 */
+			sbi->s_qf_names[qtype] = NULL;
+			break;
+		case Opt_jqfmt_vfsold:
+			sbi->s_jquota_fmt = QFMT_VFS_OLD;
+			break;
+		case Opt_jqfmt_vfsv0:
+			sbi->s_jquota_fmt = QFMT_VFS_V0;
+			break;
+		case Opt_quota:
+		case Opt_usrquota:
+			set_opt(sbi->s_mount_opt, QUOTA);
+			set_opt(sbi->s_mount_opt, USRQUOTA);
+			break;
+		case Opt_grpquota:
+			set_opt(sbi->s_mount_opt, QUOTA);
+			set_opt(sbi->s_mount_opt, GRPQUOTA);
+			break;
+		case Opt_noquota:
+			if (sb_any_quota_enabled(sb)) {
+				printk(KERN_ERR "EXT3-fs: Cannot change quota "
+					"options when quota turned on.\n");
+				return 0;
+			}
+			clear_opt(sbi->s_mount_opt, QUOTA);
+			clear_opt(sbi->s_mount_opt, USRQUOTA);
+			clear_opt(sbi->s_mount_opt, GRPQUOTA);
+			break;
+#else
+		case Opt_quota:
+		case Opt_usrquota:
+		case Opt_grpquota:
+		case Opt_usrjquota:
+		case Opt_grpjquota:
+		case Opt_offusrjquota:
+		case Opt_offgrpjquota:
+		case Opt_jqfmt_vfsold:
+		case Opt_jqfmt_vfsv0:
+			printk(KERN_ERR
+				"EXT3-fs: journalled quota options not "
+				"supported.\n");
+			break;
+		case Opt_noquota:
+			break;
+#endif
+		case Opt_abort:
+			set_opt(sbi->s_mount_opt, ABORT);
+			break;
+		case Opt_barrier:
+			if (match_int(&args[0], &option))
+				return 0;
+			if (option)
+				set_opt(sbi->s_mount_opt, BARRIER);
+			else
+				clear_opt(sbi->s_mount_opt, BARRIER);
+			break;
+		case Opt_ignore:
+			break;
+		case Opt_resize:
+			if (!is_remount) {
+				printk("EXT3-fs: resize option only available "
+					"for remount\n");
+				return 0;
+			}
+			if (match_int(&args[0], &option) != 0)
+				return 0;
+			*n_blocks_count = option;
+			break;
+		case Opt_nobh:
+			set_opt(sbi->s_mount_opt, NOBH);
+			break;
+		case Opt_bh:
+			clear_opt(sbi->s_mount_opt, NOBH);
+			break;
+		default:
+			printk (KERN_ERR
+				"EXT3-fs: Unrecognized mount option \"%s\" "
+				"or missing value\n", p);
+			return 0;
+		}
+	}
+#ifdef CONFIG_QUOTA
+	if (sbi->s_qf_names[USRQUOTA] || sbi->s_qf_names[GRPQUOTA]) {
+		if ((sbi->s_mount_opt & EXT3_MOUNT_USRQUOTA) &&
+		     sbi->s_qf_names[USRQUOTA])
+			clear_opt(sbi->s_mount_opt, USRQUOTA);
+
+		if ((sbi->s_mount_opt & EXT3_MOUNT_GRPQUOTA) &&
+		     sbi->s_qf_names[GRPQUOTA])
+			clear_opt(sbi->s_mount_opt, GRPQUOTA);
+
+		if ((sbi->s_qf_names[USRQUOTA] &&
+				(sbi->s_mount_opt & EXT3_MOUNT_GRPQUOTA)) ||
+		    (sbi->s_qf_names[GRPQUOTA] &&
+				(sbi->s_mount_opt & EXT3_MOUNT_USRQUOTA))) {
+			printk(KERN_ERR "EXT3-fs: old and new quota "
+					"format mixing.\n");
+			return 0;
+		}
+
+		if (!sbi->s_jquota_fmt) {
+			printk(KERN_ERR "EXT3-fs: journalled quota format "
+					"not specified.\n");
+			return 0;
+		}
+	} else {
+		if (sbi->s_jquota_fmt) {
+			printk(KERN_ERR "EXT3-fs: journalled quota format "
+					"specified with no journalling "
+					"enabled.\n");
+			return 0;
+		}
+	}
+#endif
+	return 1;
+}
+
+static int ext3_setup_super(struct super_block *sb, struct ext3_super_block *es,
+			    int read_only)
+{
+	struct ext3_sb_info *sbi = EXT3_SB(sb);
+	int res = 0;
+
+	if (le32_to_cpu(es->s_rev_level) > EXT3_MAX_SUPP_REV) {
+		printk (KERN_ERR "EXT3-fs warning: revision level too high, "
+			"forcing read-only mode\n");
+		res = MS_RDONLY;
+	}
+	if (read_only)
+		return res;
+	if (!(sbi->s_mount_state & EXT3_VALID_FS))
+		printk (KERN_WARNING "EXT3-fs warning: mounting unchecked fs, "
+			"running e2fsck is recommended\n");
+	else if ((sbi->s_mount_state & EXT3_ERROR_FS))
+		printk (KERN_WARNING
+			"EXT3-fs warning: mounting fs with errors, "
+			"running e2fsck is recommended\n");
+	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
+		 le16_to_cpu(es->s_mnt_count) >=
+		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
+		printk (KERN_WARNING
+			"EXT3-fs warning: maximal mount count reached, "
+			"running e2fsck is recommended\n");
+	else if (le32_to_cpu(es->s_checkinterval) &&
+		(le32_to_cpu(es->s_lastcheck) +
+			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
+		printk (KERN_WARNING
+			"EXT3-fs warning: checktime reached, "
+			"running e2fsck is recommended\n");
+#if 0
+		/* @@@ We _will_ want to clear the valid bit if we find
+                   inconsistencies, to force a fsck at reboot.  But for
+                   a plain journaled filesystem we can keep it set as
+                   valid forever! :) */
+	es->s_state = cpu_to_le16(le16_to_cpu(es->s_state) & ~EXT3_VALID_FS);
+#endif
+	if (!(__s16) le16_to_cpu(es->s_max_mnt_count))
+		es->s_max_mnt_count = cpu_to_le16(EXT3_DFL_MAX_MNT_COUNT);
+	es->s_mnt_count=cpu_to_le16(le16_to_cpu(es->s_mnt_count) + 1);
+	es->s_mtime = cpu_to_le32(get_seconds());
+	ext3_update_dynamic_rev(sb);
+	EXT3_SET_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
+
+	ext3_commit_super(sb, es, 1);
+	if (test_opt(sb, DEBUG))
+		printk(KERN_INFO "[EXT3 FS bs=%lu, gc=%lu, "
+				"bpg=%lu, ipg=%lu, mo=%04lx]\n",
+			sb->s_blocksize,
+			sbi->s_groups_count,
+			EXT3_BLOCKS_PER_GROUP(sb),
+			EXT3_INODES_PER_GROUP(sb),
+			sbi->s_mount_opt);
+
+	printk(KERN_INFO "EXT3 FS on %s, ", sb->s_id);
+	if (EXT3_SB(sb)->s_journal->j_inode == NULL) {
+		char b[BDEVNAME_SIZE];
+
+		printk("external journal on %s\n",
+			bdevname(EXT3_SB(sb)->s_journal->j_dev, b));
+	} else {
+		printk("internal journal\n");
+	}
+	return res;
+}
+
+/* Called at mount-time, super-block is locked */
+static int ext3_check_descriptors (struct super_block * sb)
+{
+	struct ext3_sb_info *sbi = EXT3_SB(sb);
+	ext3_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
+	ext3_fsblk_t last_block;
+	struct ext3_group_desc * gdp = NULL;
+	int desc_block = 0;
+	int i;
+
+	ext3_debug ("Checking group descriptors");
+
+	for (i = 0; i < sbi->s_groups_count; i++)
+	{
+		if (i == sbi->s_groups_count - 1)
+			last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
+		else
+			last_block = first_block +
+				(EXT3_BLOCKS_PER_GROUP(sb) - 1);
+
+		if ((i % EXT3_DESC_PER_BLOCK(sb)) == 0)
+			gdp = (struct ext3_group_desc *)
+					sbi->s_group_desc[desc_block++]->b_data;
+		if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
+		    le32_to_cpu(gdp->bg_block_bitmap) > last_block)
+		{
+			ext3_error (sb, "ext3_check_descriptors",
+				    "Block bitmap for group %d"
+				    " not in group (block %lu)!",
+				    i, (unsigned long)
+					le32_to_cpu(gdp->bg_block_bitmap));
+			return 0;
+		}
+		if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
+		    le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
+		{
+			ext3_error (sb, "ext3_check_descriptors",
+				    "Inode bitmap for group %d"
+				    " not in group (block %lu)!",
+				    i, (unsigned long)
+					le32_to_cpu(gdp->bg_inode_bitmap));
+			return 0;
+		}
+		if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
+		    le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >
+		    last_block)
+		{
+			ext3_error (sb, "ext3_check_descriptors",
+				    "Inode table for group %d"
+				    " not in group (block %lu)!",
+				    i, (unsigned long)
+					le32_to_cpu(gdp->bg_inode_table));
+			return 0;
+		}
+		first_block += EXT3_BLOCKS_PER_GROUP(sb);
+		gdp++;
+	}
+
+	sbi->s_es->s_free_blocks_count=cpu_to_le32(ext3_count_free_blocks(sb));
+	sbi->s_es->s_free_inodes_count=cpu_to_le32(ext3_count_free_inodes(sb));
+	return 1;
+}
+
+
+/* ext3_orphan_cleanup() walks a singly-linked list of inodes (starting at
+ * the superblock) which were deleted from all directories, but held open by
+ * a process at the time of a crash.  We walk the list and try to delete these
+ * inodes at recovery time (only with a read-write filesystem).
+ *
+ * In order to keep the orphan inode chain consistent during traversal (in
+ * case of crash during recovery), we link each inode into the superblock
+ * orphan list_head and handle it the same way as an inode deletion during
+ * normal operation (which journals the operations for us).
+ *
+ * We only do an iget() and an iput() on each inode, which is very safe if we
+ * accidentally point at an in-use or already deleted inode.  The worst that
+ * can happen in this case is that we get a "bit already cleared" message from
+ * ext3_free_inode().  The only reason we would point at a wrong inode is if
+ * e2fsck was run on this filesystem, and it must have already done the orphan
+ * inode cleanup for us, so we can safely abort without any further action.
+ */
+static void ext3_orphan_cleanup (struct super_block * sb,
+				 struct ext3_super_block * es)
+{
+	unsigned int s_flags = sb->s_flags;
+	int nr_orphans = 0, nr_truncates = 0;
+#ifdef CONFIG_QUOTA
+	int i;
+#endif
+	if (!es->s_last_orphan) {
+		jbd_debug(4, "no orphan inodes to clean up\n");
+		return;
+	}
+
+	if (EXT3_SB(sb)->s_mount_state & EXT3_ERROR_FS) {
+		if (es->s_last_orphan)
+			jbd_debug(1, "Errors on filesystem, "
+				  "clearing orphan list.\n");
+		es->s_last_orphan = 0;
+		jbd_debug(1, "Skipping orphan recovery on fs with errors.\n");
+		return;
+	}
+
+	if (s_flags & MS_RDONLY) {
+		printk(KERN_INFO "EXT3-fs: %s: orphan cleanup on readonly fs\n",
+		       sb->s_id);
+		sb->s_flags &= ~MS_RDONLY;
+	}
+#ifdef CONFIG_QUOTA
+	/* Needed for iput() to work correctly and not trash data */
+	sb->s_flags |= MS_ACTIVE;
+	/* Turn on quotas so that they are updated correctly */
+	for (i = 0; i < MAXQUOTAS; i++) {
+		if (EXT3_SB(sb)->s_qf_names[i]) {
+			int ret = ext3_quota_on_mount(sb, i);
+			if (ret < 0)
+				printk(KERN_ERR
+					"EXT3-fs: Cannot turn on journalled "
+					"quota: error %d\n", ret);
+		}
+	}
+#endif
+
+	while (es->s_last_orphan) {
+		struct inode *inode;
+
+		if (!(inode =
+		      ext3_orphan_get(sb, le32_to_cpu(es->s_last_orphan)))) {
+			es->s_last_orphan = 0;
+			break;
+		}
+
+		list_add(&EXT3_I(inode)->i_orphan, &EXT3_SB(sb)->s_orphan);
+		DQUOT_INIT(inode);
+		if (inode->i_nlink) {
+			printk(KERN_DEBUG
+				"%s: truncating inode %lu to %Ld bytes\n",
+				__FUNCTION__, inode->i_ino, inode->i_size);
+			jbd_debug(2, "truncating inode %lu to %Ld bytes\n",
+				  inode->i_ino, inode->i_size);
+			ext3_truncate(inode);
+			nr_truncates++;
+		} else {
+			printk(KERN_DEBUG
+				"%s: deleting unreferenced inode %lu\n",
+				__FUNCTION__, inode->i_ino);
+			jbd_debug(2, "deleting unreferenced inode %lu\n",
+				  inode->i_ino);
+			nr_orphans++;
+		}
+		iput(inode);  /* The delete magic happens here! */
+	}
+
+#define PLURAL(x) (x), ((x)==1) ? "" : "s"
+
+	if (nr_orphans)
+		printk(KERN_INFO "EXT3-fs: %s: %d orphan inode%s deleted\n",
+		       sb->s_id, PLURAL(nr_orphans));
+	if (nr_truncates)
+		printk(KERN_INFO "EXT3-fs: %s: %d truncate%s cleaned up\n",
+		       sb->s_id, PLURAL(nr_truncates));
+#ifdef CONFIG_QUOTA
+	/* Turn quotas off */
+	for (i = 0; i < MAXQUOTAS; i++) {
+		if (sb_dqopt(sb)->files[i])
+			vfs_quota_off(sb, i);
+	}
+#endif
+	sb->s_flags = s_flags; /* Restore MS_RDONLY status */
+}
+
+#define log2(n) ffz(~(n))
+
+/*
+ * Maximal file size.  There is a direct, and {,double-,triple-}indirect
+ * block limit, and also a limit of (2^32 - 1) 512-byte sectors in i_blocks.
+ * We need to be 1 filesystem block less than the 2^32 sector limit.
+ */
+static loff_t ext3_max_size(int bits)
+{
+	loff_t res = EXT3_NDIR_BLOCKS;
+	/* This constant is calculated to be the largest file size for a
+	 * dense, 4k-blocksize file such that the total number of
+	 * sectors in the file, including data and all indirect blocks,
+	 * does not exceed 2^32. */
+	const loff_t upper_limit = 0x1ff7fffd000LL;
+
+	res += 1LL << (bits-2);
+	res += 1LL << (2*(bits-2));
+	res += 1LL << (3*(bits-2));
+	res <<= bits;
+	if (res > upper_limit)
+		res = upper_limit;
+	return res;
+}
+
+static ext3_fsblk_t descriptor_loc(struct super_block *sb,
+				    ext3_fsblk_t logic_sb_block,
+				    int nr)
+{
+	struct ext3_sb_info *sbi = EXT3_SB(sb);
+	unsigned long bg, first_meta_bg;
+	int has_super = 0;
+
+	first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
+
+	if (!EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_META_BG) ||
+	    nr < first_meta_bg)
+		return (logic_sb_block + nr + 1);
+	bg = sbi->s_desc_per_block * nr;
+	if (ext3_bg_has_super(sb, bg))
+		has_super = 1;
+	return (has_super + ext3_group_first_block_no(sb, bg));
+}
+
+
+static int ext3_fill_super (struct super_block *sb, void *data, int silent)
+{
+	struct buffer_head * bh;
+	struct ext3_super_block *es = NULL;
+	struct ext3_sb_info *sbi;
+	ext3_fsblk_t block;
+	ext3_fsblk_t sb_block = get_sb_block(&data);
+	ext3_fsblk_t logic_sb_block;
+	unsigned long offset = 0;
+	unsigned int journal_inum = 0;
+	unsigned long journal_devnum = 0;
+	unsigned long def_mount_opts;
+	struct inode *root;
+	int blocksize;
+	int hblock;
+	int db_count;
+	int i;
+	int needs_recovery;
+	__le32 features;
+
+	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
+	if (!sbi)
+		return -ENOMEM;
+	sb->s_fs_info = sbi;
+	sbi->s_mount_opt = 0;
+	sbi->s_resuid = EXT3_DEF_RESUID;
+	sbi->s_resgid = EXT3_DEF_RESGID;
+
+	unlock_kernel();
+
+	blocksize = sb_min_blocksize(sb, EXT3_MIN_BLOCK_SIZE);
+	if (!blocksize) {
+		printk(KERN_ERR "EXT3-fs: unable to set blocksize\n");
+		goto out_fail;
+	}
+
+	/*
+	 * The ext3 superblock will not be buffer aligned for other than 1kB
+	 * block sizes.  We need to calculate the offset from buffer start.
+	 */
+	if (blocksize != EXT3_MIN_BLOCK_SIZE) {
+		logic_sb_block = (sb_block * EXT3_MIN_BLOCK_SIZE) / blocksize;
+		offset = (sb_block * EXT3_MIN_BLOCK_SIZE) % blocksize;
+	} else {
+		logic_sb_block = sb_block;
+	}
+
+	if (!(bh = sb_bread(sb, logic_sb_block))) {
+		printk (KERN_ERR "EXT3-fs: unable to read superblock\n");
+		goto out_fail;
+	}
+	/*
+	 * Note: s_es must be initialized as soon as possible because
+	 *       some ext3 macro-instructions depend on its value
+	 */
+	es = (struct ext3_super_block *) (((char *)bh->b_data) + offset);
+	sbi->s_es = es;
+	sb->s_magic = le16_to_cpu(es->s_magic);
+	if (sb->s_magic != EXT3_SUPER_MAGIC)
+		goto cantfind_ext3;
+
+	/* Set defaults before we parse the mount options */
+	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
+	if (def_mount_opts & EXT3_DEFM_DEBUG)
+		set_opt(sbi->s_mount_opt, DEBUG);
+	if (def_mount_opts & EXT3_DEFM_BSDGROUPS)
+		set_opt(sbi->s_mount_opt, GRPID);
+	if (def_mount_opts & EXT3_DEFM_UID16)
+		set_opt(sbi->s_mount_opt, NO_UID32);
+	if (def_mount_opts & EXT3_DEFM_XATTR_USER)
+		set_opt(sbi->s_mount_opt, XATTR_USER);
+	if (def_mount_opts & EXT3_DEFM_ACL)
+		set_opt(sbi->s_mount_opt, POSIX_ACL);
+	if ((def_mount_opts & EXT3_DEFM_JMODE) == EXT3_DEFM_JMODE_DATA)
+		sbi->s_mount_opt |= EXT3_MOUNT_JOURNAL_DATA;
+	else if ((def_mount_opts & EXT3_DEFM_JMODE) == EXT3_DEFM_JMODE_ORDERED)
+		sbi->s_mount_opt |= EXT3_MOUNT_ORDERED_DATA;
+	else if ((def_mount_opts & EXT3_DEFM_JMODE) == EXT3_DEFM_JMODE_WBACK)
+		sbi->s_mount_opt |= EXT3_MOUNT_WRITEBACK_DATA;
+
+	if (le16_to_cpu(sbi->s_es->s_errors) == EXT3_ERRORS_PANIC)
+		set_opt(sbi->s_mount_opt, ERRORS_PANIC);
+	else if (le16_to_cpu(sbi->s_es->s_errors) == EXT3_ERRORS_RO)
+		set_opt(sbi->s_mount_opt, ERRORS_RO);
+
+	sbi->s_resuid = le16_to_cpu(es->s_def_resuid);
+	sbi->s_resgid = le16_to_cpu(es->s_def_resgid);
+
+	set_opt(sbi->s_mount_opt, RESERVATION);
+
+	if (!parse_options ((char *) data, sb, &journal_inum, &journal_devnum,
+			    NULL, 0))
+		goto failed_mount;
+
+	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
+		((sbi->s_mount_opt & EXT3_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
+
+	if (le32_to_cpu(es->s_rev_level) == EXT3_GOOD_OLD_REV &&
+	    (EXT3_HAS_COMPAT_FEATURE(sb, ~0U) ||
+	     EXT3_HAS_RO_COMPAT_FEATURE(sb, ~0U) ||
+	     EXT3_HAS_INCOMPAT_FEATURE(sb, ~0U)))
+		printk(KERN_WARNING
+		       "EXT3-fs warning: feature flags set on rev 0 fs, "
+		       "running e2fsck is recommended\n");
+	/*
+	 * Check feature flags regardless of the revision level, since we
+	 * previously didn't change the revision level when setting the flags,
+	 * so there is a chance incompat flags are set on a rev 0 filesystem.
+	 */
+	features = EXT3_HAS_INCOMPAT_FEATURE(sb, ~EXT3_FEATURE_INCOMPAT_SUPP);
+	if (features) {
+		printk(KERN_ERR "EXT3-fs: %s: couldn't mount because of "
+		       "unsupported optional features (%x).\n",
+		       sb->s_id, le32_to_cpu(features));
+		goto failed_mount;
+	}
+	features = EXT3_HAS_RO_COMPAT_FEATURE(sb, ~EXT3_FEATURE_RO_COMPAT_SUPP);
+	if (!(sb->s_flags & MS_RDONLY) && features) {
+		printk(KERN_ERR "EXT3-fs: %s: couldn't mount RDWR because of "
+		       "unsupported optional features (%x).\n",
+		       sb->s_id, le32_to_cpu(features));
+		goto failed_mount;
+	}
+	blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
+
+	if (blocksize < EXT3_MIN_BLOCK_SIZE ||
+	    blocksize > EXT3_MAX_BLOCK_SIZE) {
+		printk(KERN_ERR
+		       "EXT3-fs: Unsupported filesystem blocksize %d on %s.\n",
+		       blocksize, sb->s_id);
+		goto failed_mount;
+	}
+
+	hblock = bdev_hardsect_size(sb->s_bdev);
+	if (sb->s_blocksize != blocksize) {
+		/*
+		 * Make sure the blocksize for the filesystem is larger
+		 * than the hardware sectorsize for the machine.
+		 */
+		if (blocksize < hblock) {
+			printk(KERN_ERR "EXT3-fs: blocksize %d too small for "
+			       "device blocksize %d.\n", blocksize, hblock);
+			goto failed_mount;
+		}
+
+		brelse (bh);
+		sb_set_blocksize(sb, blocksize);
+		logic_sb_block = (sb_block * EXT3_MIN_BLOCK_SIZE) / blocksize;
+		offset = (sb_block * EXT3_MIN_BLOCK_SIZE) % blocksize;
+		bh = sb_bread(sb, logic_sb_block);
+		if (!bh) {
+			printk(KERN_ERR
+			       "EXT3-fs: Can't read superblock on 2nd try.\n");
+			goto failed_mount;
+		}
+		es = (struct ext3_super_block *)(((char *)bh->b_data) + offset);
+		sbi->s_es = es;
+		if (es->s_magic != cpu_to_le16(EXT3_SUPER_MAGIC)) {
+			printk (KERN_ERR
+				"EXT3-fs: Magic mismatch, very weird !\n");
+			goto failed_mount;
+		}
+	}
+
+	sb->s_maxbytes = ext3_max_size(sb->s_blocksize_bits);
+
+	if (le32_to_cpu(es->s_rev_level) == EXT3_GOOD_OLD_REV) {
+		sbi->s_inode_size = EXT3_GOOD_OLD_INODE_SIZE;
+		sbi->s_first_ino = EXT3_GOOD_OLD_FIRST_INO;
+	} else {
+		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
+		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
+		if ((sbi->s_inode_size < EXT3_GOOD_OLD_INODE_SIZE) ||
+		    (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
+		    (sbi->s_inode_size > blocksize)) {
+			printk (KERN_ERR
+				"EXT3-fs: unsupported inode size: %d\n",
+				sbi->s_inode_size);
+			goto failed_mount;
+		}
+	}
+	sbi->s_frag_size = EXT3_MIN_FRAG_SIZE <<
+				   le32_to_cpu(es->s_log_frag_size);
+	if (blocksize != sbi->s_frag_size) {
+		printk(KERN_ERR
+		       "EXT3-fs: fragsize %lu != blocksize %u (unsupported)\n",
+		       sbi->s_frag_size, blocksize);
+		goto failed_mount;
+	}
+	sbi->s_frags_per_block = 1;
+	sbi->s_blocks_per_group = le32_to_cpu(es->s_blocks_per_group);
+	sbi->s_frags_per_group = le32_to_cpu(es->s_frags_per_group);
+	sbi->s_inodes_per_group = le32_to_cpu(es->s_inodes_per_group);
+	if (EXT3_INODE_SIZE(sb) == 0)
+		goto cantfind_ext3;
+	sbi->s_inodes_per_block = blocksize / EXT3_INODE_SIZE(sb);
+	if (sbi->s_inodes_per_block == 0)
+		goto cantfind_ext3;
+	sbi->s_itb_per_group = sbi->s_inodes_per_group /
+					sbi->s_inodes_per_block;
+	sbi->s_desc_per_block = blocksize / sizeof(struct ext3_group_desc);
+	sbi->s_sbh = bh;
+	sbi->s_mount_state = le16_to_cpu(es->s_state);
+	sbi->s_addr_per_block_bits = log2(EXT3_ADDR_PER_BLOCK(sb));
+	sbi->s_desc_per_block_bits = log2(EXT3_DESC_PER_BLOCK(sb));
+	for (i=0; i < 4; i++)
+		sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
+	sbi->s_def_hash_version = es->s_def_hash_version;
+
+	if (sbi->s_blocks_per_group > blocksize * 8) {
+		printk (KERN_ERR
+			"EXT3-fs: #blocks per group too big: %lu\n",
+			sbi->s_blocks_per_group);
+		goto failed_mount;
+	}
+	if (sbi->s_frags_per_group > blocksize * 8) {
+		printk (KERN_ERR
+			"EXT3-fs: #fragments per group too big: %lu\n",
+			sbi->s_frags_per_group);
+		goto failed_mount;
+	}
+	if (sbi->s_inodes_per_group > blocksize * 8) {
+		printk (KERN_ERR
+			"EXT3-fs: #inodes per group too big: %lu\n",
+			sbi->s_inodes_per_group);
+		goto failed_mount;
+	}
+
+	if (le32_to_cpu(es->s_blocks_count) >
+		    (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
+		printk(KERN_ERR "EXT3-fs: filesystem on %s:"
+			" too large to mount safely\n", sb->s_id);
+		if (sizeof(sector_t) < 8)
+			printk(KERN_WARNING "EXT3-fs: CONFIG_LBD not "
+					"enabled\n");
+		goto failed_mount;
+	}
+
+	if (EXT3_BLOCKS_PER_GROUP(sb) == 0)
+		goto cantfind_ext3;
+	sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
+			       le32_to_cpu(es->s_first_data_block) - 1)
+				       / EXT3_BLOCKS_PER_GROUP(sb)) + 1;
+	db_count = (sbi->s_groups_count + EXT3_DESC_PER_BLOCK(sb) - 1) /
+		   EXT3_DESC_PER_BLOCK(sb);
+	sbi->s_group_desc = kmalloc(db_count * sizeof (struct buffer_head *),
+				    GFP_KERNEL);
+	if (sbi->s_group_desc == NULL) {
+		printk (KERN_ERR "EXT3-fs: not enough memory\n");
+		goto failed_mount;
+	}
+
+	bgl_lock_init(&sbi->s_blockgroup_lock);
+
+	for (i = 0; i < db_count; i++) {
+		block = descriptor_loc(sb, logic_sb_block, i);
+		sbi->s_group_desc[i] = sb_bread(sb, block);
+		if (!sbi->s_group_desc[i]) {
+			printk (KERN_ERR "EXT3-fs: "
+				"can't read group descriptor %d\n", i);
+			db_count = i;
+			goto failed_mount2;
+		}
+	}
+	if (!ext3_check_descriptors (sb)) {
+		printk(KERN_ERR "EXT3-fs: group descriptors corrupted!\n");
+		goto failed_mount2;
+	}
+	sbi->s_gdb_count = db_count;
+	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
+	spin_lock_init(&sbi->s_next_gen_lock);
+
+	percpu_counter_init(&sbi->s_freeblocks_counter,
+		ext3_count_free_blocks(sb));
+	percpu_counter_init(&sbi->s_freeinodes_counter,
+		ext3_count_free_inodes(sb));
+	percpu_counter_init(&sbi->s_dirs_counter,
+		ext3_count_dirs(sb));
+
+	/* per fileystem reservation list head & lock */
+	spin_lock_init(&sbi->s_rsv_window_lock);
+	sbi->s_rsv_window_root = RB_ROOT;
+	/* Add a single, static dummy reservation to the start of the
+	 * reservation window list --- it gives us a placeholder for
+	 * append-at-start-of-list which makes the allocation logic
+	 * _much_ simpler. */
+	sbi->s_rsv_window_head.rsv_start = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
+	sbi->s_rsv_window_head.rsv_end = EXT3_RESERVE_WINDOW_NOT_ALLOCATED;
+	sbi->s_rsv_window_head.rsv_alloc_hit = 0;
+	sbi->s_rsv_window_head.rsv_goal_size = 0;
+	ext3_rsv_window_add(sb, &sbi->s_rsv_window_head);
+
+	/*
+	 * set up enough so that it can read an inode
+	 */
+	sb->s_op = &ext3_sops;
+	sb->s_export_op = &ext3_export_ops;
+	sb->s_xattr = ext3_xattr_handlers;
+#ifdef CONFIG_QUOTA
+	sb->s_qcop = &ext3_qctl_operations;
+	sb->dq_op = &ext3_quota_operations;
+#endif
+	INIT_LIST_HEAD(&sbi->s_orphan); /* unlinked but open files */
+
+	sb->s_root = NULL;
+
+	needs_recovery = (es->s_last_orphan != 0 ||
+			  EXT3_HAS_INCOMPAT_FEATURE(sb,
+				    EXT3_FEATURE_INCOMPAT_RECOVER));
+
+	/*
+	 * The first inode we look at is the journal inode.  Don't try
+	 * root first: it may be modified in the journal!
+	 */
+	if (!test_opt(sb, NOLOAD) &&
+	    EXT3_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL)) {
+		if (ext3_load_journal(sb, es, journal_devnum))
+			goto failed_mount3;
+	} else if (journal_inum) {
+		if (ext3_create_journal(sb, es, journal_inum))
+			goto failed_mount3;
+	} else {
+		if (!silent)
+			printk (KERN_ERR
+				"ext3: No journal on filesystem on %s\n",
+				sb->s_id);
+		goto failed_mount3;
+	}
+
+	/* We have now updated the journal if required, so we can
+	 * validate the data journaling mode. */
+	switch (test_opt(sb, DATA_FLAGS)) {
+	case 0:
+		/* No mode set, assume a default based on the journal
+                   capabilities: ORDERED_DATA if the journal can
+                   cope, else JOURNAL_DATA */
+		if (journal_check_available_features
+		    (sbi->s_journal, 0, 0, JFS_FEATURE_INCOMPAT_REVOKE))
+			set_opt(sbi->s_mount_opt, ORDERED_DATA);
+		else
+			set_opt(sbi->s_mount_opt, JOURNAL_DATA);
+		break;
+
+	case EXT3_MOUNT_ORDERED_DATA:
+	case EXT3_MOUNT_WRITEBACK_DATA:
+		if (!journal_check_available_features
+		    (sbi->s_journal, 0, 0, JFS_FEATURE_INCOMPAT_REVOKE)) {
+			printk(KERN_ERR "EXT3-fs: Journal does not support "
+			       "requested data journaling mode\n");
+			goto failed_mount4;
+		}
+	default:
+		break;
+	}
+
+	if (test_opt(sb, NOBH)) {
+		if (!(test_opt(sb, DATA_FLAGS) == EXT3_MOUNT_WRITEBACK_DATA)) {
+			printk(KERN_WARNING "EXT3-fs: Ignoring nobh option - "
+				"its supported only with writeback mode\n");
+			clear_opt(sbi->s_mount_opt, NOBH);
+		}
+	}
+	/*
+	 * The journal_load will have done any necessary log recovery,
+	 * so we can safely mount the rest of the filesystem now.
+	 */
+
+	root = iget(sb, EXT3_ROOT_INO);
+	sb->s_root = d_alloc_root(root);
+	if (!sb->s_root) {
+		printk(KERN_ERR "EXT3-fs: get root inode failed\n");
+		iput(root);
+		goto failed_mount4;
+	}
+	if (!S_ISDIR(root->i_mode) || !root->i_blocks || !root->i_size) {
+		dput(sb->s_root);
+		sb->s_root = NULL;
+		printk(KERN_ERR "EXT3-fs: corrupt root inode, run e2fsck\n");
+		goto failed_mount4;
+	}
+
+	ext3_setup_super (sb, es, sb->s_flags & MS_RDONLY);
+	/*
+	 * akpm: core read_super() calls in here with the superblock locked.
+	 * That deadlocks, because orphan cleanup needs to lock the superblock
+	 * in numerous places.  Here we just pop the lock - it's relatively
+	 * harmless, because we are now ready to accept write_super() requests,
+	 * and aviro says that's the only reason for hanging onto the
+	 * superblock lock.
+	 */
+	EXT3_SB(sb)->s_mount_state |= EXT3_ORPHAN_FS;
+	ext3_orphan_cleanup(sb, es);
+	EXT3_SB(sb)->s_mount_state &= ~EXT3_ORPHAN_FS;
+	if (needs_recovery)
+		printk (KERN_INFO "EXT3-fs: recovery complete.\n");
+	ext3_mark_recovery_complete(sb, es);
+	printk (KERN_INFO "EXT3-fs: mounted filesystem with %s data mode.\n",
+		test_opt(sb,DATA_FLAGS) == EXT3_MOUNT_JOURNAL_DATA ? "journal":
+		test_opt(sb,DATA_FLAGS) == EXT3_MOUNT_ORDERED_DATA ? "ordered":
+		"writeback");
+
+	lock_kernel();
+	return 0;
+
+cantfind_ext3:
+	if (!silent)
+		printk(KERN_ERR "VFS: Can't find ext3 filesystem on dev %s.\n",
+		       sb->s_id);
+	goto failed_mount;
+
+failed_mount4:
+	journal_destroy(sbi->s_journal);
+failed_mount3:
+	percpu_counter_destroy(&sbi->s_freeblocks_counter);
+	percpu_counter_destroy(&sbi->s_freeinodes_counter);
+	percpu_counter_destroy(&sbi->s_dirs_counter);
+failed_mount2:
+	for (i = 0; i < db_count; i++)
+		brelse(sbi->s_group_desc[i]);
+	kfree(sbi->s_group_desc);
+failed_mount:
+#ifdef CONFIG_QUOTA
+	for (i = 0; i < MAXQUOTAS; i++)
+		kfree(sbi->s_qf_names[i]);
+#endif
+	ext3_blkdev_remove(sbi);
+	brelse(bh);
+out_fail:
+	sb->s_fs_info = NULL;
+	kfree(sbi);
+	lock_kernel();
+	return -EINVAL;
+}
+
+/*
+ * Setup any per-fs journal parameters now.  We'll do this both on
+ * initial mount, once the journal has been initialised but before we've
+ * done any recovery; and again on any subsequent remount.
+ */
+static void ext3_init_journal_params(struct super_block *sb, journal_t *journal)
+{
+	struct ext3_sb_info *sbi = EXT3_SB(sb);
+
+	if (sbi->s_commit_interval)
+		journal->j_commit_interval = sbi->s_commit_interval;
+	/* We could also set up an ext3-specific default for the commit
+	 * interval here, but for now we'll just fall back to the jbd
+	 * default. */
+
+	spin_lock(&journal->j_state_lock);
+	if (test_opt(sb, BARRIER))
+		journal->j_flags |= JFS_BARRIER;
+	else
+		journal->j_flags &= ~JFS_BARRIER;
+	spin_unlock(&journal->j_state_lock);
+}
+
+static journal_t *ext3_get_journal(struct super_block *sb,
+				   unsigned int journal_inum)
+{
+	struct inode *journal_inode;
+	journal_t *journal;
+
+	/* First, test for the existence of a valid inode on disk.  Bad
+	 * things happen if we iget() an unused inode, as the subsequent
+	 * iput() will try to delete it. */
+
+	journal_inode = iget(sb, journal_inum);
+	if (!journal_inode) {
+		printk(KERN_ERR "EXT3-fs: no journal found.\n");
+		return NULL;
+	}
+	if (!journal_inode->i_nlink) {
+		make_bad_inode(journal_inode);
+		iput(journal_inode);
+		printk(KERN_ERR "EXT3-fs: journal inode is deleted.\n");
+		return NULL;
+	}
+
+	jbd_debug(2, "Journal inode found at %p: %Ld bytes\n",
+		  journal_inode, journal_inode->i_size);
+	if (is_bad_inode(journal_inode) || !S_ISREG(journal_inode->i_mode)) {
+		printk(KERN_ERR "EXT3-fs: invalid journal inode.\n");
+		iput(journal_inode);
+		return NULL;
+	}
+
+	journal = journal_init_inode(journal_inode);
+	if (!journal) {
+		printk(KERN_ERR "EXT3-fs: Could not load journal inode\n");
+		iput(journal_inode);
+		return NULL;
+	}
+	journal->j_private = sb;
+	ext3_init_journal_params(sb, journal);
+	return journal;
+}
+
+static journal_t *ext3_get_dev_journal(struct super_block *sb,
+				       dev_t j_dev)
+{
+	struct buffer_head * bh;
+	journal_t *journal;
+	ext3_fsblk_t start;
+	ext3_fsblk_t len;
+	int hblock, blocksize;
+	ext3_fsblk_t sb_block;
+	unsigned long offset;
+	struct ext3_super_block * es;
+	struct block_device *bdev;
+
+	bdev = ext3_blkdev_get(j_dev);
+	if (bdev == NULL)
+		return NULL;
+
+	if (bd_claim(bdev, sb)) {
+		printk(KERN_ERR
+		        "EXT3: failed to claim external journal device.\n");
+		blkdev_put(bdev);
+		return NULL;
+	}
+
+	blocksize = sb->s_blocksize;
+	hblock = bdev_hardsect_size(bdev);
+	if (blocksize < hblock) {
+		printk(KERN_ERR
+			"EXT3-fs: blocksize too small for journal device.\n");
+		goto out_bdev;
+	}
+
+	sb_block = EXT3_MIN_BLOCK_SIZE / blocksize;
+	offset = EXT3_MIN_BLOCK_SIZE % blocksize;
+	set_blocksize(bdev, blocksize);
+	if (!(bh = __bread(bdev, sb_block, blocksize))) {
+		printk(KERN_ERR "EXT3-fs: couldn't read superblock of "
+		       "external journal\n");
+		goto out_bdev;
+	}
+
+	es = (struct ext3_super_block *) (((char *)bh->b_data) + offset);
+	if ((le16_to_cpu(es->s_magic) != EXT3_SUPER_MAGIC) ||
+	    !(le32_to_cpu(es->s_feature_incompat) &
+	      EXT3_FEATURE_INCOMPAT_JOURNAL_DEV)) {
+		printk(KERN_ERR "EXT3-fs: external journal has "
+					"bad superblock\n");
+		brelse(bh);
+		goto out_bdev;
+	}
+
+	if (memcmp(EXT3_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
+		printk(KERN_ERR "EXT3-fs: journal UUID does not match\n");
+		brelse(bh);
+		goto out_bdev;
+	}
+
+	len = le32_to_cpu(es->s_blocks_count);
+	start = sb_block + 1;
+	brelse(bh);	/* we're done with the superblock */
+
+	journal = journal_init_dev(bdev, sb->s_bdev,
+					start, len, blocksize);
+	if (!journal) {
+		printk(KERN_ERR "EXT3-fs: failed to create device journal\n");
+		goto out_bdev;
+	}
+	journal->j_private = sb;
+	ll_rw_block(READ, 1, &journal->j_sb_buffer);
+	wait_on_buffer(journal->j_sb_buffer);
+	if (!buffer_uptodate(journal->j_sb_buffer)) {
+		printk(KERN_ERR "EXT3-fs: I/O error on journal device\n");
+		goto out_journal;
+	}
+	if (be32_to_cpu(journal->j_superblock->s_nr_users) != 1) {
+		printk(KERN_ERR "EXT3-fs: External journal has more than one "
+					"user (unsupported) - %d\n",
+			be32_to_cpu(journal->j_superblock->s_nr_users));
+		goto out_journal;
+	}
+	EXT3_SB(sb)->journal_bdev = bdev;
+	ext3_init_journal_params(sb, journal);
+	return journal;
+out_journal:
+	journal_destroy(journal);
+out_bdev:
+	ext3_blkdev_put(bdev);
+	return NULL;
+}
+
+static int ext3_load_journal(struct super_block *sb,
+			     struct ext3_super_block *es,
+			     unsigned long journal_devnum)
+{
+	journal_t *journal;
+	unsigned int journal_inum = le32_to_cpu(es->s_journal_inum);
+	dev_t journal_dev;
+	int err = 0;
+	int really_read_only;
+
+	if (journal_devnum &&
+	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
+		printk(KERN_INFO "EXT3-fs: external journal device major/minor "
+			"numbers have changed\n");
+		journal_dev = new_decode_dev(journal_devnum);
+	} else
+		journal_dev = new_decode_dev(le32_to_cpu(es->s_journal_dev));
+
+	really_read_only = bdev_read_only(sb->s_bdev);
+
+	/*
+	 * Are we loading a blank journal or performing recovery after a
+	 * crash?  For recovery, we need to check in advance whether we
+	 * can get read-write access to the device.
+	 */
+
+	if (EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER)) {
+		if (sb->s_flags & MS_RDONLY) {
+			printk(KERN_INFO "EXT3-fs: INFO: recovery "
+					"required on readonly filesystem.\n");
+			if (really_read_only) {
+				printk(KERN_ERR "EXT3-fs: write access "
+					"unavailable, cannot proceed.\n");
+				return -EROFS;
+			}
+			printk (KERN_INFO "EXT3-fs: write access will "
+					"be enabled during recovery.\n");
+		}
+	}
+
+	if (journal_inum && journal_dev) {
+		printk(KERN_ERR "EXT3-fs: filesystem has both journal "
+		       "and inode journals!\n");
+		return -EINVAL;
+	}
+
+	if (journal_inum) {
+		if (!(journal = ext3_get_journal(sb, journal_inum)))
+			return -EINVAL;
+	} else {
+		if (!(journal = ext3_get_dev_journal(sb, journal_dev)))
+			return -EINVAL;
+	}
+
+	if (!really_read_only && test_opt(sb, UPDATE_JOURNAL)) {
+		err = journal_update_format(journal);
+		if (err)  {
+			printk(KERN_ERR "EXT3-fs: error updating journal.\n");
+			journal_destroy(journal);
+			return err;
+		}
+	}
+
+	if (!EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER))
+		err = journal_wipe(journal, !really_read_only);
+	if (!err)
+		err = journal_load(journal);
+
+	if (err) {
+		printk(KERN_ERR "EXT3-fs: error loading journal.\n");
+		journal_destroy(journal);
+		return err;
+	}
+
+	EXT3_SB(sb)->s_journal = journal;
+	ext3_clear_journal_err(sb, es);
+
+	if (journal_devnum &&
+	    journal_devnum != le32_to_cpu(es->s_journal_dev)) {
+		es->s_journal_dev = cpu_to_le32(journal_devnum);
+		sb->s_dirt = 1;
+
+		/* Make sure we flush the recovery flag to disk. */
+		ext3_commit_super(sb, es, 1);
+	}
+
+	return 0;
+}
+
+static int ext3_create_journal(struct super_block * sb,
+			       struct ext3_super_block * es,
+			       unsigned int journal_inum)
+{
+	journal_t *journal;
+
+	if (sb->s_flags & MS_RDONLY) {
+		printk(KERN_ERR "EXT3-fs: readonly filesystem when trying to "
+				"create journal.\n");
+		return -EROFS;
+	}
+
+	if (!(journal = ext3_get_journal(sb, journal_inum)))
+		return -EINVAL;
+
+	printk(KERN_INFO "EXT3-fs: creating new journal on inode %u\n",
+	       journal_inum);
+
+	if (journal_create(journal)) {
+		printk(KERN_ERR "EXT3-fs: error creating journal.\n");
+		journal_destroy(journal);
+		return -EIO;
+	}
+
+	EXT3_SB(sb)->s_journal = journal;
+
+	ext3_update_dynamic_rev(sb);
+	EXT3_SET_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
+	EXT3_SET_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_HAS_JOURNAL);
+
+	es->s_journal_inum = cpu_to_le32(journal_inum);
+	sb->s_dirt = 1;
+
+	/* Make sure we flush the recovery flag to disk. */
+	ext3_commit_super(sb, es, 1);
+
+	return 0;
+}
+
+static void ext3_commit_super (struct super_block * sb,
+			       struct ext3_super_block * es,
+			       int sync)
+{
+	struct buffer_head *sbh = EXT3_SB(sb)->s_sbh;
+
+	if (!sbh)
+		return;
+	es->s_wtime = cpu_to_le32(get_seconds());
+	es->s_free_blocks_count = cpu_to_le32(ext3_count_free_blocks(sb));
+	es->s_free_inodes_count = cpu_to_le32(ext3_count_free_inodes(sb));
+	BUFFER_TRACE(sbh, "marking dirty");
+	mark_buffer_dirty(sbh);
+	if (sync)
+		sync_dirty_buffer(sbh);
+}
+
+
+/*
+ * Have we just finished recovery?  If so, and if we are mounting (or
+ * remounting) the filesystem readonly, then we will end up with a
+ * consistent fs on disk.  Record that fact.
+ */
+static void ext3_mark_recovery_complete(struct super_block * sb,
+					struct ext3_super_block * es)
+{
+	journal_t *journal = EXT3_SB(sb)->s_journal;
+
+	journal_lock_updates(journal);
+	journal_flush(journal);
+	if (EXT3_HAS_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER) &&
+	    sb->s_flags & MS_RDONLY) {
+		EXT3_CLEAR_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
+		sb->s_dirt = 0;
+		ext3_commit_super(sb, es, 1);
+	}
+	journal_unlock_updates(journal);
+}
+
+/*
+ * If we are mounting (or read-write remounting) a filesystem whose journal
+ * has recorded an error from a previous lifetime, move that error to the
+ * main filesystem now.
+ */
+static void ext3_clear_journal_err(struct super_block * sb,
+				   struct ext3_super_block * es)
+{
+	journal_t *journal;
+	int j_errno;
+	const char *errstr;
+
+	journal = EXT3_SB(sb)->s_journal;
+
+	/*
+	 * Now check for any error status which may have been recorded in the
+	 * journal by a prior ext3_error() or ext3_abort()
+	 */
+
+	j_errno = journal_errno(journal);
+	if (j_errno) {
+		char nbuf[16];
+
+		errstr = ext3_decode_error(sb, j_errno, nbuf);
+		ext3_warning(sb, __FUNCTION__, "Filesystem error recorded "
+			     "from previous mount: %s", errstr);
+		ext3_warning(sb, __FUNCTION__, "Marking fs in need of "
+			     "filesystem check.");
+
+		EXT3_SB(sb)->s_mount_state |= EXT3_ERROR_FS;
+		es->s_state |= cpu_to_le16(EXT3_ERROR_FS);
+		ext3_commit_super (sb, es, 1);
+
+		journal_clear_err(journal);
+	}
+}
+
+/*
+ * Force the running and committing transactions to commit,
+ * and wait on the commit.
+ */
+int ext3_force_commit(struct super_block *sb)
+{
+	journal_t *journal;
+	int ret;
+
+	if (sb->s_flags & MS_RDONLY)
+		return 0;
+
+	journal = EXT3_SB(sb)->s_journal;
+	sb->s_dirt = 0;
+	ret = ext3_journal_force_commit(journal);
+	return ret;
+}
+
+/*
+ * Ext3 always journals updates to the superblock itself, so we don't
+ * have to propagate any other updates to the superblock on disk at this
+ * point.  Just start an async writeback to get the buffers on their way
+ * to the disk.
+ *
+ * This implicitly triggers the writebehind on sync().
+ */
+
+static void ext3_write_super (struct super_block * sb)
+{
+	if (mutex_trylock(&sb->s_lock) != 0)
+		BUG();
+	sb->s_dirt = 0;
+}
+
+static int ext3_sync_fs(struct super_block *sb, int wait)
+{
+	tid_t target;
+
+	sb->s_dirt = 0;
+	if (journal_start_commit(EXT3_SB(sb)->s_journal, &target)) {
+		if (wait)
+			log_wait_commit(EXT3_SB(sb)->s_journal, target);
+	}
+	return 0;
+}
+
+/*
+ * LVM calls this function before a (read-only) snapshot is created.  This
+ * gives us a chance to flush the journal completely and mark the fs clean.
+ */
+static void ext3_write_super_lockfs(struct super_block *sb)
+{
+	sb->s_dirt = 0;
+
+	if (!(sb->s_flags & MS_RDONLY)) {
+		journal_t *journal = EXT3_SB(sb)->s_journal;
+
+		/* Now we set up the journal barrier. */
+		journal_lock_updates(journal);
+		journal_flush(journal);
+
+		/* Journal blocked and flushed, clear needs_recovery flag. */
+		EXT3_CLEAR_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
+		ext3_commit_super(sb, EXT3_SB(sb)->s_es, 1);
+	}
+}
+
+/*
+ * Called by LVM after the snapshot is done.  We need to reset the RECOVER
+ * flag here, even though the filesystem is not technically dirty yet.
+ */
+static void ext3_unlockfs(struct super_block *sb)
+{
+	if (!(sb->s_flags & MS_RDONLY)) {
+		lock_super(sb);
+		/* Reser the needs_recovery flag before the fs is unlocked. */
+		EXT3_SET_INCOMPAT_FEATURE(sb, EXT3_FEATURE_INCOMPAT_RECOVER);
+		ext3_commit_super(sb, EXT3_SB(sb)->s_es, 1);
+		unlock_super(sb);
+		journal_unlock_updates(EXT3_SB(sb)->s_journal);
+	}
+}
+
+static int ext3_remount (struct super_block * sb, int * flags, char * data)
+{
+	struct ext3_super_block * es;
+	struct ext3_sb_info *sbi = EXT3_SB(sb);
+	ext3_fsblk_t n_blocks_count = 0;
+	unsigned long old_sb_flags;
+	struct ext3_mount_options old_opts;
+	int err;
+#ifdef CONFIG_QUOTA
+	int i;
+#endif
+
+	/* Store the original options */
+	old_sb_flags = sb->s_flags;
+	old_opts.s_mount_opt = sbi->s_mount_opt;
+	old_opts.s_resuid = sbi->s_resuid;
+	old_opts.s_resgid = sbi->s_resgid;
+	old_opts.s_commit_interval = sbi->s_commit_interval;
+#ifdef CONFIG_QUOTA
+	old_opts.s_jquota_fmt = sbi->s_jquota_fmt;
+	for (i = 0; i < MAXQUOTAS; i++)
+		old_opts.s_qf_names[i] = sbi->s_qf_names[i];
+#endif
+
+	/*
+	 * Allow the "check" option to be passed as a remount option.
+	 */
+	if (!parse_options(data, sb, NULL, NULL, &n_blocks_count, 1)) {
+		err = -EINVAL;
+		goto restore_opts;
+	}
+
+	if (sbi->s_mount_opt & EXT3_MOUNT_ABORT)
+		ext3_abort(sb, __FUNCTION__, "Abort forced by user");
+
+	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
+		((sbi->s_mount_opt & EXT3_MOUNT_POSIX_ACL) ? MS_POSIXACL : 0);
+
+	es = sbi->s_es;
+
+	ext3_init_journal_params(sb, sbi->s_journal);
+
+	if ((*flags & MS_RDONLY) != (sb->s_flags & MS_RDONLY) ||
+		n_blocks_count > le32_to_cpu(es->s_blocks_count)) {
+		if (sbi->s_mount_opt & EXT3_MOUNT_ABORT) {
+			err = -EROFS;
+			goto restore_opts;
+		}
+
+		if (*flags & MS_RDONLY) {
+			/*
+			 * First of all, the unconditional stuff we have to do
+			 * to disable replay of the journal when we next remount
+			 */
+			sb->s_flags |= MS_RDONLY;
+
+			/*
+			 * OK, test if we are remounting a valid rw partition
+			 * readonly, and if so set the rdonly flag and then
+			 * mark the partition as valid again.
+			 */
+			if (!(es->s_state & cpu_to_le16(EXT3_VALID_FS)) &&
+			    (sbi->s_mount_state & EXT3_VALID_FS))
+				es->s_state = cpu_to_le16(sbi->s_mount_state);
+
+			ext3_mark_recovery_complete(sb, es);
+		} else {
+			__le32 ret;
+			if ((ret = EXT3_HAS_RO_COMPAT_FEATURE(sb,
+					~EXT3_FEATURE_RO_COMPAT_SUPP))) {
+				printk(KERN_WARNING "EXT3-fs: %s: couldn't "
+				       "remount RDWR because of unsupported "
+				       "optional features (%x).\n",
+				       sb->s_id, le32_to_cpu(ret));
+				err = -EROFS;
+				goto restore_opts;
+			}
+			/*
+			 * Mounting a RDONLY partition read-write, so reread
+			 * and store the current valid flag.  (It may have
+			 * been changed by e2fsck since we originally mounted
+			 * the partition.)
+			 */
+			ext3_clear_journal_err(sb, es);
+			sbi->s_mount_state = le16_to_cpu(es->s_state);
+			if ((err = ext3_group_extend(sb, es, n_blocks_count)))
+				goto restore_opts;
+			if (!ext3_setup_super (sb, es, 0))
+				sb->s_flags &= ~MS_RDONLY;
+		}
+	}
+#ifdef CONFIG_QUOTA
+	/* Release old quota file names */
+	for (i = 0; i < MAXQUOTAS; i++)
+		if (old_opts.s_qf_names[i] &&
+		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
+			kfree(old_opts.s_qf_names[i]);
+#endif
+	return 0;
+restore_opts:
+	sb->s_flags = old_sb_flags;
+	sbi->s_mount_opt = old_opts.s_mount_opt;
+	sbi->s_resuid = old_opts.s_resuid;
+	sbi->s_resgid = old_opts.s_resgid;
+	sbi->s_commit_interval = old_opts.s_commit_interval;
+#ifdef CONFIG_QUOTA
+	sbi->s_jquota_fmt = old_opts.s_jquota_fmt;
+	for (i = 0; i < MAXQUOTAS; i++) {
+		if (sbi->s_qf_names[i] &&
+		    old_opts.s_qf_names[i] != sbi->s_qf_names[i])
+			kfree(sbi->s_qf_names[i]);
+		sbi->s_qf_names[i] = old_opts.s_qf_names[i];
+	}
+#endif
+	return err;
+}
+
+static int ext3_statfs (struct dentry * dentry, struct kstatfs * buf)
+{
+	struct super_block *sb = dentry->d_sb;
+	struct ext3_sb_info *sbi = EXT3_SB(sb);
+	struct ext3_super_block *es = sbi->s_es;
+	ext3_fsblk_t overhead;
+	int i;
+
+	if (test_opt (sb, MINIX_DF))
+		overhead = 0;
+	else {
+		unsigned long ngroups;
+		ngroups = EXT3_SB(sb)->s_groups_count;
+		smp_rmb();
+
+		/*
+		 * Compute the overhead (FS structures)
+		 */
+
+		/*
+		 * All of the blocks before first_data_block are
+		 * overhead
+		 */
+		overhead = le32_to_cpu(es->s_first_data_block);
+
+		/*
+		 * Add the overhead attributed to the superblock and
+		 * block group descriptors.  If the sparse superblocks
+		 * feature is turned on, then not all groups have this.
+		 */
+		for (i = 0; i < ngroups; i++) {
+			overhead += ext3_bg_has_super(sb, i) +
+				ext3_bg_num_gdb(sb, i);
+			cond_resched();
+		}
+
+		/*
+		 * Every block group has an inode bitmap, a block
+		 * bitmap, and an inode table.
+		 */
+		overhead += (ngroups * (2 + EXT3_SB(sb)->s_itb_per_group));
+	}
+
+	buf->f_type = EXT3_SUPER_MAGIC;
+	buf->f_bsize = sb->s_blocksize;
+	buf->f_blocks = le32_to_cpu(es->s_blocks_count) - overhead;
+	buf->f_bfree = percpu_counter_sum(&sbi->s_freeblocks_counter);
+	buf->f_bavail = buf->f_bfree - le32_to_cpu(es->s_r_blocks_count);
+	if (buf->f_bfree < le32_to_cpu(es->s_r_blocks_count))
+		buf->f_bavail = 0;
+	buf->f_files = le32_to_cpu(es->s_inodes_count);
+	buf->f_ffree = percpu_counter_sum(&sbi->s_freeinodes_counter);
+	buf->f_namelen = EXT3_NAME_LEN;
+	return 0;
+}
+
+/* Helper function for writing quotas on sync - we need to start transaction before quota file
+ * is locked for write. Otherwise the are possible deadlocks:
+ * Process 1                         Process 2
+ * ext3_create()                     quota_sync()
+ *   journal_start()                   write_dquot()
+ *   DQUOT_INIT()                        down(dqio_mutex)
+ *     down(dqio_mutex)                    journal_start()
+ *
+ */
+
+#ifdef CONFIG_QUOTA
+
+static inline struct inode *dquot_to_inode(struct dquot *dquot)
+{
+	return sb_dqopt(dquot->dq_sb)->files[dquot->dq_type];
+}
+
+static int ext3_dquot_initialize(struct inode *inode, int type)
+{
+	handle_t *handle;
+	int ret, err;
+
+	/* We may create quota structure so we need to reserve enough blocks */
+	handle = ext3_journal_start(inode, 2*EXT3_QUOTA_INIT_BLOCKS(inode->i_sb));
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	ret = dquot_initialize(inode, type);
+	err = ext3_journal_stop(handle);
+	if (!ret)
+		ret = err;
+	return ret;
+}
+
+static int ext3_dquot_drop(struct inode *inode)
+{
+	handle_t *handle;
+	int ret, err;
+
+	/* We may delete quota structure so we need to reserve enough blocks */
+	handle = ext3_journal_start(inode, 2*EXT3_QUOTA_DEL_BLOCKS(inode->i_sb));
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	ret = dquot_drop(inode);
+	err = ext3_journal_stop(handle);
+	if (!ret)
+		ret = err;
+	return ret;
+}
+
+static int ext3_write_dquot(struct dquot *dquot)
+{
+	int ret, err;
+	handle_t *handle;
+	struct inode *inode;
+
+	inode = dquot_to_inode(dquot);
+	handle = ext3_journal_start(inode,
+					EXT3_QUOTA_TRANS_BLOCKS(dquot->dq_sb));
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	ret = dquot_commit(dquot);
+	err = ext3_journal_stop(handle);
+	if (!ret)
+		ret = err;
+	return ret;
+}
+
+static int ext3_acquire_dquot(struct dquot *dquot)
+{
+	int ret, err;
+	handle_t *handle;
+
+	handle = ext3_journal_start(dquot_to_inode(dquot),
+					EXT3_QUOTA_INIT_BLOCKS(dquot->dq_sb));
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	ret = dquot_acquire(dquot);
+	err = ext3_journal_stop(handle);
+	if (!ret)
+		ret = err;
+	return ret;
+}
+
+static int ext3_release_dquot(struct dquot *dquot)
+{
+	int ret, err;
+	handle_t *handle;
+
+	handle = ext3_journal_start(dquot_to_inode(dquot),
+					EXT3_QUOTA_DEL_BLOCKS(dquot->dq_sb));
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	ret = dquot_release(dquot);
+	err = ext3_journal_stop(handle);
+	if (!ret)
+		ret = err;
+	return ret;
+}
+
+static int ext3_mark_dquot_dirty(struct dquot *dquot)
+{
+	/* Are we journalling quotas? */
+	if (EXT3_SB(dquot->dq_sb)->s_qf_names[USRQUOTA] ||
+	    EXT3_SB(dquot->dq_sb)->s_qf_names[GRPQUOTA]) {
+		dquot_mark_dquot_dirty(dquot);
+		return ext3_write_dquot(dquot);
+	} else {
+		return dquot_mark_dquot_dirty(dquot);
+	}
+}
+
+static int ext3_write_info(struct super_block *sb, int type)
+{
+	int ret, err;
+	handle_t *handle;
+
+	/* Data block + inode block */
+	handle = ext3_journal_start(sb->s_root->d_inode, 2);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+	ret = dquot_commit_info(sb, type);
+	err = ext3_journal_stop(handle);
+	if (!ret)
+		ret = err;
+	return ret;
+}
+
+/*
+ * Turn on quotas during mount time - we need to find
+ * the quota file and such...
+ */
+static int ext3_quota_on_mount(struct super_block *sb, int type)
+{
+	return vfs_quota_on_mount(sb, EXT3_SB(sb)->s_qf_names[type],
+			EXT3_SB(sb)->s_jquota_fmt, type);
+}
+
+/*
+ * Standard function to be called on quota_on
+ */
+static int ext3_quota_on(struct super_block *sb, int type, int format_id,
+			 char *path)
+{
+	int err;
+	struct nameidata nd;
+
+	if (!test_opt(sb, QUOTA))
+		return -EINVAL;
+	/* Not journalling quota? */
+	if (!EXT3_SB(sb)->s_qf_names[USRQUOTA] &&
+	    !EXT3_SB(sb)->s_qf_names[GRPQUOTA])
+		return vfs_quota_on(sb, type, format_id, path);
+	err = path_lookup(path, LOOKUP_FOLLOW, &nd);
+	if (err)
+		return err;
+	/* Quotafile not on the same filesystem? */
+	if (nd.mnt->mnt_sb != sb) {
+		path_release(&nd);
+		return -EXDEV;
+	}
+	/* Quotafile not of fs root? */
+	if (nd.dentry->d_parent->d_inode != sb->s_root->d_inode)
+		printk(KERN_WARNING
+			"EXT3-fs: Quota file not on filesystem root. "
+			"Journalled quota will not work.\n");
+	path_release(&nd);
+	return vfs_quota_on(sb, type, format_id, path);
+}
+
+/* Read data from quotafile - avoid pagecache and such because we cannot afford
+ * acquiring the locks... As quota files are never truncated and quota code
+ * itself serializes the operations (and noone else should touch the files)
+ * we don't have to be afraid of races */
+static ssize_t ext3_quota_read(struct super_block *sb, int type, char *data,
+			       size_t len, loff_t off)
+{
+	struct inode *inode = sb_dqopt(sb)->files[type];
+	sector_t blk = off >> EXT3_BLOCK_SIZE_BITS(sb);
+	int err = 0;
+	int offset = off & (sb->s_blocksize - 1);
+	int tocopy;
+	size_t toread;
+	struct buffer_head *bh;
+	loff_t i_size = i_size_read(inode);
+
+	if (off > i_size)
+		return 0;
+	if (off+len > i_size)
+		len = i_size-off;
+	toread = len;
+	while (toread > 0) {
+		tocopy = sb->s_blocksize - offset < toread ?
+				sb->s_blocksize - offset : toread;
+		bh = ext3_bread(NULL, inode, blk, 0, &err);
+		if (err)
+			return err;
+		if (!bh)	/* A hole? */
+			memset(data, 0, tocopy);
+		else
+			memcpy(data, bh->b_data+offset, tocopy);
+		brelse(bh);
+		offset = 0;
+		toread -= tocopy;
+		data += tocopy;
+		blk++;
+	}
+	return len;
+}
+
+/* Write to quotafile (we know the transaction is already started and has
+ * enough credits) */
+static ssize_t ext3_quota_write(struct super_block *sb, int type,
+				const char *data, size_t len, loff_t off)
+{
+	struct inode *inode = sb_dqopt(sb)->files[type];
+	sector_t blk = off >> EXT3_BLOCK_SIZE_BITS(sb);
+	int err = 0;
+	int offset = off & (sb->s_blocksize - 1);
+	int tocopy;
+	int journal_quota = EXT3_SB(sb)->s_qf_names[type] != NULL;
+	size_t towrite = len;
+	struct buffer_head *bh;
+	handle_t *handle = journal_current_handle();
+
+	mutex_lock_nested(&inode->i_mutex, I_MUTEX_QUOTA);
+	while (towrite > 0) {
+		tocopy = sb->s_blocksize - offset < towrite ?
+				sb->s_blocksize - offset : towrite;
+		bh = ext3_bread(handle, inode, blk, 1, &err);
+		if (!bh)
+			goto out;
+		if (journal_quota) {
+			err = ext3_journal_get_write_access(handle, bh);
+			if (err) {
+				brelse(bh);
+				goto out;
+			}
+		}
+		lock_buffer(bh);
+		memcpy(bh->b_data+offset, data, tocopy);
+		flush_dcache_page(bh->b_page);
+		unlock_buffer(bh);
+		if (journal_quota)
+			err = ext3_journal_dirty_metadata(handle, bh);
+		else {
+			/* Always do at least ordered writes for quotas */
+			err = ext3_journal_dirty_data(handle, bh);
+			mark_buffer_dirty(bh);
+		}
+		brelse(bh);
+		if (err)
+			goto out;
+		offset = 0;
+		towrite -= tocopy;
+		data += tocopy;
+		blk++;
+	}
+out:
+	if (len == towrite)
+		return err;
+	if (inode->i_size < off+len-towrite) {
+		i_size_write(inode, off+len-towrite);
+		EXT3_I(inode)->i_disksize = inode->i_size;
+	}
+	inode->i_version++;
+	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+	ext3_mark_inode_dirty(handle, inode);
+	mutex_unlock(&inode->i_mutex);
+	return len - towrite;
+}
+
+#endif
+
+static int ext3_get_sb(struct file_system_type *fs_type,
+	int flags, const char *dev_name, void *data, struct vfsmount *mnt)
+{
+	return get_sb_bdev(fs_type, flags, dev_name, data, ext3_fill_super, mnt);
+}
+
+static struct file_system_type ext3_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "ext3",
+	.get_sb		= ext3_get_sb,
+	.kill_sb	= kill_block_super,
+	.fs_flags	= FS_REQUIRES_DEV,
+};
+
+static int __init init_ext3_fs(void)
+{
+	int err = init_ext3_xattr();
+	if (err)
+		return err;
+	err = init_inodecache();
+	if (err)
+		goto out1;
+        err = register_filesystem(&ext3_fs_type);
+	if (err)
+		goto out;
+	return 0;
+out:
+	destroy_inodecache();
+out1:
+	exit_ext3_xattr();
+	return err;
+}
+
+static void __exit exit_ext3_fs(void)
+{
+	unregister_filesystem(&ext3_fs_type);
+	destroy_inodecache();
+	exit_ext3_xattr();
+}
+
+MODULE_AUTHOR("Remy Card, Stephen Tweedie, Andrew Morton, Andreas Dilger, Theodore Ts'o and others");
+MODULE_DESCRIPTION("Second Extended Filesystem with journaling extensions");
+MODULE_LICENSE("GPL");
+module_init(init_ext3_fs)
+module_exit(exit_ext3_fs)

fs/ext4/symlink.c

+/*
+ *  linux/fs/ext3/symlink.c
+ *
+ * Only fast symlinks left here - the rest is done by generic code. AV, 1999
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/fs/minix/symlink.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ *
+ *  ext3 symlink handling code
+ */
+
+#include <linux/fs.h>
+#include <linux/jbd.h>
+#include <linux/ext3_fs.h>
+#include <linux/namei.h>
+#include "xattr.h"
+
+static void * ext3_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+	struct ext3_inode_info *ei = EXT3_I(dentry->d_inode);
+	nd_set_link(nd, (char*)ei->i_data);
+	return NULL;
+}
+
+struct inode_operations ext3_symlink_inode_operations = {
+	.readlink	= generic_readlink,
+	.follow_link	= page_follow_link_light,
+	.put_link	= page_put_link,
+#ifdef CONFIG_EXT3_FS_XATTR
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= ext3_listxattr,
+	.removexattr	= generic_removexattr,
+#endif
+};
+
+struct inode_operations ext3_fast_symlink_inode_operations = {
+	.readlink	= generic_readlink,
+	.follow_link	= ext3_follow_link,
+#ifdef CONFIG_EXT3_FS_XATTR
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
+	.listxattr	= ext3_listxattr,
+	.removexattr	= generic_removexattr,
+#endif
+};

fs/ext4/xattr.c

+/*
+ * linux/fs/ext3/xattr.c
+ *
+ * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
+ *
+ * Fix by Harrison Xing <harrison@mountainviewdata.com>.
+ * Ext3 code with a lot of help from Eric Jarman <ejarman@acm.org>.
+ * Extended attributes for symlinks and special files added per
+ *  suggestion of Luka Renko <luka.renko@hermes.si>.
+ * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
+ *  Red Hat Inc.
+ * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
+ *  and Andreas Gruenbacher <agruen@suse.de>.
+ */
+
+/*
+ * Extended attributes are stored directly in inodes (on file systems with
+ * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
+ * field contains the block number if an inode uses an additional block. All
+ * attributes must fit in the inode and one additional block. Blocks that
+ * contain the identical set of attributes may be shared among several inodes.
+ * Identical blocks are detected by keeping a cache of blocks that have
+ * recently been accessed.
+ *
+ * The attributes in inodes and on blocks have a different header; the entries
+ * are stored in the same format:
+ *
+ *   +------------------+
+ *   | header           |
+ *   | entry 1          | |
+ *   | entry 2          | | growing downwards
+ *   | entry 3          | v
+ *   | four null bytes  |
+ *   | . . .            |
+ *   | value 1          | ^
+ *   | value 3          | | growing upwards
+ *   | value 2          | |
+ *   +------------------+
+ *
+ * The header is followed by multiple entry descriptors. In disk blocks, the
+ * entry descriptors are kept sorted. In inodes, they are unsorted. The
+ * attribute values are aligned to the end of the block in no specific order.
+ *
+ * Locking strategy
+ * ----------------
+ * EXT3_I(inode)->i_file_acl is protected by EXT3_I(inode)->xattr_sem.
+ * EA blocks are only changed if they are exclusive to an inode, so
+ * holding xattr_sem also means that nothing but the EA block's reference
+ * count can change. Multiple writers to the same block are synchronized
+ * by the buffer lock.
+ */
+
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/ext3_jbd.h>
+#include <linux/ext3_fs.h>
+#include <linux/mbcache.h>
+#include <linux/quotaops.h>
+#include <linux/rwsem.h>
+#include "xattr.h"
+#include "acl.h"
+
+#define BHDR(bh) ((struct ext3_xattr_header *)((bh)->b_data))
+#define ENTRY(ptr) ((struct ext3_xattr_entry *)(ptr))
+#define BFIRST(bh) ENTRY(BHDR(bh)+1)
+#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
+
+#define IHDR(inode, raw_inode) \
+	((struct ext3_xattr_ibody_header *) \
+		((void *)raw_inode + \
+		 EXT3_GOOD_OLD_INODE_SIZE + \
+		 EXT3_I(inode)->i_extra_isize))
+#define IFIRST(hdr) ((struct ext3_xattr_entry *)((hdr)+1))
+
+#ifdef EXT3_XATTR_DEBUG
+# define ea_idebug(inode, f...) do { \
+		printk(KERN_DEBUG "inode %s:%lu: ", \
+			inode->i_sb->s_id, inode->i_ino); \
+		printk(f); \
+		printk("\n"); \
+	} while (0)
+# define ea_bdebug(bh, f...) do { \
+		char b[BDEVNAME_SIZE]; \
+		printk(KERN_DEBUG "block %s:%lu: ", \
+			bdevname(bh->b_bdev, b), \
+			(unsigned long) bh->b_blocknr); \
+		printk(f); \
+		printk("\n"); \
+	} while (0)
+#else
+# define ea_idebug(f...)
+# define ea_bdebug(f...)
+#endif
+
+static void ext3_xattr_cache_insert(struct buffer_head *);
+static struct buffer_head *ext3_xattr_cache_find(struct inode *,
+						 struct ext3_xattr_header *,
+						 struct mb_cache_entry **);
+static void ext3_xattr_rehash(struct ext3_xattr_header *,
+			      struct ext3_xattr_entry *);
+
+static struct mb_cache *ext3_xattr_cache;
+
+static struct xattr_handler *ext3_xattr_handler_map[] = {
+	[EXT3_XATTR_INDEX_USER]		     = &ext3_xattr_user_handler,
+#ifdef CONFIG_EXT3_FS_POSIX_ACL
+	[EXT3_XATTR_INDEX_POSIX_ACL_ACCESS]  = &ext3_xattr_acl_access_handler,
+	[EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext3_xattr_acl_default_handler,
+#endif
+	[EXT3_XATTR_INDEX_TRUSTED]	     = &ext3_xattr_trusted_handler,
+#ifdef CONFIG_EXT3_FS_SECURITY
+	[EXT3_XATTR_INDEX_SECURITY]	     = &ext3_xattr_security_handler,
+#endif
+};
+
+struct xattr_handler *ext3_xattr_handlers[] = {
+	&ext3_xattr_user_handler,
+	&ext3_xattr_trusted_handler,
+#ifdef CONFIG_EXT3_FS_POSIX_ACL
+	&ext3_xattr_acl_access_handler,
+	&ext3_xattr_acl_default_handler,
+#endif
+#ifdef CONFIG_EXT3_FS_SECURITY
+	&ext3_xattr_security_handler,
+#endif
+	NULL
+};
+
+static inline struct xattr_handler *
+ext3_xattr_handler(int name_index)
+{
+	struct xattr_handler *handler = NULL;
+
+	if (name_index > 0 && name_index < ARRAY_SIZE(ext3_xattr_handler_map))
+		handler = ext3_xattr_handler_map[name_index];
+	return handler;
+}
+
+/*
+ * Inode operation listxattr()
+ *
+ * dentry->d_inode->i_mutex: don't care
+ */
+ssize_t
+ext3_listxattr(struct dentry *dentry, char *buffer, size_t size)
+{
+	return ext3_xattr_list(dentry->d_inode, buffer, size);
+}
+
+static int
+ext3_xattr_check_names(struct ext3_xattr_entry *entry, void *end)
+{
+	while (!IS_LAST_ENTRY(entry)) {
+		struct ext3_xattr_entry *next = EXT3_XATTR_NEXT(entry);
+		if ((void *)next >= end)
+			return -EIO;
+		entry = next;
+	}
+	return 0;
+}
+
+static inline int
+ext3_xattr_check_block(struct buffer_head *bh)
+{
+	int error;
+
+	if (BHDR(bh)->h_magic != cpu_to_le32(EXT3_XATTR_MAGIC) ||
+	    BHDR(bh)->h_blocks != cpu_to_le32(1))
+		return -EIO;
+	error = ext3_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
+	return error;
+}
+
+static inline int
+ext3_xattr_check_entry(struct ext3_xattr_entry *entry, size_t size)
+{
+	size_t value_size = le32_to_cpu(entry->e_value_size);
+
+	if (entry->e_value_block != 0 || value_size > size ||
+	    le16_to_cpu(entry->e_value_offs) + value_size > size)
+		return -EIO;
+	return 0;
+}
+
+static int
+ext3_xattr_find_entry(struct ext3_xattr_entry **pentry, int name_index,
+		      const char *name, size_t size, int sorted)
+{
+	struct ext3_xattr_entry *entry;
+	size_t name_len;
+	int cmp = 1;
+
+	if (name == NULL)
+		return -EINVAL;
+	name_len = strlen(name);
+	entry = *pentry;
+	for (; !IS_LAST_ENTRY(entry); entry = EXT3_XATTR_NEXT(entry)) {
+		cmp = name_index - entry->e_name_index;
+		if (!cmp)
+			cmp = name_len - entry->e_name_len;
+		if (!cmp)
+			cmp = memcmp(name, entry->e_name, name_len);
+		if (cmp <= 0 && (sorted || cmp == 0))
+			break;
+	}
+	*pentry = entry;
+	if (!cmp && ext3_xattr_check_entry(entry, size))
+			return -EIO;
+	return cmp ? -ENODATA : 0;
+}
+
+static int
+ext3_xattr_block_get(struct inode *inode, int name_index, const char *name,
+		     void *buffer, size_t buffer_size)
+{
+	struct buffer_head *bh = NULL;
+	struct ext3_xattr_entry *entry;
+	size_t size;
+	int error;
+
+	ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
+		  name_index, name, buffer, (long)buffer_size);
+
+	error = -ENODATA;
+	if (!EXT3_I(inode)->i_file_acl)
+		goto cleanup;
+	ea_idebug(inode, "reading block %u", EXT3_I(inode)->i_file_acl);
+	bh = sb_bread(inode->i_sb, EXT3_I(inode)->i_file_acl);
+	if (!bh)
+		goto cleanup;
+	ea_bdebug(bh, "b_count=%d, refcount=%d",
+		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
+	if (ext3_xattr_check_block(bh)) {
+bad_block:	ext3_error(inode->i_sb, __FUNCTION__,
+			   "inode %lu: bad block "E3FSBLK, inode->i_ino,
+			   EXT3_I(inode)->i_file_acl);
+		error = -EIO;
+		goto cleanup;
+	}
+	ext3_xattr_cache_insert(bh);
+	entry = BFIRST(bh);
+	error = ext3_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
+	if (error == -EIO)
+		goto bad_block;
+	if (error)
+		goto cleanup;
+	size = le32_to_cpu(entry->e_value_size);
+	if (buffer) {
+		error = -ERANGE;
+		if (size > buffer_size)
+			goto cleanup;
+		memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
+		       size);
+	}
+	error = size;
+
+cleanup:
+	brelse(bh);
+	return error;
+}
+
+static int
+ext3_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
+		     void *buffer, size_t buffer_size)
+{
+	struct ext3_xattr_ibody_header *header;
+	struct ext3_xattr_entry *entry;
+	struct ext3_inode *raw_inode;
+	struct ext3_iloc iloc;
+	size_t size;
+	void *end;
+	int error;
+
+	if (!(EXT3_I(inode)->i_state & EXT3_STATE_XATTR))
+		return -ENODATA;
+	error = ext3_get_inode_loc(inode, &iloc);
+	if (error)
+		return error;
+	raw_inode = ext3_raw_inode(&iloc);
+	header = IHDR(inode, raw_inode);
+	entry = IFIRST(header);
+	end = (void *)raw_inode + EXT3_SB(inode->i_sb)->s_inode_size;
+	error = ext3_xattr_check_names(entry, end);
+	if (error)
+		goto cleanup;
+	error = ext3_xattr_find_entry(&entry, name_index, name,
+				      end - (void *)entry, 0);
+	if (error)
+		goto cleanup;
+	size = le32_to_cpu(entry->e_value_size);
+	if (buffer) {
+		error = -ERANGE;
+		if (size > buffer_size)
+			goto cleanup;
+		memcpy(buffer, (void *)IFIRST(header) +
+		       le16_to_cpu(entry->e_value_offs), size);
+	}
+	error = size;
+
+cleanup:
+	brelse(iloc.bh);
+	return error;
+}
+
+/*
+ * ext3_xattr_get()
+ *
+ * Copy an extended attribute into the buffer
+ * provided, or compute the buffer size required.
+ * Buffer is NULL to compute the size of the buffer required.
+ *
+ * Returns a negative error number on failure, or the number of bytes
+ * used / required on success.
+ */
+int
+ext3_xattr_get(struct inode *inode, int name_index, const char *name,
+	       void *buffer, size_t buffer_size)
+{
+	int error;
+
+	down_read(&EXT3_I(inode)->xattr_sem);
+	error = ext3_xattr_ibody_get(inode, name_index, name, buffer,
+				     buffer_size);
+	if (error == -ENODATA)
+		error = ext3_xattr_block_get(inode, name_index, name, buffer,
+					     buffer_size);
+	up_read(&EXT3_I(inode)->xattr_sem);
+	return error;
+}
+
+static int
+ext3_xattr_list_entries(struct inode *inode, struct ext3_xattr_entry *entry,
+			char *buffer, size_t buffer_size)
+{
+	size_t rest = buffer_size;
+
+	for (; !IS_LAST_ENTRY(entry); entry = EXT3_XATTR_NEXT(entry)) {
+		struct xattr_handler *handler =
+			ext3_xattr_handler(entry->e_name_index);
+
+		if (handler) {
+			size_t size = handler->list(inode, buffer, rest,
+						    entry->e_name,
+						    entry->e_name_len);
+			if (buffer) {
+				if (size > rest)
+					return -ERANGE;
+				buffer += size;
+			}
+			rest -= size;
+		}
+	}
+	return buffer_size - rest;
+}
+
+static int
+ext3_xattr_block_list(struct inode *inode, char *buffer, size_t buffer_size)
+{
+	struct buffer_head *bh = NULL;
+	int error;
+
+	ea_idebug(inode, "buffer=%p, buffer_size=%ld",
+		  buffer, (long)buffer_size);
+
+	error = 0;
+	if (!EXT3_I(inode)->i_file_acl)
+		goto cleanup;
+	ea_idebug(inode, "reading block %u", EXT3_I(inode)->i_file_acl);
+	bh = sb_bread(inode->i_sb, EXT3_I(inode)->i_file_acl);
+	error = -EIO;
+	if (!bh)
+		goto cleanup;
+	ea_bdebug(bh, "b_count=%d, refcount=%d",
+		atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
+	if (ext3_xattr_check_block(bh)) {
+		ext3_error(inode->i_sb, __FUNCTION__,
+			   "inode %lu: bad block "E3FSBLK, inode->i_ino,
+			   EXT3_I(inode)->i_file_acl);
+		error = -EIO;
+		goto cleanup;
+	}
+	ext3_xattr_cache_insert(bh);
+	error = ext3_xattr_list_entries(inode, BFIRST(bh), buffer, buffer_size);
+
+cleanup:
+	brelse(bh);
+
+	return error;
+}
+
+static int
+ext3_xattr_ibody_list(struct inode *inode, char *buffer, size_t buffer_size)
+{
+	struct ext3_xattr_ibody_header *header;
+	struct ext3_inode *raw_inode;
+	struct ext3_iloc iloc;
+	void *end;
+	int error;
+
+	if (!(EXT3_I(inode)->i_state & EXT3_STATE_XATTR))
+		return 0;
+	error = ext3_get_inode_loc(inode, &iloc);
+	if (error)
+		return error;
+	raw_inode = ext3_raw_inode(&iloc);
+	header = IHDR(inode, raw_inode);
+	end = (void *)raw_inode + EXT3_SB(inode->i_sb)->s_inode_size;
+	error = ext3_xattr_check_names(IFIRST(header), end);
+	if (error)
+		goto cleanup;
+	error = ext3_xattr_list_entries(inode, IFIRST(header),
+					buffer, buffer_size);
+
+cleanup:
+	brelse(iloc.bh);
+	return error;
+}
+
+/*
+ * ext3_xattr_list()
+ *
+ * Copy a list of attribute names into the buffer
+ * provided, or compute the buffer size required.
+ * Buffer is NULL to compute the size of the buffer required.
+ *
+ * Returns a negative error number on failure, or the number of bytes
+ * used / required on success.
+ */
+int
+ext3_xattr_list(struct inode *inode, char *buffer, size_t buffer_size)
+{
+	int i_error, b_error;
+
+	down_read(&EXT3_I(inode)->xattr_sem);
+	i_error = ext3_xattr_ibody_list(inode, buffer, buffer_size);
+	if (i_error < 0) {
+		b_error = 0;
+	} else {
+		if (buffer) {
+			buffer += i_error;
+			buffer_size -= i_error;
+		}
+		b_error = ext3_xattr_block_list(inode, buffer, buffer_size);
+		if (b_error < 0)
+			i_error = 0;
+	}
+	up_read(&EXT3_I(inode)->xattr_sem);
+	return i_error + b_error;
+}
+
+/*
+ * If the EXT3_FEATURE_COMPAT_EXT_ATTR feature of this file system is
+ * not set, set it.
+ */
+static void ext3_xattr_update_super_block(handle_t *handle,
+					  struct super_block *sb)
+{
+	if (EXT3_HAS_COMPAT_FEATURE(sb, EXT3_FEATURE_COMPAT_EXT_ATTR))
+		return;
+
+	lock_super(sb);
+	if (ext3_journal_get_write_access(handle, EXT3_SB(sb)->s_sbh) == 0) {
+		EXT3_SB(sb)->s_es->s_feature_compat |=
+			cpu_to_le32(EXT3_FEATURE_COMPAT_EXT_ATTR);
+		sb->s_dirt = 1;
+		ext3_journal_dirty_metadata(handle, EXT3_SB(sb)->s_sbh);
+	}
+	unlock_super(sb);
+}
+
+/*
+ * Release the xattr block BH: If the reference count is > 1, decrement
+ * it; otherwise free the block.
+ */
+static void
+ext3_xattr_release_block(handle_t *handle, struct inode *inode,
+			 struct buffer_head *bh)
+{
+	struct mb_cache_entry *ce = NULL;
+
+	ce = mb_cache_entry_get(ext3_xattr_cache, bh->b_bdev, bh->b_blocknr);
+	if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
+		ea_bdebug(bh, "refcount now=0; freeing");
+		if (ce)
+			mb_cache_entry_free(ce);
+		ext3_free_blocks(handle, inode, bh->b_blocknr, 1);
+		get_bh(bh);
+		ext3_forget(handle, 1, inode, bh, bh->b_blocknr);
+	} else {
+		if (ext3_journal_get_write_access(handle, bh) == 0) {
+			lock_buffer(bh);
+			BHDR(bh)->h_refcount = cpu_to_le32(
+				le32_to_cpu(BHDR(bh)->h_refcount) - 1);
+			ext3_journal_dirty_metadata(handle, bh);
+			if (IS_SYNC(inode))
+				handle->h_sync = 1;
+			DQUOT_FREE_BLOCK(inode, 1);
+			unlock_buffer(bh);
+			ea_bdebug(bh, "refcount now=%d; releasing",
+				  le32_to_cpu(BHDR(bh)->h_refcount));
+		}
+		if (ce)
+			mb_cache_entry_release(ce);
+	}
+}
+
+struct ext3_xattr_info {
+	int name_index;
+	const char *name;
+	const void *value;
+	size_t value_len;
+};
+
+struct ext3_xattr_search {
+	struct ext3_xattr_entry *first;
+	void *base;
+	void *end;
+	struct ext3_xattr_entry *here;
+	int not_found;
+};
+
+static int
+ext3_xattr_set_entry(struct ext3_xattr_info *i, struct ext3_xattr_search *s)
+{
+	struct ext3_xattr_entry *last;
+	size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
+
+	/* Compute min_offs and last. */
+	last = s->first;
+	for (; !IS_LAST_ENTRY(last); last = EXT3_XATTR_NEXT(last)) {
+		if (!last->e_value_block && last->e_value_size) {
+			size_t offs = le16_to_cpu(last->e_value_offs);
+			if (offs < min_offs)
+				min_offs = offs;
+		}
+	}
+	free = min_offs - ((void *)last - s->base) - sizeof(__u32);
+	if (!s->not_found) {
+		if (!s->here->e_value_block && s->here->e_value_size) {
+			size_t size = le32_to_cpu(s->here->e_value_size);
+			free += EXT3_XATTR_SIZE(size);
+		}
+		free += EXT3_XATTR_LEN(name_len);
+	}
+	if (i->value) {
+		if (free < EXT3_XATTR_SIZE(i->value_len) ||
+		    free < EXT3_XATTR_LEN(name_len) +
+			   EXT3_XATTR_SIZE(i->value_len))
+			return -ENOSPC;
+	}
+
+	if (i->value && s->not_found) {
+		/* Insert the new name. */
+		size_t size = EXT3_XATTR_LEN(name_len);
+		size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
+		memmove((void *)s->here + size, s->here, rest);
+		memset(s->here, 0, size);
+		s->here->e_name_index = i->name_index;
+		s->here->e_name_len = name_len;
+		memcpy(s->here->e_name, i->name, name_len);
+	} else {
+		if (!s->here->e_value_block && s->here->e_value_size) {
+			void *first_val = s->base + min_offs;
+			size_t offs = le16_to_cpu(s->here->e_value_offs);
+			void *val = s->base + offs;
+			size_t size = EXT3_XATTR_SIZE(
+				le32_to_cpu(s->here->e_value_size));
+
+			if (i->value && size == EXT3_XATTR_SIZE(i->value_len)) {
+				/* The old and the new value have the same
+				   size. Just replace. */
+				s->here->e_value_size =
+					cpu_to_le32(i->value_len);
+				memset(val + size - EXT3_XATTR_PAD, 0,
+				       EXT3_XATTR_PAD); /* Clear pad bytes. */
+				memcpy(val, i->value, i->value_len);
+				return 0;
+			}
+
+			/* Remove the old value. */
+			memmove(first_val + size, first_val, val - first_val);
+			memset(first_val, 0, size);
+			s->here->e_value_size = 0;
+			s->here->e_value_offs = 0;
+			min_offs += size;
+
+			/* Adjust all value offsets. */
+			last = s->first;
+			while (!IS_LAST_ENTRY(last)) {
+				size_t o = le16_to_cpu(last->e_value_offs);
+				if (!last->e_value_block &&
+				    last->e_value_size && o < offs)
+					last->e_value_offs =
+						cpu_to_le16(o + size);
+				last = EXT3_XATTR_NEXT(last);
+			}
+		}
+		if (!i->value) {
+			/* Remove the old name. */
+			size_t size = EXT3_XATTR_LEN(name_len);
+			last = ENTRY((void *)last - size);
+			memmove(s->here, (void *)s->here + size,
+				(void *)last - (void *)s->here + sizeof(__u32));
+			memset(last, 0, size);
+		}
+	}
+
+	if (i->value) {
+		/* Insert the new value. */
+		s->here->e_value_size = cpu_to_le32(i->value_len);
+		if (i->value_len) {
+			size_t size = EXT3_XATTR_SIZE(i->value_len);
+			void *val = s->base + min_offs - size;
+			s->here->e_value_offs = cpu_to_le16(min_offs - size);
+			memset(val + size - EXT3_XATTR_PAD, 0,
+			       EXT3_XATTR_PAD); /* Clear the pad bytes. */
+			memcpy(val, i->value, i->value_len);
+		}
+	}
+	return 0;
+}
+
+struct ext3_xattr_block_find {
+	struct ext3_xattr_search s;
+	struct buffer_head *bh;
+};
+
+static int
+ext3_xattr_block_find(struct inode *inode, struct ext3_xattr_info *i,
+		      struct ext3_xattr_block_find *bs)
+{
+	struct super_block *sb = inode->i_sb;
+	int error;
+
+	ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
+		  i->name_index, i->name, i->value, (long)i->value_len);
+
+	if (EXT3_I(inode)->i_file_acl) {
+		/* The inode already has an extended attribute block. */
+		bs->bh = sb_bread(sb, EXT3_I(inode)->i_file_acl);
+		error = -EIO;
+		if (!bs->bh)
+			goto cleanup;
+		ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
+			atomic_read(&(bs->bh->b_count)),
+			le32_to_cpu(BHDR(bs->bh)->h_refcount));
+		if (ext3_xattr_check_block(bs->bh)) {
+			ext3_error(sb, __FUNCTION__,
+				"inode %lu: bad block "E3FSBLK, inode->i_ino,
+				EXT3_I(inode)->i_file_acl);
+			error = -EIO;
+			goto cleanup;
+		}
+		/* Find the named attribute. */
+		bs->s.base = BHDR(bs->bh);
+		bs->s.first = BFIRST(bs->bh);
+		bs->s.end = bs->bh->b_data + bs->bh->b_size;
+		bs->s.here = bs->s.first;
+		error = ext3_xattr_find_entry(&bs->s.here, i->name_index,
+					      i->name, bs->bh->b_size, 1);
+		if (error && error != -ENODATA)
+			goto cleanup;
+		bs->s.not_found = error;
+	}
+	error = 0;
+
+cleanup:
+	return error;
+}
+
+static int
+ext3_xattr_block_set(handle_t *handle, struct inode *inode,
+		     struct ext3_xattr_info *i,
+		     struct ext3_xattr_block_find *bs)
+{
+	struct super_block *sb = inode->i_sb;
+	struct buffer_head *new_bh = NULL;
+	struct ext3_xattr_search *s = &bs->s;
+	struct mb_cache_entry *ce = NULL;
+	int error;
+
+#define header(x) ((struct ext3_xattr_header *)(x))
+
+	if (i->value && i->value_len > sb->s_blocksize)
+		return -ENOSPC;
+	if (s->base) {
+		ce = mb_cache_entry_get(ext3_xattr_cache, bs->bh->b_bdev,
+					bs->bh->b_blocknr);
+		if (header(s->base)->h_refcount == cpu_to_le32(1)) {
+			if (ce) {
+				mb_cache_entry_free(ce);
+				ce = NULL;
+			}
+			ea_bdebug(bs->bh, "modifying in-place");
+			error = ext3_journal_get_write_access(handle, bs->bh);
+			if (error)
+				goto cleanup;
+			lock_buffer(bs->bh);
+			error = ext3_xattr_set_entry(i, s);
+			if (!error) {
+				if (!IS_LAST_ENTRY(s->first))
+					ext3_xattr_rehash(header(s->base),
+							  s->here);
+				ext3_xattr_cache_insert(bs->bh);
+			}
+			unlock_buffer(bs->bh);
+			if (error == -EIO)
+				goto bad_block;
+			if (!error)
+				error = ext3_journal_dirty_metadata(handle,
+								    bs->bh);
+			if (error)
+				goto cleanup;
+			goto inserted;
+		} else {
+			int offset = (char *)s->here - bs->bh->b_data;
+
+			if (ce) {
+				mb_cache_entry_release(ce);
+				ce = NULL;
+			}
+			ea_bdebug(bs->bh, "cloning");
+			s->base = kmalloc(bs->bh->b_size, GFP_KERNEL);
+			error = -ENOMEM;
+			if (s->base == NULL)
+				goto cleanup;
+			memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
+			s->first = ENTRY(header(s->base)+1);
+			header(s->base)->h_refcount = cpu_to_le32(1);
+			s->here = ENTRY(s->base + offset);
+			s->end = s->base + bs->bh->b_size;
+		}
+	} else {
+		/* Allocate a buffer where we construct the new block. */
+		s->base = kmalloc(sb->s_blocksize, GFP_KERNEL);
+		/* assert(header == s->base) */
+		error = -ENOMEM;
+		if (s->base == NULL)
+			goto cleanup;
+		memset(s->base, 0, sb->s_blocksize);
+		header(s->base)->h_magic = cpu_to_le32(EXT3_XATTR_MAGIC);
+		header(s->base)->h_blocks = cpu_to_le32(1);
+		header(s->base)->h_refcount = cpu_to_le32(1);
+		s->first = ENTRY(header(s->base)+1);
+		s->here = ENTRY(header(s->base)+1);
+		s->end = s->base + sb->s_blocksize;
+	}
+
+	error = ext3_xattr_set_entry(i, s);
+	if (error == -EIO)
+		goto bad_block;
+	if (error)
+		goto cleanup;
+	if (!IS_LAST_ENTRY(s->first))
+		ext3_xattr_rehash(header(s->base), s->here);
+
+inserted:
+	if (!IS_LAST_ENTRY(s->first)) {
+		new_bh = ext3_xattr_cache_find(inode, header(s->base), &ce);
+		if (new_bh) {
+			/* We found an identical block in the cache. */
+			if (new_bh == bs->bh)
+				ea_bdebug(new_bh, "keeping");
+			else {
+				/* The old block is released after updating
+				   the inode. */
+				error = -EDQUOT;
+				if (DQUOT_ALLOC_BLOCK(inode, 1))
+					goto cleanup;
+				error = ext3_journal_get_write_access(handle,
+								      new_bh);
+				if (error)
+					goto cleanup_dquot;
+				lock_buffer(new_bh);
+				BHDR(new_bh)->h_refcount = cpu_to_le32(1 +
+					le32_to_cpu(BHDR(new_bh)->h_refcount));
+				ea_bdebug(new_bh, "reusing; refcount now=%d",
+					le32_to_cpu(BHDR(new_bh)->h_refcount));
+				unlock_buffer(new_bh);
+				error = ext3_journal_dirty_metadata(handle,
+								    new_bh);
+				if (error)
+					goto cleanup_dquot;
+			}
+			mb_cache_entry_release(ce);
+			ce = NULL;
+		} else if (bs->bh && s->base == bs->bh->b_data) {
+			/* We were modifying this block in-place. */
+			ea_bdebug(bs->bh, "keeping this block");
+			new_bh = bs->bh;
+			get_bh(new_bh);
+		} else {
+			/* We need to allocate a new block */
+			ext3_fsblk_t goal = le32_to_cpu(
+					EXT3_SB(sb)->s_es->s_first_data_block) +
+				(ext3_fsblk_t)EXT3_I(inode)->i_block_group *
+				EXT3_BLOCKS_PER_GROUP(sb);
+			ext3_fsblk_t block = ext3_new_block(handle, inode,
+							goal, &error);
+			if (error)
+				goto cleanup;
+			ea_idebug(inode, "creating block %d", block);
+
+			new_bh = sb_getblk(sb, block);
+			if (!new_bh) {
+getblk_failed:
+				ext3_free_blocks(handle, inode, block, 1);
+				error = -EIO;
+				goto cleanup;
+			}
+			lock_buffer(new_bh);
+			error = ext3_journal_get_create_access(handle, new_bh);
+			if (error) {
+				unlock_buffer(new_bh);
+				goto getblk_failed;
+			}
+			memcpy(new_bh->b_data, s->base, new_bh->b_size);
+			set_buffer_uptodate(new_bh);
+			unlock_buffer(new_bh);
+			ext3_xattr_cache_insert(new_bh);
+			error = ext3_journal_dirty_metadata(handle, new_bh);
+			if (error)
+				goto cleanup;
+		}
+	}
+
+	/* Update the inode. */
+	EXT3_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
+
+	/* Drop the previous xattr block. */
+	if (bs->bh && bs->bh != new_bh)
+		ext3_xattr_release_block(handle, inode, bs->bh);
+	error = 0;
+
+cleanup:
+	if (ce)
+		mb_cache_entry_release(ce);
+	brelse(new_bh);
+	if (!(bs->bh && s->base == bs->bh->b_data))
+		kfree(s->base);
+
+	return error;
+
+cleanup_dquot:
+	DQUOT_FREE_BLOCK(inode, 1);
+	goto cleanup;
+
+bad_block:
+	ext3_error(inode->i_sb, __FUNCTION__,
+		   "inode %lu: bad block "E3FSBLK, inode->i_ino,
+		   EXT3_I(inode)->i_file_acl);
+	goto cleanup;
+
+#undef header
+}
+
+struct ext3_xattr_ibody_find {
+	struct ext3_xattr_search s;
+	struct ext3_iloc iloc;
+};
+
+static int
+ext3_xattr_ibody_find(struct inode *inode, struct ext3_xattr_info *i,
+		      struct ext3_xattr_ibody_find *is)
+{
+	struct ext3_xattr_ibody_header *header;
+	struct ext3_inode *raw_inode;
+	int error;
+
+	if (EXT3_I(inode)->i_extra_isize == 0)
+		return 0;
+	raw_inode = ext3_raw_inode(&is->iloc);
+	header = IHDR(inode, raw_inode);
+	is->s.base = is->s.first = IFIRST(header);
+	is->s.here = is->s.first;
+	is->s.end = (void *)raw_inode + EXT3_SB(inode->i_sb)->s_inode_size;
+	if (EXT3_I(inode)->i_state & EXT3_STATE_XATTR) {
+		error = ext3_xattr_check_names(IFIRST(header), is->s.end);
+		if (error)
+			return error;
+		/* Find the named attribute. */
+		error = ext3_xattr_find_entry(&is->s.here, i->name_index,
+					      i->name, is->s.end -
+					      (void *)is->s.base, 0);
+		if (error && error != -ENODATA)
+			return error;
+		is->s.not_found = error;
+	}
+	return 0;
+}
+
+static int
+ext3_xattr_ibody_set(handle_t *handle, struct inode *inode,
+		     struct ext3_xattr_info *i,
+		     struct ext3_xattr_ibody_find *is)
+{
+	struct ext3_xattr_ibody_header *header;
+	struct ext3_xattr_search *s = &is->s;
+	int error;
+
+	if (EXT3_I(inode)->i_extra_isize == 0)
+		return -ENOSPC;
+	error = ext3_xattr_set_entry(i, s);
+	if (error)
+		return error;
+	header = IHDR(inode, ext3_raw_inode(&is->iloc));
+	if (!IS_LAST_ENTRY(s->first)) {
+		header->h_magic = cpu_to_le32(EXT3_XATTR_MAGIC);
+		EXT3_I(inode)->i_state |= EXT3_STATE_XATTR;
+	} else {
+		header->h_magic = cpu_to_le32(0);
+		EXT3_I(inode)->i_state &= ~EXT3_STATE_XATTR;
+	}
+	return 0;
+}
+
+/*
+ * ext3_xattr_set_handle()
+ *
+ * Create, replace or remove an extended attribute for this inode. Buffer
+ * is NULL to remove an existing extended attribute, and non-NULL to
+ * either replace an existing extended attribute, or create a new extended
+ * attribute. The flags XATTR_REPLACE and XATTR_CREATE
+ * specify that an extended attribute must exist and must not exist
+ * previous to the call, respectively.
+ *
+ * Returns 0, or a negative error number on failure.
+ */
+int
+ext3_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
+		      const char *name, const void *value, size_t value_len,
+		      int flags)
+{
+	struct ext3_xattr_info i = {
+		.name_index = name_index,
+		.name = name,
+		.value = value,
+		.value_len = value_len,
+
+	};
+	struct ext3_xattr_ibody_find is = {
+		.s = { .not_found = -ENODATA, },
+	};
+	struct ext3_xattr_block_find bs = {
+		.s = { .not_found = -ENODATA, },
+	};
+	int error;
+
+	if (!name)
+		return -EINVAL;
+	if (strlen(name) > 255)
+		return -ERANGE;
+	down_write(&EXT3_I(inode)->xattr_sem);
+	error = ext3_get_inode_loc(inode, &is.iloc);
+	if (error)
+		goto cleanup;
+
+	if (EXT3_I(inode)->i_state & EXT3_STATE_NEW) {
+		struct ext3_inode *raw_inode = ext3_raw_inode(&is.iloc);
+		memset(raw_inode, 0, EXT3_SB(inode->i_sb)->s_inode_size);
+		EXT3_I(inode)->i_state &= ~EXT3_STATE_NEW;
+	}
+
+	error = ext3_xattr_ibody_find(inode, &i, &is);
+	if (error)
+		goto cleanup;
+	if (is.s.not_found)
+		error = ext3_xattr_block_find(inode, &i, &bs);
+	if (error)
+		goto cleanup;
+	if (is.s.not_found && bs.s.not_found) {
+		error = -ENODATA;
+		if (flags & XATTR_REPLACE)
+			goto cleanup;
+		error = 0;
+		if (!value)
+			goto cleanup;
+	} else {
+		error = -EEXIST;
+		if (flags & XATTR_CREATE)
+			goto cleanup;
+	}
+	error = ext3_journal_get_write_access(handle, is.iloc.bh);
+	if (error)
+		goto cleanup;
+	if (!value) {
+		if (!is.s.not_found)
+			error = ext3_xattr_ibody_set(handle, inode, &i, &is);
+		else if (!bs.s.not_found)
+			error = ext3_xattr_block_set(handle, inode, &i, &bs);
+	} else {
+		error = ext3_xattr_ibody_set(handle, inode, &i, &is);
+		if (!error && !bs.s.not_found) {
+			i.value = NULL;
+			error = ext3_xattr_block_set(handle, inode, &i, &bs);
+		} else if (error == -ENOSPC) {
+			error = ext3_xattr_block_set(handle, inode, &i, &bs);
+			if (error)
+				goto cleanup;
+			if (!is.s.not_found) {
+				i.value = NULL;
+				error = ext3_xattr_ibody_set(handle, inode, &i,
+							     &is);
+			}
+		}
+	}
+	if (!error) {
+		ext3_xattr_update_super_block(handle, inode->i_sb);
+		inode->i_ctime = CURRENT_TIME_SEC;
+		error = ext3_mark_iloc_dirty(handle, inode, &is.iloc);
+		/*
+		 * The bh is consumed by ext3_mark_iloc_dirty, even with
+		 * error != 0.
+		 */
+		is.iloc.bh = NULL;
+		if (IS_SYNC(inode))
+			handle->h_sync = 1;
+	}
+
+cleanup:
+	brelse(is.iloc.bh);
+	brelse(bs.bh);
+	up_write(&EXT3_I(inode)->xattr_sem);
+	return error;
+}
+
+/*
+ * ext3_xattr_set()
+ *
+ * Like ext3_xattr_set_handle, but start from an inode. This extended
+ * attribute modification is a filesystem transaction by itself.
+ *
+ * Returns 0, or a negative error number on failure.
+ */
+int
+ext3_xattr_set(struct inode *inode, int name_index, const char *name,
+	       const void *value, size_t value_len, int flags)
+{
+	handle_t *handle;
+	int error, retries = 0;
+
+retry:
+	handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb));
+	if (IS_ERR(handle)) {
+		error = PTR_ERR(handle);
+	} else {
+		int error2;
+
+		error = ext3_xattr_set_handle(handle, inode, name_index, name,
+					      value, value_len, flags);
+		error2 = ext3_journal_stop(handle);
+		if (error == -ENOSPC &&
+		    ext3_should_retry_alloc(inode->i_sb, &retries))
+			goto retry;
+		if (error == 0)
+			error = error2;
+	}
+
+	return error;
+}
+
+/*
+ * ext3_xattr_delete_inode()
+ *
+ * Free extended attribute resources associated with this inode. This
+ * is called immediately before an inode is freed. We have exclusive
+ * access to the inode.
+ */
+void
+ext3_xattr_delete_inode(handle_t *handle, struct inode *inode)
+{
+	struct buffer_head *bh = NULL;
+
+	if (!EXT3_I(inode)->i_file_acl)
+		goto cleanup;
+	bh = sb_bread(inode->i_sb, EXT3_I(inode)->i_file_acl);
+	if (!bh) {
+		ext3_error(inode->i_sb, __FUNCTION__,
+			"inode %lu: block "E3FSBLK" read error", inode->i_ino,
+			EXT3_I(inode)->i_file_acl);
+		goto cleanup;
+	}
+	if (BHDR(bh)->h_magic != cpu_to_le32(EXT3_XATTR_MAGIC) ||
+	    BHDR(bh)->h_blocks != cpu_to_le32(1)) {
+		ext3_error(inode->i_sb, __FUNCTION__,
+			"inode %lu: bad block "E3FSBLK, inode->i_ino,
+			EXT3_I(inode)->i_file_acl);
+		goto cleanup;
+	}
+	ext3_xattr_release_block(handle, inode, bh);
+	EXT3_I(inode)->i_file_acl = 0;
+
+cleanup:
+	brelse(bh);
+}
+
+/*
+ * ext3_xattr_put_super()
+ *
+ * This is called when a file system is unmounted.
+ */
+void
+ext3_xattr_put_super(struct super_block *sb)
+{
+	mb_cache_shrink(sb->s_bdev);
+}
+
+/*
+ * ext3_xattr_cache_insert()
+ *
+ * Create a new entry in the extended attribute cache, and insert
+ * it unless such an entry is already in the cache.
+ *
+ * Returns 0, or a negative error number on failure.
+ */
+static void
+ext3_xattr_cache_insert(struct buffer_head *bh)
+{
+	__u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
+	struct mb_cache_entry *ce;
+	int error;
+
+	ce = mb_cache_entry_alloc(ext3_xattr_cache);
+	if (!ce) {
+		ea_bdebug(bh, "out of memory");
+		return;
+	}
+	error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
+	if (error) {
+		mb_cache_entry_free(ce);
+		if (error == -EBUSY) {
+			ea_bdebug(bh, "already in cache");
+			error = 0;
+		}
+	} else {
+		ea_bdebug(bh, "inserting [%x]", (int)hash);
+		mb_cache_entry_release(ce);
+	}
+}
+
+/*
+ * ext3_xattr_cmp()
+ *
+ * Compare two extended attribute blocks for equality.
+ *
+ * Returns 0 if the blocks are equal, 1 if they differ, and
+ * a negative error number on errors.
+ */
+static int
+ext3_xattr_cmp(struct ext3_xattr_header *header1,
+	       struct ext3_xattr_header *header2)
+{
+	struct ext3_xattr_entry *entry1, *entry2;
+
+	entry1 = ENTRY(header1+1);
+	entry2 = ENTRY(header2+1);
+	while (!IS_LAST_ENTRY(entry1)) {
+		if (IS_LAST_ENTRY(entry2))
+			return 1;
+		if (entry1->e_hash != entry2->e_hash ||
+		    entry1->e_name_index != entry2->e_name_index ||
+		    entry1->e_name_len != entry2->e_name_len ||
+		    entry1->e_value_size != entry2->e_value_size ||
+		    memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
+			return 1;
+		if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
+			return -EIO;
+		if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
+			   (char *)header2 + le16_to_cpu(entry2->e_value_offs),
+			   le32_to_cpu(entry1->e_value_size)))
+			return 1;
+
+		entry1 = EXT3_XATTR_NEXT(entry1);
+		entry2 = EXT3_XATTR_NEXT(entry2);
+	}
+	if (!IS_LAST_ENTRY(entry2))
+		return 1;
+	return 0;
+}
+
+/*
+ * ext3_xattr_cache_find()
+ *
+ * Find an identical extended attribute block.
+ *
+ * Returns a pointer to the block found, or NULL if such a block was
+ * not found or an error occurred.
+ */
+static struct buffer_head *
+ext3_xattr_cache_find(struct inode *inode, struct ext3_xattr_header *header,
+		      struct mb_cache_entry **pce)
+{
+	__u32 hash = le32_to_cpu(header->h_hash);
+	struct mb_cache_entry *ce;
+
+	if (!header->h_hash)
+		return NULL;  /* never share */
+	ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
+again:
+	ce = mb_cache_entry_find_first(ext3_xattr_cache, 0,
+				       inode->i_sb->s_bdev, hash);
+	while (ce) {
+		struct buffer_head *bh;
+
+		if (IS_ERR(ce)) {
+			if (PTR_ERR(ce) == -EAGAIN)
+				goto again;
+			break;
+		}
+		bh = sb_bread(inode->i_sb, ce->e_block);
+		if (!bh) {
+			ext3_error(inode->i_sb, __FUNCTION__,
+				"inode %lu: block %lu read error",
+				inode->i_ino, (unsigned long) ce->e_block);
+		} else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
+				EXT3_XATTR_REFCOUNT_MAX) {
+			ea_idebug(inode, "block %lu refcount %d>=%d",
+				  (unsigned long) ce->e_block,
+				  le32_to_cpu(BHDR(bh)->h_refcount),
+					  EXT3_XATTR_REFCOUNT_MAX);
+		} else if (ext3_xattr_cmp(header, BHDR(bh)) == 0) {
+			*pce = ce;
+			return bh;
+		}
+		brelse(bh);
+		ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
+	}
+	return NULL;
+}
+
+#define NAME_HASH_SHIFT 5
+#define VALUE_HASH_SHIFT 16
+
+/*
+ * ext3_xattr_hash_entry()
+ *
+ * Compute the hash of an extended attribute.
+ */
+static inline void ext3_xattr_hash_entry(struct ext3_xattr_header *header,
+					 struct ext3_xattr_entry *entry)
+{
+	__u32 hash = 0;
+	char *name = entry->e_name;
+	int n;
+
+	for (n=0; n < entry->e_name_len; n++) {
+		hash = (hash << NAME_HASH_SHIFT) ^
+		       (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
+		       *name++;
+	}
+
+	if (entry->e_value_block == 0 && entry->e_value_size != 0) {
+		__le32 *value = (__le32 *)((char *)header +
+			le16_to_cpu(entry->e_value_offs));
+		for (n = (le32_to_cpu(entry->e_value_size) +
+		     EXT3_XATTR_ROUND) >> EXT3_XATTR_PAD_BITS; n; n--) {
+			hash = (hash << VALUE_HASH_SHIFT) ^
+			       (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
+			       le32_to_cpu(*value++);
+		}
+	}
+	entry->e_hash = cpu_to_le32(hash);
+}
+
+#undef NAME_HASH_SHIFT
+#undef VALUE_HASH_SHIFT
+
+#define BLOCK_HASH_SHIFT 16
+
+/*
+ * ext3_xattr_rehash()
+ *
+ * Re-compute the extended attribute hash value after an entry has changed.
+ */
+static void ext3_xattr_rehash(struct ext3_xattr_header *header,
+			      struct ext3_xattr_entry *entry)
+{
+	struct ext3_xattr_entry *here;
+	__u32 hash = 0;
+
+	ext3_xattr_hash_entry(header, entry);
+	here = ENTRY(header+1);
+	while (!IS_LAST_ENTRY(here)) {
+		if (!here->e_hash) {
+			/* Block is not shared if an entry's hash value == 0 */
+			hash = 0;
+			break;
+		}
+		hash = (hash << BLOCK_HASH_SHIFT) ^
+		       (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
+		       le32_to_cpu(here->e_hash);
+		here = EXT3_XATTR_NEXT(here);
+	}
+	header->h_hash = cpu_to_le32(hash);
+}
+
+#undef BLOCK_HASH_SHIFT
+
+int __init
+init_ext3_xattr(void)
+{
+	ext3_xattr_cache = mb_cache_create("ext3_xattr", NULL,
+		sizeof(struct mb_cache_entry) +
+		sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
+	if (!ext3_xattr_cache)
+		return -ENOMEM;
+	return 0;
+}
+
+void
+exit_ext3_xattr(void)
+{
+	if (ext3_xattr_cache)
+		mb_cache_destroy(ext3_xattr_cache);
+	ext3_xattr_cache = NULL;
+}

fs/ext4/xattr.h

+/*
+  File: fs/ext3/xattr.h
+
+  On-disk format of extended attributes for the ext3 filesystem.
+
+  (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
+*/
+
+#include <linux/xattr.h>
+
+/* Magic value in attribute blocks */
+#define EXT3_XATTR_MAGIC		0xEA020000
+
+/* Maximum number of references to one attribute block */
+#define EXT3_XATTR_REFCOUNT_MAX		1024
+
+/* Name indexes */
+#define EXT3_XATTR_INDEX_USER			1
+#define EXT3_XATTR_INDEX_POSIX_ACL_ACCESS	2
+#define EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT	3
+#define EXT3_XATTR_INDEX_TRUSTED		4
+#define	EXT3_XATTR_INDEX_LUSTRE			5
+#define EXT3_XATTR_INDEX_SECURITY	        6
+
+struct ext3_xattr_header {
+	__le32	h_magic;	/* magic number for identification */
+	__le32	h_refcount;	/* reference count */
+	__le32	h_blocks;	/* number of disk blocks used */
+	__le32	h_hash;		/* hash value of all attributes */
+	__u32	h_reserved[4];	/* zero right now */
+};
+
+struct ext3_xattr_ibody_header {
+	__le32	h_magic;	/* magic number for identification */
+};
+
+struct ext3_xattr_entry {
+	__u8	e_name_len;	/* length of name */
+	__u8	e_name_index;	/* attribute name index */
+	__le16	e_value_offs;	/* offset in disk block of value */
+	__le32	e_value_block;	/* disk block attribute is stored on (n/i) */
+	__le32	e_value_size;	/* size of attribute value */
+	__le32	e_hash;		/* hash value of name and value */
+	char	e_name[0];	/* attribute name */
+};
+
+#define EXT3_XATTR_PAD_BITS		2
+#define EXT3_XATTR_PAD		(1<<EXT3_XATTR_PAD_BITS)
+#define EXT3_XATTR_ROUND		(EXT3_XATTR_PAD-1)
+#define EXT3_XATTR_LEN(name_len) \
+	(((name_len) + EXT3_XATTR_ROUND + \
+	sizeof(struct ext3_xattr_entry)) & ~EXT3_XATTR_ROUND)
+#define EXT3_XATTR_NEXT(entry) \
+	( (struct ext3_xattr_entry *)( \
+	  (char *)(entry) + EXT3_XATTR_LEN((entry)->e_name_len)) )
+#define EXT3_XATTR_SIZE(size) \
+	(((size) + EXT3_XATTR_ROUND) & ~EXT3_XATTR_ROUND)
+
+# ifdef CONFIG_EXT3_FS_XATTR
+
+extern struct xattr_handler ext3_xattr_user_handler;
+extern struct xattr_handler ext3_xattr_trusted_handler;
+extern struct xattr_handler ext3_xattr_acl_access_handler;
+extern struct xattr_handler ext3_xattr_acl_default_handler;
+extern struct xattr_handler ext3_xattr_security_handler;
+
+extern ssize_t ext3_listxattr(struct dentry *, char *, size_t);
+
+extern int ext3_xattr_get(struct inode *, int, const char *, void *, size_t);
+extern int ext3_xattr_list(struct inode *, char *, size_t);
+extern int ext3_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
+extern int ext3_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
+
+extern void ext3_xattr_delete_inode(handle_t *, struct inode *);
+extern void ext3_xattr_put_super(struct super_block *);
+
+extern int init_ext3_xattr(void);
+extern void exit_ext3_xattr(void);
+
+extern struct xattr_handler *ext3_xattr_handlers[];
+
+# else  /* CONFIG_EXT3_FS_XATTR */
+
+static inline int
+ext3_xattr_get(struct inode *inode, int name_index, const char *name,
+	       void *buffer, size_t size, int flags)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int
+ext3_xattr_list(struct inode *inode, void *buffer, size_t size)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int
+ext3_xattr_set(struct inode *inode, int name_index, const char *name,
+	       const void *value, size_t size, int flags)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline int
+ext3_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
+	       const char *name, const void *value, size_t size, int flags)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline void
+ext3_xattr_delete_inode(handle_t *handle, struct inode *inode)
+{
+}
+
+static inline void
+ext3_xattr_put_super(struct super_block *sb)
+{
+}
+
+static inline int
+init_ext3_xattr(void)
+{
+	return 0;
+}
+
+static inline void
+exit_ext3_xattr(void)
+{
+}
+
+#define ext3_xattr_handlers	NULL
+
+# endif  /* CONFIG_EXT3_FS_XATTR */
+
+#ifdef CONFIG_EXT3_FS_SECURITY
+extern int ext3_init_security(handle_t *handle, struct inode *inode,
+				struct inode *dir);
+#else
+static inline int ext3_init_security(handle_t *handle, struct inode *inode,
+				struct inode *dir)
+{
+	return 0;
+}
+#endif

fs/ext4/xattr_security.c

+/*
+ * linux/fs/ext3/xattr_security.c
+ * Handler for storing security labels as extended attributes.
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/smp_lock.h>
+#include <linux/ext3_jbd.h>
+#include <linux/ext3_fs.h>
+#include <linux/security.h>
+#include "xattr.h"
+
+static size_t
+ext3_xattr_security_list(struct inode *inode, char *list, size_t list_size,
+			 const char *name, size_t name_len)
+{
+	const size_t prefix_len = sizeof(XATTR_SECURITY_PREFIX)-1;
+	const size_t total_len = prefix_len + name_len + 1;
+
+
+	if (list && total_len <= list_size) {
+		memcpy(list, XATTR_SECURITY_PREFIX, prefix_len);
+		memcpy(list+prefix_len, name, name_len);
+		list[prefix_len + name_len] = '\0';
+	}
+	return total_len;
+}
+
+static int
+ext3_xattr_security_get(struct inode *inode, const char *name,
+		       void *buffer, size_t size)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return ext3_xattr_get(inode, EXT3_XATTR_INDEX_SECURITY, name,
+			      buffer, size);
+}
+
+static int
+ext3_xattr_security_set(struct inode *inode, const char *name,
+		       const void *value, size_t size, int flags)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return ext3_xattr_set(inode, EXT3_XATTR_INDEX_SECURITY, name,
+			      value, size, flags);
+}
+
+int
+ext3_init_security(handle_t *handle, struct inode *inode, struct inode *dir)
+{
+	int err;
+	size_t len;
+	void *value;
+	char *name;
+
+	err = security_inode_init_security(inode, dir, &name, &value, &len);
+	if (err) {
+		if (err == -EOPNOTSUPP)
+			return 0;
+		return err;
+	}
+	err = ext3_xattr_set_handle(handle, inode, EXT3_XATTR_INDEX_SECURITY,
+				    name, value, len, 0);
+	kfree(name);
+	kfree(value);
+	return err;
+}
+
+struct xattr_handler ext3_xattr_security_handler = {
+	.prefix	= XATTR_SECURITY_PREFIX,
+	.list	= ext3_xattr_security_list,
+	.get	= ext3_xattr_security_get,
+	.set	= ext3_xattr_security_set,
+};

fs/ext4/xattr_trusted.c

+/*
+ * linux/fs/ext3/xattr_trusted.c
+ * Handler for trusted extended attributes.
+ *
+ * Copyright (C) 2003 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/capability.h>
+#include <linux/fs.h>
+#include <linux/smp_lock.h>
+#include <linux/ext3_jbd.h>
+#include <linux/ext3_fs.h>
+#include "xattr.h"
+
+#define XATTR_TRUSTED_PREFIX "trusted."
+
+static size_t
+ext3_xattr_trusted_list(struct inode *inode, char *list, size_t list_size,
+			const char *name, size_t name_len)
+{
+	const size_t prefix_len = sizeof(XATTR_TRUSTED_PREFIX)-1;
+	const size_t total_len = prefix_len + name_len + 1;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return 0;
+
+	if (list && total_len <= list_size) {
+		memcpy(list, XATTR_TRUSTED_PREFIX, prefix_len);
+		memcpy(list+prefix_len, name, name_len);
+		list[prefix_len + name_len] = '\0';
+	}
+	return total_len;
+}
+
+static int
+ext3_xattr_trusted_get(struct inode *inode, const char *name,
+		       void *buffer, size_t size)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return ext3_xattr_get(inode, EXT3_XATTR_INDEX_TRUSTED, name,
+			      buffer, size);
+}
+
+static int
+ext3_xattr_trusted_set(struct inode *inode, const char *name,
+		       const void *value, size_t size, int flags)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	return ext3_xattr_set(inode, EXT3_XATTR_INDEX_TRUSTED, name,
+			      value, size, flags);
+}
+
+struct xattr_handler ext3_xattr_trusted_handler = {
+	.prefix	= XATTR_TRUSTED_PREFIX,
+	.list	= ext3_xattr_trusted_list,
+	.get	= ext3_xattr_trusted_get,
+	.set	= ext3_xattr_trusted_set,
+};

fs/ext4/xattr_user.c

+/*
+ * linux/fs/ext3/xattr_user.c
+ * Handler for extended user attributes.
+ *
+ * Copyright (C) 2001 by Andreas Gruenbacher, <a.gruenbacher@computer.org>
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/fs.h>
+#include <linux/smp_lock.h>
+#include <linux/ext3_jbd.h>
+#include <linux/ext3_fs.h>
+#include "xattr.h"
+
+#define XATTR_USER_PREFIX "user."
+
+static size_t
+ext3_xattr_user_list(struct inode *inode, char *list, size_t list_size,
+		     const char *name, size_t name_len)
+{
+	const size_t prefix_len = sizeof(XATTR_USER_PREFIX)-1;
+	const size_t total_len = prefix_len + name_len + 1;
+
+	if (!test_opt(inode->i_sb, XATTR_USER))
+		return 0;
+
+	if (list && total_len <= list_size) {
+		memcpy(list, XATTR_USER_PREFIX, prefix_len);
+		memcpy(list+prefix_len, name, name_len);
+		list[prefix_len + name_len] = '\0';
+	}
+	return total_len;
+}
+
+static int
+ext3_xattr_user_get(struct inode *inode, const char *name,
+		    void *buffer, size_t size)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	if (!test_opt(inode->i_sb, XATTR_USER))
+		return -EOPNOTSUPP;
+	return ext3_xattr_get(inode, EXT3_XATTR_INDEX_USER, name, buffer, size);
+}
+
+static int
+ext3_xattr_user_set(struct inode *inode, const char *name,
+		    const void *value, size_t size, int flags)
+{
+	if (strcmp(name, "") == 0)
+		return -EINVAL;
+	if (!test_opt(inode->i_sb, XATTR_USER))
+		return -EOPNOTSUPP;
+	return ext3_xattr_set(inode, EXT3_XATTR_INDEX_USER, name,
+			      value, size, flags);
+}
+
+struct xattr_handler ext3_xattr_user_handler = {
+	.prefix	= XATTR_USER_PREFIX,
+	.list	= ext3_xattr_user_list,
+	.get	= ext3_xattr_user_get,
+	.set	= ext3_xattr_user_set,
+};

include/linux/ext4_fs.h

+/*
+ *  linux/include/linux/ext3_fs.h
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/include/linux/minix_fs.h
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+#ifndef _LINUX_EXT3_FS_H
+#define _LINUX_EXT3_FS_H
+
+#include <linux/types.h>
+#include <linux/magic.h>
+
+/*
+ * The second extended filesystem constants/structures
+ */
+
+/*
+ * Define EXT3FS_DEBUG to produce debug messages
+ */
+#undef EXT3FS_DEBUG
+
+/*
+ * Define EXT3_RESERVATION to reserve data blocks for expanding files
+ */
+#define EXT3_DEFAULT_RESERVE_BLOCKS     8
+/*max window size: 1024(direct blocks) + 3([t,d]indirect blocks) */
+#define EXT3_MAX_RESERVE_BLOCKS         1027
+#define EXT3_RESERVE_WINDOW_NOT_ALLOCATED 0
+/*
+ * Always enable hashed directories
+ */
+#define CONFIG_EXT3_INDEX
+
+/*
+ * Debug code
+ */
+#ifdef EXT3FS_DEBUG
+#define ext3_debug(f, a...)						\
+	do {								\
+		printk (KERN_DEBUG "EXT3-fs DEBUG (%s, %d): %s:",	\
+			__FILE__, __LINE__, __FUNCTION__);		\
+		printk (KERN_DEBUG f, ## a);				\
+	} while (0)
+#else
+#define ext3_debug(f, a...)	do {} while (0)
+#endif
+
+/*
+ * Special inodes numbers
+ */
+#define	EXT3_BAD_INO		 1	/* Bad blocks inode */
+#define EXT3_ROOT_INO		 2	/* Root inode */
+#define EXT3_BOOT_LOADER_INO	 5	/* Boot loader inode */
+#define EXT3_UNDEL_DIR_INO	 6	/* Undelete directory inode */
+#define EXT3_RESIZE_INO		 7	/* Reserved group descriptors inode */
+#define EXT3_JOURNAL_INO	 8	/* Journal inode */
+
+/* First non-reserved inode for old ext3 filesystems */
+#define EXT3_GOOD_OLD_FIRST_INO	11
+
+/*
+ * Maximal count of links to a file
+ */
+#define EXT3_LINK_MAX		32000
+
+/*
+ * Macro-instructions used to manage several block sizes
+ */
+#define EXT3_MIN_BLOCK_SIZE		1024
+#define	EXT3_MAX_BLOCK_SIZE		4096
+#define EXT3_MIN_BLOCK_LOG_SIZE		  10
+#ifdef __KERNEL__
+# define EXT3_BLOCK_SIZE(s)		((s)->s_blocksize)
+#else
+# define EXT3_BLOCK_SIZE(s)		(EXT3_MIN_BLOCK_SIZE << (s)->s_log_block_size)
+#endif
+#define	EXT3_ADDR_PER_BLOCK(s)		(EXT3_BLOCK_SIZE(s) / sizeof (__u32))
+#ifdef __KERNEL__
+# define EXT3_BLOCK_SIZE_BITS(s)	((s)->s_blocksize_bits)
+#else
+# define EXT3_BLOCK_SIZE_BITS(s)	((s)->s_log_block_size + 10)
+#endif
+#ifdef __KERNEL__
+#define	EXT3_ADDR_PER_BLOCK_BITS(s)	(EXT3_SB(s)->s_addr_per_block_bits)
+#define EXT3_INODE_SIZE(s)		(EXT3_SB(s)->s_inode_size)
+#define EXT3_FIRST_INO(s)		(EXT3_SB(s)->s_first_ino)
+#else
+#define EXT3_INODE_SIZE(s)	(((s)->s_rev_level == EXT3_GOOD_OLD_REV) ? \
+				 EXT3_GOOD_OLD_INODE_SIZE : \
+				 (s)->s_inode_size)
+#define EXT3_FIRST_INO(s)	(((s)->s_rev_level == EXT3_GOOD_OLD_REV) ? \
+				 EXT3_GOOD_OLD_FIRST_INO : \
+				 (s)->s_first_ino)
+#endif
+
+/*
+ * Macro-instructions used to manage fragments
+ */
+#define EXT3_MIN_FRAG_SIZE		1024
+#define	EXT3_MAX_FRAG_SIZE		4096
+#define EXT3_MIN_FRAG_LOG_SIZE		  10
+#ifdef __KERNEL__
+# define EXT3_FRAG_SIZE(s)		(EXT3_SB(s)->s_frag_size)
+# define EXT3_FRAGS_PER_BLOCK(s)	(EXT3_SB(s)->s_frags_per_block)
+#else
+# define EXT3_FRAG_SIZE(s)		(EXT3_MIN_FRAG_SIZE << (s)->s_log_frag_size)
+# define EXT3_FRAGS_PER_BLOCK(s)	(EXT3_BLOCK_SIZE(s) / EXT3_FRAG_SIZE(s))
+#endif
+
+/*
+ * Structure of a blocks group descriptor
+ */
+struct ext3_group_desc
+{
+	__le32	bg_block_bitmap;		/* Blocks bitmap block */
+	__le32	bg_inode_bitmap;		/* Inodes bitmap block */
+	__le32	bg_inode_table;		/* Inodes table block */
+	__le16	bg_free_blocks_count;	/* Free blocks count */
+	__le16	bg_free_inodes_count;	/* Free inodes count */
+	__le16	bg_used_dirs_count;	/* Directories count */
+	__u16	bg_pad;
+	__le32	bg_reserved[3];
+};
+
+/*
+ * Macro-instructions used to manage group descriptors
+ */
+#ifdef __KERNEL__
+# define EXT3_BLOCKS_PER_GROUP(s)	(EXT3_SB(s)->s_blocks_per_group)
+# define EXT3_DESC_PER_BLOCK(s)		(EXT3_SB(s)->s_desc_per_block)
+# define EXT3_INODES_PER_GROUP(s)	(EXT3_SB(s)->s_inodes_per_group)
+# define EXT3_DESC_PER_BLOCK_BITS(s)	(EXT3_SB(s)->s_desc_per_block_bits)
+#else
+# define EXT3_BLOCKS_PER_GROUP(s)	((s)->s_blocks_per_group)
+# define EXT3_DESC_PER_BLOCK(s)		(EXT3_BLOCK_SIZE(s) / sizeof (struct ext3_group_desc))
+# define EXT3_INODES_PER_GROUP(s)	((s)->s_inodes_per_group)
+#endif
+
+/*
+ * Constants relative to the data blocks
+ */
+#define	EXT3_NDIR_BLOCKS		12
+#define	EXT3_IND_BLOCK			EXT3_NDIR_BLOCKS
+#define	EXT3_DIND_BLOCK			(EXT3_IND_BLOCK + 1)
+#define	EXT3_TIND_BLOCK			(EXT3_DIND_BLOCK + 1)
+#define	EXT3_N_BLOCKS			(EXT3_TIND_BLOCK + 1)
+
+/*
+ * Inode flags
+ */
+#define	EXT3_SECRM_FL			0x00000001 /* Secure deletion */
+#define	EXT3_UNRM_FL			0x00000002 /* Undelete */
+#define	EXT3_COMPR_FL			0x00000004 /* Compress file */
+#define EXT3_SYNC_FL			0x00000008 /* Synchronous updates */
+#define EXT3_IMMUTABLE_FL		0x00000010 /* Immutable file */
+#define EXT3_APPEND_FL			0x00000020 /* writes to file may only append */
+#define EXT3_NODUMP_FL			0x00000040 /* do not dump file */
+#define EXT3_NOATIME_FL			0x00000080 /* do not update atime */
+/* Reserved for compression usage... */
+#define EXT3_DIRTY_FL			0x00000100
+#define EXT3_COMPRBLK_FL		0x00000200 /* One or more compressed clusters */
+#define EXT3_NOCOMPR_FL			0x00000400 /* Don't compress */
+#define EXT3_ECOMPR_FL			0x00000800 /* Compression error */
+/* End compression flags --- maybe not all used */
+#define EXT3_INDEX_FL			0x00001000 /* hash-indexed directory */
+#define EXT3_IMAGIC_FL			0x00002000 /* AFS directory */
+#define EXT3_JOURNAL_DATA_FL		0x00004000 /* file data should be journaled */
+#define EXT3_NOTAIL_FL			0x00008000 /* file tail should not be merged */
+#define EXT3_DIRSYNC_FL			0x00010000 /* dirsync behaviour (directories only) */
+#define EXT3_TOPDIR_FL			0x00020000 /* Top of directory hierarchies*/
+#define EXT3_RESERVED_FL		0x80000000 /* reserved for ext3 lib */
+
+#define EXT3_FL_USER_VISIBLE		0x0003DFFF /* User visible flags */
+#define EXT3_FL_USER_MODIFIABLE		0x000380FF /* User modifiable flags */
+
+/*
+ * Inode dynamic state flags
+ */
+#define EXT3_STATE_JDATA		0x00000001 /* journaled data exists */
+#define EXT3_STATE_NEW			0x00000002 /* inode is newly created */
+#define EXT3_STATE_XATTR		0x00000004 /* has in-inode xattrs */
+
+/* Used to pass group descriptor data when online resize is done */
+struct ext3_new_group_input {
+	__u32 group;            /* Group number for this data */
+	__u32 block_bitmap;     /* Absolute block number of block bitmap */
+	__u32 inode_bitmap;     /* Absolute block number of inode bitmap */
+	__u32 inode_table;      /* Absolute block number of inode table start */
+	__u32 blocks_count;     /* Total number of blocks in this group */
+	__u16 reserved_blocks;  /* Number of reserved blocks in this group */
+	__u16 unused;
+};
+
+/* The struct ext3_new_group_input in kernel space, with free_blocks_count */
+struct ext3_new_group_data {
+	__u32 group;
+	__u32 block_bitmap;
+	__u32 inode_bitmap;
+	__u32 inode_table;
+	__u32 blocks_count;
+	__u16 reserved_blocks;
+	__u16 unused;
+	__u32 free_blocks_count;
+};
+
+
+/*
+ * ioctl commands
+ */
+#define	EXT3_IOC_GETFLAGS		FS_IOC_GETFLAGS
+#define	EXT3_IOC_SETFLAGS		FS_IOC_SETFLAGS
+#define	EXT3_IOC_GETVERSION		_IOR('f', 3, long)
+#define	EXT3_IOC_SETVERSION		_IOW('f', 4, long)
+#define EXT3_IOC_GROUP_EXTEND		_IOW('f', 7, unsigned long)
+#define EXT3_IOC_GROUP_ADD		_IOW('f', 8,struct ext3_new_group_input)
+#define	EXT3_IOC_GETVERSION_OLD		FS_IOC_GETVERSION
+#define	EXT3_IOC_SETVERSION_OLD		FS_IOC_SETVERSION
+#ifdef CONFIG_JBD_DEBUG
+#define EXT3_IOC_WAIT_FOR_READONLY	_IOR('f', 99, long)
+#endif
+#define EXT3_IOC_GETRSVSZ		_IOR('f', 5, long)
+#define EXT3_IOC_SETRSVSZ		_IOW('f', 6, long)
+
+/*
+ * ioctl commands in 32 bit emulation
+ */
+#define EXT3_IOC32_GETFLAGS		FS_IOC32_GETFLAGS
+#define EXT3_IOC32_SETFLAGS		FS_IOC32_SETFLAGS
+#define EXT3_IOC32_GETVERSION		_IOR('f', 3, int)
+#define EXT3_IOC32_SETVERSION		_IOW('f', 4, int)
+#define EXT3_IOC32_GETRSVSZ		_IOR('f', 5, int)
+#define EXT3_IOC32_SETRSVSZ		_IOW('f', 6, int)
+#define EXT3_IOC32_GROUP_EXTEND		_IOW('f', 7, unsigned int)
+#ifdef CONFIG_JBD_DEBUG
+#define EXT3_IOC32_WAIT_FOR_READONLY	_IOR('f', 99, int)
+#endif
+#define EXT3_IOC32_GETVERSION_OLD	FS_IOC32_GETVERSION
+#define EXT3_IOC32_SETVERSION_OLD	FS_IOC32_SETVERSION
+
+
+/*
+ *  Mount options
+ */
+struct ext3_mount_options {
+	unsigned long s_mount_opt;
+	uid_t s_resuid;
+	gid_t s_resgid;
+	unsigned long s_commit_interval;
+#ifdef CONFIG_QUOTA
+	int s_jquota_fmt;
+	char *s_qf_names[MAXQUOTAS];
+#endif
+};
+
+/*
+ * Structure of an inode on the disk
+ */
+struct ext3_inode {
+	__le16	i_mode;		/* File mode */
+	__le16	i_uid;		/* Low 16 bits of Owner Uid */
+	__le32	i_size;		/* Size in bytes */
+	__le32	i_atime;	/* Access time */
+	__le32	i_ctime;	/* Creation time */
+	__le32	i_mtime;	/* Modification time */
+	__le32	i_dtime;	/* Deletion Time */
+	__le16	i_gid;		/* Low 16 bits of Group Id */
+	__le16	i_links_count;	/* Links count */
+	__le32	i_blocks;	/* Blocks count */
+	__le32	i_flags;	/* File flags */
+	union {
+		struct {
+			__u32  l_i_reserved1;
+		} linux1;
+		struct {
+			__u32  h_i_translator;
+		} hurd1;
+		struct {
+			__u32  m_i_reserved1;
+		} masix1;
+	} osd1;				/* OS dependent 1 */
+	__le32	i_block[EXT3_N_BLOCKS];/* Pointers to blocks */
+	__le32	i_generation;	/* File version (for NFS) */
+	__le32	i_file_acl;	/* File ACL */
+	__le32	i_dir_acl;	/* Directory ACL */
+	__le32	i_faddr;	/* Fragment address */
+	union {
+		struct {
+			__u8	l_i_frag;	/* Fragment number */
+			__u8	l_i_fsize;	/* Fragment size */
+			__u16	i_pad1;
+			__le16	l_i_uid_high;	/* these 2 fields    */
+			__le16	l_i_gid_high;	/* were reserved2[0] */
+			__u32	l_i_reserved2;
+		} linux2;
+		struct {
+			__u8	h_i_frag;	/* Fragment number */
+			__u8	h_i_fsize;	/* Fragment size */
+			__u16	h_i_mode_high;
+			__u16	h_i_uid_high;
+			__u16	h_i_gid_high;
+			__u32	h_i_author;
+		} hurd2;
+		struct {
+			__u8	m_i_frag;	/* Fragment number */
+			__u8	m_i_fsize;	/* Fragment size */
+			__u16	m_pad1;
+			__u32	m_i_reserved2[2];
+		} masix2;
+	} osd2;				/* OS dependent 2 */
+	__le16	i_extra_isize;
+	__le16	i_pad1;
+};
+
+#define i_size_high	i_dir_acl
+
+#if defined(__KERNEL__) || defined(__linux__)
+#define i_reserved1	osd1.linux1.l_i_reserved1
+#define i_frag		osd2.linux2.l_i_frag
+#define i_fsize		osd2.linux2.l_i_fsize
+#define i_uid_low	i_uid
+#define i_gid_low	i_gid
+#define i_uid_high	osd2.linux2.l_i_uid_high
+#define i_gid_high	osd2.linux2.l_i_gid_high
+#define i_reserved2	osd2.linux2.l_i_reserved2
+
+#elif defined(__GNU__)
+
+#define i_translator	osd1.hurd1.h_i_translator
+#define i_frag		osd2.hurd2.h_i_frag;
+#define i_fsize		osd2.hurd2.h_i_fsize;
+#define i_uid_high	osd2.hurd2.h_i_uid_high
+#define i_gid_high	osd2.hurd2.h_i_gid_high
+#define i_author	osd2.hurd2.h_i_author
+
+#elif defined(__masix__)
+
+#define i_reserved1	osd1.masix1.m_i_reserved1
+#define i_frag		osd2.masix2.m_i_frag
+#define i_fsize		osd2.masix2.m_i_fsize
+#define i_reserved2	osd2.masix2.m_i_reserved2
+
+#endif /* defined(__KERNEL__) || defined(__linux__) */
+
+/*
+ * File system states
+ */
+#define	EXT3_VALID_FS			0x0001	/* Unmounted cleanly */
+#define	EXT3_ERROR_FS			0x0002	/* Errors detected */
+#define	EXT3_ORPHAN_FS			0x0004	/* Orphans being recovered */
+
+/*
+ * Mount flags
+ */
+#define EXT3_MOUNT_CHECK		0x00001	/* Do mount-time checks */
+#define EXT3_MOUNT_OLDALLOC		0x00002  /* Don't use the new Orlov allocator */
+#define EXT3_MOUNT_GRPID		0x00004	/* Create files with directory's group */
+#define EXT3_MOUNT_DEBUG		0x00008	/* Some debugging messages */
+#define EXT3_MOUNT_ERRORS_CONT		0x00010	/* Continue on errors */
+#define EXT3_MOUNT_ERRORS_RO		0x00020	/* Remount fs ro on errors */
+#define EXT3_MOUNT_ERRORS_PANIC		0x00040	/* Panic on errors */
+#define EXT3_MOUNT_MINIX_DF		0x00080	/* Mimics the Minix statfs */
+#define EXT3_MOUNT_NOLOAD		0x00100	/* Don't use existing journal*/
+#define EXT3_MOUNT_ABORT		0x00200	/* Fatal error detected */
+#define EXT3_MOUNT_DATA_FLAGS		0x00C00	/* Mode for data writes: */
+#define EXT3_MOUNT_JOURNAL_DATA		0x00400	/* Write data to journal */
+#define EXT3_MOUNT_ORDERED_DATA		0x00800	/* Flush data before commit */
+#define EXT3_MOUNT_WRITEBACK_DATA	0x00C00	/* No data ordering */
+#define EXT3_MOUNT_UPDATE_JOURNAL	0x01000	/* Update the journal format */
+#define EXT3_MOUNT_NO_UID32		0x02000  /* Disable 32-bit UIDs */
+#define EXT3_MOUNT_XATTR_USER		0x04000	/* Extended user attributes */
+#define EXT3_MOUNT_POSIX_ACL		0x08000	/* POSIX Access Control Lists */
+#define EXT3_MOUNT_RESERVATION		0x10000	/* Preallocation */
+#define EXT3_MOUNT_BARRIER		0x20000 /* Use block barriers */
+#define EXT3_MOUNT_NOBH			0x40000 /* No bufferheads */
+#define EXT3_MOUNT_QUOTA		0x80000 /* Some quota option set */
+#define EXT3_MOUNT_USRQUOTA		0x100000 /* "old" user quota */
+#define EXT3_MOUNT_GRPQUOTA		0x200000 /* "old" group quota */
+
+/* Compatibility, for having both ext2_fs.h and ext3_fs.h included at once */
+#ifndef _LINUX_EXT2_FS_H
+#define clear_opt(o, opt)		o &= ~EXT3_MOUNT_##opt
+#define set_opt(o, opt)			o |= EXT3_MOUNT_##opt
+#define test_opt(sb, opt)		(EXT3_SB(sb)->s_mount_opt & \
+					 EXT3_MOUNT_##opt)
+#else
+#define EXT2_MOUNT_NOLOAD		EXT3_MOUNT_NOLOAD
+#define EXT2_MOUNT_ABORT		EXT3_MOUNT_ABORT
+#define EXT2_MOUNT_DATA_FLAGS		EXT3_MOUNT_DATA_FLAGS
+#endif
+
+#define ext3_set_bit			ext2_set_bit
+#define ext3_set_bit_atomic		ext2_set_bit_atomic
+#define ext3_clear_bit			ext2_clear_bit
+#define ext3_clear_bit_atomic		ext2_clear_bit_atomic
+#define ext3_test_bit			ext2_test_bit
+#define ext3_find_first_zero_bit	ext2_find_first_zero_bit
+#define ext3_find_next_zero_bit		ext2_find_next_zero_bit
+
+/*
+ * Maximal mount counts between two filesystem checks
+ */
+#define EXT3_DFL_MAX_MNT_COUNT		20	/* Allow 20 mounts */
+#define EXT3_DFL_CHECKINTERVAL		0	/* Don't use interval check */
+
+/*
+ * Behaviour when detecting errors
+ */
+#define EXT3_ERRORS_CONTINUE		1	/* Continue execution */
+#define EXT3_ERRORS_RO			2	/* Remount fs read-only */
+#define EXT3_ERRORS_PANIC		3	/* Panic */
+#define EXT3_ERRORS_DEFAULT		EXT3_ERRORS_CONTINUE
+
+/*
+ * Structure of the super block
+ */
+struct ext3_super_block {
+/*00*/	__le32	s_inodes_count;		/* Inodes count */
+	__le32	s_blocks_count;		/* Blocks count */
+	__le32	s_r_blocks_count;	/* Reserved blocks count */
+	__le32	s_free_blocks_count;	/* Free blocks count */
+/*10*/	__le32	s_free_inodes_count;	/* Free inodes count */
+	__le32	s_first_data_block;	/* First Data Block */
+	__le32	s_log_block_size;	/* Block size */
+	__le32	s_log_frag_size;	/* Fragment size */
+/*20*/	__le32	s_blocks_per_group;	/* # Blocks per group */
+	__le32	s_frags_per_group;	/* # Fragments per group */
+	__le32	s_inodes_per_group;	/* # Inodes per group */
+	__le32	s_mtime;		/* Mount time */
+/*30*/	__le32	s_wtime;		/* Write time */
+	__le16	s_mnt_count;		/* Mount count */
+	__le16	s_max_mnt_count;	/* Maximal mount count */
+	__le16	s_magic;		/* Magic signature */
+	__le16	s_state;		/* File system state */
+	__le16	s_errors;		/* Behaviour when detecting errors */
+	__le16	s_minor_rev_level;	/* minor revision level */
+/*40*/	__le32	s_lastcheck;		/* time of last check */
+	__le32	s_checkinterval;	/* max. time between checks */
+	__le32	s_creator_os;		/* OS */
+	__le32	s_rev_level;		/* Revision level */
+/*50*/	__le16	s_def_resuid;		/* Default uid for reserved blocks */
+	__le16	s_def_resgid;		/* Default gid for reserved blocks */
+	/*
+	 * These fields are for EXT3_DYNAMIC_REV superblocks only.
+	 *
+	 * Note: the difference between the compatible feature set and
+	 * the incompatible feature set is that if there is a bit set
+	 * in the incompatible feature set that the kernel doesn't
+	 * know about, it should refuse to mount the filesystem.
+	 *
+	 * e2fsck's requirements are more strict; if it doesn't know
+	 * about a feature in either the compatible or incompatible
+	 * feature set, it must abort and not try to meddle with
+	 * things it doesn't understand...
+	 */
+	__le32	s_first_ino;		/* First non-reserved inode */
+	__le16   s_inode_size;		/* size of inode structure */
+	__le16	s_block_group_nr;	/* block group # of this superblock */
+	__le32	s_feature_compat;	/* compatible feature set */
+/*60*/	__le32	s_feature_incompat;	/* incompatible feature set */
+	__le32	s_feature_ro_compat;	/* readonly-compatible feature set */
+/*68*/	__u8	s_uuid[16];		/* 128-bit uuid for volume */
+/*78*/	char	s_volume_name[16];	/* volume name */
+/*88*/	char	s_last_mounted[64];	/* directory where last mounted */
+/*C8*/	__le32	s_algorithm_usage_bitmap; /* For compression */
+	/*
+	 * Performance hints.  Directory preallocation should only
+	 * happen if the EXT3_FEATURE_COMPAT_DIR_PREALLOC flag is on.
+	 */
+	__u8	s_prealloc_blocks;	/* Nr of blocks to try to preallocate*/
+	__u8	s_prealloc_dir_blocks;	/* Nr to preallocate for dirs */
+	__le16	s_reserved_gdt_blocks;	/* Per group desc for online growth */
+	/*
+	 * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
+	 */
+/*D0*/	__u8	s_journal_uuid[16];	/* uuid of journal superblock */
+/*E0*/	__le32	s_journal_inum;		/* inode number of journal file */
+	__le32	s_journal_dev;		/* device number of journal file */
+	__le32	s_last_orphan;		/* start of list of inodes to delete */
+	__le32	s_hash_seed[4];		/* HTREE hash seed */
+	__u8	s_def_hash_version;	/* Default hash version to use */
+	__u8	s_reserved_char_pad;
+	__u16	s_reserved_word_pad;
+	__le32	s_default_mount_opts;
+	__le32	s_first_meta_bg;	/* First metablock block group */
+	__u32	s_reserved[190];	/* Padding to the end of the block */
+};
+
+#ifdef __KERNEL__
+#include <linux/ext3_fs_i.h>
+#include <linux/ext3_fs_sb.h>
+static inline struct ext3_sb_info * EXT3_SB(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+static inline struct ext3_inode_info *EXT3_I(struct inode *inode)
+{
+	return container_of(inode, struct ext3_inode_info, vfs_inode);
+}
+
+static inline int ext3_valid_inum(struct super_block *sb, unsigned long ino)
+{
+	return ino == EXT3_ROOT_INO ||
+		ino == EXT3_JOURNAL_INO ||
+		ino == EXT3_RESIZE_INO ||
+		(ino >= EXT3_FIRST_INO(sb) &&
+		 ino <= le32_to_cpu(EXT3_SB(sb)->s_es->s_inodes_count));
+}
+#else
+/* Assume that user mode programs are passing in an ext3fs superblock, not
+ * a kernel struct super_block.  This will allow us to call the feature-test
+ * macros from user land. */
+#define EXT3_SB(sb)	(sb)
+#endif
+
+#define NEXT_ORPHAN(inode) EXT3_I(inode)->i_dtime
+
+/*
+ * Codes for operating systems
+ */
+#define EXT3_OS_LINUX		0
+#define EXT3_OS_HURD		1
+#define EXT3_OS_MASIX		2
+#define EXT3_OS_FREEBSD		3
+#define EXT3_OS_LITES		4
+
+/*
+ * Revision levels
+ */
+#define EXT3_GOOD_OLD_REV	0	/* The good old (original) format */
+#define EXT3_DYNAMIC_REV	1	/* V2 format w/ dynamic inode sizes */
+
+#define EXT3_CURRENT_REV	EXT3_GOOD_OLD_REV
+#define EXT3_MAX_SUPP_REV	EXT3_DYNAMIC_REV
+
+#define EXT3_GOOD_OLD_INODE_SIZE 128
+
+/*
+ * Feature set definitions
+ */
+
+#define EXT3_HAS_COMPAT_FEATURE(sb,mask)			\
+	( EXT3_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask) )
+#define EXT3_HAS_RO_COMPAT_FEATURE(sb,mask)			\
+	( EXT3_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask) )
+#define EXT3_HAS_INCOMPAT_FEATURE(sb,mask)			\
+	( EXT3_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask) )
+#define EXT3_SET_COMPAT_FEATURE(sb,mask)			\
+	EXT3_SB(sb)->s_es->s_feature_compat |= cpu_to_le32(mask)
+#define EXT3_SET_RO_COMPAT_FEATURE(sb,mask)			\
+	EXT3_SB(sb)->s_es->s_feature_ro_compat |= cpu_to_le32(mask)
+#define EXT3_SET_INCOMPAT_FEATURE(sb,mask)			\
+	EXT3_SB(sb)->s_es->s_feature_incompat |= cpu_to_le32(mask)
+#define EXT3_CLEAR_COMPAT_FEATURE(sb,mask)			\
+	EXT3_SB(sb)->s_es->s_feature_compat &= ~cpu_to_le32(mask)
+#define EXT3_CLEAR_RO_COMPAT_FEATURE(sb,mask)			\
+	EXT3_SB(sb)->s_es->s_feature_ro_compat &= ~cpu_to_le32(mask)
+#define EXT3_CLEAR_INCOMPAT_FEATURE(sb,mask)			\
+	EXT3_SB(sb)->s_es->s_feature_incompat &= ~cpu_to_le32(mask)
+
+#define EXT3_FEATURE_COMPAT_DIR_PREALLOC	0x0001
+#define EXT3_FEATURE_COMPAT_IMAGIC_INODES	0x0002
+#define EXT3_FEATURE_COMPAT_HAS_JOURNAL		0x0004
+#define EXT3_FEATURE_COMPAT_EXT_ATTR		0x0008
+#define EXT3_FEATURE_COMPAT_RESIZE_INODE	0x0010
+#define EXT3_FEATURE_COMPAT_DIR_INDEX		0x0020
+
+#define EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER	0x0001
+#define EXT3_FEATURE_RO_COMPAT_LARGE_FILE	0x0002
+#define EXT3_FEATURE_RO_COMPAT_BTREE_DIR	0x0004
+
+#define EXT3_FEATURE_INCOMPAT_COMPRESSION	0x0001
+#define EXT3_FEATURE_INCOMPAT_FILETYPE		0x0002
+#define EXT3_FEATURE_INCOMPAT_RECOVER		0x0004 /* Needs recovery */
+#define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV	0x0008 /* Journal device */
+#define EXT3_FEATURE_INCOMPAT_META_BG		0x0010
+
+#define EXT3_FEATURE_COMPAT_SUPP	EXT2_FEATURE_COMPAT_EXT_ATTR
+#define EXT3_FEATURE_INCOMPAT_SUPP	(EXT3_FEATURE_INCOMPAT_FILETYPE| \
+					 EXT3_FEATURE_INCOMPAT_RECOVER| \
+					 EXT3_FEATURE_INCOMPAT_META_BG)
+#define EXT3_FEATURE_RO_COMPAT_SUPP	(EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER| \
+					 EXT3_FEATURE_RO_COMPAT_LARGE_FILE| \
+					 EXT3_FEATURE_RO_COMPAT_BTREE_DIR)
+
+/*
+ * Default values for user and/or group using reserved blocks
+ */
+#define	EXT3_DEF_RESUID		0
+#define	EXT3_DEF_RESGID		0
+
+/*
+ * Default mount options
+ */
+#define EXT3_DEFM_DEBUG		0x0001
+#define EXT3_DEFM_BSDGROUPS	0x0002
+#define EXT3_DEFM_XATTR_USER	0x0004
+#define EXT3_DEFM_ACL		0x0008
+#define EXT3_DEFM_UID16		0x0010
+#define EXT3_DEFM_JMODE		0x0060
+#define EXT3_DEFM_JMODE_DATA	0x0020
+#define EXT3_DEFM_JMODE_ORDERED	0x0040
+#define EXT3_DEFM_JMODE_WBACK	0x0060
+
+/*
+ * Structure of a directory entry
+ */
+#define EXT3_NAME_LEN 255
+
+struct ext3_dir_entry {
+	__le32	inode;			/* Inode number */
+	__le16	rec_len;		/* Directory entry length */
+	__le16	name_len;		/* Name length */
+	char	name[EXT3_NAME_LEN];	/* File name */
+};
+
+/*
+ * The new version of the directory entry.  Since EXT3 structures are
+ * stored in intel byte order, and the name_len field could never be
+ * bigger than 255 chars, it's safe to reclaim the extra byte for the
+ * file_type field.
+ */
+struct ext3_dir_entry_2 {
+	__le32	inode;			/* Inode number */
+	__le16	rec_len;		/* Directory entry length */
+	__u8	name_len;		/* Name length */
+	__u8	file_type;
+	char	name[EXT3_NAME_LEN];	/* File name */
+};
+
+/*
+ * Ext3 directory file types.  Only the low 3 bits are used.  The
+ * other bits are reserved for now.
+ */
+#define EXT3_FT_UNKNOWN		0
+#define EXT3_FT_REG_FILE	1
+#define EXT3_FT_DIR		2
+#define EXT3_FT_CHRDEV		3
+#define EXT3_FT_BLKDEV		4
+#define EXT3_FT_FIFO		5
+#define EXT3_FT_SOCK		6
+#define EXT3_FT_SYMLINK		7
+
+#define EXT3_FT_MAX		8
+
+/*
+ * EXT3_DIR_PAD defines the directory entries boundaries
+ *
+ * NOTE: It must be a multiple of 4
+ */
+#define EXT3_DIR_PAD			4
+#define EXT3_DIR_ROUND			(EXT3_DIR_PAD - 1)
+#define EXT3_DIR_REC_LEN(name_len)	(((name_len) + 8 + EXT3_DIR_ROUND) & \
+					 ~EXT3_DIR_ROUND)
+/*
+ * Hash Tree Directory indexing
+ * (c) Daniel Phillips, 2001
+ */
+
+#ifdef CONFIG_EXT3_INDEX
+  #define is_dx(dir) (EXT3_HAS_COMPAT_FEATURE(dir->i_sb, \
+					      EXT3_FEATURE_COMPAT_DIR_INDEX) && \
+		      (EXT3_I(dir)->i_flags & EXT3_INDEX_FL))
+#define EXT3_DIR_LINK_MAX(dir) (!is_dx(dir) && (dir)->i_nlink >= EXT3_LINK_MAX)
+#define EXT3_DIR_LINK_EMPTY(dir) ((dir)->i_nlink == 2 || (dir)->i_nlink == 1)
+#else
+  #define is_dx(dir) 0
+#define EXT3_DIR_LINK_MAX(dir) ((dir)->i_nlink >= EXT3_LINK_MAX)
+#define EXT3_DIR_LINK_EMPTY(dir) ((dir)->i_nlink == 2)
+#endif
+
+/* Legal values for the dx_root hash_version field: */
+
+#define DX_HASH_LEGACY		0
+#define DX_HASH_HALF_MD4	1
+#define DX_HASH_TEA		2
+
+#ifdef __KERNEL__
+
+/* hash info structure used by the directory hash */
+struct dx_hash_info
+{
+	u32		hash;
+	u32		minor_hash;
+	int		hash_version;
+	u32		*seed;
+};
+
+#define EXT3_HTREE_EOF	0x7fffffff
+
+/*
+ * Control parameters used by ext3_htree_next_block
+ */
+#define HASH_NB_ALWAYS		1
+
+
+/*
+ * Describe an inode's exact location on disk and in memory
+ */
+struct ext3_iloc
+{
+	struct buffer_head *bh;
+	unsigned long offset;
+	unsigned long block_group;
+};
+
+static inline struct ext3_inode *ext3_raw_inode(struct ext3_iloc *iloc)
+{
+	return (struct ext3_inode *) (iloc->bh->b_data + iloc->offset);
+}
+
+/*
+ * This structure is stuffed into the struct file's private_data field
+ * for directories.  It is where we put information so that we can do
+ * readdir operations in hash tree order.
+ */
+struct dir_private_info {
+	struct rb_root	root;
+	struct rb_node	*curr_node;
+	struct fname	*extra_fname;
+	loff_t		last_pos;
+	__u32		curr_hash;
+	__u32		curr_minor_hash;
+	__u32		next_hash;
+};
+
+/* calculate the first block number of the group */
+static inline ext3_fsblk_t
+ext3_group_first_block_no(struct super_block *sb, unsigned long group_no)
+{
+	return group_no * (ext3_fsblk_t)EXT3_BLOCKS_PER_GROUP(sb) +
+		le32_to_cpu(EXT3_SB(sb)->s_es->s_first_data_block);
+}
+
+/*
+ * Special error return code only used by dx_probe() and its callers.
+ */
+#define ERR_BAD_DX_DIR	-75000
+
+/*
+ * Function prototypes
+ */
+
+/*
+ * Ok, these declarations are also in <linux/kernel.h> but none of the
+ * ext3 source programs needs to include it so they are duplicated here.
+ */
+# define NORET_TYPE    /**/
+# define ATTRIB_NORET  __attribute__((noreturn))
+# define NORET_AND     noreturn,
+
+/* balloc.c */
+extern int ext3_bg_has_super(struct super_block *sb, int group);
+extern unsigned long ext3_bg_num_gdb(struct super_block *sb, int group);
+extern ext3_fsblk_t ext3_new_block (handle_t *handle, struct inode *inode,
+			ext3_fsblk_t goal, int *errp);
+extern ext3_fsblk_t ext3_new_blocks (handle_t *handle, struct inode *inode,
+			ext3_fsblk_t goal, unsigned long *count, int *errp);
+extern void ext3_free_blocks (handle_t *handle, struct inode *inode,
+			ext3_fsblk_t block, unsigned long count);
+extern void ext3_free_blocks_sb (handle_t *handle, struct super_block *sb,
+				 ext3_fsblk_t block, unsigned long count,
+				unsigned long *pdquot_freed_blocks);
+extern ext3_fsblk_t ext3_count_free_blocks (struct super_block *);
+extern void ext3_check_blocks_bitmap (struct super_block *);
+extern struct ext3_group_desc * ext3_get_group_desc(struct super_block * sb,
+						    unsigned int block_group,
+						    struct buffer_head ** bh);
+extern int ext3_should_retry_alloc(struct super_block *sb, int *retries);
+extern void ext3_init_block_alloc_info(struct inode *);
+extern void ext3_rsv_window_add(struct super_block *sb, struct ext3_reserve_window_node *rsv);
+
+/* dir.c */
+extern int ext3_check_dir_entry(const char *, struct inode *,
+				struct ext3_dir_entry_2 *,
+				struct buffer_head *, unsigned long);
+extern int ext3_htree_store_dirent(struct file *dir_file, __u32 hash,
+				    __u32 minor_hash,
+				    struct ext3_dir_entry_2 *dirent);
+extern void ext3_htree_free_dir_info(struct dir_private_info *p);
+
+/* fsync.c */
+extern int ext3_sync_file (struct file *, struct dentry *, int);
+
+/* hash.c */
+extern int ext3fs_dirhash(const char *name, int len, struct
+			  dx_hash_info *hinfo);
+
+/* ialloc.c */
+extern struct inode * ext3_new_inode (handle_t *, struct inode *, int);
+extern void ext3_free_inode (handle_t *, struct inode *);
+extern struct inode * ext3_orphan_get (struct super_block *, unsigned long);
+extern unsigned long ext3_count_free_inodes (struct super_block *);
+extern unsigned long ext3_count_dirs (struct super_block *);
+extern void ext3_check_inodes_bitmap (struct super_block *);
+extern unsigned long ext3_count_free (struct buffer_head *, unsigned);
+
+
+/* inode.c */
+int ext3_forget(handle_t *handle, int is_metadata, struct inode *inode,
+		struct buffer_head *bh, ext3_fsblk_t blocknr);
+struct buffer_head * ext3_getblk (handle_t *, struct inode *, long, int, int *);
+struct buffer_head * ext3_bread (handle_t *, struct inode *, int, int, int *);
+int ext3_get_blocks_handle(handle_t *handle, struct inode *inode,
+	sector_t iblock, unsigned long maxblocks, struct buffer_head *bh_result,
+	int create, int extend_disksize);
+
+extern void ext3_read_inode (struct inode *);
+extern int  ext3_write_inode (struct inode *, int);
+extern int  ext3_setattr (struct dentry *, struct iattr *);
+extern void ext3_delete_inode (struct inode *);
+extern int  ext3_sync_inode (handle_t *, struct inode *);
+extern void ext3_discard_reservation (struct inode *);
+extern void ext3_dirty_inode(struct inode *);
+extern int ext3_change_inode_journal_flag(struct inode *, int);
+extern int ext3_get_inode_loc(struct inode *, struct ext3_iloc *);
+extern void ext3_truncate (struct inode *);
+extern void ext3_set_inode_flags(struct inode *);
+extern void ext3_set_aops(struct inode *inode);
+
+/* ioctl.c */
+extern int ext3_ioctl (struct inode *, struct file *, unsigned int,
+		       unsigned long);
+extern long ext3_compat_ioctl (struct file *, unsigned int, unsigned long);
+
+/* namei.c */
+extern int ext3_orphan_add(handle_t *, struct inode *);
+extern int ext3_orphan_del(handle_t *, struct inode *);
+extern int ext3_htree_fill_tree(struct file *dir_file, __u32 start_hash,
+				__u32 start_minor_hash, __u32 *next_hash);
+
+/* resize.c */
+extern int ext3_group_add(struct super_block *sb,
+				struct ext3_new_group_data *input);
+extern int ext3_group_extend(struct super_block *sb,
+				struct ext3_super_block *es,
+				ext3_fsblk_t n_blocks_count);
+
+/* super.c */
+extern void ext3_error (struct super_block *, const char *, const char *, ...)
+	__attribute__ ((format (printf, 3, 4)));
+extern void __ext3_std_error (struct super_block *, const char *, int);
+extern void ext3_abort (struct super_block *, const char *, const char *, ...)
+	__attribute__ ((format (printf, 3, 4)));
+extern void ext3_warning (struct super_block *, const char *, const char *, ...)
+	__attribute__ ((format (printf, 3, 4)));
+extern void ext3_update_dynamic_rev (struct super_block *sb);
+
+#define ext3_std_error(sb, errno)				\
+do {								\
+	if ((errno))						\
+		__ext3_std_error((sb), __FUNCTION__, (errno));	\
+} while (0)
+
+/*
+ * Inodes and files operations
+ */
+
+/* dir.c */
+extern const struct file_operations ext3_dir_operations;
+
+/* file.c */
+extern struct inode_operations ext3_file_inode_operations;
+extern const struct file_operations ext3_file_operations;
+
+/* namei.c */
+extern struct inode_operations ext3_dir_inode_operations;
+extern struct inode_operations ext3_special_inode_operations;
+
+/* symlink.c */
+extern struct inode_operations ext3_symlink_inode_operations;
+extern struct inode_operations ext3_fast_symlink_inode_operations;
+
+
+#endif	/* __KERNEL__ */
+
+#endif	/* _LINUX_EXT3_FS_H */

include/linux/ext4_fs_i.h

+/*
+ *  linux/include/linux/ext3_fs_i.h
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/include/linux/minix_fs_i.h
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+#ifndef _LINUX_EXT3_FS_I
+#define _LINUX_EXT3_FS_I
+
+#include <linux/rwsem.h>
+#include <linux/rbtree.h>
+#include <linux/seqlock.h>
+#include <linux/mutex.h>
+
+/* data type for block offset of block group */
+typedef int ext3_grpblk_t;
+
+/* data type for filesystem-wide blocks number */
+typedef unsigned long ext3_fsblk_t;
+
+#define E3FSBLK "%lu"
+
+struct ext3_reserve_window {
+	ext3_fsblk_t	_rsv_start;	/* First byte reserved */
+	ext3_fsblk_t	_rsv_end;	/* Last byte reserved or 0 */
+};
+
+struct ext3_reserve_window_node {
+	struct rb_node		rsv_node;
+	__u32			rsv_goal_size;
+	__u32			rsv_alloc_hit;
+	struct ext3_reserve_window	rsv_window;
+};
+
+struct ext3_block_alloc_info {
+	/* information about reservation window */
+	struct ext3_reserve_window_node	rsv_window_node;
+	/*
+	 * was i_next_alloc_block in ext3_inode_info
+	 * is the logical (file-relative) number of the
+	 * most-recently-allocated block in this file.
+	 * We use this for detecting linearly ascending allocation requests.
+	 */
+	__u32                   last_alloc_logical_block;
+	/*
+	 * Was i_next_alloc_goal in ext3_inode_info
+	 * is the *physical* companion to i_next_alloc_block.
+	 * it the the physical block number of the block which was most-recentl
+	 * allocated to this file.  This give us the goal (target) for the next
+	 * allocation when we detect linearly ascending requests.
+	 */
+	ext3_fsblk_t		last_alloc_physical_block;
+};
+
+#define rsv_start rsv_window._rsv_start
+#define rsv_end rsv_window._rsv_end
+
+/*
+ * third extended file system inode data in memory
+ */
+struct ext3_inode_info {
+	__le32	i_data[15];	/* unconverted */
+	__u32	i_flags;
+#ifdef EXT3_FRAGMENTS
+	__u32	i_faddr;
+	__u8	i_frag_no;
+	__u8	i_frag_size;
+#endif
+	ext3_fsblk_t	i_file_acl;
+	__u32	i_dir_acl;
+	__u32	i_dtime;
+
+	/*
+	 * i_block_group is the number of the block group which contains
+	 * this file's inode.  Constant across the lifetime of the inode,
+	 * it is ued for making block allocation decisions - we try to
+	 * place a file's data blocks near its inode block, and new inodes
+	 * near to their parent directory's inode.
+	 */
+	__u32	i_block_group;
+	__u32	i_state;		/* Dynamic state flags for ext3 */
+
+	/* block reservation info */
+	struct ext3_block_alloc_info *i_block_alloc_info;
+
+	__u32	i_dir_start_lookup;
+#ifdef CONFIG_EXT3_FS_XATTR
+	/*
+	 * Extended attributes can be read independently of the main file
+	 * data. Taking i_mutex even when reading would cause contention
+	 * between readers of EAs and writers of regular file data, so
+	 * instead we synchronize on xattr_sem when reading or changing
+	 * EAs.
+	 */
+	struct rw_semaphore xattr_sem;
+#endif
+#ifdef CONFIG_EXT3_FS_POSIX_ACL
+	struct posix_acl	*i_acl;
+	struct posix_acl	*i_default_acl;
+#endif
+
+	struct list_head i_orphan;	/* unlinked but open inodes */
+
+	/*
+	 * i_disksize keeps track of what the inode size is ON DISK, not
+	 * in memory.  During truncate, i_size is set to the new size by
+	 * the VFS prior to calling ext3_truncate(), but the filesystem won't
+	 * set i_disksize to 0 until the truncate is actually under way.
+	 *
+	 * The intent is that i_disksize always represents the blocks which
+	 * are used by this file.  This allows recovery to restart truncate
+	 * on orphans if we crash during truncate.  We actually write i_disksize
+	 * into the on-disk inode when writing inodes out, instead of i_size.
+	 *
+	 * The only time when i_disksize and i_size may be different is when
+	 * a truncate is in progress.  The only things which change i_disksize
+	 * are ext3_get_block (growth) and ext3_truncate (shrinkth).
+	 */
+	loff_t	i_disksize;
+
+	/* on-disk additional length */
+	__u16 i_extra_isize;
+
+	/*
+	 * truncate_mutex is for serialising ext3_truncate() against
+	 * ext3_getblock().  In the 2.4 ext2 design, great chunks of inode's
+	 * data tree are chopped off during truncate. We can't do that in
+	 * ext3 because whenever we perform intermediate commits during
+	 * truncate, the inode and all the metadata blocks *must* be in a
+	 * consistent state which allows truncation of the orphans to restart
+	 * during recovery.  Hence we must fix the get_block-vs-truncate race
+	 * by other means, so we have truncate_mutex.
+	 */
+	struct mutex truncate_mutex;
+	struct inode vfs_inode;
+};
+
+#endif	/* _LINUX_EXT3_FS_I */

include/linux/ext4_fs_sb.h

+/*
+ *  linux/include/linux/ext3_fs_sb.h
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ *  from
+ *
+ *  linux/include/linux/minix_fs_sb.h
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+#ifndef _LINUX_EXT3_FS_SB
+#define _LINUX_EXT3_FS_SB
+
+#ifdef __KERNEL__
+#include <linux/timer.h>
+#include <linux/wait.h>
+#include <linux/blockgroup_lock.h>
+#include <linux/percpu_counter.h>
+#endif
+#include <linux/rbtree.h>
+
+/*
+ * third extended-fs super-block data in memory
+ */
+struct ext3_sb_info {
+	unsigned long s_frag_size;	/* Size of a fragment in bytes */
+	unsigned long s_frags_per_block;/* Number of fragments per block */
+	unsigned long s_inodes_per_block;/* Number of inodes per block */
+	unsigned long s_frags_per_group;/* Number of fragments in a group */
+	unsigned long s_blocks_per_group;/* Number of blocks in a group */
+	unsigned long s_inodes_per_group;/* Number of inodes in a group */
+	unsigned long s_itb_per_group;	/* Number of inode table blocks per group */
+	unsigned long s_gdb_count;	/* Number of group descriptor blocks */
+	unsigned long s_desc_per_block;	/* Number of group descriptors per block */
+	unsigned long s_groups_count;	/* Number of groups in the fs */
+	struct buffer_head * s_sbh;	/* Buffer containing the super block */
+	struct ext3_super_block * s_es;	/* Pointer to the super block in the buffer */
+	struct buffer_head ** s_group_desc;
+	unsigned long  s_mount_opt;
+	uid_t s_resuid;
+	gid_t s_resgid;
+	unsigned short s_mount_state;
+	unsigned short s_pad;
+	int s_addr_per_block_bits;
+	int s_desc_per_block_bits;
+	int s_inode_size;
+	int s_first_ino;
+	spinlock_t s_next_gen_lock;
+	u32 s_next_generation;
+	u32 s_hash_seed[4];
+	int s_def_hash_version;
+	struct percpu_counter s_freeblocks_counter;
+	struct percpu_counter s_freeinodes_counter;
+	struct percpu_counter s_dirs_counter;
+	struct blockgroup_lock s_blockgroup_lock;
+
+	/* root of the per fs reservation window tree */
+	spinlock_t s_rsv_window_lock;
+	struct rb_root s_rsv_window_root;
+	struct ext3_reserve_window_node s_rsv_window_head;
+
+	/* Journaling */
+	struct inode * s_journal_inode;
+	struct journal_s * s_journal;
+	struct list_head s_orphan;
+	unsigned long s_commit_interval;
+	struct block_device *journal_bdev;
+#ifdef CONFIG_JBD_DEBUG
+	struct timer_list turn_ro_timer;	/* For turning read-only (crash simulation) */
+	wait_queue_head_t ro_wait_queue;	/* For people waiting for the fs to go read-only */
+#endif
+#ifdef CONFIG_QUOTA
+	char *s_qf_names[MAXQUOTAS];		/* Names of quota files with journalled quota */
+	int s_jquota_fmt;			/* Format of quota to use */
+#endif
+};
+
+#endif	/* _LINUX_EXT3_FS_SB */

include/linux/ext4_jbd.h

+/*
+ * linux/include/linux/ext3_jbd.h
+ *
+ * Written by Stephen C. Tweedie <sct@redhat.com>, 1999
+ *
+ * Copyright 1998--1999 Red Hat corp --- All Rights Reserved
+ *
+ * This file is part of the Linux kernel and is made available under
+ * the terms of the GNU General Public License, version 2, or at your
+ * option, any later version, incorporated herein by reference.
+ *
+ * Ext3-specific journaling extensions.
+ */
+
+#ifndef _LINUX_EXT3_JBD_H
+#define _LINUX_EXT3_JBD_H
+
+#include <linux/fs.h>
+#include <linux/jbd.h>
+#include <linux/ext3_fs.h>
+
+#define EXT3_JOURNAL(inode)	(EXT3_SB((inode)->i_sb)->s_journal)
+
+/* Define the number of blocks we need to account to a transaction to
+ * modify one block of data.
+ *
+ * We may have to touch one inode, one bitmap buffer, up to three
+ * indirection blocks, the group and superblock summaries, and the data
+ * block to complete the transaction.  */
+
+#define EXT3_SINGLEDATA_TRANS_BLOCKS	8U
+
+/* Extended attribute operations touch at most two data buffers,
+ * two bitmap buffers, and two group summaries, in addition to the inode
+ * and the superblock, which are already accounted for. */
+
+#define EXT3_XATTR_TRANS_BLOCKS		6U
+
+/* Define the minimum size for a transaction which modifies data.  This
+ * needs to take into account the fact that we may end up modifying two
+ * quota files too (one for the group, one for the user quota).  The
+ * superblock only gets updated once, of course, so don't bother
+ * counting that again for the quota updates. */
+
+#define EXT3_DATA_TRANS_BLOCKS(sb)	(EXT3_SINGLEDATA_TRANS_BLOCKS + \
+					 EXT3_XATTR_TRANS_BLOCKS - 2 + \
+					 2*EXT3_QUOTA_TRANS_BLOCKS(sb))
+
+/* Delete operations potentially hit one directory's namespace plus an
+ * entire inode, plus arbitrary amounts of bitmap/indirection data.  Be
+ * generous.  We can grow the delete transaction later if necessary. */
+
+#define EXT3_DELETE_TRANS_BLOCKS(sb)	(2 * EXT3_DATA_TRANS_BLOCKS(sb) + 64)
+
+/* Define an arbitrary limit for the amount of data we will anticipate
+ * writing to any given transaction.  For unbounded transactions such as
+ * write(2) and truncate(2) we can write more than this, but we always
+ * start off at the maximum transaction size and grow the transaction
+ * optimistically as we go. */
+
+#define EXT3_MAX_TRANS_DATA		64U
+
+/* We break up a large truncate or write transaction once the handle's
+ * buffer credits gets this low, we need either to extend the
+ * transaction or to start a new one.  Reserve enough space here for
+ * inode, bitmap, superblock, group and indirection updates for at least
+ * one block, plus two quota updates.  Quota allocations are not
+ * needed. */
+
+#define EXT3_RESERVE_TRANS_BLOCKS	12U
+
+#define EXT3_INDEX_EXTRA_TRANS_BLOCKS	8
+
+#ifdef CONFIG_QUOTA
+/* Amount of blocks needed for quota update - we know that the structure was
+ * allocated so we need to update only inode+data */
+#define EXT3_QUOTA_TRANS_BLOCKS(sb) (test_opt(sb, QUOTA) ? 2 : 0)
+/* Amount of blocks needed for quota insert/delete - we do some block writes
+ * but inode, sb and group updates are done only once */
+#define EXT3_QUOTA_INIT_BLOCKS(sb) (test_opt(sb, QUOTA) ? (DQUOT_INIT_ALLOC*\
+		(EXT3_SINGLEDATA_TRANS_BLOCKS-3)+3+DQUOT_INIT_REWRITE) : 0)
+#define EXT3_QUOTA_DEL_BLOCKS(sb) (test_opt(sb, QUOTA) ? (DQUOT_DEL_ALLOC*\
+		(EXT3_SINGLEDATA_TRANS_BLOCKS-3)+3+DQUOT_DEL_REWRITE) : 0)
+#else
+#define EXT3_QUOTA_TRANS_BLOCKS(sb) 0
+#define EXT3_QUOTA_INIT_BLOCKS(sb) 0
+#define EXT3_QUOTA_DEL_BLOCKS(sb) 0
+#endif
+
+int
+ext3_mark_iloc_dirty(handle_t *handle,
+		     struct inode *inode,
+		     struct ext3_iloc *iloc);
+
+/*
+ * On success, We end up with an outstanding reference count against
+ * iloc->bh.  This _must_ be cleaned up later.
+ */
+
+int ext3_reserve_inode_write(handle_t *handle, struct inode *inode,
+			struct ext3_iloc *iloc);
+
+int ext3_mark_inode_dirty(handle_t *handle, struct inode *inode);
+
+/*
+ * Wrapper functions with which ext3 calls into JBD.  The intent here is
+ * to allow these to be turned into appropriate stubs so ext3 can control
+ * ext2 filesystems, so ext2+ext3 systems only nee one fs.  This work hasn't
+ * been done yet.
+ */
+
+void ext3_journal_abort_handle(const char *caller, const char *err_fn,
+		struct buffer_head *bh, handle_t *handle, int err);
+
+static inline int
+__ext3_journal_get_undo_access(const char *where, handle_t *handle,
+				struct buffer_head *bh)
+{
+	int err = journal_get_undo_access(handle, bh);
+	if (err)
+		ext3_journal_abort_handle(where, __FUNCTION__, bh, handle,err);
+	return err;
+}
+
+static inline int
+__ext3_journal_get_write_access(const char *where, handle_t *handle,
+				struct buffer_head *bh)
+{
+	int err = journal_get_write_access(handle, bh);
+	if (err)
+		ext3_journal_abort_handle(where, __FUNCTION__, bh, handle,err);
+	return err;
+}
+
+static inline void
+ext3_journal_release_buffer(handle_t *handle, struct buffer_head *bh)
+{
+	journal_release_buffer(handle, bh);
+}
+
+static inline int
+__ext3_journal_forget(const char *where, handle_t *handle, struct buffer_head *bh)
+{
+	int err = journal_forget(handle, bh);
+	if (err)
+		ext3_journal_abort_handle(where, __FUNCTION__, bh, handle,err);
+	return err;
+}
+
+static inline int
+__ext3_journal_revoke(const char *where, handle_t *handle,
+		      unsigned long blocknr, struct buffer_head *bh)
+{
+	int err = journal_revoke(handle, blocknr, bh);
+	if (err)
+		ext3_journal_abort_handle(where, __FUNCTION__, bh, handle,err);
+	return err;
+}
+
+static inline int
+__ext3_journal_get_create_access(const char *where,
+				 handle_t *handle, struct buffer_head *bh)
+{
+	int err = journal_get_create_access(handle, bh);
+	if (err)
+		ext3_journal_abort_handle(where, __FUNCTION__, bh, handle,err);
+	return err;
+}
+
+static inline int
+__ext3_journal_dirty_metadata(const char *where,
+			      handle_t *handle, struct buffer_head *bh)
+{
+	int err = journal_dirty_metadata(handle, bh);
+	if (err)
+		ext3_journal_abort_handle(where, __FUNCTION__, bh, handle,err);
+	return err;
+}
+
+
+#define ext3_journal_get_undo_access(handle, bh) \
+	__ext3_journal_get_undo_access(__FUNCTION__, (handle), (bh))
+#define ext3_journal_get_write_access(handle, bh) \
+	__ext3_journal_get_write_access(__FUNCTION__, (handle), (bh))
+#define ext3_journal_revoke(handle, blocknr, bh) \
+	__ext3_journal_revoke(__FUNCTION__, (handle), (blocknr), (bh))
+#define ext3_journal_get_create_access(handle, bh) \
+	__ext3_journal_get_create_access(__FUNCTION__, (handle), (bh))
+#define ext3_journal_dirty_metadata(handle, bh) \
+	__ext3_journal_dirty_metadata(__FUNCTION__, (handle), (bh))
+#define ext3_journal_forget(handle, bh) \
+	__ext3_journal_forget(__FUNCTION__, (handle), (bh))
+
+int ext3_journal_dirty_data(handle_t *handle, struct buffer_head *bh);
+
+handle_t *ext3_journal_start_sb(struct super_block *sb, int nblocks);
+int __ext3_journal_stop(const char *where, handle_t *handle);
+
+static inline handle_t *ext3_journal_start(struct inode *inode, int nblocks)
+{
+	return ext3_journal_start_sb(inode->i_sb, nblocks);
+}
+
+#define ext3_journal_stop(handle) \
+	__ext3_journal_stop(__FUNCTION__, (handle))
+
+static inline handle_t *ext3_journal_current_handle(void)
+{
+	return journal_current_handle();
+}
+
+static inline int ext3_journal_extend(handle_t *handle, int nblocks)
+{
+	return journal_extend(handle, nblocks);
+}
+
+static inline int ext3_journal_restart(handle_t *handle, int nblocks)
+{
+	return journal_restart(handle, nblocks);
+}
+
+static inline int ext3_journal_blocks_per_page(struct inode *inode)
+{
+	return journal_blocks_per_page(inode);
+}
+
+static inline int ext3_journal_force_commit(journal_t *journal)
+{
+	return journal_force_commit(journal);
+}
+
+/* super.c */
+int ext3_force_commit(struct super_block *sb);
+
+static inline int ext3_should_journal_data(struct inode *inode)
+{
+	if (!S_ISREG(inode->i_mode))
+		return 1;
+	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT3_MOUNT_JOURNAL_DATA)
+		return 1;
+	if (EXT3_I(inode)->i_flags & EXT3_JOURNAL_DATA_FL)
+		return 1;
+	return 0;
+}
+
+static inline int ext3_should_order_data(struct inode *inode)
+{
+	if (!S_ISREG(inode->i_mode))
+		return 0;
+	if (EXT3_I(inode)->i_flags & EXT3_JOURNAL_DATA_FL)
+		return 0;
+	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT3_MOUNT_ORDERED_DATA)
+		return 1;
+	return 0;
+}
+
+static inline int ext3_should_writeback_data(struct inode *inode)
+{
+	if (!S_ISREG(inode->i_mode))
+		return 0;
+	if (EXT3_I(inode)->i_flags & EXT3_JOURNAL_DATA_FL)
+		return 0;
+	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT3_MOUNT_WRITEBACK_DATA)
+		return 1;
+	return 0;
+}
+
+#endif	/* _LINUX_EXT3_JBD_H */