Merge branch 'for-linus' of git://git.open-osd.org/linux-open-osd

* 'for-linus' of git://git.open-osd.org/linux-open-osd:
  fs: Add exofs to Kernel build
  exofs: Documentation
  exofs: export_operations
  exofs: super_operations and file_system_type
  exofs: dir_inode and directory operations
  exofs: address_space_operations
  exofs: symlink_inode and fast_symlink_inode operations
  exofs: file and file_inode operations
  exofs: Kbuild, Headers and osd utils

Documentation/filesystems/exofs.txt

+===============================================================================
+WHAT IS EXOFS?
+===============================================================================
+
+exofs is a file system that uses an OSD and exports the API of a normal Linux
+file system. Users access exofs like any other local file system, and exofs
+will in turn issue commands to the local OSD initiator.
+
+OSD is a new T10 command set that views storage devices not as a large/flat
+array of sectors but as a container of objects, each having a length, quota,
+time attributes and more. Each object is addressed by a 64bit ID, and is
+contained in a 64bit ID partition. Each object has associated attributes
+attached to it, which are integral part of the object and provide metadata about
+the object. The standard defines some common obligatory attributes, but user
+attributes can be added as needed.
+
+===============================================================================
+ENVIRONMENT
+===============================================================================
+
+To use this file system, you need to have an object store to run it on.  You
+may download a target from:
+http://open-osd.org
+
+See Documentation/scsi/osd.txt for how to setup a working osd environment.
+
+===============================================================================
+USAGE
+===============================================================================
+
+1. Download and compile exofs and open-osd initiator:
+  You need an external Kernel source tree or kernel headers from your
+  distribution. (anything based on 2.6.26 or later).
+
+  a. download open-osd including exofs source using:
+     [parent-directory]$ git clone git://git.open-osd.org/open-osd.git
+
+  b. Build the library module like this:
+     [parent-directory]$ make -C KSRC=$(KER_DIR) open-osd
+
+     This will build both the open-osd initiator as well as the exofs kernel
+     module. Use whatever parameters you compiled your Kernel with and
+     $(KER_DIR) above pointing to the Kernel you compile against. See the file
+     open-osd/top-level-Makefile for an example.
+
+2. Get the OSD initiator and target set up properly, and login to the target.
+  See Documentation/scsi/osd.txt for farther instructions. Also see ./do-osd
+  for example script that does all these steps.
+
+3. Insmod the exofs.ko module:
+   [exofs]$ insmod exofs.ko
+
+4. Make sure the directory where you want to mount exists. If not, create it.
+   (For example, mkdir /mnt/exofs)
+
+5. At first run you will need to invoke the mkfs.exofs application
+
+   As an example, this will create the file system on:
+   /dev/osd0 partition ID 65536
+
+   mkfs.exofs --pid=65536 --format /dev/osd0
+
+   The --format is optional if not specified no OSD_FORMAT will be
+   preformed and a clean file system will be created in the specified pid,
+   in the available space of the target. (Use --format=size_in_meg to limit
+   the total LUN space available)
+
+   If pid already exist it will be deleted and a new one will be created in it's
+   place. Be careful.
+
+   An exofs lives inside a single OSD partition. You can create multiple exofs
+   filesystems on the same device using multiple pids.
+
+   (run mkfs.exofs without any parameters for usage help message)
+
+6. Mount the file system.
+
+   For example, to mount /dev/osd0, partition ID 0x10000 on /mnt/exofs:
+
+	mount -t exofs -o pid=65536 /dev/osd0 /mnt/exofs/
+
+7. For reference (See do-exofs example script):
+	do-exofs start - an example of how to perform the above steps.
+	do-exofs stop -  an example of how to unmount the file system.
+	do-exofs format - an example of how to format and mkfs a new exofs.
+
+8. Extra compilation flags (uncomment in fs/exofs/Kbuild):
+	CONFIG_EXOFS_DEBUG - for debug messages and extra checks.
+
+===============================================================================
+exofs mount options
+===============================================================================
+Similar to any mount command:
+	mount -t exofs -o exofs_options /dev/osdX mount_exofs_directory
+
+Where:
+    -t exofs: specifies the exofs file system
+
+    /dev/osdX: X is a decimal number. /dev/osdX was created after a successful
+               login into an OSD target.
+
+    mount_exofs_directory: The directory to mount the file system on
+
+    exofs specific options: Options are separated by commas (,)
+		pid=<integer> - The partition number to mount/create as
+                                container of the filesystem.
+                                This option is mandatory
+                to=<integer>  - Timeout in ticks for a single command
+                                default is (60 * HZ) [for debugging only]
+
+===============================================================================
+DESIGN
+===============================================================================
+
+* The file system control block (AKA on-disk superblock) resides in an object
+  with a special ID (defined in common.h).
+  Information included in the file system control block is used to fill the
+  in-memory superblock structure at mount time. This object is created before
+  the file system is used by mkexofs.c It contains information such as:
+	- The file system's magic number
+	- The next inode number to be allocated
+
+* Each file resides in its own object and contains the data (and it will be
+  possible to extend the file over multiple objects, though this has not been
+  implemented yet).
+
+* A directory is treated as a file, and essentially contains a list of <file
+  name, inode #> pairs for files that are found in that directory. The object
+  IDs correspond to the files' inode numbers and will be allocated according to
+  a bitmap (stored in a separate object). Now they are allocated using a
+  counter.
+
+* Each file's control block (AKA on-disk inode) is stored in its object's
+  attributes. This applies to both regular files and other types (directories,
+  device files, symlinks, etc.).
+
+* Credentials are generated per object (inode and superblock) when they is
+  created in memory (read off disk or created). The credential works for all
+  operations and is used as long as the object remains in memory.
+
+* Async OSD operations are used whenever possible, but the target may execute
+  them out of order. The operations that concern us are create, delete,
+  readpage, writepage, update_inode, and truncate. The following pairs of
+  operations should execute in the order written, and we need to prevent them
+  from executing in reverse order:
+	- The following are handled with the OBJ_CREATED and OBJ_2BCREATED
+	  flags. OBJ_CREATED is set when we know the object exists on the OSD -
+	  in create's callback function, and when we successfully do a read_inode.
+	  OBJ_2BCREATED is set in the beginning of the create function, so we
+	  know that we should wait.
+		- create/delete: delete should wait until the object is created
+		  on the OSD.
+		- create/readpage: readpage should be able to return a page
+		  full of zeroes in this case. If there was a write already
+		  en-route (i.e. create, writepage, readpage) then the page
+		  would be locked, and so it would really be the same as
+		  create/writepage.
+		- create/writepage: if writepage is called for a sync write, it
+		  should wait until the object is created on the OSD.
+		  Otherwise, it should just return.
+		- create/truncate: truncate should wait until the object is
+		  created on the OSD.
+		- create/update_inode: update_inode should wait until the
+		  object is created on the OSD.
+	- Handled by VFS locks:
+		- readpage/delete: shouldn't happen because of page lock.
+		- writepage/delete: shouldn't happen because of page lock.
+		- readpage/writepage: shouldn't happen because of page lock.
+
+===============================================================================
+LICENSE/COPYRIGHT
+===============================================================================
+The exofs file system is based on ext2 v0.5b (distributed with the Linux kernel
+version 2.6.10).  All files include the original copyrights, and the license
+is GPL version 2 (only version 2, as is true for the Linux kernel).  The
+Linux kernel can be downloaded from www.kernel.org.

fs/Kconfig

@@ -169,6 +169,8 @@ source "fs/romfs/Kconfig"
 source "fs/sysv/Kconfig"
 source "fs/ufs/Kconfig"
 
+source "fs/exofs/Kconfig"
+
 endif # MISC_FILESYSTEMS
 
 menuconfig NETWORK_FILESYSTEMS

fs/Makefile

@@ -120,3 +120,4 @@ obj-$(CONFIG_DEBUG_FS)		+= debugfs/
 obj-$(CONFIG_OCFS2_FS)		+= ocfs2/
 obj-$(CONFIG_BTRFS_FS)		+= btrfs/
 obj-$(CONFIG_GFS2_FS)           += gfs2/
+obj-$(CONFIG_EXOFS_FS)          += exofs/

fs/exofs/BUGS

+- Out-of-space may cause a severe problem if the object (and directory entry)
+  were written, but the inode attributes failed. Then if the filesystem was
+  unmounted and mounted the kernel can get into an endless loop doing a readdir.

fs/exofs/Kbuild

+#
+# Kbuild for the EXOFS module
+#
+# Copyright (C) 2008 Panasas Inc.  All rights reserved.
+#
+# Authors:
+#   Boaz Harrosh <bharrosh@panasas.com>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2
+#
+# Kbuild - Gets included from the Kernels Makefile and build system
+#
+
+exofs-y := osd.o inode.o file.o symlink.o namei.o dir.o super.o
+obj-$(CONFIG_EXOFS_FS) += exofs.o

fs/exofs/Kconfig

+config EXOFS_FS
+	tristate "exofs: OSD based file system support"
+	depends on SCSI_OSD_ULD
+	help
+	  EXOFS is a file system that uses an OSD storage device,
+	  as its backing storage.
+
+# Debugging-related stuff
+config EXOFS_DEBUG
+	bool "Enable debugging"
+	depends on EXOFS_FS
+	help
+	  This option enables EXOFS debug prints.

fs/exofs/common.h

+/*
+ * common.h - Common definitions for both Kernel and user-mode utilities
+ *
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com) (avishay@il.ibm.com)
+ * Copyright (C) 2005, 2006
+ * International Business Machines
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <bharrosh@panasas.com>
+ *
+ * Copyrights for code taken from ext2:
+ *     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
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.  Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#ifndef __EXOFS_COM_H__
+#define __EXOFS_COM_H__
+
+#include <linux/types.h>
+
+#include <scsi/osd_attributes.h>
+#include <scsi/osd_initiator.h>
+#include <scsi/osd_sec.h>
+
+/****************************************************************************
+ * Object ID related defines
+ * NOTE: inode# = object ID - EXOFS_OBJ_OFF
+ ****************************************************************************/
+#define EXOFS_MIN_PID   0x10000	/* Smallest partition ID */
+#define EXOFS_OBJ_OFF	0x10000	/* offset for objects */
+#define EXOFS_SUPER_ID	0x10000	/* object ID for on-disk superblock */
+#define EXOFS_ROOT_ID	0x10002	/* object ID for root directory */
+
+/* exofs Application specific page/attribute */
+# define EXOFS_APAGE_FS_DATA	(OSD_APAGE_APP_DEFINED_FIRST + 3)
+# define EXOFS_ATTR_INODE_DATA	1
+
+/*
+ * The maximum number of files we can have is limited by the size of the
+ * inode number.  This is the largest object ID that the file system supports.
+ * Object IDs 0, 1, and 2 are always in use (see above defines).
+ */
+enum {
+	EXOFS_MAX_INO_ID = (sizeof(ino_t) * 8 == 64) ? ULLONG_MAX :
+					(1ULL << (sizeof(ino_t) * 8ULL - 1ULL)),
+	EXOFS_MAX_ID	 = (EXOFS_MAX_INO_ID - 1 - EXOFS_OBJ_OFF),
+};
+
+/****************************************************************************
+ * Misc.
+ ****************************************************************************/
+#define EXOFS_BLKSHIFT	12
+#define EXOFS_BLKSIZE	(1UL << EXOFS_BLKSHIFT)
+
+/****************************************************************************
+ * superblock-related things
+ ****************************************************************************/
+#define EXOFS_SUPER_MAGIC	0x5DF5
+
+/*
+ * The file system control block - stored in an object's data (mainly, the one
+ * with ID EXOFS_SUPER_ID).  This is where the in-memory superblock is stored
+ * on disk.  Right now it just has a magic value, which is basically a sanity
+ * check on our ability to communicate with the object store.
+ */
+struct exofs_fscb {
+	__le64  s_nextid;	/* Highest object ID used */
+	__le32  s_numfiles;	/* Number of files on fs */
+	__le16  s_magic;	/* Magic signature */
+	__le16  s_newfs;	/* Non-zero if this is a new fs */
+};
+
+/****************************************************************************
+ * inode-related things
+ ****************************************************************************/
+#define EXOFS_IDATA		5
+
+/*
+ * The file control block - stored in an object's attributes.  This is where
+ * the in-memory inode is stored on disk.
+ */
+struct exofs_fcb {
+	__le64  i_size;			/* Size of the file */
+	__le16  i_mode;         	/* File mode */
+	__le16  i_links_count;  	/* Links count */
+	__le32  i_uid;          	/* Owner Uid */
+	__le32  i_gid;          	/* Group Id */
+	__le32  i_atime;        	/* Access time */
+	__le32  i_ctime;        	/* Creation time */
+	__le32  i_mtime;        	/* Modification time */
+	__le32  i_flags;        	/* File flags (unused for now)*/
+	__le32  i_generation;   	/* File version (for NFS) */
+	__le32  i_data[EXOFS_IDATA];	/* Short symlink names and device #s */
+};
+
+#define EXOFS_INO_ATTR_SIZE	sizeof(struct exofs_fcb)
+
+/* This is the Attribute the fcb is stored in */
+static const struct __weak osd_attr g_attr_inode_data = ATTR_DEF(
+	EXOFS_APAGE_FS_DATA,
+	EXOFS_ATTR_INODE_DATA,
+	EXOFS_INO_ATTR_SIZE);
+
+/****************************************************************************
+ * dentry-related things
+ ****************************************************************************/
+#define EXOFS_NAME_LEN	255
+
+/*
+ * The on-disk directory entry
+ */
+struct exofs_dir_entry {
+	__le64		inode_no;		/* inode number           */
+	__le16		rec_len;		/* directory entry length */
+	u8		name_len;		/* name length            */
+	u8		file_type;		/* umm...file type        */
+	char		name[EXOFS_NAME_LEN];	/* file name              */
+};
+
+enum {
+	EXOFS_FT_UNKNOWN,
+	EXOFS_FT_REG_FILE,
+	EXOFS_FT_DIR,
+	EXOFS_FT_CHRDEV,
+	EXOFS_FT_BLKDEV,
+	EXOFS_FT_FIFO,
+	EXOFS_FT_SOCK,
+	EXOFS_FT_SYMLINK,
+	EXOFS_FT_MAX
+};
+
+#define EXOFS_DIR_PAD			4
+#define EXOFS_DIR_ROUND			(EXOFS_DIR_PAD - 1)
+#define EXOFS_DIR_REC_LEN(name_len) \
+	(((name_len) + offsetof(struct exofs_dir_entry, name)  + \
+	  EXOFS_DIR_ROUND) & ~EXOFS_DIR_ROUND)
+
+/*************************
+ * function declarations *
+ *************************/
+/* osd.c                 */
+void exofs_make_credential(u8 cred_a[OSD_CAP_LEN],
+			   const struct osd_obj_id *obj);
+
+int exofs_check_ok_resid(struct osd_request *or, u64 *in_resid, u64 *out_resid);
+static inline int exofs_check_ok(struct osd_request *or)
+{
+	return exofs_check_ok_resid(or, NULL, NULL);
+}
+int exofs_sync_op(struct osd_request *or, int timeout, u8 *cred);
+int exofs_async_op(struct osd_request *or,
+	osd_req_done_fn *async_done, void *caller_context, u8 *cred);
+
+int extract_attr_from_req(struct osd_request *or, struct osd_attr *attr);
+
+int osd_req_read_kern(struct osd_request *or,
+	const struct osd_obj_id *obj, u64 offset, void *buff, u64 len);
+
+int osd_req_write_kern(struct osd_request *or,
+	const struct osd_obj_id *obj, u64 offset, void *buff, u64 len);
+
+#endif /*ifndef __EXOFS_COM_H__*/

fs/exofs/dir.c

+/*
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com) (avishay@il.ibm.com)
+ * Copyright (C) 2005, 2006
+ * International Business Machines
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <bharrosh@panasas.com>
+ *
+ * Copyrights for code taken from ext2:
+ *     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
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.  Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include "exofs.h"
+
+static inline unsigned exofs_chunk_size(struct inode *inode)
+{
+	return inode->i_sb->s_blocksize;
+}
+
+static inline void exofs_put_page(struct page *page)
+{
+	kunmap(page);
+	page_cache_release(page);
+}
+
+/* Accesses dir's inode->i_size must be called under inode lock */
+static inline unsigned long dir_pages(struct inode *inode)
+{
+	return (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+}
+
+static unsigned exofs_last_byte(struct inode *inode, unsigned long page_nr)
+{
+	loff_t last_byte = inode->i_size;
+
+	last_byte -= page_nr << PAGE_CACHE_SHIFT;
+	if (last_byte > PAGE_CACHE_SIZE)
+		last_byte = PAGE_CACHE_SIZE;
+	return last_byte;
+}
+
+static int exofs_commit_chunk(struct page *page, loff_t pos, unsigned len)
+{
+	struct address_space *mapping = page->mapping;
+	struct inode *dir = mapping->host;
+	int err = 0;
+
+	dir->i_version++;
+
+	if (!PageUptodate(page))
+		SetPageUptodate(page);
+
+	if (pos+len > dir->i_size) {
+		i_size_write(dir, pos+len);
+		mark_inode_dirty(dir);
+	}
+	set_page_dirty(page);
+
+	if (IS_DIRSYNC(dir))
+		err = write_one_page(page, 1);
+	else
+		unlock_page(page);
+
+	return err;
+}
+
+static void exofs_check_page(struct page *page)
+{
+	struct inode *dir = page->mapping->host;
+	unsigned chunk_size = exofs_chunk_size(dir);
+	char *kaddr = page_address(page);
+	unsigned offs, rec_len;
+	unsigned limit = PAGE_CACHE_SIZE;
+	struct exofs_dir_entry *p;
+	char *error;
+
+	/* if the page is the last one in the directory */
+	if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
+		limit = dir->i_size & ~PAGE_CACHE_MASK;
+		if (limit & (chunk_size - 1))
+			goto Ebadsize;
+		if (!limit)
+			goto out;
+	}
+	for (offs = 0; offs <= limit - EXOFS_DIR_REC_LEN(1); offs += rec_len) {
+		p = (struct exofs_dir_entry *)(kaddr + offs);
+		rec_len = le16_to_cpu(p->rec_len);
+
+		if (rec_len < EXOFS_DIR_REC_LEN(1))
+			goto Eshort;
+		if (rec_len & 3)
+			goto Ealign;
+		if (rec_len < EXOFS_DIR_REC_LEN(p->name_len))
+			goto Enamelen;
+		if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
+			goto Espan;
+	}
+	if (offs != limit)
+		goto Eend;
+out:
+	SetPageChecked(page);
+	return;
+
+Ebadsize:
+	EXOFS_ERR("ERROR [exofs_check_page]: "
+		"size of directory #%lu is not a multiple of chunk size",
+		dir->i_ino
+	);
+	goto fail;
+Eshort:
+	error = "rec_len is smaller than minimal";
+	goto bad_entry;
+Ealign:
+	error = "unaligned directory entry";
+	goto bad_entry;
+Enamelen:
+	error = "rec_len is too small for name_len";
+	goto bad_entry;
+Espan:
+	error = "directory entry across blocks";
+	goto bad_entry;
+bad_entry:
+	EXOFS_ERR(
+		"ERROR [exofs_check_page]: bad entry in directory #%lu: %s - "
+		"offset=%lu, inode=%llu, rec_len=%d, name_len=%d",
+		dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
+		_LLU(le64_to_cpu(p->inode_no)),
+		rec_len, p->name_len);
+	goto fail;
+Eend:
+	p = (struct exofs_dir_entry *)(kaddr + offs);
+	EXOFS_ERR("ERROR [exofs_check_page]: "
+		"entry in directory #%lu spans the page boundary"
+		"offset=%lu, inode=%llu",
+		dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
+		_LLU(le64_to_cpu(p->inode_no)));
+fail:
+	SetPageChecked(page);
+	SetPageError(page);
+}
+
+static struct page *exofs_get_page(struct inode *dir, unsigned long n)
+{
+	struct address_space *mapping = dir->i_mapping;
+	struct page *page = read_mapping_page(mapping, n, NULL);
+
+	if (!IS_ERR(page)) {
+		kmap(page);
+		if (!PageChecked(page))
+			exofs_check_page(page);
+		if (PageError(page))
+			goto fail;
+	}
+	return page;
+
+fail:
+	exofs_put_page(page);
+	return ERR_PTR(-EIO);
+}
+
+static inline int exofs_match(int len, const unsigned char *name,
+					struct exofs_dir_entry *de)
+{
+	if (len != de->name_len)
+		return 0;
+	if (!de->inode_no)
+		return 0;
+	return !memcmp(name, de->name, len);
+}
+
+static inline
+struct exofs_dir_entry *exofs_next_entry(struct exofs_dir_entry *p)
+{
+	return (struct exofs_dir_entry *)((char *)p + le16_to_cpu(p->rec_len));
+}
+
+static inline unsigned
+exofs_validate_entry(char *base, unsigned offset, unsigned mask)
+{
+	struct exofs_dir_entry *de = (struct exofs_dir_entry *)(base + offset);
+	struct exofs_dir_entry *p =
+			(struct exofs_dir_entry *)(base + (offset&mask));
+	while ((char *)p < (char *)de) {
+		if (p->rec_len == 0)
+			break;
+		p = exofs_next_entry(p);
+	}
+	return (char *)p - base;
+}
+
+static unsigned char exofs_filetype_table[EXOFS_FT_MAX] = {
+	[EXOFS_FT_UNKNOWN]	= DT_UNKNOWN,
+	[EXOFS_FT_REG_FILE]	= DT_REG,
+	[EXOFS_FT_DIR]		= DT_DIR,
+	[EXOFS_FT_CHRDEV]	= DT_CHR,
+	[EXOFS_FT_BLKDEV]	= DT_BLK,
+	[EXOFS_FT_FIFO]		= DT_FIFO,
+	[EXOFS_FT_SOCK]		= DT_SOCK,
+	[EXOFS_FT_SYMLINK]	= DT_LNK,
+};
+
+#define S_SHIFT 12
+static unsigned char exofs_type_by_mode[S_IFMT >> S_SHIFT] = {
+	[S_IFREG >> S_SHIFT]	= EXOFS_FT_REG_FILE,
+	[S_IFDIR >> S_SHIFT]	= EXOFS_FT_DIR,
+	[S_IFCHR >> S_SHIFT]	= EXOFS_FT_CHRDEV,
+	[S_IFBLK >> S_SHIFT]	= EXOFS_FT_BLKDEV,
+	[S_IFIFO >> S_SHIFT]	= EXOFS_FT_FIFO,
+	[S_IFSOCK >> S_SHIFT]	= EXOFS_FT_SOCK,
+	[S_IFLNK >> S_SHIFT]	= EXOFS_FT_SYMLINK,
+};
+
+static inline
+void exofs_set_de_type(struct exofs_dir_entry *de, struct inode *inode)
+{
+	mode_t mode = inode->i_mode;
+	de->file_type = exofs_type_by_mode[(mode & S_IFMT) >> S_SHIFT];
+}
+
+static int
+exofs_readdir(struct file *filp, void *dirent, filldir_t filldir)
+{
+	loff_t pos = filp->f_pos;
+	struct inode *inode = filp->f_path.dentry->d_inode;
+	unsigned int offset = pos & ~PAGE_CACHE_MASK;
+	unsigned long n = pos >> PAGE_CACHE_SHIFT;
+	unsigned long npages = dir_pages(inode);
+	unsigned chunk_mask = ~(exofs_chunk_size(inode)-1);
+	unsigned char *types = NULL;
+	int need_revalidate = (filp->f_version != inode->i_version);
+
+	if (pos > inode->i_size - EXOFS_DIR_REC_LEN(1))
+		return 0;
+
+	types = exofs_filetype_table;
+
+	for ( ; n < npages; n++, offset = 0) {
+		char *kaddr, *limit;
+		struct exofs_dir_entry *de;
+		struct page *page = exofs_get_page(inode, n);
+
+		if (IS_ERR(page)) {
+			EXOFS_ERR("ERROR: "
+				   "bad page in #%lu",
+				   inode->i_ino);
+			filp->f_pos += PAGE_CACHE_SIZE - offset;
+			return PTR_ERR(page);
+		}
+		kaddr = page_address(page);
+		if (unlikely(need_revalidate)) {
+			if (offset) {
+				offset = exofs_validate_entry(kaddr, offset,
+								chunk_mask);
+				filp->f_pos = (n<<PAGE_CACHE_SHIFT) + offset;
+			}
+			filp->f_version = inode->i_version;
+			need_revalidate = 0;
+		}
+		de = (struct exofs_dir_entry *)(kaddr + offset);
+		limit = kaddr + exofs_last_byte(inode, n) -
+							EXOFS_DIR_REC_LEN(1);
+		for (; (char *)de <= limit; de = exofs_next_entry(de)) {
+			if (de->rec_len == 0) {
+				EXOFS_ERR("ERROR: "
+					"zero-length directory entry");
+				exofs_put_page(page);
+				return -EIO;
+			}
+			if (de->inode_no) {
+				int over;
+				unsigned char d_type = DT_UNKNOWN;
+
+				if (types && de->file_type < EXOFS_FT_MAX)
+					d_type = types[de->file_type];
+
+				offset = (char *)de - kaddr;
+				over = filldir(dirent, de->name, de->name_len,
+						(n<<PAGE_CACHE_SHIFT) | offset,
+						le64_to_cpu(de->inode_no),
+						d_type);
+				if (over) {
+					exofs_put_page(page);
+					return 0;
+				}
+			}
+			filp->f_pos += le16_to_cpu(de->rec_len);
+		}
+		exofs_put_page(page);
+	}
+
+	return 0;
+}
+
+struct exofs_dir_entry *exofs_find_entry(struct inode *dir,
+			struct dentry *dentry, struct page **res_page)
+{
+	const unsigned char *name = dentry->d_name.name;
+	int namelen = dentry->d_name.len;
+	unsigned reclen = EXOFS_DIR_REC_LEN(namelen);
+	unsigned long start, n;
+	unsigned long npages = dir_pages(dir);
+	struct page *page = NULL;
+	struct exofs_i_info *oi = exofs_i(dir);
+	struct exofs_dir_entry *de;
+
+	if (npages == 0)
+		goto out;
+
+	*res_page = NULL;
+
+	start = oi->i_dir_start_lookup;
+	if (start >= npages)
+		start = 0;
+	n = start;
+	do {
+		char *kaddr;
+		page = exofs_get_page(dir, n);
+		if (!IS_ERR(page)) {
+			kaddr = page_address(page);
+			de = (struct exofs_dir_entry *) kaddr;
+			kaddr += exofs_last_byte(dir, n) - reclen;
+			while ((char *) de <= kaddr) {
+				if (de->rec_len == 0) {
+					EXOFS_ERR(
+						"ERROR: exofs_find_entry: "
+						"zero-length directory entry");
+					exofs_put_page(page);
+					goto out;
+				}
+				if (exofs_match(namelen, name, de))
+					goto found;
+				de = exofs_next_entry(de);
+			}
+			exofs_put_page(page);
+		}
+		if (++n >= npages)
+			n = 0;
+	} while (n != start);
+out:
+	return NULL;
+
+found:
+	*res_page = page;
+	oi->i_dir_start_lookup = n;
+	return de;
+}
+
+struct exofs_dir_entry *exofs_dotdot(struct inode *dir, struct page **p)
+{
+	struct page *page = exofs_get_page(dir, 0);
+	struct exofs_dir_entry *de = NULL;
+
+	if (!IS_ERR(page)) {
+		de = exofs_next_entry(
+				(struct exofs_dir_entry *)page_address(page));
+		*p = page;
+	}
+	return de;
+}
+
+ino_t exofs_parent_ino(struct dentry *child)
+{
+	struct page *page;
+	struct exofs_dir_entry *de;
+	ino_t ino;
+
+	de = exofs_dotdot(child->d_inode, &page);
+	if (!de)
+		return 0;
+
+	ino = le64_to_cpu(de->inode_no);
+	exofs_put_page(page);
+	return ino;
+}
+
+ino_t exofs_inode_by_name(struct inode *dir, struct dentry *dentry)
+{
+	ino_t res = 0;
+	struct exofs_dir_entry *de;
+	struct page *page;
+
+	de = exofs_find_entry(dir, dentry, &page);
+	if (de) {
+		res = le64_to_cpu(de->inode_no);
+		exofs_put_page(page);
+	}
+	return res;
+}
+
+int exofs_set_link(struct inode *dir, struct exofs_dir_entry *de,
+			struct page *page, struct inode *inode)
+{
+	loff_t pos = page_offset(page) +
+			(char *) de - (char *) page_address(page);
+	unsigned len = le16_to_cpu(de->rec_len);
+	int err;
+
+	lock_page(page);
+	err = exofs_write_begin(NULL, page->mapping, pos, len,
+				AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
+	if (err)
+		EXOFS_ERR("exofs_set_link: exofs_write_begin FAILD => %d\n",
+			  err);
+
+	de->inode_no = cpu_to_le64(inode->i_ino);
+	exofs_set_de_type(de, inode);
+	if (likely(!err))
+		err = exofs_commit_chunk(page, pos, len);
+	exofs_put_page(page);
+	dir->i_mtime = dir->i_ctime = CURRENT_TIME;
+	mark_inode_dirty(dir);
+	return err;
+}
+
+int exofs_add_link(struct dentry *dentry, struct inode *inode)
+{
+	struct inode *dir = dentry->d_parent->d_inode;
+	const unsigned char *name = dentry->d_name.name;
+	int namelen = dentry->d_name.len;
+	unsigned chunk_size = exofs_chunk_size(dir);
+	unsigned reclen = EXOFS_DIR_REC_LEN(namelen);
+	unsigned short rec_len, name_len;
+	struct page *page = NULL;
+	struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
+	struct exofs_dir_entry *de;
+	unsigned long npages = dir_pages(dir);
+	unsigned long n;
+	char *kaddr;
+	loff_t pos;
+	int err;
+
+	for (n = 0; n <= npages; n++) {
+		char *dir_end;
+
+		page = exofs_get_page(dir, n);
+		err = PTR_ERR(page);
+		if (IS_ERR(page))
+			goto out;
+		lock_page(page);
+		kaddr = page_address(page);
+		dir_end = kaddr + exofs_last_byte(dir, n);
+		de = (struct exofs_dir_entry *)kaddr;
+		kaddr += PAGE_CACHE_SIZE - reclen;
+		while ((char *)de <= kaddr) {
+			if ((char *)de == dir_end) {
+				name_len = 0;
+				rec_len = chunk_size;
+				de->rec_len = cpu_to_le16(chunk_size);
+				de->inode_no = 0;
+				goto got_it;
+			}
+			if (de->rec_len == 0) {
+				EXOFS_ERR("ERROR: exofs_add_link: "
+					"zero-length directory entry");
+				err = -EIO;
+				goto out_unlock;
+			}
+			err = -EEXIST;
+			if (exofs_match(namelen, name, de))
+				goto out_unlock;
+			name_len = EXOFS_DIR_REC_LEN(de->name_len);
+			rec_len = le16_to_cpu(de->rec_len);
+			if (!de->inode_no && rec_len >= reclen)
+				goto got_it;
+			if (rec_len >= name_len + reclen)
+				goto got_it;
+			de = (struct exofs_dir_entry *) ((char *) de + rec_len);
+		}
+		unlock_page(page);
+		exofs_put_page(page);
+	}
+
+	EXOFS_ERR("exofs_add_link: BAD dentry=%p or inode=%p", dentry, inode);
+	return -EINVAL;
+
+got_it:
+	pos = page_offset(page) +
+		(char *)de - (char *)page_address(page);
+	err = exofs_write_begin(NULL, page->mapping, pos, rec_len, 0,
+							&page, NULL);
+	if (err)
+		goto out_unlock;
+	if (de->inode_no) {
+		struct exofs_dir_entry *de1 =
+			(struct exofs_dir_entry *)((char *)de + name_len);
+		de1->rec_len = cpu_to_le16(rec_len - name_len);
+		de->rec_len = cpu_to_le16(name_len);
+		de = de1;
+	}
+	de->name_len = namelen;
+	memcpy(de->name, name, namelen);
+	de->inode_no = cpu_to_le64(inode->i_ino);
+	exofs_set_de_type(de, inode);
+	err = exofs_commit_chunk(page, pos, rec_len);
+	dir->i_mtime = dir->i_ctime = CURRENT_TIME;
+	mark_inode_dirty(dir);
+	sbi->s_numfiles++;
+
+out_put:
+	exofs_put_page(page);
+out:
+	return err;
+out_unlock:
+	unlock_page(page);
+	goto out_put;
+}
+
+int exofs_delete_entry(struct exofs_dir_entry *dir, struct page *page)
+{
+	struct address_space *mapping = page->mapping;
+	struct inode *inode = mapping->host;
+	struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
+	char *kaddr = page_address(page);
+	unsigned from = ((char *)dir - kaddr) & ~(exofs_chunk_size(inode)-1);
+	unsigned to = ((char *)dir - kaddr) + le16_to_cpu(dir->rec_len);
+	loff_t pos;
+	struct exofs_dir_entry *pde = NULL;
+	struct exofs_dir_entry *de = (struct exofs_dir_entry *) (kaddr + from);
+	int err;
+
+	while (de < dir) {
+		if (de->rec_len == 0) {
+			EXOFS_ERR("ERROR: exofs_delete_entry:"
+				"zero-length directory entry");
+			err = -EIO;
+			goto out;
+		}
+		pde = de;
+		de = exofs_next_entry(de);
+	}
+	if (pde)
+		from = (char *)pde - (char *)page_address(page);
+	pos = page_offset(page) + from;
+	lock_page(page);
+	err = exofs_write_begin(NULL, page->mapping, pos, to - from, 0,
+							&page, NULL);
+	if (err)
+		EXOFS_ERR("exofs_delete_entry: exofs_write_begin FAILD => %d\n",
+			  err);
+	if (pde)
+		pde->rec_len = cpu_to_le16(to - from);
+	dir->inode_no = 0;
+	if (likely(!err))
+		err = exofs_commit_chunk(page, pos, to - from);
+	inode->i_ctime = inode->i_mtime = CURRENT_TIME;
+	mark_inode_dirty(inode);
+	sbi->s_numfiles--;
+out:
+	exofs_put_page(page);
+	return err;
+}
+
+/* kept aligned on 4 bytes */
+#define THIS_DIR ".\0\0"
+#define PARENT_DIR "..\0"
+
+int exofs_make_empty(struct inode *inode, struct inode *parent)
+{
+	struct address_space *mapping = inode->i_mapping;
+	struct page *page = grab_cache_page(mapping, 0);
+	unsigned chunk_size = exofs_chunk_size(inode);
+	struct exofs_dir_entry *de;
+	int err;
+	void *kaddr;
+
+	if (!page)
+		return -ENOMEM;
+
+	err = exofs_write_begin(NULL, page->mapping, 0, chunk_size, 0,
+							&page, NULL);
+	if (err) {
+		unlock_page(page);
+		goto fail;
+	}
+
+	kaddr = kmap_atomic(page, KM_USER0);
+	de = (struct exofs_dir_entry *)kaddr;
+	de->name_len = 1;
+	de->rec_len = cpu_to_le16(EXOFS_DIR_REC_LEN(1));
+	memcpy(de->name, THIS_DIR, sizeof(THIS_DIR));
+	de->inode_no = cpu_to_le64(inode->i_ino);
+	exofs_set_de_type(de, inode);
+
+	de = (struct exofs_dir_entry *)(kaddr + EXOFS_DIR_REC_LEN(1));
+	de->name_len = 2;
+	de->rec_len = cpu_to_le16(chunk_size - EXOFS_DIR_REC_LEN(1));
+	de->inode_no = cpu_to_le64(parent->i_ino);
+	memcpy(de->name, PARENT_DIR, sizeof(PARENT_DIR));
+	exofs_set_de_type(de, inode);
+	kunmap_atomic(page, KM_USER0);
+	err = exofs_commit_chunk(page, 0, chunk_size);
+fail:
+	page_cache_release(page);
+	return err;
+}
+
+int exofs_empty_dir(struct inode *inode)
+{
+	struct page *page = NULL;
+	unsigned long i, npages = dir_pages(inode);
+
+	for (i = 0; i < npages; i++) {
+		char *kaddr;
+		struct exofs_dir_entry *de;
+		page = exofs_get_page(inode, i);
+
+		if (IS_ERR(page))
+			continue;
+
+		kaddr = page_address(page);
+		de = (struct exofs_dir_entry *)kaddr;
+		kaddr += exofs_last_byte(inode, i) - EXOFS_DIR_REC_LEN(1);
+
+		while ((char *)de <= kaddr) {
+			if (de->rec_len == 0) {
+				EXOFS_ERR("ERROR: exofs_empty_dir: "
+					  "zero-length directory entry"
+					  "kaddr=%p, de=%p\n", kaddr, de);
+				goto not_empty;
+			}
+			if (de->inode_no != 0) {
+				/* check for . and .. */
+				if (de->name[0] != '.')
+					goto not_empty;
+				if (de->name_len > 2)
+					goto not_empty;
+				if (de->name_len < 2) {
+					if (le64_to_cpu(de->inode_no) !=
+					    inode->i_ino)
+						goto not_empty;
+				} else if (de->name[1] != '.')
+					goto not_empty;
+			}
+			de = exofs_next_entry(de);
+		}
+		exofs_put_page(page);
+	}
+	return 1;
+
+not_empty:
+	exofs_put_page(page);
+	return 0;
+}
+
+const struct file_operations exofs_dir_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= generic_read_dir,
+	.readdir	= exofs_readdir,
+};

fs/exofs/exofs.h

+/*
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com) (avishay@il.ibm.com)
+ * Copyright (C) 2005, 2006
+ * International Business Machines
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <bharrosh@panasas.com>
+ *
+ * Copyrights for code taken from ext2:
+ *     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
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.  Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <linux/fs.h>
+#include <linux/time.h>
+#include "common.h"
+
+#ifndef __EXOFS_H__
+#define __EXOFS_H__
+
+#define EXOFS_ERR(fmt, a...) printk(KERN_ERR "exofs: " fmt, ##a)
+
+#ifdef CONFIG_EXOFS_DEBUG
+#define EXOFS_DBGMSG(fmt, a...) \
+	printk(KERN_NOTICE "exofs @%s:%d: " fmt, __func__, __LINE__, ##a)
+#else
+#define EXOFS_DBGMSG(fmt, a...) \
+	do { if (0) printk(fmt, ##a); } while (0)
+#endif
+
+/* u64 has problems with printk this will cast it to unsigned long long */
+#define _LLU(x) (unsigned long long)(x)
+
+/*
+ * our extension to the in-memory superblock
+ */
+struct exofs_sb_info {
+	struct osd_dev	*s_dev;			/* returned by get_osd_dev    */
+	osd_id		s_pid;			/* partition ID of file system*/
+	int		s_timeout;		/* timeout for OSD operations */
+	uint64_t	s_nextid;		/* highest object ID used     */
+	uint32_t	s_numfiles;		/* number of files on fs      */
+	spinlock_t	s_next_gen_lock;	/* spinlock for gen # update  */
+	u32		s_next_generation;	/* next gen # to use          */
+	atomic_t	s_curr_pending;		/* number of pending commands */
+	uint8_t		s_cred[OSD_CAP_LEN];	/* all-powerful credential    */
+};
+
+/*
+ * our extension to the in-memory inode
+ */
+struct exofs_i_info {
+	unsigned long  i_flags;            /* various atomic flags            */
+	uint32_t       i_data[EXOFS_IDATA];/*short symlink names and device #s*/
+	uint32_t       i_dir_start_lookup; /* which page to start lookup      */
+	wait_queue_head_t i_wq;            /* wait queue for inode            */
+	uint64_t       i_commit_size;      /* the object's written length     */
+	uint8_t        i_cred[OSD_CAP_LEN];/* all-powerful credential         */
+	struct inode   vfs_inode;          /* normal in-memory inode          */
+};
+
+/*
+ * our inode flags
+ */
+#define OBJ_2BCREATED	0	/* object will be created soon*/
+#define OBJ_CREATED	1	/* object has been created on the osd*/
+
+static inline int obj_2bcreated(struct exofs_i_info *oi)
+{
+	return test_bit(OBJ_2BCREATED, &oi->i_flags);
+}
+
+static inline void set_obj_2bcreated(struct exofs_i_info *oi)
+{
+	set_bit(OBJ_2BCREATED, &oi->i_flags);
+}
+
+static inline int obj_created(struct exofs_i_info *oi)
+{
+	return test_bit(OBJ_CREATED, &oi->i_flags);
+}
+
+static inline void set_obj_created(struct exofs_i_info *oi)
+{
+	set_bit(OBJ_CREATED, &oi->i_flags);
+}
+
+int __exofs_wait_obj_created(struct exofs_i_info *oi);
+static inline int wait_obj_created(struct exofs_i_info *oi)
+{
+	if (likely(obj_created(oi)))
+		return 0;
+
+	return __exofs_wait_obj_created(oi);
+}
+
+/*
+ * get to our inode from the vfs inode
+ */
+static inline struct exofs_i_info *exofs_i(struct inode *inode)
+{
+	return container_of(inode, struct exofs_i_info, vfs_inode);
+}
+
+/*
+ * Maximum count of links to a file
+ */
+#define EXOFS_LINK_MAX           32000
+
+/*************************
+ * function declarations *
+ *************************/
+/* inode.c               */
+void exofs_truncate(struct inode *inode);
+int exofs_setattr(struct dentry *, struct iattr *);
+int exofs_write_begin(struct file *file, struct address_space *mapping,
+		loff_t pos, unsigned len, unsigned flags,
+		struct page **pagep, void **fsdata);
+extern struct inode *exofs_iget(struct super_block *, unsigned long);
+struct inode *exofs_new_inode(struct inode *, int);
+extern int exofs_write_inode(struct inode *, int);
+extern void exofs_delete_inode(struct inode *);
+
+/* dir.c:                */
+int exofs_add_link(struct dentry *, struct inode *);
+ino_t exofs_inode_by_name(struct inode *, struct dentry *);
+int exofs_delete_entry(struct exofs_dir_entry *, struct page *);
+int exofs_make_empty(struct inode *, struct inode *);
+struct exofs_dir_entry *exofs_find_entry(struct inode *, struct dentry *,
+					 struct page **);
+int exofs_empty_dir(struct inode *);
+struct exofs_dir_entry *exofs_dotdot(struct inode *, struct page **);
+ino_t exofs_parent_ino(struct dentry *child);
+int exofs_set_link(struct inode *, struct exofs_dir_entry *, struct page *,
+		    struct inode *);
+
+/*********************
+ * operation vectors *
+ *********************/
+/* dir.c:            */
+extern const struct file_operations exofs_dir_operations;
+
+/* file.c            */
+extern const struct inode_operations exofs_file_inode_operations;
+extern const struct file_operations exofs_file_operations;
+
+/* inode.c           */
+extern const struct address_space_operations exofs_aops;
+
+/* namei.c           */
+extern const struct inode_operations exofs_dir_inode_operations;
+extern const struct inode_operations exofs_special_inode_operations;
+
+/* symlink.c         */
+extern const struct inode_operations exofs_symlink_inode_operations;
+extern const struct inode_operations exofs_fast_symlink_inode_operations;
+
+#endif

fs/exofs/file.c

+/*
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com) (avishay@il.ibm.com)
+ * Copyright (C) 2005, 2006
+ * International Business Machines
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <bharrosh@panasas.com>
+ *
+ * Copyrights for code taken from ext2:
+ *     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
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.  Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <linux/buffer_head.h>
+
+#include "exofs.h"
+
+static int exofs_release_file(struct inode *inode, struct file *filp)
+{
+	return 0;
+}
+
+static int exofs_file_fsync(struct file *filp, struct dentry *dentry,
+			    int datasync)
+{
+	int ret;
+	struct address_space *mapping = filp->f_mapping;
+
+	ret = filemap_write_and_wait(mapping);
+	if (ret)
+		return ret;
+
+	/*Note: file_fsync below also calles sync_blockdev, which is a no-op
+	 *      for exofs, but other then that it does sync_inode and
+	 *      sync_superblock which is what we need here.
+	 */
+	return file_fsync(filp, dentry, datasync);
+}
+
+static int exofs_flush(struct file *file, fl_owner_t id)
+{
+	exofs_file_fsync(file, file->f_path.dentry, 1);
+	/* TODO: Flush the OSD target */
+	return 0;
+}
+
+const struct file_operations exofs_file_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= do_sync_read,
+	.write		= do_sync_write,
+	.aio_read	= generic_file_aio_read,
+	.aio_write	= generic_file_aio_write,
+	.mmap		= generic_file_mmap,
+	.open		= generic_file_open,
+	.release	= exofs_release_file,
+	.fsync		= exofs_file_fsync,
+	.flush		= exofs_flush,
+	.splice_read	= generic_file_splice_read,
+	.splice_write	= generic_file_splice_write,
+};
+
+const struct inode_operations exofs_file_inode_operations = {
+	.truncate	= exofs_truncate,
+	.setattr	= exofs_setattr,
+};

fs/exofs/inode.c

+/*
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com) (avishay@il.ibm.com)
+ * Copyright (C) 2005, 2006
+ * International Business Machines
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <bharrosh@panasas.com>
+ *
+ * Copyrights for code taken from ext2:
+ *     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
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.  Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <linux/writeback.h>
+#include <linux/buffer_head.h>
+#include <scsi/scsi_device.h>
+
+#include "exofs.h"
+
+#ifdef CONFIG_EXOFS_DEBUG
+#  define EXOFS_DEBUG_OBJ_ISIZE 1
+#endif
+
+struct page_collect {
+	struct exofs_sb_info *sbi;
+	struct request_queue *req_q;
+	struct inode *inode;
+	unsigned expected_pages;
+
+	struct bio *bio;
+	unsigned nr_pages;
+	unsigned long length;
+	loff_t pg_first; /* keep 64bit also in 32-arches */
+};
+
+static void _pcol_init(struct page_collect *pcol, unsigned expected_pages,
+		struct inode *inode)
+{
+	struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
+	struct request_queue *req_q = sbi->s_dev->scsi_device->request_queue;
+
+	pcol->sbi = sbi;
+	pcol->req_q = req_q;
+	pcol->inode = inode;
+	pcol->expected_pages = expected_pages;
+
+	pcol->bio = NULL;
+	pcol->nr_pages = 0;
+	pcol->length = 0;
+	pcol->pg_first = -1;
+
+	EXOFS_DBGMSG("_pcol_init ino=0x%lx expected_pages=%u\n", inode->i_ino,
+		     expected_pages);
+}
+
+static void _pcol_reset(struct page_collect *pcol)
+{
+	pcol->expected_pages -= min(pcol->nr_pages, pcol->expected_pages);
+
+	pcol->bio = NULL;
+	pcol->nr_pages = 0;
+	pcol->length = 0;
+	pcol->pg_first = -1;
+	EXOFS_DBGMSG("_pcol_reset ino=0x%lx expected_pages=%u\n",
+		     pcol->inode->i_ino, pcol->expected_pages);
+
+	/* this is probably the end of the loop but in writes
+	 * it might not end here. don't be left with nothing
+	 */
+	if (!pcol->expected_pages)
+		pcol->expected_pages = 128;
+}
+
+static int pcol_try_alloc(struct page_collect *pcol)
+{
+	int pages = min_t(unsigned, pcol->expected_pages, BIO_MAX_PAGES);
+
+	for (; pages; pages >>= 1) {
+		pcol->bio = bio_alloc(GFP_KERNEL, pages);
+		if (likely(pcol->bio))
+			return 0;
+	}
+
+	EXOFS_ERR("Failed to kcalloc expected_pages=%u\n",
+		  pcol->expected_pages);
+	return -ENOMEM;
+}
+
+static void pcol_free(struct page_collect *pcol)
+{
+	bio_put(pcol->bio);
+	pcol->bio = NULL;
+}
+
+static int pcol_add_page(struct page_collect *pcol, struct page *page,
+			 unsigned len)
+{
+	int added_len = bio_add_pc_page(pcol->req_q, pcol->bio, page, len, 0);
+	if (unlikely(len != added_len))
+		return -ENOMEM;
+
+	++pcol->nr_pages;
+	pcol->length += len;
+	return 0;
+}
+
+static int update_read_page(struct page *page, int ret)
+{
+	if (ret == 0) {
+		/* Everything is OK */
+		SetPageUptodate(page);
+		if (PageError(page))
+			ClearPageError(page);
+	} else if (ret == -EFAULT) {
+		/* In this case we were trying to read something that wasn't on
+		 * disk yet - return a page full of zeroes.  This should be OK,
+		 * because the object should be empty (if there was a write
+		 * before this read, the read would be waiting with the page
+		 * locked */
+		clear_highpage(page);
+
+		SetPageUptodate(page);
+		if (PageError(page))
+			ClearPageError(page);
+		ret = 0; /* recovered error */
+		EXOFS_DBGMSG("recovered read error\n");
+	} else /* Error */
+		SetPageError(page);
+
+	return ret;
+}
+
+static void update_write_page(struct page *page, int ret)
+{
+	if (ret) {
+		mapping_set_error(page->mapping, ret);
+		SetPageError(page);
+	}
+	end_page_writeback(page);
+}
+
+/* Called at the end of reads, to optionally unlock pages and update their
+ * status.
+ */
+static int __readpages_done(struct osd_request *or, struct page_collect *pcol,
+			    bool do_unlock)
+{
+	struct bio_vec *bvec;
+	int i;
+	u64 resid;
+	u64 good_bytes;
+	u64 length = 0;
+	int ret = exofs_check_ok_resid(or, &resid, NULL);
+
+	osd_end_request(or);
+
+	if (likely(!ret))
+		good_bytes = pcol->length;
+	else if (!resid)
+		good_bytes = 0;
+	else
+		good_bytes = pcol->length - resid;
+
+	EXOFS_DBGMSG("readpages_done(0x%lx) good_bytes=0x%llx"
+		     " length=0x%lx nr_pages=%u\n",
+		     pcol->inode->i_ino, _LLU(good_bytes), pcol->length,
+		     pcol->nr_pages);
+
+	__bio_for_each_segment(bvec, pcol->bio, i, 0) {
+		struct page *page = bvec->bv_page;
+		struct inode *inode = page->mapping->host;
+		int page_stat;
+
+		if (inode != pcol->inode)
+			continue; /* osd might add more pages at end */
+
+		if (likely(length < good_bytes))
+			page_stat = 0;
+		else
+			page_stat = ret;
+
+		EXOFS_DBGMSG("    readpages_done(0x%lx, 0x%lx) %s\n",
+			  inode->i_ino, page->index,
+			  page_stat ? "bad_bytes" : "good_bytes");
+
+		ret = update_read_page(page, page_stat);
+		if (do_unlock)
+			unlock_page(page);
+		length += bvec->bv_len;
+	}
+
+	pcol_free(pcol);
+	EXOFS_DBGMSG("readpages_done END\n");
+	return ret;
+}
+
+/* callback of async reads */
+static void readpages_done(struct osd_request *or, void *p)
+{
+	struct page_collect *pcol = p;
+
+	__readpages_done(or, pcol, true);
+	atomic_dec(&pcol->sbi->s_curr_pending);
+	kfree(p);
+}
+
+static void _unlock_pcol_pages(struct page_collect *pcol, int ret, int rw)
+{
+	struct bio_vec *bvec;
+	int i;
+
+	__bio_for_each_segment(bvec, pcol->bio, i, 0) {
+		struct page *page = bvec->bv_page;
+
+		if (rw == READ)
+			update_read_page(page, ret);
+		else
+			update_write_page(page, ret);
+
+		unlock_page(page);
+	}
+	pcol_free(pcol);
+}
+
+static int read_exec(struct page_collect *pcol, bool is_sync)
+{
+	struct exofs_i_info *oi = exofs_i(pcol->inode);
+	struct osd_obj_id obj = {pcol->sbi->s_pid,
+					pcol->inode->i_ino + EXOFS_OBJ_OFF};
+	struct osd_request *or = NULL;
+	struct page_collect *pcol_copy = NULL;
+	loff_t i_start = pcol->pg_first << PAGE_CACHE_SHIFT;
+	int ret;
+
+	if (!pcol->bio)
+		return 0;
+
+	/* see comment in _readpage() about sync reads */
+	WARN_ON(is_sync && (pcol->nr_pages != 1));
+
+	or = osd_start_request(pcol->sbi->s_dev, GFP_KERNEL);
+	if (unlikely(!or)) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	osd_req_read(or, &obj, pcol->bio, i_start);
+
+	if (is_sync) {
+		exofs_sync_op(or, pcol->sbi->s_timeout, oi->i_cred);
+		return __readpages_done(or, pcol, false);
+	}
+
+	pcol_copy = kmalloc(sizeof(*pcol_copy), GFP_KERNEL);
+	if (!pcol_copy) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	*pcol_copy = *pcol;
+	ret = exofs_async_op(or, readpages_done, pcol_copy, oi->i_cred);
+	if (unlikely(ret))
+		goto err;
+
+	atomic_inc(&pcol->sbi->s_curr_pending);
+
+	EXOFS_DBGMSG("read_exec obj=0x%llx start=0x%llx length=0x%lx\n",
+		  obj.id, _LLU(i_start), pcol->length);
+
+	/* pages ownership was passed to pcol_copy */
+	_pcol_reset(pcol);
+	return 0;
+
+err:
+	if (!is_sync)
+		_unlock_pcol_pages(pcol, ret, READ);
+	kfree(pcol_copy);
+	if (or)
+		osd_end_request(or);
+	return ret;
+}
+
+/* readpage_strip is called either directly from readpage() or by the VFS from
+ * within read_cache_pages(), to add one more page to be read. It will try to
+ * collect as many contiguous pages as posible. If a discontinuity is
+ * encountered, or it runs out of resources, it will submit the previous segment
+ * and will start a new collection. Eventually caller must submit the last
+ * segment if present.
+ */
+static int readpage_strip(void *data, struct page *page)
+{
+	struct page_collect *pcol = data;
+	struct inode *inode = pcol->inode;
+	struct exofs_i_info *oi = exofs_i(inode);
+	loff_t i_size = i_size_read(inode);
+	pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
+	size_t len;
+	int ret;
+
+	/* FIXME: Just for debugging, will be removed */
+	if (PageUptodate(page))
+		EXOFS_ERR("PageUptodate(0x%lx, 0x%lx)\n", pcol->inode->i_ino,
+			  page->index);
+
+	if (page->index < end_index)
+		len = PAGE_CACHE_SIZE;
+	else if (page->index == end_index)
+		len = i_size & ~PAGE_CACHE_MASK;
+	else
+		len = 0;
+
+	if (!len || !obj_created(oi)) {
+		/* this will be out of bounds, or doesn't exist yet.
+		 * Current page is cleared and the request is split
+		 */
+		clear_highpage(page);
+
+		SetPageUptodate(page);
+		if (PageError(page))
+			ClearPageError(page);
+
+		unlock_page(page);
+		EXOFS_DBGMSG("readpage_strip(0x%lx, 0x%lx) empty page,"
+			     " splitting\n", inode->i_ino, page->index);
+
+		return read_exec(pcol, false);
+	}
+
+try_again:
+
+	if (unlikely(pcol->pg_first == -1)) {
+		pcol->pg_first = page->index;
+	} else if (unlikely((pcol->pg_first + pcol->nr_pages) !=
+		   page->index)) {
+		/* Discontinuity detected, split the request */
+		ret = read_exec(pcol, false);
+		if (unlikely(ret))
+			goto fail;
+		goto try_again;
+	}
+
+	if (!pcol->bio) {
+		ret = pcol_try_alloc(pcol);
+		if (unlikely(ret))
+			goto fail;
+	}
+
+	if (len != PAGE_CACHE_SIZE)
+		zero_user(page, len, PAGE_CACHE_SIZE - len);
+
+	EXOFS_DBGMSG("    readpage_strip(0x%lx, 0x%lx) len=0x%zx\n",
+		     inode->i_ino, page->index, len);
+
+	ret = pcol_add_page(pcol, page, len);
+	if (ret) {
+		EXOFS_DBGMSG("Failed pcol_add_page pages[i]=%p "
+			  "this_len=0x%zx nr_pages=%u length=0x%lx\n",
+			  page, len, pcol->nr_pages, pcol->length);
+
+		/* split the request, and start again with current page */
+		ret = read_exec(pcol, false);
+		if (unlikely(ret))
+			goto fail;
+
+		goto try_again;
+	}
+
+	return 0;
+
+fail:
+	/* SetPageError(page); ??? */
+	unlock_page(page);
+	return ret;
+}
+
+static int exofs_readpages(struct file *file, struct address_space *mapping,
+			   struct list_head *pages, unsigned nr_pages)
+{
+	struct page_collect pcol;
+	int ret;
+
+	_pcol_init(&pcol, nr_pages, mapping->host);
+
+	ret = read_cache_pages(mapping, pages, readpage_strip, &pcol);
+	if (ret) {
+		EXOFS_ERR("read_cache_pages => %d\n", ret);
+		return ret;
+	}
+
+	return read_exec(&pcol, false);
+}
+
+static int _readpage(struct page *page, bool is_sync)
+{
+	struct page_collect pcol;
+	int ret;
+
+	_pcol_init(&pcol, 1, page->mapping->host);
+
+	/* readpage_strip might call read_exec(,async) inside at several places
+	 * but this is safe for is_async=0 since read_exec will not do anything
+	 * when we have a single page.
+	 */
+	ret = readpage_strip(&pcol, page);
+	if (ret) {
+		EXOFS_ERR("_readpage => %d\n", ret);
+		return ret;
+	}
+
+	return read_exec(&pcol, is_sync);
+}
+
+/*
+ * We don't need the file
+ */
+static int exofs_readpage(struct file *file, struct page *page)
+{
+	return _readpage(page, false);
+}
+
+/* Callback for osd_write. All writes are asynchronouse */
+static void writepages_done(struct osd_request *or, void *p)
+{
+	struct page_collect *pcol = p;
+	struct bio_vec *bvec;
+	int i;
+	u64 resid;
+	u64  good_bytes;
+	u64  length = 0;
+
+	int ret = exofs_check_ok_resid(or, NULL, &resid);
+
+	osd_end_request(or);
+	atomic_dec(&pcol->sbi->s_curr_pending);
+
+	if (likely(!ret))
+		good_bytes = pcol->length;
+	else if (!resid)
+		good_bytes = 0;
+	else
+		good_bytes = pcol->length - resid;
+
+	EXOFS_DBGMSG("writepages_done(0x%lx) good_bytes=0x%llx"
+		     " length=0x%lx nr_pages=%u\n",
+		     pcol->inode->i_ino, _LLU(good_bytes), pcol->length,
+		     pcol->nr_pages);
+
+	__bio_for_each_segment(bvec, pcol->bio, i, 0) {
+		struct page *page = bvec->bv_page;
+		struct inode *inode = page->mapping->host;
+		int page_stat;
+
+		if (inode != pcol->inode)
+			continue; /* osd might add more pages to a bio */
+
+		if (likely(length < good_bytes))
+			page_stat = 0;
+		else
+			page_stat = ret;
+
+		update_write_page(page, page_stat);
+		unlock_page(page);
+		EXOFS_DBGMSG("    writepages_done(0x%lx, 0x%lx) status=%d\n",
+			     inode->i_ino, page->index, page_stat);
+
+		length += bvec->bv_len;
+	}
+
+	pcol_free(pcol);
+	kfree(pcol);
+	EXOFS_DBGMSG("writepages_done END\n");
+}
+
+static int write_exec(struct page_collect *pcol)
+{
+	struct exofs_i_info *oi = exofs_i(pcol->inode);
+	struct osd_obj_id obj = {pcol->sbi->s_pid,
+					pcol->inode->i_ino + EXOFS_OBJ_OFF};
+	struct osd_request *or = NULL;
+	struct page_collect *pcol_copy = NULL;
+	loff_t i_start = pcol->pg_first << PAGE_CACHE_SHIFT;
+	int ret;
+
+	if (!pcol->bio)
+		return 0;
+
+	or = osd_start_request(pcol->sbi->s_dev, GFP_KERNEL);
+	if (unlikely(!or)) {
+		EXOFS_ERR("write_exec: Faild to osd_start_request()\n");
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	pcol_copy = kmalloc(sizeof(*pcol_copy), GFP_KERNEL);
+	if (!pcol_copy) {
+		EXOFS_ERR("write_exec: Faild to kmalloc(pcol)\n");
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	*pcol_copy = *pcol;
+
+	osd_req_write(or, &obj, pcol_copy->bio, i_start);
+	ret = exofs_async_op(or, writepages_done, pcol_copy, oi->i_cred);
+	if (unlikely(ret)) {
+		EXOFS_ERR("write_exec: exofs_async_op() Faild\n");
+		goto err;
+	}
+
+	atomic_inc(&pcol->sbi->s_curr_pending);
+	EXOFS_DBGMSG("write_exec(0x%lx, 0x%llx) start=0x%llx length=0x%lx\n",
+		  pcol->inode->i_ino, pcol->pg_first, _LLU(i_start),
+		  pcol->length);
+	/* pages ownership was passed to pcol_copy */
+	_pcol_reset(pcol);
+	return 0;
+
+err:
+	_unlock_pcol_pages(pcol, ret, WRITE);
+	kfree(pcol_copy);
+	if (or)
+		osd_end_request(or);
+	return ret;
+}
+
+/* writepage_strip is called either directly from writepage() or by the VFS from
+ * within write_cache_pages(), to add one more page to be written to storage.
+ * It will try to collect as many contiguous pages as possible. If a
+ * discontinuity is encountered or it runs out of resources it will submit the
+ * previous segment and will start a new collection.
+ * Eventually caller must submit the last segment if present.
+ */
+static int writepage_strip(struct page *page,
+			   struct writeback_control *wbc_unused, void *data)
+{
+	struct page_collect *pcol = data;
+	struct inode *inode = pcol->inode;
+	struct exofs_i_info *oi = exofs_i(inode);
+	loff_t i_size = i_size_read(inode);
+	pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
+	size_t len;
+	int ret;
+
+	BUG_ON(!PageLocked(page));
+
+	ret = wait_obj_created(oi);
+	if (unlikely(ret))
+		goto fail;
+
+	if (page->index < end_index)
+		/* in this case, the page is within the limits of the file */
+		len = PAGE_CACHE_SIZE;
+	else {
+		len = i_size & ~PAGE_CACHE_MASK;
+
+		if (page->index > end_index || !len) {
+			/* in this case, the page is outside the limits
+			 * (truncate in progress)
+			 */
+			ret = write_exec(pcol);
+			if (unlikely(ret))
+				goto fail;
+			if (PageError(page))
+				ClearPageError(page);
+			unlock_page(page);
+			return 0;
+		}
+	}
+
+try_again:
+
+	if (unlikely(pcol->pg_first == -1)) {
+		pcol->pg_first = page->index;
+	} else if (unlikely((pcol->pg_first + pcol->nr_pages) !=
+		   page->index)) {
+		/* Discontinuity detected, split the request */
+		ret = write_exec(pcol);
+		if (unlikely(ret))
+			goto fail;
+		goto try_again;
+	}
+
+	if (!pcol->bio) {
+		ret = pcol_try_alloc(pcol);
+		if (unlikely(ret))
+			goto fail;
+	}
+
+	EXOFS_DBGMSG("    writepage_strip(0x%lx, 0x%lx) len=0x%zx\n",
+		     inode->i_ino, page->index, len);
+
+	ret = pcol_add_page(pcol, page, len);
+	if (unlikely(ret)) {
+		EXOFS_DBGMSG("Failed pcol_add_page "
+			     "nr_pages=%u total_length=0x%lx\n",
+			     pcol->nr_pages, pcol->length);
+
+		/* split the request, next loop will start again */
+		ret = write_exec(pcol);
+		if (unlikely(ret)) {
+			EXOFS_DBGMSG("write_exec faild => %d", ret);
+			goto fail;
+		}
+
+		goto try_again;
+	}
+
+	BUG_ON(PageWriteback(page));
+	set_page_writeback(page);
+
+	return 0;
+
+fail:
+	set_bit(AS_EIO, &page->mapping->flags);
+	unlock_page(page);
+	return ret;
+}
+
+static int exofs_writepages(struct address_space *mapping,
+		       struct writeback_control *wbc)
+{
+	struct page_collect pcol;
+	long start, end, expected_pages;
+	int ret;
+
+	start = wbc->range_start >> PAGE_CACHE_SHIFT;
+	end = (wbc->range_end == LLONG_MAX) ?
+			start + mapping->nrpages :
+			wbc->range_end >> PAGE_CACHE_SHIFT;
+
+	if (start || end)
+		expected_pages = min(end - start + 1, 32L);
+	else
+		expected_pages = mapping->nrpages;
+
+	EXOFS_DBGMSG("inode(0x%lx) wbc->start=0x%llx wbc->end=0x%llx"
+		     " m->nrpages=%lu start=0x%lx end=0x%lx\n",
+		     mapping->host->i_ino, wbc->range_start, wbc->range_end,
+		     mapping->nrpages, start, end);
+
+	_pcol_init(&pcol, expected_pages, mapping->host);
+
+	ret = write_cache_pages(mapping, wbc, writepage_strip, &pcol);
+	if (ret) {
+		EXOFS_ERR("write_cache_pages => %d\n", ret);
+		return ret;
+	}
+
+	return write_exec(&pcol);
+}
+
+static int exofs_writepage(struct page *page, struct writeback_control *wbc)
+{
+	struct page_collect pcol;
+	int ret;
+
+	_pcol_init(&pcol, 1, page->mapping->host);
+
+	ret = writepage_strip(page, NULL, &pcol);
+	if (ret) {
+		EXOFS_ERR("exofs_writepage => %d\n", ret);
+		return ret;
+	}
+
+	return write_exec(&pcol);
+}
+
+int exofs_write_begin(struct file *file, struct address_space *mapping,
+		loff_t pos, unsigned len, unsigned flags,
+		struct page **pagep, void **fsdata)
+{
+	int ret = 0;
+	struct page *page;
+
+	page = *pagep;
+	if (page == NULL) {
+		ret = simple_write_begin(file, mapping, pos, len, flags, pagep,
+					 fsdata);
+		if (ret) {
+			EXOFS_DBGMSG("simple_write_begin faild\n");
+			return ret;
+		}
+
+		page = *pagep;
+	}
+
+	 /* read modify write */
+	if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) {
+		ret = _readpage(page, true);
+		if (ret) {
+			/*SetPageError was done by _readpage. Is it ok?*/
+			unlock_page(page);
+			EXOFS_DBGMSG("__readpage_filler faild\n");
+		}
+	}
+
+	return ret;
+}
+
+static int exofs_write_begin_export(struct file *file,
+		struct address_space *mapping,
+		loff_t pos, unsigned len, unsigned flags,
+		struct page **pagep, void **fsdata)
+{
+	*pagep = NULL;
+
+	return exofs_write_begin(file, mapping, pos, len, flags, pagep,
+					fsdata);
+}
+
+const struct address_space_operations exofs_aops = {
+	.readpage	= exofs_readpage,
+	.readpages	= exofs_readpages,
+	.writepage	= exofs_writepage,
+	.writepages	= exofs_writepages,
+	.write_begin	= exofs_write_begin_export,
+	.write_end	= simple_write_end,
+};
+
+/******************************************************************************
+ * INODE OPERATIONS
+ *****************************************************************************/
+
+/*
+ * Test whether an inode is a fast symlink.
+ */
+static inline int exofs_inode_is_fast_symlink(struct inode *inode)
+{
+	struct exofs_i_info *oi = exofs_i(inode);
+
+	return S_ISLNK(inode->i_mode) && (oi->i_data[0] != 0);
+}
+
+/*
+ * get_block_t - Fill in a buffer_head
+ * An OSD takes care of block allocation so we just fake an allocation by
+ * putting in the inode's sector_t in the buffer_head.
+ * TODO: What about the case of create==0 and @iblock does not exist in the
+ * object?
+ */
+static int exofs_get_block(struct inode *inode, sector_t iblock,
+		    struct buffer_head *bh_result, int create)
+{
+	map_bh(bh_result, inode->i_sb, iblock);
+	return 0;
+}
+
+const struct osd_attr g_attr_logical_length = ATTR_DEF(
+	OSD_APAGE_OBJECT_INFORMATION, OSD_ATTR_OI_LOGICAL_LENGTH, 8);
+
+/*
+ * Truncate a file to the specified size - all we have to do is set the size
+ * attribute.  We make sure the object exists first.
+ */
+void exofs_truncate(struct inode *inode)
+{
+	struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
+	struct exofs_i_info *oi = exofs_i(inode);
+	struct osd_obj_id obj = {sbi->s_pid, inode->i_ino + EXOFS_OBJ_OFF};
+	struct osd_request *or;
+	struct osd_attr attr;
+	loff_t isize = i_size_read(inode);
+	__be64 newsize;
+	int ret;
+
+	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)
+	     || S_ISLNK(inode->i_mode)))
+		return;
+	if (exofs_inode_is_fast_symlink(inode))
+		return;
+	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
+		return;
+	inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+
+	nobh_truncate_page(inode->i_mapping, isize, exofs_get_block);
+
+	or = osd_start_request(sbi->s_dev, GFP_KERNEL);
+	if (unlikely(!or)) {
+		EXOFS_ERR("ERROR: exofs_truncate: osd_start_request failed\n");
+		goto fail;
+	}
+
+	osd_req_set_attributes(or, &obj);
+
+	newsize = cpu_to_be64((u64)isize);
+	attr = g_attr_logical_length;
+	attr.val_ptr = &newsize;
+	osd_req_add_set_attr_list(or, &attr, 1);
+
+	/* if we are about to truncate an object, and it hasn't been
+	 * created yet, wait
+	 */
+	if (unlikely(wait_obj_created(oi)))
+		goto fail;
+
+	ret = exofs_sync_op(or, sbi->s_timeout, oi->i_cred);
+	osd_end_request(or);
+	if (ret)
+		goto fail;
+
+out:
+	mark_inode_dirty(inode);
+	return;
+fail:
+	make_bad_inode(inode);
+	goto out;
+}
+
+/*
+ * Set inode attributes - just call generic functions.
+ */
+int exofs_setattr(struct dentry *dentry, struct iattr *iattr)
+{
+	struct inode *inode = dentry->d_inode;
+	int error;
+
+	error = inode_change_ok(inode, iattr);
+	if (error)
+		return error;
+
+	error = inode_setattr(inode, iattr);
+	return error;
+}
+
+/*
+ * Read an inode from the OSD, and return it as is.  We also return the size
+ * attribute in the 'sanity' argument if we got compiled with debugging turned
+ * on.
+ */
+static int exofs_get_inode(struct super_block *sb, struct exofs_i_info *oi,
+		    struct exofs_fcb *inode, uint64_t *sanity)
+{
+	struct exofs_sb_info *sbi = sb->s_fs_info;
+	struct osd_request *or;
+	struct osd_attr attr;
+	struct osd_obj_id obj = {sbi->s_pid,
+				 oi->vfs_inode.i_ino + EXOFS_OBJ_OFF};
+	int ret;
+
+	exofs_make_credential(oi->i_cred, &obj);
+
+	or = osd_start_request(sbi->s_dev, GFP_KERNEL);
+	if (unlikely(!or)) {
+		EXOFS_ERR("exofs_get_inode: osd_start_request failed.\n");
+		return -ENOMEM;
+	}
+	osd_req_get_attributes(or, &obj);
+
+	/* we need the inode attribute */
+	osd_req_add_get_attr_list(or, &g_attr_inode_data, 1);
+
+#ifdef EXOFS_DEBUG_OBJ_ISIZE
+	/* we get the size attributes to do a sanity check */
+	osd_req_add_get_attr_list(or, &g_attr_logical_length, 1);
+#endif
+
+	ret = exofs_sync_op(or, sbi->s_timeout, oi->i_cred);
+	if (ret)
+		goto out;
+
+	attr = g_attr_inode_data;
+	ret = extract_attr_from_req(or, &attr);
+	if (ret) {
+		EXOFS_ERR("exofs_get_inode: extract_attr_from_req failed\n");
+		goto out;
+	}
+
+	WARN_ON(attr.len != EXOFS_INO_ATTR_SIZE);
+	memcpy(inode, attr.val_ptr, EXOFS_INO_ATTR_SIZE);
+
+#ifdef EXOFS_DEBUG_OBJ_ISIZE
+	attr = g_attr_logical_length;
+	ret = extract_attr_from_req(or, &attr);
+	if (ret) {
+		EXOFS_ERR("ERROR: extract attr from or failed\n");
+		goto out;
+	}
+	*sanity = get_unaligned_be64(attr.val_ptr);
+#endif
+
+out:
+	osd_end_request(or);
+	return ret;
+}
+
+/*
+ * Fill in an inode read from the OSD and set it up for use
+ */
+struct inode *exofs_iget(struct super_block *sb, unsigned long ino)
+{
+	struct exofs_i_info *oi;
+	struct exofs_fcb fcb;
+	struct inode *inode;
+	uint64_t uninitialized_var(sanity);
+	int ret;
+
+	inode = iget_locked(sb, ino);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	if (!(inode->i_state & I_NEW))
+		return inode;
+	oi = exofs_i(inode);
+
+	/* read the inode from the osd */
+	ret = exofs_get_inode(sb, oi, &fcb, &sanity);
+	if (ret)
+		goto bad_inode;
+
+	init_waitqueue_head(&oi->i_wq);
+	set_obj_created(oi);
+
+	/* copy stuff from on-disk struct to in-memory struct */
+	inode->i_mode = le16_to_cpu(fcb.i_mode);
+	inode->i_uid = le32_to_cpu(fcb.i_uid);
+	inode->i_gid = le32_to_cpu(fcb.i_gid);
+	inode->i_nlink = le16_to_cpu(fcb.i_links_count);
+	inode->i_ctime.tv_sec = (signed)le32_to_cpu(fcb.i_ctime);
+	inode->i_atime.tv_sec = (signed)le32_to_cpu(fcb.i_atime);
+	inode->i_mtime.tv_sec = (signed)le32_to_cpu(fcb.i_mtime);
+	inode->i_ctime.tv_nsec =
+		inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = 0;
+	oi->i_commit_size = le64_to_cpu(fcb.i_size);
+	i_size_write(inode, oi->i_commit_size);
+	inode->i_blkbits = EXOFS_BLKSHIFT;
+	inode->i_generation = le32_to_cpu(fcb.i_generation);
+
+#ifdef EXOFS_DEBUG_OBJ_ISIZE
+	if ((inode->i_size != sanity) &&
+		(!exofs_inode_is_fast_symlink(inode))) {
+		EXOFS_ERR("WARNING: Size of object from inode and "
+			  "attributes differ (%lld != %llu)\n",
+			  inode->i_size, _LLU(sanity));
+	}
+#endif
+
+	oi->i_dir_start_lookup = 0;
+
+	if ((inode->i_nlink == 0) && (inode->i_mode == 0)) {
+		ret = -ESTALE;
+		goto bad_inode;
+	}
+
+	if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
+		if (fcb.i_data[0])
+			inode->i_rdev =
+				old_decode_dev(le32_to_cpu(fcb.i_data[0]));
+		else
+			inode->i_rdev =
+				new_decode_dev(le32_to_cpu(fcb.i_data[1]));
+	} else {
+		memcpy(oi->i_data, fcb.i_data, sizeof(fcb.i_data));
+	}
+
+	if (S_ISREG(inode->i_mode)) {
+		inode->i_op = &exofs_file_inode_operations;
+		inode->i_fop = &exofs_file_operations;
+		inode->i_mapping->a_ops = &exofs_aops;
+	} else if (S_ISDIR(inode->i_mode)) {
+		inode->i_op = &exofs_dir_inode_operations;
+		inode->i_fop = &exofs_dir_operations;
+		inode->i_mapping->a_ops = &exofs_aops;
+	} else if (S_ISLNK(inode->i_mode)) {
+		if (exofs_inode_is_fast_symlink(inode))
+			inode->i_op = &exofs_fast_symlink_inode_operations;
+		else {
+			inode->i_op = &exofs_symlink_inode_operations;
+			inode->i_mapping->a_ops = &exofs_aops;
+		}
+	} else {
+		inode->i_op = &exofs_special_inode_operations;
+		if (fcb.i_data[0])
+			init_special_inode(inode, inode->i_mode,
+			   old_decode_dev(le32_to_cpu(fcb.i_data[0])));
+		else
+			init_special_inode(inode, inode->i_mode,
+			   new_decode_dev(le32_to_cpu(fcb.i_data[1])));
+	}
+
+	unlock_new_inode(inode);
+	return inode;
+
+bad_inode:
+	iget_failed(inode);
+	return ERR_PTR(ret);
+}
+
+int __exofs_wait_obj_created(struct exofs_i_info *oi)
+{
+	if (!obj_created(oi)) {
+		BUG_ON(!obj_2bcreated(oi));
+		wait_event(oi->i_wq, obj_created(oi));
+	}
+	return unlikely(is_bad_inode(&oi->vfs_inode)) ? -EIO : 0;
+}
+/*
+ * Callback function from exofs_new_inode().  The important thing is that we
+ * set the obj_created flag so that other methods know that the object exists on
+ * the OSD.
+ */
+static void create_done(struct osd_request *or, void *p)
+{
+	struct inode *inode = p;
+	struct exofs_i_info *oi = exofs_i(inode);
+	struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
+	int ret;
+
+	ret = exofs_check_ok(or);
+	osd_end_request(or);
+	atomic_dec(&sbi->s_curr_pending);
+
+	if (unlikely(ret)) {
+		EXOFS_ERR("object=0x%llx creation faild in pid=0x%llx",
+			  _LLU(sbi->s_pid), _LLU(inode->i_ino + EXOFS_OBJ_OFF));
+		make_bad_inode(inode);
+	} else
+		set_obj_created(oi);
+
+	atomic_dec(&inode->i_count);
+	wake_up(&oi->i_wq);
+}
+
+/*
+ * Set up a new inode and create an object for it on the OSD
+ */
+struct inode *exofs_new_inode(struct inode *dir, int mode)
+{
+	struct super_block *sb;
+	struct inode *inode;
+	struct exofs_i_info *oi;
+	struct exofs_sb_info *sbi;
+	struct osd_request *or;
+	struct osd_obj_id obj;
+	int ret;
+
+	sb = dir->i_sb;
+	inode = new_inode(sb);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+
+	oi = exofs_i(inode);
+
+	init_waitqueue_head(&oi->i_wq);
+	set_obj_2bcreated(oi);
+
+	sbi = sb->s_fs_info;
+
+	sb->s_dirt = 1;
+	inode->i_uid = current->cred->fsuid;
+	if (dir->i_mode & S_ISGID) {
+		inode->i_gid = dir->i_gid;
+		if (S_ISDIR(mode))
+			mode |= S_ISGID;
+	} else {
+		inode->i_gid = current->cred->fsgid;
+	}
+	inode->i_mode = mode;
+
+	inode->i_ino = sbi->s_nextid++;
+	inode->i_blkbits = EXOFS_BLKSHIFT;
+	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
+	oi->i_commit_size = inode->i_size = 0;
+	spin_lock(&sbi->s_next_gen_lock);
+	inode->i_generation = sbi->s_next_generation++;
+	spin_unlock(&sbi->s_next_gen_lock);
+	insert_inode_hash(inode);
+
+	mark_inode_dirty(inode);
+
+	obj.partition = sbi->s_pid;
+	obj.id = inode->i_ino + EXOFS_OBJ_OFF;
+	exofs_make_credential(oi->i_cred, &obj);
+
+	or = osd_start_request(sbi->s_dev, GFP_KERNEL);
+	if (unlikely(!or)) {
+		EXOFS_ERR("exofs_new_inode: osd_start_request failed\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	osd_req_create_object(or, &obj);
+
+	/* increment the refcount so that the inode will still be around when we
+	 * reach the callback
+	 */
+	atomic_inc(&inode->i_count);
+
+	ret = exofs_async_op(or, create_done, inode, oi->i_cred);
+	if (ret) {
+		atomic_dec(&inode->i_count);
+		osd_end_request(or);
+		return ERR_PTR(-EIO);
+	}
+	atomic_inc(&sbi->s_curr_pending);
+
+	return inode;
+}
+
+/*
+ * struct to pass two arguments to update_inode's callback
+ */
+struct updatei_args {
+	struct exofs_sb_info	*sbi;
+	struct exofs_fcb	fcb;
+};
+
+/*
+ * Callback function from exofs_update_inode().
+ */
+static void updatei_done(struct osd_request *or, void *p)
+{
+	struct updatei_args *args = p;
+
+	osd_end_request(or);
+
+	atomic_dec(&args->sbi->s_curr_pending);
+
+	kfree(args);
+}
+
+/*
+ * Write the inode to the OSD.  Just fill up the struct, and set the attribute
+ * synchronously or asynchronously depending on the do_sync flag.
+ */
+static int exofs_update_inode(struct inode *inode, int do_sync)
+{
+	struct exofs_i_info *oi = exofs_i(inode);
+	struct super_block *sb = inode->i_sb;
+	struct exofs_sb_info *sbi = sb->s_fs_info;
+	struct osd_obj_id obj = {sbi->s_pid, inode->i_ino + EXOFS_OBJ_OFF};
+	struct osd_request *or;
+	struct osd_attr attr;
+	struct exofs_fcb *fcb;
+	struct updatei_args *args;
+	int ret;
+
+	args = kzalloc(sizeof(*args), GFP_KERNEL);
+	if (!args)
+		return -ENOMEM;
+
+	fcb = &args->fcb;
+
+	fcb->i_mode = cpu_to_le16(inode->i_mode);
+	fcb->i_uid = cpu_to_le32(inode->i_uid);
+	fcb->i_gid = cpu_to_le32(inode->i_gid);
+	fcb->i_links_count = cpu_to_le16(inode->i_nlink);
+	fcb->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
+	fcb->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
+	fcb->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
+	oi->i_commit_size = i_size_read(inode);
+	fcb->i_size = cpu_to_le64(oi->i_commit_size);
+	fcb->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)) {
+			fcb->i_data[0] =
+				cpu_to_le32(old_encode_dev(inode->i_rdev));
+			fcb->i_data[1] = 0;
+		} else {
+			fcb->i_data[0] = 0;
+			fcb->i_data[1] =
+				cpu_to_le32(new_encode_dev(inode->i_rdev));
+			fcb->i_data[2] = 0;
+		}
+	} else
+		memcpy(fcb->i_data, oi->i_data, sizeof(fcb->i_data));
+
+	or = osd_start_request(sbi->s_dev, GFP_KERNEL);
+	if (unlikely(!or)) {
+		EXOFS_ERR("exofs_update_inode: osd_start_request failed.\n");
+		ret = -ENOMEM;
+		goto free_args;
+	}
+
+	osd_req_set_attributes(or, &obj);
+
+	attr = g_attr_inode_data;
+	attr.val_ptr = fcb;
+	osd_req_add_set_attr_list(or, &attr, 1);
+
+	if (!obj_created(oi)) {
+		EXOFS_DBGMSG("!obj_created\n");
+		BUG_ON(!obj_2bcreated(oi));
+		wait_event(oi->i_wq, obj_created(oi));
+		EXOFS_DBGMSG("wait_event done\n");
+	}
+
+	if (do_sync) {
+		ret = exofs_sync_op(or, sbi->s_timeout, oi->i_cred);
+		osd_end_request(or);
+		goto free_args;
+	} else {
+		args->sbi = sbi;
+
+		ret = exofs_async_op(or, updatei_done, args, oi->i_cred);
+		if (ret) {
+			osd_end_request(or);
+			goto free_args;
+		}
+		atomic_inc(&sbi->s_curr_pending);
+		goto out; /* deallocation in updatei_done */
+	}
+
+free_args:
+	kfree(args);
+out:
+	EXOFS_DBGMSG("ret=>%d\n", ret);
+	return ret;
+}
+
+int exofs_write_inode(struct inode *inode, int wait)
+{
+	return exofs_update_inode(inode, wait);
+}
+
+/*
+ * Callback function from exofs_delete_inode() - don't have much cleaning up to
+ * do.
+ */
+static void delete_done(struct osd_request *or, void *p)
+{
+	struct exofs_sb_info *sbi;
+	osd_end_request(or);
+	sbi = p;
+	atomic_dec(&sbi->s_curr_pending);
+}
+
+/*
+ * Called when the refcount of an inode reaches zero.  We remove the object
+ * from the OSD here.  We make sure the object was created before we try and
+ * delete it.
+ */
+void exofs_delete_inode(struct inode *inode)
+{
+	struct exofs_i_info *oi = exofs_i(inode);
+	struct super_block *sb = inode->i_sb;
+	struct exofs_sb_info *sbi = sb->s_fs_info;
+	struct osd_obj_id obj = {sbi->s_pid, inode->i_ino + EXOFS_OBJ_OFF};
+	struct osd_request *or;
+	int ret;
+
+	truncate_inode_pages(&inode->i_data, 0);
+
+	if (is_bad_inode(inode))
+		goto no_delete;
+
+	mark_inode_dirty(inode);
+	exofs_update_inode(inode, inode_needs_sync(inode));
+
+	inode->i_size = 0;
+	if (inode->i_blocks)
+		exofs_truncate(inode);
+
+	clear_inode(inode);
+
+	or = osd_start_request(sbi->s_dev, GFP_KERNEL);
+	if (unlikely(!or)) {
+		EXOFS_ERR("exofs_delete_inode: osd_start_request failed\n");
+		return;
+	}
+
+	osd_req_remove_object(or, &obj);
+
+	/* if we are deleting an obj that hasn't been created yet, wait */
+	if (!obj_created(oi)) {
+		BUG_ON(!obj_2bcreated(oi));
+		wait_event(oi->i_wq, obj_created(oi));
+	}
+
+	ret = exofs_async_op(or, delete_done, sbi, oi->i_cred);
+	if (ret) {
+		EXOFS_ERR(
+		       "ERROR: @exofs_delete_inode exofs_async_op failed\n");
+		osd_end_request(or);
+		return;
+	}
+	atomic_inc(&sbi->s_curr_pending);
+
+	return;
+
+no_delete:
+	clear_inode(inode);
+}

fs/exofs/namei.c

+/*
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com) (avishay@il.ibm.com)
+ * Copyright (C) 2005, 2006
+ * International Business Machines
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <bharrosh@panasas.com>
+ *
+ * Copyrights for code taken from ext2:
+ *     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
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.  Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include "exofs.h"
+
+static inline int exofs_add_nondir(struct dentry *dentry, struct inode *inode)
+{
+	int err = exofs_add_link(dentry, inode);
+	if (!err) {
+		d_instantiate(dentry, inode);
+		return 0;
+	}
+	inode_dec_link_count(inode);
+	iput(inode);
+	return err;
+}
+
+static struct dentry *exofs_lookup(struct inode *dir, struct dentry *dentry,
+				   struct nameidata *nd)
+{
+	struct inode *inode;
+	ino_t ino;
+
+	if (dentry->d_name.len > EXOFS_NAME_LEN)
+		return ERR_PTR(-ENAMETOOLONG);
+
+	ino = exofs_inode_by_name(dir, dentry);
+	inode = NULL;
+	if (ino) {
+		inode = exofs_iget(dir->i_sb, ino);
+		if (IS_ERR(inode))
+			return ERR_CAST(inode);
+	}
+	return d_splice_alias(inode, dentry);
+}
+
+static int exofs_create(struct inode *dir, struct dentry *dentry, int mode,
+			 struct nameidata *nd)
+{
+	struct inode *inode = exofs_new_inode(dir, mode);
+	int err = PTR_ERR(inode);
+	if (!IS_ERR(inode)) {
+		inode->i_op = &exofs_file_inode_operations;
+		inode->i_fop = &exofs_file_operations;
+		inode->i_mapping->a_ops = &exofs_aops;
+		mark_inode_dirty(inode);
+		err = exofs_add_nondir(dentry, inode);
+	}
+	return err;
+}
+
+static int exofs_mknod(struct inode *dir, struct dentry *dentry, int mode,
+		       dev_t rdev)
+{
+	struct inode *inode;
+	int err;
+
+	if (!new_valid_dev(rdev))
+		return -EINVAL;
+
+	inode = exofs_new_inode(dir, mode);
+	err = PTR_ERR(inode);
+	if (!IS_ERR(inode)) {
+		init_special_inode(inode, inode->i_mode, rdev);
+		mark_inode_dirty(inode);
+		err = exofs_add_nondir(dentry, inode);
+	}
+	return err;
+}
+
+static int exofs_symlink(struct inode *dir, struct dentry *dentry,
+			  const char *symname)
+{
+	struct super_block *sb = dir->i_sb;
+	int err = -ENAMETOOLONG;
+	unsigned l = strlen(symname)+1;
+	struct inode *inode;
+	struct exofs_i_info *oi;
+
+	if (l > sb->s_blocksize)
+		goto out;
+
+	inode = exofs_new_inode(dir, S_IFLNK | S_IRWXUGO);
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out;
+
+	oi = exofs_i(inode);
+	if (l > sizeof(oi->i_data)) {
+		/* slow symlink */
+		inode->i_op = &exofs_symlink_inode_operations;
+		inode->i_mapping->a_ops = &exofs_aops;
+		memset(oi->i_data, 0, sizeof(oi->i_data));
+
+		err = page_symlink(inode, symname, l);
+		if (err)
+			goto out_fail;
+	} else {
+		/* fast symlink */
+		inode->i_op = &exofs_fast_symlink_inode_operations;
+		memcpy(oi->i_data, symname, l);
+		inode->i_size = l-1;
+	}
+	mark_inode_dirty(inode);
+
+	err = exofs_add_nondir(dentry, inode);
+out:
+	return err;
+
+out_fail:
+	inode_dec_link_count(inode);
+	iput(inode);
+	goto out;
+}
+
+static int exofs_link(struct dentry *old_dentry, struct inode *dir,
+		struct dentry *dentry)
+{
+	struct inode *inode = old_dentry->d_inode;
+
+	if (inode->i_nlink >= EXOFS_LINK_MAX)
+		return -EMLINK;
+
+	inode->i_ctime = CURRENT_TIME;
+	inode_inc_link_count(inode);
+	atomic_inc(&inode->i_count);
+
+	return exofs_add_nondir(dentry, inode);
+}
+
+static int exofs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+	struct inode *inode;
+	int err = -EMLINK;
+
+	if (dir->i_nlink >= EXOFS_LINK_MAX)
+		goto out;
+
+	inode_inc_link_count(dir);
+
+	inode = exofs_new_inode(dir, S_IFDIR | mode);
+	err = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out_dir;
+
+	inode->i_op = &exofs_dir_inode_operations;
+	inode->i_fop = &exofs_dir_operations;
+	inode->i_mapping->a_ops = &exofs_aops;
+
+	inode_inc_link_count(inode);
+
+	err = exofs_make_empty(inode, dir);
+	if (err)
+		goto out_fail;
+
+	err = exofs_add_link(dentry, inode);
+	if (err)
+		goto out_fail;
+
+	d_instantiate(dentry, inode);
+out:
+	return err;
+
+out_fail:
+	inode_dec_link_count(inode);
+	inode_dec_link_count(inode);
+	iput(inode);
+out_dir:
+	inode_dec_link_count(dir);
+	goto out;
+}
+
+static int exofs_unlink(struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode = dentry->d_inode;
+	struct exofs_dir_entry *de;
+	struct page *page;
+	int err = -ENOENT;
+
+	de = exofs_find_entry(dir, dentry, &page);
+	if (!de)
+		goto out;
+
+	err = exofs_delete_entry(de, page);
+	if (err)
+		goto out;
+
+	inode->i_ctime = dir->i_ctime;
+	inode_dec_link_count(inode);
+	err = 0;
+out:
+	return err;
+}
+
+static int exofs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode = dentry->d_inode;
+	int err = -ENOTEMPTY;
+
+	if (exofs_empty_dir(inode)) {
+		err = exofs_unlink(dir, dentry);
+		if (!err) {
+			inode->i_size = 0;
+			inode_dec_link_count(inode);
+			inode_dec_link_count(dir);
+		}
+	}
+	return err;
+}
+
+static int exofs_rename(struct inode *old_dir, struct dentry *old_dentry,
+		struct inode *new_dir, struct dentry *new_dentry)
+{
+	struct inode *old_inode = old_dentry->d_inode;
+	struct inode *new_inode = new_dentry->d_inode;
+	struct page *dir_page = NULL;
+	struct exofs_dir_entry *dir_de = NULL;
+	struct page *old_page;
+	struct exofs_dir_entry *old_de;
+	int err = -ENOENT;
+
+	old_de = exofs_find_entry(old_dir, old_dentry, &old_page);
+	if (!old_de)
+		goto out;
+
+	if (S_ISDIR(old_inode->i_mode)) {
+		err = -EIO;
+		dir_de = exofs_dotdot(old_inode, &dir_page);
+		if (!dir_de)
+			goto out_old;
+	}
+
+	if (new_inode) {
+		struct page *new_page;
+		struct exofs_dir_entry *new_de;
+
+		err = -ENOTEMPTY;
+		if (dir_de && !exofs_empty_dir(new_inode))
+			goto out_dir;
+
+		err = -ENOENT;
+		new_de = exofs_find_entry(new_dir, new_dentry, &new_page);
+		if (!new_de)
+			goto out_dir;
+		inode_inc_link_count(old_inode);
+		err = exofs_set_link(new_dir, new_de, new_page, old_inode);
+		new_inode->i_ctime = CURRENT_TIME;
+		if (dir_de)
+			drop_nlink(new_inode);
+		inode_dec_link_count(new_inode);
+		if (err)
+			goto out_dir;
+	} else {
+		if (dir_de) {
+			err = -EMLINK;
+			if (new_dir->i_nlink >= EXOFS_LINK_MAX)
+				goto out_dir;
+		}
+		inode_inc_link_count(old_inode);
+		err = exofs_add_link(new_dentry, old_inode);
+		if (err) {
+			inode_dec_link_count(old_inode);
+			goto out_dir;
+		}
+		if (dir_de)
+			inode_inc_link_count(new_dir);
+	}
+
+	old_inode->i_ctime = CURRENT_TIME;
+
+	exofs_delete_entry(old_de, old_page);
+	inode_dec_link_count(old_inode);
+
+	if (dir_de) {
+		err = exofs_set_link(old_inode, dir_de, dir_page, new_dir);
+		inode_dec_link_count(old_dir);
+		if (err)
+			goto out_dir;
+	}
+	return 0;
+
+
+out_dir:
+	if (dir_de) {
+		kunmap(dir_page);
+		page_cache_release(dir_page);
+	}
+out_old:
+	kunmap(old_page);
+	page_cache_release(old_page);
+out:
+	return err;
+}
+
+const struct inode_operations exofs_dir_inode_operations = {
+	.create 	= exofs_create,
+	.lookup 	= exofs_lookup,
+	.link   	= exofs_link,
+	.unlink 	= exofs_unlink,
+	.symlink	= exofs_symlink,
+	.mkdir  	= exofs_mkdir,
+	.rmdir  	= exofs_rmdir,
+	.mknod  	= exofs_mknod,
+	.rename 	= exofs_rename,
+	.setattr	= exofs_setattr,
+};
+
+const struct inode_operations exofs_special_inode_operations = {
+	.setattr	= exofs_setattr,
+};

fs/exofs/osd.c

+/*
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com) (avishay@il.ibm.com)
+ * Copyright (C) 2005, 2006
+ * International Business Machines
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <bharrosh@panasas.com>
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.  Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <scsi/scsi_device.h>
+#include <scsi/osd_sense.h>
+
+#include "exofs.h"
+
+int exofs_check_ok_resid(struct osd_request *or, u64 *in_resid, u64 *out_resid)
+{
+	struct osd_sense_info osi;
+	int ret = osd_req_decode_sense(or, &osi);
+
+	if (ret) { /* translate to Linux codes */
+		if (osi.additional_code == scsi_invalid_field_in_cdb) {
+			if (osi.cdb_field_offset == OSD_CFO_STARTING_BYTE)
+				ret = -EFAULT;
+			if (osi.cdb_field_offset == OSD_CFO_OBJECT_ID)
+				ret = -ENOENT;
+			else
+				ret = -EINVAL;
+		} else if (osi.additional_code == osd_quota_error)
+			ret = -ENOSPC;
+		else
+			ret = -EIO;
+	}
+
+	/* FIXME: should be include in osd_sense_info */
+	if (in_resid)
+		*in_resid = or->in.req ? or->in.req->data_len : 0;
+
+	if (out_resid)
+		*out_resid = or->out.req ? or->out.req->data_len : 0;
+
+	return ret;
+}
+
+void exofs_make_credential(u8 cred_a[OSD_CAP_LEN], const struct osd_obj_id *obj)
+{
+	osd_sec_init_nosec_doall_caps(cred_a, obj, false, true);
+}
+
+/*
+ * Perform a synchronous OSD operation.
+ */
+int exofs_sync_op(struct osd_request *or, int timeout, uint8_t *credential)
+{
+	int ret;
+
+	or->timeout = timeout;
+	ret = osd_finalize_request(or, 0, credential, NULL);
+	if (ret) {
+		EXOFS_DBGMSG("Faild to osd_finalize_request() => %d\n", ret);
+		return ret;
+	}
+
+	ret = osd_execute_request(or);
+
+	if (ret)
+		EXOFS_DBGMSG("osd_execute_request() => %d\n", ret);
+	/* osd_req_decode_sense(or, ret); */
+	return ret;
+}
+
+/*
+ * Perform an asynchronous OSD operation.
+ */
+int exofs_async_op(struct osd_request *or, osd_req_done_fn *async_done,
+		   void *caller_context, u8 *cred)
+{
+	int ret;
+
+	ret = osd_finalize_request(or, 0, cred, NULL);
+	if (ret) {
+		EXOFS_DBGMSG("Faild to osd_finalize_request() => %d\n", ret);
+		return ret;
+	}
+
+	ret = osd_execute_request_async(or, async_done, caller_context);
+
+	if (ret)
+		EXOFS_DBGMSG("osd_execute_request_async() => %d\n", ret);
+	return ret;
+}
+
+int extract_attr_from_req(struct osd_request *or, struct osd_attr *attr)
+{
+	struct osd_attr cur_attr = {.attr_page = 0}; /* start with zeros */
+	void *iter = NULL;
+	int nelem;
+
+	do {
+		nelem = 1;
+		osd_req_decode_get_attr_list(or, &cur_attr, &nelem, &iter);
+		if ((cur_attr.attr_page == attr->attr_page) &&
+		    (cur_attr.attr_id == attr->attr_id)) {
+			attr->len = cur_attr.len;
+			attr->val_ptr = cur_attr.val_ptr;
+			return 0;
+		}
+	} while (iter);
+
+	return -EIO;
+}
+
+int osd_req_read_kern(struct osd_request *or,
+	const struct osd_obj_id *obj, u64 offset, void* buff, u64 len)
+{
+	struct request_queue *req_q = or->osd_dev->scsi_device->request_queue;
+	struct bio *bio = bio_map_kern(req_q, buff, len, GFP_KERNEL);
+
+	if (!bio)
+		return -ENOMEM;
+
+	osd_req_read(or, obj, bio, offset);
+	return 0;
+}
+
+int osd_req_write_kern(struct osd_request *or,
+	const struct osd_obj_id *obj, u64 offset, void* buff, u64 len)
+{
+	struct request_queue *req_q = or->osd_dev->scsi_device->request_queue;
+	struct bio *bio = bio_map_kern(req_q, buff, len, GFP_KERNEL);
+
+	if (!bio)
+		return -ENOMEM;
+
+	osd_req_write(or, obj, bio, offset);
+	return 0;
+}

fs/exofs/super.c

+/*
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com) (avishay@il.ibm.com)
+ * Copyright (C) 2005, 2006
+ * International Business Machines
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <bharrosh@panasas.com>
+ *
+ * Copyrights for code taken from ext2:
+ *     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
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.  Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <linux/string.h>
+#include <linux/parser.h>
+#include <linux/vfs.h>
+#include <linux/random.h>
+#include <linux/exportfs.h>
+
+#include "exofs.h"
+
+/******************************************************************************
+ * MOUNT OPTIONS
+ *****************************************************************************/
+
+/*
+ * struct to hold what we get from mount options
+ */
+struct exofs_mountopt {
+	const char *dev_name;
+	uint64_t pid;
+	int timeout;
+};
+
+/*
+ * exofs-specific mount-time options.
+ */
+enum { Opt_pid, Opt_to, Opt_mkfs, Opt_format, Opt_err };
+
+/*
+ * Our mount-time options.  These should ideally be 64-bit unsigned, but the
+ * kernel's parsing functions do not currently support that.  32-bit should be
+ * sufficient for most applications now.
+ */
+static match_table_t tokens = {
+	{Opt_pid, "pid=%u"},
+	{Opt_to, "to=%u"},
+	{Opt_err, NULL}
+};
+
+/*
+ * The main option parsing method.  Also makes sure that all of the mandatory
+ * mount options were set.
+ */
+static int parse_options(char *options, struct exofs_mountopt *opts)
+{
+	char *p;
+	substring_t args[MAX_OPT_ARGS];
+	int option;
+	bool s_pid = false;
+
+	EXOFS_DBGMSG("parse_options %s\n", options);
+	/* defaults */
+	memset(opts, 0, sizeof(*opts));
+	opts->timeout = BLK_DEFAULT_SG_TIMEOUT;
+
+	while ((p = strsep(&options, ",")) != NULL) {
+		int token;
+		char str[32];
+
+		if (!*p)
+			continue;
+
+		token = match_token(p, tokens, args);
+		switch (token) {
+		case Opt_pid:
+			if (0 == match_strlcpy(str, &args[0], sizeof(str)))
+				return -EINVAL;
+			opts->pid = simple_strtoull(str, NULL, 0);
+			if (opts->pid < EXOFS_MIN_PID) {
+				EXOFS_ERR("Partition ID must be >= %u",
+					  EXOFS_MIN_PID);
+				return -EINVAL;
+			}
+			s_pid = 1;
+			break;
+		case Opt_to:
+			if (match_int(&args[0], &option))
+				return -EINVAL;
+			if (option <= 0) {
+				EXOFS_ERR("Timout must be > 0");
+				return -EINVAL;
+			}
+			opts->timeout = option * HZ;
+			break;
+		}
+	}
+
+	if (!s_pid) {
+		EXOFS_ERR("Need to specify the following options:\n");
+		EXOFS_ERR("    -o pid=pid_no_to_use\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/******************************************************************************
+ * INODE CACHE
+ *****************************************************************************/
+
+/*
+ * Our inode cache.  Isn't it pretty?
+ */
+static struct kmem_cache *exofs_inode_cachep;
+
+/*
+ * Allocate an inode in the cache
+ */
+static struct inode *exofs_alloc_inode(struct super_block *sb)
+{
+	struct exofs_i_info *oi;
+
+	oi = kmem_cache_alloc(exofs_inode_cachep, GFP_KERNEL);
+	if (!oi)
+		return NULL;
+
+	oi->vfs_inode.i_version = 1;
+	return &oi->vfs_inode;
+}
+
+/*
+ * Remove an inode from the cache
+ */
+static void exofs_destroy_inode(struct inode *inode)
+{
+	kmem_cache_free(exofs_inode_cachep, exofs_i(inode));
+}
+
+/*
+ * Initialize the inode
+ */
+static void exofs_init_once(void *foo)
+{
+	struct exofs_i_info *oi = foo;
+
+	inode_init_once(&oi->vfs_inode);
+}
+
+/*
+ * Create and initialize the inode cache
+ */
+static int init_inodecache(void)
+{
+	exofs_inode_cachep = kmem_cache_create("exofs_inode_cache",
+				sizeof(struct exofs_i_info), 0,
+				SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
+				exofs_init_once);
+	if (exofs_inode_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+/*
+ * Destroy the inode cache
+ */
+static void destroy_inodecache(void)
+{
+	kmem_cache_destroy(exofs_inode_cachep);
+}
+
+/******************************************************************************
+ * SUPERBLOCK FUNCTIONS
+ *****************************************************************************/
+static const struct super_operations exofs_sops;
+static const struct export_operations exofs_export_ops;
+
+/*
+ * Write the superblock to the OSD
+ */
+static void exofs_write_super(struct super_block *sb)
+{
+	struct exofs_sb_info *sbi;
+	struct exofs_fscb *fscb;
+	struct osd_request *or;
+	struct osd_obj_id obj;
+	int ret;
+
+	fscb = kzalloc(sizeof(struct exofs_fscb), GFP_KERNEL);
+	if (!fscb) {
+		EXOFS_ERR("exofs_write_super: memory allocation failed.\n");
+		return;
+	}
+
+	lock_kernel();
+	sbi = sb->s_fs_info;
+	fscb->s_nextid = cpu_to_le64(sbi->s_nextid);
+	fscb->s_numfiles = cpu_to_le32(sbi->s_numfiles);
+	fscb->s_magic = cpu_to_le16(sb->s_magic);
+	fscb->s_newfs = 0;
+
+	or = osd_start_request(sbi->s_dev, GFP_KERNEL);
+	if (unlikely(!or)) {
+		EXOFS_ERR("exofs_write_super: osd_start_request failed.\n");
+		goto out;
+	}
+
+	obj.partition = sbi->s_pid;
+	obj.id = EXOFS_SUPER_ID;
+	ret = osd_req_write_kern(or, &obj, 0, fscb, sizeof(*fscb));
+	if (unlikely(ret)) {
+		EXOFS_ERR("exofs_write_super: osd_req_write_kern failed.\n");
+		goto out;
+	}
+
+	ret = exofs_sync_op(or, sbi->s_timeout, sbi->s_cred);
+	if (unlikely(ret)) {
+		EXOFS_ERR("exofs_write_super: exofs_sync_op failed.\n");
+		goto out;
+	}
+	sb->s_dirt = 0;
+
+out:
+	if (or)
+		osd_end_request(or);
+	unlock_kernel();
+	kfree(fscb);
+}
+
+/*
+ * This function is called when the vfs is freeing the superblock.  We just
+ * need to free our own part.
+ */
+static void exofs_put_super(struct super_block *sb)
+{
+	int num_pend;
+	struct exofs_sb_info *sbi = sb->s_fs_info;
+
+	/* make sure there are no pending commands */
+	for (num_pend = atomic_read(&sbi->s_curr_pending); num_pend > 0;
+	     num_pend = atomic_read(&sbi->s_curr_pending)) {
+		wait_queue_head_t wq;
+		init_waitqueue_head(&wq);
+		wait_event_timeout(wq,
+				  (atomic_read(&sbi->s_curr_pending) == 0),
+				  msecs_to_jiffies(100));
+	}
+
+	osduld_put_device(sbi->s_dev);
+	kfree(sb->s_fs_info);
+	sb->s_fs_info = NULL;
+}
+
+/*
+ * Read the superblock from the OSD and fill in the fields
+ */
+static int exofs_fill_super(struct super_block *sb, void *data, int silent)
+{
+	struct inode *root;
+	struct exofs_mountopt *opts = data;
+	struct exofs_sb_info *sbi;	/*extended info                  */
+	struct exofs_fscb fscb;		/*on-disk superblock info        */
+	struct osd_request *or = NULL;
+	struct osd_obj_id obj;
+	int ret;
+
+	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
+	if (!sbi)
+		return -ENOMEM;
+	sb->s_fs_info = sbi;
+
+	/* use mount options to fill superblock */
+	sbi->s_dev = osduld_path_lookup(opts->dev_name);
+	if (IS_ERR(sbi->s_dev)) {
+		ret = PTR_ERR(sbi->s_dev);
+		sbi->s_dev = NULL;
+		goto free_sbi;
+	}
+
+	sbi->s_pid = opts->pid;
+	sbi->s_timeout = opts->timeout;
+
+	/* fill in some other data by hand */
+	memset(sb->s_id, 0, sizeof(sb->s_id));
+	strcpy(sb->s_id, "exofs");
+	sb->s_blocksize = EXOFS_BLKSIZE;
+	sb->s_blocksize_bits = EXOFS_BLKSHIFT;
+	sb->s_maxbytes = MAX_LFS_FILESIZE;
+	atomic_set(&sbi->s_curr_pending, 0);
+	sb->s_bdev = NULL;
+	sb->s_dev = 0;
+
+	/* read data from on-disk superblock object */
+	obj.partition = sbi->s_pid;
+	obj.id = EXOFS_SUPER_ID;
+	exofs_make_credential(sbi->s_cred, &obj);
+
+	or = osd_start_request(sbi->s_dev, GFP_KERNEL);
+	if (unlikely(!or)) {
+		if (!silent)
+			EXOFS_ERR(
+			       "exofs_fill_super: osd_start_request failed.\n");
+		ret = -ENOMEM;
+		goto free_sbi;
+	}
+	ret = osd_req_read_kern(or, &obj, 0, &fscb, sizeof(fscb));
+	if (unlikely(ret)) {
+		if (!silent)
+			EXOFS_ERR(
+			       "exofs_fill_super: osd_req_read_kern failed.\n");
+		ret = -ENOMEM;
+		goto free_sbi;
+	}
+
+	ret = exofs_sync_op(or, sbi->s_timeout, sbi->s_cred);
+	if (unlikely(ret)) {
+		if (!silent)
+			EXOFS_ERR("exofs_fill_super: exofs_sync_op failed.\n");
+		ret = -EIO;
+		goto free_sbi;
+	}
+
+	sb->s_magic = le16_to_cpu(fscb.s_magic);
+	sbi->s_nextid = le64_to_cpu(fscb.s_nextid);
+	sbi->s_numfiles = le32_to_cpu(fscb.s_numfiles);
+
+	/* make sure what we read from the object store is correct */
+	if (sb->s_magic != EXOFS_SUPER_MAGIC) {
+		if (!silent)
+			EXOFS_ERR("ERROR: Bad magic value\n");
+		ret = -EINVAL;
+		goto free_sbi;
+	}
+
+	/* start generation numbers from a random point */
+	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
+	spin_lock_init(&sbi->s_next_gen_lock);
+
+	/* set up operation vectors */
+	sb->s_op = &exofs_sops;
+	sb->s_export_op = &exofs_export_ops;
+	root = exofs_iget(sb, EXOFS_ROOT_ID - EXOFS_OBJ_OFF);
+	if (IS_ERR(root)) {
+		EXOFS_ERR("ERROR: exofs_iget failed\n");
+		ret = PTR_ERR(root);
+		goto free_sbi;
+	}
+	sb->s_root = d_alloc_root(root);
+	if (!sb->s_root) {
+		iput(root);
+		EXOFS_ERR("ERROR: get root inode failed\n");
+		ret = -ENOMEM;
+		goto free_sbi;
+	}
+
+	if (!S_ISDIR(root->i_mode)) {
+		dput(sb->s_root);
+		sb->s_root = NULL;
+		EXOFS_ERR("ERROR: corrupt root inode (mode = %hd)\n",
+		       root->i_mode);
+		ret = -EINVAL;
+		goto free_sbi;
+	}
+
+	ret = 0;
+out:
+	if (or)
+		osd_end_request(or);
+	return ret;
+
+free_sbi:
+	osduld_put_device(sbi->s_dev); /* NULL safe */
+	kfree(sbi);
+	goto out;
+}
+
+/*
+ * Set up the superblock (calls exofs_fill_super eventually)
+ */
+static int exofs_get_sb(struct file_system_type *type,
+			  int flags, const char *dev_name,
+			  void *data, struct vfsmount *mnt)
+{
+	struct exofs_mountopt opts;
+	int ret;
+
+	ret = parse_options(data, &opts);
+	if (ret)
+		return ret;
+
+	opts.dev_name = dev_name;
+	return get_sb_nodev(type, flags, &opts, exofs_fill_super, mnt);
+}
+
+/*
+ * Return information about the file system state in the buffer.  This is used
+ * by the 'df' command, for example.
+ */
+static int exofs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct super_block *sb = dentry->d_sb;
+	struct exofs_sb_info *sbi = sb->s_fs_info;
+	struct osd_obj_id obj = {sbi->s_pid, 0};
+	struct osd_attr attrs[] = {
+		ATTR_DEF(OSD_APAGE_PARTITION_QUOTAS,
+			OSD_ATTR_PQ_CAPACITY_QUOTA, sizeof(__be64)),
+		ATTR_DEF(OSD_APAGE_PARTITION_INFORMATION,
+			OSD_ATTR_PI_USED_CAPACITY, sizeof(__be64)),
+	};
+	uint64_t capacity = ULLONG_MAX;
+	uint64_t used = ULLONG_MAX;
+	struct osd_request *or;
+	uint8_t cred_a[OSD_CAP_LEN];
+	int ret;
+
+	/* get used/capacity attributes */
+	exofs_make_credential(cred_a, &obj);
+
+	or = osd_start_request(sbi->s_dev, GFP_KERNEL);
+	if (unlikely(!or)) {
+		EXOFS_DBGMSG("exofs_statfs: osd_start_request failed.\n");
+		return -ENOMEM;
+	}
+
+	osd_req_get_attributes(or, &obj);
+	osd_req_add_get_attr_list(or, attrs, ARRAY_SIZE(attrs));
+	ret = exofs_sync_op(or, sbi->s_timeout, cred_a);
+	if (unlikely(ret))
+		goto out;
+
+	ret = extract_attr_from_req(or, &attrs[0]);
+	if (likely(!ret))
+		capacity = get_unaligned_be64(attrs[0].val_ptr);
+	else
+		EXOFS_DBGMSG("exofs_statfs: get capacity failed.\n");
+
+	ret = extract_attr_from_req(or, &attrs[1]);
+	if (likely(!ret))
+		used = get_unaligned_be64(attrs[1].val_ptr);
+	else
+		EXOFS_DBGMSG("exofs_statfs: get used-space failed.\n");
+
+	/* fill in the stats buffer */
+	buf->f_type = EXOFS_SUPER_MAGIC;
+	buf->f_bsize = EXOFS_BLKSIZE;
+	buf->f_blocks = (capacity >> EXOFS_BLKSHIFT);
+	buf->f_bfree = ((capacity - used) >> EXOFS_BLKSHIFT);
+	buf->f_bavail = buf->f_bfree;
+	buf->f_files = sbi->s_numfiles;
+	buf->f_ffree = EXOFS_MAX_ID - sbi->s_numfiles;
+	buf->f_namelen = EXOFS_NAME_LEN;
+
+out:
+	osd_end_request(or);
+	return ret;
+}
+
+static const struct super_operations exofs_sops = {
+	.alloc_inode    = exofs_alloc_inode,
+	.destroy_inode  = exofs_destroy_inode,
+	.write_inode    = exofs_write_inode,
+	.delete_inode   = exofs_delete_inode,
+	.put_super      = exofs_put_super,
+	.write_super    = exofs_write_super,
+	.statfs         = exofs_statfs,
+};
+
+/******************************************************************************
+ * EXPORT OPERATIONS
+ *****************************************************************************/
+
+struct dentry *exofs_get_parent(struct dentry *child)
+{
+	unsigned long ino = exofs_parent_ino(child);
+
+	if (!ino)
+		return NULL;
+
+	return d_obtain_alias(exofs_iget(child->d_inode->i_sb, ino));
+}
+
+static struct inode *exofs_nfs_get_inode(struct super_block *sb,
+		u64 ino, u32 generation)
+{
+	struct inode *inode;
+
+	inode = exofs_iget(sb, ino);
+	if (IS_ERR(inode))
+		return ERR_CAST(inode);
+	if (generation && inode->i_generation != generation) {
+		/* we didn't find the right inode.. */
+		iput(inode);
+		return ERR_PTR(-ESTALE);
+	}
+	return inode;
+}
+
+static struct dentry *exofs_fh_to_dentry(struct super_block *sb,
+				struct fid *fid, int fh_len, int fh_type)
+{
+	return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
+				    exofs_nfs_get_inode);
+}
+
+static struct dentry *exofs_fh_to_parent(struct super_block *sb,
+				struct fid *fid, int fh_len, int fh_type)
+{
+	return generic_fh_to_parent(sb, fid, fh_len, fh_type,
+				    exofs_nfs_get_inode);
+}
+
+static const struct export_operations exofs_export_ops = {
+	.fh_to_dentry = exofs_fh_to_dentry,
+	.fh_to_parent = exofs_fh_to_parent,
+	.get_parent = exofs_get_parent,
+};
+
+/******************************************************************************
+ * INSMOD/RMMOD
+ *****************************************************************************/
+
+/*
+ * struct that describes this file system
+ */
+static struct file_system_type exofs_type = {
+	.owner          = THIS_MODULE,
+	.name           = "exofs",
+	.get_sb         = exofs_get_sb,
+	.kill_sb        = generic_shutdown_super,
+};
+
+static int __init init_exofs(void)
+{
+	int err;
+
+	err = init_inodecache();
+	if (err)
+		goto out;
+
+	err = register_filesystem(&exofs_type);
+	if (err)
+		goto out_d;
+
+	return 0;
+out_d:
+	destroy_inodecache();
+out:
+	return err;
+}
+
+static void __exit exit_exofs(void)
+{
+	unregister_filesystem(&exofs_type);
+	destroy_inodecache();
+}
+
+MODULE_AUTHOR("Avishay Traeger <avishay@gmail.com>");
+MODULE_DESCRIPTION("exofs");
+MODULE_LICENSE("GPL");
+
+module_init(init_exofs)
+module_exit(exit_exofs)

fs/exofs/symlink.c

+/*
+ * Copyright (C) 2005, 2006
+ * Avishay Traeger (avishay@gmail.com) (avishay@il.ibm.com)
+ * Copyright (C) 2005, 2006
+ * International Business Machines
+ * Copyright (C) 2008, 2009
+ * Boaz Harrosh <bharrosh@panasas.com>
+ *
+ * Copyrights for code taken from ext2:
+ *     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
+ *
+ * This file is part of exofs.
+ *
+ * exofs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.  Since it is based on ext2, and the only
+ * valid version of GPL for the Linux kernel is version 2, the only valid
+ * version of GPL for exofs is version 2.
+ *
+ * exofs is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with exofs; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <linux/namei.h>
+
+#include "exofs.h"
+
+static void *exofs_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+	struct exofs_i_info *oi = exofs_i(dentry->d_inode);
+
+	nd_set_link(nd, (char *)oi->i_data);
+	return NULL;
+}
+
+const struct inode_operations exofs_symlink_inode_operations = {
+	.readlink	= generic_readlink,
+	.follow_link	= page_follow_link_light,
+	.put_link	= page_put_link,
+};
+
+const struct inode_operations exofs_fast_symlink_inode_operations = {
+	.readlink	= generic_readlink,
+	.follow_link	= exofs_follow_link,
+};