NTFS: Release 2.1.7 - Enable NFS exporting of mounted NTFS volumes.

- Implement ntfs_get_parent() and ntfs_get_dentry() as the NTFS specific
  export operations ->get_parent() and ->get_dentry() respectively.

Documentation/filesystems/ntfs.txt

@@ -272,6 +272,8 @@ ChangeLog
 
 Note, a technical ChangeLog aimed at kernel hackers is in fs/ntfs/ChangeLog.
 
+2.1.7:
+	- Enable NFS exporting of mounted NTFS volumes.
 2.1.6:
 	- Fix minor bug in handling of compressed directories that fixes the
 	  erroneous "du" and "stat" output people reported.

fs/ntfs/ChangeLog

 ToDo:
 	- Find and fix bugs.
-	- Enable NFS exporting of NTFS.
 	- Implement aops->set_page_dirty() in order to take control of buffer
 	  dirtying. Not having it means if page_has_buffers(), all buffers
 	  will be dirtied with the page. And if not they won't be. That is
@@ -20,10 +19,19 @@ ToDo:
 	  sufficient for synchronisation here. We then just need to make sure
 	  ntfs_readpage/writepage/truncate interoperate properly with us.
 
-2.1.7 - WIP
+2.1.7 - Enable NFS exporting of mounted NTFS volumes.
 
 	- Set i_generation in the VFS inode from the seq_no of the NTFS inode.
 	- Make ntfs_lookup() NFS export safe, i.e. use d_splice_alias(), etc.
+	- Implement ->get_dentry() in fs/ntfs/namei.c::ntfs_get_dentry() as the
+	  default doesn't allow inode number 0 which is a valid inode on NTFS
+	  and even if it did allow that it uses iget() instead of ntfs_iget()
+	  which makes it useless for us.
+	- Implement ->get_parent() in fs/ntfs/namei.c::ntfs_get_parent() as the
+	  default just returns -EACCES which is not very useful.
+	- Define export operations (->s_export_op) for NTFS (ntfs_export_ops)
+	  and set them up in the super block at mount time (super.c) this
+	  allows mounted NTFS volumes to be exported via NFS.
 
 2.1.6 - Fix minor bug in handling of compressed directories.
 

fs/ntfs/Makefile

@@ -5,7 +5,7 @@ obj-$(CONFIG_NTFS_FS) += ntfs.o
 ntfs-objs := aops.o attrib.o compress.o debug.o dir.o file.o inode.o mft.o \
 	     mst.o namei.o super.o sysctl.o time.o unistr.o upcase.o
 
-EXTRA_CFLAGS = -DNTFS_VERSION=\"2.1.7-WIP\"
+EXTRA_CFLAGS = -DNTFS_VERSION=\"2.1.7\"
 
 ifeq ($(CONFIG_NTFS_DEBUG),y)
 EXTRA_CFLAGS += -DDEBUG

fs/ntfs/dir.c

 /**
  * dir.c - NTFS kernel directory operations. Part of the Linux-NTFS project.
  *
- * Copyright (c) 2001-2003 Anton Altaparmakov
+ * Copyright (c) 2001-2004 Anton Altaparmakov
  * Copyright (c) 2002 Richard Russon
  *
  * This program/include file is free software; you can redistribute it and/or
@@ -200,7 +200,8 @@ MFT_REF ntfs_lookup_inode_by_name(ntfs_inode *dir_ni, const uchar_t *uname,
 						"and if that doesn't find any "
 						"errors please report you saw "
 						"this message to "
-						"linux-ntfs-dev@lists.sf.net.");
+						"linux-ntfs-dev@lists."
+						"sourceforge.net.");
 				goto dir_err_out;
 			}
 
@@ -457,7 +458,8 @@ MFT_REF ntfs_lookup_inode_by_name(ntfs_inode *dir_ni, const uchar_t *uname,
 						"and if that doesn't find any "
 						"errors please report you saw "
 						"this message to "
-						"linux-ntfs-dev@lists.sf.net.");
+						"linux-ntfs-dev@lists."
+						"sourceforge.net.");
 				ntfs_unmap_page(page);
 				goto dir_err_out;
 			}

fs/ntfs/inode.c

@@ -196,7 +196,7 @@ struct inode *ntfs_iget(struct super_block *sb, unsigned long mft_no)
 	}
 	/*
 	 * There is no point in keeping bad inodes around if the failure was
-	 * due to ENOMEM. We want to be able to retry again layer.
+	 * due to ENOMEM. We want to be able to retry again later.
 	 */
 	if (err == -ENOMEM) {
 		iput(vi);
@@ -1137,7 +1137,8 @@ static int ntfs_read_locked_attr_inode(struct inode *base_vi, struct inode *vi)
 					"the attribute is resident (mft_no "
 					"0x%lx, type 0x%x, name_len %i). "
 					"Please report you saw this message "
-					"to linux-ntfs-dev@lists.sf.net",
+					"to linux-ntfs-dev@lists."
+					"sourceforge.net",
 					vi->i_ino, ni->type, ni->name_len);
 			goto unm_err_out;
 		}
@@ -1157,8 +1158,9 @@ static int ntfs_read_locked_attr_inode(struct inode *base_vi, struct inode *vi)
 						"type 0x%x, name_len %i). "
 						"Please report you saw this "
 						"message to linux-ntfs-dev@"
-						"lists.sf.net", vi->i_ino,
-						ni->type, ni->name_len);
+						"lists.sourceforge.net",
+						vi->i_ino, ni->type,
+						ni->name_len);
 				goto unm_err_out;
 			}
 			NInoSetCompressed(ni);
@@ -1169,7 +1171,8 @@ static int ntfs_read_locked_attr_inode(struct inode *base_vi, struct inode *vi)
 						"(mft_no 0x%lx, type 0x%x, "
 						"name_len %i). Please report "
 						"you saw this message to "
-						"linux-ntfs-dev@lists.sf.net",
+						"linux-ntfs-dev@lists."
+						"sourceforge.net",
 						vi->i_ino, ni->type,
 						ni->name_len);
 				goto unm_err_out;
@@ -1224,8 +1227,9 @@ static int ntfs_read_locked_attr_inode(struct inode *base_vi, struct inode *vi)
 						"type 0x%x, name_len %i). "
 						"Please report you saw this "
 						"message to linux-ntfs-dev@"
-						"lists.sf.net", vi->i_ino,
-						ni->type, ni->name_len);
+						"lists.sourceforge.net",
+						vi->i_ino, ni->type,
+						ni->name_len);
 				goto unm_err_out;
 			}
 			NInoSetEncrypted(ni);
@@ -1238,8 +1242,9 @@ static int ntfs_read_locked_attr_inode(struct inode *base_vi, struct inode *vi)
 						"type 0x%x, name_len %i). "
 						"Please report you saw this "
 						"message to linux-ntfs-dev@"
-						"lists.sf.net", vi->i_ino,
-						ni->type, ni->name_len);
+						"lists.sourceforge.net",
+						vi->i_ino, ni->type,
+						ni->name_len);
 				goto unm_err_out;
 			}
 			NInoSetSparse(ni);
@@ -1541,7 +1546,8 @@ void ntfs_read_inode_mount(struct inode *vi)
 						"of $MFT is not in the base "
 						"mft record. Please report "
 						"you saw this message to "
-						"linux-ntfs-dev@lists.sf.net");
+						"linux-ntfs-dev@lists."
+						"sourceforge.net");
 				goto put_err_out;
 			} else {
 				/* Sequence numbers must match. */
@@ -1662,7 +1668,8 @@ void ntfs_read_inode_mount(struct inode *vi)
 						"Run chkdsk and if no errors "
 						"are found, please report you "
 						"saw this message to "
-						"linux-ntfs-dev@lists.sf.net");
+						"linux-ntfs-dev@lists."
+						"sourceforge.net");
 				put_attr_search_ctx(ctx);
 				/* Revert to the safe super operations. */
 				sb->s_op = &ntfs_mount_sops;

fs/ntfs/namei.c

@@ -331,10 +331,133 @@ static struct dentry *ntfs_lookup(struct inode *dir_ino, struct dentry *dent, st
    }
 }
 
-/*
+/**
  * Inode operations for directories.
  */
 struct inode_operations ntfs_dir_inode_ops = {
 	.lookup	= ntfs_lookup,	/* VFS: Lookup directory. */
 };
 
+/**
+ * ntfs_get_parent - find the dentry of the parent of a given directory dentry
+ * @child_dent:		dentry of the directory whose parent directory to find
+ *
+ * Find the dentry for the parent directory of the directory specified by the
+ * dentry @child_dent.  This function is called from
+ * fs/exportfs/expfs.c::find_exported_dentry() which in turn is called from the
+ * default ->decode_fh() which is export_decode_fh() in the same file.
+ *
+ * The code is based on the ext3 ->get_parent() implementation found in
+ * fs/ext3/namei.c::ext3_get_parent().
+ *
+ * Note: ntfs_get_parent() is called with @child_dent->d_inode->i_sem down.
+ *
+ * Return the dentry of the parent directory on success or the error code on
+ * error (IS_ERR() is true).
+ */
+struct dentry *ntfs_get_parent(struct dentry *child_dent)
+{
+	struct inode *vi = child_dent->d_inode;
+	ntfs_inode *ni = NTFS_I(vi);
+	MFT_RECORD *mrec;
+	attr_search_context *ctx;
+	ATTR_RECORD *attr;
+	FILE_NAME_ATTR *fn;
+	struct inode *parent_vi;
+	struct dentry *parent_dent;
+	unsigned long parent_ino;
+
+	ntfs_debug("Entering for inode %lu.", vi->i_ino);
+	/* Get the mft record of the inode belonging to the child dentry. */
+	mrec = map_mft_record(ni);
+	if (unlikely(IS_ERR(mrec)))
+		return (struct dentry *)mrec;
+	/* Find the first file name attribute in the mft record. */
+	ctx = get_attr_search_ctx(ni, mrec);
+	if (unlikely(!ctx)) {
+		unmap_mft_record(ni);
+		return ERR_PTR(-ENOMEM);
+	}
+try_next:
+	if (unlikely(!lookup_attr(AT_FILE_NAME, NULL, 0, IGNORE_CASE, 0,
+			NULL, 0, ctx))) {
+		put_attr_search_ctx(ctx);
+		unmap_mft_record(ni);
+		return ERR_PTR(-ENOENT);
+	}
+	attr = ctx->attr;
+	if (unlikely(attr->non_resident))
+		goto try_next;
+	fn = (FILE_NAME_ATTR *)((u8 *)attr +
+			le16_to_cpu(attr->data.resident.value_offset));
+	if (unlikely((u8 *)fn + le32_to_cpu(attr->data.resident.value_length) >=
+			(u8*)attr + le32_to_cpu(attr->length)))
+		goto try_next;
+	/* Get the inode number of the parent directory. */
+	parent_ino = MREF_LE(fn->parent_directory);
+	/* Release the search context and the mft record of the child. */
+	put_attr_search_ctx(ctx);
+	unmap_mft_record(ni);
+	/* Get the inode of the parent directory. */
+	parent_vi = ntfs_iget(vi->i_sb, parent_ino);
+	if (unlikely(IS_ERR(parent_vi) || is_bad_inode(parent_vi))) {
+		if (!IS_ERR(parent_vi))
+			iput(parent_vi);
+		return ERR_PTR(-EACCES);
+	}
+	/* Finally get a dentry for the parent directory and return it. */
+	parent_dent = d_alloc_anon(parent_vi);
+	if (unlikely(!parent_dent)) {
+		iput(parent_vi);
+		return ERR_PTR(-ENOMEM);
+	}
+	ntfs_debug("Done for inode %lu.", vi->i_ino);
+	return parent_dent;
+}
+
+/**
+ * ntfs_get_dentry - find a dentry for the inode from a file handle sub-fragment
+ * @sb:		super block identifying the mounted ntfs volume
+ * @fh:		the file handle sub-fragment
+ *
+ * Find a dentry for the inode given a file handle sub-fragment.  This function
+ * is called from fs/exportfs/expfs.c::find_exported_dentry() which in turn is
+ * called from the default ->decode_fh() which is export_decode_fh() in the
+ * same file.  The code is closely based on the default ->get_dentry() helper
+ * fs/exportfs/expfs.c::get_object().
+ *
+ * The @fh contains two 32-bit unsigned values, the first one is the inode
+ * number and the second one is the inode generation.
+ *
+ * Return the dentry on success or the error code on error (IS_ERR() is true).
+ */
+struct dentry *ntfs_get_dentry(struct super_block *sb, void *fh)
+{
+	struct inode *vi;
+	struct dentry *dent;
+	unsigned long ino = ((u32 *)fh)[0];
+	u32 gen = ((u32 *)fh)[1];
+
+	ntfs_debug("Entering for inode %lu, generation %u.", ino, gen);
+	vi = ntfs_iget(sb, ino);
+	if (unlikely(IS_ERR(vi)))
+		return (struct dentry *)vi;
+	if (unlikely(is_bad_inode(vi) || vi->i_generation != gen)) {
+		/* We didn't find the right inode. */
+		ntfs_debug("Inode %lu, bad count: %d %d or version %u %u.",
+				vi->i_ino, vi->i_nlink,
+				atomic_read(&vi->i_count), vi->i_generation,
+				gen);
+		iput(vi);
+		return ERR_PTR(-ESTALE);
+	}
+	/* Now find a dentry.  If possible, get a well-connected one. */
+	dent = d_alloc_anon(vi);
+	if (unlikely(!dent)) {
+		iput(vi);
+		return ERR_PTR(-ENOMEM);
+	}
+	ntfs_debug("Done for inode %lu, generation %u.", ino, gen);
+	return dent;
+}
+

fs/ntfs/super.c

 /*
  * super.c - NTFS kernel super block handling. Part of the Linux-NTFS project.
  *
- * Copyright (c) 2001-2003 Anton Altaparmakov
+ * Copyright (c) 2001-2004 Anton Altaparmakov
  * Copyright (c) 2001,2002 Richard Russon
  *
  * This program/include file is free software; you can redistribute it and/or
@@ -1338,6 +1338,40 @@ struct super_operations ntfs_sops = {
 	.show_options	= ntfs_show_options, /* Show mount options in proc. */
 };
 
+
+/**
+ * Declarations for NTFS specific export operations (fs/ntfs/namei.c).
+ */
+extern struct dentry *ntfs_get_parent(struct dentry *child_dent);
+extern struct dentry *ntfs_get_dentry(struct super_block *sb, void *fh);
+
+/**
+ * Export operations allowing NFS exporting of mounted NTFS partitions.
+ *
+ * We use the default ->decode_fh() and ->encode_fh() for now.  Note that they
+ * use 32 bits to store the inode number which is an unsigned long so on 64-bit
+ * architectures is usually 64 bits so it would all fail horribly on huge
+ * volumes.  I guess we need to define our own encode and decode fh functions
+ * that store 64-bit inode numbers at some point but for now we will ignore the
+ * problem...
+ *
+ * We also use the default ->get_name() helper (used by ->decode_fh() via
+ * fs/exportfs/expfs.c::find_exported_dentry()) as that is completely fs
+ * independent.
+ *
+ * The default ->get_parent() just returns -EACCES so we have to provide our
+ * own and the default ->get_dentry() is incompatible with NTFS due to not
+ * allowing the inode number 0 which is used in NTFS for the system file $MFT
+ * and due to using iget() whereas NTFS needs ntfs_iget().
+ */
+static struct export_operations ntfs_export_ops = {
+	.get_parent	= ntfs_get_parent,	/* Find the parent of a given
+						   directory. */
+	.get_dentry	= ntfs_get_dentry,	/* Find a dentry for the inode
+						   given a file handle
+						   sub-fragment. */
+};
+
 /**
  * ntfs_fill_super - mount an ntfs files system
  * @sb:		super block of ntfs file system to mount
@@ -1544,6 +1578,7 @@ static int ntfs_fill_super(struct super_block *sb, void *opt, const int silent)
 			default_upcase = NULL;
 		}
 		up(&ntfs_lock);
+		sb->s_export_op = &ntfs_export_ops;
 		return 0;
 	}
 	ntfs_error(sb, "Failed to allocate root directory.");
@@ -1788,13 +1823,13 @@ static void __exit exit_ntfs_fs(void)
 		printk(KERN_CRIT "NTFS: This causes memory to leak! There is "
 				"probably a BUG in the driver! Please report "
 				"you saw this message to "
-				"linux-ntfs-dev@lists.sf.net\n");
+				"linux-ntfs-dev@lists.sourceforge.net\n");
 	/* Unregister the ntfs sysctls. */
 	ntfs_sysctl(0);
 }
 
 MODULE_AUTHOR("Anton Altaparmakov <aia21@cantab.net>");
-MODULE_DESCRIPTION("NTFS 1.2/3.x driver - Copyright (c) 2001-2003 Anton Altaparmakov");
+MODULE_DESCRIPTION("NTFS 1.2/3.x driver - Copyright (c) 2001-2004 Anton Altaparmakov");
 MODULE_LICENSE("GPL");
 #ifdef DEBUG
 MODULE_PARM(debug_msgs, "i");