[PATCH] Allow file systems to manually d_move() inside of ->rename()

Some file systems want to manually d_move() the dentries involved in a
rename.  We can do this by making use of the FS_ODD_RENAME flag if we just
have nfs_rename() unconditionally do the d_move().  While there, we rename
the flag to be more descriptive.

OCFS2 uses this to protect that part of the rename operation with a cluster
lock.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>

fs/namei.c

@@ -2370,7 +2370,8 @@ static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry,
 		dput(new_dentry);
 	}
 	if (!error)
-		d_move(old_dentry,new_dentry);
+		if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE))
+			d_move(old_dentry,new_dentry);
 	return error;
 }
 
@@ -2393,8 +2394,7 @@ static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry,
 	else
 		error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry);
 	if (!error) {
-		/* The following d_move() should become unconditional */
-		if (!(old_dir->i_sb->s_type->fs_flags & FS_ODD_RENAME))
+		if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE))
 			d_move(old_dentry, new_dentry);
 	}
 	if (target)

fs/nfs/dir.c

@@ -1669,8 +1669,7 @@ static int nfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 	if (rehash)
 		d_rehash(rehash);
 	if (!error) {
-		if (!S_ISDIR(old_inode->i_mode))
-			d_move(old_dentry, new_dentry);
+		d_move(old_dentry, new_dentry);
 		nfs_renew_times(new_dentry);
 		nfs_set_verifier(new_dentry, nfs_save_change_attribute(new_dir));
 	}

fs/nfs/super.c

@@ -71,15 +71,15 @@ static struct file_system_type nfs_fs_type = {
 	.name		= "nfs",
 	.get_sb		= nfs_get_sb,
 	.kill_sb	= nfs_kill_super,
-	.fs_flags	= FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 };
 
 struct file_system_type nfs_xdev_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "nfs",
 	.get_sb		= nfs_xdev_get_sb,
 	.kill_sb	= nfs_kill_super,
-	.fs_flags	= FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 };
 
 static struct super_operations nfs_sops = {
@@ -107,23 +107,23 @@ static struct file_system_type nfs4_fs_type = {
 	.name		= "nfs4",
 	.get_sb		= nfs4_get_sb,
 	.kill_sb	= nfs4_kill_super,
-	.fs_flags	= FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 };
 
 struct file_system_type nfs4_xdev_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "nfs4",
 	.get_sb		= nfs4_xdev_get_sb,
 	.kill_sb	= nfs4_kill_super,
-	.fs_flags	= FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 };
 
 struct file_system_type nfs4_referral_fs_type = {
 	.owner		= THIS_MODULE,
 	.name		= "nfs4",
 	.get_sb		= nfs4_referral_get_sb,
 	.kill_sb	= nfs4_kill_super,
-	.fs_flags	= FS_ODD_RENAME|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
+	.fs_flags	= FS_RENAME_DOES_D_MOVE|FS_REVAL_DOT|FS_BINARY_MOUNTDATA,
 };
 
 static struct super_operations nfs4_sops = {

include/linux/fs.h

@@ -92,9 +92,10 @@ extern int dir_notify_enable;
 #define FS_REQUIRES_DEV 1 
 #define FS_BINARY_MOUNTDATA 2
 #define FS_REVAL_DOT	16384	/* Check the paths ".", ".." for staleness */
-#define FS_ODD_RENAME	32768	/* Temporary stuff; will go away as soon
-				  * as nfs_rename() will be cleaned up
-				  */
+#define FS_RENAME_DOES_D_MOVE	32768	/* FS will handle d_move()
+					 * during rename() internally.
+					 */
+
 /*
  * These are the fs-independent mount-flags: up to 32 flags are supported
  */