reiserfs: suppress lockdep warning

We're getting lockdep warnings due to a post-2.6.21-rc7 bugfix.

The xattr_sem can never be taken in the manner described. Internal inodes
are protected by I_PRIVATE.  Add the appropriate annotation.

Cc: <stable@kernel.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/reiserfs/xattr.c

@@ -68,7 +68,7 @@ static struct dentry *get_xa_root(struct super_block *sb, int flags)
 	if (!privroot)
 		return ERR_PTR(-ENODATA);
 
-	mutex_lock(&privroot->d_inode->i_mutex);
+	mutex_lock_nested(&privroot->d_inode->i_mutex, I_MUTEX_XATTR);
 	if (REISERFS_SB(sb)->xattr_root) {
 		xaroot = dget(REISERFS_SB(sb)->xattr_root);
 		goto out;