reiserfs: deal with NULL xattr root w/ xattrs disabled

This avoids an Oops in open_xa_root that can occur when deleting a file
with xattrs disabled.  It assumes that the xattr root will be there, and
that is not guaranteed.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c
index cf94964..628075c 100644
--- a/fs/reiserfs/xattr.c
+++ b/fs/reiserfs/xattr.c
@@ -123,7 +123,9 @@
 	mutex_lock_nested(&privroot->d_inode->i_mutex, I_MUTEX_XATTR);
 
 	xaroot = dget(REISERFS_SB(sb)->xattr_root);
-	if (!xaroot->d_inode) {
+	if (!xaroot)
+		xaroot = ERR_PTR(-ENODATA);
+	else if (!xaroot->d_inode) {
 		int err = -ENODATA;
 		if (xattr_may_create(flags))
 			err = xattr_mkdir(privroot->d_inode, xaroot, 0700);