[PATCH] cleanups and bug fix in do_loopback()

 - check_mnt() on the source of binding should've been unconditional
   from the very beginning.  My fault - as far I could've trace it,
   that's an old thinko made back in 2001.  Kudos to Miklos for spotting
   it...

   Fixed.

 - code cleaned up.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/namespace.c

@@ -661,15 +661,18 @@ static int do_loopback(struct nameidata *nd, char *old_name, int recurse)
 
 	down_write(&current->namespace->sem);
 	err = -EINVAL;
-	if (check_mnt(nd->mnt) && (!recurse || check_mnt(old_nd.mnt))) {
+	if (!check_mnt(nd->mnt) || !check_mnt(old_nd.mnt))
+		goto out;
+
 	err = -ENOMEM;
 	if (recurse)
 		mnt = copy_tree(old_nd.mnt, old_nd.dentry);
 	else
 		mnt = clone_mnt(old_nd.mnt, old_nd.dentry);
-	}
 
-	if (mnt) {
+	if (!mnt)
+		goto out;
+
 	/* stop bind mounts from expiring */
 	spin_lock(&vfsmount_lock);
 	list_del_init(&mnt->mnt_expire);
@@ -682,8 +685,8 @@ static int do_loopback(struct nameidata *nd, char *old_name, int recurse)
 		spin_unlock(&vfsmount_lock);
 	} else
 		mntput(mnt);
-	}
 
+out:
 	up_write(&current->namespace->sem);
 	path_release(&old_nd);
 	return err;