mnt: release locks on error path in do_loopback

do_loopback calls lock_mount(path) and forget to unlock_mount
if clone_mnt or copy_mnt fails.

[   77.661566] ================================================
[   77.662939] [ BUG: lock held when returning to user space! ]
[   77.664104] 3.9.0-rc5+ #17 Not tainted
[   77.664982] ------------------------------------------------
[   77.666488] mount/514 is leaving the kernel with locks still held!
[   77.668027] 2 locks held by mount/514:
[   77.668817]  #0:  (&sb->s_type->i_mutex_key#7){+.+.+.}, at: [<ffffffff811cca22>] lock_mount+0x32/0xe0
[   77.671755]  #1:  (&namespace_sem){+++++.}, at: [<ffffffff811cca3a>] lock_mount+0x4a/0xe0

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 50ca17d3cb45..6c7d31eebba4 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1686,7 +1686,7 @@ static int do_loopback(struct path *path, const char *old_name,
 
         if (IS_ERR(mnt)) {
                 err = PTR_ERR(mnt);
-                goto out;
+                goto out2;
         }
 
         err = graft_tree(mnt, path);