btrfs: unlock i_mutex after attempting to delete subvolume during send
authorOmar Sandoval <osandov@osandov.com>
Fri, 10 Apr 2015 21:20:40 +0000 (14:20 -0700)
committerChris Mason <clm@fb.com>
Sun, 26 Apr 2015 13:27:02 +0000 (06:27 -0700)
commit909e26dce3f7600f5e293ac0522c28790a0c8c9c
tree253080ceb1292bf9188d93b8bb6555aea725d27d
parentb86054540e4ad7d8df67f3a80658d037a2ce1c02
btrfs: unlock i_mutex after attempting to delete subvolume during send

Whenever the check for a send in progress introduced in commit
521e0546c970 (btrfs: protect snapshots from deleting during send) is
hit, we return without unlocking inode->i_mutex. This is easy to see
with lockdep enabled:

[  +0.000059] ================================================
[  +0.000028] [ BUG: lock held when returning to user space! ]
[  +0.000029] 4.0.0-rc5-00096-g3c435c1 #93 Not tainted
[  +0.000026] ------------------------------------------------
[  +0.000029] btrfs/211 is leaving the kernel with locks still held!
[  +0.000029] 1 lock held by btrfs/211:
[  +0.000023]  #0:  (&type->i_mutex_dir_key){+.+.+.}, at: [<ffffffff8135b8df>] btrfs_ioctl_snap_destroy+0x2df/0x7a0

Make sure we unlock it in the error path.

Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Cc: stable@vger.kernel.org
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Chris Mason <clm@fb.com>
fs/btrfs/ioctl.c