This is a note to let you know that I've just added the patch titled btrfs: unlock i_mutex after attempting to delete subvolume during send to the 4.0-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: btrfs-unlock-i_mutex-after-attempting-to-delete-subvolume-during-send.patch and it can be found in the queue-4.0 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 909e26dce3f7600f5e293ac0522c28790a0c8c9c Mon Sep 17 00:00:00 2001 From: Omar Sandoval <osandov@xxxxxxxxxxx> Date: Fri, 10 Apr 2015 14:20:40 -0700 Subject: btrfs: unlock i_mutex after attempting to delete subvolume during send From: Omar Sandoval <osandov@xxxxxxxxxxx> commit 909e26dce3f7600f5e293ac0522c28790a0c8c9c upstream. 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@xxxxxxxx> Reviewed-by: David Sterba <dsterba@xxxxxxx> Signed-off-by: Omar Sandoval <osandov@xxxxxxxxxxx> Signed-off-by: Chris Mason <clm@xxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/btrfs/ioctl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -2403,7 +2403,7 @@ static noinline int btrfs_ioctl_snap_des "Attempt to delete subvolume %llu during send", dest->root_key.objectid); err = -EPERM; - goto out_dput; + goto out_unlock_inode; } d_invalidate(dentry); @@ -2498,6 +2498,7 @@ out_up_write: root_flags & ~BTRFS_ROOT_SUBVOL_DEAD); spin_unlock(&dest->root_item_lock); } +out_unlock_inode: mutex_unlock(&inode->i_mutex); if (!err) { shrink_dcache_sb(root->fs_info->sb); Patches currently in stable-queue which might be from osandov@xxxxxxxxxxx are queue-4.0/btrfs-unlock-i_mutex-after-attempting-to-delete-subvolume-during-send.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html