On Sat, Mar 28, 2015 at 11:02 AM, Omar Sandoval <osan...@osandov.com> wrote:
> 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.
>
> Signed-off-by: Omar Sandoval <osan...@osandov.com>
Reviewed-by: Filipe Manana <fdman...@suse.com>
Thanks, should go to stable in my opinion.
> ---
> fs/btrfs/ioctl.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index 74609b9..9fde01f 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -2403,7 +2403,7 @@ static noinline int btrfs_ioctl_snap_destroy(struct
> file *file,
> "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);
> --
> 2.3.4
>
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--
Filipe David Manana,
"Reasonable men adapt themselves to the world.
Unreasonable men adapt the world to themselves.
That's why all progress depends on unreasonable men."
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