On Wed, Mar 19, 2014 at 04:45:49PM -0400, Jeff Layton wrote:
> A leftover lock on the list is surely a sign of a problem of some sort,
> but it's not necessarily a reason to panic the box. Instead, just log a
> warning with some info about the lock, and then delete it like we would
> any other lock.
>
> In the event that the filesystem declares a ->lock f_op, we may end up
> leaking something, but that's generally preferable to an immediate
> panic.
Acked-by: J. Bruce Fields <bfields@xxxxxxxxxx>
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> fs/locks.c | 24 ++++++++++++++++++------
> 1 file changed, 18 insertions(+), 6 deletions(-)
>
> diff --git a/fs/locks.c b/fs/locks.c
> index 6084f5a32e9c..dd309333afc9 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -2281,16 +2281,28 @@ void locks_remove_flock(struct file *filp)
>
> while ((fl = *before) != NULL) {
> if (fl->fl_file == filp) {
> - if (IS_FLOCK(fl)) {
> - locks_delete_lock(before);
> - continue;
> - }
> if (IS_LEASE(fl)) {
> lease_modify(before, F_UNLCK);
> continue;
> }
> - /* What? */
> - BUG();
> +
> + /*
> + * There's a leftover lock on the list of a type that
> + * we didn't expect to see. Most likely a classic
> + * POSIX lock that ended up not getting released
> + * properly, or that raced onto the list somehow. Log
> + * some info about it and then just remove it from
> + * the list.
> + */
> + WARN(!IS_FLOCK(fl),
> + "leftover lock: dev=%u:%u ino=%lu type=%hhd flags=0x%x start=%lld end=%lld\n",
> + MAJOR(inode->i_sb->s_dev),
> + MINOR(inode->i_sb->s_dev), inode->i_ino,
> + fl->fl_type, fl->fl_flags,
> + fl->fl_start, fl->fl_end);
> +
> + locks_delete_lock(before);
> + continue;
> }
> before = &fl->fl_next;
> }
> --
> 1.8.5.3
>
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