> On Feb 10, 2022, at 9:28 AM, J. Bruce Fields <bfields@xxxxxxxxxxxx> wrote:
>
> On Wed, Feb 09, 2022 at 08:52:07PM -0800, Dai Ngo wrote:
>> diff --git a/include/linux/fs.h b/include/linux/fs.h
>> index bbf812ce89a8..726d0005e32f 100644
>> --- a/include/linux/fs.h
>> +++ b/include/linux/fs.h
>> @@ -1068,6 +1068,14 @@ struct lock_manager_operations {
>> int (*lm_change)(struct file_lock *, int, struct list_head *);
>> void (*lm_setup)(struct file_lock *, void **);
>> bool (*lm_breaker_owns_lease)(struct file_lock *);
>> + /*
>> + * This callback function is called after a lock conflict is
>> + * detected. This allows the lock manager of the lock that
>> + * causes the conflict to see if the conflict can be resolved
>> + * somehow. If it can then this callback returns false; the
>> + * conflict was resolved, else returns true.
>> + */
>> + bool (*lm_lock_conflict)(struct file_lock *cfl);
>> };
>
> I don't love that name. The function isn't checking for a lock
> conflict--it'd have to know *what* the lock is conflicting with. It's
> being told whether the lock is still valid.
>
> I'd prefer lm_lock_expired(), with the opposite return values.
Or even lm_lock_is_expired(). I agree that the sense of the
return values should be reversed.
The block comment does not belong in struct lock_manager_operations,
IMO.
Jeff's previous review comment was:
>> @@ -1059,6 +1062,9 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request,
>> list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
>> if (!posix_locks_conflict(request, fl))
>> continue;
>> + if (fl->fl_lmops && fl->fl_lmops->lm_lock_conflict &&
>> + !fl->fl_lmops->lm_lock_conflict(fl))
>> + continue;
>
> The naming of this op is a little misleading. We already know that there
> is a lock confict in this case. The question is whether it's resolvable
> by expiring a tardy client. That said, I don't have a better name to
> suggest at the moment.
>
> A comment about what this function actually tells us would be nice here.
I agree that a comment that spells out the API contract would be
useful. But it doesn't belong in the middle of struct
lock_manager_operations, IMO.
I usually put such information in the block comment that precedes
the individual functions (nfsd4_fl_lock_conflict in this case).
Even so, the patch description has this information already.
Jeff, I think the patch description is adequate for this
purpose -- more information appears later in 3/3. What do you
think?
--
Chuck Lever
