On Thu, 2022-02-10 at 16:50 +0000, Chuck Lever III wrote:
>
> > 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?
>
I'd be fine with that.
--
Jeff Layton <jlayton@xxxxxxxxxx>
