Re: nfsd changes for 2.6.37

Christoph Hellwig
2010-10-27T15:20:36Z

On Wed, Oct 27, 2010 at 11:16:46AM -0400, J. Bruce Fields wrote:
> On Wed, Oct 27, 2010 at 10:59:29AM -0400, Christoph Hellwig wrote:
> > On Wed, Oct 27, 2010 at 10:55:39AM -0400, J. Bruce Fields wrote:
> > > Hm, two problems:
> > > - We introduce the possibility of fcntl(fd, F_SETLEASE, F_UNLCK)
> > > failing with ENOMEM.
> >
> > splitt ->setlease into ->add_least and ->delete_lease. No need to pass
> > in a structure for the later. No need to return one either.
>
> Sounds fine to me.
>
> >
> > > - fasync_helper(.,.,1,.) sleeps. Argh.
> >
> > That's not new..
>
> So we could do
>
> unlock_flocks();
> error = fasync_helper(fd, filp, 1, &fl->fl_fasync);
> lock_flocks();
>
> and say, hey, we didn't introduce any new bug there. But....
>
> I don't know, maybe add a version of fasync_add_entry() that takes a
> preallocated fasync_struct??

Or just convert the lock to a sleeping mutex. Now that we have adaptive
spinning the horrible behaviour that Willy saw years ago might not be
that bad any more. That'll need some benchmarking, though.