Re: [PATCH v2] fs: handle shrinker registration failure in sget_userns

Michal Hocko
2017-11-23T15:34:22Z

On Thu 23-11-17 16:02:11, Michal Hocko wrote:
> On Thu 23-11-17 14:55:40, Al Viro wrote:
> > On Thu, Nov 23, 2017 at 03:35:37PM +0100, Michal Hocko wrote:
> > > Hopefully less screwed version. But as I've said I am not really
> > > familiar with the code and do not feel competent to change it so please
> > > be very careful here. I've moved the shrinker registration to
> > > alloc_super which turned out to be simpler.
> >
> > I don't get it. Why the hell do we need all that PITA in the first place?
> > Just make sget_userns() end with
> > if (unlikely(regsiter_shrinker(&s->s_shrink) != 0)) {
> > deactivate_locked_super(s);
> > s = ERR_PTR(-ENOMEM);
> > }
> > return s;
> > and be done with that. All there is to it...
>
> Who is going to unregister that shrinker on other failure paths?

Scratch that. I've mixed destroy_unused_super with
deactivate_locked_super. Go with whatever works...
--
Michal Hocko
SUSE Labs