Re: [PATCH 1/2] quota: Add mountpath based quota support

Jan Kara
2021-02-12T10:44:09Z

On Fri 12-02-21 11:29:00, Sascha Hauer wrote:
> On Fri, Feb 12, 2021 at 11:05:05AM +0100, Jan Kara wrote:
> > On Fri 12-02-21 09:38:35, Sascha Hauer wrote:
> > > On Thu, Feb 11, 2021 at 03:38:13PM +0000, Christoph Hellwig wrote:
> > > > > + if (!mountpoint)
> > > > > + return -ENODEV;
> > > > > +
> > > > > + ret = user_path_at(AT_FDCWD, mountpoint,
> > > > > + LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT, &mountpath);
> > > >
> > > > user_path_at handles an empty path, although you'll get EFAULT instead.
> > > > Do we care about the -ENODEV here?
> > >
> > > The quotactl manpage documents EFAULT as error code for invalid addr or
> > > special argument, so we really should return -EFAULT here.
> > >
> > > Existing quotactl gets this wrong as well:
> > >
> > > if (!special) {
> > > if (cmds == Q_SYNC)
> > > return quota_sync_all(type);
> > > return -ENODEV;
> > > }
> > >
> > > Should we fix this or is there userspace code that is confused by a changed
> > > return value?
> >
> > I'd leave the original quotactl(2) as is. There's no strong reason to risk
> > breaking some userspace. For the new syscall, I agree we can just
> > standardize the return value, there ENODEV makes even less sense since
> > there's no device in that call.
>
> Ok, will do. Who can pick this series up? Anyone else I need to Cc next
> round?

I guess I can pick up both kernel patches (the manpage patch needs to be
submitted to the manpage list) but please CC linux-api@vger as well so that
interested people are aware of the new syscall.

Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR