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From:   Olga Kornievskaia <aglo@umich.edu>
Date:   Wed, 9 Dec 2020 12:22:47 -0500
Message-ID: <CAN-5tyFUmQQeQQjHtmetvTN2rcJpf3KwPbhm+6TB_N33auirag@mail.gmail.com>
Subject: Re: [PATCH 0/3] NFS: Disable READ_PLUS by default
To:     Trond Myklebust <trondmy@hammerspace.com>
Cc:     "tigran.mkrtchyan@desy.de" <tigran.mkrtchyan@desy.de>,
        "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
        "Anna.Schumaker@netapp.com" <Anna.Schumaker@netapp.com>,
        "schumaker.anna@gmail.com" <schumaker.anna@gmail.com>
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On Wed, Dec 9, 2020 at 12:12 PM Trond Myklebust <trondmy@hammerspace.com> wrote:
>
> On Wed, 2020-12-09 at 12:07 -0500, Olga Kornievskaia wrote:
> > On Wed, Dec 9, 2020 at 11:59 AM Trond Myklebust
> > <trondmy@hammerspace.com> wrote:
> > >
> > > On Fri, 2020-12-04 at 15:00 -0500, Olga Kornievskaia wrote:
> > > > I object to putting the disable patch in, I think we need to fix
> > > > the
> > > > problem.
> > >
> > > I can't see the problem is fixable in 5.10. There are way too many
> > > changes required, and we're in the middle of the week of the last -
> > > rc
> > > for 5.10. Furthermore, there are no regressions introduced by just
> > > disabling the functionality, because READ_PLUS has only just been
> > > merged in this release cycle.
> > >
> > > I therefore strongly suggest we just send [PATCH 1/3] NFS: Disable
> > > READ_PLUS by default and then fix the rest in 5.11.
> >
> > Sure, but shouldn't there be more ifdefs inside of the xdr code to
> > turn it off completely?
>
> AFAICT, those functions are not called by anything else, so as long as
> the READ_PLUS client functionality is disabled, they should be
> harmless.

Is it benign that in the normal read path sunrpc will be calling a new
function of xdr_realign_pages()? Non readplus code didn't have it.

>
> --
> Trond Myklebust
> Linux NFS client maintainer, Hammerspace
> trond.myklebust@hammerspace.com
>
>