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From:   Olga Kornievskaia <olga.kornievskaia@gmail.com>
Date:   Tue, 9 Mar 2021 15:41:43 -0500
Message-ID: <CAN-5tyFttTHRdnELORJwCER_KPGBNk4W3eLwG0Z=QkwmPQh1UQ@mail.gmail.com>
Subject: Re: [PATCH 1/1] NFSD: fix error handling in callbacks
To:     Trond Myklebust <trondmy@hammerspace.com>
Cc:     "bfields@redhat.com" <bfields@redhat.com>,
        "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
        "chuck.lever@oracle.com" <chuck.lever@oracle.com>
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On Tue, Mar 9, 2021 at 3:22 PM Trond Myklebust <trondmy@hammerspace.com> wrote:
>
> On Tue, 2021-03-09 at 10:37 -0500, J. Bruce Fields wrote:
> > On Tue, Mar 09, 2021 at 09:41:27AM -0500, Olga Kornievskaia wrote:
> > > From: Olga Kornievskaia <kolga@netapp.com>
> > >
> > > When the server tries to do a callback and a client fails it due to
> > > authentication problems, we need the server to set callback down
> > > flag in RENEW so that client can recover.
> >
> > I was looking at this.  It looks to me like this should really be
> > just:
> >
> >         case 1:
> >                 if (task->tk_status)
> >                         nfsd4_mark_cb_down(clp, task->tk_status);
> >
> > If tk_status showed an error, and the ->done method doesn't return 0
> > to
> > tell us it something worth retrying, then the callback failed
> > permanently, so we should mark the callback path down, regardless of
> > the
> > exact error.
>
> I disagree. task->tk_status could be an unhandled NFSv4 error (see
> nfsd4_cb_recall_done()). The client might, for instance, be in the
> process of returning the delegation being recalled. Why should that
> result in the callback channel being marked as down?
>

Are you talking about say the connection going down and server should
just reconnect instead of recovering the callback channel. I assumed
that connection break is something that's not  recoverable by the
callback but perhaps I'm wrong.

> >
> > --b.
> >
> > >
> > > Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
> > > ---
> > >  fs/nfsd/nfs4callback.c | 1 +
> > >  1 file changed, 1 insertion(+)
> > >
> > > diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
> > > index 052be5bf9ef5..7325592b456e 100644
> > > --- a/fs/nfsd/nfs4callback.c
> > > +++ b/fs/nfsd/nfs4callback.c
> > > @@ -1189,6 +1189,7 @@ static void nfsd4_cb_done(struct rpc_task
> > > *task, void *calldata)
> > >                 switch (task->tk_status) {
> > >                 case -EIO:
> > >                 case -ETIMEDOUT:
> > > +               case -EACCES:
> > >                         nfsd4_mark_cb_down(clp, task->tk_status);
> > >                 }
> > >                 break;
> > > --
> > > 2.27.0
> > >
> >
>
> --
> Trond Myklebust
> Linux NFS client maintainer, Hammerspace
> trond.myklebust@hammerspace.com
>
>