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From:   Olga Kornievskaia <olga.kornievskaia@gmail.com>
Date:   Tue, 25 Aug 2020 15:34:51 -0400
Message-ID: <CAN-5tyGdNxe_6=H7YrAkU2xdT02Yr2sZafg-O4aGHf9hM=ifcw@mail.gmail.com>
Subject: Re: [PATCH 1/1] NFSv4.1 handle ERR_DELAY error reclaiming locking
 state on delegation recall
To:     Trond Myklebust <trond.myklebust@hammerspace.com>,
        Anna Schumaker <anna.schumaker@netapp.com>
Cc:     linux-nfs <linux-nfs@vger.kernel.org>
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Any comments on this patch? Thank you.

On Thu, Aug 20, 2020 at 6:50 PM Olga Kornievskaia
<olga.kornievskaia@gmail.com> wrote:
>
> From: Olga Kornievskaia <kolga@netapp.com>
>
> A client should be able to handle getting an ERR_DELAY error
> while doing a LOCK call to reclaim state due to delegation being
> recalled. This is a transient error that can happen due to server
> moving its volumes and invalidating its file location cache and
> upon reference to it during the LOCK call needing to do an
> expensive lookup (leading to an ERR_DELAY error on a PUTFH).
>
> Signed-off-by: Olga Kornievskaia <kolga@netapp.com>
> ---
>  fs/nfs/nfs4proc.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index dbd01548335b..4a6cfb497103 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -7298,7 +7298,12 @@ int nfs4_lock_delegation_recall(struct file_lock *fl, struct nfs4_state *state,
>         err = nfs4_set_lock_state(state, fl);
>         if (err != 0)
>                 return err;
> -       err = _nfs4_do_setlk(state, F_SETLK, fl, NFS_LOCK_NEW);
> +       do {
> +               err = _nfs4_do_setlk(state, F_SETLK, fl, NFS_LOCK_NEW);
> +               if (err != -NFS4ERR_DELAY)
> +                       break;
> +               ssleep(1);
> +       } while (err == -NFS4ERR_DELAY);
>         return nfs4_handle_delegation_recall_error(server, state, stateid, fl, err);
>  }
>
> --
> 2.18.1
>