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In-Reply-To: <d4224806db02d9e0597177c467a7ea942c99dba7.camel@hammerspace.com>
From:   Olga Kornievskaia <aglo@umich.edu>
Date:   Thu, 12 Sep 2019 11:01:44 -0400
Message-ID: <CAN-5tyEHirLkH=snFQGLkOTWtpCNYowS9Zpf_nejoS8+dt+wwg@mail.gmail.com>
Subject: Re: [PATCH 8/9] NFSv4: Handle NFS4ERR_OLD_STATEID in CLOSE/OPEN_DOWNGRADE
To:     Trond Myklebust <trondmy@hammerspace.com>
Cc:     "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>,
        "Anna.Schumaker@netapp.com" <Anna.Schumaker@netapp.com>
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On Wed, Sep 11, 2019 at 4:56 PM Trond Myklebust <trondmy@hammerspace.com> wrote:
>
> Hi Olga
>
> On Wed, 2019-09-11 at 16:13 -0400, Olga Kornievskaia wrote:
> > Hi Trond,
> >
> > This patch is causing me "problem" (can be seen using generic/323).
> > This test creates 100 processes that each want to open the same file,
> > then close it. Each open gets a stateid with an increasing seqid (the
> > last received by the client is stateid seqid=100). With the patch,
> > upon close I see 1st CLOSE use stateid seqid=1 which ends up failing
> > with ERR_OLD_STATEID and retried until stateid seqid=100 (which was
> > the current id). Reverting the patch give back sending the CLOSE with
> > seqid=100. While nothing failing, I don't think the client's behavior
> > is correct.
>
> Does the following work for you?

Yes that fixes the stateid usage.

>
> Cheers
>   Trond
>
> 8<---------------------------------------------
> From 859f6c0f468785770c6e87ae4f62294415018e89 Mon Sep 17 00:00:00 2001
> From: Trond Myklebust <trond.myklebust@hammerspace.com>
> Date: Tue, 3 Sep 2019 17:37:19 -0400
> Subject: [PATCH v2] NFSv4: Handle NFS4ERR_OLD_STATEID in CLOSE/OPEN_DOWNGRADE
>
> If a CLOSE or OPEN_DOWNGRADE operation receives a NFS4ERR_OLD_STATEID
> then bump the seqid before resending. Ensure we only bump the seqid
> by 1.
>
> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
> ---
>  fs/nfs/nfs4_fs.h   |  2 --
>  fs/nfs/nfs4proc.c  | 75 ++++++++++++++++++++++++++++++++++++++++++++--
>  fs/nfs/nfs4state.c | 16 ----------
>  3 files changed, 72 insertions(+), 21 deletions(-)
>
> diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
> index e8f74ed98e42..16b2e5cc3e94 100644
> --- a/fs/nfs/nfs4_fs.h
> +++ b/fs/nfs/nfs4_fs.h
> @@ -491,8 +491,6 @@ extern int nfs4_set_lock_state(struct nfs4_state *state, struct file_lock *fl);
>  extern int nfs4_select_rw_stateid(struct nfs4_state *, fmode_t,
>                 const struct nfs_lock_context *, nfs4_stateid *,
>                 const struct cred **);
> -extern bool nfs4_refresh_open_stateid(nfs4_stateid *dst,
> -               struct nfs4_state *state);
>  extern bool nfs4_copy_open_stateid(nfs4_stateid *dst,
>                 struct nfs4_state *state);
>
> diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
> index 025dd5efbf34..c14af2c1c6b6 100644
> --- a/fs/nfs/nfs4proc.c
> +++ b/fs/nfs/nfs4proc.c
> @@ -3308,6 +3308,75 @@ nfs4_wait_on_layoutreturn(struct inode *inode, struct rpc_task *task)
>         return pnfs_wait_on_layoutreturn(inode, task);
>  }
>
> +/*
> + * Update the seqid of an open stateid
> + */
> +static void nfs4_sync_open_stateid(nfs4_stateid *dst,
> +               struct nfs4_state *state)
> +{
> +       __be32 seqid_open;
> +       u32 dst_seqid;
> +       int seq;
> +
> +       for (;;) {
> +               if (!nfs4_valid_open_stateid(state))
> +                       break;
> +               seq = read_seqbegin(&state->seqlock);
> +               if (!nfs4_state_match_open_stateid_other(state, dst)) {
> +                       nfs4_stateid_copy(dst, &state->open_stateid);
> +                       if (read_seqretry(&state->seqlock, seq))
> +                               continue;
> +                       break;
> +               }
> +               seqid_open = state->open_stateid.seqid;
> +               if (read_seqretry(&state->seqlock, seq))
> +                       continue;
> +
> +               dst_seqid = be32_to_cpu(dst->seqid);
> +               if ((s32)(dst_seqid - be32_to_cpu(seqid_open)) < 0)
> +                       dst->seqid = seqid_open;
> +               break;
> +       }
> +}
> +
> +/*
> + * Update the seqid of an open stateid after receiving
> + * NFS4ERR_OLD_STATEID
> + */
> +static bool nfs4_refresh_open_old_stateid(nfs4_stateid *dst,
> +               struct nfs4_state *state)
> +{
> +       __be32 seqid_open;
> +       u32 dst_seqid;
> +       bool ret;
> +       int seq;
> +
> +       for (;;) {
> +               ret = false;
> +               if (!nfs4_valid_open_stateid(state))
> +                       break;
> +               seq = read_seqbegin(&state->seqlock);
> +               if (!nfs4_state_match_open_stateid_other(state, dst)) {
> +                       if (read_seqretry(&state->seqlock, seq))
> +                               continue;
> +                       break;
> +               }
> +               seqid_open = state->open_stateid.seqid;
> +               if (read_seqretry(&state->seqlock, seq))
> +                       continue;
> +
> +               dst_seqid = be32_to_cpu(dst->seqid);
> +               if ((s32)(dst_seqid - be32_to_cpu(seqid_open)) >= 0)
> +                       dst->seqid = cpu_to_be32(dst_seqid + 1);
> +               else
> +                       dst->seqid = seqid_open;
> +               ret = true;
> +               break;
> +       }
> +
> +       return ret;
> +}
> +
>  struct nfs4_closedata {
>         struct inode *inode;
>         struct nfs4_state *state;
> @@ -3382,7 +3451,7 @@ static void nfs4_close_done(struct rpc_task *task, void *data)
>                         break;
>                 case -NFS4ERR_OLD_STATEID:
>                         /* Did we race with OPEN? */
> -                       if (nfs4_refresh_open_stateid(&calldata->arg.stateid,
> +                       if (nfs4_refresh_open_old_stateid(&calldata->arg.stateid,
>                                                 state))
>                                 goto out_restart;
>                         goto out_release;
> @@ -3451,8 +3520,8 @@ static void nfs4_close_prepare(struct rpc_task *task, void *data)
>         } else if (is_rdwr)
>                 calldata->arg.fmode |= FMODE_READ|FMODE_WRITE;
>
> -       if (!nfs4_valid_open_stateid(state) ||
> -           !nfs4_refresh_open_stateid(&calldata->arg.stateid, state))
> +       nfs4_sync_open_stateid(&calldata->arg.stateid, state);
> +       if (!nfs4_valid_open_stateid(state))
>                 call_close = 0;
>         spin_unlock(&state->owner->so_lock);
>
> diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
> index cad4e064b328..e23945174da4 100644
> --- a/fs/nfs/nfs4state.c
> +++ b/fs/nfs/nfs4state.c
> @@ -1015,22 +1015,6 @@ static int nfs4_copy_lock_stateid(nfs4_stateid *dst,
>         return ret;
>  }
>
> -bool nfs4_refresh_open_stateid(nfs4_stateid *dst, struct nfs4_state *state)
> -{
> -       bool ret;
> -       int seq;
> -
> -       do {
> -               ret = false;
> -               seq = read_seqbegin(&state->seqlock);
> -               if (nfs4_state_match_open_stateid_other(state, dst)) {
> -                       dst->seqid = state->open_stateid.seqid;
> -                       ret = true;
> -               }
> -       } while (read_seqretry(&state->seqlock, seq));
> -       return ret;
> -}
> -
>  bool nfs4_copy_open_stateid(nfs4_stateid *dst, struct nfs4_state *state)
>  {
>         bool ret;
> --
> 2.21.0
>
> --
> Trond Myklebust
> Linux NFS client maintainer, Hammerspace
> trond.myklebust@hammerspace.com
>
>