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From:   Olga Kornievskaia <aglo@umich.edu>
Date:   Thu, 12 Sep 2019 11:04:14 -0400
Message-ID: <CAN-5tyH_NayArVHcyhr4A994kagxftd8SQXdBbP32e_7W-kE7A@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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Sender: linux-nfs-owner@vger.kernel.org
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On Thu, Sep 12, 2019 at 11:01 AM Olga Kornievskaia <aglo@umich.edu> wrote:
>
> 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.

Is the same fix needed for the unlock case? I don't have a good test
case for the unlock.

>
> >
> > 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
> >
> >