Received-SPF: pass (google.com: best guess record for domain of linux-nfs-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Trond Myklebust <trondmy@gmail.com>
To:     linux-nfs@vger.kernel.org
Subject: [PATCH v2 19/20] NFSv4: Handle NFS4ERR_OLD_STATEID in delegreturn
Date:   Thu, 31 Oct 2019 18:40:50 -0400
Message-Id: <20191031224051.8923-20-trond.myklebust@hammerspace.com>
In-Reply-To: <20191031224051.8923-19-trond.myklebust@hammerspace.com>
References: <20191031224051.8923-1-trond.myklebust@hammerspace.com>
 <20191031224051.8923-2-trond.myklebust@hammerspace.com>
 <20191031224051.8923-3-trond.myklebust@hammerspace.com>
 <20191031224051.8923-4-trond.myklebust@hammerspace.com>
 <20191031224051.8923-5-trond.myklebust@hammerspace.com>
 <20191031224051.8923-6-trond.myklebust@hammerspace.com>
 <20191031224051.8923-7-trond.myklebust@hammerspace.com>
 <20191031224051.8923-8-trond.myklebust@hammerspace.com>
 <20191031224051.8923-9-trond.myklebust@hammerspace.com>
 <20191031224051.8923-10-trond.myklebust@hammerspace.com>
 <20191031224051.8923-11-trond.myklebust@hammerspace.com>
 <20191031224051.8923-12-trond.myklebust@hammerspace.com>
 <20191031224051.8923-13-trond.myklebust@hammerspace.com>
 <20191031224051.8923-14-trond.myklebust@hammerspace.com>
 <20191031224051.8923-15-trond.myklebust@hammerspace.com>
 <20191031224051.8923-16-trond.myklebust@hammerspace.com>
 <20191031224051.8923-17-trond.myklebust@hammerspace.com>
 <20191031224051.8923-18-trond.myklebust@hammerspace.com>
 <20191031224051.8923-19-trond.myklebust@hammerspace.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-nfs-owner@vger.kernel.org
Precedence: bulk

If the server returns NFS4ERR_OLD_STATEID in response to our delegreturn,
we want to sync to the most recent seqid for the delegation stateid. However
if we are already at the most recent, we have two possibilities:

- an OPEN reply is still outstanding and will return a new seqid
- an earlier OPEN reply was dropped on the floor due to a timeout.

In the latter case, we may end up unable to complete the delegreturn,
so we want to bump the seqid to a value greater than the cached value.
While this may cause us to lose the delegation in the former case,
it should now be safe to assume that the client will replay the OPEN
if necessary in order to get a new valid stateid.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
 fs/nfs/delegation.c | 1 +
 fs/nfs/nfs4proc.c   | 7 +++----
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 48f3c6c9672f..fe57b2b5314a 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -1252,6 +1252,7 @@ bool nfs4_refresh_delegation_stateid(nfs4_stateid *dst, struct inode *inode)
 	delegation = rcu_dereference(NFS_I(inode)->delegation);
 	if (delegation != NULL &&
 	    nfs4_stateid_match_other(dst, &delegation->stateid) &&
+	    nfs4_stateid_is_newer(&delegation->stateid, dst) &&
 	    !test_bit(NFS_DELEGATION_REVOKED, &delegation->flags)) {
 		dst->seqid = delegation->stateid.seqid;
 		ret = true;
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index c7e4a9ba8420..33a8e53e976c 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -6196,10 +6196,9 @@ static void nfs4_delegreturn_done(struct rpc_task *task, void *calldata)
 		task->tk_status = 0;
 		break;
 	case -NFS4ERR_OLD_STATEID:
-		if (nfs4_refresh_delegation_stateid(&data->stateid, data->inode))
-			goto out_restart;
-		task->tk_status = 0;
-		break;
+		if (!nfs4_refresh_delegation_stateid(&data->stateid, data->inode))
+			nfs4_stateid_seqid_inc(&data->stateid);
+		goto out_restart;
 	case -NFS4ERR_ACCESS:
 		if (data->args.bitmask) {
 			data->args.bitmask = NULL;
-- 
2.23.0