[PATCH 1/3] NFSv4.1: Try to deal with NFS4ERR_SEQ_MISORDERED.

[PATCH 1/3] NFSv4.1: Try to deal with NFS4ERR_SEQ_MISORDERED.

[Trond Myklebust]

If the server returns NFS4ERR_SEQ_MISORDERED, it could be a sign
that the slot was retired at some point. Retry the attempt after
reinitialising the slot sequence number to 1.

Also add a handler for NFS4ERR_SEQ_FALSE_RETRY. Just bump the slot
sequence number and retry...

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---
 fs/nfs/nfs4proc.c | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index b0963ae..9003b8f 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -467,11 +467,19 @@ static int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *
 		 * The slot id we used was probably retired. Try again
 		 * using a different slot id.
 		 */
-		if (rpc_restart_call_prepare(task)) {
-			task->tk_status = 0;
-			ret = 0;
-		}
-		break;
+		goto retry_nowait;
+	case -NFS4ERR_SEQ_MISORDERED:
+		/*
+		 * Could this slot have been previously retired?
+		 * If so, then the server may be expecting seq_nr = 1!
+		 */
+		if (slot->seq_nr == 1)
+			break;
+		slot->seq_nr = 1;
+		goto retry_nowait;
+	case -NFS4ERR_SEQ_FALSE_RETRY:
+		++slot->seq_nr;
+		goto retry_nowait;
 	default:
 		/* Just update the slot sequence no. */
 		++slot->seq_nr;
@@ -481,6 +489,12 @@ out:
 	dprintk("%s: Error %d free the slot \n", __func__, res->sr_status);
 	nfs41_sequence_free_slot(res);
 	return ret;
+retry_nowait:
+	if (rpc_restart_call_prepare(task)) {
+		task->tk_status = 0;
+		ret = 0;
+	}
+	goto out;
 out_retry:
 	if (!rpc_restart_call(task))
 		goto out;
-- 
1.7.11.7

[PATCH 2/3] NFSv4.1: Move the RPC timestamp out of the slot.

[Trond Myklebust]

Shave a few bytes off the slot table size by moving the RPC timestamp
into the sequence results.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---
 fs/nfs/nfs4proc.c       | 14 +++++++-------
 fs/nfs/nfs4session.c    |  3 +--
 fs/nfs/nfs4session.h    |  1 -
 include/linux/nfs_xdr.h |  1 +
 4 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 9003b8f..afb428e 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -419,7 +419,6 @@ static int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *
 {
 	struct nfs4_session *session;
 	struct nfs4_slot *slot;
-	unsigned long timestamp;
 	struct nfs_client *clp;
 	int ret = 1;
 
@@ -444,9 +443,8 @@ static int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *
 	case 0:
 		/* Update the slot's sequence and clientid lease timer */
 		++slot->seq_nr;
-		timestamp = slot->renewal_time;
 		clp = session->clp;
-		do_renew_lease(clp, timestamp);
+		do_renew_lease(clp, res->sr_timestamp);
 		/* Check sequence flags */
 		if (res->sr_status_flags != 0)
 			nfs4_schedule_lease_recovery(clp);
@@ -473,10 +471,11 @@ static int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *
 		 * Could this slot have been previously retired?
 		 * If so, then the server may be expecting seq_nr = 1!
 		 */
-		if (slot->seq_nr == 1)
-			break;
-		slot->seq_nr = 1;
-		goto retry_nowait;
+		if (slot->seq_nr != 1) {
+			slot->seq_nr = 1;
+			goto retry_nowait;
+		}
+		break;
 	case -NFS4ERR_SEQ_FALSE_RETRY:
 		++slot->seq_nr;
 		goto retry_nowait;
@@ -567,6 +566,7 @@ int nfs41_setup_sequence(struct nfs4_session *session,
 			slot->slot_nr, slot->seq_nr);
 
 	res->sr_slot = slot;
+	res->sr_timestamp = jiffies;
 	res->sr_status_flags = 0;
 	/*
 	 * sr_status is only set in decode_sequence, and so will remain
diff --git a/fs/nfs/nfs4session.c b/fs/nfs/nfs4session.c
index 1e6c87c..0e1cc1f 100644
--- a/fs/nfs/nfs4session.c
+++ b/fs/nfs/nfs4session.c
@@ -143,7 +143,6 @@ struct nfs4_slot *nfs4_alloc_slot(struct nfs4_slot_table *tbl)
 	if (slotid > tbl->highest_used_slotid ||
 			tbl->highest_used_slotid == NFS4_NO_SLOT)
 		tbl->highest_used_slotid = slotid;
-	ret->renewal_time = jiffies;
 	ret->generation = tbl->generation;
 
 out:
@@ -228,9 +227,9 @@ static bool nfs41_assign_slot(struct rpc_task *task, void *pslot)
 
 	if (nfs4_session_draining(tbl->session) && !args->sa_privileged)
 		return false;
-	slot->renewal_time = jiffies;
 	slot->generation = tbl->generation;
 	args->sa_slot = slot;
+	res->sr_timestamp = jiffies;
 	res->sr_slot = slot;
 	res->sr_status_flags = 0;
 	res->sr_status = 1;
diff --git a/fs/nfs/nfs4session.h b/fs/nfs/nfs4session.h
index 04f834c..d17b080 100644
--- a/fs/nfs/nfs4session.h
+++ b/fs/nfs/nfs4session.h
@@ -19,7 +19,6 @@ struct nfs4_slot {
 	struct nfs4_slot_table	*table;
 	struct nfs4_slot	*next;
 	unsigned long		generation;
-	unsigned long		renewal_time;
 	u32			slot_nr;
 	u32		 	seq_nr;
 };
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index a55abd4..29adb12 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -194,6 +194,7 @@ struct nfs4_sequence_args {
 
 struct nfs4_sequence_res {
 	struct nfs4_slot	*sr_slot;	/* slot used to send request */
+	unsigned long		sr_timestamp;
 	int			sr_status;	/* sequence operation status */
 	u32			sr_status_flags;
 	u32			sr_highest_slotid;
-- 
1.7.11.7

[PATCH 3/3] NFSv4.1: Deal effectively with interrupted RPC calls.

[Trond Myklebust]

If an RPC call is interrupted, assume that the server hasn't processed
the RPC call so that the next time we use the slot, we know that if we
get a NFS4ERR_SEQ_MISORDERED or NFS4ERR_SEQ_FALSE_RETRY, we just have
to bump the sequence number.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
---
 fs/nfs/nfs4proc.c    | 32 +++++++++++++++++++++++---------
 fs/nfs/nfs4session.c |  1 +
 fs/nfs/nfs4session.h |  1 +
 3 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index afb428e..493f0f4 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -420,17 +420,9 @@ static int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *
 	struct nfs4_session *session;
 	struct nfs4_slot *slot;
 	struct nfs_client *clp;
+	bool interrupted = false;
 	int ret = 1;
 
-	/*
-	 * sr_status remains 1 if an RPC level error occurred. The server
-	 * may or may not have processed the sequence operation..
-	 * Proceed as if the server received and processed the sequence
-	 * operation.
-	 */
-	if (res->sr_status == 1)
-		res->sr_status = NFS_OK;
-
 	/* don't increment the sequence number if the task wasn't sent */
 	if (!RPC_WAS_SENT(task))
 		goto out;
@@ -438,6 +430,11 @@ static int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *
 	slot = res->sr_slot;
 	session = slot->table->session;
 
+	if (slot->interrupted) {
+		slot->interrupted = 0;
+		interrupted = true;
+	}
+
 	/* Check the SEQUENCE operation status */
 	switch (res->sr_status) {
 	case 0:
@@ -450,6 +447,15 @@ static int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *
 			nfs4_schedule_lease_recovery(clp);
 		nfs41_update_target_slotid(slot->table, slot, res);
 		break;
+	case 1:
+		/*
+		 * sr_status remains 1 if an RPC level error occurred.
+		 * The server may or may not have processed the sequence
+		 * operation..
+		 * Mark the slot as having hosted an interrupted RPC call.
+		 */
+		slot->interrupted = 1;
+		goto out;
 	case -NFS4ERR_DELAY:
 		/* The server detected a resend of the RPC call and
 		 * returned NFS4ERR_DELAY as per Section 2.10.6.2
@@ -468,6 +474,14 @@ static int nfs41_sequence_done(struct rpc_task *task, struct nfs4_sequence_res *
 		goto retry_nowait;
 	case -NFS4ERR_SEQ_MISORDERED:
 		/*
+		 * Was the last operation on this sequence interrupted?
+		 * If so, retry after bumping the sequence number.
+		 */
+		if (interrupted) {
+			++slot->seq_nr;
+			goto retry_nowait;
+		}
+		/*
 		 * Could this slot have been previously retired?
 		 * If so, then the server may be expecting seq_nr = 1!
 		 */
diff --git a/fs/nfs/nfs4session.c b/fs/nfs/nfs4session.c
index 0e1cc1f..ebda5f4 100644
--- a/fs/nfs/nfs4session.c
+++ b/fs/nfs/nfs4session.c
@@ -172,6 +172,7 @@ static void nfs4_reset_slot_table(struct nfs4_slot_table *tbl,
 	p = &tbl->slots;
 	while (*p) {
 		(*p)->seq_nr = ivalue;
+		(*p)->interrupted = 0;
 		p = &(*p)->next;
 	}
 	tbl->highest_used_slotid = NFS4_NO_SLOT;
diff --git a/fs/nfs/nfs4session.h b/fs/nfs/nfs4session.h
index d17b080..6f3cb39 100644
--- a/fs/nfs/nfs4session.h
+++ b/fs/nfs/nfs4session.h
@@ -21,6 +21,7 @@ struct nfs4_slot {
 	unsigned long		generation;
 	u32			slot_nr;
 	u32		 	seq_nr;
+	unsigned int		interrupted : 1;
 };
 
 /* Sessions */
-- 
1.7.11.7