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NFS: Fix interrupted slots by sending a solo SEQUENCE operation

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We used to do this before 3453d5708b, but this was changed to better
handle the NFS4ERR_SEQ_MISORDERED error code. This commit fixed the slot
re-use case when the server doesn't receive the interrupted operation,
but if the server does receive the operation then it could still end up
replying to the client with mis-matched operations from the reply cache.

We can fix this by sending a SEQUENCE to the server while recovering from
a SEQ_MISORDERED error when we detect that we are in an interrupted slot
situation.

Fixes: 3453d5708b (NFSv4.1: Avoid false retries when RPC calls are interrupted)
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
Anna Schumaker 2020-07-08 10:33:40 -04:00
parent af667527b0
commit 913fadc5b1
1 changed files with 18 additions and 2 deletions
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20
fs/nfs/nfs4proc.c
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@ -774,6 +774,14 @@ static void nfs4_slot_sequence_acked(struct nfs4_slot *slot,
slot->seq_nr_last_acked = seqnr;
}
static void nfs4_probe_sequence(struct nfs_client *client, const struct cred *cred,
struct nfs4_slot *slot)
{
struct rpc_task *task = _nfs41_proc_sequence(client, cred, slot, true);
if (!IS_ERR(task))
rpc_put_task_async(task);
}
static int nfs41_sequence_process(struct rpc_task *task,
struct nfs4_sequence_res *res)
{
@ -790,6 +798,7 @@ static int nfs41_sequence_process(struct rpc_task *task,
goto out;
session = slot->table->session;
clp = session->clp;
trace_nfs4_sequence_done(session, res);
@ -804,7 +813,6 @@ static int nfs41_sequence_process(struct rpc_task *task,
nfs4_slot_sequence_acked(slot, slot->seq_nr);
/* Update the slot's sequence and clientid lease timer */
slot->seq_done = 1;
clp = session->clp;
do_renew_lease(clp, res->sr_timestamp);
/* Check sequence flags */
nfs41_handle_sequence_flag_errors(clp, res->sr_status_flags,
@ -852,10 +860,18 @@ static int nfs41_sequence_process(struct rpc_task *task,
/*
* Were one or more calls using this slot interrupted?
* If the server never received the request, then our
* transmitted slot sequence number may be too high.
* transmitted slot sequence number may be too high. However,
* if the server did receive the request then it might
* accidentally give us a reply with a mismatched operation.
* We can sort this out by sending a lone sequence operation
* to the server on the same slot.
*/
if ((s32)(slot->seq_nr - slot->seq_nr_last_acked) > 1) {
slot->seq_nr--;
if (task->tk_msg.rpc_proc != &nfs4_procedures[NFSPROC4_CLNT_SEQUENCE]) {
nfs4_probe_sequence(clp, task->tk_msg.rpc_cred, slot);
res->sr_slot = NULL;
}
goto retry_nowait;
}
/*