NFS4.1 handle interrupted slot reuse from ERR_DELAY

If the RPC slot was interrupted and server replied to the next
operation on the "reused" slot with ERR_DELAY, don't clear out
the "interrupted" flag until we properly recover.
Signed-off-by: NOlga Kornievskaia <kolga@netapp.com>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

fs/nfs/nfs4proc.c

@@ -698,7 +698,8 @@ static int nfs41_sequence_process(struct rpc_task *task,
 	session = slot->table->session;
 
 	if (slot->interrupted) {
-		slot->interrupted = 0;
+		if (res->sr_status != -NFS4ERR_DELAY)
+			slot->interrupted = 0;
 		interrupted = true;
 	}