NFSv4.1: Don't decrease the value of seq_nr_highest_sent

When we're trying to figure out what the server may or may not have seen
in terms of request numbers, do not assume that requests with a larger
number were missed, just because we saw a reply to a request with a
smaller number.

Fixes: 3453d570 ("NFSv4.1: Avoid false retries when RPC calls are interrupted")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/nfs4proc.c

@@ -784,10 +784,9 @@ static void nfs4_slot_sequence_record_sent(struct nfs4_slot *slot,
 	if ((s32)(seqnr - slot->seq_nr_highest_sent) > 0)
 		slot->seq_nr_highest_sent = seqnr;
 }
-static void nfs4_slot_sequence_acked(struct nfs4_slot *slot,
-		u32 seqnr)
+static void nfs4_slot_sequence_acked(struct nfs4_slot *slot, u32 seqnr)
 {
-	slot->seq_nr_highest_sent = seqnr;
+	nfs4_slot_sequence_record_sent(slot, seqnr);
 	slot->seq_nr_last_acked = seqnr;
 }