nfsd4: return "real" sequence id in confirmed case

The client should ignore the returned sequence_id in the case where the
CONFIRMED flag is set on an exchange_id reply--and in the unconfirmed
case "1" is always the right response.  So it shouldn't actually matter
what we return here.

We could continue returning 1 just to catch clients ignoring the spec
here, but I'd rather be generous.  Other things equal, returning the
existing sequence_id seems more informative.
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4state.c

@@ -1650,7 +1650,7 @@ nfsd4_exchange_id(struct svc_rqst *rqstp,
 	exid->clientid.cl_boot = new->cl_clientid.cl_boot;
 	exid->clientid.cl_id = new->cl_clientid.cl_id;
 
-	exid->seqid = 1;
+	exid->seqid = new->cl_cs_slot.sl_seqid + 1;
 	nfsd4_set_ex_flags(new, exid);
 
 	dprintk("nfsd4_exchange_id seqid %d flags %x\n",