NFSv4: Don't tell server we rebooted when not necessary

Instead of doing a full setclientid, try doing a RENEW call first.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/nfs4state.c

@@ -1059,19 +1059,19 @@ static int nfs4_check_lease(struct nfs_client *clp)
 	struct rpc_cred *cred;
 	int status = -NFS4ERR_EXPIRED;
 
-	/* Are there any open files on this volume? */
+	/* Is the client already known to have an expired lease? */
+	if (test_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state))
+		return 0;
 	cred = nfs4_get_renew_cred(clp);
-	if (cred != NULL) {
-		/* Yes there are: try to renew the old lease */
-		status = nfs4_proc_renew(clp, cred);
-		put_rpccred(cred);
-		nfs4_recovery_handle_error(clp, status);
-		return status;
+	if (cred == NULL) {
+		cred = nfs4_get_setclientid_cred(clp);
+		if (cred == NULL)
+			goto out;
 	}
-
-	/* "reboot" to ensure we clear all state on the server */
-	clp->cl_boot_time = CURRENT_TIME;
-	set_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state);
+	status = nfs4_proc_renew(clp, cred);
+	put_rpccred(cred);
+out:
+	nfs4_recovery_handle_error(clp, status);
 	return status;
 }