nfsd: reject reclaim request when client has already sent RECLAIM_COMPLETE

As stated in RFC 5661, section 18.51.3:

    Once a RECLAIM_COMPLETE is done, there can be no further reclaim
    operations for locks whose scope is defined as having completed
    recovery.  Once the client sends RECLAIM_COMPLETE, the server will
    not allow the client to do subsequent reclaims of locking state for
    that scope and, if these are attempted, will return
    NFS4ERR_NO_GRACE.

Ensure that we enforce that requirement.
Signed-off-by: Jeff Layton <jlayton@primarydata.com>

fs/nfsd/nfs4state.c

@@ -5650,6 +5650,9 @@ nfs4_check_open_reclaim(clientid_t *clid,
 	if (status)
 		return nfserr_reclaim_bad;
 
+	if (test_bit(NFSD4_CLIENT_RECLAIM_COMPLETE, &cstate->clp->cl_flags))
+		return nfserr_no_grace;
+
 	if (nfsd4_client_record_check(cstate->clp))
 		return nfserr_reclaim_bad;