+/*
+ * Our current back channel implmentation supports a single backchannel
+ * with a single slot.
+ */
+static int
+decode_cb_sequence(struct xdr_stream *xdr, struct nfsd4_cb_sequence *res,
+ struct rpc_rqst *rqstp)
+{
+ struct nfs4_sessionid id;
+ int status;
+ u32 dummy;
+ __be32 *p;
+
+ if (res->cbs_minorversion == 0)
+ return 0;
+
+ status = decode_cb_op_hdr(xdr, OP_CB_SEQUENCE);
+ if (status)
+ return status;
+
+ /*
+ * If the server returns different values for sessionID, slotID or
+ * sequence number, the server is looney tunes.
+ */
+ status = -ESERVERFAULT;
+
+ READ_BUF(NFS4_MAX_SESSIONID_LEN + 16);
+ memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
+ p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
+ if (memcmp(id.data, res->cbs_clp->cl_sessionid.data,
+ NFS4_MAX_SESSIONID_LEN)) {
+ dprintk("%s Invalid session id\n", __func__);
+ goto out;
+ }
+ READ32(dummy);
+ if (dummy != res->cbs_clp->cl_cb_seq_nr) {
+ dprintk("%s Invalid sequence number\n", __func__);
+ goto out;
+ }
+ READ32(dummy); /* slotid must be 0 */
+ if (dummy != 0) {
+ dprintk("%s Invalid slotid\n", __func__);
+ goto out;
+ }
+ /* FIXME: process highest slotid and target highest slotid */
+ status = 0;
+out:
+ return status;
+}
+
+