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-rw-r--r--fs/nfs/callback_proc.c127
1 files changed, 127 insertions, 0 deletions
diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index f7e83e23cf9f..b7da1f54da68 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -101,3 +101,130 @@ out:
dprintk("%s: exit with status = %d\n", __func__, ntohl(res));
return res;
}
+
+#if defined(CONFIG_NFS_V4_1)
+
+/*
+ * Validate the sequenceID sent by the server.
+ * Return success if the sequenceID is one more than what we last saw on
+ * this slot, accounting for wraparound. Increments the slot's sequence.
+ *
+ * We don't yet implement a duplicate request cache, so at this time
+ * we will log replays, and process them as if we had not seen them before,
+ * but we don't bump the sequence in the slot. Not too worried about it,
+ * since we only currently implement idempotent callbacks anyway.
+ *
+ * We have a single slot backchannel at this time, so we don't bother
+ * checking the used_slots bit array on the table. The lower layer guarantees
+ * a single outstanding callback request at a time.
+ */
+static int
+validate_seqid(struct nfs4_slot_table *tbl, u32 slotid, u32 seqid)
+{
+ struct nfs4_slot *slot;
+
+ dprintk("%s enter. slotid %d seqid %d\n",
+ __func__, slotid, seqid);
+
+ if (slotid > NFS41_BC_MAX_CALLBACKS)
+ return htonl(NFS4ERR_BADSLOT);
+
+ slot = tbl->slots + slotid;
+ dprintk("%s slot table seqid: %d\n", __func__, slot->seq_nr);
+
+ /* Normal */
+ if (likely(seqid == slot->seq_nr + 1)) {
+ slot->seq_nr++;
+ return htonl(NFS4_OK);
+ }
+
+ /* Replay */
+ if (seqid == slot->seq_nr) {
+ dprintk("%s seqid %d is a replay - no DRC available\n",
+ __func__, seqid);
+ return htonl(NFS4_OK);
+ }
+
+ /* Wraparound */
+ if (seqid == 1 && (slot->seq_nr + 1) == 0) {
+ slot->seq_nr = 1;
+ return htonl(NFS4_OK);
+ }
+
+ /* Misordered request */
+ return htonl(NFS4ERR_SEQ_MISORDERED);
+}
+
+/*
+ * Returns a pointer to a held 'struct nfs_client' that matches the server's
+ * address, major version number, and session ID. It is the caller's
+ * responsibility to release the returned reference.
+ *
+ * Returns NULL if there are no connections with sessions, or if no session
+ * matches the one of interest.
+ */
+ static struct nfs_client *find_client_with_session(
+ const struct sockaddr *addr, u32 nfsversion,
+ struct nfs4_sessionid *sessionid)
+{
+ struct nfs_client *clp;
+
+ clp = nfs_find_client(addr, 4);
+ if (clp == NULL)
+ return NULL;
+
+ do {
+ struct nfs_client *prev = clp;
+
+ if (clp->cl_session != NULL) {
+ if (memcmp(clp->cl_session->sess_id.data,
+ sessionid->data,
+ NFS4_MAX_SESSIONID_LEN) == 0) {
+ /* Returns a held reference to clp */
+ return clp;
+ }
+ }
+ clp = nfs_find_client_next(prev);
+ nfs_put_client(prev);
+ } while (clp != NULL);
+
+ return NULL;
+}
+
+/* FIXME: referring calls should be processed */
+unsigned nfs4_callback_sequence(struct cb_sequenceargs *args,
+ struct cb_sequenceres *res)
+{
+ struct nfs_client *clp;
+ int i, status;
+
+ for (i = 0; i < args->csa_nrclists; i++)
+ kfree(args->csa_rclists[i].rcl_refcalls);
+ kfree(args->csa_rclists);
+
+ status = htonl(NFS4ERR_BADSESSION);
+ clp = find_client_with_session(args->csa_addr, 4, &args->csa_sessionid);
+ if (clp == NULL)
+ goto out;
+
+ status = validate_seqid(&clp->cl_session->bc_slot_table,
+ args->csa_slotid, args->csa_sequenceid);
+ if (status)
+ goto out_putclient;
+
+ memcpy(&res->csr_sessionid, &args->csa_sessionid,
+ sizeof(res->csr_sessionid));
+ res->csr_sequenceid = args->csa_sequenceid;
+ res->csr_slotid = args->csa_slotid;
+ res->csr_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
+ res->csr_target_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
+
+out_putclient:
+ nfs_put_client(clp);
+out:
+ dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
+ res->csr_status = status;
+ return res->csr_status;
+}
+
+#endif /* CONFIG_NFS_V4_1 */