rpc: duplicate request cache for nfs

Duplicate request cache provides a mechanism for detecting
duplicate rpc requests from clients. DRC caches replies
and on duplicate requests, sends the cached reply instead of
re-processing the request.

Change-Id: I3d62a6c4aa86c92bf61f1038ca62a1a46bf1c303
BUG: 847624
Signed-off-by: Rajesh Amaravathi <rajesh@redhat.com>
Reviewed-on: http://review.gluster.org/4049
Reviewed-by: Rajesh Joseph <rjoseph@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Anand Avati <avati@redhat.com>

1 files changed, 100 insertions, 0 deletions

diff --git a/rpc/rpc-lib/src/rpc-drc.h b/rpc/rpc-lib/src/rpc-drc.h
new file mode 100644
index 00000000000..0a1688992d5
--- /dev/null
+++ b/rpc/rpc-lib/src/rpc-drc.h
@@ -0,0 +1,100 @@
+/*
+  Copyright (c) 2013 Red Hat, Inc. <http://www.redhat.com>
+  This file is part of GlusterFS.
+
+  This file is licensed to you under your choice of the GNU Lesser
+  General Public License, version 3 or any later version (LGPLv3 or
+  later), or the GNU General Public License, version 2 (GPLv2), in all
+  cases as published by the Free Software Foundation.
+*/
+
+#ifndef RPC_DRC_H
+#define RPC_DRC_H
+
+#ifndef _CONFIG_H
+#define _CONFIG_H
+#include "config.h"
+#endif
+
+#include "rpcsvc-common.h"
+#include "rpcsvc.h"
+#include "locking.h"
+#include "dict.h"
+#include "rb.h"
+
+/* per-client cache structure */
+struct drc_client {
+        uint32_t                   ref;
+        union gf_sock_union        sock_union;
+        /* pointers to the cache */
+        struct rb_table           *rbtree;
+        /* no. of ops currently cached */
+        uint32_t                   op_count;
+        struct list_head           client_list;
+};
+
+struct drc_cached_op {
+        drc_op_state_t                 state;
+        uint32_t                       xid;
+        int                            prognum;
+        int                            progversion;
+        int                            procnum;
+        rpc_transport_msg_t            msg;
+        drc_client_t                  *client;
+        struct list_head               client_list;
+        struct list_head               global_list;
+        int32_t                        ref;
+};
+
+/* global drc definitions */
+enum drc_status {
+        DRC_UNINITIATED,
+        DRC_INITIATED
+};
+typedef enum drc_status drc_status_t;
+
+struct drc_globals {
+        /* allocator must be the first member since
+         * it is used so in gf_libavl_allocator
+         */
+        struct libavl_allocator   allocator;
+        drc_type_t                type;
+        /* configurable size parameter */
+        uint32_t                  global_cache_size;
+        drc_lru_factor_t          lru_factor;
+        gf_lock_t                 lock;
+        drc_status_t              status;
+        uint32_t                  op_count;
+        uint64_t                  cache_hits;
+        uint64_t                  intransit_hits;
+        struct mem_pool          *mempool;
+        struct list_head          cache_head;
+        uint32_t                  client_count;
+        struct list_head          clients_head;
+};
+
+int
+rpcsvc_need_drc (rpcsvc_request_t *req);
+
+drc_cached_op_t *
+rpcsvc_drc_lookup (rpcsvc_request_t *req);
+
+int
+rpcsvc_send_cached_reply (rpcsvc_request_t *req, drc_cached_op_t *reply);
+
+int
+rpcsvc_cache_reply (rpcsvc_request_t *req, struct iobref *iobref,
+                    struct iovec *rpchdr, int rpchdrcount,
+                    struct iovec *proghdr, int proghdrcount,
+                    struct iovec *payload, int payloadcount);
+
+int
+rpcsvc_cache_request (rpcsvc_request_t *req);
+
+int32_t
+rpcsvc_drc_priv (rpcsvc_drc_globals_t *drc);
+
+int
+rpcsvc_drc_init (rpcsvc_t *svc, dict_t *options);
+
+#endif /* RPC_DRC_H */