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, 48 insertions, 0 deletions

diff --git a/rpc/rpc-lib/src/rpcsvc-common.h b/rpc/rpc-lib/src/rpcsvc-common.h
index 2c6f074886d..054e187c96d 100644
--- a/rpc/rpc-lib/src/rpcsvc-common.h
+++ b/rpc/rpc-lib/src/rpcsvc-common.h
@@ -30,6 +30,8 @@ struct rpcsvc_state;
 typedef int (*rpcsvc_notify_t) (struct rpcsvc_state *, void *mydata,
                                 rpcsvc_event_t, void *data);
 
+struct drc_globals;
+typedef struct drc_globals rpcsvc_drc_globals_t;
 
 /* Contains global state required for all the RPC services.
  */
@@ -68,7 +70,53 @@ typedef struct rpcsvc_state {
         void                    *mydata; /* This is xlator */
         rpcsvc_notify_t          notifyfn;
         struct mem_pool         *rxpool;
+        rpcsvc_drc_globals_t    *drc;
 } rpcsvc_t;
 
+/* DRC START */
+enum drc_op_type {
+        DRC_NA              = 0,
+        DRC_IDEMPOTENT      = 1,
+        DRC_NON_IDEMPOTENT  = 2
+};
+typedef enum drc_op_type drc_op_type_t;
+
+enum drc_type {
+        DRC_TYPE_NONE        = 0,
+        DRC_TYPE_IN_MEMORY   = 1
+};
+typedef enum drc_type drc_type_t;
+
+enum drc_lru_factor {
+        DRC_LRU_5_PC       = 20,
+        DRC_LRU_10_PC      = 10,
+        DRC_LRU_25_PC      = 4,
+        DRC_LRU_50_PC      = 2
+};
+typedef enum drc_lru_factor drc_lru_factor_t;
+
+enum drc_xid_state {
+        DRC_XID_MONOTONOUS  = 0,
+        DRC_XID_WRAPPED     = 1
+};
+typedef enum drc_xid_state drc_xid_state_t;
+
+enum drc_op_state {
+        DRC_OP_IN_TRANSIT    = 0,
+        DRC_OP_CACHED        = 1
+};
+typedef enum drc_op_state drc_op_state_t;
+
+enum drc_policy {
+        DRC_LRU              = 0
+};
+typedef enum drc_policy drc_policy_t;
+
+/* Default policies for DRC */
+#define DRC_DEFAULT_TYPE               DRC_TYPE_IN_MEMORY
+#define DRC_DEFAULT_CACHE_SIZE         0x20000
+#define DRC_DEFAULT_LRU_FACTOR         DRC_LRU_25_PC
+
+/* DRC END */
 
 #endif /* #ifndef _RPCSVC_COMMON_H */