staging/lustre/server: use unified request handler for MGS

- Unify request handler. It finds target for particular request and
  calls appropriate handler for it. Generic handlers are moved to
  the unified target code. The tgt_session_info is introduced to
  store all request-related data and passed to all handlers.
- Pack reply in llog server functions early and use err_serious()
- remove obsoleted llog_origin_handle_cancel(), it is not used
  anymore
- remove push_ctxt/pop_ctxt from llog server function, it is based
  on OSD now.

Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-2145
Lustre-change: http://review.whamcloud.com/4826
Signed-off-by: Mikhail Pershin <mike.pershin@intel.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Signed-off-by: Peng Tao <bergwolf@gmail.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/include/lustre_req_layout.h

@@ -245,6 +245,8 @@ extern struct req_format RQF_LLOG_ORIGIN_HANDLE_PREV_BLOCK;
 extern struct req_format RQF_LLOG_ORIGIN_HANDLE_READ_HEADER;
 extern struct req_format RQF_LLOG_ORIGIN_CONNECT;
 
+extern struct req_format RQF_CONNECT;
+
 extern struct req_msg_field RMF_GENERIC_DATA;
 extern struct req_msg_field RMF_PTLRPC_BODY;
 extern struct req_msg_field RMF_MDT_BODY;

drivers/staging/lustre/lustre/include/obd_support.h

@@ -416,6 +416,13 @@ int obd_alloc_fail(const void *ptr, const char *name, const char *type,
 #define OBD_FAIL_MGC_PAUSE_PROCESS_LOG   0x903
 #define OBD_FAIL_MGS_PAUSE_REQ	   0x904
 #define OBD_FAIL_MGS_PAUSE_TARGET_REG    0x905
+#define OBD_FAIL_MGS_CONNECT_NET	 0x906
+#define OBD_FAIL_MGS_DISCONNECT_NET	 0x907
+#define OBD_FAIL_MGS_SET_INFO_NET	 0x908
+#define OBD_FAIL_MGS_EXCEPTION_NET	 0x909
+#define OBD_FAIL_MGS_TARGET_REG_NET	 0x90a
+#define OBD_FAIL_MGS_TARGET_DEL_NET	 0x90b
+#define OBD_FAIL_MGS_CONFIG_READ_NET	 0x90c
 
 #define OBD_FAIL_QUOTA_DQACQ_NET			0xA01
 #define OBD_FAIL_QUOTA_EDQUOT	    0xA02

drivers/staging/lustre/lustre/ptlrpc/layout.c

@@ -738,7 +738,8 @@ static struct req_format *req_formats[] = {
 	&RQF_LLOG_ORIGIN_HANDLE_NEXT_BLOCK,
 	&RQF_LLOG_ORIGIN_HANDLE_PREV_BLOCK,
 	&RQF_LLOG_ORIGIN_HANDLE_READ_HEADER,
-	&RQF_LLOG_ORIGIN_CONNECT
+	&RQF_LLOG_ORIGIN_CONNECT,
+	&RQF_CONNECT,
 };
 
 struct req_msg_field {
@@ -1504,6 +1505,10 @@ struct req_format RQF_LLOG_ORIGIN_CONNECT =
 	DEFINE_REQ_FMT0("LLOG_ORIGIN_CONNECT", llogd_conn_body_only, empty);
 EXPORT_SYMBOL(RQF_LLOG_ORIGIN_CONNECT);
 
+struct req_format RQF_CONNECT =
+	DEFINE_REQ_FMT0("CONNECT", obd_connect_client, obd_connect_server);
+EXPORT_SYMBOL(RQF_CONNECT);
+
 struct req_format RQF_OST_CONNECT =
 	DEFINE_REQ_FMT0("OST_CONNECT",
 			obd_connect_client, obd_connect_server);

drivers/staging/lustre/lustre/ptlrpc/lproc_ptlrpc.c

@@ -114,10 +114,10 @@ struct ll_rpc_opcode {
 	{ MGS_SET_INFO,     "mgs_set_info" },
 	{ MGS_CONFIG_READ,  "mgs_config_read" },
 	{ OBD_PING,	 "obd_ping" },
-	{ OBD_LOG_CANCEL,   "llog_origin_handle_cancel" },
+	{ OBD_LOG_CANCEL,	"llog_cancel" },
 	{ OBD_QC_CALLBACK,  "obd_quota_callback" },
 	{ OBD_IDX_READ,	    "dt_index_read" },
-	{ LLOG_ORIGIN_HANDLE_CREATE,     "llog_origin_handle_create" },
+	{ LLOG_ORIGIN_HANDLE_CREATE,	 "llog_origin_handle_open" },
 	{ LLOG_ORIGIN_HANDLE_NEXT_BLOCK, "llog_origin_handle_next_block" },
 	{ LLOG_ORIGIN_HANDLE_READ_HEADER,"llog_origin_handle_read_header" },
 	{ LLOG_ORIGIN_HANDLE_WRITE_REC,  "llog_origin_handle_write_rec" },