Eleminate server IO leak on Cancel request (#527)

* Eleminate server IO leak on Cancel request

* Some more fixes

* Apply fmt

---------

Co-authored-by: Andrey M. Borodin <x4mmm@172.25.72.199-ekb.dhcp.yndx.net>

sources/cancel.c

@@ -15,11 +15,10 @@ int od_cancel(od_global_t *global, od_rule_storage_t *storage, kiwi_key_t *key,
 	od_instance_t *instance = global->instance;
 	od_log(&instance->logger, "cancel", NULL, NULL, "cancel for %s%.*s",
 	       server_id->id_prefix, sizeof(server_id->id), server_id->id);
-	od_server_t server;
-	od_server_init(&server, 0);
-	server.global = global;
-	od_backend_connect_cancel(&server, storage, key);
-	od_backend_close_connection(&server);
-	od_backend_close(&server);
+	od_server_t *server = od_server_allocate(0);
+	server->global = global;
+	od_backend_connect_cancel(server, storage, key);
+	od_backend_close_connection(server);
+	od_backend_close(server);
 	return 0;
 }

sources/frontend.c

@@ -535,8 +535,7 @@ static inline bool od_should_drop_connection(od_client_t *client,
 			// general logic is: if client do nothing long enough we can assume this is just a stale connection
 			// but we need to ensure this connection was initialized etc
 			if (od_unlikely(
-				    server != NULL && server->is_allocated &&
-				    !server->is_transaction &&
+				    server != NULL && !server->is_transaction &&
 				    /* case when we are out of any transactional block ut perform some stmt */
 				    od_server_synchronized(server))) {
 				if (od_eject_conn_with_timeout(
@@ -555,9 +554,8 @@ static inline bool od_should_drop_connection(od_client_t *client,
 		}
 		if (od_unlikely(
 			    client->rule->pool->idle_in_transaction_timeout)) {
-			// the save as above but we are going to drop client inside transaction block
-			if (server != NULL && server->is_allocated &&
-			    server->is_transaction &&
+			// the same as above but we are going to drop client inside transaction block
+			if (server != NULL && server->is_transaction &&
 			    /*server is sync - that means client executed some stmts and got get result, and now just... do nothing */
 			    od_server_synchronized(server)) {
 				if (od_eject_conn_with_timeout(
@@ -595,9 +593,6 @@ static inline bool od_should_drop_connection(od_client_t *client,
 			return od_eject_conn_with_rate(client, server,
 						       instance);
 		}
-		if (!server->is_allocated) {
-			return true;
-		}
 		if (server->state ==
 			    OD_SERVER_ACTIVE /* we can drop client that are just connected and do not perform any queries */
 		    && !od_server_synchronized(server)) {
@@ -1711,8 +1706,7 @@ static od_frontend_status_t od_frontend_remote(od_client_t *client)
 			}
 
 #if OD_DEVEL_LVL != OD_RELEASE_MODE
-			if (server != NULL && server->is_allocated &&
-			    server->is_transaction &&
+			if (server != NULL && server->is_transaction &&
 			    od_server_synchronized(server)) {
 				od_dbg_printf_on_dvl_lvl(
 					1,

sources/server.h

@@ -24,7 +24,6 @@ struct od_server {
 	machine_tls_t *tls;
 	od_io_t io;
 	od_relay_t relay;
-	int is_allocated;
 	int is_transaction;
 	/* Copy stmt state */
 	uint64_t done_fail_response_received;
@@ -73,7 +72,6 @@ static inline void od_server_init(od_server_t *server, int reserve_prep_stmts)
 	server->global = NULL;
 	server->tls = NULL;
 	server->idle_time = 0;
-	server->is_allocated = 0;
 	server->is_transaction = 0;
 	server->done_fail_response_received = 0;
 	server->in_out_response_received = 0;
@@ -114,20 +112,17 @@ static inline od_server_t *od_server_allocate(int reserve_prep_stmts)
 	if (server == NULL)
 		return NULL;
 	od_server_init(server, reserve_prep_stmts);
-	server->is_allocated = 1;
 	return server;
 }
 
 static inline void od_server_free(od_server_t *server)
 {
-	if (server->is_allocated) {
-		od_relay_free(&server->relay);
-		od_io_free(&server->io);
-		if (server->prep_stmts) {
-			od_hashmap_free(server->prep_stmts);
-		}
-		free(server);
+	od_relay_free(&server->relay);
+	od_io_free(&server->io);
+	if (server->prep_stmts) {
+		od_hashmap_free(server->prep_stmts);
 	}
+	free(server);
 }
 
 static inline void od_server_sync_request(od_server_t *server, uint64_t count)