[sheepdog] [PATCH V3 2/3] sheep: remove unregister_event from process_event_queue()

[Yunkai Zhang]

From: Yunkai Zhang <qiushu.zyk at taobao.com>

This is V3, I have make some simple testing with zookeeper dirver.
---------------------------------------------------------------- >8

In old code, we call unregister_event(cdrv_fd, ...) in process_event_queue()
when sheep receives cluster EVENT, we will register cdrv_fd into epoll again
in event_done() after __sd_xxx() finished.

This is dangerous! In our testing, for some reason, __sd_xxx() may be blocked
by network issue, as a result event_done() would not be executed, and cdrv_fd
would keep outstanding from epoll, then all new coming EVENT could not be
process immediately. This will make sheep hard to complete recovery.

Now, we call update_cluster_info() in sd_xxx_handler() directly so that we can
process new EVENT one by one immediately, and needn't to wait previous EVENT's
__sd_xxx() finished.  So we can remove unregister_event() from
process_event_queue() safely.

Signed-off-by: Yunkai Zhang <qiushu.zyk at taobao.com>
---
 sheep/group.c |   39 ++++++++++++++-------------------------
 1 files changed, 14 insertions(+), 25 deletions(-)

diff --git a/sheep/group.c b/sheep/group.c
index a5311fc..e37e049 100644
--- a/sheep/group.c
+++ b/sheep/group.c
@@ -830,11 +830,6 @@ static void __sd_join_done(struct event_struct *cevent)
 
 	print_node_list(sys->nodes, sys->nr_nodes);
 
-	if (!sys_stat_join_failed()) {
-		update_cluster_info(jm, &w->joined, w->member_list,
-				    w->member_list_entries);
-	}
-
 	if (sys_can_recover() && jm->inc_epoch) {
 		list_for_each_entry_safe(node, t, &sys->leave_list, list) {
 			list_del(&node->list);
@@ -854,19 +849,6 @@ static void __sd_join_done(struct event_struct *cevent)
 
 static void __sd_leave_done(struct event_struct *cevent)
 {
-	struct work_leave *w = container_of(cevent, struct work_leave, cev);
-
-	sys->nr_nodes = w->member_list_entries;
-	memcpy(sys->nodes, w->member_list, sizeof(*sys->nodes) * sys->nr_nodes);
-	qsort(sys->nodes, sys->nr_nodes, sizeof(*sys->nodes), node_cmp);
-
-	if (sys_can_recover()) {
-		sys->epoch++;
-		update_epoch_store(sys->epoch);
-		update_epoch_log(sys->epoch);
-	}
-	update_vnode_info();
-
 	print_node_list(sys->nodes, sys->nr_nodes);
 
 	if (sys_can_recover())
@@ -934,7 +916,6 @@ static void event_fn(struct work *work)
 static void event_done(struct work *work)
 {
 	struct event_struct *cevent;
-	int ret;
 
 	if (!sys->cur_cevent)
 		vprintf(SDOG_ERR, "bug\n");
@@ -961,9 +942,6 @@ static void event_done(struct work *work)
 	vprintf(SDOG_DEBUG, "free %p\n", cevent);
 	event_free(cevent);
 	event_running = 0;
-	ret = register_event(cdrv_fd, group_handler, NULL);
-	if (ret)
-		panic("failed to register event fd");
 
 	process_request_event_queues();
 }
@@ -1067,7 +1045,6 @@ static inline void process_event_queue(void)
 	event_work.fn = event_fn;
 	event_work.done = event_done;
 
-	unregister_event(cdrv_fd);
 	queue_work(sys->event_wqueue, &event_work);
 }
 
@@ -1089,7 +1066,7 @@ void sd_join_handler(struct sd_node *joined, struct sd_node *members,
 	int i, size;
 	int nr, nr_local, nr_leave;
 	struct node *n;
-	struct join_message *jm;
+	struct join_message *jm = opaque;
 	uint32_t le = get_latest_epoch();
 
 	if (node_eq(joined, &sys->this_node)) {
@@ -1113,6 +1090,8 @@ void sd_join_handler(struct sd_node *joined, struct sd_node *members,
 		if (sys_stat_shutdown())
 			break;
 
+		update_cluster_info(jm, joined, members, nr_members);
+
 		w = zalloc(sizeof(*w));
 		if (!w)
 			panic("failed to allocate memory");
@@ -1171,7 +1150,6 @@ void sd_join_handler(struct sd_node *joined, struct sd_node *members,
 		}
 		break;
 	case CJ_RES_MASTER_TRANSFER:
-		jm = (struct join_message *)opaque;
 		nr = jm->nr_leave_nodes;
 		for (i = 0; i < nr; i++) {
 			if (find_entry_list(&jm->leave_nodes[i], &sys->leave_list)
@@ -1232,6 +1210,17 @@ void sd_leave_handler(struct sd_node *left, struct sd_node *members,
 	if (sys_stat_shutdown())
 		return;
 
+	sys->nr_nodes = nr_members;
+	memcpy(sys->nodes, members, sizeof(*sys->nodes) * sys->nr_nodes);
+	qsort(sys->nodes, sys->nr_nodes, sizeof(*sys->nodes), node_cmp);
+
+	if (sys_can_recover()) {
+		sys->epoch++;
+		update_epoch_store(sys->epoch);
+		update_epoch_log(sys->epoch);
+	}
+	update_vnode_info();
+
 	w = zalloc(sizeof(*w));
 	if (!w)
 		goto oom;
-- 
1.7.7.6