From: Yunkai Zhang <[email protected]> In old code, corosync driver could not process blocked event correctly.
For example: Suppose there was two requests: R1, R2. 1) In queue_cluster_request(), R1 sent a BLOCK event(B1) to cluster, R1 was added to sys->pending_list. 2) When B1 was received, cdrv_cpg_deliver() was executed, and sd_block_handler() would be called in __dispatch_corosycn_one(). sd_block_handler() will get R1 from sys->pending_list(but not delete R1 from it), cluster_op_running was set TRUE, and then queue_work(). 3) Before cluster_op_done() of R1 was executed, R2 was coming and sent a BLOCK event(B2) to cluster in queue_cluster_request(). 4) Now, cluster_op_done() of R1 was called, R1 sent an UNBLOCK event(U1) to cluster, and cluster_op_running was set FALSE. 5) And then, B2 was received, cdrv_cpg_deliver()->__dispatch_corosycn_one() would be called. Because cluster_op_running was FALSE again, so sd_block_handler() would be executed again, as R1 was also at the head of sys->pending_list, then R1 would be queue_work() again, ..., this bug will lead to so many segment fault. Accord has the same problem, I will fix it in next patch. But zookeeper dirver works well at this situation. Signed-off-by: Yunkai Zhang <[email protected]> --- sheep/cluster/corosync.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/sheep/cluster/corosync.c b/sheep/cluster/corosync.c index bd955bb..7810a2e 100644 --- a/sheep/cluster/corosync.c +++ b/sheep/cluster/corosync.c @@ -38,6 +38,7 @@ static struct cpg_node cpg_nodes[SD_MAX_NODES]; static size_t nr_cpg_nodes; static int self_elect; static int join_finished; +static int corosync_notify_blocked; /* event types which are dispatched in corosync_dispatch() */ enum corosync_event_type { @@ -342,7 +343,8 @@ static int __corosync_dispatch_one(struct corosync_event *cevent) sd_leave_handler(&cevent->sender.ent, entries, nr_cpg_nodes); break; case COROSYNC_EVENT_TYPE_BLOCK: - sd_block_handler(&cevent->sender.ent); + if (sd_block_handler(&cevent->sender.ent)) + corosync_notify_blocked = 1; /* block other messages until the unblock message comes */ return 0; @@ -368,6 +370,14 @@ static void __corosync_dispatch(void) cevent = list_first_entry(&corosync_notify_list, typeof(*cevent), list); + /* + * When there is unfinished blocked event, only cfgchg events + * could continue to be processed(as we have given priotiry to + * process cfgchg events now). + */ + if (!event_is_confchg(cevent->type) && corosync_notify_blocked) + return; + /* update join status */ if (!join_finished) { switch (cevent->type) { @@ -687,6 +697,8 @@ static void corosync_unblock(void *msg, size_t msg_len) { send_message(COROSYNC_MSG_TYPE_UNBLOCK, 0, &this_node, NULL, 0, msg, msg_len); + + corosync_notify_blocked = 0; } static int corosync_notify(void *msg, size_t msg_len) -- 1.7.10.4 -- sheepdog mailing list [email protected] http://lists.wpkg.org/mailman/listinfo/sheepdog
