From 176c36997fd4a94a7b919468d8967e0ad81fdf9c Mon Sep 17 00:00:00 2001 From: Fam Zheng Date: Mon, 23 Nov 2015 10:28:04 +0800 Subject: [PATCH] mirror: Quiesce source during "mirror_exit" With dataplane, the ioeventfd events could be dispatched after mirror_run releases the dirty bitmap, but before mirror_exit actually does the device switch, because the iothread will still be running, and it will cause silent data loss. Fix this by adding a bdrv_drained_begin/end pair around the window, so that no new external request will be handled. Signed-off-by: Fam Zheng Signed-off-by: Jeff Cody --- block/mirror.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/block/mirror.c b/block/mirror.c index 52c9abfe14..0e8f5565a5 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -388,6 +388,7 @@ static void mirror_exit(BlockJob *job, void *opaque) bdrv_unref(s->target); block_job_completed(&s->common, data->ret); g_free(data); + bdrv_drained_end(src); bdrv_unref(src); } @@ -607,6 +608,9 @@ immediate_exit: data = g_malloc(sizeof(*data)); data->ret = ret; + /* Before we switch to target in mirror_exit, make sure data doesn't + * change. */ + bdrv_drained_begin(s->common.bs); block_job_defer_to_main_loop(&s->common, mirror_exit, data); } -- 2.11.4.GIT