From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57395) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a48OA-0006iN-VG for qemu-devel@nongnu.org; Wed, 02 Dec 2015 09:28:16 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a48O5-0000wC-Sv for qemu-devel@nongnu.org; Wed, 02 Dec 2015 09:28:10 -0500 From: Jeff Cody Date: Wed, 2 Dec 2015 09:27:52 -0500 Message-Id: <1449066472-24711-2-git-send-email-jcody@redhat.com> In-Reply-To: <1449066472-24711-1-git-send-email-jcody@redhat.com> References: <1449066472-24711-1-git-send-email-jcody@redhat.com> Subject: [Qemu-devel] [PULL 1/1] mirror: Quiesce source during "mirror_exit" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: peter.maydell@linaro.org, jcody@redhat.com, qemu-devel@nongnu.org From: Fam Zheng 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 --- block/mirror.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/block/mirror.c b/block/mirror.c index 52c9abf..0e8f556 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); } -- 1.9.3