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[Qemu-block] [PATCH] mirror: Quiesce source during "mirror_exit"
From: |
Fam Zheng |
Subject: |
[Qemu-block] [PATCH] mirror: Quiesce source during "mirror_exit" |
Date: |
Mon, 23 Nov 2015 10:28:04 +0800 |
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 <address@hidden>
---
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);
}
--
2.4.3
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