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[Qemu-devel] [PATCH v6 13/13] block/mirror: Block "device IO" during mir
From: |
Fam Zheng |
Subject: |
[Qemu-devel] [PATCH v6 13/13] block/mirror: Block "device IO" during mirror exit |
Date: |
Thu, 21 May 2015 14:43:03 +0800 |
When mirror should complete, the source and target are in sync. But we
call bdrv_swap() only a while later in the main loop bh. If the guest
writes something before that, target will not get the new data.
Block "device IO" before bdrv_drain and unblock it after bdrw_swap().
Reported-by: Wen Congyang <address@hidden>
Signed-off-by: Fam Zheng <address@hidden>
---
block/mirror.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/block/mirror.c b/block/mirror.c
index 58f391a..ed770c2 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -320,6 +320,8 @@ static void mirror_drain(MirrorBlockJob *s)
typedef struct {
int ret;
+ /* Use to pause device IO during mirror exit */
+ Error *blocker;
} MirrorExitData;
static void mirror_exit(BlockJob *job, void *opaque)
@@ -358,6 +360,8 @@ static void mirror_exit(BlockJob *job, void *opaque)
if (replace_aio_context) {
aio_context_release(replace_aio_context);
}
+ bdrv_op_unblock(s->common.bs, BLOCK_OP_TYPE_DEVICE_IO, data->blocker);
+ error_free(data->blocker);
g_free(s->replaces);
bdrv_unref(s->target);
block_job_completed(&s->common, data->ret);
@@ -376,6 +380,8 @@ static void coroutine_fn mirror_run(void *opaque)
checking for a NULL string */
int ret = 0;
int n;
+ data = g_malloc0(sizeof(*data));
+ error_setg(&data->blocker, "mirror job exiting");
if (block_job_is_cancelled(&s->common)) {
goto immediate_exit;
@@ -521,6 +527,7 @@ static void coroutine_fn mirror_run(void *opaque)
* mirror_populate runs.
*/
trace_mirror_before_drain(s, cnt);
+ bdrv_op_block(bs, BLOCK_OP_TYPE_DEVICE_IO, data->blocker);
bdrv_drain(bs);
cnt = bdrv_get_dirty_count(s->dirty_bitmap);
}
@@ -543,6 +550,7 @@ static void coroutine_fn mirror_run(void *opaque)
s->common.cancelled = false;
break;
}
+ bdrv_op_unblock(bs, BLOCK_OP_TYPE_DEVICE_IO, data->blocker);
last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
}
@@ -563,7 +571,6 @@ immediate_exit:
bdrv_release_dirty_bitmap(bs, s->dirty_bitmap);
bdrv_iostatus_disable(s->target);
- data = g_malloc(sizeof(*data));
data->ret = ret;
block_job_defer_to_main_loop(&s->common, mirror_exit, data);
}
--
2.4.1
- [Qemu-devel] [PATCH v6 09/13] blockdev: Block device IO during external snapshot transaction, (continued)
- [Qemu-devel] [PATCH v6 13/13] block/mirror: Block "device IO" during mirror exit,
Fam Zheng <=