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mirror: use bdrv_drained_begin/bdrv_drained_end

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Ensure that there are no changes between the last check to
bdrv_get_dirty_count and the switch to the target.

There is already a bdrv_drained_end call, we only need to ensure
that bdrv_drained_begin is not called twice.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-Id: <1477565348-5458-4-git-send-email-pbonzini@redhat.com>
Signed-off-by: Fam Zheng <famz@redhat.com>
This commit is contained in:
Paolo Bonzini 2016-10-27 12:48:51 +02:00 committed by Fam Zheng
parent bae8196d9f
commit 9a0cec664e
1 changed files with 23 additions and 12 deletions
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35
block/mirror.c
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@ -622,6 +622,7 @@ static void coroutine_fn mirror_run(void *opaque)
MirrorExitData *data;
BlockDriverState *bs = blk_bs(s->common.blk);
BlockDriverState *target_bs = blk_bs(s->target);
bool need_drain = true;
int64_t length;
BlockDriverInfo bdi;
char backing_filename[2]; /* we only need 2 characters because we are only
@ -757,11 +758,26 @@ static void coroutine_fn mirror_run(void *opaque)
* source has dirty data to copy!
*
* Note that I/O can be submitted by the guest while
* mirror_populate runs.
* mirror_populate runs, so pause it now. Before deciding
* whether to switch to target check one last time if I/O has
* come in the meanwhile, and if not flush the data to disk.
*/
trace_mirror_before_drain(s, cnt);
bdrv_co_drain(bs);
bdrv_drained_begin(bs);
cnt = bdrv_get_dirty_count(s->dirty_bitmap);
if (cnt > 0) {
bdrv_drained_end(bs);
continue;
}
/* The two disks are in sync. Exit and report successful
* completion.
*/
assert(QLIST_EMPTY(&bs->tracked_requests));
s->common.cancelled = false;
need_drain = false;
break;
}
ret = 0;
@ -774,13 +790,6 @@ static void coroutine_fn mirror_run(void *opaque)
} else if (!should_complete) {
delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0);
block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns);
} else if (cnt == 0) {
/* The two disks are in sync. Exit and report successful
* completion.
*/
assert(QLIST_EMPTY(&bs->tracked_requests));
s->common.cancelled = false;
break;
}
s->last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
}
@ -792,6 +801,7 @@ immediate_exit:
* the target is a copy of the source.
*/
assert(ret < 0 || (!s->synced && block_job_is_cancelled(&s->common)));
assert(need_drain);
mirror_wait_for_all_io(s);
}
@ -804,9 +814,10 @@ 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(bs);
if (need_drain) {
bdrv_drained_begin(bs);
}
block_job_defer_to_main_loop(&s->common, mirror_exit, data);
}