Since 80ccf93b we flush the block device during close. The
bdrv_drain_all() call should come before bdrv_flush() to ensure guest
write requests have completed. Otherwise we may miss pending writes
when flushing.
However, there is still a slight change that cancelling a blockjob or
doing bdrv_flush() might leave an I/O request running, so call
bdrv_drain_all() again for safety as the final step.
Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
---
block.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/block.c b/block.c
index 79ad33d..1c9df27 100644
--- a/block.c
+++ b/block.c
@@ -1357,11 +1357,12 @@ void bdrv_reopen_abort(BDRVReopenState *reopen_state)
void bdrv_close(BlockDriverState *bs)
{
- bdrv_flush(bs);
+ bdrv_drain_all(); /* complete guest I/O */
if (bs->job) {
block_job_cancel_sync(bs->job);
}
- bdrv_drain_all();
+ bdrv_flush(bs);
+ bdrv_drain_all(); /* in case blockjob or flush started I/O */
notifier_list_notify(&bs->close_notifiers, bs);
if (bs->drv) {
--
1.8.1.4
