Il 10/06/2013 10:38, Stefan Hajnoczi ha scritto:
> On Mon, Jun 10, 2013 at 02:25:57PM +0200, Stefan Hajnoczi wrote:
>> @@ -1427,26 +1456,18 @@ void bdrv_close_all(void)
>> void bdrv_drain_all(void)
>> {
>> BlockDriverState *bs;
>> - bool busy;
>> -
>> - do {
>> - busy = qemu_aio_wait();
>>
>> + while (bdrv_requests_pending_all()) {
>> /* FIXME: We do not have timer support here, so this is effectively
>> * a busy wait.
>> */
>> QTAILQ_FOREACH(bs, &bdrv_states, list) {
>> if (!qemu_co_queue_empty(&bs->throttled_reqs)) {
>> qemu_co_queue_restart_all(&bs->throttled_reqs);
>> - busy = true;
>> }
>> }
>> - } while (busy);
>>
>> - /* If requests are still pending there is a bug somewhere */
>> - QTAILQ_FOREACH(bs, &bdrv_states, list) {
>> - assert(QLIST_EMPTY(&bs->tracked_requests));
>> - assert(qemu_co_queue_empty(&bs->throttled_reqs));
>> + qemu_aio_wait();
>> }
>> }
>
> tests/ide-test found an issue here: block.c invokes callbacks from a BH
> so we may not yet have completed the request when this loop terminates.
>
> Kevin: can you fold in this patch?
>
> diff --git a/block.c b/block.c
> index 31f7231..e176215 100644
> --- a/block.c
> +++ b/block.c
> @@ -1469,6 +1469,9 @@ void bdrv_drain_all(void)
>
> qemu_aio_wait();
> }
> +
> + /* Process pending completion BHs */
> + aio_poll(qemu_get_aio_context(), false);
> }
aio_poll could require multiple iterations, this is why the old code was
starting with "busy = qemu_aio_wait()". You can add a while loop around
the new call, or do something more similar to the old code, along the
lines of "do { QTAILQ_FOREACH(...) ...; busy =
bdrv_request_pending_all(); busy |= aio_poll(qemu_get_aio_context(),
busy); } while(busy);".
