Re: [Qemu-block] [PATCH] block: all I/O should be completed before removing throttle timers.

[Alberto Garcia]

On Sat 21 Oct 2017 07:34:00 AM CEST, Zhengui Li wrote:
> From: Zhengui <address@hidden>
>
> In blk_remove_bs, all I/O should be completed before removing throttle
> timers. If there has inflight I/O, removing throttle timers here will
> cause the inflight I/O never return.
> This patch add bdrv_drained_begin before throttle_timers_detach_aio_context
> to let all I/O completed before removing throttle timers.
>
> Signed-off-by: Zhengui <address@hidden>
> ---
>  block/block-backend.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/block/block-backend.c b/block/block-backend.c
> index 45d9101..9edc452 100644
> --- a/block/block-backend.c
> +++ b/block/block-backend.c
> @@ -660,7 +660,11 @@ void blk_remove_bs(BlockBackend *blk)
>      notifier_list_notify(&blk->remove_bs_notifiers, blk);
>      if (blk->public.throttle_group_member.throttle_state) {
>          tt = &blk->public.throttle_group_member.throttle_timers;
> +        BlockDriverState *bs;
> +        bs = blk_bs(blk);
> +        bdrv_drained_begin(bs);
>          throttle_timers_detach_aio_context(tt);
> +        bdrv_drained_end(bs);

You can keep my R-b, but seeing this in context I think you should
define BlockDriverState either at the beginning of the block or together
with ThrottleTimers at the beginning of the function.

Berto