Re: [Qemu-devel] [PATCH 16/20] qemu-img: call aio_context_acquire/release around block job

[Fam Zheng <famz@redhat.com>]

On Mon, 10/17 15:54, Paolo Bonzini wrote:
> This will be needed by bdrv_reopen_multiple, which calls
> bdrv_drain_all and thus will *release* the AioContext.

Looks okay, but I wonder how bdrv_drain_all releasing AioContext break anything?

Fam

> 
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>         v1->v2: new [qemu-iotests]
> 
>  qemu-img.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/qemu-img.c b/qemu-img.c
> index 02c07b9..ad7c964 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -795,6 +795,7 @@ static void run_block_job(BlockJob *job, Error **errp)
>  {
>      AioContext *aio_context = blk_get_aio_context(job->blk);
>  
> +    aio_context_acquire(aio_context);
>      do {
>          aio_poll(aio_context, true);
>          qemu_progress_print(job->len ?
> @@ -802,6 +803,7 @@ static void run_block_job(BlockJob *job, Error **errp)
>      } while (!job->ready);
>  
>      block_job_complete_sync(job, errp);
> +    aio_context_release(aio_context);
>  
>      /* A block job may finish instantaneously without publishing any progress,
>       * so just signal completion here */
> @@ -819,6 +821,7 @@ static int img_commit(int argc, char **argv)
>      Error *local_err = NULL;
>      CommonBlockJobCBInfo cbi;
>      bool image_opts = false;
> +    AioContext *aio_context;
>  
>      fmt = NULL;
>      cache = BDRV_DEFAULT_CACHE;
> @@ -928,8 +931,11 @@ static int img_commit(int argc, char **argv)
>          .bs   = bs,
>      };
>  
> +    aio_context = bdrv_get_aio_context(bs);
> +    aio_context_acquire(aio_context);
>      commit_active_start("commit", bs, base_bs, 0, BLOCKDEV_ON_ERROR_REPORT,
>                          common_block_job_cb, &cbi, &local_err, false);
> +    aio_context_release(aio_context);
>      if (local_err) {
>          goto done;
>      }
> -- 
> 2.7.4
> 
>