Re: [Qemu-devel] [PATCH v3 09/10] sheepdog: cancel aio requests if possible

[Liu Yuan <namei.unix@gmail.com>]

On Thu, Jul 25, 2013 at 05:32:04PM +0900, MORITA Kazutaka wrote:
> This patch tries to cancel aio requests in pending queue and failed
> queue.  When the sheepdog driver cannot cancel the requests, it waits
> for them to be completed.
> 
> Signed-off-by: MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>
> ---
>  block/sheepdog.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++---------
>  1 file changed, 59 insertions(+), 11 deletions(-)
> 
> diff --git a/block/sheepdog.c b/block/sheepdog.c
> index 9f3fa89..7bf882a 100644
> --- a/block/sheepdog.c
> +++ b/block/sheepdog.c
> @@ -294,7 +294,8 @@ struct SheepdogAIOCB {
>      Coroutine *coroutine;
>      void (*aio_done_func)(SheepdogAIOCB *);
>  
> -    bool canceled;
> +    bool cancelable;
> +    bool *finished;
>      int nr_pending;
>  };
>  
> @@ -411,6 +412,7 @@ static inline void free_aio_req(BDRVSheepdogState *s, AIOReq *aio_req)
>  {
>      SheepdogAIOCB *acb = aio_req->aiocb;
>  
> +    acb->cancelable = false;
>      QLIST_REMOVE(aio_req, aio_siblings);
>      g_free(aio_req);
>  
> @@ -419,23 +421,68 @@ static inline void free_aio_req(BDRVSheepdogState *s, AIOReq *aio_req)
>  
>  static void coroutine_fn sd_finish_aiocb(SheepdogAIOCB *acb)
>  {
> -    if (!acb->canceled) {
> -        qemu_coroutine_enter(acb->coroutine, NULL);
> +    qemu_coroutine_enter(acb->coroutine, NULL);
> +    if (acb->finished) {
> +        *acb->finished = true;
>      }
>      qemu_aio_release(acb);
>  }
>  
> +/*
> + * Check whether the specified acb can be canceled
> + *
> + * We can cancel aio when any request belonging to the acb is:
> + *  - Not processed by the sheepdog server.
> + *  - Not linked to the inflight queue.
> + */
> +static bool sd_acb_cancelable(const SheepdogAIOCB *acb)
> +{
> +    BDRVSheepdogState *s = acb->common.bs->opaque;
> +    AIOReq *aioreq;
> +
> +    if (!acb->cancelable) {
> +        return false;
> +    }
> +
> +    QLIST_FOREACH(aioreq, &s->inflight_aio_head, aio_siblings) {
> +        if (aioreq->aiocb == acb) {
> +            return false;
> +        }
> +    }
> +
> +    return false;

return true; ?

> +}

Thanks
Yuan