Re: [Qemu-devel] [PATCH V9 03/11] quorum: Add quorum_aio_writev and its dependencies.

[Max Reitz <mreitz@redhat.com>]

On 2013-10-02 14:39, Benoît Canet wrote:
> Signed-off-by: Benoit Canet <benoit@irqsave.net>
> ---
>   block/quorum.c | 123 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 123 insertions(+)
>
> diff --git a/block/quorum.c b/block/quorum.c
> index 9557e61..b49e3c6 100644
> --- a/block/quorum.c
> +++ b/block/quorum.c
> @@ -64,11 +64,134 @@ struct QuorumAIOCB {
>       int vote_ret;
>   };
>   
> +static void quorum_aio_cancel(BlockDriverAIOCB *blockacb)
> +{
> +    QuorumAIOCB *acb = container_of(blockacb, QuorumAIOCB, common);
> +    bool finished = false;
> +
> +    /* Wait for the request to finish */
> +    acb->finished = &finished;
> +    while (!finished) {
> +        qemu_aio_wait();
> +    }
Hm, wouldn't it be better to pass the cancel to the children?

Max

> +}
> +
> +static AIOCBInfo quorum_aiocb_info = {
> +    .aiocb_size         = sizeof(QuorumAIOCB),
> +    .cancel             = quorum_aio_cancel,
> +};
> +
> +/* return the first error code get by each individual callbacks */
> +static int quorum_get_first_error(QuorumAIOCB *acb)
> +{
> +    BDRVQuorumState *s = acb->bqs;
> +    int i, ret = 0;
> +
> +    for (i = 0; i < s->total; i++) {
> +        ret = acb->aios[i].ret;
> +        if (ret) {
> +            return ret;
> +        }
> +    }
> +
> +    /* should not pass here */
> +    assert(false);
> +}
> +
> +static void quorum_aio_finalize(QuorumAIOCB *acb)
> +{
> +    BDRVQuorumState *s = acb->bqs;
> +    int ret;
> +
> +    ret = s->threshold <= acb->success_count ? 0 : quorum_get_first_error(acb);
> +
> +    acb->common.cb(acb->common.opaque, ret);
> +    if (acb->finished) {
> +        *acb->finished = true;
> +    }
> +    g_free(acb->aios);
> +    qemu_aio_release(acb);
> +}
> +
> +static QuorumAIOCB *quorum_aio_get(BDRVQuorumState *s,
> +                                   BlockDriverState *bs,
> +                                   QEMUIOVector *qiov,
> +                                   uint64_t sector_num,
> +                                   int nb_sectors,
> +                                   BlockDriverCompletionFunc *cb,
> +                                   void *opaque)
> +{
> +    QuorumAIOCB *acb = qemu_aio_get(&quorum_aiocb_info, bs, cb, opaque);
> +    int i;
> +
> +    acb->bqs = s;
> +    acb->sector_num = sector_num;
> +    acb->nb_sectors = nb_sectors;
> +    acb->qiov = qiov;
> +    acb->aios = g_new0(QuorumSingleAIOCB, s->total);
> +    acb->count = 0;
> +    acb->success_count = 0;
> +    acb->finished = NULL;
> +    acb->is_read = false;
> +    acb->vote_ret = 0;
> +
> +    for (i = 0; i < s->total; i++) {
> +        acb->aios[i].buf = NULL;
> +        acb->aios[i].ret = 0;
> +        acb->aios[i].parent = acb;
> +    }
> +
> +    return acb;
> +}
> +
> +static void quorum_aio_cb(void *opaque, int ret)
> +{
> +    QuorumSingleAIOCB *sacb = opaque;
> +    QuorumAIOCB *acb = sacb->parent;
> +    BDRVQuorumState *s = acb->bqs;
> +
> +    sacb->ret = ret;
> +    acb->count++;
> +    if (ret == 0) {
> +        acb->success_count++;
> +    }
> +    assert(acb->count <= s->total);
> +    assert(acb->success_count <= s->total);
> +    if (acb->count < s->total) {
> +        return;
> +    }
> +
> +    quorum_aio_finalize(acb);
> +}
> +
> +static BlockDriverAIOCB *quorum_aio_writev(BlockDriverState *bs,
> +                                          int64_t sector_num,
> +                                          QEMUIOVector *qiov,
> +                                          int nb_sectors,
> +                                          BlockDriverCompletionFunc *cb,
> +                                          void *opaque)
> +{
> +    BDRVQuorumState *s = bs->opaque;
> +    QuorumAIOCB *acb = quorum_aio_get(s, bs, qiov, sector_num, nb_sectors,
> +                                      cb, opaque);
> +    int i;
> +
> +    for (i = 0; i < s->total; i++) {
> +        acb->aios[i].aiocb = bdrv_aio_writev(&s->bs[i], sector_num, qiov,
> +                                             nb_sectors, &quorum_aio_cb,
> +                                             &acb->aios[i]);
> +    }
> +
> +    return &acb->common;
> +}
> +
>   static BlockDriver bdrv_quorum = {
>       .format_name        = "quorum",
>       .protocol_name      = "quorum",
>   
>       .instance_size      = sizeof(BDRVQuorumState),
> +
> +    .bdrv_aio_writev    = quorum_aio_writev,
>   };
>   
>   static void bdrv_quorum_init(void)