Re: [Qemu-devel] [PATCH] block/quorum: implement .bdrv_co_get_block_status

[Paolo Bonzini <pbonzini@redhat.com>]

Il 17/07/2014 13:50, Liu Yuan ha scritto:
> - allow drive-mirror to create sprase mirror on images like qcow2
> - allow qemu-img map to work as expected on quorum driver
> 
> Cc: Benoit Canet <benoit@irqsave.net>
> Cc: Kevin Wolf <kwolf@redhat.com>
> Cc: Stefan Hajnoczi <stefanha@redhat.com>
> Signed-off-by: Liu Yuan <namei.unix@gmail.com>
> ---
>  block/quorum.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/block/quorum.c b/block/quorum.c
> index ebf5c71..f0d0a98 100644
> --- a/block/quorum.c
> +++ b/block/quorum.c
> @@ -780,6 +780,21 @@ static coroutine_fn int quorum_co_flush(BlockDriverState *bs)
>      return result;
>  }
>  
> +static int64_t coroutine_fn quorum_co_get_block_status(BlockDriverState *bs,
> +                                                       int64_t sector_num,
> +                                                       int nb_sectors,
> +                                                       int *pnum)
> +{
> +    BDRVQuorumState *s = bs->opaque;
> +    BlockDriverState *child_bs = s->bs[0];
> +
> +    if (child_bs->drv->bdrv_co_get_block_status)
> +        return child_bs->drv->bdrv_co_get_block_status(child_bs, sector_num,
> +                                                       nb_sectors, pnum);

Is this "if" necessary?

> +    return bdrv_get_block_status(child_bs, sector_num, nb_sectors, pnum);

Also, the definition of BDRV_BLOCK_OFFSET_VALID explicitly refers to
bs->file, so you probably have to exclude it from the result as well as
BDRV_BLOCK_RAW.

Paolo

> +
>  static bool quorum_recurse_is_first_non_filter(BlockDriverState *bs,
>                                                 BlockDriverState *candidate)
>  {
> @@ -1038,6 +1053,7 @@ static BlockDriver bdrv_quorum = {
>      .bdrv_close                         = quorum_close,
>  
>      .bdrv_co_flush_to_disk              = quorum_co_flush,
> +    .bdrv_co_get_block_status           = quorum_co_get_block_status,
>  
>      .bdrv_getlength                     = quorum_getlength,
>  
>