Re: [Qemu-devel] [PATCH 3/5] block: support compressed write for copy-on-read

[Max Reitz]

On 2017-11-14 11:16, Anton Nefedov wrote:
> Signed-off-by: Anton Nefedov <address@hidden>
> ---
>  block/io.c         | 30 ++++++++++++++++++++++++------
>  block/trace-events |  2 +-
>  2 files changed, 25 insertions(+), 7 deletions(-)
> 
> diff --git a/block/io.c b/block/io.c
> index 3d5ef2c..93c6b24 100644
> --- a/block/io.c
> +++ b/block/io.c

[...]

> @@ -1209,6 +1220,13 @@ int coroutine_fn bdrv_co_preadv(BdrvChild *child,
>          return ret;
>      }
>  
> +    /* write compressed only makes sense with copy on read */
> +    if ((flags & BDRV_REQ_WRITE_COMPRESSED) &&
> +        !(flags & BDRV_REQ_COPY_ON_READ))
> +    {
> +        return -EINVAL;
> +    }
> +

I think the assertion in bdrv_aligned_preadv() should be enough, but
either way:

Reviewed-by: Max Reitz <address@hidden>

>      bdrv_inc_in_flight(bs);
>  
>      /* Don't do copy-on-read if we read data before write operation */

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