Re: [Qemu-devel] [PATCH v5 07/42] block: *filtered_cow_child() for *has_zero_init()

[Vladimir Sementsov-Ogievskiy]

13.06.2019 1:09, Max Reitz wrote:
> bdrv_has_zero_init() and the related bdrv_unallocated_blocks_are_zero()
> should use bdrv_filtered_cow_child() if they want to check whether the
> given BDS has a COW backing file.
> 
> Signed-off-by: Max Reitz <address@hidden>
> ---
>   block.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/block.c b/block.c
> index be18130944..64d6190984 100644
> --- a/block.c
> +++ b/block.c
> @@ -4933,7 +4933,7 @@ int bdrv_has_zero_init(BlockDriverState *bs)
>   
>       /* If BS is a copy on write image, it is initialized to
>          the contents of the base image, which may not be zeroes.  */
> -    if (bs->backing) {
> +    if (bdrv_filtered_cow_child(bs)) {
>           return 0;
>       }

Hmm, if you are fixing bdrv_has_zero_init around filters, I'd prefere to fix 
the whole
function, converting the following here too:
     if (bs->file && bs->drv->is_filter) {
         return bdrv_has_zero_init(bs->file->bs);
     }


But it's not a real problem:

Reviewed-by: Vladimir Sementsov-Ogievskiy <address@hidden>

>       if (bs->drv->bdrv_has_zero_init) {
> @@ -4951,7 +4951,7 @@ bool bdrv_unallocated_blocks_are_zero(BlockDriverState 
> *bs)
>   {
>       BlockDriverInfo bdi;
>   
> -    if (bs->backing) {
> +    if (bdrv_filtered_cow_child(bs)) {
>           return false;
>       }
>   
> 


-- 
Best regards,
Vladimir