Re: [Qemu-devel] [PATCH 2/3] block/backup: disable copy_range for compressed backup

[John Snow <jsnow@redhat.com>]

On 7/30/19 12:32 PM, Vladimir Sementsov-Ogievskiy wrote:
> Enabled by default copy_range ignores compress option. It's definitely
> unexpected for user.
> 
> It's broken since introduction of copy_range usage in backup in
> 9ded4a011496.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  block/backup.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/block/backup.c b/block/backup.c
> index f4aaf08df3..c5f941101a 100644
> --- a/block/backup.c
> +++ b/block/backup.c
> @@ -645,7 +645,7 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
>      job->cluster_size = cluster_size;
>      job->copy_bitmap = copy_bitmap;
>      copy_bitmap = NULL;
> -    job->use_copy_range = true;
> +    job->use_copy_range = !compress; /* compression isn't supported for it */
>      job->copy_range_size = MIN_NON_ZERO(blk_get_max_transfer(job->common.blk),
>                                          blk_get_max_transfer(job->target));
>      job->copy_range_size = MAX(job->cluster_size,
> 

Agree, these aren't compatible options. Is this worth a note in
docs/interop/live-block-operations.rst?

Reviewed-by: John Snow <jsnow@redhat.com>