On 12.10.20 19:43, Andrey Shinkevich wrote:
> The 'backing-file' argument is not used by the block-stream job. It
> designates a backing file name to set in QCOW2 image header after the
> block-stream job finished. A backing file name of the node above base
> is used instead.
> 
> Signed-off-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
> ---
>  block/stream.c            |  6 +-----
>  blockdev.c                | 21 ++++++---------------
>  include/block/block_int.h |  2 +-
>  3 files changed, 8 insertions(+), 21 deletions(-)

I don’t think you can deprecate a parameter and effectively remove
support for it in the same release.

Max