Re: [PATCH v7 14/47] stream: Deal with filters

[Andrey Shinkevich]

On 25.06.2020 18:21, Max Reitz wrote:
> Because of the (not so recent anymore) changes that make the stream job
> independent of the base node and instead track the node above it, we
> have to split that "bottom" node into two cases: The bottom COW node,
> and the node directly above the base node (which may be an R/W filter
> or the bottom COW node).
>
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>   qapi/block-core.json |  4 +++
>   block/stream.c       | 63 ++++++++++++++++++++++++++++++++------------
>   blockdev.c           |  4 ++-
>   3 files changed, 53 insertions(+), 18 deletions(-)
>
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index b20332e592..df87855429 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -2486,6 +2486,10 @@
>   # On successful completion the image file is updated to drop the backing file
>   # and the BLOCK_JOB_COMPLETED event is emitted.
>   #
> +# In case @device is a filter node, block-stream modifies the first non-filter
> +# overlay node below it to point to base's backing node (or NULL if @base was

Forgot one thing. To me, it would be more understandable to read

"...to point to the base as backing node..." because it may be thought 
as a backing

node of the base.

Andrey

> +# not specified) instead of modifying @device itself.
> +#
>   # @job-id: identifier for the newly-created block job. If
>   #          omitted, the device name will be used. (Since 2.7)
>   #