Re: [PATCH v2 25/33] block: Make filter drivers use child_of_bds

[Eric Blake]

On 2/4/20 11:08 AM, Max Reitz wrote:
> Note that some filters have secondary children, namely blkverify (the
> image to be verified) and blklogwrites (the log).  This patch does not
> touch those children.

I would have guessed blkdebug; but I guess that's not quite a filter for 
other reasons, so it gets covered in a later patch.

> Note that for blkverify, the filtered child should not be format-probed.
> While there is nothing enforcing this here, in practice, it will not be:
> blkverify implements .bdrv_file_open.  The block layer ensures (and in
> fact, asserts) that BDRV_O_PROTOCOL is set for every BDS whose driver
> implements .bdrv_file_open.  This flag will then be bequeathed to
> blkverify's children, and they will thus (by default) not be probed
> either.
>
> ("By default" refers to the fact that blkverify's other child (the
> non-filtered one) will have BDRV_O_PROTOCOL force-unset, because that is
> what happens for all non-filtered children of non-format drivers.)
>
> Signed-off-by: Max Reitz <address@hidden>
> ---
>   block/blkdebug.c        | 4 +++-
>   block/blklogwrites.c    | 3 ++-
>   block/blkverify.c       | 4 +++-
>   block/copy-on-read.c    | 5 +++--
>   block/filter-compress.c | 5 +++--
>   block/replication.c     | 3 ++-
>   block/throttle.c        | 5 +++--
>   7 files changed, 19 insertions(+), 10 deletions(-)

Reviewed-by: Eric Blake <address@hidden>

--
Eric Blake, Principal Software Engineer
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