Re: [PATCH v5 02/45] block: introduce bdrv_open_file_child() helper

[Hanna Reitz]

On 30.03.22 23:28, Vladimir Sementsov-Ogievskiy wrote:
> Almost all drivers call bdrv_open_child() similarly. Let's create a
> helper for this.
>
> The only not updated driver that call bdrv_open_child() to set
> bs->file is raw-format, as it sometimes want to have filtered child but
> don't set drv->is_filter to true.

Also snapshot-access, which uses DATA | PRIMARY.

> Possibly we should implement drv->is_filter_func() handler, to consider
> raw-format as filter when it works as filter.. But it's another story.
>
> Note also, that we decrease assignments to bs->file in code: it helps
> us restrict modifying this field in further commit.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@openvz.org>
> ---

[...]

> diff --git a/block/filter-compress.c b/block/filter-compress.c
> index d5be538619..b2cfa9a9a5 100644
> --- a/block/filter-compress.c
> +++ b/block/filter-compress.c
> @@ -30,10 +30,8 @@
>   static int compress_open(BlockDriverState *bs, QDict *options, int flags,
>                            Error **errp)
>   {
> -    bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
> -                               BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
> -                               false, errp);
> -    if (!bs->file) {
> +    int ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
> +    if (ret < 0) {
>           return -EINVAL;

Should probably be `return ret;` like elsewhere.

With that done:

Reviewed-by: Hanna Reitz <hreitz@redhat.com>