block: introduce bdrv_open_file_child() helper

Almost all drivers call bdrv_open_child() similarly. Let's create a
helper for this.

The only not updated drivers that call bdrv_open_child() to set
bs->file are raw-format and snapshot-access:
    raw-format sometimes want to have filtered child but
        don't set drv->is_filter to true.
    snapshot-access wants only 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@yandex-team.ru>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220726201134.924743-3-vsementsov@yandex-team.ru>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2022-07-26 23:11:21 +03:00 committed by Kevin Wolf
parent 046fd84fac
commit 8393078032
24 changed files with 95 additions and 101 deletions

View file

@ -76,6 +76,9 @@ BdrvChild *bdrv_open_child(const char *filename,
const BdrvChildClass *child_class,
BdrvChildRole child_role,
bool allow_none, Error **errp);
int bdrv_open_file_child(const char *filename,
QDict *options, const char *bdref_key,
BlockDriverState *parent, Error **errp);
BlockDriverState *bdrv_open_blockdev_ref(BlockdevRef *ref, Error **errp);
int bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd,
Error **errp);