On Fri 07 Aug 2015 03:03:07 AM CEST, Wen Congyang wrote:
>>> +void bdrv_add_child(BlockDriverState *bs, QDict *options, Error **errp)
>>> +{
>>> +
>>> + if (!bs->drv || !bs->drv->bdrv_add_child) {
>>> + error_setg(errp, "The BDS %s doesn't support adding a child",
>>> + bdrv_get_id_or_node_name(bs));
>>> + return;
>>> + }
>>> +
>>> + bs->drv->bdrv_add_child(bs, options, errp);
>>> +}
>>> +
>>> +void bdrv_del_child(BlockDriverState *bs, BlockDriverState *child_bs,
>>> + Error **errp)
>>> +{
>>> + BdrvChild *child;
>>> +
>>> + if (!bs->drv || !bs->drv->bdrv_del_child) {
>>> + error_setg(errp, "The BDS %s doesn't support removing a child",
>>> + bdrv_get_id_or_node_name(bs));
>>> + return;
>>> + }
>>> +
>>> + QLIST_FOREACH(child, &bs->children, next) {
>>> + if (child->bs == child_bs) {
>>> + break;
>>> + }
>>> + }
>>> +
>>> + if (!child) {
>>> + error_setg(errp, "The BDS %s is not the BDS %s's child",
>>> + bdrv_get_id_or_node_name(child_bs),
>>> + bdrv_get_id_or_node_name(bs));
>>> + return;
>>> + }
>>> +
>>> + bs->drv->bdrv_del_child(bs, child_bs, errp);
>>> +}
>>
>> I see that bdrv_del_child() checks that the child is in bs->children,
>> but who takes care of putting it there in the first place?
>
> The child is opened by the function bdrv_open_image().
> bdrv_open_image()
> bdrv_open_child()
> bdrv_attach_child()
I see, it's drv->bdrv_add_child() who takes care of opening the image,
this only provides the BlockdevOptions.
Thanks!
Reviewed-by: Alberto Garcia <[email protected]>
Berto
