On 08/06/2015 10:33 PM, Alberto Garcia wrote:
> On Fri 31 Jul 2015 11:19:12 AM CEST, Wen Congyang wrote:
>
>> +/*
>> + * Hot add/remove a BDS's child. So the user can take a child offline when
>> + * it is broken and take a new child online
>> + */
>> +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()
Thanks
Wen Congyang
>
> Berto
> .
>
