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Re: [Qemu-block] [PATCH for-2.5 3/6] Add new block driver interface to a
From: |
Alberto Garcia |
Subject: |
Re: [Qemu-block] [PATCH for-2.5 3/6] Add new block driver interface to add/delete a BDS's child |
Date: |
Fri, 07 Aug 2015 13:52:04 +0200 |
User-agent: |
Notmuch/0.13.2 (http://notmuchmail.org) Emacs/23.2.1 (i486-pc-linux-gnu) |
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 <address@hidden>
Berto