Re: [PATCH] xen-block: Fix removal of backend instance via xenstore

[Paolo Bonzini <pbonzini@redhat.com>]

On 08/03/21 19:14, Anthony PERARD wrote:
> On Mon, Mar 08, 2021 at 06:37:38PM +0100, Paolo Bonzini wrote:
>> On 08/03/21 18:29, Anthony PERARD wrote:
>>>> If nothing else works then I guess it's okay, but why can't you do the
>>>> xen_block_drive_destroy from e.g. an unrealize callback?
>>>
>>> I'm not sure if that's possible.
>>>
>>> xen_block_device_create/xen_block_device_destroy() is supposed to be
>>> equivalent to do those qmp commands:
>>>       blockdev-add node-name=xvdz-qcow2 driver=qcow2 file={"driver":"file","filename":"disk.qcow2","locking":"off"}
>>>       device_add id=xvdz driver=xen-disk vdev=xvdz drive=xvdz-qcow2
>>>
>>> But I tried to add a call xen_block_drive_destroy from
>>> xen_block_unrealize, but that still is called too early, it's called
>>> before object_property_del_all() which would delete "drive" and call
>>> release_drive() which would free the node.
>>
>> Can you use blockdev_mark_auto_del?  Then you don't have to call
>> xen_block_drive_destroy at all.
> 
> There is no legacy_dinfo, so blockdev_mark_auto_del doesn't work.

Then I guess it's okay.  Perhaps you can rename the function to 
xen_block_blockdev_destroy so that it's clear it's a blockdev and no 
drive.  Thanks,

Paolo