On 07/04/2017 04:44 AM, Kevin Wolf wrote: > Am 04.07.2017 um 10:40 hat Manos Pitsidianakis geschrieben: >> The following functions fail if bs->drv does not implement them: >>
>> @@ -511,6 +513,8 @@ int bdrv_probe_geometry(BlockDriverState *bs, HDGeometry
>> *geo)
>>
>> if (drv && drv->bdrv_probe_geometry) {
>> return drv->bdrv_probe_geometry(bs, geo);
>> + } else if (drv && bs->file && bs->file->bs) {
>> + return bdrv_probe_geometry(bs->file->bs, geo);
>> }
>>
>> return -ENOTSUP;
>
> The probed geometry would refer to the physical image file, not to the
> actually presented image. So propagating this to bs->file is wrong for
> image formats.
>
> Possibly checking .is_filter in addition would be enough.
In fact, this made me think: if we define .is_filter as an enum instead
of a bool, we could implement 0 for no filter, 1 for file filter, and 2
for backing filter. Then instead of having to have 2 separate default
bdrv_get_block_status_for_*() generic functions in patch 4, we could
instead patch bdrv_co_get_block_status() to check .is_filter, and
automatically fall back to bs->file or bs->backing according to the enum
value stored in .is_filter.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
signature.asc
Description: OpenPGP digital signature
