Re: [PATCH v8 33/34] qcow2: Assert that expand_zero_clusters_in_l1() does not support subclusters

[Eric Blake]

On 6/11/20 8:24 AM, Alberto Garcia wrote:
> On Wed 10 Jun 2020 09:43:53 PM CEST, Eric Blake wrote:
> > On 6/10/20 10:03 AM, Alberto Garcia wrote:
> > > This function is only used by qcow2_expand_zero_clusters() to
> > > downgrade a qcow2 image to a previous version. It is however not
> > > possible to downgrade an image with extended L2 entries because older
> > > versions of qcow2 do not have this feature.
> >
> > Well, it _is_ possible, but it would involve rewriting the entire
> > L1/L2 tables (including all internal snapshots)
>
> Right :-) Let's try this way:
>
>      This function is only used by qcow2_expand_zero_clusters() to
>      downgrade a qcow2 image to a previous version. This would require
>      transforming all extended L2 entries into normal L2 entries but
>      this is not a simple task and there are no plans to implement this
>      at the moment.

Works for me.

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
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