Re: [PATCH v11 1/2] docs: improve qcow2 spec about extending image header

[Eric Blake]

On 1/31/20 8:22 AM, Vladimir Sementsov-Ogievskiy wrote:
> Make it more obvious how to add new fields to the version 3 header and
> how to interpret them.
>
> The specification is adjusted so that for new defined optional fields:
>
> 1. Software may support some of these optional fields and ignore the
>     others, which means that features may be backported to downstream
>     Qemu independently.
> 2. If we want to add incompatible field (or a field, for which some its

s/some/some of/

>     values would be incompatible), it must be accompanied by
>     incompatible feature bit.
>
> Also the concept of "default is zero" is clarified, as it's strange to
> say that the value of the field is assumed to be zero for the software
> version which don't know about the field at all and don't know how to
> treat it be it zero or not.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> Reviewed-by: Eric Blake <address@hidden>
> ---
>   docs/interop/qcow2.txt | 45 +++++++++++++++++++++++++++++++++++++++---
>   1 file changed, 42 insertions(+), 3 deletions(-)
--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org