[libvirt] [PATCH] conf: fix backing store parse off-by-one

[Jiri Denemark]

On Wed, May 21, 2014 at 22:06:08 -0600, Eric Blake wrote:
> Commit 546154e parses the type attribute from a <backingStore>
> element, but forgot that the earlier commit 9673418 added a
> placeholder element in the same 1.2.3 release; as a result,
> the C code was mistakenly allowing "none" as a type.
> 
> Similarly, the same commit allows "none" as the <format>
> sub-element type, even though that has been a placeholder
> since the 0.10.2 release with commit f772b3d.
> 
> * src/conf/domain_conf.c (virDomainDiskBackingStoreParse): Require
> non-zero types.
> 
> Signed-off-by: Eric Blake <eblake at redhat.com>
> 
> ---
> Maybe worth addressing in a later patch: the RelaxNG grammar
> currently requires a <format> and <backingStore> subelement
> to any non-empty <backingStore>, and the C code matches this
> requirement.  However, we should probably make both of them
> optional, to represent the case where the user is requesting
> that we perform a probe to complete the backing chain details.

Right, however, this change will only make sense when we actually add
support for user-supplied backing chains so implementing this part
earlier is useless and perhaps even confusing.

ACK

Jirka