[libvirt] RFCv2: virDomainSnapshotCreateXML enhancements

[Eric Blake]

On 08/11/2011 08:36 PM, Eric Blake wrote:
> In implementing this in virsh, I found that for backwards compatibility
> reasons, it would be easier to two flags instead of one, since both use
> cases seem plausible (do the bare minimum to remove my domain, but
> wihtout losing snapshot data, vs. nuke everything including my snapshot
> data that was associated with the domain). Hence I'm modifying this
> slightly to be:
>
> VIR_DOMAIN_UNDEFINE_SNAPSHOTS_FULL -> maps to
> virDomainSnapshotDelete(,0), can be emulated on older servers
> VIR_DOMAIN_UNDEFINE_SNAPSHOTS_METADATA -> maps to
> virDomainSnapshotDelete(,VIR_DOMAIN_SNAPSHOT_DELETE_METADATA_ONLY),
> cannot be simulated with server older than 0.9.5

And to make it easier to detect whether a domain has libvirt snapshot 
metadata, I need to add:

virDomainSnapshotNum(,VIR_DOMAIN_SNAPSHOT_NUM_METADATA)

For ESX and Vbox, where snapshot relationships are reconstructed on the 
fly from information always available outside of libvirt, there is no 
libvirt metadata to delete, and the presence of snapshots does not 
interfere with domain undefines, so the new flag will return 0.  But for 
qemu, where libvirt stores the relationships, the new flag will return 
the same as passing flags=0.

-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org