[PATCH 4/4] backup: Allow configuring incremental backup per-disk individually

[Eric Blake]

On 7/7/20 10:23 AM, Peter Krempa wrote:
> The semantics of the backup operation don't strictly require that all
> disks being backed up are part of the same incremental part (when a disk
> was checkpointed/backed up separately or in a different VM), or even
> they may not have an previous checkpoint at all (e.g. when the disk

s/an/a/

> was freshly hotplugged to the vm).
> 
> In such cases we can still create a common checkpoint for all of them
> and backup differences according to configuration.
> 
> This patch adds a per-disk configuration of the checkpoint to do the
> incremental backup from via the 'incremental' attribute and allows
> perform full backups via the 'backupmode' attribute.
> 
> Note that no changes to the qemu driver are necessary to take advantage
> of this as we already obey the per-disk 'incremental' field.
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1829829
> 
> Signed-off-by: Peter Krempa <pkrempa at redhat.com>
> ---
> v2:
>      - backupmode=full incremental="..." is now rejected by the RNG
>        schema
>      - test output changes as we now validate virDomainBackupAlignDisks
>      - typo fix
> 
Reviewed-by: Eric Blake <eblake at redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org