Re: [libvirt] [RFC PATCHv2 4/n] snapshot: actually compute branch definition from XML

When asked to parse a branch snapshot XML definition, we have to piece together the definition of the new snapshot from parts of the branch point, as well as run some sanity checks that the branches are compatible. This patch is rather restrictive in what it allows; depending on effort and future needs, we may be able to relax some of those restrictions and allow more cases.

+ if (other) { + /* For now, we only allow branch snapshots of external snapshots. */ + if (virDomainSnapshotAlignDisks(def, + VIR_DOMAIN_SNAPSHOT_LOCATION_EXTERNAL, + true) < 0) + goto cleanup; + for (i = 0; i < def->ndisks; def++)