[libvirt] [PATCH] introducing <source> <name> (for logical storage pools)

Hi Folks - This small patch is a proposed prerequisite for the storage pool discovery patch I submitted last week. Daniel B proposed having storage pool discovery return a bunch of XML storage <source> elements, rather than full <pool> elements (which contain "target-dependent" details like the local pool name and device or mount path -- things which don't need to be decided unless/until the pool is defined). I like his suggestion a lot, and I think it addresses the final API-definition problem keeping storage pool discovery out of libvirt. But ... it doesn't quite work for logical storage pools because those are created from the <pool> <name> element (which is the same as the volume group name). This patch introduces a new <source> element <name>, which is distinct from the pool name. <name> is used only by the logical storage backend, and represents the volume group name. For convenience and back-compatibility, <source> <name> defaults to the pool name if not specified when the pool is defined, and <pool> <name> defaults to the source name if not specified. There is no requirement that pool and source name be the same, though. While admittedly it seems a little weird, it does allow more flexibility (pool name not tied to vol group name), and allows <source> to fully specify a logical pool source, as it does for the other pool types[*]. Defaulting the source name from the pool name means all existing pool XML definitions continue to work. Defaulting the pool name from the source name is simply a matter of convenience (but perhaps a step too far?) If this is accepted, logical pool discovery can then return a bunch of sources like: <source><name>VolGroup00</name></source> <source><name>VolGroup01</name></source> Please note I'll be on vacation next week (Aug 11-15), so I may not be responding until the following week. Thanks, Dave [*] Well ... almost. Note that directory pools have a similar issue -- the "source" of the pool is given by the <target> <path> -- there's no <source>. I suppose implementing directory pool discovery (for the sake of completeness) means addressing this as well, maybe via some similar mechanism ...