[libvirt] [RFC] Add flag for virsh undefine to remove/wipe the disk devices

Hi, All I'm thinking to introduce a new flag (something like --remove-disks, --wipe-disks) for "virsh undefine", so that the user can choose whether to remove/wipe the disk devices or not, have seen this requirement in many places, @libvirt-users, public #virt, and also we have a bug of this function. So, IMHO this is a reasonable requirement, following is the rough thoughts: 1) General idea. As we don't have a API which can get all the disk devices of a domain, perhaps need to write functions to parse domain xml to extract the disks' path (this is annoyed, but seems don't other way), and then lookup them by storage volume API (virStorageVolLookupByPath), and then can remove or wipe the volume by (virStorageVolDelete/virStorageVolWipe). And for the disk path which doesn't belong to any storage pool, simply remove it by "unlink()"? 2) Which type of devices can not be removed/wiped. * Can't delete/wipe ISCSI/SCSI vol. * Vol doesn't exists (which will throw an warning when do virStorageVolLookupByPath). * Have no write permission on the parent directory of the disk path. * Can't delete/wipe the disk device which is passthrough'ed from host, (e.g. /dev/sr0 as a CDROM device for guest) * The storage pool which the disk device belongs to as a vol is marked as "share" * The storage pool which the disk device belongs as a vol is readonly * can't delete disk device of network type. * Any others? For these situations, we need to do checking and throw straightforward warnings to tell user why it can't be removed/wiped. Any idea is welcomed. Thanks. CC'ed Eric, as I saw you talked about this somewhere. (#virt?), :-) Regards Osier