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

On Wed, Mar 30, 2011 at 09:39:14PM +0800, Osier Yang wrote: > 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()"? Won't work for connection to remote hosts. > 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. I would rather make this a flag of virDomainUndefine(), except there is no flag argument for it :(