That sounds like a reasonable option. How far back is the shared disk type supported? As of Icehouse (the oldest supported version I believe), the minimum supported libvirt version is 0.9.6. It would be simpler if it could be a simple change that doesn't have to be if/else'd for different libvirt versions.

On Thu, Mar 19, 2015 at 3:45 AM, Michal Privoznik <mprivozn@redhat.com> wrote:

On 18.03.2015 22:00, Nick Bartos wrote:
> Actually I messed that up slightly on the case. My C is a bit rusty:
>
> diff -U3 -r libvirt-1.2.13.orig/src/qemu/qemu_migration.c
> libvirt-1.2.13/src/qemu/qemu_migration.c
> --- libvirt-1.2.13.orig/src/qemu/qemu_migration.c2015-02-23
> 22:04:12.000000000 -0800
> +++ libvirt-1.2.13/src/qemu/qemu_migration.c2015-03-18
> 13:55:45.873322477 -0700
> @@ -1507,9 +1507,12 @@
> flags |= VIR_STORAGE_VOL_CREATE_PREALLOC_METADATA;
> break;
>
> + case VIR_STORAGE_TYPE_NETWORK:
> + ret = 0;
> + goto cleanup;
> + break;
> case VIR_STORAGE_TYPE_BLOCK:
> case VIR_STORAGE_TYPE_DIR:
> - case VIR_STORAGE_TYPE_NETWORK:
> case VIR_STORAGE_TYPE_NONE:
> case VIR_STORAGE_TYPE_LAST:
> virReportError(VIR_ERR_INTERNAL_ERROR,

Sounds reasonable to me. Although I'm worried that there might be users
using network disk, supplying different XML on migration, where the disk
is switched to yet non-existent network disk, expecting libvirt/qemu to
copy the data.

The other option is: libvirt won't copy shared or read only disks. So
OpenStack would mark network disks as shared.

One way or another - do you want to propose a patch or should I do that?

Michal