On 29.10.2015 14:00, Alberto Garcia wrote:
> There are several sanity checks for the 'blockdev-snapshot' command,
> but none covers the use of a file BDS as the overlay node.
>
> { 'execute': 'blockdev-add', 'arguments':
> { 'options': { 'driver': 'qcow2',
> 'node-name': 'new0',
> 'file': { 'driver': 'file',
> 'filename': 'new.qcow2',
> 'node-name': 'file0' } } } }
>
> { 'execute': 'blockdev-snapshot', 'arguments':
> { 'node': 'virtio0',
> 'overlay': 'file0' } }Well, I don't think the problem here is that file0 has a parent. For instance, you might want to use a qcow2 child node of a quorum BDS as the new overlay; or in the future, you may want to use a snapshot node which has some filters on top of it. To me, the problem is that file0 is driven by the driver "file" which does not support backing files. I think that's what should be fixed. Max > This series fixes that and adds a new test case. This of course > depends on the 'blockdev-snapshot' series: > > https://lists.gnu.org/archive/html/qemu-block/2015-10/msg00974.html > > I anyway wonder if it wouldn't be a good idea to have regular op > blockers in all file BDSs? > > Regards, > > Berto > > Alberto Garcia (2): > block: Don't allow snapshots if the overlay has parent nodes > block: test 'blockdev-snapshot' using a file BDS as the overlay > > blockdev.c | 5 +++++ > tests/qemu-iotests/085 | 12 +++++++++++- > tests/qemu-iotests/085.out | 4 ++++ > 3 files changed, 20 insertions(+), 1 deletion(-) >
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