[pve-devel] [PATCH qemu-server 01/13] blockdev: cmdline: add blockdev syntax support

[Fiona Ebner]

Am 03.06.25 um 09:55 schrieb Alexandre Derumier via pve-devel:
> +sub encode_nodename {
> +    my ($type, $volid, $snap) = @_;
> +
> +    my $nodename = "$volid";
> +    $nodename .= "-$snap" if $snap;

This will lead to clashes in some cases:
1. Currently, we allow attaching the same volume multiple times to a
single guest.
2. You can end up with the same name for
volname = vm-1234-disk-0-foo
and for
volname = vm-1234-disk-0, snap = foo

The latter can be rather easily fixed by just using a character we don't
usually support for volume names, but not the former. So I'd like to do
the switch to -blockdev without support for "looking up which node a
certain volume is" at first. In general, I feel like mixing the switch
to -blockdev with your larger series is too much at once. We should
first get the switch to -blockdev completely and cleanly sorted out,
then we can add your external qcow2 support on top.

I think we can even rely on auto-generated-by-QEMU node names at first.
We can later switch to a variant where node names encode additional
information. Or we could also think about patching QEMU to better fit
the need for the "looking up which node a certain volume is" feature.
But I don't think figuring this out should block us right now for the
switch to "-blockdev".

I'll try to work out a series that focuses just on the switch to
"-blockdev" based on your patches during the next week or so. Maybe not
much else needs to be changed :) The work is certainly greatly appreciated!

@Fabian opinions?