[pve-devel] [PATCH-SERIES v3 pve-storage/qemu-server/pve-qemu] add external qcow2 snapshot support

[Fiona Ebner]

Am 13.01.25 um 11:06 schrieb Fiona Ebner:
> Am 10.01.25 um 13:30 schrieb DERUMIER, Alexandre:
>> blockdev-reopen don't work with autogenerated nodenames (block#<id>)
>> (not sure if it's a bug or not).
>> That's why I'm currently naming all of them (including backing chain
>> snapshots too)
> 
> Hmm, sounds like it might a bug, I can look into it. If really required
> to make it work, we can still set fixed node-names on the commandline,
> but also query them before usage to be sure we have the correct, i.e.
> currently inserted node.

AFAICT, this is because the node name is not set in the original options
for the block driver state and then it wrongly detects an attempt to
change the node name (even if specifying the correct auto-generated one
during reopen). However, it is rather ugly to try and use a -drive
together with blockdev-reopen in any case, blockdev-reopen is really
written with -blockdev in mind and -blockdev necessarily requires
setting node-name up front.

I don't think it's even worth fixing that bug. We should use
blockdev-reopen only after switching to -blockdev, it's much nicer like
that :)

I'd still be in favor of querying the node-name of drives with
query-block before doing QMP operations though. Like that, we can
warn/error if it doesn't match what we expect for example, to catch
unexpected situations.