[pve-devel] [PATCH qemu-server 1/3] api: clone: always do a full clone of tpmstate volumes

[Fiona Ebner]

Am 12.12.24 um 09:51 schrieb Fabian Grünbichler:
> since there is no reliable way to check whether a linked clone would end up
> being something other than a raw file, and the volumes are tiny anyway.
> 
> otherwise on directory storages, the following sequence of events could happen:
> - linked clone using raw file as base and qcow2 as overlay
> - swtpm_setup interprets qcow2 file as raw
> - swtpm_setup fails to find TPM state and overwrites it with a new one
> - file is now no longer a linked clone, but a raw file with a qcow2 extension
> - move disk and migration fail because of the format mismatch
> 
> the downside is that storages that actually support raw linked clones (ZFS,
> RBD, LVM-thin) now use more space for fully cloned TPM state volumes...
> 
> Signed-off-by: Fabian Grünbichler <f.gruenbichler at proxmox.com>

Reviewed-by: Fiona Ebner <f.ebner at proxmox.com>

> ---
> if we want to avoid the downside, I guess we could do the linked clone, if that
> is not raw, remove it again, and then fallback to full clone?
> 

I prefer the approach in the patch. IMHO, the tpmstate is so small that
it doesn't matter.