[pve-devel] [PATCH qemu-server] fix #5284: diallow moving vm disks to storages not meant for images

[Filip Schauer]

I tried to move a VM disk from a directory storarge to another directory
storage that does not support the content type 'images'.

```
$ qm disk move 103 efidisk0 local2
400 Parameter verification failed.
storage: storage 'local2' does not support vm images
qm disk move <vmid> <disk> [<storage>] [OPTIONS]
```

As expected, it was prevented.

Trying to move a VM disk to a Proxmox Backup Server now returns a more
fitting error message.

Before the patch:

```
$ qm disk move 103 efidisk0 store1 --delete
create full clone of drive efidisk0 (local:103/vm-103-disk-0.qcow2)
storage migration failed: can't allocate space in pbs storage
```

After the patch:

```
$ qm disk move 103 efidisk0 store1 --delete
400 Parameter verification failed.
storage: storage 'store1' does not support vm images
qm disk move <vmid> <disk> [<storage>] [OPTIONS]
```

PS: The title has a typo: "diallow"

Tested-By: Filip Schauer <f.schauer at proxmox.com>

On 29/08/2024 16:26, Daniel Kral wrote:
> Adds a check if the target storage of a VM disk move between two
> different storages supports the content type 'images'. Without the
> check, it will move the disk image to storages which do not support VM
> images, which causes the VM to fail at startup (for any non-unused
> disks).
>
> Signed-off-by: Daniel Kral <d.kral at proxmox.com>
> ---
> There is a content type check for any used volume (e.g. 'scsi0', ...) at
> PVE/QemuServer.pm:3964 in the subroutine `config_to_command` which will
> (at least) make the VM fail to start unless the volumes are moved to a
> storage that supports images again.
>
> Also, just as a note, moving the disk to storages that do not support
> the `vdisk_alloc` method in the storage plugin (like PBS) also
> rightfully fail before and after this change.
>
>   PVE/API2/Qemu.pm | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/PVE/API2/Qemu.pm b/PVE/API2/Qemu.pm
> index d25a79fe..b6ba9d21 100644
> --- a/PVE/API2/Qemu.pm
> +++ b/PVE/API2/Qemu.pm
> @@ -4409,6 +4409,9 @@ __PACKAGE__->register_method({
>   	    );
>   	} elsif ($storeid) {
>   	    $rpcenv->check($authuser, "/storage/$storeid", ['Datastore.AllocateSpace']);
> +	    my $scfg = PVE::Storage::storage_config($storecfg, $storeid);
> +	    raise_param_exc({ storage => "storage '$storeid' does not support vm images" })
> +		if !$scfg->{content}->{images};
>   
>   	    $load_and_check_move->(); # early checks before forking/locking
>