[pve-devel] [PATCH v2 qemu-server] fix #4201: delete cloud-init disk on rollback

[Stefan Hanreich]

Test Setup:
I created a new VM, without any Cloud-Init drive, and immediately 
created a snapshot. Then I setup a Cloud-Init drive according to the PVE 
documentation via CLI. I created another snapshot of this state with a 
Cloud-Init drive.

What I tested:
- Rolling back to the older snapshot without Cloud-Init drive, it got 
successfully removed.
- Rolling back to the newer snapshot that includes a Cloud-Init drive, 
it successfully showed up afterwards.

I also tested both of those cases with Cloud-Init drives created from 
the Web UI, in case there are any differences.

Some additional tests including normal CD-ROM drives I did as well - 
just in case:
- Rolled back from a snapshot with only a Cloud-Init drive to a snapshot 
that contains only a CD-ROM drive, the CD-ROM drive showed up afterwards 
and removed the Cloud-Init drive successfully
- Rolled back from a snapshot with only a CD-ROM drive to a state that 
contains only a Cloud-Init drive, the Cloud-Init drive showed up 
afterwards and removed the CD-ROM drive successfully


Code LGTM


Reviewed-by: Stefan Hanreich <s.hanreich at proxmox.com>
Tested-by: Stefan Hanreich <s.hanreich at proxmox.com>

On 10/20/22 17:22, Mira Limbeck wrote:
> If the config doesn't contain the cloud-init disk anymore after the
> rollback, we have to clean it up since otherwise no further disk can be
> attached unless the one still existing on the storage is deleted.
>
> Signed-off-by: Mira Limbeck <m.limbeck at proxmox.com>
> ---
> v2:
>   - chose the add_unused_volume way as @fiona recommended, the
>     implementation is a lot cleaner, but contains a cloudinit regex
>
>   - removed the 2nd patch for reusing already existing disks when
>     adding a cloudinit disk
>
>   PVE/QemuConfig.pm | 17 +++++++++++++++--
>   1 file changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/PVE/QemuConfig.pm b/PVE/QemuConfig.pm
> index 482c7ab..9fb8e9f 100644
> --- a/PVE/QemuConfig.pm
> +++ b/PVE/QemuConfig.pm
> @@ -498,7 +498,7 @@ sub __snapshot_rollback_get_unused {
>       $class->foreach_volume($conf, sub {
>   	my ($vs, $volume) = @_;
>   
> -	return if PVE::QemuServer::drive_is_cdrom($volume);
> +	return if PVE::QemuServer::drive_is_cdrom($volume, 1);
>   
>   	my $found = 0;
>   	my $volid = $volume->{file};
> @@ -507,7 +507,7 @@ sub __snapshot_rollback_get_unused {
>   	    my ($ds, $drive) = @_;
>   
>   	    return if $found;
> -	    return if PVE::QemuServer::drive_is_cdrom($drive);
> +	    return if PVE::QemuServer::drive_is_cdrom($drive, 1);
>   
>   	    $found = 1
>   		if ($drive->{file} && $drive->{file} eq $volid);
> @@ -519,6 +519,19 @@ sub __snapshot_rollback_get_unused {
>       return $unused;
>   }
>   
> +sub add_unused_volume {
> +    my ($class, $config, $volid) = @_;
> +
> +    if ($volid =~ m/vm-\d+-cloudinit/) {
> +	print "found unused cloudinit disk '$volid', removing it\n";
> +	my $storecfg = PVE::Storage::config();
> +	PVE::Storage::vdisk_free($storecfg, $volid);
> +	return undef;
> +    } else {
> +        return $class->SUPER::add_unused_volume($config, $volid);
> +    }
> +}
> +
>   # END implemented abstract methods from PVE::AbstractConfig
>   
>   sub has_cloudinit {