[pve-devel] [PATCH qemu-server 13/14] blockdev: add backing_chain support

DERUMIER, Alexandre alexandre.derumier at groupe-cyllene.com
Wed May 28 11:08:54 CEST 2025


>
>  
> +sub generate_backing_blockdev {

>>make this private?

perl question: how to call a resursive private sub ? (it don't seem to
allow it)



> +    my ($storecfg, $snapshots, $deviceid, $drive, $snap_id) = @_;
> +
> +    my $snapshot = $snapshots->{$snap_id};
> +    my $parentid = $snapshot->{parent};
> +
> +    my $volid = $drive->{file};
> +
> +    my $snap_file_blockdev = generate_file_blockdev($storecfg,
> $drive, $snap_id);
> +    $snap_file_blockdev->{filename} = $snapshot->{file};
> +    $drive->{ro} = 1;
> +    my $snap_fmt_blockdev = generate_format_blockdev($storecfg,
> $drive, $snap_file_blockdev, $snap_id);
> +    $snap_fmt_blockdev->{backing} =
> generate_backing_blockdev($storecfg, $snapshots, $deviceid, $drive,
> $parentid) if $parentid;
> +    return $snap_fmt_blockdev;
> +}
> +
> +sub generate_backing_chain_blockdev {
> +    my ($storecfg, $deviceid, $drive) = @_;
> +
> +    my $volid = $drive->{file};
> +    my $snapshot_type = PVE::Storage::volume_has_feature($storecfg,
> 'snapshot', $volid);
> +    return if !$snapshot_type || $snapshot_type != 3;


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