Re: [PATCH v3 pve-qemu qemu-server 0/6] bypass host page cache for restore on zvol

[Christian Ebner <c.ebner@proxmox.com>]

On 8/20/26 2:07 PM, Thomas Lamprecht wrote:
> On 20/08/2026 11:56, Lukas Sichert wrote:
>> On 2026-08-20 11:05, Christian Ebner <c.ebner@proxmox.com> wrote:
>>
>>> This patch series skips writing to the host page cache for restores
>>> to zvols, with the intention to avoid potential I/O delay issues for
>>> other ZFS-backed VMs during page writeback on certain setups, as
>>> reported in enterprise support and reproduced internally.
>>>
>>> This patch series adds an optional no-cache parameter for pbs-restore
>>> command invocation, setting the BDRV_O_NOCACHE flag for the block
>>> device being restored to and sets `cache=none` for vma restores.
>>
>> When I test patched debs on my testmachines I normally bump the version
>> with a local<x> suffigx. package_name_1.2.3 is deployed as
>> package_name_1.2.3+local1. When starting a restore with this and v2, I got
>> the error 'TASK ERROR: internal error: cannot check version of invalid
>> string 'unknown' at /usr/share/perl5/PVE/QemuServer/Helpers.pm line 104.'
>>
>> Christian proposed the following diff off-list, which worked for me.
>>
>> diff --git a/src/PVE/QemuServer/Helpers.pm b/src/PVE/QemuServer/Helpers.pm
>> index 5065a457..1ed48a3b 100644
>> --- a/src/PVE/QemuServer/Helpers.pm
>> +++ b/src/PVE/QemuServer/Helpers.pm
>> @@ -68,7 +68,7 @@ sub kvm_user_version {
>>       $kvm_mtime->{$binary} = $st->mtime;
>>
>>       my $binary_version_re = qr/(\d+\.\d+(\.\d+)?)(\.\d+)?/;
>> -    my $package_version_re = qr/\(pve-qemu-kvm_(\d+\.\d+(\.\d+)?-\d+)\)/;
>> +    my $package_version_re = qr/\(pve-qemu-kvm_(\d+\.\d+(\.\d+)?-\d+)(\+[a-zA-Z0-9]+)?\)/;
>>
>>       my $code = sub {
>>           my $line = shift;
>>
>> I wouldn't consider this a blocker, but it would be a nice to have in a
>> potential next version.
> 
> 
> meh, that's far from great - re-implementing all off debians
> package version seems also futile and hard to maintain; so either
> we use "dpkg --compare-versions ..." directly via run_command or
> just bump the versioned dependency in d/control here - even though
> the latter makes downgrading slightly more work, it is IMO still more
> preferable for this here, and it would allow us to drop like three
> patches FWICT.

Okay, will drop the 3 version check helper patches then and bump the 
dependency instead for v4.

Thanks!