Re: [pve-devel] [PATCH pve-storage 09/13] storage: add volume_support_qemu_snapshot

["DERUMIER, Alexandre via pve-devel" <pve-devel@lists.proxmox.com>]

[-- Attachment #1: Type: message/rfc822, Size: 16281 bytes --]

From: "DERUMIER, Alexandre" <alexandre.derumier@groupe-cyllene.com>
To: "w.bumiller@proxmox.com" <w.bumiller@proxmox.com>
Cc: "pve-devel@lists.proxmox.com" <pve-devel@lists.proxmox.com>, "t.lamprecht@proxmox.com" <t.lamprecht@proxmox.com>, "f.gruenbichler@proxmox.com" <f.gruenbichler@proxmox.com>
Subject: Re: [pve-devel] [PATCH pve-storage 09/13] storage: add volume_support_qemu_snapshot
Date: Tue, 15 Jul 2025 15:38:57 +0000
Message-ID: <82c18a632e730b7c18a93aacd9f4d623d56061be.camel@groupe-cyllene.com>

>>Yeah I tried some quick tests and it seems to be a bit tricky. Or
>>maybe
>>I just missed something.

Just have done fast tests, I think I have found a way. 
(I'll do more test tomorrow to see if everything is ok in guest)



sub qemu_volume_snapshot {
    my ($vmid, $deviceid, $storecfg, $drive, $snap) = @_;
.....

    } elsif ($do_snapshots_type eq 'external') {
        my $storeid = (PVE::Storage::parse_volume_id($volid))[0];
        my $scfg = PVE::Storage::storage_config($storecfg, $storeid);
        print "external qemu snapshot\n";
        my $snapshots = PVE::Storage::volume_snapshot_info($storecfg,
$volid);
        my $parent_snap = $snapshots->{'current'}->{parent};
        my $machine_version =
PVE::QemuServer::Machine::get_current_qemu_machine($vmid);

#no rename here anymore

            PVE::QemuServer::Blockdev::blockdev_external_snapshot(
                $storecfg, $vmid, $machine_version, $deviceid, $drive,
$snap, $parent_snap
            );
...
}


sub blockdev_external_snapshot {
    my ($storecfg, $vmid, $machine_version, $deviceid, $drive, $snap,
$parent_snap) = @_;

    print "Creating a new current volume with $snap as backing snap\n";

    my $volid = $drive->{file};

    #rename current to snap && preallocate add a new current file with
reference to snapbacking-file, we can remove the $running param

    my $running = undef
    PVE::Storage::volume_snapshot($storecfg, $volid, $snap, undef);

    #call the blockdev_rename, only to reopen internal blockdev current
active image to snap volname

    my $skip_volume_rename=1;
    #reopen current to snap    
     PVE::QemuServer::Blockdev::blockdev_rename(
            $storecfg,
            $vmid,
            $machine_version,
            $deviceid,
            $drive,   
            'current',
            $snap,
            $parent_snap,
            $skip_volume_rename
     );

    ###the rest is the same than before

    #be sure to add drive in write mode
    delete($drive->{ro});

    my $new_file_blockdev = generate_file_blockdev($storecfg, $drive);
    my $new_fmt_blockdev = generate_format_blockdev($storecfg, $drive,
$new_file_blockdev);

    my $snap_file_blockdev = generate_file_blockdev($storecfg, $drive,
$snap);
    my $snap_fmt_blockdev = generate_format_blockdev(
        $storecfg,
        $drive,
        $snap_file_blockdev,
        { 'snapshot-name' => $snap },
    );


    #backing need to be forced to undef in blockdev, to avoid reopen of
backing-file on blockdev-add
    $new_fmt_blockdev->{backing} = undef;

    mon_cmd($vmid, 'blockdev-add', %$new_fmt_blockdev);

    mon_cmd(
        $vmid, 'blockdev-snapshot',
        node => $snap_fmt_blockdev->{'node-name'},
        overlay => $new_fmt_blockdev->{'node-name'},
    );
}

[-- Attachment #2: Type: text/plain, Size: 160 bytes --]

_______________________________________________
pve-devel mailing list
pve-devel@lists.proxmox.com
https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel