[PATCH atomic snapshot 4/4] plugin: add optional atomic snapshot creation

[Denis Kanchev]

ping

On Mon, Jun 9, 2025 at 10:32 AM Demayl <denis.kanchev at storpool.com> wrote:

> This will allow creating atomic snapshots from the custom plugins when
> they support it
>
> Signed-off-by: Demayl <denis.kanchev at storpool.com>
> ---
>  src/PVE/Storage.pm        | 52 +++++++++++++++++++++++++++++++++++++--
>  src/PVE/Storage/Plugin.pm | 16 ++++++++++++
>  2 files changed, 66 insertions(+), 2 deletions(-)
>
> diff --git a/src/PVE/Storage.pm b/src/PVE/Storage.pm
> index d0a696a..9b044cc 100755
> --- a/src/PVE/Storage.pm
> +++ b/src/PVE/Storage.pm
> @@ -42,11 +42,11 @@ use PVE::Storage::BTRFSPlugin;
>  use PVE::Storage::ESXiPlugin;
>
>  # Storage API version. Increment it on changes in storage API interface.
> -use constant APIVER => 11;
> +use constant APIVER => 12;
>  # Age is the number of versions we're backward compatible with.
>  # This is like having 'current=APIVER' and age='APIAGE' in libtool,
>  # see
> https://www.gnu.org/software/libtool/manual/html_node/Libtool-versioning.html
> -use constant APIAGE => 2;
> +use constant APIAGE => 3;
>
>  our $KNOWN_EXPORT_FORMATS = ['raw+size', 'tar+size', 'qcow2+size',
> 'vmdk+size', 'zfs', 'btrfs'];
>
> @@ -347,6 +347,54 @@ sub volume_rollback_is_possible {
>      }
>  }
>
> +
> +sub get_volumes_storecfg {
> +    my ($cfg, $volume_data) = @_;
> +    my $vol_cfg = {};
> +    for my $volid (keys %{$volume_data}) {
> +       my ($storeid, $volname) =
> parse_volume_id($volume_data->{$volid}->{file}, 1);
> +       if ($storeid) {
> +           $vol_cfg->{$volname} = {
> +               storeid => $storeid,
> +               scfg => storage_config($cfg, $storeid),
> +           };
> +       }
> +       elsif ($volid =~ m|^(/.+)$| && -e $volid) {
> +           die "snapshot file/device '$volid' is not possible\n";
> +       } else {
> +           die "unable to parse volume ID '$volid'\n";
> +       }
> +    }
> +    return $vol_cfg;
> +}
> +
> +sub volumes_atomic_snapshot_possible {
> +    my ($cfg, $disk_data) = @_;
> +    my $last_type;
> +    my $voldata = get_volumes_storecfg($cfg, $disk_data);
> +    for my $key (keys %$voldata) {
> +       my $type = $voldata->{ $key }->{scfg}->{type};
> +       if (defined($last_type) && $last_type ne $type) {
> +           return (0, 0, $voldata);
> +       }
> +       $last_type = $type;
> +    }
> +    my $plugin = PVE::Storage::Plugin->lookup($last_type);
> +    return (
> +       $plugin->volumes_atomic_snapshot_possible($voldata),
> +       $plugin->atomic_snapshot_preferred($voldata),
> +       $voldata,
> +    )
> +}
> +
> +sub volumes_atomic_snapshot {
> +    my ($voldata, $snapname) = @_;
> +    my $type   = $voldata->{(keys %{$voldata})[0]}->{scfg}->{type};
> +    my $plugin = PVE::Storage::Plugin->lookup($type);
> +
> +    $plugin->volumes_atomic_snapshot($voldata, $snapname);
> +}
> +
>  sub volume_snapshot {
>      my ($cfg, $volid, $snap) = @_;
>
> diff --git a/src/PVE/Storage/Plugin.pm b/src/PVE/Storage/Plugin.pm
> index 4e16420..391dd0b 100644
> --- a/src/PVE/Storage/Plugin.pm
> +++ b/src/PVE/Storage/Plugin.pm
> @@ -1904,4 +1904,20 @@ sub config_aware_base_mkdir {
>      }
>  }
>
> +sub volumes_atomic_snapshot_possible {
> +    my ($class, $voldata) = @_;
> +    return 0;
> +}
> +
> +sub atomic_snapshot_preferred {
> +    my ($class, $volata) = @_;
> +    return 0;
> +}
> +
> +# Performs an atomic (crash-consistent) snapshot of all volumes at once.
> +sub volumes_atomic_snapshot {
> +    my ($class, $voldata, $snap) = @_;
> +    die "volumes_atomic_snapshot is not implemented for $class";
> +}
> +
>  1;
> --
> 2.43.0
>
>

-- 
-- 
*Denis Kanchev*
Senior Software Engineer
StorPool Storage
tel: +3598883395988
@: denis.kanchev at storpool.com
W: www.storpool.com

*The best storage solution when building **a Leading **Cloud.*