[pve-devel] [PATCH storage v3 1/4] btrfs: add helper to iterate over snapshots of a subvolume

[Fiona Ebner]

Am 19.02.25 um 10:58 schrieb Maximiliano Sandoval:
> In this context a subvolume means a BTRFS subvolume.
> `$volume\@$snap_name` would be for example
> `btrfs_volume/images/102/vm-102-disk-0 at snap_name`.
> 
> Signed-off-by: Maximiliano Sandoval <m.sandoval at proxmox.com>
> ---
> 
> Differences from v2:
>  - Split into multiple commits
>  - Simplify patch
>  - Use only the snapshot name in the callback of the helper
> 
> Differences from v1:
>  - Add a helper to run callback on each snapshot.
> 
>  src/PVE/Storage/BTRFSPlugin.pm | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/src/PVE/Storage/BTRFSPlugin.pm b/src/PVE/Storage/BTRFSPlugin.pm
> index cadd9d1..43f797a 100644
> --- a/src/PVE/Storage/BTRFSPlugin.pm
> +++ b/src/PVE/Storage/BTRFSPlugin.pm
> @@ -419,6 +419,20 @@ my sub foreach_subvol : prototype($$) {
>      })
>  }
>  
> +# Calls `$code->($volume, $snap_name)` for each snapshot of the BTRFS subvolume.
> +my sub foreach_snapshot_of_subvol : prototype($$) {
> +    my ($subvol, $code) = @_;
> +
> +    my $basename = basename($subvol);
> +    my $dir = dirname($subvol);
> +    foreach_subvol($dir, sub {

We're getting there, but:

This helper still is named incorrectly. I'd like to have the helper and
the regex be named correctly (not your fault, but it just gets more
confusing if there are more users). You can change the helper to only
operate on a given subvolume, because that is the only use case we have.
I.e. merge your wrapper and the original helper.

I'd also name it foreach_snapshot_of_subvolume() to better differentiate
it from the 'subvol' format, and path_is_subvolume() already uses the
word 'subvolume'.

> +	my ($volume, $name, $snap) = @_;
> +	return if $name ne $basename;
> +	return if !defined $snap;
> +	$code->($snap);
> +   });
> +}
> +
>  sub free_image {
>      my ($class, $storeid, $scfg, $volname, $isBase, $_format) = @_;
>