[PATCH pve-storage v1 12/54] plugin: use closure for inner loop logic in list_volumes

["Max R. Carrara" <m.carrara@proxmox.com>]

Factor most of the body of the inner loop of the `list_volumes()`
plugin API method into a closure and provide additional context for
why we have such an elaborate check for VM / CT disks in the first
place.

This has the added benefit that we now also do not modify the volume
hashes on the fly anymore when determining whether a volume's type
aligns with a guest's type. Small difference, but might make it a
little easier to adapt that code in the future, e.g. when we align
vtypes and content types.

Also, rename `$item` to `$volume` for clarity's sake.

Signed-off-by: Max R. Carrara <m.carrara@proxmox.com>
---
 src/PVE/Storage/Plugin.pm | 49 +++++++++++++++++++++++++--------------
 1 file changed, 32 insertions(+), 17 deletions(-)

diff --git a/src/PVE/Storage/Plugin.pm b/src/PVE/Storage/Plugin.pm
index 106cff6f..c96c1ed7 100644
--- a/src/PVE/Storage/Plugin.pm
+++ b/src/PVE/Storage/Plugin.pm
@@ -1820,29 +1820,44 @@ sub list_volumes {
         return;
     };

+    my $get_content_type_for_volume = sub {
+        my ($volume, $type) = @_;
+
+        # It is currently impossible to determine whether a volume belongs to a
+        # VM or a CT based on the output of list_images alone.
+        # Therefore, we use the parsed ID ($volume->{vmid}) to look up the guest
+        # and make sure that the guest's type corresponds to the volume's type.
+        if ($type eq 'images' || $type eq 'rootdir') {
+            my $vminfo = $vmlist->{ids}->{ $volume->{vmid} };
+
+            my $vmtype;
+            if (defined($vminfo)) {
+                $vmtype = $vminfo->{type};
+            }
+
+            my $content_type = 'images';
+            if (defined($vmtype) && $vmtype eq 'lxc') {
+                $content_type = 'rootdir';
+            }
+
+            return if $content_type ne $type;
+        }
+
+        return $type;
+    };
+
     for my $type ($content_types->@*) {
         my $raw_volumes = $get_raw_volumes_for_type->($type);

         next if !defined($raw_volumes);

-        for my $item ($raw_volumes->@*) {
-            if ($type eq 'images' || $type eq 'rootdir') {
-                my $vminfo = $vmlist->{ids}->{ $item->{vmid} };
-                my $vmtype;
-                if (defined($vminfo)) {
-                    $vmtype = $vminfo->{type};
-                }
-                if (defined($vmtype) && $vmtype eq 'lxc') {
-                    $item->{content} = 'rootdir';
-                } else {
-                    $item->{content} = 'images';
-                }
-                next if $type ne $item->{content};
-            } else {
-                $item->{content} = $type;
-            }
+        for my $volume ($raw_volumes->@*) {
+            my $content_type = $get_content_type_for_volume->($volume, $type);

-            push $res->@*, $item;
+            next if !defined($content_type);
+
+            $volume->{content} = $content_type;
+            push $res->@*, $volume;
         }
     }

--
2.47.3