add storage_has_feature() helper function

Which looks up whether a storage supports a given feature in its
'plugindata'. This is intentionally kept simple and not implemented
as a plugin method for now. Should it ever become more complex
requiring plugins to override the default implementation, it can
later be changed to a method.

Suggested-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
Tested-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
Reviewed-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
Link: https://lore.proxmox.com/20250404133204.239783-3-f.ebner@proxmox.com

src/PVE/Storage.pm

@@ -213,6 +213,14 @@ sub storage_check_enabled {
     return storage_check_node($cfg, $storeid, $node, $noerr);
 }
 
+sub storage_has_feature {
+    my ($cfg, $storeid, $feature) = @_;
+
+    my $scfg = storage_config($cfg, $storeid);
+
+    return PVE::Storage::Plugin::storage_has_feature($scfg->{type}, $feature);
+}
+
 # storage_can_replicate:
 # return true if storage supports replication
 # (volumes allocated with vdisk_alloc() has replication feature)

src/PVE/Storage/Plugin.pm

@@ -245,6 +245,16 @@ sub dirs_hash_to_string {
     return join(',', map { "$_=$hash->{$_}" } sort keys %$hash);
 }
 
+sub storage_has_feature {
+    my ($type, $feature) = @_;
+
+    my $data = $defaultData->{plugindata}->{$type};
+    if (my $features = $data->{features}) {
+	return $features->{$feature};
+    }
+    return;
+}
+
 sub default_format {
     my ($scfg) = @_;