fix: Fix recreate check for formats without labelling support

Formats like LUKS or LVMPV don't support labels so we need to skip
the label check in BlivetVolume._reformat.

Resolves: RHEL-29874

library/blivet.py

@@ -826,6 +826,9 @@ def _reformat(self):
         if ((fmt is None and self._device.format.type is None)
                 or (fmt is not None and self._device.format.type == fmt.type)):
             # format is the same, no need to run reformatting
+            if not hasattr(self._device.format, "label"):
+                # not all formats support labels
+                return
             dev_label = '' if self._device.format.label is None else self._device.format.label
             if dev_label != fmt.label:
                 # ...but the label has changed - schedule modification action

tests/tests_volume_relabel.yml

@@ -111,6 +111,26 @@
     - name: Verify role results
       include_tasks: verify-role-results.yml
 
+    - name: Format the device to LVMPV which doesn't support labels
+      include_role:
+        name: linux-system-roles.storage
+      vars:
+        storage_volumes:
+          - name: test1
+            type: disk
+            fs_type: lvmpv
+            disks: "{{ unused_disks }}"
+
+    - name: Rerun to check we don't try to relabel preexisitng LVMPV (regression test for RHEL-29874)
+      include_role:
+        name: linux-system-roles.storage
+      vars:
+        storage_volumes:
+          - name: test1
+            type: disk
+            fs_type: lvmpv
+            disks: "{{ unused_disks }}"
+
     - name: Clean up
       include_role:
         name: linux-system-roles.storage