Cloning between storage classes (same backend) not possible since v25.06.1

[boris-dockter-itk]

Describe the bug
If cloning across different storage classes (even on the same backend) there is the error "clone volume %s from source volume %s with different storage classes is not allowed".

Source code
Original issue: #987
Changes: v25.06.0...v25.06.1
Commit: 57499ff: "clone volume %s from source volume %s with different storage classes is not allowed"

Environment

• Trident version: 25.06.3
• Kubernetes version: 1.28.15
• Kubernetes orchestrator: Rancher v2.9.3

To reproduce

• Choose two different storage classes on the same backend.
• Clone a volume from storage class a to storage class b.

Expected behavior

• Cloning between different storage classes should be allowed if both storage classes belong to the same backend. ERROR only if both storage class AND backend are different.
• Alternative: There should be a setting regarding the cloning between different storage classes on the same backend: "errorIfCloningBetweenStorageClasses": Default value: True > ERROR; False > WARNING

Background

• We are using the backup tool "Veeam Kasten". When exporting volumes it uses a temporary persistent volume claim during the process.
• We also use two storage classes with the reclaim policies "retain" and "delete" on the same backend.
• After the clone process the no more needed persistent volume claim gets removed. But if the original volumes' reclaim policy has been "retain" the no more needed persistent volume stays.
• Currently (Trident 25.06.3)
  • it's not possible to use a storage class with "delete" for the temporary persistent volume claim if the original storage class has "retain"
  • the reclaim policy from the temporary persistent volume has to be changed manually to "delete" to get it removed.