docs: update documentation for volume clone

after cross-storageclass clone/restore, now we can
clone across different storageclass.
this commit updates the documentation indicating
the same.

Signed-off-by: yati1998 <ypadia@redhat.com>

Documentation/Storage-Configuration/Ceph-CSI/ceph-csi-volume-clone.md

@@ -17,8 +17,16 @@ for more info.
 
 In [pvc-clone](https://github.com/rook/rook/tree/master/deploy/examples/csi/rbd/pvc-clone.yaml),
 `dataSource` should be the name of the `PVC` which is already created by RBD
-CSI driver. The `dataSource` kind should be the `PersistentVolumeClaim` and also storageclass
-should be same as the source `PVC`.
+CSI driver. The `dataSource` kind should be the `PersistentVolumeClaim`.
+The `storageClassName` can be any RBD storageclass (not necessarily same as Parent PVC)
+
+Please note:
+    * `provisioner` must be the same for both the Parent PVC and the Clone PVC.
+    * The non-encrypted PVC cannot be cloned to an encrypted one and vice-versa.
+        * encrypted -> encrypted (possible)
+        * non-encrypted -> non-encrypted (possible)
+        * encrypted -> non-encrypted (not possible)
+        * non-encrypted -> encryptes (not possible)
 
 Create a new PVC Clone from the PVC
 
@@ -55,8 +63,16 @@ kubectl delete -f deploy/examples/csi/rbd/pvc-clone.yaml
 
 In [pvc-clone](https://github.com/rook/rook/tree/master/deploy/examples/csi/cephfs/pvc-clone.yaml),
 `dataSource` should be the name of the `PVC` which is already created by CephFS
-CSI driver. The `dataSource` kind should be the `PersistentVolumeClaim` and also storageclass
-should be same as the source `PVC`.
+CSI driver. The `dataSource` kind should be the `PersistentVolumeClaim`.
+The `storageClassName` can be any CephFS storageclass (not necessarily same as Parent PVC)
+
+Please note:
+    * `provisioner` must be the same for both the Parent PVC and the Clone PVC.
+    * The non-encrypted PVC cannot be cloned to an encrypted one and vice-versa.
+        * encrypted -> encrypted (possible)
+        * non-encrypted -> non-encrypted (possible)
+        * encrypted -> non-encrypted (not possible)
+        * non-encrypted -> encryptes (not possible)
 
 Create a new PVC Clone from the PVC