VDI.data_destroy: reset the VDI's content_id

to a special constant. The content_id of the data_destroyed VDI has to
be different from its old content_id and the content_ids of all the
other VDIs with data, to ensure that we won't select it as the base VDI
during storage motion. Since the data of the VDI has been destroyed, it
should be considered different from all other VDIs that have data.

Signed-off-by: Gabor Igloi <[email protected]>

Author: gaborigloi

ocaml/xapi/storage_access.ml

@@ -844,8 +844,9 @@ module SMAPIv1 = struct
     let disable_cbt context =
       call_cbt_function context ~f:Sm.vdi_disable_cbt ~f_name:"VDI.disable_cbt"
 
-    let data_destroy context =
-      call_cbt_function context ~f:Sm.vdi_data_destroy ~f_name:"VDI.data_destroy"
+    let data_destroy context ~dbg ~sr ~vdi =
+      call_cbt_function context ~f:Sm.vdi_data_destroy ~f_name:"VDI.data_destroy" ~dbg ~sr ~vdi;
+      set_content_id context ~dbg ~sr ~vdi ~content_id:"/No content: this is a cbt_metadata VDI/"
 
     let export_changed_blocks context ~dbg ~sr ~vdi_from ~vdi_to =
       try