CA-260245: Fix SXM: old host choking on new op (2)

When populating VDI.allowed_operations, consider only the operations
that existed before the Ely release (corresponding to XenServer 7.1).
(Ely contained the first additions since 2009 or earlier.)

(The previous commit marked CA-260245 was insufficient to fix the SXM.)

Signed-off-by: Thomas Sanders <[email protected]>

Author: thomassa

ocaml/xapi/xapi_globs.ml

@@ -454,7 +454,10 @@ let rpu_allowed_vm_operations = [
   `update_allowed_operations;
 ]
 
-let rpu_allowed_vdi_operations = [
+(* Until the Ely release, the vdi_operations enum had stayed unchanged
+ * since 2009 or earlier, but then Ely and some subsequent releases
+ * added new members to the enum. *)
+let pre_ely_vdi_operations = [
   `clone;
   `copy;
   `resize;
@@ -468,6 +471,9 @@ let rpu_allowed_vdi_operations = [
   `blocked;
 ]
 
+(* We might consider restricting this further. *)
+let rpu_allowed_vdi_operations = pre_ely_vdi_operations
+
 (* Viridian key name (goes in platform flags) *)
 let viridian_key_name = "viridian"
 (* Viridian key value (set in new templates, in built-in templates on upgrade and when Orlando PV drivers up-to-date first detected) *)

ocaml/xapi/xapi_vdi.ml

@@ -253,11 +253,23 @@ let update_allowed_operations_internal ~__context ~self ~sr_records ~pbd_records
   let pool = Helpers.get_pool ~__context in
   let ha_enabled = Db.Pool.get_ha_enabled ~__context ~self:pool in
 
+  (* CA-260245: older XenServer versions do not know about newer operations,
+   * and therefore cannot do storage migration to a XenServer that lists them
+   * in a VDI's allowed_operations field.
+   * As a temporary measure, we are fixing the symptom by excluding newer ops
+   * from the allowed_operations list. This is a hack: TECHNICAL DEBT.
+   * We would prefer to do a more general fix for this class of problems with
+   * no age-based exclusion of VDI operations from allowed_operations.
+   * We have one or two approaches in mind.
+   * If/when we do this, we can update test_vdi_allowed_operations.ml to
+   * re-enable (and maybe alter) the relevant part of
+   * test_update_allowed_operations.
+   *)
   let all_ops = Listext.List.set_difference
     (* Older XenServers choke on ops they don't recognise during SXM, so
-     * filter out the recently added ones: CA-260245 *)
-    Xapi_vdi_helpers.all_ops
-    (`blocked :: Xapi_vdi_helpers.recently_added_ops)
+     * until we have a better solution we consider only old ones: CA-260245 *)
+    Xapi_globs.pre_ely_vdi_operations
+    [`blocked]
   in
   let all = Db.VDI.get_record_internal ~__context ~self in
   let allowed =

ocaml/xapi/xapi_vdi_helpers.ml

@@ -24,42 +24,6 @@ open Threadext
 module D=Debug.Make(struct let name="xapi" end)
 open D
 
-let all_ops: API.vdi_operations list =
-  [ `blocked
-  ; `clone
-  ; `copy
-  ; `destroy
-  ; `disable_cbt
-  ; `enable_cbt
-  ; `force_unlock
-  ; `forget
-  ; `generate_config
-  ; `mirror
-  ; `resize
-  ; `resize_online
-  ; `set_on_boot
-  ; `snapshot
-  ; `update
-  ]
-
-(* CA-260245: older XenServer versions do not know about these operations,
- * and therefore cannot do storage migration to a XenServer that lists them
- * in a VDI's allowed_operations field.
- * As a temporary measure, we are fixing the symptom by excluding these ops
- * from the allowed_operations list. This is a hack: TECHNICAL DEBT.
- * If we were to continue with this mechanism then any additional new ops would
- * have to be added to this recently_added_ops list, and we would be able to
- * remove items when old-but-supported XenServer versions know about them.
- * We would prefer to do a more general fix for this class of problems; we have
- * one or two approaches in mind. *)
-let recently_added_ops: API.vdi_operations list =
-  (* If/when items are removed from this list, update
-   * test_vdi_allowed_operations.ml to re-enable (and maybe alter)
-   * the relevant part of test_update_allowed_operations. *)
-  [ `enable_cbt
-  ; `disable_cbt
-  ]
-
 (* CA-26514: Block operations on 'unmanaged' VDIs *)
 let assert_managed ~__context ~vdi =
   if not (Db.VDI.get_managed ~__context ~self:vdi)