Fix use of elevated context for resize methods

elevated contexts were being passed over RPC to confirm_resize,
revert_resize, and finish_revert_resize methods.  If those methods need
to elevate context, they should do so themselves.

There was 1 case (when deleting an instance in RESIZED) when we'd send a
non-elevated context to confirm_resize().  This would fail because the
migration_get() call there requires admin context and confirm_resize()
on the manager side did not elevate the context itself.

This fixes bug 1071600 and removes sending elevated contexts for these
methods over RPC.

(Ultimately we need some work to make the migration* DB API calls verify
project_id vs requiring admin context..)

Change-Id: I907889502f19fba8059253e52dca084a123016e2

2 files changed, 21 insertions, 19 deletions

diff --git a/nova/compute/api.py b/nova/compute/api.py
index 0e5a6568e..7a05ab3d7 100644
--- a/nova/compute/api.py
+++ b/nova/compute/api.py
@@ -1504,8 +1504,8 @@ class API(base.Base):
     @check_instance_state(vm_state=[vm_states.RESIZED])
     def revert_resize(self, context, instance):
         """Reverts a resize, deleting the 'new' instance in the process."""
-        context = context.elevated()
-        migration_ref = self.db.migration_get_by_instance_and_status(context,
+        elevated = context.elevated()
+        migration_ref = self.db.migration_get_by_instance_and_status(elevated,
                 instance['uuid'], 'finished')
 
         # reverse quota reservation for increased resource usage
@@ -1520,7 +1520,7 @@ class API(base.Base):
                 instance=instance, migration_id=migration_ref['id'],
                 host=migration_ref['dest_compute'], reservations=reservations)
 
-        self.db.migration_update(context, migration_ref['id'],
+        self.db.migration_update(elevated, migration_ref['id'],
                                  {'status': 'reverted'})
 
     @wrap_check_policy
@@ -1528,8 +1528,8 @@ class API(base.Base):
     @check_instance_state(vm_state=[vm_states.RESIZED])
     def confirm_resize(self, context, instance):
         """Confirms a migration/resize and deletes the 'old' instance."""
-        context = context.elevated()
-        migration_ref = self.db.migration_get_by_instance_and_status(context,
+        elevated = context.elevated()
+        migration_ref = self.db.migration_get_by_instance_and_status(elevated,
                 instance['uuid'], 'finished')
 
         # reserve quota only for any decrease in resource usage
@@ -1545,7 +1545,7 @@ class API(base.Base):
                 host=migration_ref['source_compute'],
                 reservations=reservations)
 
-        self.db.migration_update(context, migration_ref['id'],
+        self.db.migration_update(elevated, migration_ref['id'],
                 {'status': 'confirmed'})
 
     @staticmethod
diff --git a/nova/compute/manager.py b/nova/compute/manager.py
index af183625e..13b9f2d2a 100644
--- a/nova/compute/manager.py
+++ b/nova/compute/manager.py
@@ -1440,7 +1440,8 @@ class ComputeManager(manager.SchedulerDependentManager):
                        migration=None, migration_id=None):
         """Destroys the source instance."""
         if not migration:
-            migration = self.db.migration_get(context, migration_id)
+            migration = self.db.migration_get(context.elevated(),
+                    migration_id)
 
         self._notify_about_instance_usage(context, instance,
                                           "resize.confirm.start")
@@ -1472,8 +1473,8 @@ class ComputeManager(manager.SchedulerDependentManager):
         source machine.
 
         """
-        context = context.elevated()
-        migration_ref = self.db.migration_get(context, migration_id)
+        migration_ref = self.db.migration_get(context.elevated(),
+                migration_id)
 
         # NOTE(comstud): A revert_resize is essentially a resize back to
         # the old size, so we need to send a usage event here.
@@ -1520,7 +1521,8 @@ class ComputeManager(manager.SchedulerDependentManager):
         in the database.
 
         """
-        migration_ref = self.db.migration_get(context, migration_id)
+        elevated = context.elevated()
+        migration_ref = self.db.migration_get(elevated, migration_id)
 
         with self._error_out_instance_on_exception(context, instance['uuid'],
                                                    reservations):
@@ -1572,7 +1574,7 @@ class ComputeManager(manager.SchedulerDependentManager):
                                   expected_task_state=task_states.
                                       RESIZE_REVERTING)
 
-            self.db.migration_update(context, migration_id,
+            self.db.migration_update(elevated, migration_id,
                     {'status': 'reverted'})
 
             self._notify_about_instance_usage(
@@ -1600,7 +1602,6 @@ class ComputeManager(manager.SchedulerDependentManager):
         Possibly changes the RAM and disk size in the process.
 
         """
-        context = context.elevated()
         with self._error_out_instance_on_exception(context, instance['uuid'],
                                                    reservations):
             compute_utils.notify_usage_exists(
@@ -1620,7 +1621,7 @@ class ComputeManager(manager.SchedulerDependentManager):
             old_instance_type = instance_types.get_instance_type(
                     old_instance_type_id)
 
-            migration_ref = self.db.migration_create(context,
+            migration_ref = self.db.migration_create(context.elevated(),
                     {'instance_uuid': instance['uuid'],
                      'source_compute': instance['host'],
                      'dest_compute': self.host,
@@ -1647,9 +1648,9 @@ class ComputeManager(manager.SchedulerDependentManager):
     def resize_instance(self, context, instance, image,
                         reservations=None, migration=None, migration_id=None):
         """Starts the migration of a running instance to another host."""
-        context = context.elevated()
+        elevated = context.elevated()
         if not migration:
-            migration = self.db.migration_get(context, migration_id)
+            migration = self.db.migration_get(elevated, migration_id)
         with self._error_out_instance_on_exception(context, instance['uuid'],
                                                    reservations):
             instance_type_ref = self.db.instance_type_get(context,
@@ -1657,7 +1658,7 @@ class ComputeManager(manager.SchedulerDependentManager):
 
             network_info = self._get_instance_nw_info(context, instance)
 
-            self.db.migration_update(context,
+            self.db.migration_update(elevated,
                                      migration['id'],
                                      {'status': 'migrating'})
 
@@ -1689,7 +1690,7 @@ class ComputeManager(manager.SchedulerDependentManager):
                 self.network_api.migrate_instance_start(context, instance,
                                                            self.host)
 
-            migration = self.db.migration_update(context,
+            migration = self.db.migration_update(elevated,
                                                  migration['id'],
                                                  {'status': 'post-migrating'})
 
@@ -1767,7 +1768,7 @@ class ComputeManager(manager.SchedulerDependentManager):
                                          expected_task_state=task_states.
                                              RESIZE_FINISH)
 
-        self.db.migration_update(context, migration['id'],
+        self.db.migration_update(context.elevated(), migration['id'],
                                  {'status': 'finished'})
 
         self._notify_about_instance_usage(
@@ -1786,7 +1787,8 @@ class ComputeManager(manager.SchedulerDependentManager):
 
         """
         if not migration:
-            migration = self.db.migration_get(context, migration_id)
+            migration = self.db.migration_get(context.elevated(),
+                    migration_id)
         try:
             self._finish_resize(context, instance, migration,
                                 disk_info, image)