diff --git a/nova/compute/api.py b/nova/compute/api.py
index 82d7409..6d3a0b2 100644
--- a/nova/compute/api.py
+++ b/nova/compute/api.py
@@ -507,6 +507,12 @@ class API(base.Base):
                         security_group, block_device_mapping)
                 instances.append(instance)
                 instance_uuids.append(instance['uuid'])
+                self._validate_bdm(context, instance)
+                # send a state update notification for the initial create to
+                # show it going from non-existent to BUILDING
+                notifications.send_update_with_states(context, instance, None,
+                        vm_states.BUILDING, None, None, service="api")
+
 
         # In the case of any exceptions, attempt DB cleanup and rollback the
         # quota reservations.
@@ -623,6 +629,21 @@ class API(base.Base):
             self.db.block_device_mapping_update_or_create(elevated_context,
                                                           values)
 
+    def _validate_bdm(self, context, instance):
+        for bdm in self.db.block_device_mapping_get_all_by_instance(
+                context, instance['uuid']):
+            # NOTE(vish): For now, just make sure the volumes are accessible.
+            if bdm['snapshot_id'] is not None and bdm['volume_id'] is None:
+                try:
+                    self.volume_api.get_snapshot(context, bdm['snapshot_id'])
+                except Exception:
+                    raise exception.InvalidBDMSnapshot(id=bdm['snapshot_id'])
+            elif bdm['volume_id'] is not None:
+                try:
+                    self.volume_api.get(context, bdm['volume_id'])
+                except Exception:
+                    raise exception.InvalidBDMVolume(id=bdm['volume_id'])
+
     def _populate_instance_for_bdm(self, context, instance, instance_type,
             image, block_device_mapping):
         """Populate instance block device mapping information."""
@@ -735,11 +756,6 @@ class API(base.Base):
         self._populate_instance_for_bdm(context, instance,
                 instance_type, image, block_device_mapping)
 
-        # send a state update notification for the initial create to
-        # show it going from non-existent to BUILDING
-        notifications.send_update_with_states(context, instance, None,
-                vm_states.BUILDING, None, None, service="api")
-
         return instance
 
     def _check_create_policies(self, context, availability_zone,
diff --git a/nova/exception.py b/nova/exception.py
index 8de360d..2f58322 100644
--- a/nova/exception.py
+++ b/nova/exception.py
@@ -219,6 +219,20 @@ class Invalid(NovaException):
     code = 400
 
 
+class InvalidBDM(Invalid):
+    message = _("Block Device Mapping is Invalid.")
+
+
+class InvalidBDMSnapshot(InvalidBDM):
+    message = _("Block Device Mapping is Invalid: "
+                "failed to get snapshot %(id)s.")
+
+
+class InvalidBDMVolume(InvalidBDM):
+    message = _("Block Device Mapping is Invalid: "
+                "failed to get volume %(id)s.")
+
+
 class InvalidSnapshot(Invalid):
     message = _("Invalid snapshot") + ": %(reason)s"