Index: modules/block/block.install
===================================================================
RCS file: /cvs/drupal/drupal/modules/block/block.install,v
retrieving revision 1.39
diff -u -p -r1.39 block.install
--- modules/block/block.install	4 Mar 2010 21:42:00 -0000	1.39
+++ modules/block/block.install	11 Mar 2010 08:42:28 -0000
@@ -217,6 +217,32 @@ function block_install() {
 }
 
 /**
+ * @defgroup updates-6.x-extra Extra block updates for 6.x
+ * @{
+ */
+
+/**
+ * Cleanup orphan block's data.
+ */
+function block_update_6000() {
+  // Cleanup for deleted custom blocks.
+  db_query("DELETE FROM {blocks_roles} WHERE module = 'block' AND delta NOT IN (SELECT b.bid FROM {boxes} b)")->execute();
+  // Cleanup for uninstalled modules' blocks.
+  db_query("DELETE FROM {blocks} WHERE module IN (SELECT s.name FROM {system} s WHERE s.type = 'module' AND s.status = 0 AND s.schema_version = -1)")->execute();
+  db_query("DELETE FROM {blocks_roles} WHERE module IN (SELECT s.name FROM {system} s WHERE s.type = 'module' AND s.status = 0 AND s.schema_version = -1)")->execute();
+}
+
+/**
+ * @} End of "defgroup updates-6.x-extra"
+ * The next series of updates should start at 7000.
+ */
+
+/**
+ * @defgroup updates-6.x-to-7.x System updates from 6.x to 7.x
+ * @{
+ */
+
+/**
  * Set system.weight to a low value for block module.
  *
  * Block should go first so that other modules can alter its output
@@ -451,3 +477,8 @@ function block_update_7004() {
   // Rebuild theme data, so the new 'help' region is identified.
   system_rebuild_theme_data();
 }
+
+/**
+ * @} End of "defgroup updates-6.x-to-7.x"
+ * The next series of updates should start at 8000.
+ */