Merge fix for BUG39053 to 5.1-bugteam.

include/mysql/plugin.h

@@ -801,30 +801,37 @@ void mysql_query_cache_invalidate4(MYSQL_THD thd,
                                    const char *key, unsigned int key_length,
                                    int using_trx);
 
-#ifdef __cplusplus
-}
-#endif
 
-#ifdef __cplusplus
 /**
   Provide a handler data getter to simplify coding
 */
-inline
-void *
-thd_get_ha_data(const MYSQL_THD thd, const struct handlerton *hton)
-{
-  return *thd_ha_data(thd, hton);
-}
+void *thd_get_ha_data(const MYSQL_THD thd, const struct handlerton *hton);
+
 
 /**
   Provide a handler data setter to simplify coding
+
+  @details
+  Set ha_data pointer (storage engine per-connection information).
+
+  To avoid unclean deactivation (uninstall) of storage engine plugin
+  in the middle of transaction, additional storage engine plugin
+  lock is acquired.
+
+  If ha_data is not null and storage engine plugin was not locked
+  by thd_set_ha_data() in this connection before, storage engine
+  plugin gets locked.
+
+  If ha_data is null and storage engine plugin was locked by
+  thd_set_ha_data() in this connection before, storage engine
+  plugin lock gets released.
+
+  If handlerton::close_connection() didn't reset ha_data, server does
+  it immediately after calling handlerton::close_connection().
 */
-inline
-void
-thd_set_ha_data(const MYSQL_THD thd, const struct handlerton *hton,
-                const void *ha_data)
-{
-  *thd_ha_data(thd, hton)= (void*) ha_data;
+void thd_set_ha_data(MYSQL_THD thd, const struct handlerton *hton,
+                     const void *ha_data);
+#ifdef __cplusplus
 }
 #endif
 

include/mysql/plugin.h.pp

@@ -137,3 +137,6 @@ void thd_get_xid(const void* thd, MYSQL_XID *xid);
 void mysql_query_cache_invalidate4(void* thd,
                                    const char *key, unsigned int key_length,
                                    int using_trx);
+void *thd_get_ha_data(const void* thd, const struct handlerton *hton);
+void thd_set_ha_data(void* thd, const struct handlerton *hton,
+                     const void *ha_data);

sql/handler.cc

@@ -159,7 +159,7 @@ redo:
 }
 
 
-plugin_ref ha_lock_engine(THD *thd, handlerton *hton)
+plugin_ref ha_lock_engine(THD *thd, const handlerton *hton)
 {
   if (hton)
   {
@@ -601,9 +601,13 @@ static my_bool closecon_handlerton(THD *thd, plugin_ref plugin,
     there's no need to rollback here as all transactions must
     be rolled back already
   */
-  if (hton->state == SHOW_OPTION_YES && hton->close_connection &&
-      thd_get_ha_data(thd, hton))
-    hton->close_connection(hton, thd);
+  if (hton->state == SHOW_OPTION_YES && thd_get_ha_data(thd, hton))
+  {
+    if (hton->close_connection)
+      hton->close_connection(hton, thd);
+    /* make sure ha_data is reset and ha_data_lock is released */
+    thd_set_ha_data(thd, hton, NULL);
+  }
   return FALSE;
 }
 

sql/handler.h

@@ -1956,7 +1956,7 @@ extern ulong total_ha, total_ha_2pc;
 /* lookups */
 handlerton *ha_default_handlerton(THD *thd);
 plugin_ref ha_resolve_by_name(THD *thd, const LEX_STRING *name);
-plugin_ref ha_lock_engine(THD *thd, handlerton *hton);
+plugin_ref ha_lock_engine(THD *thd, const handlerton *hton);
 handlerton *ha_resolve_by_legacy_type(THD *thd, enum legacy_db_type db_type);
 handler *get_new_handler(TABLE_SHARE *share, MEM_ROOT *alloc,
                          handlerton *db_type);

sql/sql_class.cc

@@ -284,6 +284,37 @@ void **thd_ha_data(const THD *thd, const struct handlerton *hton)
   return (void **) &thd->ha_data[hton->slot].ha_ptr;
 }
 
+
+/**
+  Provide a handler data getter to simplify coding
+*/
+extern "C"
+void *thd_get_ha_data(const THD *thd, const struct handlerton *hton)
+{
+  return *thd_ha_data(thd, hton);
+}
+
+
+/**
+  Provide a handler data setter to simplify coding
+  @see thd_set_ha_data() definition in plugin.h
+*/
+extern "C"
+void thd_set_ha_data(THD *thd, const struct handlerton *hton,
+                     const void *ha_data)
+{
+  plugin_ref *lock= &thd->ha_data[hton->slot].lock;
+  if (ha_data && !*lock)
+    *lock= ha_lock_engine(NULL, (handlerton*) hton);
+  else if (!ha_data && *lock)
+  {
+    plugin_unlock(NULL, *lock);
+    *lock= NULL;
+  }
+  *thd_ha_data(thd, hton)= (void*) ha_data;
+}
+
+
 extern "C"
 long long thd_test_options(const THD *thd, long long test_options)
 {

sql/sql_class.h

@@ -1264,7 +1264,11 @@ struct Ha_data
     @sa trans_register_ha()
   */
   Ha_trx_info ha_info[2];
-
+  /**
+    NULL: engine is not bound to this thread
+    non-NULL: engine is bound to this thread, engine shutdown forbidden
+  */
+  plugin_ref lock;
   Ha_data() :ha_ptr(NULL) {}
 };