A review comment for WL#4441 " LOCK_open: Remove requirement of

mutex protecting thd->open_tables".

We should not manipulate with table->s->version outside the 
table definition cache code, but use the TDC API
to achieve the desired result.

Fix one violation: close_all_tables_for_name().

sql/sql_base.cc

@@ -1022,6 +1022,9 @@ bool close_cached_tables(THD *thd, TABLE_LIST *tables, bool have_lock,
     TABLE_LIST *tables_to_reopen= (tables ? tables :
                                   thd->locked_tables_list.locked_tables());
 
+    /* Close open HANLER instances to avoid self-deadlock. */
+    mysql_ha_flush_tables(thd, tables_to_reopen);
+
     for (TABLE_LIST *table_list= tables_to_reopen; table_list;
          table_list= table_list->next_global)
     {
@@ -1049,7 +1052,8 @@ bool close_cached_tables(THD *thd, TABLE_LIST *tables, bool have_lock,
   {
     found= FALSE;
     /*
-      To avoid self and other kinds of deadlock we have to flush open HANDLERs.
+      To a self-deadlock or deadlocks with other FLUSH threads
+      waiting on our open HANDLERs, we have to flush them.
     */
     mysql_ha_flush(thd);
     DEBUG_SYNC(thd, "after_flush_unlock");
@@ -1308,8 +1312,7 @@ static void close_open_tables(THD *thd)
 
 
 /**
-  Close all open instances of the table but keep the MDL lock,
+  Close all open instances of the table but keep the MDL lock.
-  if any.
 
   Works both under LOCK TABLES and in the normal mode.
   Removes all closed instances of the table from the table cache.
@@ -1323,6 +1326,8 @@ static void close_open_tables(THD *thd)
                      In that case the documented behaviour is to
                      implicitly remove the table from LOCK TABLES
                      list.
+
+  @pre Must be called with an X MDL lock on the table.
 */
 
 void
@@ -1331,6 +1336,8 @@ close_all_tables_for_name(THD *thd, TABLE_SHARE *share,
 {
   char key[MAX_DBKEY_LENGTH];
   uint key_length= share->table_cache_key.length;
+  const char *db= key;
+  const char *table_name= db + share->db.length + 1;
 
   memcpy(key, share->table_cache_key.str, key_length);
 
@@ -1352,8 +1359,6 @@ close_all_tables_for_name(THD *thd, TABLE_SHARE *share,
       */
       mysql_lock_remove(thd, thd->lock, table);
 
-      /* Make sure the table is removed from the cache */
-      table->s->version= 0;
       /* Inform handler that table will be dropped after close */
       if (table->db_stat) /* Not true for partitioned tables. */
         table->file->extra(HA_EXTRA_PREPARE_FOR_DROP);
@@ -1365,7 +1370,14 @@ close_all_tables_for_name(THD *thd, TABLE_SHARE *share,
       prev= &table->next;
     }
   }
-  /* We have been removing tables from the table cache. */
+  /* Remove the table share from the cache. */
+  mysql_mutex_lock(&LOCK_open);
+  tdc_remove_table(thd, TDC_RT_REMOVE_ALL, db, table_name);
+  mysql_mutex_unlock(&LOCK_open);
+  /*
+    There could be a FLUSH thread waiting
+    on the table to go away. Wake it up.
+  */
   broadcast_refresh();
 }
 

sql/sql_handler.cc

@@ -833,6 +833,35 @@ void mysql_ha_rm_tables(THD *thd, TABLE_LIST *tables)
 }
 
 
+/**
+  Close cursors of matching tables from the HANDLER's hash table.
+
+  @param thd Thread identifier.
+  @param tables The list of tables to flush.
+*/
+
+void mysql_ha_flush_tables(THD *thd, TABLE_LIST *all_tables)
+{
+  DBUG_ENTER("mysql_ha_flush_tables");
+
+  for (TABLE_LIST *table_list= all_tables; table_list;
+       table_list= table_list->next_global)
+  {
+    TABLE_LIST *hash_tables= mysql_ha_find(thd, table_list);
+    /* Close all aliases of the same table. */
+    while (hash_tables)
+    {
+      TABLE_LIST *next_local= hash_tables->next_local;
+      if (hash_tables->table)
+        mysql_ha_close_table(thd, hash_tables);
+      hash_tables= next_local;
+    }
+  }
+
+  DBUG_VOID_RETURN;
+}
+
+
 /**
   Flush (close and mark for re-open) all tables that should be should
   be reopen.

sql/sql_handler.h

@@ -28,6 +28,7 @@ bool mysql_ha_close(THD *thd, TABLE_LIST *tables);
 bool mysql_ha_read(THD *, TABLE_LIST *,enum enum_ha_read_modes,char *,
                    List<Item> *,enum ha_rkey_function,Item *,ha_rows,ha_rows);
 void mysql_ha_flush(THD *thd);
+void mysql_ha_flush_tables(THD *thd, TABLE_LIST *all_tables);
 void mysql_ha_rm_tables(THD *thd, TABLE_LIST *tables);
 void mysql_ha_cleanup(THD *thd);
 void mysql_ha_move_tickets_after_trans_sentinel(THD *thd);