Fix bug #57700 Latching order violation in row_truncate_table_for_mysql().

Approved by Sunny Bains

storage/innodb_plugin/ChangeLog

+2010-10-24	The InnoDB Team
+
+	* row/row0mysql.c
+	Fix Bug #57700 Latching order violation in
+	row_truncate_table_for_mysql()
+
 2010-10-20	The InnoDB Team
 
 	* dict/dict0load.c

storage/innodb_plugin/row/row0mysql.c

@@ -2782,15 +2782,6 @@ row_truncate_table_for_mysql(
 
 	trx->table_id = table->id;
 
-	/* Lock all index trees for this table, as we will
-	truncate the table/index and possibly change their metadata.
-	All DML/DDL are blocked by table level lock, with
-	a few exceptions such as queries into information schema
-	about the table, MySQL could try to access index stats
-	for this kind of query, we need to use index locks to
-	sync up */
-	dict_table_x_lock_indexes(table);
-
 	if (table->space && !table->dir_path_of_temp_table) {
 		/* Discard and create the single-table tablespace. */
 		ulint	space	= table->space;
@@ -2803,6 +2794,11 @@ row_truncate_table_for_mysql(
 
 			dict_hdr_get_new_id(NULL, NULL, &space);
 
+			/* Lock all index trees for this table. We must
+			do so after dict_hdr_get_new_id() to preserve
+			the latch order */
+			dict_table_x_lock_indexes(table);
+
 			if (space == ULINT_UNDEFINED
 			    || fil_create_new_single_table_tablespace(
 				    space, table->name, FALSE, flags,
@@ -2836,6 +2832,15 @@ row_truncate_table_for_mysql(
 					FIL_IBD_FILE_INITIAL_SIZE, &mtr);
 			mtr_commit(&mtr);
 		}
+	} else {
+		/* Lock all index trees for this table, as we will
+		truncate the table/index and possibly change their metadata.
+		All DML/DDL are blocked by table level lock, with
+		a few exceptions such as queries into information schema
+		about the table, MySQL could try to access index stats
+		for this kind of query, we need to use index locks to
+		sync up */
+		dict_table_x_lock_indexes(table);
 	}
 
 	/* scan SYS_INDEXES for all indexes of the table */