diff --git a/storage/innobase/dict/dict0dict.c b/storage/innobase/dict/dict0dict.c
index d3b277d2d7a..d2b59469cdc 100644
--- a/storage/innobase/dict/dict0dict.c
+++ b/storage/innobase/dict/dict0dict.c
@@ -618,13 +618,11 @@ dict_table_get_on_id(
 
 	if (ut_dulint_cmp(table_id, DICT_FIELDS_ID) <= 0
 	    || trx->dict_operation_lock_mode == RW_X_LATCH) {
-		/* It is a system table which will always exist in the table
-		cache: we avoid acquiring the dictionary mutex, because
-		if we are doing a rollback to handle an error in TABLE
-		CREATE, for example, we already have the mutex! */
 
-		ut_ad(mutex_own(&(dict_sys->mutex))
-		      || trx->dict_operation_lock_mode == RW_X_LATCH);
+		/* Note: An X latch implies that the transaction
+		already owns the dictionary mutex. */
+
+		ut_ad(mutex_own(&dict_sys->mutex));
 
 		return(dict_table_get_on_id_low(table_id));
 	}
diff --git a/storage/innobase/include/sync0sync.h b/storage/innobase/include/sync0sync.h
index 6a61330f97e..9430d4cb723 100644
--- a/storage/innobase/include/sync0sync.h
+++ b/storage/innobase/include/sync0sync.h
@@ -401,7 +401,7 @@ or row lock! */
 					locked; see e.g.
 					ibuf_bitmap_get_map_page(). */
 #define	SYNC_DICT_OPERATION	1001	/* table create, drop, etc. reserve
-					this in X-mode, implicit or backround
+					this in X-mode; implicit or backround
 					operations purge, rollback, foreign
 					key checks reserve this in S-mode */
 #define SYNC_DICT		1000
diff --git a/storage/innobase/row/row0undo.c b/storage/innobase/row/row0undo.c
index f03f84ed1b0..7f31fd0060c 100644
--- a/storage/innobase/row/row0undo.c
+++ b/storage/innobase/row/row0undo.c
@@ -272,7 +272,7 @@ row_undo(
 
 	if (locked_data_dict) {
 
-		row_mysql_lock_data_dictionary(trx);
+		row_mysql_freeze_data_dictionary(trx);
 	}
 
 	if (node->state == UNDO_NODE_INSERT) {
@@ -287,7 +287,7 @@ row_undo(
 
 	if (locked_data_dict) {
 
-		row_mysql_unlock_data_dictionary(trx);
+		row_mysql_unfreeze_data_dictionary(trx);
 	}
 
 	/* Do some cleanup */
diff --git a/storage/innodb_plugin/dict/dict0dict.c b/storage/innodb_plugin/dict/dict0dict.c
index 8be5b7acac5..fe4e058e122 100644
--- a/storage/innodb_plugin/dict/dict0dict.c
+++ b/storage/innodb_plugin/dict/dict0dict.c
@@ -570,13 +570,11 @@ dict_table_get_on_id(
 
 	if (ut_dulint_cmp(table_id, DICT_FIELDS_ID) <= 0
 	    || trx->dict_operation_lock_mode == RW_X_LATCH) {
-		/* It is a system table which will always exist in the table
-		cache: we avoid acquiring the dictionary mutex, because
-		if we are doing a rollback to handle an error in TABLE
-		CREATE, for example, we already have the mutex! */
 
-		ut_ad(mutex_own(&(dict_sys->mutex))
-		      || trx->dict_operation_lock_mode == RW_X_LATCH);
+		/* Note: An X latch implies that the transaction
+		already owns the dictionary mutex. */
+
+		ut_ad(mutex_own(&dict_sys->mutex));
 
 		return(dict_table_get_on_id_low(table_id));
 	}
diff --git a/storage/innodb_plugin/include/sync0sync.h b/storage/innodb_plugin/include/sync0sync.h
index d470b823fc3..71c9920a10b 100644
--- a/storage/innodb_plugin/include/sync0sync.h
+++ b/storage/innodb_plugin/include/sync0sync.h
@@ -438,7 +438,7 @@ or row lock! */
 #define SYNC_FILE_FORMAT_TAG	1200	/* Used to serialize access to the
 					file format tag */
 #define	SYNC_DICT_OPERATION	1001	/* table create, drop, etc. reserve
-					this in X-mode, implicit or backround
+					this in X-mode; implicit or backround
 					operations purge, rollback, foreign
 					key checks reserve this in S-mode */
 #define SYNC_DICT		1000
diff --git a/storage/innodb_plugin/row/row0undo.c b/storage/innodb_plugin/row/row0undo.c
index 3d739c9689a..9ef842b5114 100644
--- a/storage/innodb_plugin/row/row0undo.c
+++ b/storage/innodb_plugin/row/row0undo.c
@@ -297,7 +297,7 @@ row_undo(
 
 	if (locked_data_dict) {
 
-		row_mysql_lock_data_dictionary(trx);
+		row_mysql_freeze_data_dictionary(trx);
 	}
 
 	if (node->state == UNDO_NODE_INSERT) {
@@ -312,7 +312,7 @@ row_undo(
 
 	if (locked_data_dict) {
 
-		row_mysql_unlock_data_dictionary(trx);
+		row_mysql_unfreeze_data_dictionary(trx);
 	}
 
 	/* Do some cleanup */