Remember original table row pack type for ALTER TABLE if table is not copied.

sql/sql_table.cc

@@ -4124,7 +4124,8 @@ bool mysql_create_table_no_lock(THD *thd,
   set_table_default_charset(thd, create_info, (char*) db);
 
   db_options= create_info->table_options;
-  if (create_info->row_type != ROW_TYPE_FIXED &&
+  if (!create_info->frm_only &&
+      create_info->row_type != ROW_TYPE_FIXED &&
       create_info->row_type != ROW_TYPE_DEFAULT)
     db_options|= HA_OPTION_PACK_RECORD;
   alias= table_case_name(create_info, table_name);
@@ -6670,9 +6671,19 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
                   my_sleep(100000););
   /*
     Create a table with a temporary name.
-    With create_info->frm_only == 1 this creates a .frm file only.
+    With create_info->frm_only == 1 this creates a .frm file only and
+    we keep the original row format.
     We don't log the statement, it will be logged later.
   */
+  if (need_copy_table == ALTER_TABLE_METADATA_ONLY)
+  {
+    DBUG_ASSERT(create_info->frm_only);
+    /* Ensure we keep the original table format */
+    create_info->table_options= ((create_info->table_options &
+                                  ~HA_OPTION_PACK_RECORD) |
+                                 (table->s->db_create_options &
+                                  HA_OPTION_PACK_RECORD));
+  }
   tmp_disable_binlog(thd);
   error= mysql_create_table_no_lock(thd, new_db, tmp_name,
                                     create_info,