Unable to create table with data directory

This is right out of the MySQL documentation:

• MariaDB [pets]> CREATE TABLE t1 (c1 INT PRIMARY KEY) DATA DIRECTORY = '/home/dch/ms';
• ERROR 1005 (HY000): Can't create table `pets`.`t1` (errno: 168 "Unknown (generic) error from engine")

The external directory is owned my mysql.

I am working on a project and I really need this to work. In the interim, my project is halted.