sanity/test_205d is the test case for LU-16110. It may fail silently for 2 reasons:

1. yaml.safe_load_all() does not report error unless its content is used again (e.g. print the content)
2. use "output=$()" to capture the output of a command. But it converts newline to space, so that valid YAML is converted to invalid. But the error cannot be found due to the reason above

And in a multi-mds system, put the testdir on mds1 forcefully