For whatever reason, the directory shows up with Nlink == 2 there.

This is necessary on Linux to make MemFSTest.Mkdir_PermissionDenied
pass, for the reasons outlined in commit e31cb17e. I don't quite
understand why it doesn't come up on OS X.

Linux apparently doesn't like setting atime to time.Time{}.

Its presence was confusing because it is never anything but the real
clock.