> I also see examples of files that get unlinked from the upper layer but
> never get properly released.  I cannot generate this on demand, however.
> The symptom is a filesystem which passes fsck clean tests, yet has
> unreferenced allocated inodes--if you run fsck by hand, lots of stuff
> ends up in lost+found.

I got this too.  I started noticing the damage when certain empty
directories (ls -W could see no files) would not rmdir because they
"weren't empty."