[$] Messiness in removing directories

In the filesystem track at the 2018 Linux Storage, Filesystem, andMemory-Management Summit (LSFMM), Al Viro discussed some problems he hasrecently spotted in the implementation of rmdir().He covered some of the history of that implementation and how things got towhere they are now. He also described areas that needed to be checkedbecause the problem may be present in different places in multiple filesystems.