ovl_workdir_cleanup
int ovl_workdir_cleanup(struct ovl_fs *ofs, struct dentry *parent,
err = ovl_workdir_cleanup(ofs, path->dentry, path->mnt,
err = ovl_workdir_cleanup(ofs, indexdir, path.mnt, index, 1);
err = ovl_workdir_cleanup(ofs, ofs->workbasedir, mnt, work, 0);