ovl_dir_modified
ovl_dir_modified(old->d_parent, ovl_type_origin(old) ||
ovl_dir_modified(new->d_parent, ovl_type_origin(old) ||
ovl_dir_modified(dentry->d_parent, false);
ovl_dir_modified(dentry->d_parent, false);
ovl_dir_modified(dentry->d_parent, true);
ovl_dir_modified(dentry->d_parent, ovl_type_origin(dentry));
void ovl_dir_modified(struct dentry *dentry, bool impurity);