ref_tracker_dir_symlink
void ref_tracker_dir_symlink(struct ref_tracker_dir *dir, const char *fmt, ...);
EXPORT_SYMBOL(ref_tracker_dir_symlink);
ref_tracker_dir_symlink(&net->refcnt_tracker, "netns-%llx-%u-refcnt",
ref_tracker_dir_symlink(&net->notrefcnt_tracker, "netns-%llx-%u-notrefcnt",