fo_stat
errno = (f->f_ops->fo_stat)(f, sb);
int (*fo_stat)(struct open_file *, struct stat *);
.fo_stat = dmabuf_stat,
.fo_stat = fbadop_stat,
error = fo_stat(fp, ub, td->td_ucred);
.fo_stat = badfo_stat,
.fo_stat = kqueue_stat,
error = fo_stat(fp, ub, fp->f_cred);
.fo_stat = mq_stat_fop,
.fo_stat = pipe_stat,
.fo_stat = soo_stat,
.fo_stat = vn_statfile,
int (*fo_stat) (struct file *fp, struct stat *sb,
error = (*fp->f_ops->fo_stat)(fp, sb, cred);
.fo_stat = devfs_fo_stat,