mbuf_setlen
mbuf_setlen(mb, 0);
mbuf_setlen(mp, 0);
mbuf_setlen(mp, mbuf_len(mp) + xfer);
mbuf_setlen(mp, 0);
mbuf_setlen(mp, mbuf_len(mp) + rem);
mbuf_setlen(nd->nd_md, mbuf_len(nd->nd_md) - left);
mbuf_setlen(mp2, mbuf_len(mp2) - xfer);
mbuf_setlen(nd->nd_md, siz);
mbuf_setlen(mreq, 0);
mbuf_setlen(m1, 0);
mbuf_setlen(m2, mbuf_len(m2) + xfer);
mbuf_setlen(m2, mbuf_len(m2) + rem);
mbuf_setlen(m, mbuf_len(m) - offs);
mbuf_setlen(mb, bpos - NFSMTOD(mb, caddr_t));
mbuf_setlen(mb2, 0);
mbuf_setlen(m, 0);
mbuf_setlen(m, mbuf_len(m) - len);
mbuf_setlen(m, count);
mbuf_setlen(m, 0);