cache_fromdvp
cache_fromdvp(pvp, cred, makeit + 1, nch);
int cache_fromdvp(struct vnode *, struct ucred *, int, struct nchandle *);
if ((error = cache_fromdvp(dp, cred, 1, &nch)) != 0)
cache_fromdvp(vp, NULL, 0, &dnch);