vtruncbuf
vtruncbuf(DETOV(dep), lastblock + 1, 0, 0);
error = vtruncbuf(vp, cred, nsize, biosize);
int vtruncbuf(struct vnode *, daddr_t, bool, int);
error = vtruncbuf(ovp, lastblock + 1, 0, 0);
error = vtruncbuf(ovp, lastblock + 1, 0, 0);