v_specbitmap
clrbit(pvp->v_specbitmap, minor(dev) >> CLONE_SHIFT);
if (isclr(vp->v_specbitmap, i)) {
setbit(vp->v_specbitmap, i);
clrbit(vp->v_specbitmap, i);
clrbit(vp->v_specbitmap, i);
free(vp->v_specbitmap, M_VNODE, CLONE_MAPSZ);
nvp->v_specbitmap = NULL;
nvp->v_specbitmap = vp->v_specbitmap;
nvp->v_specbitmap = malloc(CLONE_MAPSZ,