vn_lock_pair
vn_lock_pair(invp, false, LK_SHARED, outvp, false, LK_EXCLUSIVE);
vn_lock_pair(vp, false, LK_EXCLUSIVE, uvp, true, LK_EXCLUSIVE);
vn_lock_pair(unionvp1, !vp1_doomed, lkflags1,
vn_lock_pair(dvp, dvp_locked, LK_EXCLUSIVE, vp, false, LK_EXCLUSIVE);
vn_lock_pair(vp, false, LK_EXCLUSIVE, uvp, true, LK_EXCLUSIVE);
vn_lock_pair(vp, false, LK_EXCLUSIVE, uvp, true, LK_EXCLUSIVE);
vn_lock_pair(uvp, true, LK_EXCLUSIVE, lvp, false, LK_EXCLUSIVE);
vn_lock_pair(vp, false, LK_EXCLUSIVE, newdp, false, LK_EXCLUSIVE);
void vn_lock_pair(struct vnode *vp1, bool vp1_locked, int lkflags1,
vn_lock_pair(dvp, false, LK_EXCLUSIVE, vp, true, LK_EXCLUSIVE);
vn_lock_pair(dvp, false, LK_EXCLUSIVE, vp, true,
vn_lock_pair(dvp, true, LK_EXCLUSIVE, vp, false,
vn_lock_pair(dvp, false, LK_EXCLUSIVE, vp, false, LK_EXCLUSIVE);
vn_lock_pair(vp, false, LK_EXCLUSIVE, vp1, false, LK_EXCLUSIVE);