LK_NOWITNESS
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY | LK_NOWITNESS);
lockmgr(nvp->v_vnlock, LK_EXCLUSIVE | LK_NOWITNESS, NULL);
lockmgr(vp->v_vnlock, LK_EXCLUSIVE | LK_NOWITNESS, NULL);
lockmgr(vp->v_vnlock, LK_EXCLUSIVE | LK_NOWITNESS, NULL);
(((x) & LK_NOWITNESS) == 0 && !LK_TRYOP(x))
if ((flags & LK_NOWITNESS) == 0)
error = BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWITNESS, NULL);
lockflags |= (flags & GB_NOWITNESS) != 0 ? LK_NOWITNESS : 0;
lockmgr(vp->v_vnlock, LK_EXCLUSIVE | LK_NOWITNESS, NULL);
wflag = IS_SNAPSHOT(ip) ? LK_NOWITNESS : 0;
BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWITNESS, NULL);