GB_NOWITNESS
lockflags |= (flags & GB_NOWITNESS) != 0 ? LK_NOWITNESS : 0;
gbflags |= IS_SNAPSHOT(ip) ? GB_NOWITNESS : 0;
gbwflag = IS_SNAPSHOT(ip) ? GB_NOWITNESS : 0;
bflag |= IS_SNAPSHOT(ip) ? GB_NOWITNESS : 0;