UF_SETTABLE
ptyfs->ptyfs_flags |= (vap->va_flags & UF_SETTABLE);
node->tn_flags |= (flags & UF_SETTABLE);
(flags & UF_SETTABLE) != flags) {
ip->flags |= (flags & UF_SETTABLE);
ip->i_flags |= (vap->va_flags & UF_SETTABLE);
ip->i_flags |= (vap->va_flags & UF_SETTABLE);
& UF_SETTABLE) /* user settable flags */