GIF_GLOP_PENDING
set_bit(GIF_GLOP_PENDING, &ip->i_flags);
clear_bit_unlock(GIF_GLOP_PENDING, &ip->i_flags);
wake_up_bit(&ip->i_flags, GIF_GLOP_PENDING);
wait_on_bit_io(&ip->i_flags, GIF_GLOP_PENDING, TASK_UNINTERRUPTIBLE);