A suggestion for avoiding potential races with is_paused

Dear developers, in below code, should the lock paused in do_resume be released after is_paused=false? In do_pause, is_paused=true is guarded by the lock but not in do_resume.

https://github.com/libguestfs/nbdkit/blob/master/filters/pause/pause.c#L146-L174

static void
do_pause (void)
{
  ...;
  pthread_mutex_lock (&paused);
  is_paused = true;

  ...;
  while (count_requests > 0)
    pthread_cond_wait (&count_cond, &count_lock);
  nbdkit_debug ("pause: paused");
}

static void
do_resume (void)
{
  if (!is_paused) return;

  /* Release the worker threads. */
  pthread_mutex_unlock (&paused);
  is_paused = false;
  nbdkit_debug ("pause: resumed");
}