Code review comment for lp:~stewart/percona-server/5.5.27-plus-bugfixes

I don't the "It may be impossible case" code in the original fix. The upstream code is:

---
  } else {

   block_mutex = buf_page_get_mutex(bpage);
   mutex_enter(block_mutex);

   if (bpage->buf_fix_count > 0) {

    mutex_exit(block_mutex);

    /* We cannot remove this page during
    this scan yet; maybe the system is
    currently reading it in, or flushing
    the modifications to the file */

    all_freed = FALSE;

    goto next_page;
   }
  }

---

Which appears to be rather different than what is now in Percona Server. Why?