+ /*
+ * We need to flush the buffer workqueue to ensure that all IO
+ * completion processing is 100% done. Just waiting on buffer locks is
+ * not sufficient for async IO as the reference count held over IO is
+ * not released until after the buffer lock is dropped. Hence we need to
+ * ensure here that all reference counts have been dropped before we
+ * start walking the LRU list.
+ */
+ flush_workqueue(btp->bt_mount->m_buf_workqueue);
+