diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index 3243cdf97f33..cbddb917d6ff 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1520,6 +1520,16 @@ xfs_wait_buftarg(
 	LIST_HEAD(dispose);
 	int loop = 0;
 
+	/*
+	 * 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.
+	 */
+	drain_workqueue(btp->bt_mount->m_buf_workqueue);
+
 	/* loop until there is nothing left on the lru list. */
 	while (list_lru_count(&btp->bt_lru)) {
 		list_lru_walk(&btp->bt_lru, xfs_buftarg_wait_rele,