From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 440E6C54FCC for ; Mon, 20 Apr 2020 22:23:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 242A9206DD for ; Mon, 20 Apr 2020 22:23:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726136AbgDTWXi (ORCPT ); Mon, 20 Apr 2020 18:23:38 -0400 Received: from mail104.syd.optusnet.com.au ([211.29.132.246]:47555 "EHLO mail104.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725774AbgDTWXi (ORCPT ); Mon, 20 Apr 2020 18:23:38 -0400 Received: from dread.disaster.area (pa49-180-0-232.pa.nsw.optusnet.com.au [49.180.0.232]) by mail104.syd.optusnet.com.au (Postfix) with ESMTPS id 2C29B5836FF; Tue, 21 Apr 2020 08:23:34 +1000 (AEST) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1jQepA-0006KZ-QY; Tue, 21 Apr 2020 08:23:32 +1000 Date: Tue, 21 Apr 2020 08:23:32 +1000 From: Dave Chinner To: Brian Foster Cc: linux-xfs@vger.kernel.org Subject: Re: [PATCH 05/12] xfs: ratelimit unmount time per-buffer I/O error warning Message-ID: <20200420222332.GP9800@dread.disaster.area> References: <20200417150859.14734-1-bfoster@redhat.com> <20200417150859.14734-6-bfoster@redhat.com> <20200420031959.GH9800@dread.disaster.area> <20200420140205.GE27516@bfoster> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200420140205.GE27516@bfoster> User-Agent: Mutt/1.10.1 (2018-07-13) X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.3 cv=QIgWuTDL c=1 sm=1 tr=0 a=XYjVcjsg+1UI/cdbgX7I7g==:117 a=XYjVcjsg+1UI/cdbgX7I7g==:17 a=kj9zAlcOel0A:10 a=cl8xLZFz6L8A:10 a=20KFwNOVAAAA:8 a=7-415B0cAAAA:8 a=BE_2l6gJ5e0v_kKrTcUA:9 a=CjuIK1q_8ugA:10 a=biEYGPWJfzWAr4FL6Ov7:22 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Mon, Apr 20, 2020 at 10:02:05AM -0400, Brian Foster wrote: > On Mon, Apr 20, 2020 at 01:19:59PM +1000, Dave Chinner wrote: > > On Fri, Apr 17, 2020 at 11:08:52AM -0400, Brian Foster wrote: > > > At unmount time, XFS emits a warning for every in-core buffer that > > > might have undergone a write error. In practice this behavior is > > > probably reasonable given that the filesystem is likely short lived > > > once I/O errors begin to occur consistently. Under certain test or > > > otherwise expected error conditions, this can spam the logs and slow > > > down the unmount. Ratelimit the warning to prevent this problem > > > while still informing the user that errors have occurred. > > > > > > Signed-off-by: Brian Foster > > > --- > > > fs/xfs/xfs_buf.c | 7 +++---- > > > 1 file changed, 3 insertions(+), 4 deletions(-) > > > > > > diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c > > > index 93942d8e35dd..5120fed06075 100644 > > > --- a/fs/xfs/xfs_buf.c > > > +++ b/fs/xfs/xfs_buf.c > > > @@ -1685,11 +1685,10 @@ xfs_wait_buftarg( > > > bp = list_first_entry(&dispose, struct xfs_buf, b_lru); > > > list_del_init(&bp->b_lru); > > > if (bp->b_flags & XBF_WRITE_FAIL) { > > > - xfs_alert(btp->bt_mount, > > > -"Corruption Alert: Buffer at daddr 0x%llx had permanent write failures!", > > > + xfs_alert_ratelimited(btp->bt_mount, > > > +"Corruption Alert: Buffer at daddr 0x%llx had permanent write failures!\n" > > > +"Please run xfs_repair to determine the extent of the problem.", > > > (long long)bp->b_bn); > > > > Hmmmm. I was under the impression that multiple line log messages > > were frowned upon because they prevent every output line in the log > > being tagged correctly. That's where KERN_CONT came from (i.e. it's > > a continuation of a previous log message), but we don't use that > > with the XFS logging and hence multi-line log messages are split > > into multiple logging calls. > > > > I debated combining these into a single line for that exact reason for > about a second and then just went with this because I didn't think it > mattered that much. It doesn't matter to us, but it does matter to those people who want their log entries correctly tagged for their classification engines... > > IOWs, this might be better handled just using a static ratelimit > > variable here.... > > > > Actually, we already have one for xfs_buf_item_push() to limit > > warnings about retrying XBF_WRITE_FAIL buffers: > > > > static DEFINE_RATELIMIT_STATE(xfs_buf_write_fail_rl_state, 30 * HZ, 10); > > > > Perhaps we should be using the same ratelimit variable here.... > > > > IIRC that was static in another file, but we can centralize (and perhaps > generalize..) it somewhere if that is preferred.. I think it makes sense to have all the buffer write fail messages ratelimited under the same variable - once it starts spewing messages, we should limit them all the same way... Cheers, Dave. -- Dave Chinner david@fromorbit.com