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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY 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 8CFAEC433E0 for ; Mon, 22 Jun 2020 23:28:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 64D1320786 for ; Mon, 22 Jun 2020 23:28:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="LJQGSGd+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728775AbgFVX2s (ORCPT ); Mon, 22 Jun 2020 19:28:48 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:60484 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728580AbgFVX2s (ORCPT ); Mon, 22 Jun 2020 19:28:48 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 05MNRoKV143381; Mon, 22 Jun 2020 23:28:45 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2020-01-29; bh=TdM/QuisLNteK7xxGk3iNVJpWHhgOushQYRVHK9hrJc=; b=LJQGSGd+2fjPKhd7aQyv/mpqdurOzJdtiLwBQgTCoC9KKd5f0XPF228F0505e5Fjzs5O Qv8SMd6ZNZtAO2uIcRgMjiHMMIibGpuI72d9ZUHu1UAcFs/yneTz2S8Jd+vYaOXhH0UJ 69zopMfUjdjwXuWQewsKVoucA7gloqefw7Y7qZgN57Z0da82FPXpPqDYO9W62ZafIPbg mBjZVjK1BS9DATsTNc5pBYpu3P9Us6BfKr1/3v/qF0acRFfhctsDkbD1w8vPU5BA9ph8 w1XfRb3YB50Op67+/yu8DFqJklEMHpRYF336eyyO1Sx4vzvfZMSW7THhwOvl1v8OUmG3 3w== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by userp2120.oracle.com with ESMTP id 31sebbj5hy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 22 Jun 2020 23:28:45 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 05MNO6x5163999; Mon, 22 Jun 2020 23:28:45 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userp3020.oracle.com with ESMTP id 31sv7qv78v-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 22 Jun 2020 23:28:45 +0000 Received: from abhmp0001.oracle.com (abhmp0001.oracle.com [141.146.116.7]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 05MNSiCA001566; Mon, 22 Jun 2020 23:28:44 GMT Received: from localhost (/67.169.218.210) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 22 Jun 2020 23:28:43 +0000 Date: Mon, 22 Jun 2020 16:28:43 -0700 From: "Darrick J. Wong" To: Dave Chinner Cc: xfs Subject: Re: [PATCH] xfs: don't eat an EIO/ENOSPC writeback error when scrubbing data fork Message-ID: <20200622232843.GA7625@magnolia> References: <20200622171713.GG11245@magnolia> <20200622220839.GV2005@dread.disaster.area> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200622220839.GV2005@dread.disaster.area> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9660 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 suspectscore=1 mlxlogscore=999 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006220155 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9660 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 malwarescore=0 phishscore=0 adultscore=0 impostorscore=0 cotscore=-2147483648 mlxscore=0 suspectscore=1 mlxlogscore=999 bulkscore=0 lowpriorityscore=0 clxscore=1015 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006220155 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Tue, Jun 23, 2020 at 08:08:39AM +1000, Dave Chinner wrote: > On Mon, Jun 22, 2020 at 10:17:13AM -0700, Darrick J. Wong wrote: > > From: Darrick J. Wong > > > > The data fork scrubber calls filemap_write_and_wait to flush dirty pages > > and delalloc reservations out to disk prior to checking the data fork's > > extent mappings. Unfortunately, this means that scrub can consume the > > EIO/ENOSPC errors that would otherwise have stayed around in the address > > space until (we hope) the writer application calls fsync to persist data > > and collect errors. The end result is that programs that wrote to a > > file might never see the error code and proceed as if nothing were > > wrong. > > > > xfs_scrub is not in a position to notify file writers about the > > writeback failure, and it's only here to check metadata, not file > > contents. Therefore, if writeback fails, we should stuff the error code > > back into the address space so that an fsync by the writer application > > can pick that up. > > > > Fixes: 99d9d8d05da2 ("xfs: scrub inode block mappings") > > Signed-off-by: Darrick J. Wong > > --- > > fs/xfs/scrub/bmap.c | 10 +++++++++- > > 1 file changed, 9 insertions(+), 1 deletion(-) > > > > diff --git a/fs/xfs/scrub/bmap.c b/fs/xfs/scrub/bmap.c > > index 7badd6dfe544..03be7cf3fe5a 100644 > > --- a/fs/xfs/scrub/bmap.c > > +++ b/fs/xfs/scrub/bmap.c > > @@ -47,7 +47,15 @@ xchk_setup_inode_bmap( > > sc->sm->sm_type == XFS_SCRUB_TYPE_BMBTD) { > > inode_dio_wait(VFS_I(sc->ip)); > > error = filemap_write_and_wait(VFS_I(sc->ip)->i_mapping); > > - if (error) > > + if (error == -ENOSPC || error == -EIO) { > > + /* > > + * If writeback hits EIO or ENOSPC, reflect it back > > + * into the address space mapping so that a writer > > + * program calling fsync to look for errors will still > > + * capture the error. > > + */ > > + mapping_set_error(VFS_I(sc->ip)->i_mapping, error); > > + } else if (error) > > goto out; > > calling mapping_set_error() seems reasonable here and you've > explained that well, but shouldn't the error then be processed the > same way as all other errors? i.e. by jumping to out? > > If we are now continuing to scrub the bmap after ENOSPC/EIO occur, > why? Heh, ok, more explanation is needed. How about this? /* * If writeback hits EIO or ENOSPC, reflect it back into the * address space mapping so that a writer program calling fsync * to look for errors will still capture the error. * * However, we continue into the extent mapping checks because * write failures do not necessarily imply anything about the * correctness of the file metadata. The metadata and the file * data could be on completely separate devices; a media failure * might only affect a subset of the disk, etc. */ --D > Cheers, > > Dave. > -- > Dave Chinner > david@fromorbit.com