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 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 62268C433E0 for ; Thu, 25 Jun 2020 12:26:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3992E20709 for ; Thu, 25 Jun 2020 12:26:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="XFXGdHnv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404518AbgFYM0a (ORCPT ); Thu, 25 Jun 2020 08:26:30 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:36204 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2404343AbgFYM0a (ORCPT ); Thu, 25 Jun 2020 08:26:30 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593087989; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=aYXtlBUY/pJPnqGvJ91dbHa8LabvsfdbqBnRqhm24CY=; b=XFXGdHnvwAIeY+z8+vxR5c1NeG29Js+aZTkOXwMHQddBaQc8dM69BsPpx57kkfBSS8ZnW3 ie8jjCf0QJiBbsCc83q2TelvPy+JJxSTA7kDtqWfdxLXQIkESKDDdl1fPawDrn4uZ5ZqtQ HdmDMhQ9P9JmVVM7cF88VGlV3fZWrug= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-467-RRQnviqjNgmj5KlCyuAvwg-1; Thu, 25 Jun 2020 08:26:26 -0400 X-MC-Unique: RRQnviqjNgmj5KlCyuAvwg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3B09618FE860; Thu, 25 Jun 2020 12:26:25 +0000 (UTC) Received: from bfoster (dhcp-41-2.bos.redhat.com [10.18.41.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C3CDB8FF97; Thu, 25 Jun 2020 12:26:24 +0000 (UTC) Date: Thu, 25 Jun 2020 08:26:23 -0400 From: Brian Foster To: "Darrick J. Wong" Cc: xfs , Dave Chinner Subject: Re: [PATCH v4] xfs: don't eat an EIO/ENOSPC writeback error when scrubbing data fork Message-ID: <20200625122623.GB2863@bfoster> References: <20200625011643.GJ7625@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200625011643.GJ7625@magnolia> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Wed, Jun 24, 2020 at 06:16:43PM -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 > --- > v4: remove if block that only had a gigantic comment > v3: don't play this game where we clear the mapping error only to re-set it > v2: explain why it's ok to keep going even if writeback fails > --- Reviewed-by: Brian Foster > fs/xfs/scrub/bmap.c | 22 ++++++++++++++++++++-- > 1 file changed, 20 insertions(+), 2 deletions(-) > > diff --git a/fs/xfs/scrub/bmap.c b/fs/xfs/scrub/bmap.c > index 7badd6dfe544..955302e7cdde 100644 > --- a/fs/xfs/scrub/bmap.c > +++ b/fs/xfs/scrub/bmap.c > @@ -45,9 +45,27 @@ xchk_setup_inode_bmap( > */ > if (S_ISREG(VFS_I(sc->ip)->i_mode) && > sc->sm->sm_type == XFS_SCRUB_TYPE_BMBTD) { > + struct address_space *mapping = VFS_I(sc->ip)->i_mapping; > + > inode_dio_wait(VFS_I(sc->ip)); > - error = filemap_write_and_wait(VFS_I(sc->ip)->i_mapping); > - if (error) > + > + /* > + * Try to flush all incore state to disk before we examine the > + * space mappings for the data fork. Leave accumulated errors > + * in the mapping for the writer threads to consume. > + * > + * On ENOSPC or EIO writeback errors, 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. We can handle delalloc > + * extents in the scrubber, so leaving them in memory is fine. > + */ > + error = filemap_fdatawrite(mapping); > + if (!error) > + error = filemap_fdatawait_keep_errors(mapping); > + if (error && (error != -ENOSPC && error != -EIO)) > goto out; > } > >