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=-10.1 required=3.0 tests=BAYES_00,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=unavailable 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 717A5C433E4 for ; Mon, 13 Jul 2020 15:41:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 52B0C20773 for ; Mon, 13 Jul 2020 15:41:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="PUIhQFX2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729806AbgGMPlr (ORCPT ); Mon, 13 Jul 2020 11:41:47 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:52344 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729492AbgGMPlq (ORCPT ); Mon, 13 Jul 2020 11:41:46 -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 06DFfQaC116946; Mon, 13 Jul 2020 15:41:26 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=r/x6t9b6PiVKSC8Zl/RQEKSFbRTLrQyIYq8XvVgqckw=; b=PUIhQFX2qzKwxNAVgMbGEStsD0pPLA4VldY4fFzqyPvHBvhJY6djsFcZ/qpEgFjxKpW2 VjWwENGHb+FRhdEdxpC1g1oyTWx6IiKQh/E9ifBy9OYvBpjj2b46R2pm+B1Vg7Dg5upr zvO1Z6SXgjJOn+JOfawb3wsVc5ZOwjXlhsF3pra+CPuSY0OLRB9EMXszR3zwv/SPqGMz jRBKlN//3VIJhhvuZi0gwX5Eyob/sbfHmsueZbrFeqljLGpCOIhki5G1R+xb23DRt4A7 6E5rqnVWFUUwD2L0wbS+sChDael3Iwz/GWuKemMZ7S+3aYNe/eu8R7BnachdbXdIenpU Bg== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by userp2120.oracle.com with ESMTP id 32762n7pvr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 13 Jul 2020 15:41:26 +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 06DFXYcR135052; Mon, 13 Jul 2020 15:39:26 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userp3020.oracle.com with ESMTP id 327q6qfa2s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 13 Jul 2020 15:39:26 +0000 Received: from abhmp0004.oracle.com (abhmp0004.oracle.com [141.146.116.10]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 06DFdMk1026054; Mon, 13 Jul 2020 15:39:22 GMT Received: from localhost (/67.169.218.210) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 13 Jul 2020 08:39:22 -0700 Date: Mon, 13 Jul 2020 08:39:20 -0700 From: "Darrick J. Wong" To: Christoph Hellwig Cc: Dave Chinner , Goldwyn Rodrigues , Damien Le Moal , Naohiro Aota , Johannes Thumshirn , Matthew Wilcox , linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, cluster-devel@redhat.com, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org Subject: Re: [PATCH 2/2] iomap: fall back to buffered writes for invalidation failures Message-ID: <20200713153920.GU7606@magnolia> References: <20200713074633.875946-1-hch@lst.de> <20200713074633.875946-3-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200713074633.875946-3-hch@lst.de> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9681 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 suspectscore=5 phishscore=0 malwarescore=0 mlxlogscore=999 bulkscore=0 mlxscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007130115 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9681 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 malwarescore=0 spamscore=0 clxscore=1011 priorityscore=1501 mlxlogscore=999 lowpriorityscore=0 bulkscore=0 suspectscore=5 phishscore=0 adultscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007130115 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, Jul 13, 2020 at 09:46:33AM +0200, Christoph Hellwig wrote: > Failing to invalid the page cache means data in incoherent, which is > a very bad state for the system. Always fall back to buffered I/O > through the page cache if we can't invalidate mappings. > > Signed-off-by: Christoph Hellwig > --- > fs/ext4/file.c | 2 ++ > fs/gfs2/file.c | 3 ++- > fs/iomap/direct-io.c | 13 ++++++++----- > fs/iomap/trace.h | 1 + > fs/xfs/xfs_file.c | 4 ++-- > fs/zonefs/super.c | 7 +++++-- > 6 files changed, 20 insertions(+), 10 deletions(-) > > diff --git a/fs/ext4/file.c b/fs/ext4/file.c > index 2a01e31a032c4c..0da6c2a2c32c1e 100644 > --- a/fs/ext4/file.c > +++ b/fs/ext4/file.c > @@ -544,6 +544,8 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from) > iomap_ops = &ext4_iomap_overwrite_ops; > ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops, > is_sync_kiocb(iocb) || unaligned_io || extend); > + if (ret == -EREMCHG) > + ret = 0; > > if (extend) > ret = ext4_handle_inode_extension(inode, offset, ret, count); > diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c > index fe305e4bfd3734..c7907d40c61d17 100644 > --- a/fs/gfs2/file.c > +++ b/fs/gfs2/file.c > @@ -814,7 +814,8 @@ static ssize_t gfs2_file_direct_write(struct kiocb *iocb, struct iov_iter *from) > > ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL, > is_sync_kiocb(iocb)); > - > + if (ret == -EREMCHG) > + ret = 0; > out: > gfs2_glock_dq(&gh); > out_uninit: > diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c > index 190967e87b69e4..62626235cdbe8d 100644 > --- a/fs/iomap/direct-io.c > +++ b/fs/iomap/direct-io.c > @@ -10,6 +10,7 @@ > #include > #include > #include > +#include "trace.h" > > #include "../internal.h" > > @@ -478,13 +479,15 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, > if (iov_iter_rw(iter) == WRITE) { > /* > * Try to invalidate cache pages for the range we are writing. > - * If this invalidation fails, tough, the write will still work, > - * but racing two incompatible write paths is a pretty crazy > - * thing to do, so we don't support it 100%. > + * If this invalidation fails, let the caller fall back to > + * buffered I/O. > */ > if (invalidate_inode_pages2_range(mapping, pos >> PAGE_SHIFT, > - end >> PAGE_SHIFT)) > - dio_warn_stale_pagecache(iocb->ki_filp); > + end >> PAGE_SHIFT)) { > + trace_iomap_dio_invalidate_fail(inode, pos, count); > + ret = -EREMCHG; -ENOTBLK is already being used as a "magic" return code that means "retry this direct write as a buffered write". Shouldn't we use that instead? -EREMCHG was a private hack we put in XFS for the one case where a direct write had to be done through the page cache (non block-aligned COW), but maybe it's time we put that to rest since the rest of the world apparently thinks the magic fallback code is -ENOTBLK. --D > + goto out_free_dio; > + } > > if (!wait_for_completion && !inode->i_sb->s_dio_done_wq) { > ret = sb_init_dio_done_wq(inode->i_sb); > diff --git a/fs/iomap/trace.h b/fs/iomap/trace.h > index 5693a39d52fb63..fdc7ae388476f5 100644 > --- a/fs/iomap/trace.h > +++ b/fs/iomap/trace.h > @@ -74,6 +74,7 @@ DEFINE_EVENT(iomap_range_class, name, \ > DEFINE_RANGE_EVENT(iomap_writepage); > DEFINE_RANGE_EVENT(iomap_releasepage); > DEFINE_RANGE_EVENT(iomap_invalidatepage); > +DEFINE_RANGE_EVENT(iomap_dio_invalidate_fail); > > #define IOMAP_TYPE_STRINGS \ > { IOMAP_HOLE, "HOLE" }, \ > diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c > index 00db81eac80d6c..551cca39fa3ba6 100644 > --- a/fs/xfs/xfs_file.c > +++ b/fs/xfs/xfs_file.c > @@ -553,8 +553,8 @@ xfs_file_dio_aio_write( > xfs_iunlock(ip, iolock); > > /* > - * No fallback to buffered IO on errors for XFS, direct IO will either > - * complete fully or fail. > + * No partial fallback to buffered IO on errors for XFS, direct IO will > + * either complete fully or fail. > */ > ASSERT(ret < 0 || ret == count); > return ret; > diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c > index 07bc42d62673ce..793850454b752f 100644 > --- a/fs/zonefs/super.c > +++ b/fs/zonefs/super.c > @@ -786,8 +786,11 @@ static ssize_t zonefs_file_write_iter(struct kiocb *iocb, struct iov_iter *from) > if (iocb->ki_pos >= ZONEFS_I(inode)->i_max_size) > return -EFBIG; > > - if (iocb->ki_flags & IOCB_DIRECT) > - return zonefs_file_dio_write(iocb, from); > + if (iocb->ki_flags & IOCB_DIRECT) { > + ret = zonefs_file_dio_write(iocb, from); > + if (ret != -EREMCHG) > + return ret; > + } > > return zonefs_file_buffered_write(iocb, from); > } > -- > 2.26.2 >