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=-9.9 required=3.0 tests=BAYES_00,FORGED_MUA_MOZILLA, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 594A3C433DF for ; Fri, 31 Jul 2020 07:01:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 440D121883 for ; Fri, 31 Jul 2020 07:01:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731648AbgGaHBc (ORCPT ); Fri, 31 Jul 2020 03:01:32 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:19692 "EHLO mx0b-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731384AbgGaHBb (ORCPT ); Fri, 31 Jul 2020 03:01:31 -0400 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 06V6WCoY059876; Fri, 31 Jul 2020 03:01:17 -0400 Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 32mc8wk8nc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 31 Jul 2020 03:01:17 -0400 Received: from m0098417.ppops.net (m0098417.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 06V6oCOo103706; Fri, 31 Jul 2020 03:01:16 -0400 Received: from ppma02fra.de.ibm.com (47.49.7a9f.ip4.static.sl-reverse.com [159.122.73.71]) by mx0a-001b2d01.pphosted.com with ESMTP id 32mc8wk8mh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 31 Jul 2020 03:01:16 -0400 Received: from pps.filterd (ppma02fra.de.ibm.com [127.0.0.1]) by ppma02fra.de.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 06V70YTs023783; Fri, 31 Jul 2020 07:01:14 GMT Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by ppma02fra.de.ibm.com with ESMTP id 32gcq0v9c4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 31 Jul 2020 07:01:14 +0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 06V71BHi25362690 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 31 Jul 2020 07:01:11 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 614075205A; Fri, 31 Jul 2020 07:01:11 +0000 (GMT) Received: from localhost.localdomain (unknown [9.199.33.112]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 1B13252079; Fri, 31 Jul 2020 07:01:08 +0000 (GMT) Subject: Re: [PATCH 3/3] iomap: fall back to buffered writes for invalidation failures To: Christoph Hellwig , Dave Chinner , Goldwyn Rodrigues Cc: 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, Dave Chinner , Goldwyn Rodrigues References: <20200721183157.202276-1-hch@lst.de> <20200721183157.202276-4-hch@lst.de> From: Ritesh Harjani Date: Fri, 31 Jul 2020 12:31:08 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200721183157.202276-4-hch@lst.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Message-Id: <20200731070109.1B13252079@d06av21.portsmouth.uk.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-07-31_01:2020-07-30,2020-07-31 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 clxscore=1011 impostorscore=0 mlxscore=0 spamscore=0 adultscore=0 phishscore=0 lowpriorityscore=0 suspectscore=2 bulkscore=0 mlxlogscore=999 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007310045 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 7/22/20 12:01 AM, 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 > Acked-by: Dave Chinner > Reviewed-by: Goldwyn Rodrigues Reviewed-by: Ritesh Harjani mainly for ext4 part. > --- > fs/ext4/file.c | 2 ++ > fs/gfs2/file.c | 3 ++- > fs/iomap/direct-io.c | 16 +++++++++++----- > fs/iomap/trace.h | 1 + > fs/xfs/xfs_file.c | 4 ++-- > fs/zonefs/super.c | 7 +++++-- > 6 files changed, 23 insertions(+), 10 deletions(-) > > diff --git a/fs/ext4/file.c b/fs/ext4/file.c > index 2a01e31a032c4c..129cc1dd6b7952 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 == -ENOTBLK) > + 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 bebde537ac8cf2..b085a3bea4f0fd 100644 > --- a/fs/gfs2/file.c > +++ b/fs/gfs2/file.c > @@ -835,7 +835,8 @@ 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 == -ENOTBLK) > + 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..c1aafb2ab99072 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" > > @@ -401,6 +402,9 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, > * can be mapped into multiple disjoint IOs and only a subset of the IOs issued > * may be pure data writes. In that case, we still need to do a full data sync > * completion. > + * > + * Returns -ENOTBLK In case of a page invalidation invalidation failure for > + * writes. The callers needs to fall back to buffered I/O in this case. > */ > ssize_t > iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, > @@ -478,13 +482,15 @@ 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 = -ENOTBLK; > + goto out_free_dio; > + } > > if (!wait_for_completion && !inode->i_sb->s_dio_done_wq) { > ret = sb_init_dio_done_wq(inode->i_sb); Just as a note. So if the driver returns -ENOTBLK (from ->iomap_end)then iomap considers it as a magic value to fall back to buffered-io and it changes ret=0 And now with this patch, iomap could also return -ENOTBLK if it gets an error while doing above operation and so the driver is free to consider this as a fallback mechanism to buffered-io.