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=-6.9 required=3.0 tests=FORGED_MUA_MOZILLA, 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 05A1CC00307 for ; Mon, 9 Sep 2019 08:17:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C073420678 for ; Mon, 9 Sep 2019 08:17:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726492AbfIIIRj (ORCPT ); Mon, 9 Sep 2019 04:17:39 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:35052 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726142AbfIIIRj (ORCPT ); Mon, 9 Sep 2019 04:17:39 -0400 Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x898Gl92025171 for ; Mon, 9 Sep 2019 04:17:37 -0400 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0b-001b2d01.pphosted.com with ESMTP id 2uwj3xjukb-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 09 Sep 2019 04:17:36 -0400 Received: from localhost by e06smtp03.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 9 Sep 2019 09:17:31 +0100 Received: from d06av24.portsmouth.uk.ibm.com (d06av24.portsmouth.uk.ibm.com [9.149.105.60]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x898HUkb45875376 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 9 Sep 2019 08:17:30 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C56AD42047; Mon, 9 Sep 2019 08:17:30 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3555C42041; Mon, 9 Sep 2019 08:17:29 +0000 (GMT) Received: from [9.199.158.183] (unknown [9.199.158.183]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Mon, 9 Sep 2019 08:17:29 +0000 (GMT) Subject: Re: [PATCH v2 2/6] ext4: move inode extension/truncate code out from ext4_iomap_end() To: Matthew Bobrowski , tytso@mit.edu, jack@suse.cz, adilger.kernel@dilger.ca Cc: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, david@fromorbit.com, hch@infradead.org, darrick.wong@oracle.com References: From: Ritesh Harjani Date: Mon, 9 Sep 2019 13:47:28 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 19090908-0012-0000-0000-00000348AA0C X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19090908-0013-0000-0000-000021830932 Message-Id: <20190909081729.3555C42041@d06av24.portsmouth.uk.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-09-09_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=667 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1909090090 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 9/9/19 4:49 AM, Matthew Bobrowski wrote: > In preparation for implementing the iomap direct IO write path > modifications, the inode extension/truncate code needs to be moved out > from ext4_iomap_end(). For direct IO, if the current code remained > within ext4_iomap_end() it would behave incorrectly. If we update the > inode size prior to converting unwritten extents we run the risk of > allowing a racing direct IO read operation to find unwritten extents > before they are converted. > > The inode extension/truncate code has been moved out into a new helper > ext4_handle_inode_extension(). This helper has been designed so that > it can be used by both DAX and direct IO paths in the instance that > the result of the write is extending the inode. > > Signed-off-by: Matthew Bobrowski > --- > fs/ext4/file.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++- > fs/ext4/inode.c | 48 +------------------------ > 2 files changed, 93 insertions(+), 48 deletions(-) > > diff --git a/fs/ext4/file.c b/fs/ext4/file.c > index e52e3928dc25..8e586198f6e6 100644 > --- a/fs/ext4/file.c > +++ b/fs/ext4/file.c > @@ -33,6 +33,7 @@ > #include "ext4_jbd2.h" > #include "xattr.h" > #include "acl.h" > +#include "truncate.h" > > static bool ext4_dio_checks(struct inode *inode) > { > @@ -233,12 +234,91 @@ static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from) > return iov_iter_count(from); > } > > +static int ext4_handle_inode_extension(struct inode *inode, loff_t offset, > + ssize_t len, size_t count) > +{ > + handle_t *handle; > + bool truncate = false; > + ext4_lblk_t written_blk, end_blk; > + int ret = 0, blkbits = inode->i_blkbits; > + > + handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); > + if (IS_ERR(handle)) { > + ret = PTR_ERR(handle); > + goto orphan_del; > + } > + > + if (ext4_update_inode_size(inode, offset + len)) > + ext4_mark_inode_dirty(handle, inode); > + > + /* > + * We may need truncate allocated but not written blocks > + * beyond EOF. > + */ > + written_blk = ALIGN(offset + len, 1 << blkbits); > + end_blk = ALIGN(offset + len + count, 1 << blkbits); why add len in end_blk calculation? shouldn't this be like below? end_blk = ALIGN(offset + count, 1 << blkbits); > + if (written_blk < end_blk && ext4_can_truncate(inode)) > + truncate = true; > + > + /* > + * Remove the inode from the orphan list if it has been > + * extended and everything went OK. > + */ > + if (!truncate && inode->i_nlink) > + ext4_orphan_del(handle, inode); > + ext4_journal_stop(handle); > + > + if (truncate) { > + ext4_truncate_failed_write(inode); > +orphan_del: > + /* > + * If the truncate operation failed early the inode > + * may still be on the orphan list. In that case, we > + * need try remove the inode from the linked list in > + * memory. > + */ > + if (inode->i_nlink) > + ext4_orphan_del(NULL, inode); > + } > + return ret; > +} > + > +/* > + * The inode may have been placed onto the orphan list or has had > + * blocks allocated beyond EOF as a result of an extension. We need to > + * ensure that any necessary cleanup routines are performed if the > + * error path has been taken for a write. > + */ > +static int ext4_handle_failed_inode_extension(struct inode *inode, loff_t size) > +{ > + int ret = 0; No need of ret anyways. > + handle_t *handle; > + > + if (size > i_size_read(inode)) > + ext4_truncate_failed_write(inode); > + > + if (!list_empty(&EXT4_I(inode)->i_orphan)) { > + handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); > + if (IS_ERR(handle)) { > + if (inode->i_nlink) > + ext4_orphan_del(NULL, inode); > + return PTR_ERR(handle); > + } > + if (inode->i_nlink) > + ext4_orphan_del(handle, inode); > + ext4_journal_stop(handle); > + } > + return ret; can directly call for `return 0;` > +} > + > #ifdef CONFIG_FS_DAX > static ssize_t > ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) > { > - struct inode *inode = file_inode(iocb->ki_filp); > ssize_t ret; > + int error = 0; > + loff_t offset; > + struct inode *inode = file_inode(iocb->ki_filp); > > if (!inode_trylock(inode)) { > if (iocb->ki_flags & IOCB_NOWAIT) > @@ -255,7 +335,18 @@ ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) > if (ret) > goto out; > > + offset = iocb->ki_pos; > ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops); > + if (ret > 0 && iocb->ki_pos > i_size_read(inode)) > + error = ext4_handle_inode_extension(inode, offset, ret, > + iov_iter_count(from)); > + > + if (ret < 0) > + error = ext4_handle_failed_inode_extension(inode, > + iocb->ki_pos); > + > + if (error) > + ret = error; > out: > inode_unlock(inode); > if (ret > 0) > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index 420fe3deed39..761ce6286b05 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -3601,53 +3601,7 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, > static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length, > ssize_t written, unsigned flags, struct iomap *iomap) > { > - int ret = 0; > - handle_t *handle; > - int blkbits = inode->i_blkbits; > - bool truncate = false; > - > - if (!(flags & IOMAP_WRITE) || (flags & IOMAP_FAULT)) > - return 0; > - > - handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); > - if (IS_ERR(handle)) { > - ret = PTR_ERR(handle); > - goto orphan_del; > - } > - if (ext4_update_inode_size(inode, offset + written)) > - ext4_mark_inode_dirty(handle, inode); > - /* > - * We may need to truncate allocated but not written blocks beyond EOF. > - */ > - if (iomap->offset + iomap->length > > - ALIGN(inode->i_size, 1 << blkbits)) { > - ext4_lblk_t written_blk, end_blk; > - > - written_blk = (offset + written) >> blkbits; > - end_blk = (offset + length) >> blkbits; > - if (written_blk < end_blk && ext4_can_truncate(inode)) > - truncate = true; > - } > - /* > - * Remove inode from orphan list if we were extending a inode and > - * everything went fine. > - */ > - if (!truncate && inode->i_nlink && > - !list_empty(&EXT4_I(inode)->i_orphan)) > - ext4_orphan_del(handle, inode); > - ext4_journal_stop(handle); > - if (truncate) { > - ext4_truncate_failed_write(inode); > -orphan_del: > - /* > - * If truncate failed early the inode might still be on the > - * orphan list; we need to make sure the inode is removed from > - * the orphan list in that case. > - */ > - if (inode->i_nlink) > - ext4_orphan_del(NULL, inode); > - } > - return ret; > + return 0; > } > > const struct iomap_ops ext4_iomap_ops = { >