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=-0.9 required=3.0 tests=FORGED_MUA_MOZILLA, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 012ADC49ED6 for ; Tue, 10 Sep 2019 11:16:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D667B2089F for ; Tue, 10 Sep 2019 11:16:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392848AbfIJLQl (ORCPT ); Tue, 10 Sep 2019 07:16:41 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:19346 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729270AbfIJLQl (ORCPT ); Tue, 10 Sep 2019 07:16:41 -0400 Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x8ABBgLJ135365 for ; Tue, 10 Sep 2019 07:16:39 -0400 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0b-001b2d01.pphosted.com with ESMTP id 2ux8jevtct-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 10 Sep 2019 07:16:39 -0400 Received: from localhost by e06smtp01.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 10 Sep 2019 12:16:37 +0100 Received: from b06cxnps4074.portsmouth.uk.ibm.com (9.149.109.196) by e06smtp01.uk.ibm.com (192.168.101.131) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 10 Sep 2019 12:16:34 +0100 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x8ABGXf232833564 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 10 Sep 2019 11:16:33 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 2F0E74C044; Tue, 10 Sep 2019 11:16:33 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 08C5A4C052; Tue, 10 Sep 2019 11:16:31 +0000 (GMT) Received: from [9.199.159.63] (unknown [9.199.159.63]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 10 Sep 2019 11:16:30 +0000 (GMT) Subject: Re: [PATCH v2 2/6] ext4: move inode extension/truncate code out from ext4_iomap_end() To: Matthew Bobrowski Cc: tytso@mit.edu, jack@suse.cz, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, david@fromorbit.com, hch@infradead.org, darrick.wong@oracle.com References: <20190909081729.3555C42041@d06av24.portsmouth.uk.ibm.com> <20190910102643.GA9013@bobrowski> From: Ritesh Harjani Date: Tue, 10 Sep 2019 16:46:30 +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: <20190910102643.GA9013@bobrowski> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 19091011-4275-0000-0000-00000363EAB9 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19091011-4276-0000-0000-000038763E83 Message-Id: <20190910111631.08C5A4C052@d06av22.portsmouth.uk.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-09-10_07:,, 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-1909100113 Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On 9/10/19 3:56 PM, Matthew Bobrowski wrote: > On Mon, Sep 09, 2019 at 01:47:28PM +0530, Ritesh Harjani wrote: >> On 9/9/19 4:49 AM, Matthew Bobrowski wrote: >>> +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); > > I don't believe that would be entirely correct. The reason being is that the > 'end_blk' is meant to represent the last logical block which we should expect > to have used for the write operation. So, we have the 'offset' which > represents starting point, 'len' which is the amount of data that has been > written, and 'count' which is the amount of data that we still have left over > in the 'iter', if any. > Agree. Yes, I see that you are passing iov_iter_count(from) as a param, after the dax write. > The count in the 'iter' is decremented as that data is copied from it. So if > we did use 'offset' + 'count', in the instance of a short write, we > potentially wouldn't truncate any of the allocated but not written blocks. I > guess this would hold true for the DAX code path at this point, seeing as > though for the DIO case we pass in '0'. Agreed. > >>> +/* >>> + * 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;` > > True. > > ---- >