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=-8.3 required=3.0 tests=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 1332CC31E40 for ; Tue, 13 Aug 2019 02:40:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D14A420673 for ; Tue, 13 Aug 2019 02:40:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726506AbfHMCko (ORCPT ); Mon, 12 Aug 2019 22:40:44 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:4664 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726483AbfHMCko (ORCPT ); Mon, 12 Aug 2019 22:40:44 -0400 Received: from DGGEMS407-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 5BDD9F756FE5AB8BEAEB; Tue, 13 Aug 2019 10:40:42 +0800 (CST) Received: from [10.134.22.195] (10.134.22.195) by smtp.huawei.com (10.3.19.207) with Microsoft SMTP Server (TLS) id 14.3.439.0; Tue, 13 Aug 2019 10:40:38 +0800 Subject: Re: [PATCH 3/6] f2fs: skip truncate when verity in progress in ->write_begin() To: , , References: <20190811213557.1970-1-ebiggers@kernel.org> <20190811213557.1970-4-ebiggers@kernel.org> <20190812225848.GA175194@gmail.com> From: Chao Yu Message-ID: <13be698c-1a3d-9f6a-66d8-b9024b7963f3@huawei.com> Date: Tue, 13 Aug 2019 10:40:39 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20190812225848.GA175194@gmail.com> Content-Type: text/plain; charset="windows-1252" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.134.22.195] X-CFilter-Loop: Reflected Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Hi Eric, On 2019/8/13 6:58, Eric Biggers wrote: > Hi Chao, > > On Mon, Aug 12, 2019 at 08:25:33PM +0800, Chao Yu wrote: >> Hi Eric, >> >> On 2019/8/12 5:35, Eric Biggers wrote: >>> From: Eric Biggers >>> >>> When an error (e.g. ENOSPC) occurs during f2fs_write_begin() when called >>> from f2fs_write_merkle_tree_block(), skip truncating the file. i_size >>> is not meaningful in this case, and the truncation is handled by >>> f2fs_end_enable_verity() instead. >>> >>> Fixes: 60d7bf0f790f ("f2fs: add fs-verity support") >>> Signed-off-by: Eric Biggers >>> --- >>> fs/f2fs/data.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c >>> index 3f525f8a3a5fa..00b03fb87bd9b 100644 >>> --- a/fs/f2fs/data.c >>> +++ b/fs/f2fs/data.c >>> @@ -2476,7 +2476,7 @@ static void f2fs_write_failed(struct address_space *mapping, loff_t to) >>> struct inode *inode = mapping->host; >>> loff_t i_size = i_size_read(inode); >>> >>> - if (to > i_size) { >> >> Maybe adding one single line comment to mention that it's redundant/unnecessary >> truncation here is better, if I didn't misunderstand this. >> >> Thanks, >> >>> + if (to > i_size && !f2fs_verity_in_progress(inode)) { >>> down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); >>> down_write(&F2FS_I(inode)->i_mmap_sem); >>> > > Do you mean add a comment instead of the !f2fs_verity_in_progress() check, or in > addition to it? ->write_begin(), ->writepages(), and ->write_end() are all Sorry, I didn't make this very clear, I meant adding the comment in addition on above change. > supposed to ignore i_size when verity is in progress, so I don't think this > particular part should be different, even if technically it's still correct to > truncate twice. Also, ext4 needs this check in its ->write_begin() for locking > reasons; we should keep f2fs similar. Agreed. > > How about having both a comment and the check, like: > > /* In the fs-verity case, f2fs_end_enable_verity() does the truncate */ > if (to > i_size && !f2fs_verity_in_progress(inode)) { The comment looks good to me. :) Thanks, > > - Eric > . >