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=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,UNWANTED_LANGUAGE_BODY, 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 A7206C07E98 for ; Mon, 5 Jul 2021 06:32:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7B0EE613B0 for ; Mon, 5 Jul 2021 06:32:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229893AbhGEGex (ORCPT ); Mon, 5 Jul 2021 02:34:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:54040 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229797AbhGEGeu (ORCPT ); Mon, 5 Jul 2021 02:34:50 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 33710613B1; Mon, 5 Jul 2021 06:32:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625466734; bh=qXNW2ZG7c5MVDWbUdh+dqGa/9/WrXi9VqrWCyzq3bU4=; h=Subject:To:References:From:Cc:Date:In-Reply-To:From; b=lkoAWC+H3zK6SxYfMtkBOd+wWpYxBXLd4f57oSQKBLVj1mUVp48lDe2z5yh7DktxD 1ntPtNP5APymp1A9r0lrO3t5xW49q/ptdebZUpUHI1unI6w+FPWQYMrKI1UTt0Fkar /ik8umHQtCf182XDnn/RGGtWV/Hv8U0z9Z8w52qioxc41LMcLcby0IDNnE9VEAVHBW Z3iYdMU1uAH2VeqpY34kNdn9i/w4i51sPY8aid4ToBFxFvLV61DGV3V+bBkueXIGxF 55O1xQe/kd2F0FlwUDQI14b/cXM0gCbYYGSnWYwBDUnS7b9cIyD5L3q/tH8YPAA4tc Huxi330aCPl3A== Subject: Re: [f2fs-dev] [PATCH] f2fs: initialize page->private when using for our internal use To: Jaegeuk Kim References: <20210705052216.831989-1-jaegeuk@kernel.org> From: Chao Yu Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, Matthew Wilcox Message-ID: Date: Mon, 5 Jul 2021 14:32:11 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210705052216.831989-1-jaegeuk@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/7/5 13:22, Jaegeuk Kim wrote: > We need to guarantee it's initially zero. Otherwise, it'll hurt entire flag > operations. Oops, I didn't get the point, shouldn't .private be zero after page was just allocated by filesystem? What's the case we will encounter stall private data left in page? Cc Matthew Wilcox. Thanks, > > Fixes: b763f3bedc2d ("f2fs: restructure f2fs page.private layout") > Signed-off-by: Jaegeuk Kim > --- > fs/f2fs/data.c | 2 ++ > fs/f2fs/f2fs.h | 5 ++++- > 2 files changed, 6 insertions(+), 1 deletion(-) > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index 3a01a1b50104..d2cf48c5a2e4 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -3819,6 +3819,8 @@ int f2fs_migrate_page(struct address_space *mapping, > get_page(newpage); > } > > + /* guarantee to start from no stale private field */ > + set_page_private(newpage, 0); > if (PagePrivate(page)) { > set_page_private(newpage, page_private(page)); > SetPagePrivate(newpage); > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index 65befc68d88e..ee8eb33e2c25 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -1331,7 +1331,8 @@ enum { > #define PAGE_PRIVATE_GET_FUNC(name, flagname) \ > static inline bool page_private_##name(struct page *page) \ > { \ > - return test_bit(PAGE_PRIVATE_NOT_POINTER, &page_private(page)) && \ > + return PagePrivate(page) && \ > + test_bit(PAGE_PRIVATE_NOT_POINTER, &page_private(page)) && \ > test_bit(PAGE_PRIVATE_##flagname, &page_private(page)); \ > } > > @@ -1341,6 +1342,7 @@ static inline void set_page_private_##name(struct page *page) \ > if (!PagePrivate(page)) { \ > get_page(page); \ > SetPagePrivate(page); \ > + set_page_private(page, 0); \ > } \ > set_bit(PAGE_PRIVATE_NOT_POINTER, &page_private(page)); \ > set_bit(PAGE_PRIVATE_##flagname, &page_private(page)); \ > @@ -1392,6 +1394,7 @@ static inline void set_page_private_data(struct page *page, unsigned long data) > if (!PagePrivate(page)) { > get_page(page); > SetPagePrivate(page); > + set_page_private(page, 0); > } > set_bit(PAGE_PRIVATE_NOT_POINTER, &page_private(page)); > page_private(page) |= data << PAGE_PRIVATE_MAX; >