From nobody Wed Feb 11 16:48:49 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2D32EC77B61 for ; Mon, 10 Apr 2023 09:39:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229696AbjDJJjZ (ORCPT ); Mon, 10 Apr 2023 05:39:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58254 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229740AbjDJJjX (ORCPT ); Mon, 10 Apr 2023 05:39:23 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F185D5279 for ; Mon, 10 Apr 2023 02:39:18 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8CDC761A32 for ; Mon, 10 Apr 2023 09:39:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AEE72C43443; Mon, 10 Apr 2023 09:39:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1681119558; bh=hQfvtLSuuwTvz2MLeajEI4NVGlDu7NNc7omUTcL4vyk=; h=From:To:Cc:Subject:Date:From; b=htSUCPpZOVsAJvoQg2qVAmzMdJCiKS4lo+6ZwcvoOlqUbWTB3wqpm/y06AIPYV2ji 3IgmKGtIStSoVph9kxLG19iJEhHEC9ZMoBgEAVRqaSDxN3vnn0UDam4DgfgR0mBzDZ okDsUILdt9SwNpZT5ruVuVZ1Btoxc5F0iV2xDC+2FJQdfe5Iid3Eh0Koj4nPDXhxk6 YBx67YCO3UFIh8rWwG0PYXxArMQNtFzkhfMYgjsQw7DfpsUTOcUiFu19YTcPP6eeC8 bYT9UeFc9r4bVkyUJ5WrFPHxAUl2diDZSf8oRFxtPuM79Xb4gLLurRGsp11N+wEMqR z0Il+vRNOftMg== From: Chao Yu To: jaegeuk@kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Chao Yu Subject: [PATCH RFC] f2fs: fix to use spinlock to avoid page.private update race Date: Mon, 10 Apr 2023 17:39:12 +0800 Message-Id: <20230410093912.2184557-1-chao@kernel.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" There may be subtle race condition, make PagePrivate and page_private being inconsistent, result in decreasing page count incorrectly, introduce a per-inode spinlock to avoid such condition. Signed-off-by: Chao Yu --- fs/f2fs/f2fs.h | 19 ++++++++++++++++++- fs/f2fs/super.c | 2 ++ 2 files changed, 20 insertions(+), 1 deletion(-) diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index c378aedcadea..6b31bef5853e 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -856,6 +856,8 @@ struct f2fs_inode_info { =20 unsigned int atomic_write_cnt; loff_t original_i_size; /* original i_size before atomic write */ + + spinlock_t private_lock; /* protect page->private */ }; =20 static inline void get_read_extent_info(struct extent_info *ext, @@ -1413,21 +1415,28 @@ static inline bool page_private_##name(struct page = *page) \ test_bit(PAGE_PRIVATE_##flagname, &page_private(page)); \ } =20 +static inline struct f2fs_inode_info *F2FS_I(struct inode *inode); #define PAGE_PRIVATE_SET_FUNC(name, flagname) \ static inline void set_page_private_##name(struct page *page) \ { \ + unsigned long flags; \ + spin_lock_irqsave(&F2FS_I(page->mapping->host)->private_lock, flags); \ if (!PagePrivate(page)) \ attach_page_private(page, (void *)page->private); \ set_bit(PAGE_PRIVATE_NOT_POINTER, &page_private(page)); \ set_bit(PAGE_PRIVATE_##flagname, &page_private(page)); \ + spin_unlock_irqrestore(&F2FS_I(page->mapping->host)->private_lock, flags)= ; \ } =20 #define PAGE_PRIVATE_CLEAR_FUNC(name, flagname) \ static inline void clear_page_private_##name(struct page *page) \ { \ + unsigned long flags; \ + spin_lock_irqsave(&F2FS_I(page->mapping->host)->private_lock, flags); \ clear_bit(PAGE_PRIVATE_##flagname, &page_private(page)); \ - if (page_private(page) =3D=3D BIT(PAGE_PRIVATE_NOT_POINTER)) \ + if (page_private(page) =3D=3D (BIT(PAGE_PRIVATE_NOT_POINTER))) \ detach_page_private(page); \ + spin_unlock_irqrestore(&F2FS_I(page->mapping->host)->private_lock, flags)= ; \ } =20 PAGE_PRIVATE_GET_FUNC(nonpointer, NOT_POINTER); @@ -1456,17 +1465,25 @@ static inline unsigned long get_page_private_data(s= truct page *page) =20 static inline void set_page_private_data(struct page *page, unsigned long = data) { + unsigned long flags; + + spin_lock_irqsave(&F2FS_I(page->mapping->host)->private_lock, flags); if (!PagePrivate(page)) attach_page_private(page, 0); set_bit(PAGE_PRIVATE_NOT_POINTER, &page_private(page)); page_private(page) |=3D data << PAGE_PRIVATE_MAX; + spin_unlock_irqrestore(&F2FS_I(page->mapping->host)->private_lock, flags); } =20 static inline void clear_page_private_data(struct page *page) { + unsigned long flags; + + spin_lock_irqsave(&F2FS_I(page->mapping->host)->private_lock, flags); page_private(page) &=3D GENMASK(PAGE_PRIVATE_MAX - 1, 0); if (page_private(page) =3D=3D BIT(PAGE_PRIVATE_NOT_POINTER)) detach_page_private(page); + spin_unlock_irqrestore(&F2FS_I(page->mapping->host)->private_lock, flags); } =20 /* For compression */ diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index a1b570a5e50f..555424dd85fd 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -1419,6 +1419,8 @@ static struct inode *f2fs_alloc_inode(struct super_bl= ock *sb) init_f2fs_rwsem(&fi->i_gc_rwsem[WRITE]); init_f2fs_rwsem(&fi->i_xattr_sem); =20 + spin_lock_init(&fi->private_lock); + /* Will be used by directory only */ fi->i_dir_level =3D F2FS_SB(sb)->dir_level; =20 --=20 2.25.1