From nobody Sat Feb 7 15:15:22 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 14AD6EB64DC for ; Sun, 25 Jun 2023 11:54:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231249AbjFYLyd (ORCPT ); Sun, 25 Jun 2023 07:54:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42786 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230058AbjFYLya (ORCPT ); Sun, 25 Jun 2023 07:54:30 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BE57A11A for ; Sun, 25 Jun 2023 04:54:28 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3822060BA9 for ; Sun, 25 Jun 2023 11:54:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 63C0AC433C0; Sun, 25 Jun 2023 11:54:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1687694067; bh=Ch2PkuYne+BSGDeUtDNlSfgVPijfci/1QU9ugIlHiwo=; h=From:To:Cc:Subject:Date:From; b=q/v3pa3mroDWQGJkh02iAz3tPzW5pMe9WmniobjxiBl05R5WtG5Zq2gXQyEwLGLL+ hCqkTxHbQGaXgK+9Maie/MdYZc8xXNst9q7e0hu4rQPOYax1zurkF6mEL/dH4H/eio MvSO/5xnjcVKN4UyaJjVijNkqM9BFUQbVnOrau15GjO4x6rfqjzNC710dFD30BtFso ABwBQxZ+ouhScvvirtdTriMlOPXEXZiT9Qd2PjWC/2KuaCM0Mqh0ezfghs4NASqFVv 2m6eud7tzJbAKpslrccERQKa6BxYY1ZjtWvtzpGDhYRoTVdYFkvzM3eIau2DSp+C/O DDTAgL8aurnQQ== From: Chao Yu To: jaegeuk@kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Chao Yu Subject: [PATCH v2] f2fs: fix to avoid mmap vs set_compress_option case Date: Sun, 25 Jun 2023 19:54:20 +0800 Message-Id: <20230625115420.3138459-1-chao@kernel.org> X-Mailer: git-send-email 2.40.1 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" Compression option in inode should not be changed after they have been used, however, it may happen in below race case: Thread A Thread B - f2fs_ioc_set_compress_option - check f2fs_is_mmap_file() - check get_dirty_pages() - check F2FS_HAS_BLOCKS() - f2fs_file_mmap - set_inode_flag(FI_MMAP_FILE) - fault - do_page_mkwrite - f2fs_vm_page_mkwrite - f2fs_get_block_locked - fault_dirty_shared_page - set_page_dirty - update i_compress_algorithm - update i_log_cluster_size - update i_cluster_size Avoid such race condition by covering f2fs_file_mmap() w/ i_sem lock, meanwhile add mmap file check condition in f2fs_may_compress() as well. Fixes: e1e8debec656 ("f2fs: add F2FS_IOC_SET_COMPRESS_OPTION ioctl") Signed-off-by: Chao Yu --- v2: - fix potential deadlock. fs/f2fs/f2fs.h | 3 ++- fs/f2fs/file.c | 23 ++++++++++++++++++----- 2 files changed, 20 insertions(+), 6 deletions(-) diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 68759922d081..7b9af2d51656 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -4483,7 +4483,8 @@ static inline bool f2fs_low_mem_mode(struct f2fs_sb_i= nfo *sbi) static inline bool f2fs_may_compress(struct inode *inode) { if (IS_SWAPFILE(inode) || f2fs_is_pinned_file(inode) || - f2fs_is_atomic_file(inode) || f2fs_has_inline_data(inode)) + f2fs_is_atomic_file(inode) || f2fs_has_inline_data(inode) || + f2fs_is_mmap_file(inode)) return false; return S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode); } diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 4d22d2c5ab4b..9d760c26adb0 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -528,7 +528,11 @@ static int f2fs_file_mmap(struct file *file, struct vm= _area_struct *vma) =20 file_accessed(file); vma->vm_ops =3D &f2fs_file_vm_ops; + + f2fs_down_read(&F2FS_I(inode)->i_sem); set_inode_flag(inode, FI_MMAP_FILE); + f2fs_up_read(&F2FS_I(inode)->i_sem); + return 0; } =20 @@ -1926,12 +1930,19 @@ static int f2fs_setflags_common(struct inode *inode= , u32 iflags, u32 mask) int err =3D f2fs_convert_inline_inode(inode); if (err) return err; - if (!f2fs_may_compress(inode)) - return -EINVAL; - if (S_ISREG(inode->i_mode) && F2FS_HAS_BLOCKS(inode)) + + f2fs_down_write(&F2FS_I(inode)->i_sem); + if (!f2fs_may_compress(inode) || + (S_ISREG(inode->i_mode) && + F2FS_HAS_BLOCKS(inode))) { + f2fs_up_write(&F2FS_I(inode)->i_sem); return -EINVAL; - if (set_compress_context(inode)) - return -EOPNOTSUPP; + } + err =3D set_compress_context(inode); + f2fs_up_write(&F2FS_I(inode)->i_sem); + + if (err) + return err; } } =20 @@ -3970,6 +3981,7 @@ static int f2fs_ioc_set_compress_option(struct file *= filp, unsigned long arg) file_start_write(filp); inode_lock(inode); =20 + f2fs_down_write(&F2FS_I(inode)->i_sem); if (f2fs_is_mmap_file(inode) || get_dirty_pages(inode)) { ret =3D -EBUSY; goto out; @@ -3989,6 +4001,7 @@ static int f2fs_ioc_set_compress_option(struct file *= filp, unsigned long arg) f2fs_warn(sbi, "compression algorithm is successfully set, " "but current kernel doesn't support this algorithm."); out: + f2fs_up_write(&F2FS_I(inode)->i_sem); inode_unlock(inode); file_end_write(filp); =20 --=20 2.40.1