From nobody Wed Feb 11 22:54:26 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8E1FE6139 for ; Wed, 19 Jun 2024 07:00:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718780450; cv=none; b=M9m2FhHSgsdNJEUsBXtPHJ4mKb0+qlJKOEMWwNUT6NLLfd4AUJXpvnFjIx2S/WvUvVX7pr6m2QJPzCxO6cQofr/1h+ZinGfcekXylUFk9LpOxoyrlLSHl6VGbKQ04rNjp9zMKDkExK/5hvvkUSYuR/KSHhS19qpg9cShjG+rjhg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718780450; c=relaxed/simple; bh=wPbUog/DATDmQJOPIEg/tT8i2uUOLhSWvxoc0kvyq7k=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=KLoEzp6e9zd2NAsg25XDJEGc5eUqjS9FTEboitsGOshB0niE5TEY6IJe/VGvqMS1+N0QixbZi9ZJUCpwBm0HLyA18XJaaRUXxGYR5wnuO7XJ3HIM9l/zFBibIolpE0fz9PW0sggVUDuhF/YDkTnkTP6vKkckX+l5NT+CD+D5wXQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=saljTd/s; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="saljTd/s" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0FF6AC2BBFC; Wed, 19 Jun 2024 07:00:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1718780450; bh=wPbUog/DATDmQJOPIEg/tT8i2uUOLhSWvxoc0kvyq7k=; h=From:To:Cc:Subject:Date:From; b=saljTd/sUGkjW86DOOXAHaPKZb2M/Fo4U8E8YKkYZ15LJFZfX6xHollfquVXYZfnd UPpp3vDvdfwxpmcunISjHVffIs5BcCNmql22gpAYx8J00cUkec4xnM84/yV8lzhvQ8 dZEItioKmeow+3aGOpiUwlYLunsTu/VWnouiTp5vtSkwCabxoI0wYC/b0i18AybJkR C4BMK8nw9HCzesx5/SDtlwH6Uemax2LzIDS4I5e7P8JYtMWxcuKz+6JdwXGh0wPZWY wTuuyMosQVDvVnV8k1dq80yUk/1K30fNSOfILNsFI6Ctdaco2l3xjExl02Pf/WW3Kx 3jn0hS3K5N5tQ== From: Chao Yu To: jaegeuk@kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Chao Yu , Daeho Jeong Subject: [PATCH] f2fs: atomic: fix to avoid racing w/ GC Date: Wed, 19 Jun 2024 15:00:42 +0800 Message-Id: <20240619070042.1197204-1-chao@kernel.org> X-Mailer: git-send-email 2.40.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Case #1: SQLite App GC Thread Kworker Shrinker - f2fs_ioc_start_atomic_write - f2fs_ioc_commit_atomic_write - f2fs_commit_atomic_write - filemap_write_and_wait_range : write atomic_file's data to cow_inode echo 3 > drop_caches to drop atomic_file's cache. - f2fs_gc - gc_data_segment - move_data_page - set_page_dirty - writepages - f2fs_do_write_data_page : overwrite atomic_file's data to cow_inode - f2fs_down_write(&fi->i_gc_rwsem[WRITE]) - __f2fs_commit_atomic_write - f2fs_up_write(&fi->i_gc_rwsem[WRITE]) Case #2: SQLite App GC Thread Kworker - f2fs_ioc_start_atomic_write - __writeback_single_inode - do_writepages - f2fs_write_cache_pages - f2fs_write_single_data_page - f2fs_do_write_data_page : write atomic_file's data to cow_inode - f2fs_gc - gc_data_segment - move_data_page - set_page_dirty - writepages - f2fs_do_write_data_page : overwrite atomic_file's data to cow_inode - f2fs_ioc_commit_atomic_write In above cases racing in between atomic_write and GC, previous data in atomic_file may be overwrited to cow_file, result in data corruption. This patch introduces PAGE_PRIVATE_ATOMIC_WRITE bit flag in page.private, and use it to indicate that there is last dirty data in atomic file, and the data should be writebacked into cow_file, if the flag is not tagged in page, we should never write data across files. Fixes: 3db1de0e582c ("f2fs: change the current atomic write way") Cc: Daeho Jeong Signed-off-by: Chao Yu --- fs/f2fs/data.c | 10 +++++++++- fs/f2fs/f2fs.h | 8 +++++++- 2 files changed, 16 insertions(+), 2 deletions(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 0b4f563f2361..22031b9b507c 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -2647,10 +2647,13 @@ int f2fs_do_write_data_page(struct f2fs_io_info *fi= o) struct dnode_of_data dn; struct node_info ni; bool ipu_force =3D false; + bool atomic_commit; int err =3D 0; =20 /* Use COW inode to make dnode_of_data for atomic write */ - if (f2fs_is_atomic_file(inode)) + atomic_commit =3D f2fs_is_atomic_file(inode) && + page_private_atomic(fio->page); + if (atomic_commit) set_new_dnode(&dn, F2FS_I(inode)->cow_inode, NULL, NULL, 0); else set_new_dnode(&dn, inode, NULL, NULL, 0); @@ -2749,6 +2752,8 @@ int f2fs_do_write_data_page(struct f2fs_io_info *fio) f2fs_outplace_write_data(&dn, fio); trace_f2fs_do_write_data_page(page_folio(page), OPU); set_inode_flag(inode, FI_APPEND_WRITE); + if (atomic_commit) + clear_page_private_atomic(page); out_writepage: f2fs_put_dnode(&dn); out: @@ -3718,6 +3723,9 @@ static int f2fs_write_end(struct file *file, =20 set_page_dirty(page); =20 + if (f2fs_is_atomic_file(inode)) + set_page_private_atomic(page); + if (pos + copied > i_size_read(inode) && !f2fs_verity_in_progress(inode)) { f2fs_i_size_write(inode, pos + copied); diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 777497919c62..35dd2d45b0ed 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -1413,7 +1413,8 @@ static inline void f2fs_clear_bit(unsigned int nr, ch= ar *addr); * bit 1 PAGE_PRIVATE_ONGOING_MIGRATION * bit 2 PAGE_PRIVATE_INLINE_INODE * bit 3 PAGE_PRIVATE_REF_RESOURCE - * bit 4- f2fs private data + * bit 4 PAGE_PRIVATE_ATOMIC_WRITE + * bit 5- f2fs private data * * Layout B: lowest bit should be 0 * page.private is a wrapped pointer. @@ -1423,6 +1424,7 @@ enum { PAGE_PRIVATE_ONGOING_MIGRATION, /* data page which is on-going migrating= */ PAGE_PRIVATE_INLINE_INODE, /* inode page contains inline data */ PAGE_PRIVATE_REF_RESOURCE, /* dirty page has referenced resources */ + PAGE_PRIVATE_ATOMIC_WRITE, /* data page from atomic write path */ PAGE_PRIVATE_MAX }; =20 @@ -2401,14 +2403,17 @@ static inline void clear_page_private_##name(struct= page *page) \ PAGE_PRIVATE_GET_FUNC(nonpointer, NOT_POINTER); PAGE_PRIVATE_GET_FUNC(inline, INLINE_INODE); PAGE_PRIVATE_GET_FUNC(gcing, ONGOING_MIGRATION); +PAGE_PRIVATE_GET_FUNC(atomic, ATOMIC_WRITE); =20 PAGE_PRIVATE_SET_FUNC(reference, REF_RESOURCE); PAGE_PRIVATE_SET_FUNC(inline, INLINE_INODE); PAGE_PRIVATE_SET_FUNC(gcing, ONGOING_MIGRATION); +PAGE_PRIVATE_SET_FUNC(atomic, ATOMIC_WRITE); =20 PAGE_PRIVATE_CLEAR_FUNC(reference, REF_RESOURCE); PAGE_PRIVATE_CLEAR_FUNC(inline, INLINE_INODE); PAGE_PRIVATE_CLEAR_FUNC(gcing, ONGOING_MIGRATION); +PAGE_PRIVATE_CLEAR_FUNC(atomic, ATOMIC_WRITE); =20 static inline unsigned long get_page_private_data(struct page *page) { @@ -2440,6 +2445,7 @@ static inline void clear_page_private_all(struct page= *page) clear_page_private_reference(page); clear_page_private_gcing(page); clear_page_private_inline(page); + clear_page_private_atomic(page); =20 f2fs_bug_on(F2FS_P_SB(page), page_private(page)); } --=20 2.40.1