From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 B670938AC99; Sat, 17 Oct 2026 16:20:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792254028; cv=none; b=HSk90eew8ut1gt5yu386Sk6RwGxwl0L+u3NEdOIvhZzWHiOa2FX6vdQihpQF+GJM8LfQxkqVTKkazK77aXFC1a8Lu1pMSqYp2BqIfR03Vqzj/kwS1jnP7wl8vGH9OW+lPq50Mb/jXXojVI5NKP7DflP0IzKQ2DC6f+iw8gknlPI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792254028; c=relaxed/simple; bh=gAbHcoEVKbnsurPTfYBNKHBTfcc0OuammNq4TXlSyio=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=M/R6C7P50wIfnhbnz6Q3v6x9psqmFb4BYcDd+3F6YdmC15rcskpxlONHCH6wR3/Dkj29llqc1d1jpJtLAgcEnPgx64UfFa8OjbLn8vqJu6KncLqNgsLniX59i50QRV2x5fWOkMUl+XTbUXFCZgRjKX2Z6khfw9O7vh2fQ4Eq26I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=o0Ay5mYS; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="o0Ay5mYS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 199761F000C4; Sat, 17 Oct 2026 16:20:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792254027; bh=hNeZPhdA5W6CBVT1NGlNz89lJ35uV5eteUhs9e3AuuY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=o0Ay5mYSNx4Ykr8FXjsXf3AmMUQEirgZnfvFA9htpb4RpLpc/JNQBpnZJpkLbLU3E U+2Nn3uE9Fuu+YqApdIo/PaNI/38qhGa3MzRhvyyy2ksebZ7RZZS4NY2b5sUcLbIs5 OrAWAME9W2HGWAQ8uZQIOmPdeU+SeYlBMWZYWL/w= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yongpeng Yang , Chao Yu , Jaegeuk Kim , Sasha Levin Subject: [PATCH 6.12 312/869] f2fs: fix data loss caused by incorrect use of nat_entry flag Date: Sat, 17 Oct 2026 17:52:33 +0200 Message-ID: <20261017160045.075459119@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160036.979869304@linuxfoundation.org> References: <20261017160036.979869304@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yongpeng Yang [ Upstream commit 238e14eb7226f883b72caccd2d37bf5707df066b ] Data loss can occur when fsync is performed on a newly created file (before any checkpoint has been written) concurrently with a checkpoint operation. The scenario is as follows: create & write & fsync 'file A' write checkpoint - f2fs_do_sync_file // inline inode - f2fs_write_inode // inode folio is dirty - f2fs_write_checkpoint - f2fs_flush_merged_writes - f2fs_sync_node_pages - f2fs_flush_nat_entries - f2fs_fsync_node_pages // no dirty node - f2fs_need_inode_block_update // return false SPO and lost 'file A' f2fs_flush_nat_entries() sets the IS_CHECKPOINTED and HAS_LAST_FSYNC flags for the nat_entry, but this does not mean that the checkpoint has actually completed successfully. However, f2fs_need_inode_block_update() checks these flags and incorrectly assumes that the checkpoint has finished. The root cause is that the semantics of IS_CHECKPOINTED and HAS_LAST_FSYNC are only guaranteed after the checkpoint write fully completes. This patch modifies f2fs_need_inode_block_update() to acquire the sbi->node_write lock before reading the nat_entry flags, ensuring that once IS_CHECKPOINTED and HAS_LAST_FSYNC are observed to be set, the checkpoint operation has already completed. Fixes: e05df3b115e7 ("f2fs: add node operations") Signed-off-by: Yongpeng Yang Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Sasha Levin --- fs/f2fs/node.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index 9709a212e6a03..56d5fb77569d7 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -419,6 +419,7 @@ bool f2fs_need_inode_block_update(struct f2fs_sb_info *sbi, nid_t ino) struct nat_entry *e; bool need_update = true; + f2fs_down_read(&sbi->node_write); f2fs_down_read(&nm_i->nat_tree_lock); e = __lookup_nat_cache(nm_i, ino); if (e && get_nat_flag(e, HAS_LAST_FSYNC) && @@ -426,6 +427,7 @@ bool f2fs_need_inode_block_update(struct f2fs_sb_info *sbi, nid_t ino) get_nat_flag(e, HAS_FSYNCED_INODE))) need_update = false; f2fs_up_read(&nm_i->nat_tree_lock); + f2fs_up_read(&sbi->node_write); return need_update; } -- 2.53.0