From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752649AbdG1TOm (ORCPT ); Fri, 28 Jul 2017 15:14:42 -0400 Received: from mail.kernel.org ([198.145.29.99]:56336 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752385AbdG1TOk (ORCPT ); Fri, 28 Jul 2017 15:14:40 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1946E22B6E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=jaegeuk@kernel.org From: Jaegeuk Kim To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Cc: Jaegeuk Kim Subject: [PATCH] f2fs: don't need to wait for node writes for atomic write Date: Fri, 28 Jul 2017 12:14:38 -0700 Message-Id: <20170728191438.34330-1-jaegeuk@kernel.org> X-Mailer: git-send-email 2.13.0.rc1.294.g07d810a77f-goog Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We have a node chain to serialize node block writes, so if any IOs for node block writes are reordered, we'll get broken node chain. IOWs, roll-forward recovery will see all or none node blocks given fsync mark. E.g., Node chain consists of: N1 -> N2 -> N3 -> NFSYNC -> N1' -> N2' -> N'FSYNC Reordered to: 1) N1 -> N2 -> N3 -> N2' -> NFSYNC -> N'FSYNC -> power-cut 2) N1 -> N2 -> N3 -> N1' -> NFSYNC -> power-cut 3) N1 -> N2 -> NFSYNC -> N1' -> N'FSYNC -> N3 -> power-cut 4) N1 -> NFSYNC -> N1' -> N2' -> N'FSYNC -> N3 -> power-cut Roll-forward recovery can proceed to: 1) N1 -> N2 -> N3 -> NFSYNC -> X 2) N1 -> N2 -> N3 -> NFSYNC -> N1' -> X 3) N1 -> N2 -> N3 -> FSYNC -> N1' -> X 4) N1 -> X Signed-off-by: Jaegeuk Kim --- fs/f2fs/file.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index a0413c951458..0246d19d96c3 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -274,9 +274,19 @@ static int f2fs_do_sync_file(struct file *file, loff_t start, loff_t end, goto sync_nodes; } - ret = wait_on_node_pages_writeback(sbi, ino); - if (ret) - goto out; + /* + * If it's atomic_write, it's just fine to keep write ordering. So + * here we don't need to wait for node write completion, since we use + * node chain which serializes node blocks. If one of node writes are + * reordered, we can see simply broken chain, resulting in stopping + * roll-forward recovery. It means we'll recover all or none node blocks + * given fsync mark. + */ + if (!atomic) { + ret = wait_on_node_pages_writeback(sbi, ino); + if (ret) + goto out; + } /* once recovery info is written, don't need to tack this */ remove_ino_entry(sbi, ino, APPEND_INO); -- 2.13.0.rc1.294.g07d810a77f-goog