From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 16BA3C43603 for ; Wed, 18 Dec 2019 11:19:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DE2F4206E0 for ; Wed, 18 Dec 2019 11:19:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726825AbfLRLTl (ORCPT ); Wed, 18 Dec 2019 06:19:41 -0500 Received: from mx2.suse.de ([195.135.220.15]:58044 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726682AbfLRLTl (ORCPT ); Wed, 18 Dec 2019 06:19:41 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id A381DB1B5; Wed, 18 Dec 2019 11:19:39 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 9A65D1E0B2D; Wed, 18 Dec 2019 12:12:13 +0100 (CET) From: Jan Kara To: Ted Tso Cc: , Paul Richards , Jan Kara Subject: [PATCH] ext4: Clarify impact of 'commit' mount option Date: Wed, 18 Dec 2019 12:12:10 +0100 Message-Id: <20191218111210.14161-1-jack@suse.cz> X-Mailer: git-send-email 2.16.4 Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org The description of 'commit' mount option dates back to ext3 times. Update the description to match current meaning for ext4. Reported-by: Paul Richards Signed-off-by: Jan Kara --- Documentation/admin-guide/ext4.rst | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/Documentation/admin-guide/ext4.rst b/Documentation/admin-guide/ext4.rst index 059ddcbe769d..8d292f5aaea3 100644 --- a/Documentation/admin-guide/ext4.rst +++ b/Documentation/admin-guide/ext4.rst @@ -181,14 +181,17 @@ When mounting an ext4 filesystem, the following option are accepted: system after its metadata has been committed to the journal. commit=nrsec (*) - Ext4 can be told to sync all its data and metadata every 'nrsec' - seconds. The default value is 5 seconds. This means that if you lose - your power, you will lose as much as the latest 5 seconds of work (your - filesystem will not be damaged though, thanks to the journaling). This - default value (or any low value) will hurt performance, but it's good - for data-safety. Setting it to 0 will have the same effect as leaving - it at the default (5 seconds). Setting it to very large values will - improve performance. + This setting limits the maximum age of the running transaction to + 'nrsec' seconds. The default value is 5 seconds. This means that if + you lose your power, you will lose as much as the latest 5 seconds of + metadata changes (your filesystem will not be damaged though, thanks + to the journaling). This default value (or any low value) will hurt + performance, but it's good for data-safety. Setting it to 0 will have + the same effect as leaving it at the default (5 seconds). Setting it + to very large values will improve performance. Note that due to + delayed allocation even older data can be lost on power failure since + writeback of those data begins only after time set in + /proc/sys/vm/dirty_expire_centisecs. barrier=<0|1(*)>, barrier(*), nobarrier This enables/disables the use of write barriers in the jbd code. -- 2.16.4