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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 96583CA9EAF for ; Thu, 24 Oct 2019 10:03:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 70644205F4 for ; Thu, 24 Oct 2019 10:03:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393147AbfJXKDZ (ORCPT ); Thu, 24 Oct 2019 06:03:25 -0400 Received: from mail.cn.fujitsu.com ([183.91.158.132]:39078 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725874AbfJXKDZ (ORCPT ); Thu, 24 Oct 2019 06:03:25 -0400 X-IronPort-AV: E=Sophos;i="5.68,224,1569254400"; d="scan'208";a="77414985" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 24 Oct 2019 18:03:23 +0800 Received: from G08CNEXCHPEKD02.g08.fujitsu.local (unknown [10.167.33.83]) by cn.fujitsu.com (Postfix) with ESMTP id 06C994CE1510; Thu, 24 Oct 2019 17:55:30 +0800 (CST) Received: from [10.167.220.84] (10.167.220.84) by G08CNEXCHPEKD02.g08.fujitsu.local (10.167.33.89) with Microsoft SMTP Server id 14.3.439.0; Thu, 24 Oct 2019 18:03:24 +0800 Subject: Re: [PATCH] quotactl.2: Add some details about Q_QUOTAON To: Jan Kara CC: , References: <1571904693-22537-1-git-send-email-xuyang2018.jy@cn.fujitsu.com> <20191024095558.GL31271@quack2.suse.cz> From: Yang Xu Message-ID: Date: Thu, 24 Oct 2019 18:03:22 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.0 MIME-Version: 1.0 In-Reply-To: <20191024095558.GL31271@quack2.suse.cz> Content-Type: text/plain; charset="gbk"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.167.220.84] X-yoursite-MailScanner-ID: 06C994CE1510.AE8D6 X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: xuyang2018.jy@cn.fujitsu.com Sender: linux-man-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-man@vger.kernel.org on 2019/10/24 17:55, Jan Kara wrote: > On Thu 24-10-19 16:11:33, Yang Xu wrote: >> For Q_QUOTAON, on old kernel we can use quotacheck -ug to >> generate quota files. But in current kernel, we can also hide them >> in system inodes and indicate them by using "quota" or project feature. >> >> For user or group quota, we can do as below(etc ext4): >> mkfs.ext4 -F -o quota /dev/sda5 >> mount /dev/sda5 /mnt >> quotactl(QCMD(Q_QUOTAON, USRQUOTA), /dev/sda5, QFMT_VFS_V0, NULL); >> >> For project quota, we can do as below(etc ext4) >> mkfs.ext4 -F -o quota,project /dev/sda5 >> mount /dev/sda5 /mnt >> quotactl(QCMD(Q_QUOTAON, PRJQUOTA), /dev/sda5, QFMT_VFS_V0, NULL); >> >> Signed-off-by: Yang Xu > > ... >> The quota file must exist; it is normally created with the >> .BR quotacheck (8) >> -program. >> +program. It also can been stored as hidden system inode. In this case, there >> +are no visible quota files in filesystem and no need to use >> +.BR quotacheck (8) >> +program. This is indicated by 'quota' and 'project' features. >> This operation requires privilege >> .RB ( CAP_SYS_ADMIN ). >> .TP 8 > > This is a good clarification. Thanks! I'd just somewhat expand this like: > > Quota information can be also stored in hidden system inodes for ext4, xfs, > and other filesystems if the filesystem is configured so. In this case, > there are no visible quota files and there is no need to use quotacheck(8). > Quota information is always kept consistent by the filesystem and Q_QUOTAON > quotactl only enables enforcement of quota limits. The presence of hidden > system inodes with quota information is indicated by DQF_SYS_FILE flag in > Q_GETINFO output. Good. It is very professional. > >> @@ -638,7 +641,8 @@ The >> .I id >> argument is ignored. >> .TP >> -.B Q_XQUOTARM >> +.B Q_XQUOTARM (Since linux 3.16) >> +.\" 9da93f9b7cdf8ab28da6b364cdc1fafc8670b4dc > > Not sure if we need to specify commit ID here... It is only a supplementary explanation. Other flag has similar id message such as Q_XGETNEXTQUOTA in quotactl.2 ------ .BR Q_XGETNEXTQUOTA " (since Linux 4.6)" .\" commit 8b37524962b9c54423374717786198f5c0820a28 ------ So, I think it is no problem. > > Honza >