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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 1128EC43381 for ; Mon, 4 Mar 2019 23:17:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DC4C820823 for ; Mon, 4 Mar 2019 23:17:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726150AbfCDXRS (ORCPT ); Mon, 4 Mar 2019 18:17:18 -0500 Received: from ipmail03.adl6.internode.on.net ([150.101.137.143]:52577 "EHLO ipmail03.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726069AbfCDXRS (ORCPT ); Mon, 4 Mar 2019 18:17:18 -0500 Received: from ppp59-167-129-252.static.internode.on.net (HELO dastard) ([59.167.129.252]) by ipmail03.adl6.internode.on.net with ESMTP; 05 Mar 2019 09:47:15 +1030 Received: from dave by dastard with local (Exim 4.80) (envelope-from ) id 1h0wpd-0006yw-RN; Tue, 05 Mar 2019 10:17:13 +1100 Date: Tue, 5 Mar 2019 10:17:13 +1100 From: Dave Chinner To: "Michael Kerrisk (man-pages)" Cc: Wang Shilong , "linux-fsdevel@vger.kernel.org" , Ext4 Developers List , xfs , linux-f2fs-devel@lists.sourceforge.net, lixi@ddn.com, Andreas Dilger , Wang Shilong , linux-man , "Darrick J. Wong" Subject: Re: [PATCH 2/2] statx.2: add project support update Message-ID: <20190304231713.GY23020@dastard> References: <1551449184-7942-1-git-send-email-wshilong1991@gmail.com> <1551449184-7942-3-git-send-email-wshilong1991@gmail.com> <20190304205006.GX23020@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Mon, Mar 04, 2019 at 10:16:29PM +0100, Michael Kerrisk (man-pages) wrote: > Hi Dave, > On Mon, 4 Mar 2019 at 21:50, Dave Chinner wrote: > > > > On Mon, Mar 04, 2019 at 02:52:59PM +0100, Michael Kerrisk (man-pages) wrote: > > > Hello Wang Shilong, > > > > > > On Fri, 1 Mar 2019 at 15:06, Wang Shilong wrote: > > > > > > > > From: Wang Shilong > > > > > > I take it that these patches relate to some API changes that are not > > > yet merged into the kernel, right? > > > > > > Also, I think we need some accompanying info to describe project IDs. > > > Can you point me at any documents/resources? > > > > Probably "best" documented in the man pages that ship with xfsprogs. > > But, these IDs are a kernel construct, right? On disk filesystem format construct, actually. The kernel doesn't use them for anything other than filesystem quota accounting - it's completely oblivious to the meaning of the IDs (unlike uids and gids used for user and group quota accounting). > Is their scope limited > just to XFS, or do other filesystems have the concept also? Originally only XFS. Irix implemented project quotas rather than group quotas, IIRC, in the late 80s/early 90s(*) so XFS supported project quotas for day zero. I think is was 2004/2005 that they were fully supported on Linux (using an exclusive group or project quota requirement) and with v5 filesystems we added a third quota inode so we can have user, group and project quotas all active on a filesystem at once. 2-3 years ago project quotas were added to ext4 and so anything that uses the generic kernel quota infrastructure can implement it, too. Cheers, Dave. (*) In some ways, we are still dragging Linux into the '80s, kicking and screaming all the way :P -- Dave Chinner david@fromorbit.com