From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754217Ab1JTLGA (ORCPT ); Thu, 20 Oct 2011 07:06:00 -0400 Received: from e4.ny.us.ibm.com ([32.97.182.144]:53856 "EHLO e4.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750947Ab1JTLF6 (ORCPT ); Thu, 20 Oct 2011 07:05:58 -0400 From: "Aneesh Kumar K.V" To: Christoph Hellwig , "J. Bruce Fields" Cc: agruen@kernel.org, akpm@linux-foundation.org, viro@zeniv.linux.org.uk, dhowells@redhat.com, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH -V7 21/26] richacl: xattr mapping functions In-Reply-To: <20111020091946.GA23773@infradead.org> References: <1318951981-5508-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <1318951981-5508-22-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <20111019222021.GB1874@fieldses.org> <87k4805alx.fsf@linux.vnet.ibm.com> <20111020091434.GC5444@fieldses.org> <20111020091946.GA23773@infradead.org> User-Agent: Notmuch/0.9_rc1-42-g76fdca8 (http://notmuchmail.org) Emacs/23.3.1 (x86_64-pc-linux-gnu) Date: Thu, 20 Oct 2011 16:32:04 +0530 Message-ID: <87aa8w53kj.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii x-cbid: 11102011-3534-0000-0000-000000C7324F Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 20 Oct 2011 05:19:46 -0400, Christoph Hellwig wrote: > On Thu, Oct 20, 2011 at 05:14:34AM -0400, J. Bruce Fields wrote: > > > > Does it really make sense to use a string here just to pick between the > > > > three choices OWNER@, GROUP@, and EVERYONE@? Why not just another small > > > > integer? Is the goal to expand this somehow eventually? > > > > > > > I guess Andreas wanted the disk layout to be able to store user@domain > > > format if needed. > > > > Is that likely? For that to be useful, tasks would need to be able to > > run as user@domain strings. And we'd probably want owners and groups to > > also be user@domain strings. > > > > The container people seem to eventually want to add some kind of > > namespace identifier everywhere: > > > > http://marc.info/?l=linux-kernel&m=131836778427871&w=2 > > > > in which case I guess we'd likely end up with (uid, user namespace id) > > instead of user@domain? > > > Storing strings is an extremly stupid idea. The only thing that would > make sense would be storing a windows-style 128-bit GUID. > How about updating the richacl_xattr as below struct richace_xattr { __le16 e_type; __le16 e_flags; __le32 e_mask; __le32 e_size; u8 e_id[0]; }; now e_flags can contain ACE4_SPECIAL_WHO to indicate value in e_id indicate special who values (which could be 1 byte value indicating OWNER@, GROUP@ or EVERYONE@), ACE4_UNIXID_WHO, to indicate value in e_id is the little endian value of unix id. ACE_WINSID_WHO to indicate e_id is the 128 bit array containing SID value. ? -aneesh