From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755507AbYIAPCN (ORCPT ); Mon, 1 Sep 2008 11:02:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754767AbYIAPBv (ORCPT ); Mon, 1 Sep 2008 11:01:51 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:49678 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754531AbYIAPBu (ORCPT ); Mon, 1 Sep 2008 11:01:50 -0400 Date: Mon, 1 Sep 2008 11:01:47 -0400 From: Christoph Hellwig To: David Woodhouse Cc: Artem Bityutskiy , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Adrian Hunter Subject: Re: [PATCH] UBIFS: fill f_fsid Message-ID: <20080901150147.GA20323@infradead.org> References: <1220194366-12731-1-git-send-email-dedekind@infradead.org> <1220194366-12731-13-git-send-email-dedekind@infradead.org> <1220262187.2982.58.camel@pmac.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1220262187.2982.58.camel@pmac.infradead.org> User-Agent: Mutt/1.5.18 (2008-05-17) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 01, 2008 at 10:43:07AM +0100, David Woodhouse wrote: > On Sun, 2008-08-31 at 17:52 +0300, Artem Bityutskiy wrote: > > From: Artem Bityutskiy > > > > UBIFS stores 16-bit UUID in the superblock, and it is a good > > idea to return part of it in 'f_fsid' filed of kstatfs structure. > > I think you mean a 16-byte UUID, not 16-bit? > > > + memcpy(&buf->f_fsid, c->uuid, sizeof(__kernel_fsid_t)); > > For btrfs I xor the first 64 bits with the second 64 bits, and put > _that_ into f_fsid. You're just putting the first 64 bits in and > ignoring the second 64 bits. Neither is really _better_ than the other; > you just alter the circumstances in which you get collisions. But I > suppose we might as well be consistent about how we do it? XFS just puts in the st_dev. And I can't realy find any useful defintion of what it's supposed to b anyway..