Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932891Ab0HDOo6 (ORCPT ); Wed, 4 Aug 2010 10:44:58 -0400 Received: from mail-fx0-f46.google.com ([209.85.161.46]:51316 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932591Ab0HDOo4 convert rfc822-to-8bit (ORCPT ); Wed, 4 Aug 2010 10:44:56 -0400 MIME-Version: 1.0 In-Reply-To: References: <1280887483-2979-2-git-send-email-wad@chromium.org> <20100804090049.GH5464@nb.net.home> Date: Wed, 4 Aug 2010 09:44:55 -0500 Message-ID: Subject: Re: [PATCH v2 2/3] genhd, efi: add efi partition metadata to hd_structs From: Will Drewry To: Kay Sievers , Tejun Heo Cc: Karel Zak , linux-kernel@vger.kernel.org, Jens Axboe , "David S. Miller" , Andrew Morton , Joe Perches , Jan Blunck , Greg Kroah-Hartman Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2248 Lines: 48 On Wed, Aug 4, 2010 at 5:14 AM, Kay Sievers wrote: > On Wed, Aug 4, 2010 at 11:00, Karel Zak wrote: >> On Tue, Aug 03, 2010 at 09:04:42PM -0500, Will Drewry wrote: >>> This change extends the partition_meta_info structure to >>> support EFI GPT-specific metadata and ensures that data >>> is copied in on partition scanning. >> >> Why do want to store GPT-specific data (efi_guid_t) to >> partition_meta_info? I think it would be better to use label and uuid >> in a generic format (e.g. string or u8 uuid[16]) -- then you don't >> have to use things like union, disklabel specific code to compare >> uuids, etc. ?IMHO your current code is too complicated. > > I don't mind having the raw data and the type accessible. It might be > useful for something we don't know about and it basically comes for > free. I'll bump out the uuid at least, but it might be worth keeping an extended meta info option. But it's a lot less work to ditch it, so I'm happy enough either way. > But the only thing we are really interested in is the UUID, which, > like Tejun already suggested, we should probably store > format-independent, and have it always accessible. That way, we would > not need any type-specific parser, we just handle the normal DCE > format. I'll bump it out and make it the efi code generic-ify its uuid. Out of curiousity, were you and Tejun thinking of keeping it as a 36 byte string or as the 16 byte packed value. While less space efficient, I'd prefer the u8[36] as it avoids dealing with versioning when parsing the user-supplied string. Instead, each partition type can properly unparse its uuids according to what they expect. Seem reasonable? > I don't think we should support any of the labels anyway in root= and > similar, because they never really worked reliably with duplicates, > and just ask for trouble. Agreed. I don't think labels make sense, but we may later want to support partition types (as I mention in my other mail). -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/