From owner-freebsd-current@FreeBSD.ORG Sun Aug 8 12:57:41 2010 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 9B0691065674; Sun, 8 Aug 2010 12:57:41 +0000 (UTC) (envelope-from marius@nuenneri.ch) Received: from mail-qy0-f175.google.com (mail-qy0-f175.google.com [209.85.216.175]) by mx1.freebsd.org (Postfix) with ESMTP id 08F148FC0A; Sun, 8 Aug 2010 12:57:40 +0000 (UTC) Received: by qyk11 with SMTP id 11so1352686qyk.13 for ; Sun, 08 Aug 2010 05:57:40 -0700 (PDT) Received: by 10.224.69.17 with SMTP id x17mr7580311qai.283.1281272260167; Sun, 08 Aug 2010 05:57:40 -0700 (PDT) MIME-Version: 1.0 Received: by 10.229.219.17 with HTTP; Sun, 8 Aug 2010 05:57:20 -0700 (PDT) In-Reply-To: References: <20100808103055.GA2037@garage.freebsd.pl> From: =?UTF-8?Q?Marius_N=C3=BCnnerich?= Date: Sun, 8 Aug 2010 14:57:20 +0200 Message-ID: To: Ivan Voras Content-Type: text/plain; charset=UTF-8 Cc: freebsd-hackers@freebsd.org, freebsd-current@freebsd.org, freebsd-geom@freebsd.org Subject: Re: glabel "force sectorsize" patch X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 08 Aug 2010 12:57:41 -0000 On Sun, Aug 8, 2010 at 14:02, Ivan Voras wrote: > On 8.8.2010 12:30, Pawel Jakub Dawidek wrote: >> On Sun, Aug 08, 2010 at 03:57:44AM +0200, Ivan Voras wrote: >>> Hi, >>> >>> In order to help users having 4k sector drives which the system >>> recognizes as 512 byte sector drives, I'm proposing a patch to glabel >>> which enables it to use a forced sector size for its native-labeled >>> providers. It is naturally only usable with glabel-native labels >>> (those created by "glabel label") and not partition and file system >>> labels because we cannot add arbitrary new fields to metadata of those >>> types. >>> >>> The patch is here: >>> >>> http://people.freebsd.org/~ivoras/diffs/glabel_ssize.patch >> [...] >>> This mechanism is a band-aid until there's a better way of dealing >>> with 4k drives. >> >> So why do you want to obfuscate glabel with it? For people to start >> depend on it? Once we start supporting 4kB sectors what do we do with >> such a change? Remove it and decrease version number? What people will >> do with providers already labeled this way? >> >> If its temporary, just allow to list providers you want to increase >> sector size in /boot/loader.conf. Once we start supporting it properly >> people might simply remove it from loader.conf and it should just work. >> >> Glabel is not for that and I don't agree for such obfuscation. > > Of course, there are good and bad sides to it. My take on it is that the > only bad side is that it really isn't glabel's primary function to > (optionally) fixup geometry, while the good sides are: > > * glabel is in GENERIC and judging by the mailing lists' traffic it is > one of the better used parts of the system so people are familiar with > it. It is also already used as a perfectly valid fixup for device > renaming, making both UFS and ZFS more stable for usage. > > * You can't really "make people depend on glabel" both because it is in > GENERIC and because of it storing metadata in the last sector, making > the rest of the drive completely usable without it in the event native > 4k sector support is grown. > > I'd like to hear comments from the wider audience. In respect with your > comment, I will compromise: as 4k sector drives have become available > over the counter more than 6 months ago and so far I think this is the > first effort to give some support for them, I will commit this patch > before 9.0 code freeze only if no other support gets developed. I do not like this at all. Even if it's just for the KISS and POLA principles. A geom should do one thing and do it right imo. Why not write a new geom class that does what you want?