From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1U3P16-0001R3-57 for mharc-grub-devel@gnu.org; Thu, 07 Feb 2013 05:47:44 -0500 Received: from eggs.gnu.org ([208.118.235.92]:46339) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U3P11-0001QK-Vq for grub-devel@gnu.org; Thu, 07 Feb 2013 05:47:42 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1U3P0z-0007OV-7A for grub-devel@gnu.org; Thu, 07 Feb 2013 05:47:39 -0500 Received: from dgate20.ts.fujitsu.com ([80.70.172.51]:10418) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U3P0y-0007NU-Sm for grub-devel@gnu.org; Thu, 07 Feb 2013 05:47:37 -0500 DomainKey-Signature: s=s1536a; d=ts.fujitsu.com; c=nofws; q=dns; h=X-SBRSScore:X-IronPort-AV:Received:X-IronPort-AV: Received:Message-ID:Date:From:Organization:User-Agent: MIME-Version:To:Subject:X-Enigmail-Version:Content-Type: Content-Transfer-Encoding; b=J5UoCYF0Sm423n5PnRTak4ve6hyQDsIRhZMXu2NTlblg7kOClfju81bd x3cY0xgstrFOOMTw1BPn70Q6RUxBm1A4cAr/eeIX3JwcMvBCe6U0c7fJr aOUARed+Gz1XKkwGsLLq01bC50eKA4/+0fF2zjs3uaXjxbXWOigZY4ZsL br6NGd47JfOsyWAmBla9LeZxdBuAGRh3tDxTG3hyAx8FV2OrWU/tilS0t DThLf0Dw8pHGMzapmvWC1ljSWFQGZ; DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=ts.fujitsu.com; i=@ts.fujitsu.com; q=dns/txt; s=s1536b; t=1360234056; x=1391770056; h=message-id:date:from:mime-version:to:subject: content-transfer-encoding; bh=2m6q4hzAnS57Hh0z0T1Yc3R/ca10Rh42DSRvzhda6Q4=; b=u9M2QLaMqMwVFQjgEvB4qTXFbs4cpnxEUq3o/F3cTUHYllj0VB9zl6TB lTo4lGb4538+uoJcijVhZiutyvMHtDW+K1wokfltZsNpJGgcNhpsVkNlw 88iJGnGDHI1IzYynvXtByCsNciKGUVp9hrXBUZhnD9MIGkdkFrb6waJqW wBB0OKSM3anXO+pZzqJI+NdZQXjAHRMTc37qCIgMbw4T/cfQ7WokDaXF8 VyAofTmSSqTXNpHS1UN+cQdkcsjYI; X-SBRSScore: None X-IronPort-AV: E=Sophos;i="4.84,621,1355094000"; d="scan'208";a="115364301" Received: from unknown (HELO abgdate50u.abg.fsc.net) ([172.25.138.66]) by dgate20u.abg.fsc.net with ESMTP; 07 Feb 2013 11:47:33 +0100 X-IronPort-AV: E=Sophos;i="4.84,621,1355094000"; d="scan'208";a="339482" Received: from unknown (HELO cooper.psw.pdbps.fsc.net) ([172.25.253.64]) by abgdate50u.abg.fsc.net with ESMTP; 07 Feb 2013 11:47:32 +0100 Message-ID: <51138645.4050405@ts.fujitsu.com> Date: Thu, 07 Feb 2013 11:47:33 +0100 From: Martin Wilck Organization: Fujitsu Technology Solutions User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: grub-devel@gnu.org Subject: GRUB and the risk of block list corruption in extX X-Enigmail-Version: 1.5.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 80.70.172.51 X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list Reply-To: The development of GNU GRUB List-Id: The development of GNU GRUB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 07 Feb 2013 10:47:43 -0000 Hello, this is a question about the long-running topic of installing GRUB in partitions or partitionless disks. Recently I have been involved in discussions about this on https://bugzilla.redhat.com/show_bug.cgi?id=872826. The Fedora boot loader can't be installed in partition headers any more. The major reason given by the Fedora developers is the famous GRUB warning "blocklists are UNRELIABLE and their use is discouraged." The Grub manual says "installing to a filesystem means that GRUB is vulnerable to its blocks being moved around by filesystem features such as tail packing, or even by aggressive fsck implementations". I'd like to understand how this blocklist corruption might come to pass (except for cases where "core.img" itself is moved, deleted, or overwritten by user space tools). Also, it has been recommended to prevent accidental corruption by setting the IMMUTABLE flag on core.img, and I'd like to ask for the GRUB experts' opinion about that. Finally I'd like to know if it's true that the GRUB team plans to drop block list support altogether in a future version. Regards Martin Wilck PS: It has been stated that of recent filesystems, this matters most for extX, because btrfs has a 64k header where embedding GRUB is usually possible. Therefore I asked a similar question on ext4-devel. -- Dr. Martin Wilck PRIMERGY System Software Engineer x86 Server Engineering FUJITSU Fujitsu Technology Solutions GmbH Heinz-Nixdorf-Ring 1 33106 Paderborn, Germany Phone: ++49 5251 525 2796 Fax: ++49 5251 525 2820 Email: martin.wilck@ts.fujitsu.com Internet: http://ts.fujitsu.com Company Details: http://ts.fujitsu.com/imprint