From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1U7Srk-0005Vf-PJ for mharc-grub-devel@gnu.org; Mon, 18 Feb 2013 10:42:52 -0500 Received: from eggs.gnu.org ([208.118.235.92]:57497) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U7Srf-0005UM-Ry for grub-devel@gnu.org; Mon, 18 Feb 2013 10:42:50 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1U7SrW-0002Yd-1C for grub-devel@gnu.org; Mon, 18 Feb 2013 10:42:47 -0500 Received: from dgate10.ts.fujitsu.com ([80.70.172.49]:2099) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U7SrV-0002XU-Lw for grub-devel@gnu.org; Mon, 18 Feb 2013 10:42:37 -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:References:In-Reply-To: X-Enigmail-Version:Content-Type:Content-Transfer-Encoding; b=iQzD9/+xfi/JZaEtuatNzhynIxN4cBfYTF1BOhPt1j+9uMMceakwbcbu qfvVJ3xmOKdsVXEtcmIZ+fosEQnE0W52rYzGvzHENiEE3tCJggj8HE87u G1DfSzWtkVMj4hvNCcRjGgtYsgD8r9d6EguF4YUDlVBA0hcQgDUW4eE0w 7VGmAHaT05FXgilGjVxuBxtAgMKkK+g2foFlUQSuu5mTgelXktsHCvyb5 R39AkVqLLD12oPYOaLE95UhVeX498; DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=ts.fujitsu.com; i=@ts.fujitsu.com; q=dns/txt; s=s1536b; t=1361202157; x=1392738157; h=message-id:date:from:mime-version:to:subject:references: in-reply-to:content-transfer-encoding; bh=4EWgXUXJhX05qPhZClQwbIdBujUexxrWSkEQVfcQoCU=; b=juNkCY8j3abALj9Nr1SG11kfxxpZ7ndsaJdLYEOpJREyBZsStbUjwlOj Qbq/VOxxsbTPxG5mEPsmJNFhus/48ckcwiIKze1QxM1t0zZF7FdXY/5k1 Q9G5zStneqHm+dTmgL5fZmYxybA8/km3DfKLstmHp2gnJWO/Gm2whPNTJ SlT8gjVfFj1f7opQAlOjD1auv8JbByMtgbj5KcPmR/TkX9Fq71j32k1qI qBE5feXHdJ9gjUOETWiq7T6RpRN/Q; X-SBRSScore: None X-IronPort-AV: E=Sophos;i="4.84,688,1355094000"; d="scan'208";a="137270803" Received: from unknown (HELO abgdgate60u.abg.fsc.net) ([172.25.138.90]) by dgate10u.abg.fsc.net with ESMTP; 18 Feb 2013 16:42:34 +0100 X-IronPort-AV: E=Sophos;i="4.84,688,1355094000"; d="scan'208";a="54937413" Received: from unknown (HELO cooper.psw.pdbps.fsc.net) ([172.25.253.64]) by abgdgate60u.abg.fsc.net with ESMTP; 18 Feb 2013 16:42:34 +0100 Message-ID: <51224BE9.2020707@ts.fujitsu.com> Date: Mon, 18 Feb 2013 16:42:33 +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: Re: GRUB and the risk of block list corruption in extX References: <51138645.4050405@ts.fujitsu.com> <51153345.2020509@ts.fujitsu.com> <20130208184239.GA20462@csclub.uwaterloo.ca> In-Reply-To: <20130208184239.GA20462@csclub.uwaterloo.ca> 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: 80.70.172.49 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: Mon, 18 Feb 2013 15:42:51 -0000 On 02/08/2013 07:42 PM, Lennart Sorensen wrote: > Of course the block list breaks if the file in the filesystem is modified > or moved without updating the block list, which used to break lilo all the > time whenever one forgot to run the lilo command after making a change. True. lilo accessed the conf file itself via block list, IIRC. The conf file is typically changed often. GRUB's "core.img", on the contrary, tends to be pretty static. Moreover, it's usually created using grub2-install, which runs grub-setup anyway after core.img is rewritten (thus recreating the block list if necessary). > Sure grub 0.9x was a bit less fragile than lilo, but block lists for > files that could potentially be changed is fragile. "files that could potentially be changed" is important here. As long as "core.img" itself isn't touched, the risk of the block list being corrupted is very small; at least that's what the ext4 developers said on the parallel thread on ext4-devel. The risk can be further reduced with "chattr +i core.img". Grub 0.9x' stage1_5_* files are 100% static, and thus practically safe. > Embedding enough of grub in the first track or a boot partition (as EFI > systems support, as do a number of non x86 architectures) gives a much > more reliable system since it can read anything else it needs using the > filesystem and hence doesn't break if files are changed. I understand that, but sometimes it's just not enough. Martin -- 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