From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1U7fiU-0007GJ-Kd for mharc-grub-devel@gnu.org; Tue, 19 Feb 2013 00:26:10 -0500 Received: from eggs.gnu.org ([208.118.235.92]:43297) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U7fiR-0007G7-TI for grub-devel@gnu.org; Tue, 19 Feb 2013 00:26:08 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1U7fiP-0001pZ-Lz for grub-devel@gnu.org; Tue, 19 Feb 2013 00:26:07 -0500 Received: from mail-lb0-f178.google.com ([209.85.217.178]:64027) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1U7fiP-0001pT-EP for grub-devel@gnu.org; Tue, 19 Feb 2013 00:26:05 -0500 Received: by mail-lb0-f178.google.com with SMTP id n1so4855457lba.9 for ; Mon, 18 Feb 2013 21:26:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:x-received:in-reply-to:references:date:message-id :subject:from:to:content-type; bh=ae8AYPR9VoQi3G/y9rChtsOLGfK12ckeqZE66XkvvbE=; b=iYqqHAdpd/33iCYBKLOoPj6ZDZCfqJUOhAChSLMjIAJxZpTfYN34NFS46wesY0JWWW BdshBb6e74bfTx7fyWp0f+h+99nuYha8ks0eWxcYksVLiP2VA9exFbRWAR1wAdcu18CS 5NDSXp0/E3DY1sUMGmaCMGdTvaVpytVUcGrhFf7DLjjWRRzyrdkaFQJI2KYHah6/YhUd VNn0FFefmY3MGq+s0tWSPrS3cU/N63vzh9/thnqptv8SFe+3Ie13GrDaAXILnooThj/q Y/X1JfzPZHx7aX8NFIB3s0e4z/elJjjNOgLUfGRueDK5GUotJSaSs0Ig75dWpgdOGIs7 sEbw== MIME-Version: 1.0 X-Received: by 10.152.109.112 with SMTP id hr16mr13017531lab.38.1361251564305; Mon, 18 Feb 2013 21:26:04 -0800 (PST) Received: by 10.112.43.230 with HTTP; Mon, 18 Feb 2013 21:26:04 -0800 (PST) In-Reply-To: <51138645.4050405@ts.fujitsu.com> References: <51138645.4050405@ts.fujitsu.com> Date: Tue, 19 Feb 2013 09:26:04 +0400 Message-ID: Subject: Re: GRUB and the risk of block list corruption in extX From: Andrey Borzenkov To: The development of GNU GRUB Content-Type: text/plain; charset=ISO-8859-1 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 209.85.217.178 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: Tue, 19 Feb 2013 05:26:09 -0000 On Thu, Feb 7, 2013 at 2:47 PM, Martin Wilck wrote: > Hello, > Hi Martin > 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. > I think this is simply the wrong question for upstream. The primary consideration is, what happens inside filesystem is outside of grub scope, so grub simply cannot commit itself to saying "it's fine and we support it everywhere". Because grub has no control over what happens. If you are sure in your environment corruption cannot happen (e.g. because you use filesystem that is known to be not susceptible to such corruption) then by all means do it. grub2 does not stop you from doing it. It just wants you to do it consciously :)