linux-ext4 - Re: Regular ext4 error warning with HD in USB dock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20110108080520.GE12433@bitwizard.nl>
Date:	Sat, 8 Jan 2011 09:05:20 +0100
From:	Rogier Wolff <R.E.Wolff@...Wizard.nl>
To:	Amir Goldstein <amir73il@...il.com>
Cc:	Ted Ts'o <tytso@....edu>, Ric Wheeler <rwheeler@...hat.com>,
	Rogier Wolff <R.E.Wolff@...wizard.nl>,
	Con Kolivas <kernel@...ivas.org>, adilger.kernel@...ger.ca,
	linux-ext4@...r.kernel.org
Subject: Re: Regular ext4 error warning with HD in USB dock

On Fri, Jan 07, 2011 at 11:07:23PM +0200, Amir Goldstein wrote:
> On Fri, Jan 7, 2011 at 9:41 PM, Amir Goldstein <amir73il@...il.com> wrote:
> > On Fri, Jan 7, 2011 at 7:26 AM, Ted Ts'o <tytso@....edu> wrote:
> >> Am I missing something?  The kernel stores up to 3k worth of data, on
> >> a 4k block file system.  Whereas e2fsck patch blindly assume 2k worhth
> >> of data regardless of the block size.  The kernel patch looks ok, but
> >> the e2fsprogs patch seems badly broken....
> 
> So it's not badly broken, it copies blocksize-2K, which is clumsily
> written like this:
> +	int len = ctx->fs->blocksize - 2*SUPERBLOCK_OFFSET;

So this should be: 

  int len = ctx->fs->blocksize - SUPERBLOCK_OFFSET - sizeof (<superblock>);

Although those two numbers are equal right now, there is no reason to
assume that they will remain so in the future. So if the superblock
size (or the offset) changes in the future, it's much better to have
programmed this so that it will keep on working as opposed to getting
to deal with ugly bugs in code that hasn't changed in years...

	Roger. 
-- 
** R.E.Wolff@...Wizard.nl ** http://www.BitWizard.nl/ ** +31-15-2600998 **
**    Delftechpark 26 2628 XH  Delft, The Netherlands. KVK: 27239233    **
*-- BitWizard writes Linux device drivers for any device you may have! --*
Q: It doesn't work. A: Look buddy, doesn't work is an ambiguous statement. 
Does it sit on the couch all day? Is it unemployed? Please be specific! 
Define 'it' and what it isn't doing. --------- Adapted from lxrbot FAQ
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html