linux-kernel - Re: [Patch] document ext3 requirements (was Re: [RFD] Incremental fsck)

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: <20080118142308.GD12796@mit.edu>
Date:	Fri, 18 Jan 2008 09:23:08 -0500
From:	Theodore Tso <tytso@....EDU>
To:	Bryan Henderson <hbryan@...ibm.com>
Cc:	Ric Wheeler <ric@....com>, Al Boldi <a1426z@...ab.com>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	David Chinner <dgc@....com>, linux-kernel@...r.kernel.org,
	Pavel Machek <pavel@....cz>,
	Daniel Phillips <phillips@...gle.com>,
	Rik van Riel <riel@...hat.com>,
	Valerie Henson <val.henson@...il.com>
Subject: Re: [Patch] document ext3 requirements (was Re: [RFD] Incremental
	fsck)

On Thu, Jan 17, 2008 at 04:31:48PM -0800, Bryan Henderson wrote:
> But I heard some years ago from a disk drive engineer that that is a myth 
> just like the rotational energy thing.  I added that to the discussion, 
> but admitted that I haven't actually seen a disk drive write a partial 
> sector.

Well, it would be impossible or at least very hard to see that in
practice, right?  My understanding is that drives do sector-level
checksums, so if there was a partially written sector, the checksum
would be bogus and the drive would return an error when you tried to
read from it.

> Ted brought up the separate issue of the host sending garbage to the disk 
> device because its own power is failing at the same time, which makes the 
> integrity at the disk level moot (or even undesirable, as you'd rather 
> write a bad sector than a good one with the wrong data).

Yep, exactly.  It would be interesting to see if this happens on
modern hardware; all of the evidence I've had for this is years old at
this point.  

							- Ted
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/