linux-kernel - Re: Back to the future.

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: <463AE623.60501@dgreaves.com>
Date:	Fri, 04 May 2007 08:52:03 +0100
From:	David Greaves <david@...eaves.com>
To:	Kyle Moffett <mrmacman_g4@....com>
Cc:	Pavel Machek <pavel@....cz>, nigel@...el.suspend2.net,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Pekka J Enberg <penberg@...helsinki.fi>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: Back to the future.

Kyle Moffett wrote:
> On May 03, 2007, at 11:10:47, Pavel Machek wrote:
>> How mature is freezing filesystems -- will it work on at least ext2/3
>> and vfat?
> 
> I'm pretty sure it works on ext2/3 and xfs and possibly others, I don't
> know either way about VFAT though.  Essentially the "freeze" part
> involves telling the filesystem to sync all data, flush the journal, and
> mark the filesystem clean.  The intent under dm/LVM was to allow you to
> make snapshots without having to fsck the just-created snapshot before
> you mounted it.
> 
>> What happens if you try to boot and filesystems are frozen from
>> previous run?
> 
> If you're just doing a fresh boot then the filesystem is already clean
> due to the dm freeze and so it mounts up normally.  All you need to do
> then is have a little startup script which purges the saved image before
> you fsck or remount things read-write since either case means the image
> is no longer safe to resume.

Wouldn't it be better if freeze wrote a freeze-ID to the fs and returned it?
This would naturally be kept in the image and a UUID mismatch would be
detectable - seems safer and more flexible than 'a script'.

"This isn't the freeze you're looking for, move along"

David
-
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/