Subject: Re: Journaling for FFS
To: Jochen Kunz <jkunz@unixag-kl.fh-kl.de>
From: Jason Thorpe <thorpej@shagadelic.org>
List: tech-kern
Date: 10/02/2006 15:11:05
On Oct 2, 2006, at 2:53 PM, Jochen Kunz wrote:
> On Mon, 2 Oct 2006 13:45:07 -0700
> Jason Thorpe <thorpej@shagadelic.org> wrote:
>
>> Doing journaling as a mount option is not as feasible as it sounds.
>> You actually need to record "journal enabled" in the superblock
>> because it changes how recovery is performed.
> Sure. I should have written: Ability to switch jornaling on or off
> without affecting data stored on the file system. (Maybe via tunefs
> (8).)
This is where it all gets exciting :-)
So, tunefs would need:
1- Journal reply (for "turn journal off").
2- A way to allocate space for the journal in the file system
(presumably contiguous space, this this avoids having to do bmap to
write to the journal) (for "turn journal on").
-- thorpej