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Date: Sun, 19 Oct 2003 22:01:05 +0200
From: Pavel Machek <pavel@suse.cz>
To: William Lee Irwin III <wli@holomorphy.com>,
       Hans Reiser <reiser@namesys.com>, Larry McVoy <lm@bitmover.com>,
       Norman Diamond <ndiamond@wta.att.ne.jp>,
       Wes Janzen <superchkn@sbcglobal.net>,
       Rogier Wolff <R.E.Wolff@BitWizard.nl>,
       John Bradford <john@grabjohn.com>, linux-kernel@vger.kernel.org,
       nikita@namesys.com, Pavel Machek <pavel@ucw.cz>,
       Justin Cormack <justin@street-vision.com>,
       Russell King <rmk+lkml@arm.linux.org.uk>,
       Vitaly Fertman <vitaly@namesys.com>, Krzysztof Halasa <khc@pm.waw.pl>,
       axboe@suse.de
Subject: Re: Blockbusting news, results are in
Message-ID: <20031019200105.GD354@elf.ucw.cz>
References: <1c6401c395e7$16630d00$3eee4ca5@DIAMONDLX60> <20031019041553.GA25372@work.bitmover.com> <3F924660.4040405@namesys.com> <20031019083551.GA1108@holomorphy.com>
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Hi!

> >> I've told you guys over and over that you need to CRC the data in user
> >> space, we do that in our backup scripts and it tells us when the drives
> >> are going bad.  S
> 
> On Sun, Oct 19, 2003 at 12:08:00PM +0400, Hans Reiser wrote:
> > Why do the CRC in user space, that requires modifying every one of 7000+ 
> > applications (if I understand you correctly, which is far from a sure 
> > thing;-) )?
> > Write a reiser4 CRC file plugin.  It would take a weekend, and most of the 
> > work would be cut and pasting from the default file plugin..  
> > I understand why you do it in BK, but for user space as a whole user space 
> > is the wrong place.
> 
> I think the fs driver layer might be the wrong thing too; maybe it'd be
> best to do the CRC and/or checksumming at the block layer?

I think that's best place.

Here's first attempt at implementation:
http://www.ussg.iu.edu/hypermail/linux/kernel/0004.3/0487.html

									Pavel
-- 
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]