Re: jbd2 inside a device mapper module

From: Andreas Dilger
Date: Sat Dec 27 2008 - 15:02:16 EST


On Dec 25, 2008 12:35 -0200, Alberto Bertogli wrote:
> On Wed, Dec 24, 2008 at 06:49:15PM -0500, Theodore Tso wrote:
> > I have no idea why you would need to do manual __breads(). No doubt
> > I'm missing some context here.
>
> I'm writing (just for fun and learning purposes) a device mapper module
> that stores checksums on writes and verifies them on reads. The
> integrity metadata (currently just the checksum) is interleaved in the
> backing device: one sector holding the integrity metadata for the
> following 64 data sectors.

Alex and I discussed implementing checksums for ext4 using an external
device like this, and he might have some more design information for
you.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.

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