[dm-devel] Re: jbd2 inside a device mapper module

[Andreas Dilger <adilger sun com>]

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.