On Mon, Dec 29, 2008 at 11:50:14AM +0530, Shyam_Iyer@xxxxxxxx wrote: > Andreas Dilger wrote: > > 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. > > > That external device could possibly be a TPM chip that can store > checksums. Thanks for the suggestion. The code I have at the moment (without the journal stuff) already has the capability of storing checksums in a different device. It's one of the reasons why I would prefer to avoid using jbd. I think I'll go with the "two metadatas" approach and see how it goes. Worst case scenario is that I have to drop that code, which means to be back where I am now, only with one less option. Thanks, Alberto -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
