[dm-devel] dm-verity: Verification fails but do not see Input/Output Error on read

[Mikulas Patocka]

On Wed, 28 Aug 2013, Chaitra Bhat wrote:

> Hi Mikulas,
> 
> Thanks for your e-mail. Yes, there was an error in the script which I 
> have fixed now.
> 
> Also, on further analysis found that the behaviour that I was seeing was 
> probably due to the dd command. When I read the verity device in 
> multiple of block-size after having corrupted the underlying verity 
> device, I always got I/O error. But if I tried to read back the specific 
> error location, I did not get an I/O error.

If you can reproduce the misbehavior, send a script that does it.

> Another odd behaviour - Create the verity target, corrupt the underlying 
> device, remove the mapping and establish the mapping again. Then read 
> the specific corrupted location through dd (not even block size), always 
> get an I/O error. Seems like some kind of caching being done when the 
> verity device is mapped - very odd.
> 
> Regards,
> Chaitra

Mikulas