2.6.1 CryptoAPI woes

[Johannes Graumann <graumann@caltech.edu>]

Hello,

I set out to create an encrypted partition using my new 2.6.1 custom
kernel (compiled from kernel.org sources, loopdevice and cryptoloop
statically compiled in, ciphers present as modules). Following what was
said in several HOWTOs, I said 'modprobe aes' and tried various
permutations of 'losetup -e aes-256 /dev/loop0 /dev/hda4' - with the
result that I went nearly mad running into 'ioctl: LOOP_SET_STATUS:
Invalid argument' after entering the password. After several hours I was
about to accept defeat, when I used 'losetup -e aes /dev/loop0
/dev/hda4' - and behold: it works!
Now: how do I make sure this is AES-256 and not some other permutation
of the cypher?

And on another note: in
http://www.mirrors.wiretapped.net/security/cryptography/filesystems/loop-aes/loop-AES.README
I read the following: 
"Don't use a journaling file system on top of file backed loop device,
unless underlying file system is journaled and guarantees data=ordered
or data=journal."
Can anybody comment on whether I can use reiserfs on top of my loopback?

Thanks for any hints,

Joh