[dm-devel] [PATCH 5/9] block: support diskcipher

[Jens Axboe]

On 8/21/19 12:42 AM, boojin.kim wrote:
> This patch supports crypto information to be maintained via BIO
> and passed to the storage driver.
> 
> To do this, 'bi_aux_private', 'REQ_CYPTE' and 'bi_dun' are added
> to the block layer.
> 
> 'bi_aux_private' is added for loading additional private information into
> BIO.
> 'REQ_CRYPT' is added to distinguish that bi_aux_private is being used
> for diskcipher.
> F2FS among encryption users uses DUN(device unit number) as
> the IV(initial vector) for cryptographic operations.
> DUN is stored in 'bi_dun' of bi_iter as a specific value for each BIO.
> 
> Before attempting to merge the two BIOs, the operation is also added to
> verify that the crypto information contained in two BIOs is consistent.

This isn't going to happen. With this, and the inline encryption
proposed by Google, we'll bloat the bio even more. At least the Google
approach didn't include bio iter changes as well.

Please work it out between yourselves so we can have a single, clean
abstraction that works for both.

-- 
Jens Axboe