Re: [PATCH v5 00/11] blksnap - block devices snapshots module

Eric Biggers
2023-06-12T16:19:25Z

On Mon, Jun 12, 2023 at 03:52:17PM +0200, Sergei Shtepa wrote:
> Hi all.
>
> I am happy to offer a improved version of the Block Devices Snapshots
> Module. It allows to create non-persistent snapshots of any block devices.
> The main purpose of such snapshots is to provide backups of block devices.
> See more in Documentation/block/blksnap.rst.

How does blksnap interact with blk-crypto?

I.e., what happens if a bio with a ->bi_crypt_context set is submitted to a
block device that has blksnap active?

If you are unfamiliar with blk-crypto, please read
Documentation/block/inline-encryption.rst

It looks like blksnap hooks into the block layer directly, via the new
"blkfilter" mechanism. I'm concerned that it might ignore ->bi_crypt_context
and write data to the disk in plaintext, when it is supposed to be encrypted.

- Eric