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Date:   Mon, 12 Jun 2023 09:19:11 -0700
From:   Eric Biggers <ebiggers@kernel.org>
To:     Sergei Shtepa <sergei.shtepa@veeam.com>
Cc:     axboe@kernel.dk, hch@infradead.org, corbet@lwn.net,
        snitzer@kernel.org, viro@zeniv.linux.org.uk, brauner@kernel.org,
        dchinner@redhat.com, willy@infradead.org, dlemoal@kernel.org,
        linux@weissschuh.net, jack@suse.cz, ming.lei@redhat.com,
        linux-block@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v5 00/11] blksnap - block devices snapshots module
Message-ID: <20230612161911.GA1200@sol.localdomain>
References: <20230612135228.10702-1-sergei.shtepa@veeam.com>
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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