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Date:   Mon, 10 Apr 2023 23:25:02 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Donald Buczek <buczek@molgen.mpg.de>
Cc:     Sergei Shtepa <sergei.shtepa@veeam.com>, axboe@kernel.dk,
        hch@infradead.org, corbet@lwn.net, snitzer@kernel.org,
        viro@zeniv.linux.org.uk, brauner@kernel.org, willy@infradead.org,
        kch@nvidia.com, martin.petersen@oracle.com, vkoul@kernel.org,
        ming.lei@redhat.com, gregkh@linuxfoundation.org,
        linux-block@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v3 02/11] block: Block Device Filtering Mechanism
Message-ID: <ZDT9PjLeQgjVA16P@infradead.org>
References: <20230404140835.25166-1-sergei.shtepa@veeam.com>
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 <793db44e-9e6d-d118-3f88-cdbffc9ad018@molgen.mpg.de>
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On Sat, Apr 08, 2023 at 05:30:19PM +0200, Donald Buczek wrote:
> Maybe detach the old filter and attach the new one instead? An atomic replace might be usefull and it wouldn't complicate the code to do that instead. If its the same filter, maybe just return success and don't go through ops->detach and ops->attach?

I don't think a replace makes any sense.  We might want multiple
filters eventually, but unless we have a good use case for even just
more than a single driver we can deal with that once needed.  The
interface is prepared to support multiple attached filters already.