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Subject: Re: [PATCH 0/3] block: blk_interposer - Block Layer Interposer
To:     Hannes Reinecke <hare@suse.de>, Jens Axboe <axboe@kernel.dk>,
        Mike Snitzer <snitzer@redhat.com>,
        Sergei Shtepa <sergei.shtepa@veeam.com>, hch@lst.de
Cc:     "johannes.thumshirn@wdc.com" <johannes.thumshirn@wdc.com>,
        "koct9i@gmail.com" <koct9i@gmail.com>,
        "ming.lei@redhat.com" <ming.lei@redhat.com>,
        "josef@toxicpanda.com" <josef@toxicpanda.com>,
        "steve@sk2.org" <steve@sk2.org>,
        "linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Pavel Tide <Pavel.TIde@veeam.com>, dm-devel@redhat.com
References: <1607518911-30692-1-git-send-email-sergei.shtepa@veeam.com>
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 <208edf35-ecdc-2d73-4c48-0424943a78c0@suse.de>
From:   Bob Liu <bob.liu@oracle.com>
Message-ID: <cdc3c792-17ac-de61-12ae-74691769fc3c@oracle.com>
Date:   Tue, 15 Dec 2020 14:51:18 +0800
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Hi Folks,

On 12/12/20 12:56 AM, Hannes Reinecke wrote:
> On 12/11/20 5:33 PM, Jens Axboe wrote:
>> On 12/11/20 9:30 AM, Mike Snitzer wrote:
>>> While I still think there needs to be a proper _upstream_ consumer of
>>> blk_interposer as a condition of it going in.. I'll let others make the
>>> call.
>>
>> That's an unequivocal rule.
>>
>>> As such, I'll defer to Jens, Christoph and others on whether your
>>> minimalist blk_interposer hook is acceptable in the near-term.
>>
>> I don't think so, we don't do short term bandaids just to plan on
>> ripping that out when the real functionality is there. IMHO, the dm
>> approach is the way to go - it provides exactly the functionality that
>> is needed in an appropriate way, instead of hacking some "interposer"
>> into the core block layer.
>>
> Which is my plan, too.
> 
> I'll be working with the Veeam folks to present a joint patchset (including the DM bits) for the next round.
> 

Besides the dm approach, do you think Veeam's original requirement is a good
use case of "block/bpf: add eBPF based block layer IO filtering"?
https://lwn.net/ml/bpf/20200812163305.545447-1-leah.rumancik@gmail.com/

Thanks,
Bob