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Date:   Tue, 29 Mar 2022 09:52:07 -0600
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Subject: Re: state of drbd in mainline
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To:     Philipp Reisner <philipp.reisner@linbit.com>
Cc:     Christoph Hellwig <hch@lst.de>,
        Lars Ellenberg <lars.ellenberg@linbit.com>,
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From:   Jens Axboe <axboe@kernel.dk>
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On 3/29/22 9:44 AM, Philipp Reisner wrote:
> Jens, my intention is to keep it in-tree, and at some point update it.
> Regarding your questions:

That'd be great, but it's been years since there was any significant
updates to the in-kernel drbd... I would strongly suggest that the
in-kernel be brought closer to what people are mostly running, as it
stands it's basically unmaintained.

>> - Why aren't the drbd maintainers responding to posted patches? They seem
>>   to simply be ignored, and I'm left to pickup the trivial ones that look
>>   fine to me. In-kernel drbd appears largely unmaintained, and has been for
>>   years.
> 
> The team here has grown, we are busy. Since you started to pick up the
> trivial patches yourself, I thought it is not necessary that I collect
> them and send a pull request in merge-window time.

That's just one part of it, the fact that the out-of-tree drbd has been
drifting further and further away from the in-kernel one is a big
problem. For trivial patches, I have no issue picking them up. But
silence on your side is not very helpful. Please review and ack patches.
If I see it acked, then I can easily pick it up.

>> - Even if out-of-band communication is used for in-kernel users of drbd,
>>   that doesn't result in any patches or fixes that should go upstream?
> 
> This one:
> https://patchwork.kernel.org/project/linux-block/patch/20210426163032.3454129-1-christoph.boehmwalder@linbit.com/
> (relevant to users that have DRBD on top of md raid)

That's a single patch, from a year ago. Not a strong counter point,
looks more like it's proving my case...

>> - If there's zero activity for in-kernel drbd, all users are using the
>>   out-of-tree version?
> 
> There are users of the in-tree version, some with huge fleets.
> Some do not need the newer out-of-tree DRBD, and the in-tree version is a
> lot easier to compile. You need coccinelle for the out-of-tree version,
> and that can already be a hindering barrier for some.

The main discrepancy here is that there are apparently huge numbers of
in-tree users, yet no fixes or patches at all making it to mainline.
Either drbd is bug free and doesn't require any fixes at all, which I
very much would doubt, or fixes aren't being sent upstream.

-- 
Jens Axboe