Re: state of drbd in mainline

From: Jens Axboe <axboe@kernel.dk>
To: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Christoph Hellwig <hch@lst.de>,
	Lars Ellenberg <lars.ellenberg@linbit.com>,
	drbd-dev@lists.linbit.com, linux-block@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: state of drbd in mainline
Date: Wed, 30 Mar 2022 12:24:46 -0600	[thread overview]
Message-ID: <0dc208a9-22f2-6758-e776-752ff81e2b19@kernel.dk> (raw)
In-Reply-To: <CADGDV=WcTSSC70yG61dazo-WyoLOzp3r+nOk-Eg2x_Ncx=3nRg@mail.gmail.com>

On 3/30/22 9:23 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.
> 
> The changes we worked on over many Years in the more recent drbd-9.x
> branches are just too fundamental to do them in small chunks, we could
> upstream bit by bit.  We need to get that reviewed in a big series.  If I

Your development model is fundamentally broken. You've allowed your 9.x
branch to totally drift from mainline, which just helps underline my
earlier point on that in-kernel drbd is effectively abandoned and
unmaintained.

> started to dump them on linux-block right away, nobody would look at it
> seriously, since it would be too much.  I intend to get people from red
> hat/suse assigned to do such a review. Then we will do that on linux-block,
> so that everyone who cares sees what happens.

You're just doing it totally wrong. Upstream kernel should match your
9.x branch, and it should have been developed in sync. What you appear
to have done is to ignore mainline, while it would've been correct and
much easier in the long run to ensure that development is regularly
synced to the mainline kernel. You know, like EVERY other driver that is
maintained does.

Now you've got a giant pile of patches, which probably don't adhere to
how we would've done the mainline commits in the first place, and it'll
cause a huge pain for not just you but upstream reviewers. I don't care
about the former, but I do care a lot about the latter. That's a giant
waste of the time of the folks involved on the block side, and
definitely not what a responsible kernel maintainer would do.

From your reply here and earlier ones, seems to me that you don't grasp
the gravity of the situation, which is also worrying.

>> 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.
> 
> It is the broad consent among the users of the drbd-8.4 branch (that is what
> is in-tree), is that it works for its purpose. It is for sure not bug-free,
> but people are not running into bugs anymore. So, call it free of relevant
> bugs, if you want.  No new features go into that branch, on purpose. To keep
> it that way.
> 
> Have a look at that one real bug-fix that was identified in the last Year.
> https://patchwork.kernel.org/project/linux-block/patch/20210426163032.3454129-1-christoph.boehmwalder@linbit.com/
> 
> When do you want to have that reposted to you?
> right now? Just before the next merge window opens?

That can go in anytime, so please do submit it.

-- 
Jens Axboe