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Subject: Re: linux-next: manual merge of the block tree with the fscrypt tree
To:     Ming Lei <ming.lei@redhat.com>
Cc:     Stephen Rothwell <sfr@canb.auug.org.au>,
        Theodore Ts'o <tytso@mit.edu>,
        Linux Next Mailing List <linux-next@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Eric Biggers <ebiggers@google.com>
References: <20190116132522.1b756433@canb.auug.org.au>
 <ca843f39-3fcd-1a03-34c9-7284f10fe262@kernel.dk>
 <20190116031301.GC26146@ming.t460p>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <a1ce4d1d-13e0-c765-bf22-55fd67c9f1d4@kernel.dk>
Date:   Tue, 15 Jan 2019 20:17:36 -0700
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On 1/15/19 8:13 PM, Ming Lei wrote:
> On Tue, Jan 15, 2019 at 07:55:39PM -0700, Jens Axboe wrote:
>> On 1/15/19 7:25 PM, Stephen Rothwell wrote:
>>> Hi all,
>>>
>>> Today's linux-next merge of the block tree got a conflict in:
>>>
>>>   fs/ext4/readpage.c
>>>
>>> between commit:
>>>
>>>   acc9eb0a6073 ("ext4: add fs-verity read support")
>>>
>>> from the fscrypt tree and commit:
>>>
>>>   eb754eb2a953 ("block: allow bio_for_each_segment_all() to iterate over multi-page bvec")
>>>
>>> from the block tree.
>>>
>>> I fixed it up (see below - the former moved the code modified by the
>>> latter) and can carry the fix as necessary. This is now fixed as far as
>>> linux-next is concerned, but any non trivial conflicts should be mentioned
>>> to your upstream maintainer when your tree is submitted for merging.
>>> You may also want to consider cooperating with the maintainer of the
>>> conflicting tree to minimise any particularly complex conflicts.
>>
>> Ming, I'm pulling this, I thought we agreed none of these bullshit
>> renames? The fact that a patch looks like this:
>>
>> -               for_each_bvec(bv, (it)->bvecs, __cur_iter, __cur_iter)        \
>> +               for_each_segment(bv, (it)->bvecs, __cur_iter, __cur_iter)     \
>>
>> is SUPER annoying and does NOTHING but to cause merge conflicts.
>>
>> Resend it without that.
> 
> We need to differentiate 'segment' with 'bvec' in bvec helpers, which is
> usually seldom used by drivers. For example, only two in-tree users(ceph, iov_iter).
> That is why I rename it, and seems Christoph prefers to do it too.

If you want to do a rename, then we do it after. I don't want to deal with
weeks and weeks of fallout from this. Write a rename script that we can
then run at the end of the next merge window. You're going to be playing
catch-up until that happens if we go the current route, and honestly
I'm not at all interested in the fallout from that.

I know exactly what will happen until 5.1-rc opens, and what my tree will
look like from having to deal with this. And then I know exactly what Linus
is going to say, and I can't even argue against it, since he'll be totally
right.

Hence it's not going to happen this way.

-- 
Jens Axboe