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Subject: Re: [PATCH] ext4: flag as supporting buffered async reads
From:   Jens Axboe <axboe@kernel.dk>
To:     "Theodore Y. Ts'o" <tytso@mit.edu>
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Date:   Mon, 24 Aug 2020 04:56:55 -0600
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On 8/22/20 9:48 AM, Jens Axboe wrote:
> On 8/22/20 8:33 AM, Theodore Y. Ts'o wrote:
>> On Fri, Aug 21, 2020 at 03:26:35PM -0600, Jens Axboe wrote:
>>>>>> Resending this one, as I've been carrying it privately since May. The
>>>>>> necessary bits are now upstream (and XFS/btrfs equiv changes as well),
>>>>>> please consider this one for 5.9. Thanks!
>>>>>
>>>>> The necessary commit only hit upstream as of 5.9-rc1, unless I'm
>>>>> missing something?  It's on my queue to send to Linus once I get my
>>>>> (late) ext4 primary pull request for 5.9.
>>>>
>>>> Right, it went in at the start of the merge window for 5.9. Thanks Ted!
>>>
>>> Didn't see it in the queue that just sent in, is it still queued up?
>>
>> It wasn't in the queue which I queued up because that was based on
>> 5.8-rc4.  Linus was a bit grumpy (fairly so) because it was late, and
>> that's totally on me.
>>
>> He has said that he's going to start ignoring pull requests that
>> aren't fixes only if this becomes a pattern, so while I can send him
>> another pull request which will just have that one change, there are
>> no guarantees he's going to take it at this late date.
>>
>> Sorry, when you sent me the commit saying that the changes that were
>> needed were already upstream on August 3rd, I thought that meant that
>> they were aready in Linus's tree.  I should have checked and noticed
>> that that in fact "ext4: flag as supporting buffered async reads"
>> wasn't compiling against Linus's upstream tree, so I didn't realize
>> this needed to be handled as a special case during the merge window.
> 
> Well to be honest, this kind of sucks. I've been posting it since May,
> and the ideal approach would have been to just ack it and I could have
> carried it in my tree. That's what we did for btrfs and XFS, both of
> which have it.
> 
> The required patches *were* upstreamed on August 3rd, which is why I
> mentioned that. But yes, not in 5.8 or earlier, of course.
> 
> So I suggest that you either include it for the next pull request for
> Linus, or that I put it in with your ack. Either is fine with me. I'd
> consider this a "dropping the ball" kind of thing, it's not like the
> patch hasn't been in linux-next or hasn't been ready for months. This
> isn't some "oh I wrote this feature after the merge window" event. It'd
> be a real shame to ship 5.9 and ext4 not have support for the more
> efficient async buffered reads, imho, especially since the two other
> major local file systems already have it.
> 
> Let me know what you think.

Ted, can you make a call on this, please? It's now post -rc2. Let's
get this settled and included, one way or another.


-- 
Jens Axboe