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Date: Tue, 22 Oct 2024 16:40:00 +0200
From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, Keith Busch <kbusch@meta.com>,
	linux-block@vger.kernel.org, linux-nvme@lists.infradead.org,
	axboe@kernel.dk, io-uring@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, joshi.k@samsung.com,
	javier.gonz@samsung.com, Nitesh Shetty <nj.shetty@samsung.com>,
	Hannes Reinecke <hare@suse.de>
Subject: Re: [PATCHv8 1/6] block, fs: restore kiocb based write hint
 processing
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References: <20241017160937.2283225-1-kbusch@meta.com> <20241017160937.2283225-2-kbusch@meta.com> <20241018055032.GB20262@lst.de> <ZxZ3o_HzN8HN6QPK@kbusch-mbp> <20241022064309.GA11161@lst.de> <Zxe4xL-sM5yF2isM@kbusch-mbp>
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On Tue, Oct 22, 2024 at 08:37:56AM -0600, Keith Busch wrote:
> No doubt it's almost certainly not a good idea to mix different stream
> usages, but that's not the kernels problem. It's user space policy. I
> don't think the kernel needs to perform any heroic efforts to split
> anything here. Just keep it simple.

Unfortunately it's not.  This complicated breaks any intelligent
scheme to manage them.  You can't write portable code assuming you
can know write streams when you need to cope with someone else using
some or all of the same resources.