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Date: Wed, 5 Jun 2024 10:14:07 +0200
From: Christoph Hellwig <hch@lst.de>
To: Damien Le Moal <dlemoal@kernel.org>
Cc: Hannes Reinecke <hare@suse.de>, Christoph Hellwig <hch@lst.de>,
	Nitesh Shetty <nj.shetty@samsung.com>, Jens Axboe <axboe@kernel.dk>,
	Jonathan Corbet <corbet@lwn.net>, Alasdair Kergon <agk@redhat.com>,
	Mike Snitzer <snitzer@kernel.org>,
	Mikulas Patocka <mpatocka@redhat.com>,
	Keith Busch <kbusch@kernel.org>, Sagi Grimberg <sagi@grimberg.me>,
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	damien.lemoal@opensource.wdc.com, anuj20.g@samsung.com,
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	linux-doc@vger.kernel.org, dm-devel@lists.linux.dev,
	linux-nvme@lists.infradead.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v20 00/12] Implement copy offload support
Message-ID: <20240605081407.GA18688@lst.de>
References: <20240604043242.GC28886@lst.de> <393edf87-30c9-48b8-b703-4b8e514ac4d9@suse.de> <5441b256-494a-4344-89fd-ee8c5a073f8b@kernel.org>
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On Tue, Jun 04, 2024 at 04:39:25PM +0900, Damien Le Moal wrote:
> > But I wasn't aware that this approach is limited to copying within a 
> > single block devices; that would be quite pointless indeed.
> 
> Not pointless for any FS doing CoW+Rebalancing of block groups (e.g. btrfs) and
> of course GC for FSes on zoned devices. But for this use case, an API allowing
> multiple sources and one destination would be better.

Yes.