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Date: Fri, 20 Aug 2021 06:11:58 +0200
From: Christoph Hellwig <hch@lst.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: Christoph Hellwig <hch@lst.de>, "Darrick J. Wong" <djwong@kernel.org>,
	Matthew Wilcox <willy@infradead.org>,
	Andreas Gruenbacher <agruenba@redhat.com>,
	Shiyang Ruan <ruansy.fnst@fujitsu.com>,
	linux-xfs <linux-xfs@vger.kernel.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	linux-btrfs <linux-btrfs@vger.kernel.org>,
	Linux NVDIMM <nvdimm@lists.linux.dev>, cluster-devel@redhat.com
Subject: Re: [PATCH 11/30] iomap: add the new iomap_iter model
Message-ID: <20210820041158.GA26417@lst.de>
References: <20210809061244.1196573-1-hch@lst.de> <20210809061244.1196573-12-hch@lst.de> <CAPcyv4hbSYnOC6Pdi1QShRxGjBAteig7nN1h-5cEvsFDX9SuAQ@mail.gmail.com>
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On Thu, Aug 19, 2021 at 02:25:52PM -0700, Dan Williams wrote:
> Given most of the iomap_iter users don't care about srcmap, i.e. are
> not COW cases, they are leaving srcmap zero initialized. Should the
> IOMAP types be incremented by one so that there is no IOMAP_HOLE
> confusion? In other words, fold something like this?

A hole really means nothing to read from the source.  The existing code
also relies on that.