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Date:   Thu, 29 Aug 2019 07:41:04 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Matthew Bobrowski <mbobrowski@mbobrowski.org>
Cc:     Christoph Hellwig <hch@infradead.org>, Jan Kara <jack@suse.cz>,
        "Theodore Y. Ts'o" <tytso@mit.edu>,
        "Darrick J. Wong" <darrick.wong@oracle.com>,
        Ritesh Harjani <riteshh@linux.ibm.com>,
        adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, aneesh.kumar@linux.ibm.com
Subject: Re: [PATCH 0/5] ext4: direct IO via iomap infrastructure
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On Thu, Aug 29, 2019 at 09:20:50PM +1000, Matthew Bobrowski wrote:
> Uh ha! So, we conclude that there's no need to muck around with hairy
> ioend's, or the need to denote whether there's unwritten extents held
> against the inode using tricky state flag for that matter.

So in XFS we never had the i_unwritten counter, that is something
purely ext4 specific, and I can't really help with that unfortunately,
but maybe the people who implemented it might be able to help on that
one.