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Date:   Tue, 30 May 2023 16:20:10 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Johannes Thumshirn <Johannes.Thumshirn@wdc.com>
Cc:     Christoph Hellwig <hch@lst.de>, Chris Mason <clm@fb.com>,
        Josef Bacik <josef@toxicpanda.com>,
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        "linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>,
        Matias =?iso-8859-1?Q?Bj=F8rling?= <Matias.Bjorling@wdc.com>,
        Damien Le Moal <dlemoal@kernel.org>
Subject: Re: don't split ordered_extents for zoned writes at I/O submission
 time
Message-ID: <20230530142009.GA8807@lst.de>
References: <20230524150317.1767981-1-hch@lst.de> <45d88c8a-4eab-6fc2-8970-6224878940a1@wdc.com>
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On Tue, May 30, 2023 at 01:21:14PM +0000, Johannes Thumshirn wrote:
> Btw, as this came up multiple times today, should we also add a patch on top
> of this series merging consecutive ordered extents if the on disk extents are
> consecutive as well?
> 
> This would reduce fragmentation that unfortunately is a byproduct of the
> Zone Append writing scheme.

With this series we don't split ordered extents for zoned writes unless
they are non-consecutive.  So I'm not sure what we should merge, as
there isn't any splitting going on unless either a block group didn't
have space, or zone append actually reordered.