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Date:   Mon, 2 Sep 2019 18:43:31 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Goldwyn Rodrigues <rgoldwyn@suse.de>
Cc:     linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org,
        darrick.wong@oracle.com, hch@lst.de, david@fromorbit.com,
        riteshh@linux.ibm.com
Subject: Re: [PATCH v3 0/15] Btrfs iomap
Message-ID: <20190902164331.GE6263@lst.de>
References: <20190901200836.14959-1-rgoldwyn@suse.de>
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On Sun, Sep 01, 2019 at 03:08:21PM -0500, Goldwyn Rodrigues wrote:
> This is an effort to use iomap for btrfs. This would keep most
> responsibility of page handling during writes in iomap code, hence
> code reduction. For CoW support, changes are needed in iomap code
> to make sure we perform a copy before the write.
> This is in line with the discussion we had during adding dax support in
> btrfs.

This looks pretty good modulo a few comments.

Can you please convert the XFS code to use your two iomaps for COW
approach as well to validate it?

Also the iomap_file_dirty helper would really benefit from using the
two iomaps, any chance you could look into improving it to use your
new infrastructure?