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Date:   Mon, 30 Sep 2019 13:10:47 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     "Darrick J. Wong" <darrick.wong@oracle.com>
Cc:     Christoph Hellwig <hch@lst.de>,
        Goldwyn Rodrigues <rgoldwyn@suse.com>,
        linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 10/19] xfs: pass two imaps to xfs_reflink_allocate_cow
Message-ID: <20190930111047.GB6987@lst.de>
References: <20190909182722.16783-1-hch@lst.de> <20190909182722.16783-11-hch@lst.de> <20190918172617.GB2229799@magnolia>
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On Wed, Sep 18, 2019 at 10:26:17AM -0700, Darrick J. Wong wrote:
> Hmm.  At first I thought this was a behavior change but I think it isn't
> because prior to this patch we'd set cmap = imap and if _allocate_cow
> didn't find a shared extent then it would just return without doing
> anything or touching cmap.  In the !shared case this would just set imap
> to itself pointlessly.
> 
> Now that we pass both imap and cmap to _allocate_cow, in the !shared
> case we don't initialized cmap at all, so adding the @shared check is
> required for correct operation, right?

Exactly.