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[213.95.11.211]) by mx.google.com with ESMTPS id v4si14347767wmj.132.2019.04.25.00.59.48 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 25 Apr 2019 00:59:48 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of hch@lst.de designates 213.95.11.211 as permitted sender) client-ip=213.95.11.211; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of hch@lst.de designates 213.95.11.211 as permitted sender) smtp.mailfrom=hch@lst.de Received: by newverein.lst.de (Postfix, from userid 2407) id 689A368AFE; Thu, 25 Apr 2019 09:59:33 +0200 (CEST) Date: Thu, 25 Apr 2019 09:59:33 +0200 From: Christoph Hellwig To: Andreas Gruenbacher Cc: cluster-devel@redhat.com, Christoph Hellwig , Bob Peterson , Jan Kara , Dave Chinner , Ross Lagerwall , Mark Syms , Edwin =?iso-8859-1?B?VPZy9ms=?= , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 1/2] iomap: Add a page_prepare callback Message-ID: <20190425075933.GA9374@lst.de> References: <20190424171804.4305-1-agruenba@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190424171804.4305-1-agruenba@redhat.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Apr 24, 2019 at 07:18:03PM +0200, Andreas Gruenbacher wrote: > Add a page_prepare calback that's called before a page is written to. This > will be used by gfs2 to start a transaction in page_prepare and end it in > page_done. Other filesystems that implement data journaling will require the > same kind of mechanism. This looks basically fine to me. But I think it would be nicer to add a iomap_page_ops structure so that we don't have to add more pointers directly to the iomap. We can make that struct pointer const also to avoid runtime overwriting attacks.