From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org ([198.137.202.133]:47302 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751430AbeEPQYR (ORCPT ); Wed, 16 May 2018 12:24:17 -0400 Date: Wed, 16 May 2018 09:24:15 -0700 From: Christoph Hellwig Subject: Re: [PATCH] iomap: don't allow holes in swapfiles Message-ID: <20180516162415.GB21071@infradead.org> References: <20180516155000.GC23858@magnolia> <20180516155146.GA8294@infradead.org> <20180516155638.GD23858@magnolia> <20180516161955.GA14174@vader> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180516161955.GA14174@vader> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Omar Sandoval Cc: "Darrick J. Wong" , Christoph Hellwig , linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jan Kara , Aleksei Besogonov On Wed, May 16, 2018 at 09:19:55AM -0700, Omar Sandoval wrote: > > > Wasn't the desire to support holes the rationale for the Aleksei > > > version of the iomap swapfile patch? > > > > Ah, so it was. FWIW I'm not sure why you'd /want/ a holey swapfile? > > >From reading the old thread, it looks like Aleksei just wanted > fallocated swap files to work: "I've traced the problem to bmap(), used > in generic_swapfile_activate call, which returns 0 for blocks inside > holes created by fallocate". Oh, that makes more sense. > Are holes in that sense are different from > actual holes in the iomap sense? Unwritten extents aren't actually holes in any sense, so they are very different and should work with the iomap swapfile code.