From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from verein.lst.de ([213.95.11.211]:57066 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725953AbeLUG13 (ORCPT ); Fri, 21 Dec 2018 01:27:29 -0500 Date: Fri, 21 Dec 2018 07:27:27 +0100 From: Christoph Hellwig Subject: Re: [PATCH 11/11] xfs: introduce an always_cow mode Message-ID: <20181221062727.GA31373@lst.de> References: <20181203222503.30649-1-hch@lst.de> <20181203222503.30649-12-hch@lst.de> <20181218232437.GS27208@magnolia> <20181219224335.GB4205@dastard> <20181220070741.GA9803@lst.de> <20181220210309.GE4205@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181220210309.GE4205@dastard> Sender: linux-xfs-owner@vger.kernel.org List-ID: List-Id: xfs To: Dave Chinner Cc: Christoph Hellwig , "Darrick J. Wong" , linux-xfs@vger.kernel.org On Fri, Dec 21, 2018 at 08:03:09AM +1100, Dave Chinner wrote: > Yes, I know it's not persistent, but do we care for always_cow mode? > Preallocation to prevent enospc is done just before the data is > written, and if we put it in the COW fork then it will mostly just > work and behave as expected for preventing ENOSPC on subsequent > writes. Preallocation to control data layout is largely irrelevant > to always_cow mode, so it really makes no difference to us if the > preallocation disappears when the inode is cycled out of cache.... I'll have to see if we can get the semantics for the right.