From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1754363AbcIJHmd (ORCPT <rfc822;w@1wt.eu>);
        Sat, 10 Sep 2016 03:42:33 -0400
Received: from bombadil.infradead.org ([198.137.202.9]:45362 "EHLO
        bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1750812AbcIJHmb (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Sat, 10 Sep 2016 03:42:31 -0400
Date: Sat, 10 Sep 2016 00:42:28 -0700
From: Christoph Hellwig <hch@infradead.org>
To: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Christoph Hellwig <hch@infradead.org>,
        Ross Zwisler <ross.zwisler@linux.intel.com>,
        "Theodore Ts'o" <tytso@mit.edu>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        "linux-nvdimm@ml01.01.org" <linux-nvdimm@ml01.01.org>,
        Dave Chinner <david@fromorbit.com>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        Andreas Dilger <adilger.kernel@dilger.ca>,
        Alexander Viro <viro@zeniv.linux.org.uk>, Jan Kara <jack@suse.com>,
        "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
        "linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>
Subject: Re: [PATCH v2 2/9] ext2: tell DAX the size of allocation holes
Message-ID: <20160910074228.GA23749@infradead.org>
References: <20160823220419.11717-1-ross.zwisler@linux.intel.com>
 <20160823220419.11717-3-ross.zwisler@linux.intel.com>
 <20160825075728.GA11235@infradead.org>
 <20160826212934.GA11265@linux.intel.com>
 <20160829074116.GA16491@infradead.org>
 <20160829125741.cdnbb2uaditcmnw2@thunk.org>
 <20160909164808.GC18554@linux.intel.com>
 <DM2PR21MB0089BCA980B67D8C53B25A1BCBFA0@DM2PR21MB0089.namprd21.prod.outlook.com>
 <20160910073012.GA5295@infradead.org>
 <DM2PR21MB0089FDEE0F0939010189EB99CBFD0@DM2PR21MB0089.namprd21.prod.outlook.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <DM2PR21MB0089FDEE0F0939010189EB99CBFD0@DM2PR21MB0089.namprd21.prod.outlook.com>
User-Agent: Mutt/1.6.1 (2016-04-27)
X-SRS-Rewrite: SMTP reverse-path rewritten from <hch@infradead.org> by bombadil.infradead.org. See http://www.infradead.org/rpr.html
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Sat, Sep 10, 2016 at 07:33:18AM +0000, Matthew Wilcox wrote:
> > caller specific is unaceptable.  That being said your idea doesn't sounds
> > unreasonable, but will require a bit more work and has no real short-term
> > need.
> 
> So your proposal is to remove buffer_heads from ext2?

No, the proposal is to remove buffer_heads from XFS first, then GFS2
and then maybe others like ext4.  I'd like to remove buffer_heads from
the DAX path for ext2 and ext4 entitrely for sure (and direct I/O next).