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 S1756026AbcIJRv7 (ORCPT <rfc822;w@1wt.eu>);
        Sat, 10 Sep 2016 13:51:59 -0400
Received: from imap.thunk.org ([74.207.234.97]:36968 "EHLO imap.thunk.org"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1754945AbcIJRv4 (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Sat, 10 Sep 2016 13:51:56 -0400
Date: Sat, 10 Sep 2016 13:49:10 -0400
From: "Theodore Ts'o" <tytso@mit.edu>
To: Christoph Hellwig <hch@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>,
        Matthew Wilcox <mawilcox@microsoft.com>,
        Ross Zwisler <ross.zwisler@linux.intel.com>,
        "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: <20160910174910.yyirb7smiob7evt5@thunk.org>
Mail-Followup-To: Theodore Ts'o <tytso@mit.edu>,
        Christoph Hellwig <hch@infradead.org>,
        Dan Williams <dan.j.williams@intel.com>,
        Matthew Wilcox <mawilcox@microsoft.com>,
        Ross Zwisler <ross.zwisler@linux.intel.com>,
        "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>
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>
 <CAPcyv4hjna08+Yw23w_V2f-RbBE6ar220+YGCuBVA-TACKWNug@mail.gmail.com>
 <20160910073151.GB5295@infradead.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20160910073151.GB5295@infradead.org>
User-Agent: NeoMutt/ (1.7.0)
X-SA-Exim-Connect-IP: <locally generated>
X-SA-Exim-Mail-From: tytso@thunk.org
X-SA-Exim-Scanned: No (on imap.thunk.org); SAEximRunCond expanded to false
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 12:31:51AM -0700, Christoph Hellwig wrote:
> I've mentioned this before, but I'd like to repeat it.  With all the
> work reqwuired in the file system I would prefer to drop DAX support
> in ext2 (and if people really cry for it reinstate the trivial old xip
> support).

Why is so much work required to support the new DAX interfaces in
ext2?  Is that unique to ext2, or is adding DAX support just going to
be painful for all file systems?  Hopefully it's not the latter,
right?

						- Ted