From mboxrd@z Thu Jan  1 00:00:00 1970
From: Matthew Wilcox <willy@linux.intel.com>
Subject: Re: [PATCH v11 07/21] dax,ext2: Replace XIP read and write with DAX
 I/O
Date: Thu, 16 Oct 2014 15:51:12 -0400
Message-ID: <20141016195112.GE11522@wil.cx>
References: <1411677218-29146-1-git-send-email-matthew.r.wilcox@intel.com>
 <1411677218-29146-8-git-send-email-matthew.r.wilcox@intel.com>
 <20141016095027.GE19075@thinkos.etherlink>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>,
	linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Return-path: <linux-kernel-owner@vger.kernel.org>
Content-Disposition: inline
In-Reply-To: <20141016095027.GE19075@thinkos.etherlink>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: linux-fsdevel.vger.kernel.org

On Thu, Oct 16, 2014 at 11:50:27AM +0200, Mathieu Desnoyers wrote:
> > +			if (rw == WRITE) {
> > +				if (!buffer_mapped(bh)) {
> > +					retval = -EIO;
> > +					/* FIXME: fall back to buffered I/O */
> 
> Fallback on buffered I/O would void guarantee about having data stored
> into persistent memory after write returns. Not sure we actually want
> that.

Yeah, I think that comment is just stale.  I can't see a way in which
buffered I/O would succeed after DAX I/O falis.