Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933002AbbFVH2z (ORCPT ); Mon, 22 Jun 2015 03:28:55 -0400 Received: from verein.lst.de ([213.95.11.211]:40937 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752787AbbFVH2q (ORCPT ); Mon, 22 Jun 2015 03:28:46 -0400 Date: Mon, 22 Jun 2015 09:28:44 +0200 From: Christoph Hellwig To: Dan Williams Cc: Jens Axboe , "linux-nvdimm@lists.01.org" , Boaz Harrosh , "Kani, Toshimitsu" , "linux-kernel@vger.kernel.org" , Linux ACPI , linux-fsdevel , Ingo Molnar Subject: Re: [PATCH 14/15] libnvdimm: support read-only btt backing devices Message-ID: <20150622072844.GA31263@lst.de> References: <20150617235209.12943.24419.stgit@dwillia2-desk3.amr.corp.intel.com> <20150617235602.12943.24958.stgit@dwillia2-desk3.amr.corp.intel.com> <20150621101346.GF5915@lst.de> <20150621135406.GA9572@lst.de> <20150622063028.GA30434@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 846 Lines: 20 On Mon, Jun 22, 2015 at 12:17:29AM -0700, Dan Williams wrote: > To be fair the namespace was initially envisioned to be btt enabled or > not, and hide the raw media device. What's the fascination with hiding one access mode just because another one is available? > There's no guarantee that these drivers are only ever paired with > XFSv5. There's not guarantee for anything. Note that anything not following my criteria earlier would need some form of atomic sector updates, which is a lot more. But then again for most of those setups you wouldn't take advantage of pmem anyway. Sounds like we simply shouldn't merge btt at all for now and wait for a real use case, which would simplify the whole issue a lot. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/