Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754224AbbFVQsY (ORCPT ); Mon, 22 Jun 2015 12:48:24 -0400 Received: from verein.lst.de ([213.95.11.211]:43024 "EHLO newverein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752155AbbFVQsG (ORCPT ); Mon, 22 Jun 2015 12:48:06 -0400 Date: Mon, 22 Jun 2015 18:48:04 +0200 From: Christoph Hellwig To: Jeff Moyer Cc: Dan Williams , Jens Axboe , "linux-nvdimm@lists.01.org" , "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: <20150622164804.GA9393@lst.de> References: <20150622063028.GA30434@lst.de> <20150622072844.GA31263@lst.de> <20150622154138.GC7952@lst.de> <20150622163224.GA9168@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: 975 Lines: 18 On Mon, Jun 22, 2015 at 12:42:44PM -0400, Jeff Moyer wrote: > OK, add torn sector detection/recovery to that statement, then. More > importantly, do you agree with the sentiment or not? I think we're getting on a very slipper slope if we think about application here. Buffered I/O application must deal with torn writes at any granulairty anyway, e.g. fsync + rename is the only thing they can rely on right now (I actually have software O_ATOMIC code to avoid this, but that's another story). Direct I/O using application can make assumption if they know the sector size, and we must have a way for them to be able to see our new "subsector sector size". And thos application are few inbetween but also important so needing special cases for them is fine. Although those are the most likely ones to take advantage of byte addressing anyway. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/