From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933108AbcFOVYY (ORCPT ); Wed, 15 Jun 2016 17:24:24 -0400 Received: from silver.sucs.swan.ac.uk ([137.44.10.1]:57393 "EHLO silver.sucs.swan.ac.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932950AbcFOVYW (ORCPT ); Wed, 15 Jun 2016 17:24:22 -0400 Date: Wed, 15 Jun 2016 22:24:14 +0100 From: Sitsofe Wheeler To: "Martin K. Petersen" Cc: Christoph Hellwig , Shaohua Li , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, axboe@fb.com, sitsofe@yahoo.com, snitzer@redhat.com, Kernel-team@fb.com Subject: Re: [PATCH V2] block: correctly fallback for zeroout Message-ID: <20160615212414.GA5410@sucs.org> References: <20160606223357.GA52883@shli-mbp.local> <20160610025435.GA48899@shli-mbp.local> <20160613082001.GA27508@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 14, 2016 at 10:14:50PM -0400, Martin K. Petersen wrote: > >>>>> "Christoph" == Christoph Hellwig writes: > > Christoph> And I'd much prefer to get this right now. It's not like > Christoph> this is recently introduced behavior. > > Unfortunately there are quite a few callers of blkdev_issue_discard() > these days. Some of them ignore the return value but not all of > them. I'm concerned about causing all sorts of breakage if we suddenly > start returning errors various places in the stable trees. This is true. We have problematic behaviour in stable kernels today so there needs to be a "least intrusive" workaround which changes the behaviour as little as possible for those. I would say that means maintaining the current -EOPNOTSUPP behaviour in those kernels regardless of what goes into master. -- Sitsofe | http://sucs.org/~sits/