From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yw0-f174.google.com ([209.85.161.174]:34841 "EHLO mail-yw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750729AbdHRIFn (ORCPT ); Fri, 18 Aug 2017 04:05:43 -0400 Received: by mail-yw0-f174.google.com with SMTP id n83so26868675ywn.2 for ; Fri, 18 Aug 2017 01:05:43 -0700 (PDT) Date: Fri, 18 Aug 2017 01:05:39 -0700 From: Omar Sandoval To: Hannes Reinecke , Karel Zak Cc: linux-block@vger.kernel.org, kernel-team@fb.com, Ming Lei Subject: Re: [PATCH 1/2] loop: always return block size in LOOP_GET_STATUS Message-ID: <20170818080539.GI2459@vader> References: <9ff9b291e3e872698a040a281549c39c0637565f.1503036471.git.osandov@fb.com> <20170818073838.GG2459@vader> <3f01f907-0443-4961-d4fd-a5a3ffe8e688@suse.de> <20170818074700.GH2459@vader> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org On Fri, Aug 18, 2017 at 09:56:26AM +0200, Hannes Reinecke wrote: > On 08/18/2017 09:47 AM, Omar Sandoval wrote: > > On Fri, Aug 18, 2017 at 09:43:19AM +0200, Hannes Reinecke wrote: > >> On 08/18/2017 09:38 AM, Omar Sandoval wrote: > >>> On Fri, Aug 18, 2017 at 09:18:52AM +0200, Hannes Reinecke wrote: > [ .. ] > >>>> I've got quite some flak for daring to break existing interfaces, most > >>>> notably setting logical and physical blocksize per default (which I > >>>> would _love_ to have done, seeing that it really makes sense here). > >>>> But as this would change the behaviour I've gone through pains (and > >>>> several _years_ of iterations) to get this sorted. > >>>> > >>>> So if you design a blocktest for that ensure that > >>>> a) the sysfs attributes before and after the patch are _identical_ > >>>> b) the sysfs attributes will only change if the 'LO_FLAGS_BLOCKSIZE' > >>>> flag has been set > >>>> and > >>>> c) validate the written blocksizes; this is required to be able to > >>>> install bootloaders there > >>>> > >>>> This whole interface was designed such that you can prepare bootable > >>>> diskimages for S/390 DASDs, which use a native 4k blocksize. > >>> > >>> Hi, Hannes, > >>> > >>> Wasn't insulting you at all, the only part of the interface I'm > >>> complaining about is LOOP_GET_STATUS missing information :) > >>> > >> Sure. Just saying. > >> But please make sure only to return that information if the > >> LO_FLAGS_BLOCKSIZE flag is set; otherwise there's a rick of confusing > >> losetup. > > > > I actually checked losetup, it works just fine with LO_FLAGS_BLOCKSIZE > > always set and lo_init[0] always filled in. > > > The original argument I had with the util-linux maintainer did not > revolve so much around technical details :-) Karel, what were your concerns here?