From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A2746C0650E for ; Wed, 3 Jul 2019 14:21:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8223421881 for ; Wed, 3 Jul 2019 14:21:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726305AbfGCOV4 (ORCPT ); Wed, 3 Jul 2019 10:21:56 -0400 Received: from mail.parknet.co.jp ([210.171.160.6]:54098 "EHLO mail.parknet.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725830AbfGCOVz (ORCPT ); Wed, 3 Jul 2019 10:21:55 -0400 X-Greylist: delayed 480 seconds by postgrey-1.27 at vger.kernel.org; Wed, 03 Jul 2019 10:21:54 EDT Received: from ibmpc.myhome.or.jp (server.parknet.ne.jp [210.171.168.39]) by mail.parknet.co.jp (Postfix) with ESMTPSA id 33C231B457B; Wed, 3 Jul 2019 23:13:54 +0900 (JST) Received: from devron.myhome.or.jp (foobar@devron.myhome.or.jp [192.168.0.3]) by ibmpc.myhome.or.jp (8.15.2/8.15.2/Debian-12) with ESMTPS id x63EDqx6010978 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Wed, 3 Jul 2019 23:13:53 +0900 Received: from devron.myhome.or.jp (foobar@localhost [127.0.0.1]) by devron.myhome.or.jp (8.15.2/8.15.2/Debian-12) with ESMTPS id x63EDquc026641 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Wed, 3 Jul 2019 23:13:52 +0900 Received: (from hirofumi@localhost) by devron.myhome.or.jp (8.15.2/8.15.2/Submit) id x63EDql7026640; Wed, 3 Jul 2019 23:13:52 +0900 From: OGAWA Hirofumi To: Andrew Morton Cc: Christoph Hellwig , stable@vger.kernel.org Subject: Re: + fat-add-nobarrier-to-workaround-the-strange-behavior-of-device.patch added to -mm tree References: <20190702224959.sBsBg%akpm@linux-foundation.org> <20190702225053.GA24248@lst.de> <20190702160343.0b1fd99491f7b257f68ad82c@linux-foundation.org> Date: Wed, 03 Jul 2019 23:13:52 +0900 In-Reply-To: <20190702160343.0b1fd99491f7b257f68ad82c@linux-foundation.org> (Andrew Morton's message of "Tue, 2 Jul 2019 16:03:43 -0700") Message-ID: <87pnmrjjdr.fsf@mail.parknet.co.jp> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Andrew Morton writes: > On Wed, 3 Jul 2019 00:50:53 +0200 Christoph Hellwig wrote: > >> I still very fundamentally disagree with this patch. We did a concerted >> effort around the other file systems to move to the device level tweak >> and remove the badly misnamed option, so we should not add it now for >> fat. > > OK, thanks, I'll leave it on hold for now. I've checked v5.1, you mentioned "cache_type" (scsi specific unfortunately). It calls blk_queue_write_cache(), so it calls wbt_set_write_cache() too. So it affects to writeback throttling. Is this intended one? At least, it was not what I expected. It is why I asked side effect of it repeatedly in that thread. True candidate looks like block layer's "write_cache" introduced after v4.6. It doesn't call wbt_set_write_cache(). However, I worry if this is intent or bug, behave like "cache_type". Did this get consensus to replace "nobarrier" (I hope so)? If not, I even can't recommend "write_cache", instead of "nobarrier" as documenting, and we need real replacement to just disable flush command. Thanks. -- OGAWA Hirofumi