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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 63065C2D0E7 for ; Thu, 26 Mar 2020 09:29:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 376D52073E for ; Thu, 26 Mar 2020 09:29:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="olbIXlgR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727860AbgCZJ36 (ORCPT ); Thu, 26 Mar 2020 05:29:58 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:39720 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726540AbgCZJ36 (ORCPT ); Thu, 26 Mar 2020 05:29:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=dG5pPHs14OBzWSVcRXLG0d0hpdMtIjiZ05XYggJN7Nw=; b=olbIXlgRMRYIuRBimP12omMlMf qniCU91DEn3QcBZif8E9ZHHXEHuxyEImoFcq421j3RYxfsEGB4HIt4ACQMQ4A52je9dlbLNu+l9R2 DCZGhCnkyzbZKJdgbvSkRV5SR3Z76Zm71qw/x2GRBhrZ5B+iV4mAktYlQmLh6fbv+zN2SDyeJyiAr TMy9g1dH4+NmPyjVbAg/uKUnOvvBCDTSvrPPPmCgESua3nLpqouFCD4kGGDuSYC+U3fPKzTxmbCvM c6TPM73XIQ/CTiAQ0ucsBmDkG6gRa81JKCjhoMNeOHD3XAEpMwKBj4ZiWY77jkfq4kZk/3kctdhWI liblYJtA==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jHOpT-0001iz-SO; Thu, 26 Mar 2020 09:29:35 +0000 Date: Thu, 26 Mar 2020 02:29:35 -0700 From: Christoph Hellwig To: "Martin K. Petersen" Cc: Christoph Hellwig , "Darrick J. Wong" , Kirill Tkhai , axboe@kernel.dk, bob.liu@oracle.com, agk@redhat.com, snitzer@redhat.com, dm-devel@redhat.com, song@kernel.org, tytso@mit.edu, adilger.kernel@dilger.ca, Chaitanya.Kulkarni@wdc.com, ming.lei@redhat.com, osandov@fb.com, jthumshirn@suse.de, minwoo.im.dev@gmail.com, damien.lemoal@wdc.com, andrea.parri@amarulasolutions.com, hare@suse.com, tj@kernel.org, ajay.joshi@wdc.com, sagi@grimberg.me, dsterba@suse.com, bvanassche@acm.org, dhowells@redhat.com, asml.silence@gmail.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v7 0/6] block: Introduce REQ_ALLOCATE flag for REQ_OP_WRITE_ZEROES Message-ID: <20200326092935.GA6478@infradead.org> References: <158157930219.111879.12072477040351921368.stgit@localhost.localdomain> <69c0b8a4-656f-98c4-eb55-2fd1184f5fc9@virtuozzo.com> <67d63190-c16f-cd26-6b67-641c8943dc3d@virtuozzo.com> <20200319102819.GA26418@infradead.org> <20200325162656.GJ29351@magnolia> <20200325163223.GA27156@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Wed, Mar 25, 2020 at 01:23:33PM -0400, Martin K. Petersen wrote: > > Christoph, > > > I am very much against that for the following reason: > > > > - the current REQ_OP_DISCARD is purely a hint, and implementations can > > (and do) choose to ignore it > > > > - REQ_OP_WRITE_ZEROES is an actual data integrity operation with > > everything that entails > > If you want to keep emphasis on the "integrity operation" instead of the > provisioning aspect, would you expect REQ_ALLOCATE (which may or may not > zero blocks) to be considered a deterministic operation or a > non-deterministic one? Should this depend on whether the device > guarantees zeroing when provisioning blocks or not? That's why I don't like the whole flags game very much. I'd rather have REQ_OP_WRITE_ZEROES as the integrity operation that gurantees zeroing, and a REQ_ALLOCATE that doesn't guarantee zeroing, just some deterministic state of the blocks.