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=-0.8 required=3.0 tests=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 CEB1AC2BA83 for ; Wed, 12 Feb 2020 07:31:29 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A1B86206DB for ; Wed, 12 Feb 2020 07:31:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A1B86206DB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=uter.be Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:32972 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j1mUa-0006ea-Lh for qemu-devel@archiver.kernel.org; Wed, 12 Feb 2020 02:31:28 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:55808) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j1mRB-00057q-D6 for qemu-devel@nongnu.org; Wed, 12 Feb 2020 02:27:58 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j1mRA-0004kk-EA for qemu-devel@nongnu.org; Wed, 12 Feb 2020 02:27:57 -0500 Received: from latin.grep.be ([2a01:4f8:140:52e5::2]:34962) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j1mRA-0004ZK-8V; Wed, 12 Feb 2020 02:27:56 -0500 Received: from [105.186.91.62] (helo=gangtai.home.grep.be) by latin.grep.be with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1j1mQs-0003OD-RC; Wed, 12 Feb 2020 08:27:38 +0100 Received: from wouter by gangtai.home.grep.be with local (Exim 4.93) (envelope-from ) id 1j1mQj-0006QW-NK; Wed, 12 Feb 2020 09:27:29 +0200 Date: Wed, 12 Feb 2020 09:27:29 +0200 From: Wouter Verhelst To: "Richard W.M. Jones" Subject: Re: Cross-project NBD extension proposal: NBD_INFO_INIT_STATE Message-ID: <20200212072729.GA22254@grep.be> References: <20200210221234.GH3888@redhat.com> <20200210225255.GJ3888@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200210225255.GJ3888@redhat.com> X-Speed: Gates' Law: Every 18 months, the speed of software halves. Organization: none X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2a01:4f8:140:52e5::2 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Vladimir Sementsov-Ogievskiy , Alberto Garcia , "qemu-block@nongnu.org" , QEMU , Max Reitz , "nbd@other.debian.org" , "libguestfs@redhat.com" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi, On Mon, Feb 10, 2020 at 10:52:55PM +0000, Richard W.M. Jones wrote: > But anyway ... could a flag indicating that the whole image is sparse > be useful, either as well as NBD_INIT_SPARSE or instead of it? You > could use it to avoid an initial disk trim, which is something that > mke2fs does: Yeah, I think that could definitely be useful. I honestly can't see a use for NBD_INIT_SPARSE as defined in this proposal; and I don't think it's generally useful to have a feature if we can't think of a use case for it (that creates added complexity for no benefit). If we can find a reasonable use case for NBD_INIT_SPARSE as defined in this proposal, then just add a third bit (NBD_INIT_ALL_SPARSE or something) that says "the whole image is sparse". Otherwise, I think we should redefine NBD_INIT_SPARSE to say that. -- To the thief who stole my anti-depressants: I hope you're happy -- seen somewhere on the Internet on a photo of a billboard