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=-5.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 B38F6C2D0A8 for ; Mon, 28 Sep 2020 14:37:14 +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 413D82075A for ; Mon, 28 Sep 2020 14:37:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="doeHNzax" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 413D82075A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:60186 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kMuHB-0007hy-2S for qemu-devel@archiver.kernel.org; Mon, 28 Sep 2020 10:37:13 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56148) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kMuFv-0006QF-9I for qemu-devel@nongnu.org; Mon, 28 Sep 2020 10:35:55 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:31701) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kMuFp-0005It-Hu for qemu-devel@nongnu.org; Mon, 28 Sep 2020 10:35:55 -0400 Dkim-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1601303748; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=MWFumjoqgqaxg7Lw/kkvNKiYd0uqtrru8F0pQ5H5hLM=; b=doeHNzaxRxJ5pcWEax71neIsW8XIMvMwyzUlT0aU9u2IxoMhc6wEXLKEPlH/omtlAGn74+ uHIiD5nFxZj423AFxds5oIAXh7UDHDrW5X76PdqSFATCOE4csRZe23vzK7LkZ6WybFYyaE T0jew5n9nO4DquaSfn3InMz518XHFS8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-425-5tSahJ-wPGe42Fniu8KLuA-1; Mon, 28 Sep 2020 10:35:45 -0400 X-MC-Unique: 5tSahJ-wPGe42Fniu8KLuA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7F6511019624; Mon, 28 Sep 2020 14:35:44 +0000 (UTC) Received: from [10.3.112.208] (ovpn-112-208.phx2.redhat.com [10.3.112.208]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E463B55799; Mon, 28 Sep 2020 14:35:43 +0000 (UTC) Subject: Re: [PATCH 3/3] nbd: Add 'qemu-nbd -A' to expose allocation depth To: Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org References: <20200925203249.155705-1-eblake@redhat.com> <20200925203249.155705-4-eblake@redhat.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: <5908bfab-f9ab-bbb9-5a47-85c38c1040e5@redhat.com> Date: Mon, 28 Sep 2020 09:35:43 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eblake@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/28 03:29:35 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.687, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action 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: Kevin Wolf , pkrempa@redhat.com, qemu-block@nongnu.org, Markus Armbruster , rjones@redhat.com, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 9/26/20 8:32 AM, Vladimir Sementsov-Ogievskiy wrote: > 25.09.2020 23:32, Eric Blake wrote: >> Allow the server to expose an additional metacontext to be requested >> by savvy clients.  qemu-nbd adds a new option -A to expose the >> qemu:allocation-depth metacontext through NBD_CMD_BLOCK_STATUS; this >> can also be set via QMP when using nbd-server-add. >> >> qemu as client can be hacked into viewing this new context by using >> the now-misnamed x-dirty-bitmap option when creating an NBD blockdev; > > may be rename it to x-block-status ? I thought about it. We don't promise any back-compat with x- prefix, but at the same time, if there's not a strong reason to change it, scripts written against older qemu will not break as long as we still have the hack. > >> although it is worth noting the decoding of how such context >> information will appear in 'qemu-img map --output=json': >> >> NBD_STATE_DEPTH_UNALLOC => "zero":false, "data":true >> NBD_STATE_DEPTH_LOCAL => "zero":false, "data":false >> NBD_STATE_DEPTH_BACKING => "zero":true, "data":true > > It wouldn't be so simple if we decide to export exact depth number.. It's still simple to do tri-state results if we separate the exact depth number to bits 31-4, leaving bits 1-0 as the tri-state summary... -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org