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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 46471C3A5A2 for ; Fri, 23 Aug 2019 21:18:21 +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 0FB2321874 for ; Fri, 23 Aug 2019 21:18:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0FB2321874 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]:34240 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i1Gwu-00072y-2I for qemu-devel@archiver.kernel.org; Fri, 23 Aug 2019 17:18:20 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:33772) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i1Gv7-0006Sk-FK for qemu-devel@nongnu.org; Fri, 23 Aug 2019 17:16:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i1Gv6-0000XX-F8 for qemu-devel@nongnu.org; Fri, 23 Aug 2019 17:16:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52522) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1i1Gv3-0000Wi-A6; Fri, 23 Aug 2019 17:16:25 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D84CD3082D9E; Fri, 23 Aug 2019 21:16:23 +0000 (UTC) Received: from [10.3.116.234] (ovpn-116-234.phx2.redhat.com [10.3.116.234]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A3FC91001284; Fri, 23 Aug 2019 21:16:19 +0000 (UTC) To: libguestfs@redhat.com References: <25ead363-4f37-5450-b985-1876374e314d@redhat.com> <20190823144054.27420-1-eblake@redhat.com> <20190823144054.27420-4-eblake@redhat.com> From: Eric Blake Openpgp: preference=signencrypt Autocrypt: addr=eblake@redhat.com; keydata= xsBNBEvHyWwBCACw7DwsQIh0kAbUXyqhfiKAKOTVu6OiMGffw2w90Ggrp4bdVKmCaEXlrVLU xphBM8mb+wsFkU+pq9YR621WXo9REYVIl0FxKeQo9dyQBZ/XvmUMka4NOmHtFg74nvkpJFCD TUNzmqfcjdKhfFV0d7P/ixKQeZr2WP1xMcjmAQY5YvQ2lUoHP43m8TtpB1LkjyYBCodd+LkV GmCx2Bop1LSblbvbrOm2bKpZdBPjncRNob73eTpIXEutvEaHH72LzpzksfcKM+M18cyRH+nP sAd98xIbVjm3Jm4k4d5oQyE2HwOur+trk2EcxTgdp17QapuWPwMfhaNq3runaX7x34zhABEB AAHNHkVyaWMgQmxha2UgPGVibGFrZUByZWRoYXQuY29tPsLAegQTAQgAJAIbAwULCQgHAwUV CgkICwUWAgMBAAIeAQIXgAUCS8fL9QIZAQAKCRCnoWtKJSdDahBHCACbl/5FGkUqJ89GAjeX RjpAeJtdKhujir0iS4CMSIng7fCiGZ0fNJCpL5RpViSo03Q7l37ss+No+dJI8KtAp6ID+PMz wTJe5Egtv/KGUKSDvOLYJ9WIIbftEObekP+GBpWP2+KbpADsc7EsNd70sYxExD3liwVJYqLc Rw7so1PEIFp+Ni9A1DrBR5NaJBnno2PHzHPTS9nmZVYm/4I32qkLXOcdX0XElO8VPDoVobG6 gELf4v/vIImdmxLh/w5WctUpBhWWIfQDvSOW2VZDOihm7pzhQodr3QP/GDLfpK6wI7exeu3P pfPtqwa06s1pae3ad13mZGzkBdNKs1HEm8x6zsBNBEvHyWwBCADGkMFzFjmmyqAEn5D+Mt4P zPdO8NatsDw8Qit3Rmzu+kUygxyYbz52ZO40WUu7EgQ5kDTOeRPnTOd7awWDQcl1gGBXgrkR pAlQ0l0ReO57Q0eglFydLMi5bkwYhfY+TwDPMh3aOP5qBXkm4qIYSsxb8A+i00P72AqFb9Q7 3weG/flxSPApLYQE5qWGSXjOkXJv42NGS6o6gd4RmD6Ap5e8ACo1lSMPfTpGzXlt4aRkBfvb NCfNsQikLZzFYDLbQgKBA33BDeV6vNJ9Cj0SgEGOkYyed4I6AbU0kIy1hHAm1r6+sAnEdIKj cHi3xWH/UPrZW5flM8Kqo14OTDkI9EtlABEBAAHCwF8EGAEIAAkFAkvHyWwCGwwACgkQp6Fr SiUnQ2q03wgAmRFGDeXzc58NX0NrDijUu0zx3Lns/qZ9VrkSWbNZBFjpWKaeL1fdVeE4TDGm I5mRRIsStjQzc2R9b+2VBUhlAqY1nAiBDv0Qnt+9cLiuEICeUwlyl42YdwpmY0ELcy5+u6wz mK/jxrYOpzXKDwLq5k4X+hmGuSNWWAN3gHiJqmJZPkhFPUIozZUCeEc76pS/IUN72NfprZmF Dp6/QDjDFtfS39bHSWXKVZUbqaMPqlj/z6Ugk027/3GUjHHr8WkeL1ezWepYDY7WSoXwfoAL 2UXYsMAr/uUncSKlfjvArhsej0S4zbqim2ZY6S8aRWw94J3bSvJR+Nwbs34GPTD4Pg== Organization: Red Hat, Inc. Message-ID: <0f743b37-6308-24d0-eae0-5f939af9dae2@redhat.com> Date: Fri, 23 Aug 2019 16:16:18 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190823144054.27420-4-eblake@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="eXYbbBvIJTxpYUqAQfsoypeWf7DejGVhK" X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.46]); Fri, 23 Aug 2019 21:16:23 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [Libguestfs] [nbdkit PATCH 3/3] plugins: Add .can_fast_zero hook 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: qemu-devel@nongnu.org, qemu-block@nongnu.org, nbd@other.debian.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --eXYbbBvIJTxpYUqAQfsoypeWf7DejGVhK Content-Type: multipart/mixed; boundary="0qmAS2y8KMZdV53c81xIWwAhFPnUp50lQ"; protected-headers="v1" From: Eric Blake To: libguestfs@redhat.com Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, nbd@other.debian.org Message-ID: <0f743b37-6308-24d0-eae0-5f939af9dae2@redhat.com> Subject: Re: [Libguestfs] [nbdkit PATCH 3/3] plugins: Add .can_fast_zero hook References: <25ead363-4f37-5450-b985-1876374e314d@redhat.com> <20190823144054.27420-1-eblake@redhat.com> <20190823144054.27420-4-eblake@redhat.com> In-Reply-To: <20190823144054.27420-4-eblake@redhat.com> --0qmAS2y8KMZdV53c81xIWwAhFPnUp50lQ Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 8/23/19 9:40 AM, Eric Blake wrote: > Allow plugins to affect the handling of the new NBD_CMD_FLAG_FAST_ZERO > flag, then update affected plugins. In particular, in-memory plugins > are always fast; the full plugin is better served by omitting .zero > and relying on .pwrite fallback; nbd takes advantage of libnbd > extensions proposed in parallel to pass through support; and > v2 language bindings expose the choice to their scripts. >=20 > +++ b/server/plugins.c > @@ -404,11 +404,25 @@ plugin_can_zero (struct backend *b, struct connec= tion *conn) > static int > plugin_can_fast_zero (struct backend *b, struct connection *conn) > { > + struct backend_plugin *p =3D container_of (b, struct backend_plugin,= backend); > + int r; > + > assert (connection_get_handle (conn, 0)); >=20 > debug ("can_fast_zero"); >=20 > - return 0; /* Upcoming patch will actually add support. */ > + if (p->plugin.can_fast_zero) > + return p->plugin.can_fast_zero (connection_get_handle (conn, 0)); > + /* Advertise support for fast zeroes if no .zero or .can_zero is > + * false: in those cases, we fail fast instead of using .pwrite. > + * This also works when v1 plugin has only ._zero_old. > + */ > + if (p->plugin.zero =3D=3D NULL) > + return 1; > + r =3D plugin_can_zero (b, conn); > + if (r =3D=3D -1) > + return -1; > + return !r; > } >=20 Needs this squashed in for libnbd to pass rather than skip its new 'can-fast-zero-flag' test: diff --git i/server/plugins.c w/server/plugins.c index 84329cf4..695a77ab 100644 --- i/server/plugins.c +++ w/server/plugins.c @@ -208,6 +208,7 @@ plugin_dump_fields (struct backend *b) HAS (can_cache); HAS (cache); HAS (thread_model); + HAS (can_fast_zero); #undef HAS /* Custom fields. */ --=20 Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org --0qmAS2y8KMZdV53c81xIWwAhFPnUp50lQ-- --eXYbbBvIJTxpYUqAQfsoypeWf7DejGVhK Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEccLMIrHEYCkn0vOqp6FrSiUnQ2oFAl1gV6IACgkQp6FrSiUn Q2pzvQf/cfNQ7g1RZfUxUI16kEkNzxpc7agCkznqsk7hJqz7Nj5vOPMGsCt3lldK AFLU5FB8BG0M2K+nEQcEHcMzIKuxi7FWFRZIC+sCQs835uurJcUixRI0uw+3SBUB EEJwXZc6hr4SCXrbckIyFD8ZD9HZZkCuQRmzJnAssM/Q0dsZ6iVwtdOAcLEeByV3 mD1uiXYq2SENXLCM0vkcjwSMIJwMhnHG6E68/gNy/AWg+//zyZRqxOlUNsBvlbjS 3ejiTuylA2cyfU18V4aISVQVgBQ0tlTDTryEcQxLCfw7+jFDo+G246Vc/fRfLTrY iPU96F0R1q7Ml4YJlmIjnXtrk0saaw== =l5dh -----END PGP SIGNATURE----- --eXYbbBvIJTxpYUqAQfsoypeWf7DejGVhK--