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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 99557C3A589 for ; Thu, 15 Aug 2019 21:25:29 +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 54CC0205F4 for ; Thu, 15 Aug 2019 21:25:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 54CC0205F4 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]:47160 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1hyNFQ-00082S-FX for qemu-devel@archiver.kernel.org; Thu, 15 Aug 2019 17:25:28 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58739) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1hyNEj-0007Mv-Ei for qemu-devel@nongnu.org; Thu, 15 Aug 2019 17:24:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hyNEh-0007ZH-WE for qemu-devel@nongnu.org; Thu, 15 Aug 2019 17:24:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42306) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hyNEe-0007Xn-Un; Thu, 15 Aug 2019 17:24:41 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 14B93C04D2E2; Thu, 15 Aug 2019 21:24:40 +0000 (UTC) Received: from [10.18.17.169] (dhcp-17-169.bos.redhat.com [10.18.17.169]) by smtp.corp.redhat.com (Postfix) with ESMTP id 05CBA91E94; Thu, 15 Aug 2019 21:24:35 +0000 (UTC) To: Peter Krempa References: <20190814100735.24234-1-vsementsov@virtuozzo.com> <20190814100735.24234-2-vsementsov@virtuozzo.com> <6c40950f-c8b8-f9c7-6187-aa282e1a2d30@redhat.com> <20190815074459.GN300@andariel.pipo.sk> From: John Snow Openpgp: preference=signencrypt Autocrypt: addr=jsnow@redhat.com; prefer-encrypt=mutual; keydata= mQINBFTKefwBEAChvwqYC6saTzawbih87LqBYq0d5A8jXYXaiFMV/EvMSDqqY4EY6whXliNO IYzhgrPEe7ZmPxbCSe4iMykjhwMh5byIHDoPGDU+FsQty2KXuoxto+ZdrP9gymAgmyqdk3aV vzzmCa3cOppcqKvA0Kqr10UeX/z4OMVV390V+DVWUvzXpda45/Sxup57pk+hyY52wxxjIqef rj8u5BN93s5uCVTus0oiVA6W+iXYzTvVDStMFVqnTxSxlpZoH5RGKvmoWV3uutByQyBPHW2U 1Y6n6iEZ9MlP3hcDqlo0S8jeP03HaD4gOqCuqLceWF5+2WyHzNfylpNMFVi+Hp0H/nSDtCvQ ua7j+6Pt7q5rvqgHvRipkDDVsjqwasuNc3wyoHexrBeLU/iJBuDld5iLy+dHXoYMB3HmjMxj 3K5/8XhGrDx6BDFeO3HIpi3u2z1jniB7RtyVEtdupED6lqsDj0oSz9NxaOFZrS3Jf6z/kHIf h42mM9Sx7+s4c07N2LieUxcfqhFTaa/voRibF4cmkBVUhOD1AKXNfhEsTvmcz9NbUchCkcvA T9119CrsxfVsE7bXiGvdXnzyGLXdsoosjzwacKdOrVaDmN3Uy+SHiQXo6TlkSdV0XH2PUxTM LsBFIO9qXO43Ai6J6iPAP/01l8fuZfpJE0/L/c25yyaND7xA3wARAQABtCpKb2huIFNub3cg KEpvaG4gSHVzdG9uKSA8anNub3dAcmVkaGF0LmNvbT6JAlQEEwECAD4CGwMCHgECF4AFCwkI BwMFFQoJCAsFFgIDAQAWIQT665cRoSz0dYEvGPKIqQZNGDVh6wUCXF392gUJC1Xq3gAKCRCI qQZNGDVh6558D/9pM4pu4njX5aT6uUW3vAmbWLF1jfPxiTQgSHAnm9EBMZED/fsvkzj97clo LN7JKmbYZNgJmR01A7flG45V4iOR/249qAfaVuD+ZzZi1R4jFzr13WS+IEdn0hYp9ITndb7R ezW+HGu6/rP2PnfmDnNowgJu6Dp6IUEabq8SXXwGHXZPuMIrsXJxUdKJdGnh1o2u7271yNO7 J9PEMuMDsgjsdnaGtv7aQ9CECtXvBleAc06pLW2HU10r5wQyBMZGITemJdBhhdzGmbHAL0M6 vKi/bafHRWqfMqOAdDkv3Jg4arl2NCG/uNateR1z5e529+UlB4XVAQT+f5T/YyI65DFTY940 il3aZhA8u788jZEPMXmt94u7uPZbEYp7V0jt68SrTaOgO7NaXsboXFjwEa42Ug5lB5d5/Qdp 1AITUv0NJ51kKwhHL1dEagGeloIsGVQILmpS0MLdtitBHqZLsnJkRvtMaxo47giyBlv2ewmq tIGTlVLxHx9xkc9aVepOuiGlZaZB72c9AvZs9rKaAjgU2UfJHlB/Hr4uSk/1EY0IgMv4vnsG 1sA5gvS7A4T4euu0PqHtn2sZEWDrk5RDbw0yIb53JYdXboLFmFXKzVASfKh2ZVeXRBlQQSJi 3PBR1GzzqORlfryby7mkY857xzCI2NkIkD2eq+HhzFTfFOTdGrkCDQRUynn8ARAAwbhP45BE d/zAMBPV2dk2WwIwKRSKULElP3kXpcuiDWYQob3UODUUqClO+3aXVRndaNmZX9WbzGYexVo3 5j+CVBCGr3DlU8AL9pp3KQ3SJihWcDed1LSmUf8tS+10d6mdGxDqgnd/OWU214isvhgWZtZG MM/Xj7cx5pERIiP+jqu7PT1cibcfcEKhPjYdyV1QnLtKNGrTg/UMKaL+qkWBUI/8uBoa0HLs NH63bXsRtNAG8w6qG7iiueYZUIXKc4IHINUguqYQJVdSe+u8b2N5XNhDSEUhdlqFYraJvX6d TjxMTW5lzVG2KjztfErRNSUmu2gezbw1/CV0ztniOKDA7mkQi6UIUDRh4LxRm5mflfKiCyDQ L6P/jxHBxFv+sIgjuLrfNhIC1p3z9rvCh+idAVJgtHtYl8p6GAVrF+4xQV2zZH45tgmHo2+S JsLPjXZtWVsWANpepXnesyabWtNAV4qQB7/SfC77zZwsVX0OOY2Qc+iohmXo8U7DgXVDgl/R /5Qgfnlv0/3rOdMt6ZPy5LJr8D9LJmcP0RvX98jyoBOf06Q9QtEwJsNLCOCo2LKNL71DNjZr nXEwjUH66CXiRXDbDKprt71BiSTitkFhGGU88XCtrp8R9yArXPf4MN+wNYBjfT7K29gWTzxt 9DYQIvEf69oZD5Z5qHYGp031E90AEQEAAYkCPAQYAQIAJgIbDBYhBPrrlxGhLPR1gS8Y8oip Bk0YNWHrBQJcXf3JBQkLVerNAAoJEIipBk0YNWHrU1AP/1FOK2SBGbyhHa5vDHuf47fgLipC e0/h1E0vdSonzlhPxuZoQ47FjzG9uOhqqQG6/PqtWs/FJIyz8aGG4aV+pSA/9Ko3/2ND8MSY ZflWs7Y8Peg08Ro01GTHFITjEUgHpTpHiT6TNcZB5aZNJ8jqCtW5UlqvXXbVeSTmO70ZiVtc vUJbpvSxYmzhFfZWaXIPcNcKWL1rnmnzs67lDhMLdkYVf91aml/XtyMUlfB8Iaejzud9Ht3r C0pA9MG57pLblX7okEshxAC0+tUdY2vANWFeX0mgqRt1GSuG9XM9H/cKP1czfUV/FgaWo/Ya fM4eMhUAlL/y+/AJxxumPhBXftM4yuiktp2JMezoIMJI9fmhjfWDw7+2jVrx9ze1joLakFD1 rVAoHxVJ7ORfQ4Ni/qWbQm3T6qQkSMt4N/scNsMczibdTPxU7qtwQwIeFOOc3wEwmJ9Qe3ox TODQ0agXiWVj0OXYCHJ6MxTDswtyTGQW+nUHpKBgHGwUaR6d1kr/LK9+5LpOfRlK9VRfEu7D PGNiRkr8Abp8jHsrBqQWfUS1bAf62bq6XUel0kUCtb7qCq024aOczXYWPFpJFX+nhp4d7NeH Edq+wlC13sBSiSHC7T5yssJ+7JPa2ATLlSKhEvBsLe2TsSTTtFlA0nBclqhfJXzimiuge9qU E40lvMWBuQINBFTKimUBEADDbJ+pQ5M4QBMWkaWImRj7c598xIZ37oKM6rGaSnuB1SVb7YCr Ci2MTwQcrQscA2jm80O8VFqWk+/XsEp62dty47GVwSfdGje/3zv3VTH2KhOCKOq3oPP5ZXWY rz2d2WnTvx++o6lU7HLHDEC3NGLYNLkL1lyVxLhnhvcMxkf1EGA1DboEcMgnJrNB1pGP27ww cSfvdyPGseV+qZZa8kuViDga1oxmnYDxFKMGLxrClqHrRt8geQL1Wj5KFM5hFtGTK4da5lPn wGNd6/CINMeCT2AWZY5ySz7/tSZe5F22vPvVZGoPgQicYWdNc3ap7+7IKP86JNjmec/9RJcz jvrYjJdiqBVldXou72CtDydKVLVSKv8c2wBDJghYZitfYIaL8cTvQfUHRYTfo0n5KKSec8Vo vjDuxmdbOUBA+SkRxqmneP5OxGoZ92VusrwWCjry8HRsNdR+2T+ClDCO6Wpihu4V3CPkQwTy eCuMHPAT0ka5paTwLrnZIxsdfnjUa96T10vzmQgAxpbbiaLvgKJ8+76OPdDnhddyxd2ldYfw RkF5PEGg3mqZnYKNNBtwjvX49SAvgETQvLzQ8IKVgZS0m4z9qHHvtc1BsQnFfe+LJOFjzZr7 CrDNJMqk1JTHYsSi2JcN3vY32WMezXSQ0TzeMK4kdnclSQyp/h23GWod5QARAQABiQRbBBgB AgAmAhsCFiEE+uuXEaEs9HWBLxjyiKkGTRg1YesFAlxd/coFCQtV2mQCKcFdIAQZAQIABgUC VMqKZQAKCRB974EGqvw5DiJoEACLmuiRq9ifvOh5DyBFwRS7gvA14DsGQngmC57EzV0EFcfM XVi1jX5OtwUyUe0Az5r6lHyyHDsDsIpLKBlWrYCeLpUhRR3oy181T7UNxvujGFeTkzvLAOo6 Hs3b8Wv9ARg+7acRYkQRNY7k0GIJ6YZz149tRyRKAy/vSjsaB9Lt0NOd1wf2EQMKwRVELwJD y0AazGn+0PRP7Bua2YbtxaBmhBBDb2tPpwn8U9xdckB4Vlft9lcWNsC/18Gi9bpjd9FSbdH/ sOUI+3ToWYENeoT4IP09wn6EkgWaJS3nAUN/MOycNej2i4Yhy2wDDSKyTAnVkSSSoXk+tK91 HfqtokbDanB8daP+K5LgoiWHzjfWzsxA2jKisI4YCGjrYQzTyGOT6P6u6SEeoEx10865B/zc 8/vN50kncdjYz2naacIDEKQNZlnGLsGkpCbfmfdi3Zg4vuWKNdWr0wGUzDUcpqW0y/lUXna+ 6uyQShX5e4JD2UPuf9WAQ9HtgSAkaDd4O1I2J41sleePzZOVB3DmYgy+ECRJJ5nw3ihdxpgc y/v3lfcJaqiyCv0PF+K/gSOvwhH7CbVqARmptT7yhhxqFdaYWo2Z2ksuKyoKSRMFCXQY5oac uTmyPIT4STFyUQFeqSCWDum/NFNoSKhmItw2Td+4VSJHShRVbg39KNFPZ7mXYAkQiKkGTRg1 YesWJA/+PV3qDUtPNEGwjVvjQqHSbrBy94tu6gJvPHgGPtRDYvxnCaJsmgiC0pGB2KFRsnfl 2zBNBEWF/XwsI081jQE5UO60GKmHTputChLXpVobyuc+lroG2YhknXRBAV969SLnZR4BS/1s Gi046gOXfaKYatve8BiZr5it5Foq3FMPDNgZMit1H9Dk8rkKFfDMRf8EGS/Z+TmyEsIf99H7 TH3n7lco8qO81fSFwkh4pvo2kWRFYTC5vsIVQ+GqVUp+W1DZJHxX8LwWuF1AzUt4MUTtNAvy TXl5EgsmoY9mpNNL7ZnW65oG63nEP5KNiybvuQJzXVxR8eqzOh2Mod4nHg3PE7UCd3DvLNsn GXFRo44WyT/G2lArBtjpkut7bDm0i1nENABy2UgS+1QvdmgNu6aEZxdNthwRjUhuuvCCDMA4 rCDQYyakH2tJNQgkXkeLodBKF4bHiBbuwj0E39S9wmGgg+q4OTnAO/yhQGknle7a7G5xHBwE i0HjnLoJP5jDcoMTabZTIazXmJz3pKM11HYJ5/ZsTIf3ZRJJKIvXJpbmcAPVwTZII6XxiJdh RSSX4Mvd5pL/+5WI6NTdW6DMfigTtdd85fe6PwBNVJL2ZvBfsBJZ5rxg1TOH3KLsYBqBTgW2 glQofxhkJhDEcvjLhe3Y2BlbCWKOmvM8XS9TRt0OwUs= Message-ID: <504a4611-e45c-2034-ac9a-f6acf90e24f5@redhat.com> Date: Thu, 15 Aug 2019 17:24:35 -0400 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: <20190815074459.GN300@andariel.pipo.sk> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Thu, 15 Aug 2019 21:24:40 +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] [libvirt] [PATCH 1/2] qapi: deprecate drive-mirror and drive-backup 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 , Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org, libvir-list@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com, den@openvz.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 8/15/19 3:44 AM, Peter Krempa wrote: > On Wed, Aug 14, 2019 at 15:22:15 -0400, John Snow wrote: >> >> >> On 8/14/19 6:07 AM, Vladimir Sementsov-Ogievskiy wrote: >>> It's hard and not necessary to maintain outdated versions of these >>> commands. >>> >>> Signed-off-by: Vladimir Sementsov-Ogievskiy >>> --- >>> qemu-deprecated.texi | 4 ++++ >>> qapi/block-core.json | 4 ++++ >>> qapi/transaction.json | 2 +- >>> blockdev.c | 10 ++++++++++ >>> 4 files changed, 19 insertions(+), 1 deletion(-) >>> >>> diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi >>> index fff07bb2a3..2753fafd0b 100644 >>> --- a/qemu-deprecated.texi >>> +++ b/qemu-deprecated.texi >>> @@ -179,6 +179,10 @@ and accurate ``query-qmp-schema'' command. >>> Character devices creating sockets in client mode should not specify >>> the 'wait' field, which is only applicable to sockets in server mode >>> >>> +@subsection drive-mirror, drive-backup and drive-backup transaction action (since 4.2) >>> + >>> +Use blockdev-mirror and blockdev-backup instead. >>> + >>> @section Human Monitor Protocol (HMP) commands >>> >>> @subsection The hub_id parameter of 'hostfwd_add' / 'hostfwd_remove' (since 3.1) > > [...] > >>> @@ -3831,6 +3838,9 @@ void qmp_drive_mirror(DriveMirror *arg, Error **errp) >>> const char *format = arg->format; >>> int ret; >>> >>> + warn_report("drive-mirror command is deprecated and will disappear in " >>> + "future. Use blockdev-mirror instead"); >>> + >>> bs = qmp_get_root_bs(arg->device, errp); >>> if (!bs) { >>> return; >>> >> >> Hm! >> >> I wonder if this is ever-so-slightly too soon for our friends over at >> the libvirt project. >> >> I don't think they have fully moved away from the non-blockdev >> interfaces *just yet*, and I might encourage seeing the first full >> libvirt release that does support and use it before we start the >> deprecation clock. >> >> (Juuuust in case.) >> >> That's just me being very, very cautious though. >> >> Peter Krempa, how do you feel about this? > > Thanks for the heads up! > You're welcome! > Currently libvirt does not use 'drive-backup' at all so that one can be > deprecated immediately. > > In case of 'drive-mirror' the situation is a bit more complex: > > Libvirt uses 'drive-mirror' currently in the following places > > 1) virDomainBlockCopy API > With blockdev integration enabled this will go away. Pathces are being > reviewed: > > https://www.redhat.com/archives/libvir-list/2019-August/msg00295.html > > 2) VM migration with non-shared storage > Currently uses 'drive-mirror' in most cases but there is pre-existing > integration for blockdev-mirror for nbd+tls. I need to make sure that > the blockdev version will be used unconditionally once the integration > is enabled. This is a TODO. > > There is also one gotcha. In case when an 'sd' card device is used for > the VM, libvirt disables all of blockdev, because SD cards can't be > expressed with blockdev. There's too many code paths which would need > checking to be worth it. To be fair, I'm not even sure when a sd card > can be emulated by qemu as all of my basic tests failed and I did not > care more. > > For libvirt to enable blockdev there's one more part missing and that's > snapshot integration. I'm currently testing patches to integrate it with > external snapshots, which should be posted soon. > > I also found a bug in qemu, which prevents creation of internal > snapshots when -blockdev is used: > > When savevm HMP command is used (via QMP->HMP bridge) qemu invokes > save_snapshot(), which calls bdrv_all_can_snapshot(). That function uses > bdrv_next() to iterate all nodes which correspond to a block backend > first, but then also iterates any other node which is monitor-owned. > > Since with blockdev all nodes including the ones for the 'file' protocol > are monitor-owned, and 'file' does not support snapshots that check > fails. A simple hack of skipping the second part in bdrv_next() allows > to do a snapshot actually. Kevin told me that the idea is that also > non-attached nodes should be considered for internal snapshod which is > okay in my opinion, but given how the snapshot works for the files > attached to backeds (and also in pre-blockdev use) only the top level of > a chain should ever be considered for snapshot. > > So the summary is, that I'm pretty hopeful that we should be able to get > rid of all reasonable uses of drive-mirror very soon after I finish > snapshot integration. The only question is how much > we care about SD card users being able to do a drive-mirror in the > future. > OK. It sounds like we should hold off on deprecating these for now because it's not certain which libvirt release will no longer need them, but it sounds like it's hopefully not far off. --js