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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 6A6A0C4363A for ; Wed, 21 Oct 2020 10:49:34 +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 7BF032080C for ; Wed, 21 Oct 2020 10:49:33 +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="c5fOgvOs" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7BF032080C 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]:48914 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kVBgS-0004CG-0k for qemu-devel@archiver.kernel.org; Wed, 21 Oct 2020 06:49:32 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48952) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kVBfa-0003ao-1Z for qemu-devel@nongnu.org; Wed, 21 Oct 2020 06:48:38 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:30374) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kVBfX-0000MZ-Sr for qemu-devel@nongnu.org; Wed, 21 Oct 2020 06:48:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1603277314; 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: in-reply-to:in-reply-to:references:references; bh=EP0zm6wg0wV1qgGLkFJ0ieEECxTVLKe9kgdr3XbICg8=; b=c5fOgvOsGz9N74tjP8A7B1Gg132zB7kO5sjw1zc3X6xdswJjcVJoI2jhMLf454MPbz8PR3 9PY8euYP0G14kY7bjHMIam1ntv1I99i3X4v1BqrbrqBpjOLIQP+RWzXT8vCjuL2Gy5d5XV ol/3f+ORg68elI9hXO5Lej5UkIjJEX0= 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-532-2xhvh3BzPDi-S-eZjNfH1g-1; Wed, 21 Oct 2020 06:48:31 -0400 X-MC-Unique: 2xhvh3BzPDi-S-eZjNfH1g-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id 015F9106C0F7; Wed, 21 Oct 2020 10:48:29 +0000 (UTC) Received: from merkur.fritz.box (ovpn-112-150.ams2.redhat.com [10.36.112.150]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C96E710013C1; Wed, 21 Oct 2020 10:48:27 +0000 (UTC) Date: Wed, 21 Oct 2020 12:48:26 +0200 From: Kevin Wolf To: Alberto Garcia Subject: Re: Plans to bring QMP 'x-blockdev-reopen' out of experimental? Message-ID: <20201021104826.GA8958@merkur.fritz.box> References: <20201006091001.GA64583@paraplu> <20201020082333.GB4452@merkur.fritz.box> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=63.128.21.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/20 22:12:28 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, 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=ham 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: mreitz@redhat.com, qemu-devel@nongnu.org, qemu-block@nongnu.org, Kashyap Chamarthy Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 20.10.2020 um 13:53 hat Alberto Garcia geschrieben: > On Tue 20 Oct 2020 10:23:33 AM CEST, Kevin Wolf wrote: > >> > https://lists.gnu.org/archive/html/qemu-block/2020-02/msg00601.html > >> > >> I forgot to add, we still don't support changing bs->file with this > >> command, so I guess that would be one blocker? > >> > >> There's no other way of inserting filter nodes, or is there? > > > > Not that I'm aware of. > > > > So yes, changing bs->file is the one thing I had in mind for > > implementing before we mark it stable. > > Note that you can still open a new bs with a different bs->file and > replace the original one (as long as the original one is the backing > file of an existing bs, that is :)). You can't open the same image twice, so this won't always work. > > I'm not entirely sure if we should make some restrictions or allow > > arbitrary changes. If it's only about filters, we could check that the > > node returned by bdrv_skip_filters() stays the same. This would be > > almost certainly safe (if the chain is not frozen, of course). > > > > If people want to dynamically insert non-filters (maybe quorum?), it > > might be more restrictive than necessary, though. > > You mean replacing bs->file with a Quorum node? Quorum itself does not > use bs->file, it has the 'children' attribute. Yes, replaying bs->file with a Quorum node that has the old bs->file as one of its children. Or removing a Quorum node so that one of it's children replaces it. But this is probably not a very important use case, so I think the restriction is not a problem. Lifting restrictions later is easier than adding new ones. Kevin