From nobody Mon Feb 9 03:13:16 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1582022188422391.7822401247979; Tue, 18 Feb 2020 02:36:28 -0800 (PST) Received: from localhost ([::1]:60548 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j40Et-00031w-DC for importer@patchew.org; Tue, 18 Feb 2020 05:36:27 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:51968) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j40Dc-0000wy-1R for qemu-devel@nongnu.org; Tue, 18 Feb 2020 05:35:09 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j40Da-0007JH-Sp for qemu-devel@nongnu.org; Tue, 18 Feb 2020 05:35:07 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:34065 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j40Da-0007Ix-OA for qemu-devel@nongnu.org; Tue, 18 Feb 2020 05:35:06 -0500 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-35-EGNAsc17NEa69aQSzw8GXA-1; Tue, 18 Feb 2020 05:35:01 -0500 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 6797E18A6EDE; Tue, 18 Feb 2020 10:35:00 +0000 (UTC) Received: from localhost (unknown [10.36.118.17]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D70B790F6E; Tue, 18 Feb 2020 10:34:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582022106; 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=TYrnGQvnIp4hR7+02aVeNf2B9V4JyaHfAzZh/E13Tzk=; b=eKvmoYjRSnvEuKlvZ+GXsDGDMN84zutNkpZ+lHYsdKP5a0gNq47EW6qxPbtuQehYIt1V47 sM9PSHPJvzticlkCPRJlE0GGSvsTPr6z1ztoRgGqxMuTulyzSDceR+0P90WUNedYx442pd uDlNV57M4ps+fpuUIFLrW3A8C+wEv5Y= From: Max Reitz To: qemu-block@nongnu.org Subject: [PATCH v4 01/19] blockdev: Allow external snapshots everywhere Date: Tue, 18 Feb 2020 11:34:36 +0100 Message-Id: <20200218103454.296704-2-mreitz@redhat.com> In-Reply-To: <20200218103454.296704-1-mreitz@redhat.com> References: <20200218103454.296704-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-MC-Unique: EGNAsc17NEa69aQSzw8GXA-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 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-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" There is no good reason why we would allow external snapshots only on the first non-filter node in a chain. Parent BDSs should not care whether their child is replaced by a snapshot. (If they do care, they should announce that via freezing the chain, which is checked in bdrv_append() through bdrv_set_backing_hd().) Before we had bdrv_is_first_non_filter() here (since 212a5a8f095), there was a special function bdrv_check_ext_snapshot() that allowed snapshots by default, but block drivers could override this. Only blkverify did so, however. It is not clear to me why blkverify would do so; maybe just so that the testee block driver would not be replaced. The introducing commit f6186f49e2c does not explain why. Maybe because 08b24cfe376 would have been the correct solution? (Which adds a .supports_backing check.) Signed-off-by: Max Reitz Reviewed-by: Vladimir Sementsov-Ogievskiy --- blockdev.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/blockdev.c b/blockdev.c index 43d931fd79..1745d740ec 100644 --- a/blockdev.c +++ b/blockdev.c @@ -1592,11 +1592,6 @@ static void external_snapshot_prepare(BlkActionState= *common, } } =20 - if (!bdrv_is_first_non_filter(state->old_bs)) { - error_setg(errp, QERR_FEATURE_DISABLED, "snapshot"); - goto out; - } - if (action->type =3D=3D TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC= ) { BlockdevSnapshotSync *s =3D action->u.blockdev_snapshot_sync.data; const char *format =3D s->has_format ? s->format : "qcow2"; --=20 2.24.1