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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 BD4A2C31E46 for ; Wed, 12 Jun 2019 22:30:51 +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 93DA3208C2 for ; Wed, 12 Jun 2019 22:30:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 93DA3208C2 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]:35524 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hbBlX-00005H-BK for qemu-devel@archiver.kernel.org; Wed, 12 Jun 2019 18:30:50 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45654) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hbBSE-0007qR-At for qemu-devel@nongnu.org; Wed, 12 Jun 2019 18:10:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hbBSC-0007ks-UG for qemu-devel@nongnu.org; Wed, 12 Jun 2019 18:10:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58820) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hbBS9-0007id-VX; Wed, 12 Jun 2019 18:10:46 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 3E9518F927; Wed, 12 Jun 2019 22:10:45 +0000 (UTC) Received: from localhost (unknown [10.40.205.72]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C4B8B60BF0; Wed, 12 Jun 2019 22:10:44 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Thu, 13 Jun 2019 00:09:37 +0200 Message-Id: <20190612221004.2317-16-mreitz@redhat.com> In-Reply-To: <20190612221004.2317-1-mreitz@redhat.com> References: <20190612221004.2317-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Wed, 12 Jun 2019 22:10:45 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v5 15/42] block: Re-evaluate backing file handling in reopen 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Reopening a node's backing child needs a bit of special handling because the "backing" child has different defaults than all other children (among other things). Adding filter support here is a bit more difficult than just using the child access functions. In fact, we often have to directly use bs->backing because these functions are about the "backing" child (which may or may not be the COW backing file). Signed-off-by: Max Reitz --- block.c | 36 +++++++++++++++++++++++++++++------- 1 file changed, 29 insertions(+), 7 deletions(-) diff --git a/block.c b/block.c index 505b3e9a01..db2759c10d 100644 --- a/block.c +++ b/block.c @@ -3542,17 +3542,39 @@ static int bdrv_reopen_parse_backing(BDRVReopenSt= ate *reopen_state, } } =20 + /* + * Ensure that @bs can really handle backing files, because we are + * about to give it one (or swap the existing one) + */ + if (bs->drv->is_filter) { + /* Filters always have a file or a backing child */ + if (!bs->backing) { + error_setg(errp, "'%s' is a %s filter node that does not sup= port a " + "backing child", bs->node_name, bs->drv->format_n= ame); + return -EINVAL; + } + } else if (!bs->drv->supports_backing) { + error_setg(errp, "Driver '%s' of node '%s' does not support back= ing " + "files", bs->drv->format_name, bs->node_name); + return -EINVAL; + } + /* * Find the "actual" backing file by skipping all links that point * to an implicit node, if any (e.g. a commit filter node). + * We cannot use any of the bdrv_skip_*() functions here because + * those return the first explicit node, while we are looking for + * its overlay here. */ overlay_bs =3D bs; - while (backing_bs(overlay_bs) && backing_bs(overlay_bs)->implicit) { - overlay_bs =3D backing_bs(overlay_bs); + while (bdrv_filtered_bs(overlay_bs) && + bdrv_filtered_bs(overlay_bs)->implicit) + { + overlay_bs =3D bdrv_filtered_bs(overlay_bs); } =20 /* If we want to replace the backing file we need some extra checks = */ - if (new_backing_bs !=3D backing_bs(overlay_bs)) { + if (new_backing_bs !=3D bdrv_filtered_bs(overlay_bs)) { /* Check for implicit nodes between bs and its backing file */ if (bs !=3D overlay_bs) { error_setg(errp, "Cannot change backing link if '%s' has " @@ -3560,8 +3582,8 @@ static int bdrv_reopen_parse_backing(BDRVReopenStat= e *reopen_state, return -EPERM; } /* Check if the backing link that we want to replace is frozen *= / - if (bdrv_is_backing_chain_frozen(overlay_bs, backing_bs(overlay_= bs), - errp)) { + if (bdrv_is_backing_chain_frozen(overlay_bs, + child_bs(overlay_bs->backing), = errp)) { return -EPERM; } reopen_state->replace_backing_bs =3D true; @@ -3712,7 +3734,7 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_sta= te, BlockReopenQueue *queue, * its metadata. Otherwise the 'backing' option can be omitted. */ if (drv->supports_backing && reopen_state->backing_missing && - (backing_bs(reopen_state->bs) || reopen_state->bs->backing_file[= 0])) { + (reopen_state->bs->backing || reopen_state->bs->backing_file[0])= ) { error_setg(errp, "backing is missing for '%s'", reopen_state->bs->node_name); ret =3D -EINVAL; @@ -3857,7 +3879,7 @@ void bdrv_reopen_commit(BDRVReopenState *reopen_sta= te) * from bdrv_set_backing_hd()) has the new values. */ if (reopen_state->replace_backing_bs) { - BlockDriverState *old_backing_bs =3D backing_bs(bs); + BlockDriverState *old_backing_bs =3D child_bs(bs->backing); assert(!old_backing_bs || !old_backing_bs->implicit); /* Abort the permission update on the backing bs we're detaching= */ if (old_backing_bs) { --=20 2.21.0