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=-9.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 1992AC2D0A7 for ; Mon, 7 Sep 2020 11:20:54 +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 AEC5921473 for ; Mon, 7 Sep 2020 11:20:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="MJB0Sq3N" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AEC5921473 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]:51626 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kFFCe-00069r-Pl for qemu-devel@archiver.kernel.org; Mon, 07 Sep 2020 07:20:52 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59072) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kFF2R-0002ki-QL for qemu-devel@nongnu.org; Mon, 07 Sep 2020 07:10:19 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:60633 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kFF2P-0007xl-Ly for qemu-devel@nongnu.org; Mon, 07 Sep 2020 07:10:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1599477016; 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=mPSXlbRvr/dZqDhN92G7pld69HEiKeDJn+Y200fT8DU=; b=MJB0Sq3NOXcI6e7JErF71achsUtTH+G+yw6fnj2iS4C/z4lu0ARwmZLDIkGXM0625kVi2T X38eUq98yXgMhy5sHvfK6FSgDY9YXAJ0KdkD1Vj88STtp1gfiAOdIed+ATFeQ+N2NowP7n vIIUgA8/fhTlT8wOAgWpxJ4Dt2zQs3Y= 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-162-1XDjibZDPLyn9qmjbbOa-Q-1; Mon, 07 Sep 2020 07:10:12 -0400 X-MC-Unique: 1XDjibZDPLyn9qmjbbOa-Q-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C5162802B70; Mon, 7 Sep 2020 11:10:11 +0000 (UTC) Received: from linux.fritz.box.com (ovpn-114-154.ams2.redhat.com [10.36.114.154]) by smtp.corp.redhat.com (Postfix) with ESMTP id D0BEC9CBA; Mon, 7 Sep 2020 11:10:10 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PULL 21/64] block: Include filters when freezing backing chain Date: Mon, 7 Sep 2020 13:08:53 +0200 Message-Id: <20200907110936.261684-22-kwolf@redhat.com> In-Reply-To: <20200907110936.261684-1-kwolf@redhat.com> References: <20200907110936.261684-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0.002 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=205.139.110.120; envelope-from=kwolf@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/07 03:19:10 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.1, 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_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Max Reitz In order to make filters work in backing chains, the associated functions must be able to deal with them and freeze both COW and filter child links. While at it, add some comments that note which functions require their caller to ensure that a given child link is not frozen, and how the callers do so. Signed-off-by: Max Reitz Reviewed-by: Andrey Shinkevich Reviewed-by: Kevin Wolf --- block.c | 60 +++++++++++++++++++++++++++++++++++++-------------------- 1 file changed, 39 insertions(+), 21 deletions(-) diff --git a/block.c b/block.c index e8d09d46ec..edef6273b8 100644 --- a/block.c +++ b/block.c @@ -2612,12 +2612,15 @@ static void bdrv_replace_child_noperm(BdrvChild *child, * If @new_bs is not NULL, bdrv_check_perm() must be called beforehand, as this * function uses bdrv_set_perm() to update the permissions according to the new * reference that @new_bs gets. + * + * Callers must ensure that child->frozen is false. */ static void bdrv_replace_child(BdrvChild *child, BlockDriverState *new_bs) { BlockDriverState *old_bs = child->bs; uint64_t perm, shared_perm; + /* Asserts that child->frozen == false */ bdrv_replace_child_noperm(child, new_bs); /* @@ -2778,6 +2781,7 @@ static void bdrv_detach_child(BdrvChild *child) g_free(child); } +/* Callers must ensure that child->frozen is false. */ void bdrv_root_unref_child(BdrvChild *child) { BlockDriverState *child_bs; @@ -2815,6 +2819,7 @@ static void bdrv_unset_inherits_from(BlockDriverState *root, BdrvChild *child) } } +/* Callers must ensure that child->frozen is false. */ void bdrv_unref_child(BlockDriverState *parent, BdrvChild *child) { if (child == NULL) { @@ -2881,6 +2886,7 @@ void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd, } if (bs->backing) { + /* Cannot be frozen, we checked that above */ bdrv_unref_child(bs, bs->backing); bs->backing = NULL; } @@ -4387,6 +4393,7 @@ static void bdrv_close(BlockDriverState *bs) if (bs->drv) { if (bs->drv->bdrv_close) { + /* Must unfreeze all children, so bdrv_unref_child() works */ bs->drv->bdrv_close(bs); } bs->drv = NULL; @@ -4762,20 +4769,22 @@ BlockDriverState *bdrv_find_base(BlockDriverState *bs) } /* - * Return true if at least one of the backing links between @bs and - * @base is frozen. @errp is set if that's the case. + * Return true if at least one of the COW (backing) and filter links + * between @bs and @base is frozen. @errp is set if that's the case. * @base must be reachable from @bs, or NULL. */ bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base, Error **errp) { BlockDriverState *i; + BdrvChild *child; - for (i = bs; i != base; i = backing_bs(i)) { - if (i->backing && i->backing->frozen) { + for (i = bs; i != base; i = child_bs(child)) { + child = bdrv_filter_or_cow_child(i); + + if (child && child->frozen) { error_setg(errp, "Cannot change '%s' link from '%s' to '%s'", - i->backing->name, i->node_name, - backing_bs(i)->node_name); + child->name, i->node_name, child->bs->node_name); return true; } } @@ -4784,7 +4793,7 @@ bool bdrv_is_backing_chain_frozen(BlockDriverState *bs, BlockDriverState *base, } /* - * Freeze all backing links between @bs and @base. + * Freeze all COW (backing) and filter links between @bs and @base. * If any of the links is already frozen the operation is aborted and * none of the links are modified. * @base must be reachable from @bs, or NULL. @@ -4794,22 +4803,25 @@ int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base, Error **errp) { BlockDriverState *i; + BdrvChild *child; if (bdrv_is_backing_chain_frozen(bs, base, errp)) { return -EPERM; } - for (i = bs; i != base; i = backing_bs(i)) { - if (i->backing && backing_bs(i)->never_freeze) { + for (i = bs; i != base; i = child_bs(child)) { + child = bdrv_filter_or_cow_child(i); + if (child && child->bs->never_freeze) { error_setg(errp, "Cannot freeze '%s' link to '%s'", - i->backing->name, backing_bs(i)->node_name); + child->name, child->bs->node_name); return -EPERM; } } - for (i = bs; i != base; i = backing_bs(i)) { - if (i->backing) { - i->backing->frozen = true; + for (i = bs; i != base; i = child_bs(child)) { + child = bdrv_filter_or_cow_child(i); + if (child) { + child->frozen = true; } } @@ -4817,18 +4829,21 @@ int bdrv_freeze_backing_chain(BlockDriverState *bs, BlockDriverState *base, } /* - * Unfreeze all backing links between @bs and @base. The caller must - * ensure that all links are frozen before using this function. + * Unfreeze all COW (backing) and filter links between @bs and @base. + * The caller must ensure that all links are frozen before using this + * function. * @base must be reachable from @bs, or NULL. */ void bdrv_unfreeze_backing_chain(BlockDriverState *bs, BlockDriverState *base) { BlockDriverState *i; + BdrvChild *child; - for (i = bs; i != base; i = backing_bs(i)) { - if (i->backing) { - assert(i->backing->frozen); - i->backing->frozen = false; + for (i = bs; i != base; i = child_bs(child)) { + child = bdrv_filter_or_cow_child(i); + if (child) { + assert(child->frozen); + child->frozen = false; } } } @@ -4931,8 +4946,11 @@ int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base, } } - /* Do the actual switch in the in-memory graph. - * Completes bdrv_check_update_perm() transaction internally. */ + /* + * Do the actual switch in the in-memory graph. + * Completes bdrv_check_update_perm() transaction internally. + * c->frozen is false, we have checked that above. + */ bdrv_ref(base); bdrv_replace_child(c, base); bdrv_unref(top); -- 2.25.4