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=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,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 58A52C433B4 for ; Fri, 30 Apr 2021 11:45:52 +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 F0D08613FA for ; Fri, 30 Apr 2021 11:45:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F0D08613FA 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]:35452 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lcRag-0008D1-UR for qemu-devel@archiver.kernel.org; Fri, 30 Apr 2021 07:45:50 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37028) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lcQly-0005Dm-Tj for qemu-devel@nongnu.org; Fri, 30 Apr 2021 06:53:26 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:35449) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lcQlp-0002uA-Gj for qemu-devel@nongnu.org; Fri, 30 Apr 2021 06:53:26 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619779989; 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=uGG0fmrhfcOATjuUJX1bVZwjwTj+jLWrAd4mWW7jh2o=; b=HElPVsXTSceg0gcIwmD1Mxp5+teRKs3ZdLxJcKd5fdqaoBQkigKjNw1ciOBAfc/K95vTmY H/rLM4HDO2ncL+PlPPTei17js7xPF0bk34zS4SXjXH38sckoUpp/zsDYDVkm/pUBKufg6M lH3+svDMOb/xK6GM75cusmHID2Dblas= 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-517-Ga2-SRgDPa6mPhjvvRhrOw-1; Fri, 30 Apr 2021 06:53:01 -0400 X-MC-Unique: Ga2-SRgDPa6mPhjvvRhrOw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D14DD108597F; Fri, 30 Apr 2021 10:52:59 +0000 (UTC) Received: from merkur.fritz.box (ovpn-114-197.ams2.redhat.com [10.36.114.197]) by smtp.corp.redhat.com (Postfix) with ESMTP id 726A767889; Fri, 30 Apr 2021 10:52:29 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PULL 16/39] block: add bdrv_replace_child_safe() transaction action Date: Fri, 30 Apr 2021 12:51:24 +0200 Message-Id: <20210430105147.125840-17-kwolf@redhat.com> In-Reply-To: <20210430105147.125840-1-kwolf@redhat.com> References: <20210430105147.125840-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 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-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" Received-SPF: pass client-ip=216.205.24.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.22, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=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: Vladimir Sementsov-Ogievskiy To be used in the following commit. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Kevin Wolf Message-Id: <20210428151804.439460-17-vsementsov@virtuozzo.com> Signed-off-by: Kevin Wolf --- block.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) diff --git a/block.c b/block.c index 98b7bc179c..a5305662dc 100644 --- a/block.c +++ b/block.c @@ -83,6 +83,9 @@ static BlockDriverState *bdrv_open_inherit(const char *filename, BdrvChildRole child_role, Error **errp); +static void bdrv_replace_child_noperm(BdrvChild *child, + BlockDriverState *new_bs); + static int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue, Error **errp); static void bdrv_reopen_commit(BDRVReopenState *reopen_state); @@ -2237,6 +2240,57 @@ static int bdrv_drv_set_perm(BlockDriverState *bs, uint64_t perm, return 0; } +typedef struct BdrvReplaceChildState { + BdrvChild *child; + BlockDriverState *old_bs; +} BdrvReplaceChildState; + +static void bdrv_replace_child_commit(void *opaque) +{ + BdrvReplaceChildState *s = opaque; + + bdrv_unref(s->old_bs); +} + +static void bdrv_replace_child_abort(void *opaque) +{ + BdrvReplaceChildState *s = opaque; + BlockDriverState *new_bs = s->child->bs; + + /* old_bs reference is transparently moved from @s to @s->child */ + bdrv_replace_child_noperm(s->child, s->old_bs); + bdrv_unref(new_bs); +} + +static TransactionActionDrv bdrv_replace_child_drv = { + .commit = bdrv_replace_child_commit, + .abort = bdrv_replace_child_abort, + .clean = g_free, +}; + +/* + * bdrv_replace_child_safe + * + * Note: real unref of old_bs is done only on commit. + */ +__attribute__((unused)) +static void bdrv_replace_child_safe(BdrvChild *child, BlockDriverState *new_bs, + Transaction *tran) +{ + BdrvReplaceChildState *s = g_new(BdrvReplaceChildState, 1); + *s = (BdrvReplaceChildState) { + .child = child, + .old_bs = child->bs, + }; + tran_add(tran, &bdrv_replace_child_drv, s); + + if (new_bs) { + bdrv_ref(new_bs); + } + bdrv_replace_child_noperm(child, new_bs); + /* old_bs reference is transparently moved from @child to @s */ +} + /* * Check whether permissions on this node can be changed in a way that * @cumulative_perms and @cumulative_shared_perms are the new cumulative -- 2.30.2