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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 4C9D2C77B7A for ; Wed, 17 May 2023 16:53:59 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pzKNN-00044n-1a; Wed, 17 May 2023 12:51:45 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pzKNI-00040W-FQ for qemu-devel@nongnu.org; Wed, 17 May 2023 12:51:40 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pzKNG-0001S3-Js for qemu-devel@nongnu.org; Wed, 17 May 2023 12:51:40 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1684342296; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Rr1TucJqp+IIm096jK8/R7QHSZpWnM6VF3aeyatA+MI=; b=g+FgdexKY6ubV2htbVm/mHb2GBP/HqobvEqd+yNLd0dCN9nYuYD1KfKjWCpKaojlx6J40d 3UCHfcjOL2x4KLtfcu65gTINBsvAAoEpBl5o+UWJ+knFaHkCY0gAjWybxffeiRf+ZwAvLN iIUViF02bQByO5wpBzVsQiZ7Q/ikdHg= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-232-MuELR3u2Pcmthli_9v3r9w-1; Wed, 17 May 2023 12:51:33 -0400 X-MC-Unique: MuELR3u2Pcmthli_9v3r9w-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 2593D29AB3F0; Wed, 17 May 2023 16:51:33 +0000 (UTC) Received: from merkur.fritz.box (unknown [10.39.194.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6D4B340C6EC4; Wed, 17 May 2023 16:51:32 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, richard.henderson@linaro.org, qemu-devel@nongnu.org Subject: [PULL 10/18] qcow2: Unlock the graph in qcow2_do_open() where necessary Date: Wed, 17 May 2023 18:51:08 +0200 Message-Id: <20230517165116.475123-11-kwolf@redhat.com> In-Reply-To: <20230517165116.475123-1-kwolf@redhat.com> References: <20230517165116.475123-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com 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_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org qcow2_do_open() calls a few no_co_wrappers that wrap functions taking the graph lock internally as a writer. Therefore, it can't hold the reader lock across these calls, it causes deadlocks. Drop the lock temporarily around the calls. Signed-off-by: Kevin Wolf Message-Id: <20230510203601.418015-4-kwolf@redhat.com> Reviewed-by: Eric Blake Signed-off-by: Kevin Wolf --- block/qcow2.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/block/qcow2.c b/block/qcow2.c index 73f36447f9..b00b4e7575 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -1619,9 +1619,11 @@ qcow2_do_open(BlockDriverState *bs, QDict *options, int flags, if (open_data_file) { /* Open external data file */ + bdrv_graph_co_rdunlock(); s->data_file = bdrv_co_open_child(NULL, options, "data-file", bs, &child_of_bds, BDRV_CHILD_DATA, true, errp); + bdrv_graph_co_rdlock(); if (*errp) { ret = -EINVAL; goto fail; @@ -1629,10 +1631,12 @@ qcow2_do_open(BlockDriverState *bs, QDict *options, int flags, if (s->incompatible_features & QCOW2_INCOMPAT_DATA_FILE) { if (!s->data_file && s->image_data_file) { + bdrv_graph_co_rdunlock(); s->data_file = bdrv_co_open_child(s->image_data_file, options, "data-file", bs, &child_of_bds, BDRV_CHILD_DATA, false, errp); + bdrv_graph_co_rdlock(); if (!s->data_file) { ret = -EINVAL; goto fail; @@ -1857,7 +1861,9 @@ qcow2_do_open(BlockDriverState *bs, QDict *options, int flags, fail: g_free(s->image_data_file); if (open_data_file && has_data_file(bs)) { + bdrv_graph_co_rdunlock(); bdrv_unref_child(bs, s->data_file); + bdrv_graph_co_rdlock(); s->data_file = NULL; } g_free(s->unknown_header_fields); -- 2.40.1