From nobody Mon Feb 9 03:13:22 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; 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=pass(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1683751036; cv=none; d=zohomail.com; s=zohoarc; b=ELGagWQg0amfSPYgBuxIJZvAFg0VRq8n4pHod8UEn+n/hKDdOTC/u6ucu2bUjM4DefnCxQDNbV5a5cuQGO0s5iAb9xsoSPDZut3Q2SNPy0vvbU2EvBzZyHNuSFXSAAVYv80DsdkMmGUCuOlcAstqj/5/zfF1LdYSVOyBe9pwpT4= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1683751036; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=EcIuTYtOPwDAHB/h3j6Y0xZc3CIugRqzwgLuAKQ13KY=; b=TYOO6Cx7hm4JnUEBPQJ/pxV+Ee7Gg5ladTtCgCeqaXb5wBsQfj7hZq/Ehs0rFsuqUG+qyI2m4zpLpHQjTRMZ8c4fkkfvjP21HzPbWdSZujsuIFM9uxlaMquVoeP+fzwyRoZq7zvHFPXr0Meq4B5Zagb17n8NXNOH7KVNYVclknY= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; 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=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1683751036180615.0742174975694; Wed, 10 May 2023 13:37:16 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pwqYA-0005Ez-El; Wed, 10 May 2023 16:36:38 -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 1pwqY7-0005EC-GK for qemu-devel@nongnu.org; Wed, 10 May 2023 16:36:35 -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 1pwqY5-0003Ma-BC for qemu-devel@nongnu.org; Wed, 10 May 2023 16:36:35 -0400 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-580-szlSdqGOOx-haVsgKAOWuw-1; Wed, 10 May 2023 16:36:26 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1D0E2381D1EA; Wed, 10 May 2023 20:36:26 +0000 (UTC) Received: from merkur.fritz.box (unknown [10.39.194.148]) by smtp.corp.redhat.com (Postfix) with ESMTP id DF3261121314; Wed, 10 May 2023 20:36:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1683750992; 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=EcIuTYtOPwDAHB/h3j6Y0xZc3CIugRqzwgLuAKQ13KY=; b=VLqx2Si7LSmWtQyhXQRKzezIUo9AQ+9HghQjpRHnrtvW+zb+Ljucaf70A7toSV70W8knGp ztgkjEIbWVoQdnaJBdrE4wpTx3UPbXPlcB4cklLYWf7cAXTPTU+g+xJCEuyt8st+4mHcXV brVDMi501ipUwtCVO2BfYcrYoA8vaUs= X-MC-Unique: szlSdqGOOx-haVsgKAOWuw-1 From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, hreitz@redhat.com, stefanha@redhat.com, f.ebner@proxmox.com, qemu-devel@nongnu.org Subject: [PATCH 3/8] qcow2: Unlock the graph in qcow2_do_open() where necessary Date: Wed, 10 May 2023 22:35:56 +0200 Message-Id: <20230510203601.418015-4-kwolf@redhat.com> In-Reply-To: <20230510203601.418015-1-kwolf@redhat.com> References: <20230510203601.418015-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 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; 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+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1683751037339100001 Content-Type: text/plain; charset="utf-8" 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 Reviewed-by: Eric Blake --- 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, =20 if (open_data_file) { /* Open external data file */ + bdrv_graph_co_rdunlock(); s->data_file =3D bdrv_co_open_child(NULL, options, "data-file", bs, &child_of_bds, BDRV_CHILD_DATA, true, errp); + bdrv_graph_co_rdlock(); if (*errp) { ret =3D -EINVAL; goto fail; @@ -1629,10 +1631,12 @@ qcow2_do_open(BlockDriverState *bs, QDict *options,= int flags, =20 if (s->incompatible_features & QCOW2_INCOMPAT_DATA_FILE) { if (!s->data_file && s->image_data_file) { + bdrv_graph_co_rdunlock(); s->data_file =3D bdrv_co_open_child(s->image_data_file, op= tions, "data-file", bs, &child_of_bds, BDRV_CHILD_DATA, false, = errp); + bdrv_graph_co_rdlock(); if (!s->data_file) { ret =3D -EINVAL; goto fail; @@ -1857,7 +1861,9 @@ qcow2_do_open(BlockDriverState *bs, QDict *options, i= nt 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 =3D NULL; } g_free(s->unknown_header_fields); --=20 2.40.1