From patchwork Wed May 10 20:35:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 13237233 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 E4CA8C77B7C for ; Wed, 10 May 2023 20:37:11 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pwqXz-00059X-BJ; Wed, 10 May 2023 16:36:27 -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 1pwqXx-000599-TD for qemu-devel@nongnu.org; Wed, 10 May 2023 16:36:25 -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 1pwqXw-0003JI-1Z for qemu-devel@nongnu.org; Wed, 10 May 2023 16:36:25 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1683750982; 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; bh=OvcCae/Y6jXwfmYluHzgeaiEKBYZt2MG3anOdbKTeho=; b=DriHNJYrik6blihEbqf5IKYEzblK1C7uAao9+iD8fUeY/0GXP42EBTv7Y/NhONyxgYKR99 bFP+Jc3bogcMQXTWqbVBCuM/rspYlZLiAo3MV9+eyVvoktW6ljRwqF1B/SRkvJDreymSrG jDddowXXqNoYM1LZkhEq2hHtyTlp2Eg= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-540-okP30ejbNS2fmpU6B4JTCg-1; Wed, 10 May 2023 16:36:21 -0400 X-MC-Unique: okP30ejbNS2fmpU6B4JTCg-1 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 BC88A80B2BB; Wed, 10 May 2023 20:36:20 +0000 (UTC) Received: from merkur.fritz.box (unknown [10.39.194.148]) by smtp.corp.redhat.com (Postfix) with ESMTP id 345231121314; Wed, 10 May 2023 20:36:19 +0000 (UTC) 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 0/8] block: Honour graph read lock even in the main thread Date: Wed, 10 May 2023 22:35:53 +0200 Message-Id: <20230510203601.418015-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 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=ham 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 Fiona asked why it's correct that bdrv_graph_co_rd_lock/unlock() do nothing if qemu_in_main_thread() returns true. As far as I can tell, it's not correct. The coroutine can yield while it believes to have the lock, and then the main loop can call some code that takes a write lock without waiting for the coroutine to finish. So this series - or more specifically the last patch - fixes this problem by enabling the locking even in the main thread. The patches before this are fixes for bugs that we hadn't discovered while they were only triggered with iothreads, and which are necessary so that all test cases still pass after the final patch. Kevin Wolf (8): block: Call .bdrv_co_create(_opts) unlocked block/export: Fix null pointer dereference in error path qcow2: Unlock the graph in qcow2_do_open() where necessary qemu-img: Take graph lock more selectively test-bdrv-drain: Take graph lock more selectively test-bdrv-drain: Call bdrv_co_unref() in coroutine context blockjob: Adhere to rate limit even when reentered early graph-lock: Honour read locks even in the main thread include/block/block-global-state.h | 8 +++--- include/block/block_int-common.h | 4 +-- include/block/blockjob_int.h | 14 +++++++--- block.c | 1 - block/commit.c | 7 ++--- block/create.c | 1 - block/crypto.c | 25 +++++++++-------- block/export/export.c | 6 +++-- block/graph-lock.c | 10 ------- block/mirror.c | 23 +++++++--------- block/parallels.c | 6 ++--- block/qcow.c | 6 ++--- block/qcow2.c | 43 +++++++++++++++++++++--------- block/qed.c | 6 ++--- block/raw-format.c | 2 +- block/stream.c | 7 ++--- block/vdi.c | 11 ++++---- block/vhdx.c | 8 +++--- block/vmdk.c | 27 +++++++++---------- block/vpc.c | 6 ++--- blockjob.c | 22 +++++++++++++-- qemu-img.c | 5 ++-- tests/unit/test-bdrv-drain.c | 6 ++--- 23 files changed, 138 insertions(+), 116 deletions(-)