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 93D4EC77B7A for ; Thu, 25 May 2023 12:47:52 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1q2ANV-0007x9-98; Thu, 25 May 2023 08:47:37 -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 1q2ANT-0007vg-Eg for qemu-devel@nongnu.org; Thu, 25 May 2023 08:47:35 -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 1q2ANQ-0001zO-VM for qemu-devel@nongnu.org; Thu, 25 May 2023 08:47:35 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1685018852; 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=SzPVRx3SpG8K/P12nVcLZ+sMp9q+PLUAJ01e7rH3vVU=; b=KYAgKUrAHPDJJk/4dj3SuUd5Nb9RwIoUG6A6/wRoq+h8rB1T7r+/b+o4xT5mJ6Mb/u2r+h sWhSxbkYtch3UMs4vFeGJFB43BlN0c2MNS0JfJKlFLef7QLRBGbzhV5lgyhx8NLc9Zq38l btgxaxt+AzHC0hkU0w9F1qzCD21unIk= 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-104-6VDcqu9sPYO5jN4oiIE--A-1; Thu, 25 May 2023 08:47:30 -0400 X-MC-Unique: 6VDcqu9sPYO5jN4oiIE--A-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 8EE3A85A5B5; Thu, 25 May 2023 12:47:30 +0000 (UTC) Received: from merkur.fritz.box (unknown [10.39.194.166]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7E8067AF5; Thu, 25 May 2023 12:47:29 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, stefanha@redhat.com, hreitz@redhat.com, eblake@redhat.com, qemu-devel@nongnu.org Subject: [PATCH 06/12] qcow2: Fix open with 'file' in iothread Date: Thu, 25 May 2023 14:47:07 +0200 Message-Id: <20230525124713.401149-7-kwolf@redhat.com> In-Reply-To: <20230525124713.401149-1-kwolf@redhat.com> References: <20230525124713.401149-1-kwolf@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 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, 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 qcow2_open() doesn't work correctly when opening the 'file' child moves bs to an iothread, for several reasons: - It uses BDRV_POLL_WHILE() to wait for the qcow2_open_entry() coroutine, which involves dropping the AioContext lock for bs when it is not in the main context - but we don't hold it, so this crashes. - It runs the qcow2_open_entry() coroutine in the current thread instead of the new AioContext of bs. - qcow2_open_entry() doesn't notify the main loop when it's done. This patches fixes these issues around delegating work to a coroutine. Temporarily dropping the main AioContext lock is not necessary because we know we run in the main thread. Signed-off-by: Kevin Wolf --- block/qcow2.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/block/qcow2.c b/block/qcow2.c index b00b4e7575..7f3948360d 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -1904,6 +1904,8 @@ static void coroutine_fn qcow2_open_entry(void *opaque) qoc->ret = qcow2_do_open(qoc->bs, qoc->options, qoc->flags, true, qoc->errp); qemu_co_mutex_unlock(&s->lock); + + aio_wait_kick(); } static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, @@ -1929,8 +1931,10 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, assert(!qemu_in_coroutine()); assert(qemu_get_current_aio_context() == qemu_get_aio_context()); - qemu_coroutine_enter(qemu_coroutine_create(qcow2_open_entry, &qoc)); - BDRV_POLL_WHILE(bs, qoc.ret == -EINPROGRESS); + + aio_co_enter(bdrv_get_aio_context(bs), + qemu_coroutine_create(qcow2_open_entry, &qoc)); + AIO_WAIT_WHILE_UNLOCKED(NULL, qoc.ret == -EINPROGRESS); return qoc.ret; } -- 2.40.1