From patchwork Mon Nov 7 15:13:20 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 13034559 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 DEC3FC433FE for ; Mon, 7 Nov 2022 15:14:53 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1os3ob-0001qz-Nu; Mon, 07 Nov 2022 10:13:33 -0500 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 1os3oa-0001pw-CI for qemu-devel@nongnu.org; Mon, 07 Nov 2022 10:13:32 -0500 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 1os3oX-0006eM-0k for qemu-devel@nongnu.org; Mon, 07 Nov 2022 10:13:32 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1667834008; 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=pzU0JLObee2Hbn5huwOdt/BhlzFhd9gLq2lW2XktS3E=; b=KtB7Zi/HNrfUl0PJrKozJcThRTXYDvP5TY97mjI8QWSwHSJSlLxmAaLSKIPTNmJg8Wjgwa 7gESYBsexgm7z1lp22cEOMRgM2gkavao1PJW5w+yjS63aMhNXTu904YzzZ+qxdJrjNYWGS 1vcGC18DZUgyhMagfMYletyGN0h2U04= 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-196-JiwijxOTNcCx2wZoMe0Syg-1; Mon, 07 Nov 2022 10:13:27 -0500 X-MC-Unique: JiwijxOTNcCx2wZoMe0Syg-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id AF5753810787; Mon, 7 Nov 2022 15:13:26 +0000 (UTC) Received: from localhost (unknown [10.39.194.227]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5F517492B05; Mon, 7 Nov 2022 15:13:26 +0000 (UTC) From: Hanna Reitz To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, Hanna Reitz , Kevin Wolf , Stefan Hajnoczi Subject: [PATCH v2 2/3] block-backend: Update ctx immediately after root Date: Mon, 7 Nov 2022 16:13:20 +0100 Message-Id: <20221107151321.211175-3-hreitz@redhat.com> In-Reply-To: <20221107151321.211175-1-hreitz@redhat.com> References: <20221107151321.211175-1-hreitz@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 Received-SPF: pass client-ip=170.10.133.124; envelope-from=hreitz@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 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 blk_get_aio_context() asserts that blk->ctx is always equal to the root BDS's context (if there is a root BDS). Therefore, blk_do_set_aio_context() must update blk->ctx immediately after the root BDS's context has changed. Without this patch, the next patch would break iotest 238, because bdrv_drained_begin() (called by blk_do_set_aio_context()) may then invoke bdrv_child_get_parent_aio_context() on the root child, i.e. blk_get_aio_context(). However, by this point, blk->ctx would not have been updated and thus differ from the root node's context. This patch fixes that. Reviewed-by: Kevin Wolf Signed-off-by: Hanna Reitz --- block/block-backend.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/block/block-backend.c b/block/block-backend.c index ed2f4b67a2..b48c91f4e1 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -2158,6 +2158,11 @@ static int blk_do_set_aio_context(BlockBackend *blk, AioContext *new_context, return ret; } } + /* + * Make blk->ctx consistent with the root node before we invoke any + * other operations like drain that might inquire blk->ctx + */ + blk->ctx = new_context; if (tgm->throttle_state) { bdrv_drained_begin(bs); throttle_group_detach_aio_context(tgm); @@ -2166,9 +2171,10 @@ static int blk_do_set_aio_context(BlockBackend *blk, AioContext *new_context, } bdrv_unref(bs); + } else { + blk->ctx = new_context; } - blk->ctx = new_context; return 0; }