From patchwork Wed Feb 16 10:53:52 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 12748418 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 B4093C433F5 for ; Wed, 16 Feb 2022 10:56:08 +0000 (UTC) Received: from localhost ([::1]:37870 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nKHyh-0001cX-RU for qemu-devel@archiver.kernel.org; Wed, 16 Feb 2022 05:56:07 -0500 Received: from eggs.gnu.org ([209.51.188.92]:52304) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nKHwm-0006if-V7 for qemu-devel@nongnu.org; Wed, 16 Feb 2022 05:54:08 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:25300) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nKHwi-0001lB-Pd for qemu-devel@nongnu.org; Wed, 16 Feb 2022 05:54:07 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1645008843; 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; bh=IsbYHWu9b1cpBmsKSBqa69x7B21ZHCIg2nmSpo7BAZI=; b=dGaoRv7P/u/oqaMSfMEbTFVjyL91aqcArj0HOoyh5b9jI4Z0vbVJWVooOtCXUzy1LpfZGh xa3slANcJwSex3XnUGp0Cj2+8MRCRcOcOGk5MSG6/dkE1pMwhlzwAihm+swt2/6Ut+ZPjA EktL1HR/vDRsdy91uLygs+HkPF9vwu0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-638--Byhz5IGNU-KWZc1V4NHtA-1; Wed, 16 Feb 2022 05:53:58 -0500 X-MC-Unique: -Byhz5IGNU-KWZc1V4NHtA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D2F96802924; Wed, 16 Feb 2022 10:53:57 +0000 (UTC) Received: from localhost (unknown [10.39.195.8]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 718FB60C2E; Wed, 16 Feb 2022 10:53:57 +0000 (UTC) From: Hanna Reitz To: qemu-block@nongnu.org Subject: [PATCH v2 0/3] block: Make bdrv_refresh_limits() non-recursive Date: Wed, 16 Feb 2022 11:53:52 +0100 Message-Id: <20220216105355.30729-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=hreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com 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: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.083, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, 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: , Cc: Kevin Wolf , Hanna Reitz , Eric Blake , qemu-devel@nongnu.org, Stefan Hajnoczi Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Hi, v1 with detailed reasoning: https://lists.nongnu.org/archive/html/qemu-block/2022-02/msg00508.html This series makes bdrv_refresh_limits() non-recursive so that it is sufficient for callers to ensure that the node on which they call it will not receive concurrent I/O requests (instead of ensuring the same for the whole subtree). We need to ensure such I/O does not happen because bdrv_refresh_limits() is not atomic and will produce intermediate invalid values, which will break concurrent I/O requests that read these values. v2: - Use separate `try` block to clean up in patch 2 instead of putting the `os.remove()` in the existing one (which would cause the second `os.remove()` to be skipped if the first one failed) git-backport-diff against v1: Key: [----] : patches are identical [####] : number of functional differences between upstream/downstream patch [down] : patch is downstream-only The flags [FC] indicate (F)unctional and (C)ontextual differences, respectively 001/3:[----] [--] 'block: Make bdrv_refresh_limits() non-recursive' 002/3:[0005] [FC] 'iotests: Allow using QMP with the QSD' 003/3:[----] [--] 'iotests/graph-changes-while-io: New test' Hanna Reitz (3): block: Make bdrv_refresh_limits() non-recursive iotests: Allow using QMP with the QSD iotests/graph-changes-while-io: New test block/io.c | 4 - tests/qemu-iotests/iotests.py | 32 ++++++- .../qemu-iotests/tests/graph-changes-while-io | 91 +++++++++++++++++++ .../tests/graph-changes-while-io.out | 5 + 4 files changed, 127 insertions(+), 5 deletions(-) create mode 100755 tests/qemu-iotests/tests/graph-changes-while-io create mode 100644 tests/qemu-iotests/tests/graph-changes-while-io.out Reviewed-by: Stefan Hajnoczi