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 0BA4CC433F5 for ; Mon, 21 Mar 2022 15:01:15 +0000 (UTC) Received: from localhost ([::1]:52830 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nWJWz-0002LM-IH for qemu-devel@archiver.kernel.org; Mon, 21 Mar 2022 11:01:13 -0400 Received: from eggs.gnu.org ([209.51.188.92]:32836) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nWJUp-00006t-Kb for qemu-devel@nongnu.org; Mon, 21 Mar 2022 10:58:59 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:50298) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nWJUn-0006IQ-3t for qemu-devel@nongnu.org; Mon, 21 Mar 2022 10:58:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1647874736; 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: in-reply-to:in-reply-to:references:references; bh=7qdPU828uMB6PEKfTd7lN8iFdm46yjy3ej5VAt1uVmE=; b=RO55Sa6FFnNI3iPJ/+PMvH/RItmCbVqL/1SnZzZor52nsgeXrNJOXv4ESVqSOunx+xE+SO qnAHmjEImMOqZk2P/Pnxtu7axs5dzGAkEEiPslIxLt/QjRV231CBgGL0mgvQGoxFgrHfZC fm4oQb+BY8EufXGZH/2v79d32Z5DYbg= 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-197-xCpO0RSMNWeW_hCQWjXz0Q-1; Mon, 21 Mar 2022 10:58:53 -0400 X-MC-Unique: xCpO0RSMNWeW_hCQWjXz0Q-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 0380B899EC2; Mon, 21 Mar 2022 14:58:52 +0000 (UTC) Received: from redhat.com (unknown [10.2.16.194]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 12CBC53C9; Mon, 21 Mar 2022 14:58:42 +0000 (UTC) Date: Mon, 21 Mar 2022 09:58:40 -0500 From: Eric Blake To: John Snow Subject: Re: [PATCH 04/15] iotests/040: Don't check image pattern on zero-length image Message-ID: <20220321145840.k24oqamholmek7dk@redhat.com> References: <20220318203655.676907-1-jsnow@redhat.com> <20220318203655.676907-5-jsnow@redhat.com> MIME-Version: 1.0 In-Reply-To: <20220318203655.676907-5-jsnow@redhat.com> User-Agent: NeoMutt/20211029-454-6adf99 X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eblake@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=170.10.129.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, 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_H4=0.001, RCVD_IN_MSPIKE_WL=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: , Cc: Kevin Wolf , Hanna Reitz , qemu-devel@nongnu.org, qemu-block@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Fri, Mar 18, 2022 at 04:36:44PM -0400, John Snow wrote: > qemu-io fails on read/write with zero-length raw images, so skip these > when running the zero-length image tests. On my first read, I wondered what we accomplish by rejecting zero-length reads on a zero-length image, and whether entering the rabbit hole of trying to make that corner case "work" differently makes more sense... > > Signed-off-by: John Snow > --- > tests/qemu-iotests/040 | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > > diff --git a/tests/qemu-iotests/040 b/tests/qemu-iotests/040 > index adf5815781..c4a90937dc 100755 > --- a/tests/qemu-iotests/040 > +++ b/tests/qemu-iotests/040 > @@ -86,8 +86,10 @@ class TestSingleDrive(ImageCommitTestCase): > qemu_img('create', '-f', iotests.imgfmt, > '-o', 'backing_file=%s' % mid_img, > '-F', iotests.imgfmt, test_img) > - qemu_io('-f', 'raw', '-c', 'write -P 0xab 0 524288', backing_img) > - qemu_io('-f', iotests.imgfmt, '-c', 'write -P 0xef 524288 524288', mid_img) > + if self.image_len: > + qemu_io('-f', 'raw', '-c', 'write -P 0xab 0 524288', backing_img) > + qemu_io('-f', iotests.imgfmt, '-c', 'write -P 0xef 524288 524288', > + mid_img) ...but now it is obvious - one of our test cases is attempting a non-zero-length modification to a zero-length file, and it does make sense for that modification attempt to fail, in which case, making the test special case the zero-length file is the right thing to do. Reviewed-by: Eric Blake -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org