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 X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3B853C433DB for ; Thu, 11 Feb 2021 20:55:01 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id ADC0664DE2 for ; Thu, 11 Feb 2021 20:55:00 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ADC0664DE2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:33948 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lAIzL-0006ew-Pv for qemu-devel@archiver.kernel.org; Thu, 11 Feb 2021 15:54:59 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:43118) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lAIpg-0005wD-Hp for qemu-devel@nongnu.org; Thu, 11 Feb 2021 15:45:02 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:60120) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lAIpZ-0007Rk-7a for qemu-devel@nongnu.org; Thu, 11 Feb 2021 15:45:00 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1613076292; 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=9t4IkoAmXiHcfKk4F3GTc5helKS3pdW0WkOh9WuI2hA=; b=Nvl2XRfUeSD12IyV7TQ5DZ8NTlxGfG42M8hm0d0g9xreamPVLbBHqBVw1ZiFkK/5dwDHoJ 7PcOY3YJV5CA7eaY69NXrOhHNUKV70Y+pyGQHZ9HGo6TSrS+LyZqEZgqR+WdlYyLmxCdZ4 aqRZCw5Ltd/dVWcBu+Xct7x5V+OBKZ4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-281-4ZKmVndYN3CuOnGPlUL_Zw-1; Thu, 11 Feb 2021 15:44:48 -0500 X-MC-Unique: 4ZKmVndYN3CuOnGPlUL_Zw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A77CF5210; Thu, 11 Feb 2021 20:44:47 +0000 (UTC) Received: from blue.redhat.com (ovpn-114-150.phx2.redhat.com [10.3.114.150]) by smtp.corp.redhat.com (Postfix) with ESMTP id 097DD10013D7; Thu, 11 Feb 2021 20:44:46 +0000 (UTC) From: Eric Blake To: qemu-devel@nongnu.org Subject: [PATCH v2 4/4] utils: Deprecate inexact fractional suffix sizes Date: Thu, 11 Feb 2021 14:44:38 -0600 Message-Id: <20210211204438.1184395-5-eblake@redhat.com> In-Reply-To: <20210211204438.1184395-1-eblake@redhat.com> References: <20210211204438.1184395-1-eblake@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 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-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" Received-SPF: pass client-ip=216.205.24.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.569, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: vsementsov@virtuozzo.com, berrange@redhat.com, qemu-block@nongnu.org, "reviewer:Incompatible changes" , tao3.xu@intel.com, rjones@redhat.com, armbru@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" The value '1.1k' is inexact; 1126.4 bytes is not possible, so we happen to truncate it to 1126. Our use of fractional sizes is intended for convenience, but when a user specifies a fraction that is not a clean translation to binary, truncating/rounding behind their backs can cause confusion. Better is to deprecate inexact values, which still leaves '1.5k' as valid, but alerts the user to spell out their values as a precise byte number in cases where they are currently being rounded. Note that values like '0.1G' in the testsuite need adjustment as a result. Since qemu_strtosz() does not have an Err** parameter, and plumbing that in would be a much larger task, we instead go with just directly emitting the deprecation warning to stderr. Signed-off-by: Eric Blake --- I'm not a fan of this patch, but am proposing it for discussion purposes. --- docs/system/deprecated.rst | 9 +++++++++ tests/test-cutils.c | 6 +++--- tests/test-keyval.c | 4 ++-- tests/test-qemu-opts.c | 4 ++-- util/cutils.c | 9 +++++++-- 5 files changed, 23 insertions(+), 9 deletions(-) diff --git a/docs/system/deprecated.rst b/docs/system/deprecated.rst index 113c2e933f1b..2c9cb849eec5 100644 --- a/docs/system/deprecated.rst +++ b/docs/system/deprecated.rst @@ -154,6 +154,15 @@ Input parameters that take a size value should only use a size suffix the value is hexadecimal. That is, '0x20M' is deprecated, and should be written either as '32M' or as '0x2000000'. +inexact sizes via scaled fractions (since 6.0) +'''''''''''''''''''''''''''''''''''''''''''''' + +Input parameters that take a size value should only use a fractional +size (such as '1.5M') that will result in an exact byte value. The +use of inexact values (such as '1.1M') that require truncation or +rounding is deprecated, and you should instead consider writing your +unusual size in bytes (here, '1153433' or '1153434' as desired). + QEMU Machine Protocol (QMP) commands ------------------------------------ diff --git a/tests/test-cutils.c b/tests/test-cutils.c index bad3a6099389..c6c33866277b 100644 --- a/tests/test-cutils.c +++ b/tests/test-cutils.c @@ -2124,11 +2124,11 @@ static void test_qemu_strtosz_float(void) g_assert_cmpint(res, ==, 1024); g_assert(endptr == str + 3); - /* For convenience, we permit values that are not byte-exact */ - str = "12.345M"; + /* Fractional values should still be byte-exact */ + str = "12.125M"; err = qemu_strtosz(str, &endptr, &res); g_assert_cmpint(err, ==, 0); - g_assert_cmpint(res, ==, (uint64_t) (12.345 * MiB)); + g_assert_cmpint(res, ==, (uint64_t) (12.125 * MiB)); g_assert(endptr == str + 7); } diff --git a/tests/test-keyval.c b/tests/test-keyval.c index e20c07cf3ea5..7a45c22942e6 100644 --- a/tests/test-keyval.c +++ b/tests/test-keyval.c @@ -525,7 +525,7 @@ static void test_keyval_visit_size(void) visit_free(v); /* Suffixes */ - qdict = keyval_parse("sz1=8b,sz2=1.5k,sz3=2M,sz4=0.1G,sz5=16777215T", + qdict = keyval_parse("sz1=8b,sz2=1.5k,sz3=2M,sz4=0.125G,sz5=16777215T", NULL, NULL, &error_abort); v = qobject_input_visitor_new_keyval(QOBJECT(qdict)); qobject_unref(qdict); @@ -537,7 +537,7 @@ static void test_keyval_visit_size(void) visit_type_size(v, "sz3", &sz, &error_abort); g_assert_cmphex(sz, ==, 2 * MiB); visit_type_size(v, "sz4", &sz, &error_abort); - g_assert_cmphex(sz, ==, GiB / 10); + g_assert_cmphex(sz, ==, GiB / 8); visit_type_size(v, "sz5", &sz, &error_abort); g_assert_cmphex(sz, ==, 16777215ULL * TiB); visit_check_struct(v, &error_abort); diff --git a/tests/test-qemu-opts.c b/tests/test-qemu-opts.c index 6568e31a7229..549e994938fe 100644 --- a/tests/test-qemu-opts.c +++ b/tests/test-qemu-opts.c @@ -720,10 +720,10 @@ static void test_opts_parse_size(void) g_assert_cmphex(qemu_opt_get_size(opts, "size1", 0), ==, 8); g_assert_cmphex(qemu_opt_get_size(opts, "size2", 0), ==, 1536); g_assert_cmphex(qemu_opt_get_size(opts, "size3", 0), ==, 2 * MiB); - opts = qemu_opts_parse(&opts_list_02, "size1=0.1G,size2=16777215T", + opts = qemu_opts_parse(&opts_list_02, "size1=0.125G,size2=16777215T", false, &error_abort); g_assert_cmpuint(opts_count(opts), ==, 2); - g_assert_cmphex(qemu_opt_get_size(opts, "size1", 0), ==, GiB / 10); + g_assert_cmphex(qemu_opt_get_size(opts, "size1", 0), ==, GiB / 8); g_assert_cmphex(qemu_opt_get_size(opts, "size2", 0), ==, 16777215ULL * TiB); /* Beyond limit with suffix */ diff --git a/util/cutils.c b/util/cutils.c index 6a8a175e0d71..1154b9de131a 100644 --- a/util/cutils.c +++ b/util/cutils.c @@ -246,12 +246,13 @@ static int64_t suffix_mul(char suffix, int64_t unit) * The size parsing supports the following syntaxes * - 12345 - decimal, scale determined by @default_suffix and @unit * - 12345{bBkKmMgGtTpPeE} - decimal, scale determined by suffix and @unit - * - 12345.678{kKmMgGtTpPeE} - decimal, scale determined by suffix, and - * fractional portion is truncated to byte + * - 12345.678{kKmMgGtTpPeE} - decimal, scale determined by suffix, if + * fractional portion is exact * - 0x7fEE - hexadecimal, unit determined by @default_suffix * * The following cause a deprecation warning, and may be removed in the future * - 0xabc{kKmMgGtTpP} - hex with scaling suffix + * - 12345.678{kKmMgGtTpPeE} - decimal with inexact fraction that caused truncation * * The following are intentionally not supported * - octal, such as 08 @@ -342,6 +343,10 @@ static int do_strtosz(const char *nptr, const char **end, retval = -ERANGE; goto out; } + if (mul_required && fraction * mul != (uint64_t) (fraction * mul)) { + warn_report("Using a fractional size that is not an exact byte " + "multiple is deprecated: %s", nptr); + } *result = val * mul + (uint64_t) (fraction * mul); retval = 0; -- 2.30.1