From patchwork Fri Apr 15 06:19:11 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ren Kimura X-Patchwork-Id: 8845041 Return-Path: X-Original-To: patchwork-qemu-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 2536B9F54F for ; Fri, 15 Apr 2016 06:19:36 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 73311202EB for ; Fri, 15 Apr 2016 06:19:35 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C99FA2017D for ; Fri, 15 Apr 2016 06:19:34 +0000 (UTC) Received: from localhost ([::1]:55438 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aqx6L-0001wz-5Q for patchwork-qemu-devel@patchwork.kernel.org; Fri, 15 Apr 2016 02:19:33 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60506) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aqx6D-0001tj-7r for qemu-devel@nongnu.org; Fri, 15 Apr 2016 02:19:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aqx6C-0001Wi-9s for qemu-devel@nongnu.org; Fri, 15 Apr 2016 02:19:25 -0400 Received: from mail-pa0-x243.google.com ([2607:f8b0:400e:c03::243]:33130) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aqx67-0001WI-OU; Fri, 15 Apr 2016 02:19:19 -0400 Received: by mail-pa0-x243.google.com with SMTP id vv3so8574729pab.0; Thu, 14 Apr 2016 23:19:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id; bh=6EdHyu/msYYUI0L0m/rjv3ByGcgYMv3OirgcN6t1COU=; b=iyCUJvk2+sv4zNc2uylujHToaGcLa5ZbCAiR7zUXPPcmSjdgXGynh3M3XLkcQyUTnO KmAaULF6bfuq1EqNSgZDbQcAWMc1mwmtLGleNobAHFK2DyPmTbM7wNoC1LrFeB2yedph 3EueZvPDfFjK3AknhLeuM9VqDDGJ2nyrCrU5jxAW6SOd7Jk+Upbo6lrjOM/7HOkVZSQS uyCoHeY1ZK8nVLOunxXqYLgyqwROuvLz47z+f9aKFhtQXv8aOvTW9RqihM5Tc5ytZGDl qnO2/MnnZHMNcHK4e2F0tWglgz4M2mXkO7rKPf90QcJ/7HUkwfP0ht7JzEFV+LT4F8mz 6piQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=6EdHyu/msYYUI0L0m/rjv3ByGcgYMv3OirgcN6t1COU=; b=AV1nAyhlUIvOwzh8eyHgQRU4MbTu7uzGThX1hSkourGzg+pKvrfpAhQ9FL/jqHnl++ iaTVLgWdQG4XHwplEQINCdWjOL9UtrC1JuJKCuSkNUM6tOk5Vkyf2eJSavMD1HJJyxpq ZNMjd/0oG3inm1cM0jBj2+NlDXjVVZSK/18Z7AmPv3NOT/lqsGMtqoeRg4cNBkezzE+P mF9OfsE1eTLxm8lUYR7kGGl/7YFBp1E8TSd5/aKPk8Irr2O8hEsWIVF6yuhnUe/3uAvZ NO9j6+0YQMAlNVb9lSVZVGQ72hXoVquDTqCJwHelZdryHoZb3ry+m8aXPwvE0lNm/68q KR3w== X-Gm-Message-State: AOPr4FUsby22u0yq9OhM20NhVedjOGh+mneS2SfYQ4Hn+vzA66CjLe5x2qjFlYcXI33/Sw== X-Received: by 10.66.237.33 with SMTP id uz1mr27274255pac.5.1460701158931; Thu, 14 Apr 2016 23:19:18 -0700 (PDT) Received: from rkx-PC.flets-west.jp (p13009-ipngnfx01kobeminato.hyogo.ocn.ne.jp. [153.142.46.9]) by smtp.googlemail.com with ESMTPSA id a5sm1846549pat.19.2016.04.14.23.19.17 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 14 Apr 2016 23:19:18 -0700 (PDT) From: Ren Kimura To: mreitz@redhat.com Date: Fri, 15 Apr 2016 15:19:11 +0900 Message-Id: <1460701151-5984-1-git-send-email-rkx1209dev@gmail.com> X-Mailer: git-send-email 2.5.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2607:f8b0:400e:c03::243 Subject: [Qemu-devel] [PATCH v2] qemu-img: check block status of backing file when converting. X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, qemu-devel@nongnu.org, qemu-block@nongnu.org Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, T_DKIM_INVALID, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When converting images, check the block status of its backing file chain to avoid needlessly reading zeros. Signed-off-by: Ren Kimura --- qemu-img.c | 27 +++++++++++++++++++++++++-- 1 file changed, 25 insertions(+), 2 deletions(-) diff --git a/qemu-img.c b/qemu-img.c index 06264d9..6330f2a 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -1451,6 +1451,22 @@ static void convert_select_part(ImgConvertState *s, int64_t sector_num) } } +static int64_t get_backing_status(BlockDriverState *bs, + int64_t sector_num, + int nb_sectors, int *pnum) +{ + int64_t ret; + BlockDriverState *file; + ret = bdrv_get_block_status(bs, sector_num, nb_sectors, pnum, &file); + if (ret != BDRV_BLOCK_DATA && ret != BDRV_BLOCK_ZERO) { + if (bs->backing) { + ret = get_backing_status(bs->backing->bs, sector_num, + nb_sectors, pnum); + } + } + return ret; +} + static int convert_iteration_sectors(ImgConvertState *s, int64_t sector_num) { int64_t ret; @@ -1477,10 +1493,17 @@ static int convert_iteration_sectors(ImgConvertState *s, int64_t sector_num) } else if (!s->target_has_backing) { /* Without a target backing file we must copy over the contents of * the backing file as well. */ - /* TODO Check block status of the backing file chain to avoid + /* Check block status of the backing file chain to avoid * needlessly reading zeroes and limiting the iteration to the * buffer size */ - s->status = BLK_DATA; + ret = get_backing_status(blk_bs(s->src[s->src_cur]), + sector_num - s->src_cur_offset, + n, &n); + if (ret & BDRV_BLOCK_ZERO) { + s->status = BLK_ZERO; + } else { + s->status = BLK_DATA; + } } else { s->status = BLK_BACKING_FILE; }