From nobody Wed Apr 16 07:38:00 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1499448083154418.4130538268862; Fri, 7 Jul 2017 10:21:23 -0700 (PDT) Received: from localhost ([::1]:57751 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dTWwT-00070O-Sc for importer@patchew.org; Fri, 07 Jul 2017 13:21:21 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42117) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dTWlW-0005NV-1L for qemu-devel@nongnu.org; Fri, 07 Jul 2017 13:10:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dTWlV-0008GI-2Y for qemu-devel@nongnu.org; Fri, 07 Jul 2017 13:10:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56848) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dTWlS-0008Bo-4N; Fri, 07 Jul 2017 13:09:58 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 28C57A4FB7; Fri, 7 Jul 2017 17:09:57 +0000 (UTC) Received: from noname.redhat.com (ovpn-117-34.ams2.redhat.com [10.36.117.34]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2AA8461F23; Fri, 7 Jul 2017 17:09:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 28C57A4FB7 Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=kwolf@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 28C57A4FB7 From: Kevin Wolf To: qemu-block@nongnu.org Date: Fri, 7 Jul 2017 19:07:54 +0200 Message-Id: <1499447335-6125-40-git-send-email-kwolf@redhat.com> In-Reply-To: <1499447335-6125-1-git-send-email-kwolf@redhat.com> References: <1499447335-6125-1-git-send-email-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Fri, 07 Jul 2017 17:09:57 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 039/100] block: Minimize raw use of bds->total_sectors 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 Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Eric Blake bdrv_is_allocated_above() was relying on intermediate->total_sectors, which is a field that can have stale contents depending on the value of intermediate->has_variable_length. An audit shows that we are safe (we were first calling through bdrv_co_get_block_status() which in turn calls bdrv_nb_sectors() and therefore just refreshed the current length), but it's nicer to favor our accessor functions to avoid having to repeat such an audit, even if it means refresh_total_sectors() is called more frequently. Suggested-by: John Snow Signed-off-by: Eric Blake Reviewed-by: Manos Pitsidianakis Reviewed-by: Jeff Cody Reviewed-by: John Snow Signed-off-by: Kevin Wolf --- block/io.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/block/io.c b/block/io.c index 6656d7f..aad7fd3 100644 --- a/block/io.c +++ b/block/io.c @@ -1947,6 +1947,7 @@ int bdrv_is_allocated_above(BlockDriverState *top, intermediate =3D top; while (intermediate && intermediate !=3D base) { int64_t pnum_inter; + int64_t size_inter; int psectors_inter; =20 ret =3D bdrv_is_allocated(intermediate, sector_num * BDRV_SECTOR_S= IZE, @@ -1962,15 +1963,12 @@ int bdrv_is_allocated_above(BlockDriverState *top, return 1; } =20 - /* - * [sector_num, nb_sectors] is unallocated on top but intermediate - * might have - * - * [sector_num+x, nr_sectors] allocated. - */ + size_inter =3D bdrv_nb_sectors(intermediate); + if (size_inter < 0) { + return size_inter; + } if (n > psectors_inter && - (intermediate =3D=3D top || - sector_num + psectors_inter < intermediate->total_sectors)) { + (intermediate =3D=3D top || sector_num + psectors_inter < size= _inter)) { n =3D psectors_inter; } =20 --=20 1.8.3.1