From patchwork Fri May 6 16:26:42 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Blake X-Patchwork-Id: 619362 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3r1cmd0Fx3z9syq for ; Sat, 7 May 2016 02:34:09 +1000 (AEST) Received: from localhost ([::1]:59130 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ayihX-0002HI-LM for incoming@patchwork.ozlabs.org; Fri, 06 May 2016 12:34:03 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40347) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ayiba-000863-Dn for qemu-devel@nongnu.org; Fri, 06 May 2016 12:28:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ayibF-00069Z-Jd for qemu-devel@nongnu.org; Fri, 06 May 2016 12:27:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36767) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ayiax-0005xj-Gi; Fri, 06 May 2016 12:27:15 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0F33F478; Fri, 6 May 2016 16:26:59 +0000 (UTC) Received: from red.redhat.com (ovpn-113-38.phx2.redhat.com [10.3.113.38]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u46GQn2p016098; Fri, 6 May 2016 12:26:58 -0400 From: Eric Blake To: qemu-devel@nongnu.org Date: Fri, 6 May 2016 10:26:42 -0600 Message-Id: <1462552005-4887-17-git-send-email-eblake@redhat.com> In-Reply-To: <1462552005-4887-1-git-send-email-eblake@redhat.com> References: <1462552005-4887-1-git-send-email-eblake@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v7 16/19] nbd: Switch to byte-based block access 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, Paolo Bonzini , qemu-block@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Sector-based blk_read() should die; switch to byte-based blk_pread() instead. Add a constant for our magic number 512, to make it obvious that this size will NOT change even if BDRV_SECTOR_SIZE does, even though the two happen to be the same for now. Split assignments from conditionals to keep checkpatch.pl happy. Signed-off-by: Eric Blake --- v7: new magic number --- qemu-nbd.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/qemu-nbd.c b/qemu-nbd.c index c55b40f..3e54113 100644 --- a/qemu-nbd.c +++ b/qemu-nbd.c @@ -46,6 +46,8 @@ #define QEMU_NBD_OPT_TLSCREDS 261 #define QEMU_NBD_OPT_IMAGE_OPTS 262 +#define MBR_SIZE 512 + static NBDExport *exp; static bool newproto; static int verbose; @@ -159,12 +161,13 @@ static int find_partition(BlockBackend *blk, int partition, off_t *offset, off_t *size) { struct partition_record mbr[4]; - uint8_t data[512]; + uint8_t data[MBR_SIZE]; int i; int ext_partnum = 4; int ret; - if ((ret = blk_read(blk, 0, data, 1)) < 0) { + ret = blk_pread(blk, 0, data, sizeof(data)); + if (ret < 0) { error_report("error while reading: %s", strerror(-ret)); exit(EXIT_FAILURE); } @@ -182,10 +185,12 @@ static int find_partition(BlockBackend *blk, int partition, if (mbr[i].system == 0xF || mbr[i].system == 0x5) { struct partition_record ext[4]; - uint8_t data1[512]; + uint8_t data1[MBR_SIZE]; int j; - if ((ret = blk_read(blk, mbr[i].start_sector_abs, data1, 1)) < 0) { + ret = blk_pread(blk, mbr[i].start_sector_abs * MBR_SIZE, + data1, sizeof(data1)); + if (ret < 0) { error_report("error while reading: %s", strerror(-ret)); exit(EXIT_FAILURE); }