From patchwork Fri Jul 3 13:13:43 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Shinkevich X-Patchwork-Id: 11641899 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1D24713B4 for ; Fri, 3 Jul 2020 13:16:46 +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 F254F20675 for ; Fri, 3 Jul 2020 13:16:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F254F20675 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=virtuozzo.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:42158 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jrLYb-000362-7Q for patchwork-qemu-devel@patchwork.kernel.org; Fri, 03 Jul 2020 09:16:45 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43542) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jrLW0-0006px-3B; Fri, 03 Jul 2020 09:14:04 -0400 Received: from relay.sw.ru ([185.231.240.75]:60336 helo=relay3.sw.ru) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jrLVv-0007eM-S6; Fri, 03 Jul 2020 09:14:03 -0400 Received: from [172.16.25.136] (helo=localhost.sw.ru) by relay3.sw.ru with esmtp (Exim 4.93) (envelope-from ) id 1jrLVj-0004Vj-Nf; Fri, 03 Jul 2020 16:13:47 +0300 From: Andrey Shinkevich To: qemu-block@nongnu.org Subject: [PATCH v8 03/10] qcow2_format.py: change Qcow2BitmapExt initialization method Date: Fri, 3 Jul 2020 16:13:43 +0300 Message-Id: <1593782030-521984-4-git-send-email-andrey.shinkevich@virtuozzo.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1593782030-521984-1-git-send-email-andrey.shinkevich@virtuozzo.com> References: <1593782030-521984-1-git-send-email-andrey.shinkevich@virtuozzo.com> Received-SPF: pass client-ip=185.231.240.75; envelope-from=andrey.shinkevich@virtuozzo.com; helo=relay3.sw.ru X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/03 09:13:53 X-ACL-Warn: Detected OS = Linux 3.11 and newer X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN 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: kwolf@redhat.com, vsementsov@virtuozzo.com, qemu-devel@nongnu.org, mreitz@redhat.com, andrey.shinkevich@virtuozzo.com, den@openvz.org Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" There are two ways to initialize a class derived from Qcow2Struct: 1. Pass a block of binary data to the constructor. 2. Pass the file descriptor to allow reading the file from constructor. Let's change the Qcow2BitmapExt initialization method from 1 to 2 to support a scattered reading in the initialization chain. The implementation comes with the patch that follows. Suggested-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Andrey Shinkevich --- tests/qemu-iotests/qcow2_format.py | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/tests/qemu-iotests/qcow2_format.py b/tests/qemu-iotests/qcow2_format.py index 2f3681b..1435e34 100644 --- a/tests/qemu-iotests/qcow2_format.py +++ b/tests/qemu-iotests/qcow2_format.py @@ -63,7 +63,8 @@ class Qcow2StructMeta(type): class Qcow2Struct(metaclass=Qcow2StructMeta): - """Qcow2Struct: base class for qcow2 data structures + """ + Qcow2Struct: base class for qcow2 data structures Successors should define fields class variable, which is: list of tuples, each of three elements: @@ -113,6 +114,9 @@ class Qcow2BitmapExt(Qcow2Struct): ('u64', '{:#x}', 'bitmap_directory_offset') ) + def __init__(self, fd): + super().__init__(fd=fd) + QCOW2_EXT_MAGIC_BITMAPS = 0x23852875 @@ -173,7 +177,13 @@ class QcowHeaderExtension(Qcow2Struct): self.data_str = data_str if self.magic == QCOW2_EXT_MAGIC_BITMAPS: - self.obj = Qcow2BitmapExt(data=self.data) + assert fd is not None + position = fd.tell() + # Step back to reread data + padded = (self.length + 7) & ~7 + fd.seek(-padded, 1) + self.obj = Qcow2BitmapExt(fd=fd) + fd.seek(position) else: self.obj = None