From patchwork Wed May 3 23:11:19 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 9710507 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id E5A5C60351 for ; Wed, 3 May 2017 23:15:22 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D786828652 for ; Wed, 3 May 2017 23:15:22 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CC3B228682; Wed, 3 May 2017 23:15:22 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 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.wl.linuxfoundation.org (Postfix) with ESMTPS id 5548728652 for ; Wed, 3 May 2017 23:15:22 +0000 (UTC) Received: from localhost ([::1]:39007 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d63UP-0004VV-Le for patchwork-qemu-devel@patchwork.kernel.org; Wed, 03 May 2017 19:15:21 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59830) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d63Qp-00023S-Kn for qemu-devel@nongnu.org; Wed, 03 May 2017 19:11:40 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d63Qo-000617-7U for qemu-devel@nongnu.org; Wed, 03 May 2017 19:11:39 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44274) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1d63Qk-0005xS-8V; Wed, 03 May 2017 19:11:34 -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 5C96F201FB; Wed, 3 May 2017 23:11:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 5C96F201FB Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=mreitz@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 5C96F201FB Received: from localhost (ovpn-204-47.brq.redhat.com [10.40.204.47]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D065F182E5; Wed, 3 May 2017 23:11:32 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Thu, 4 May 2017 01:11:19 +0200 Message-Id: <20170503231120.23507-4-mreitz@redhat.com> In-Reply-To: <20170503231120.23507-1-mreitz@redhat.com> References: <20170503231120.23507-1-mreitz@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 [10.5.110.29]); Wed, 03 May 2017 23:11:33 +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] [PATCH 3/4] qcow2: Discard preallocated zero clusters 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: Kevin Wolf , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP In discard_single_l2(), we completely discard normal clusters instead of simply turning them into preallocated zero clusters. That means we should probably do the same with such preallocated zero clusters: Discard them instead of keeping them allocated. Reported-by: Eric Blake Signed-off-by: Max Reitz Reviewed-by: Eric Blake --- block/qcow2-cluster.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index fb91fd8979..31077d8102 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -1511,7 +1511,8 @@ static int discard_single_l2(BlockDriverState *bs, uint64_t offset, break; case QCOW2_CLUSTER_ZERO: - if (!full_discard) { + /* Preallocated zero clusters should be discarded in any case */ + if (!full_discard && (old_l2_entry & L2E_OFFSET_MASK) == 0) { continue; } break;