From patchwork Tue Aug 25 08:32:52 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 11735187 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 C507D14F6 for ; Tue, 25 Aug 2020 08:38:47 +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 9B88720706 for ; Tue, 25 Aug 2020 08:38:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="dt0fHTUS" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9B88720706 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.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]:33830 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kAUTe-0005RV-T6 for patchwork-qemu-devel@patchwork.kernel.org; Tue, 25 Aug 2020 04:38:46 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60268) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kAUOw-000448-Np for qemu-devel@nongnu.org; Tue, 25 Aug 2020 04:33:54 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:25860) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kAUOu-0000cu-MI for qemu-devel@nongnu.org; Tue, 25 Aug 2020 04:33:54 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1598344431; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8B7SKqqJSMBjP0ELm9wSnZJeCmsuhrnaBBAsOjU5eyo=; b=dt0fHTUSxBnbLs5RXBsmIuNgsiGmg32UGnJguiTNMs6YYDidTWqb3eWBqvyzSVVOehhhxQ tD2c0imMl1YmA8FWHpGOt76awByu9oNr/0k51Um0WPuyfe7oEckAy3Rtmtz2xkwtWlpohA IcwMy5PxUaYIlGT1nCwPK+3C3yGVPgk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-189-bEhcX3w4NxehPdC_sGYRdQ-1; Tue, 25 Aug 2020 04:33:49 -0400 X-MC-Unique: bEhcX3w4NxehPdC_sGYRdQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 69F021074666; Tue, 25 Aug 2020 08:33:48 +0000 (UTC) Received: from localhost (ovpn-113-72.ams2.redhat.com [10.36.113.72]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 08D9B5D9CA; Tue, 25 Aug 2020 08:33:47 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Subject: [PULL 15/34] qcow2: Add qcow2_get_subcluster_range_type() Date: Tue, 25 Aug 2020 10:32:52 +0200 Message-Id: <20200825083311.1098442-16-mreitz@redhat.com> In-Reply-To: <20200825083311.1098442-1-mreitz@redhat.com> References: <20200825083311.1098442-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mreitz@redhat.com X-Mimecast-Spam-Score: 0.001 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=216.205.24.124; envelope-from=mreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/25 02:03:58 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.956, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no 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: Kevin Wolf , Peter Maydell , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" From: Alberto Garcia There are situations in which we want to know how many contiguous subclusters of the same type there are in a given cluster. This can be done by simply iterating over the subclusters and repeatedly calling qcow2_get_subcluster_type() for each one of them. However once we determined the type of a subcluster we can check the rest efficiently by counting the number of adjacent ones (or zeroes) in the bitmap. This is what this function does. Signed-off-by: Alberto Garcia Reviewed-by: Eric Blake Reviewed-by: Max Reitz Message-Id: Signed-off-by: Max Reitz --- block/qcow2-cluster.c | 51 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 0b762502f6..2fe7a0f79c 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -375,6 +375,57 @@ fail: return ret; } +/* + * For a given L2 entry, count the number of contiguous subclusters of + * the same type starting from @sc_from. Compressed clusters are + * treated as if they were divided into subclusters of size + * s->subcluster_size. + * + * Return the number of contiguous subclusters and set @type to the + * subcluster type. + * + * If the L2 entry is invalid return -errno and set @type to + * QCOW2_SUBCLUSTER_INVALID. + */ +G_GNUC_UNUSED +static int qcow2_get_subcluster_range_type(BlockDriverState *bs, + uint64_t l2_entry, + uint64_t l2_bitmap, + unsigned sc_from, + QCow2SubclusterType *type) +{ + BDRVQcow2State *s = bs->opaque; + uint32_t val; + + *type = qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, sc_from); + + if (*type == QCOW2_SUBCLUSTER_INVALID) { + return -EINVAL; + } else if (!has_subclusters(s) || *type == QCOW2_SUBCLUSTER_COMPRESSED) { + return s->subclusters_per_cluster - sc_from; + } + + switch (*type) { + case QCOW2_SUBCLUSTER_NORMAL: + val = l2_bitmap | QCOW_OFLAG_SUB_ALLOC_RANGE(0, sc_from); + return cto32(val) - sc_from; + + case QCOW2_SUBCLUSTER_ZERO_PLAIN: + case QCOW2_SUBCLUSTER_ZERO_ALLOC: + val = (l2_bitmap | QCOW_OFLAG_SUB_ZERO_RANGE(0, sc_from)) >> 32; + return cto32(val) - sc_from; + + case QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN: + case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC: + val = ((l2_bitmap >> 32) | l2_bitmap) + & ~QCOW_OFLAG_SUB_ALLOC_RANGE(0, sc_from); + return ctz32(val) - sc_from; + + default: + g_assert_not_reached(); + } +} + /* * Checks how many clusters in a given L2 slice are contiguous in the image * file. As soon as one of the flags in the bitmask stop_flags changes compared