From nobody Mon Feb 9 13:10:57 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org ARC-Seal: i=1; a=rsa-sha256; t=1593792487; cv=none; d=zohomail.com; s=zohoarc; b=jylgz++VRkq6WPNs7qISal3R9PFoo4w3Iup0/01U0w0OQ3Ton/aMi6bfGls7jLOPjhDdIF5w9Gfopvkl2gcpmWxsqM9VBWL/QTwkMD9HqFSNzQFaeNrigZM+n9ggUzVRo0aZP91WHmNap1Vqv+kBflbqu+tO2M1H0ub8kYBbEvc= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1593792487; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=6qQoyV/cm9Nvp5kDqRKMgyxeyG52rrfmDQLzMDkXXqo=; b=I3g901le6DXESjBrIZci+ZFlSJN687bcdV35VTzUZVLtQir9lnc7FetdUwmSQGlHnuATEasYr6n7WbOrZ3dWRx1heoqaOk0jXIRAEOj8bouPjhEtpy3/gQtX8nTJHdYvXe50/E51qojMDw4ImAxM9ZNiqhQQu80b6fCDDeawzuo= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1593792487975993.3586047425576; Fri, 3 Jul 2020 09:08:07 -0700 (PDT) Received: from localhost ([::1]:50284 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jrOEQ-0003L4-Oz for importer@patchew.org; Fri, 03 Jul 2020 12:08:06 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59026) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jrO5l-0003Nb-Bh; Fri, 03 Jul 2020 11:59:09 -0400 Received: from fanzine.igalia.com ([178.60.130.6]:41631) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jrO5j-0007RW-4U; Fri, 03 Jul 2020 11:59:08 -0400 Received: from [81.0.49.0] (helo=perseus.local) by fanzine.igalia.com with esmtpsa (Cipher TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim) id 1jrO5L-0001QV-3q; Fri, 03 Jul 2020 17:58:43 +0200 Received: from berto by perseus.local with local (Exim 4.92) (envelope-from ) id 1jrO52-0007Pq-09; Fri, 03 Jul 2020 17:58:24 +0200 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From; bh=6qQoyV/cm9Nvp5kDqRKMgyxeyG52rrfmDQLzMDkXXqo=; b=kuyx64gXorEDEfTAmbpyzc24cqfCL5Zzcf7JGhN7RZXyJXgav6VMecQjqgtsphu/rtJh/A2xEX4OBEzvUnoljDQ0yAXi8/HOqdni0UTkXtyBWWhv17qdRZqfKD06sHiXwGk4bjqpAbc7I+kYxfDhl8kyyAuS66d1XP5rKPHynolFFFUIBgNi2tb7TFpZB63phMzpU7aqEj4o925l+K6RkaHczs+1tsJvZfpUppDj6T/Hqs/zSUwVIBM6v6m+dU/ncIBwIA3T2vJ6Us+tOdDdcqY/okr4H5LtDQbiSAiemuyvQzWJwMnFAZ4O0Kf8Of5Hn2SjcG3y9C1Y9fLHL3Aepw==; From: Alberto Garcia To: qemu-devel@nongnu.org Subject: [PATCH v10 15/34] qcow2: Add qcow2_get_subcluster_range_type() Date: Fri, 3 Jul 2020 17:58:01 +0200 Message-Id: X-Mailer: git-send-email 2.20.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=178.60.130.6; envelope-from=berto@igalia.com; helo=fanzine.igalia.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/03 11:21:00 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x (no timestamps) [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=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: Kevin Wolf , Vladimir Sementsov-Ogievskiy , Alberto Garcia , qemu-block@nongnu.org, Derek Su , Max Reitz Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" 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 --- block/qcow2-cluster.c | 51 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 9ba60f3fde..751906c330 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -375,6 +375,57 @@ fail: return ret; } =20 +/* + * 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 =3D bs->opaque; + uint32_t val; + + *type =3D qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, sc_from); + + if (*type =3D=3D QCOW2_SUBCLUSTER_INVALID) { + return -EINVAL; + } else if (!has_subclusters(s) || *type =3D=3D QCOW2_SUBCLUSTER_COMPRE= SSED) { + return s->subclusters_per_cluster - sc_from; + } + + switch (*type) { + case QCOW2_SUBCLUSTER_NORMAL: + val =3D 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 =3D (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 =3D ((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 com= pared --=20 2.20.1