From nobody Mon Feb 9 10:54:14 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.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; Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zoho.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=1572125859; cv=none; d=zoho.com; s=zohoarc; b=jNmeCZ1eg3GADLGC/w4vD+6ynwBv3wtcc/0nrLlWiajOcAnU9MYEPylS2tLl3Ve9Yq7F0SxDMMGsfqSCGQ/CFerCgfc1sa987i/0ZM0QSp6YRAq/p/iC9snjA6yWJuIELyNt8v+8T/Kkzvdmc0qySmVthmxpR0MBf/Pe2O79cbc= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1572125859; 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=N02rNnYxAWKgjBXR/pQJOdFYoHP99UpZ8ZnG2b9Blmc=; b=hyIyr9DfOVHbleE184KJFf+aUFUp3hE0vCrs7iq2XPS3mFvk4U00jptVLVonO0/ReAD5UHlais1tTbdCc/FLiHFSJjiE9prA2X8WZeknBIKb8W29gJqaAAwz2wmWaMTUxqHeNRZDTuCXt+B6oUW4nqAtPxroYpjIsQ9g5zAUwOU= ARC-Authentication-Results: i=1; mx.zoho.com; dkim=fail; spf=pass (zoho.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 1572125859871934.846770162041; Sat, 26 Oct 2019 14:37:39 -0700 (PDT) Received: from localhost ([::1]:42560 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iOTkd-0007zm-Rm for importer@patchew.org; Sat, 26 Oct 2019 17:37:35 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60080) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iOTZk-00006r-A9 for qemu-devel@nongnu.org; Sat, 26 Oct 2019 17:26:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iOTZi-0005Ma-G4 for qemu-devel@nongnu.org; Sat, 26 Oct 2019 17:26:20 -0400 Received: from fanzine.igalia.com ([178.60.130.6]:42502) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1iOTZg-0005F2-9D; Sat, 26 Oct 2019 17:26:17 -0400 Received: from 87-100-137-117.bb.dnainternet.fi ([87.100.137.117] helo=perseus.local) by fanzine.igalia.com with esmtpsa (Cipher TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim) id 1iOTZI-000461-Rf; Sat, 26 Oct 2019 23:25:53 +0200 Received: from berto by perseus.local with local (Exim 4.92) (envelope-from ) id 1iOTZ0-0001PT-LK; Sun, 27 Oct 2019 00:25:34 +0300 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=N02rNnYxAWKgjBXR/pQJOdFYoHP99UpZ8ZnG2b9Blmc=; b=rOyGHSVfmoHnG/5ICKiJc/ngCQUxzYtznptpkSz0StpM7KtLQDjgG/HNUDeg+th317VpujRybKlUmnv5+/dxGEZF1z7dJdET28f5SPhXJqraSOHmT1N0dAsOYjsfIQtDWPOYbdGt84KKq+trHevJ5WQhGPC9MKzSCYxll+3BmyRB+mk9MvRgqB21XER2/tyPVJmvkg7WuL92LbJDP+Zvxm6TGiVNCkDTMEv69N+/61DNN2AxarfZw1DseYRHxkRmsHMnNHQP1FcaHf8RI9XLT2N3pDOyp24WAJUs207ybZBVWISbY4/qAv4wkporEoHzGDibPVW5sHl5Zm4JybX/jA==; From: Alberto Garcia To: qemu-devel@nongnu.org Subject: [RFC PATCH v2 14/26] qcow2: Add subcluster support to qcow2_get_cluster_offset() Date: Sun, 27 Oct 2019 00:25:16 +0300 Message-Id: <6932c2ddfe19a564cad7c54246290e166525fc46.1572125022.git.berto@igalia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x (no timestamps) [generic] [fuzzy] X-Received-From: 178.60.130.6 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 , Anton Nefedov , Alberto Garcia , qemu-block@nongnu.org, Max Reitz , Vladimir Sementsov-Ogievskiy , "Denis V . Lunev" 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" The logic of this function remains pretty much the same, except that it uses count_contiguous_subclusters(), which combines the logic of count_contiguous_clusters() / count_contiguous_clusters_unallocated() and checks individual subclusters. Signed-off-by: Alberto Garcia --- block/qcow2-cluster.c | 111 ++++++++++++++++++++---------------------- 1 file changed, 52 insertions(+), 59 deletions(-) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 990bc070af..e67559152f 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -372,66 +372,51 @@ fail: } =20 /* - * 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 - * to the first cluster, the search is stopped and the cluster is not coun= ted - * as contiguous. (This allows it, for example, to stop at the first compr= essed - * cluster which may require a different handling) + * Return the number of contiguous subclusters of the exact same type + * in a given L2 slice, starting from cluster @l2_index, subcluster + * @sc_index. At most @nb_clusters are checked. Allocated clusters are + * also required to be contiguous in the image file. */ -static int count_contiguous_clusters(BlockDriverState *bs, int nb_clusters, - int cluster_size, uint64_t *l2_slice, int l2_index, uint64_t stop_= flags) +static int count_contiguous_subclusters(BlockDriverState *bs, int nb_clust= ers, + unsigned sc_index, uint64_t *l2_sl= ice, + int l2_index) { BDRVQcow2State *s =3D bs->opaque; - int i; - QCow2ClusterType first_cluster_type; - uint64_t mask =3D stop_flags | L2E_OFFSET_MASK | QCOW_OFLAG_COMPRESSED; - uint64_t first_entry =3D get_l2_entry(s, l2_slice, l2_index); - uint64_t offset =3D first_entry & mask; - - first_cluster_type =3D qcow2_get_cluster_type(bs, first_entry); - if (first_cluster_type =3D=3D QCOW2_CLUSTER_UNALLOCATED) { - return 0; + int i, j, count =3D 0; + uint64_t l2_entry =3D get_l2_entry(s, l2_slice, l2_index); + uint64_t l2_bitmap =3D get_l2_bitmap(s, l2_slice, l2_index); + uint64_t expected_offset =3D l2_entry & L2E_OFFSET_MASK; + bool check_offset =3D true; + QCow2ClusterType type =3D + qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, sc_index); + + assert(type !=3D QCOW2_CLUSTER_INVALID); /* The caller should check th= is */ + + if (type =3D=3D QCOW2_CLUSTER_COMPRESSED) { + return 1; /* Compressed clusters are always counted one by one */ } =20 - /* must be allocated */ - assert(first_cluster_type =3D=3D QCOW2_CLUSTER_NORMAL || - first_cluster_type =3D=3D QCOW2_CLUSTER_ZERO_ALLOC); - - for (i =3D 0; i < nb_clusters; i++) { - uint64_t l2_entry =3D get_l2_entry(s, l2_slice, l2_index + i) & ma= sk; - if (offset + (uint64_t) i * cluster_size !=3D l2_entry) { - break; - } + if (type =3D=3D QCOW2_CLUSTER_UNALLOCATED || type =3D=3D QCOW2_CLUSTER= _ZERO_PLAIN) { + check_offset =3D false; } =20 - return i; -} - -/* - * Checks how many consecutive unallocated clusters in a given L2 - * slice have the same cluster type. - */ -static int count_contiguous_clusters_unallocated(BlockDriverState *bs, - int nb_clusters, - uint64_t *l2_slice, - int l2_index, - QCow2ClusterType wanted_t= ype) -{ - BDRVQcow2State *s =3D bs->opaque; - int i; - - assert(wanted_type =3D=3D QCOW2_CLUSTER_ZERO_PLAIN || - wanted_type =3D=3D QCOW2_CLUSTER_UNALLOCATED); for (i =3D 0; i < nb_clusters; i++) { - uint64_t entry =3D get_l2_entry(s, l2_slice, l2_index + i); - QCow2ClusterType type =3D qcow2_get_cluster_type(bs, entry); - - if (type !=3D wanted_type) { - break; + l2_entry =3D get_l2_entry(s, l2_slice, l2_index + i); + l2_bitmap =3D get_l2_bitmap(s, l2_slice, l2_index + i); + if (check_offset && expected_offset !=3D (l2_entry & L2E_OFFSET_MA= SK)) { + goto out; + } + for (j =3D (i =3D=3D 0) ? sc_index : 0; j < s->subclusters_per_clu= ster; j++) { + if (qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, j) !=3D= type) { + goto out; + } + count++; } + expected_offset +=3D s->cluster_size; } =20 - return i; +out: + return count; } =20 static int coroutine_fn do_perform_cow_read(BlockDriverState *bs, @@ -514,8 +499,8 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint= 64_t offset, unsigned int *bytes, uint64_t *cluster_offset) { BDRVQcow2State *s =3D bs->opaque; - unsigned int l2_index; - uint64_t l1_index, l2_offset, *l2_slice; + unsigned int l2_index, sc_index; + uint64_t l1_index, l2_offset, *l2_slice, l2_bitmap; int c; unsigned int offset_in_cluster; uint64_t bytes_available, bytes_needed, nb_clusters; @@ -569,7 +554,9 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint= 64_t offset, /* find the cluster offset for the given disk offset */ =20 l2_index =3D offset_to_l2_slice_index(s, offset); + sc_index =3D offset_to_sc_index(s, offset); *cluster_offset =3D get_l2_entry(s, l2_slice, l2_index); + l2_bitmap =3D get_l2_bitmap(s, l2_slice, l2_index); =20 nb_clusters =3D size_to_clusters(s, bytes_needed); /* bytes_needed <=3D *bytes + offset_in_cluster, both of which are uns= igned @@ -577,7 +564,7 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint= 64_t offset, * true */ assert(nb_clusters <=3D INT_MAX); =20 - type =3D qcow2_get_cluster_type(bs, *cluster_offset); + type =3D qcow2_get_subcluster_type(bs, *cluster_offset, l2_bitmap, sc_= index); if (s->qcow_version < 3 && (type =3D=3D QCOW2_CLUSTER_ZERO_PLAIN || type =3D=3D QCOW2_CLUSTER_ZERO_ALLOC)) { qcow2_signal_corruption(bs, true, -1, -1, "Zero cluster entry foun= d" @@ -587,6 +574,13 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uin= t64_t offset, goto fail; } switch (type) { + case QCOW2_CLUSTER_INVALID: + qcow2_signal_corruption(bs, true, -1, -1, "Invalid cluster entry f= ound " + " (L2 offset: %#" PRIx64 ", L2 index: %#x)= ", + l2_offset, l2_index); + ret =3D -EIO; + goto fail; + break; case QCOW2_CLUSTER_COMPRESSED: if (has_data_file(bs)) { qcow2_signal_corruption(bs, true, -1, -1, "Compressed cluster " @@ -602,16 +596,15 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, ui= nt64_t offset, break; case QCOW2_CLUSTER_ZERO_PLAIN: case QCOW2_CLUSTER_UNALLOCATED: - /* how many empty clusters ? */ - c =3D count_contiguous_clusters_unallocated(bs, nb_clusters, - l2_slice, l2_index, type= ); + c =3D count_contiguous_subclusters(bs, nb_clusters, sc_index, + l2_slice, l2_index); *cluster_offset =3D 0; break; case QCOW2_CLUSTER_ZERO_ALLOC: case QCOW2_CLUSTER_NORMAL: - /* how many allocated clusters ? */ - c =3D count_contiguous_clusters(bs, nb_clusters, s->cluster_size, - l2_slice, l2_index, QCOW_OFLAG_ZERO); + case QCOW2_CLUSTER_UNALLOCATED_SUBCLUSTER: + c =3D count_contiguous_subclusters(bs, nb_clusters, sc_index, + l2_slice, l2_index); *cluster_offset &=3D L2E_OFFSET_MASK; if (offset_into_cluster(s, *cluster_offset)) { qcow2_signal_corruption(bs, true, -1, -1, @@ -640,7 +633,7 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint= 64_t offset, =20 qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice); =20 - bytes_available =3D (int64_t)c * s->cluster_size; + bytes_available =3D ((int64_t)c + sc_index) * s->subcluster_size; =20 out: if (bytes_available > bytes_needed) { --=20 2.20.1