From patchwork Sun May 24 14:51:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alberto Garcia X-Patchwork-Id: 11567415 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 1944815E4 for ; Sun, 24 May 2020 15:05:44 +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 D3947206D5 for ; Sun, 24 May 2020 15:05:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=igalia.com header.i=@igalia.com header.b="XvuwMBU8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D3947206D5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=igalia.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]:42984 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jcsC7-0001Mt-2J for patchwork-qemu-devel@patchwork.kernel.org; Sun, 24 May 2020 11:05:43 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45862) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jcs01-00034j-Dw; Sun, 24 May 2020 10:53:13 -0400 Received: from fanzine.igalia.com ([178.60.130.6]:37992) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jcrzy-0002lk-2U; Sun, 24 May 2020 10:53:13 -0400 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=r9h4dLQSBF3SFB6+9xcKHSJ+KZ4mJEr2CS21yaFblV0=; b=XvuwMBU8JGxHkVXD8P7hF066FoXAVCMY16oD3G3L56/ONv85HJhRJfvVJiZm9/t10xKU5I4rh1o3npTVKLPWtpwI9/McafoMFbEHMzyK5NY/QkXALbl79dwjuSCraxCYga0kTD1WK0vmOISmkr6c1n/7gaNWYtpBSkpmpehO+DpWQQGaoaePfVVcB9HBuIyzp+hZhQryg5Kqrk7S5TefxyA0xmdrKAs8L9H8uHgHfn5VEvNaQO7I1qGl5SfVAkKJmNymzHA/n7h/jZjujikh1SEoMp+Nm7DL0joBhQWA7qVJMcgHBj7ZRP92tZHQStVAXeOKqcTr/A2cR9oTwCO9yw==; Received: from [81.0.38.199] (helo=perseus.local) by fanzine.igalia.com with esmtpsa (Cipher TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim) id 1jcrzF-0007Gc-NT; Sun, 24 May 2020 16:52:25 +0200 Received: from berto by perseus.local with local (Exim 4.92) (envelope-from ) id 1jcryv-0005Ke-9z; Sun, 24 May 2020 16:52:05 +0200 From: Alberto Garcia To: qemu-devel@nongnu.org Subject: [PATCH v6 21/32] qcow2: Add subcluster support to qcow2_get_host_offset() Date: Sun, 24 May 2020 16:51:41 +0200 Message-Id: X-Mailer: git-send-email 2.20.1 In-Reply-To: References: MIME-Version: 1.0 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 = 2020/05/24 10:52:20 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_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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" 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. qcow2_cluster_to_subcluster_type() is not necessary as a separate function anymore so it's inlined into its caller. Signed-off-by: Alberto Garcia --- block/qcow2.h | 38 ++++------- block/qcow2-cluster.c | 150 ++++++++++++++++++++++-------------------- 2 files changed, 92 insertions(+), 96 deletions(-) diff --git a/block/qcow2.h b/block/qcow2.h index 84c06d9bba..32c68ead9a 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -710,29 +710,6 @@ static inline QCow2ClusterType qcow2_get_cluster_type(BlockDriverState *bs, } } -/* - * For an image without extended L2 entries, return the - * QCow2SubclusterType equivalent of a given QCow2ClusterType. - */ -static inline -QCow2SubclusterType qcow2_cluster_to_subcluster_type(QCow2ClusterType type) -{ - switch (type) { - case QCOW2_CLUSTER_COMPRESSED: - return QCOW2_SUBCLUSTER_COMPRESSED; - case QCOW2_CLUSTER_ZERO_PLAIN: - return QCOW2_SUBCLUSTER_ZERO_PLAIN; - case QCOW2_CLUSTER_ZERO_ALLOC: - return QCOW2_SUBCLUSTER_ZERO_ALLOC; - case QCOW2_CLUSTER_NORMAL: - return QCOW2_SUBCLUSTER_NORMAL; - case QCOW2_CLUSTER_UNALLOCATED: - return QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN; - default: - g_assert_not_reached(); - } -} - /* * In an image without subsclusters @l2_bitmap is ignored and * @sc_index must be 0. @@ -776,7 +753,20 @@ QCow2SubclusterType qcow2_get_subcluster_type(BlockDriverState *bs, g_assert_not_reached(); } } else { - return qcow2_cluster_to_subcluster_type(type); + switch (type) { + case QCOW2_CLUSTER_COMPRESSED: + return QCOW2_SUBCLUSTER_COMPRESSED; + case QCOW2_CLUSTER_ZERO_PLAIN: + return QCOW2_SUBCLUSTER_ZERO_PLAIN; + case QCOW2_CLUSTER_ZERO_ALLOC: + return QCOW2_SUBCLUSTER_ZERO_ALLOC; + case QCOW2_CLUSTER_NORMAL: + return QCOW2_SUBCLUSTER_NORMAL; + case QCOW2_CLUSTER_UNALLOCATED: + return QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN; + default: + g_assert_not_reached(); + } } } diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 59dd9bda29..2f3bd3a882 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -426,66 +426,66 @@ static int qcow2_get_subcluster_range_type(BlockDriverState *bs, } /* - * 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 - * to the first cluster, the search is stopped and the cluster is not counted - * as contiguous. (This allows it, for example, to stop at the first compressed - * 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. Allocated subclusters are required to be contiguous in + * the image file. + * At most @nb_clusters are checked (note that this means clusters, + * not subclusters). + * Compressed clusters are always processed one by one but for the + * purpose of this count they are treated as if they were divided into + * subclusters of size s->subcluster_size. + * On failure return -errno and update @l2_index to point to the + * invalid entry. */ -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_clusters, + unsigned sc_index, uint64_t *l2_slice, + unsigned *l2_index) { BDRVQcow2State *s = bs->opaque; - int i; - QCow2ClusterType first_cluster_type; - uint64_t mask = stop_flags | L2E_OFFSET_MASK | QCOW_OFLAG_COMPRESSED; - uint64_t first_entry = get_l2_entry(s, l2_slice, l2_index); - uint64_t offset = first_entry & mask; + int i, count = 0; + bool check_offset; + uint64_t expected_offset; + QCow2SubclusterType expected_type, type; - first_cluster_type = qcow2_get_cluster_type(bs, first_entry); - if (first_cluster_type == QCOW2_CLUSTER_UNALLOCATED) { - return 0; - } - - /* must be allocated */ - assert(first_cluster_type == QCOW2_CLUSTER_NORMAL || - first_cluster_type == QCOW2_CLUSTER_ZERO_ALLOC); + assert(*l2_index + nb_clusters <= s->l2_size); for (i = 0; i < nb_clusters; i++) { - uint64_t l2_entry = get_l2_entry(s, l2_slice, l2_index + i) & mask; - if (offset + (uint64_t) i * cluster_size != l2_entry) { + unsigned first_sc = (i == 0) ? sc_index : 0; + uint64_t l2_entry = get_l2_entry(s, l2_slice, *l2_index + i); + uint64_t l2_bitmap = get_l2_bitmap(s, l2_slice, *l2_index + i); + int ret = qcow2_get_subcluster_range_type(bs, l2_entry, l2_bitmap, + first_sc, &type); + if (ret < 0) { + *l2_index += i; /* Point to the invalid entry */ + return -EIO; + } + if (i == 0) { + if (type == QCOW2_SUBCLUSTER_COMPRESSED) { + /* Compressed clusters are always processed one by one */ + return ret; + } + expected_type = type; + expected_offset = l2_entry & L2E_OFFSET_MASK; + check_offset = (type == QCOW2_SUBCLUSTER_NORMAL || + type == QCOW2_SUBCLUSTER_ZERO_ALLOC || + type == QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC); + } else if (type != expected_type) { break; + } else if (check_offset) { + expected_offset += s->cluster_size; + if (expected_offset != (l2_entry & L2E_OFFSET_MASK)) { + break; + } } - } - - 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_type) -{ - BDRVQcow2State *s = bs->opaque; - int i; - - assert(wanted_type == QCOW2_CLUSTER_ZERO_PLAIN || - wanted_type == QCOW2_CLUSTER_UNALLOCATED); - for (i = 0; i < nb_clusters; i++) { - uint64_t entry = get_l2_entry(s, l2_slice, l2_index + i); - QCow2ClusterType type = qcow2_get_cluster_type(bs, entry); - - if (type != wanted_type) { + count += ret; + /* Stop if there are type changes before the end of the cluster */ + if (first_sc + ret < s->subclusters_per_cluster) { break; } } - return i; + return count; } static int coroutine_fn do_perform_cow_read(BlockDriverState *bs, @@ -574,12 +574,12 @@ int qcow2_get_host_offset(BlockDriverState *bs, uint64_t offset, QCow2SubclusterType *subcluster_type) { BDRVQcow2State *s = bs->opaque; - unsigned int l2_index; - uint64_t l1_index, l2_offset, *l2_slice, l2_entry; - int c; + unsigned int l2_index, sc_index; + uint64_t l1_index, l2_offset, *l2_slice, l2_entry, l2_bitmap; + int sc; unsigned int offset_in_cluster; uint64_t bytes_available, bytes_needed, nb_clusters; - QCow2ClusterType type; + QCow2SubclusterType type; int ret; offset_in_cluster = offset_into_cluster(s, offset); @@ -600,13 +600,13 @@ int qcow2_get_host_offset(BlockDriverState *bs, uint64_t offset, l1_index = offset_to_l1_index(s, offset); if (l1_index >= s->l1_size) { - type = QCOW2_CLUSTER_UNALLOCATED; + type = QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN; goto out; } l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK; if (!l2_offset) { - type = QCOW2_CLUSTER_UNALLOCATED; + type = QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN; goto out; } @@ -627,7 +627,9 @@ int qcow2_get_host_offset(BlockDriverState *bs, uint64_t offset, /* find the cluster offset for the given disk offset */ l2_index = offset_to_l2_slice_index(s, offset); + sc_index = offset_to_sc_index(s, offset); l2_entry = get_l2_entry(s, l2_slice, l2_index); + l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index); nb_clusters = size_to_clusters(s, bytes_needed); /* bytes_needed <= *bytes + offset_in_cluster, both of which are unsigned @@ -635,9 +637,9 @@ int qcow2_get_host_offset(BlockDriverState *bs, uint64_t offset, * true */ assert(nb_clusters <= INT_MAX); - type = qcow2_get_cluster_type(bs, l2_entry); - if (s->qcow_version < 3 && (type == QCOW2_CLUSTER_ZERO_PLAIN || - type == QCOW2_CLUSTER_ZERO_ALLOC)) { + type = qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, sc_index); + if (s->qcow_version < 3 && (type == QCOW2_SUBCLUSTER_ZERO_PLAIN || + type == QCOW2_SUBCLUSTER_ZERO_ALLOC)) { qcow2_signal_corruption(bs, true, -1, -1, "Zero cluster entry found" " in pre-v3 image (L2 offset: %#" PRIx64 ", L2 index: %#x)", l2_offset, l2_index); @@ -645,7 +647,9 @@ int qcow2_get_host_offset(BlockDriverState *bs, uint64_t offset, goto fail; } switch (type) { - case QCOW2_CLUSTER_COMPRESSED: + case QCOW2_SUBCLUSTER_INVALID: + break; /* This is handled by count_contiguous_subclusters() below */ + case QCOW2_SUBCLUSTER_COMPRESSED: if (has_data_file(bs)) { qcow2_signal_corruption(bs, true, -1, -1, "Compressed cluster " "entry found in image with external data " @@ -654,24 +658,17 @@ int qcow2_get_host_offset(BlockDriverState *bs, uint64_t offset, ret = -EIO; goto fail; } - /* Compressed clusters can only be processed one by one */ - c = 1; *host_offset = l2_entry & L2E_COMPRESSED_OFFSET_SIZE_MASK; break; - case QCOW2_CLUSTER_ZERO_PLAIN: - case QCOW2_CLUSTER_UNALLOCATED: - /* how many empty clusters ? */ - c = count_contiguous_clusters_unallocated(bs, nb_clusters, - l2_slice, l2_index, type); + case QCOW2_SUBCLUSTER_ZERO_PLAIN: + case QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN: *host_offset = 0; break; - case QCOW2_CLUSTER_ZERO_ALLOC: - case QCOW2_CLUSTER_NORMAL: { + case QCOW2_SUBCLUSTER_ZERO_ALLOC: + case QCOW2_SUBCLUSTER_NORMAL: + case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC: { uint64_t host_cluster_offset = l2_entry & L2E_OFFSET_MASK; *host_offset = host_cluster_offset + offset_in_cluster; - /* how many allocated clusters ? */ - c = count_contiguous_clusters(bs, nb_clusters, s->cluster_size, - l2_slice, l2_index, QCOW_OFLAG_ZERO); if (offset_into_cluster(s, host_cluster_offset)) { qcow2_signal_corruption(bs, true, -1, -1, "Cluster allocation offset %#" @@ -697,9 +694,18 @@ int qcow2_get_host_offset(BlockDriverState *bs, uint64_t offset, abort(); } + sc = count_contiguous_subclusters(bs, nb_clusters, sc_index, + l2_slice, &l2_index); + if (sc < 0) { + qcow2_signal_corruption(bs, true, -1, -1, "Invalid cluster entry found " + " (L2 offset: %#" PRIx64 ", L2 index: %#x)", + l2_offset, l2_index); + ret = -EIO; + goto fail; + } qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice); - bytes_available = (int64_t)c * s->cluster_size; + bytes_available = ((int64_t)sc + sc_index) << s->subcluster_bits; out: if (bytes_available > bytes_needed) { @@ -712,7 +718,7 @@ out: assert(bytes_available - offset_in_cluster <= UINT_MAX); *bytes = bytes_available - offset_in_cluster; - *subcluster_type = qcow2_cluster_to_subcluster_type(type); + *subcluster_type = type; return 0;