From patchwork Sun Dec 22 11:36:56 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alberto Garcia X-Patchwork-Id: 11307401 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 A6912138D for ; Sun, 22 Dec 2019 11:59:03 +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 6B2282070A for ; Sun, 22 Dec 2019 11:59:03 +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="PCO91fBu" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6B2282070A 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]:47014 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iizt0-0008N0-AT for patchwork-qemu-devel@patchwork.kernel.org; Sun, 22 Dec 2019 06:59:02 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:43842) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iizZA-0003Nn-81 for qemu-devel@nongnu.org; Sun, 22 Dec 2019 06:38:34 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iizZ7-0006od-V6 for qemu-devel@nongnu.org; Sun, 22 Dec 2019 06:38:31 -0500 Received: from fanzine.igalia.com ([178.60.130.6]:34976) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1iizZ7-0004V2-9M; Sun, 22 Dec 2019 06:38:29 -0500 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=9iMosx7u4f6rdZZvmG+CDPsOCgSu+D4AascyNAkVXR8=; b=PCO91fBulDti5ftVodihVg7DWKeHtTbQvkE1W6jFmcrX1NLJsTdIhwqP+CPCdGSDtMgpRyoVrFMBfjArnhC6NffV4PptLkMN+H0onpijscPKsTVS1pIPQvGvZU5gG71+hCwCebLNYP6kNtlDQD7EeWAmB889WUb3GaCZ0QN5WDnN2Kt+HdUiJmyiNQ0NM8yq3xaUlL1rWxsbpva7fMr4o7cl1hbYL3fziuuVhdu5KXbWFuI81WNQmzEuFnO4LCOMIXO75M6bgjZTFNBzBrduHY4ZeP9mUMR4lt8BkAGhlPiixO3hA5e6nODoS7P8qHtqs07sDBNv//p59dTedXSGhA==; Received: from [80.30.182.172] (helo=perseus.local) by fanzine.igalia.com with esmtpsa (Cipher TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim) id 1iizYU-0005dH-SN; Sun, 22 Dec 2019 12:37:53 +0100 Received: from berto by perseus.local with local (Exim 4.92) (envelope-from ) id 1iizXu-0001Vw-MG; Sun, 22 Dec 2019 12:37:14 +0100 From: Alberto Garcia To: qemu-devel@nongnu.org Subject: [RFC PATCH v3 15/27] qcow2: Add subcluster support to qcow2_get_cluster_offset() Date: Sun, 22 Dec 2019 12:36:56 +0100 Message-Id: <020909580d10ee5b9681961b52b8372ee892d35d.1577014346.git.berto@igalia.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: References: MIME-Version: 1.0 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+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. Signed-off-by: Alberto Garcia Reviewed-by: Max Reitz --- block/qcow2-cluster.c | 136 ++++++++++++++++++++---------------------- block/qcow2.h | 36 +++++------ 2 files changed, 80 insertions(+), 92 deletions(-) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index c6eb480ee8..c10601a828 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -372,66 +372,55 @@ fail: } /* - * 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). */ -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, + int 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; - - first_cluster_type = qcow2_get_cluster_type(bs, first_entry); - if (first_cluster_type == QCOW2_CLUSTER_UNALLOCATED) { - return 0; + int i, j, count = 0; + uint64_t l2_entry = get_l2_entry(s, l2_slice, l2_index); + uint64_t l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index); + uint64_t expected_offset = l2_entry & L2E_OFFSET_MASK; + bool check_offset = true; + QCow2SubclusterType type = + qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, sc_index); + + assert(type != QCOW2_SUBCLUSTER_INVALID); /* The caller should check this */ + + if (type == QCOW2_SUBCLUSTER_COMPRESSED) { + /* Compressed clusters are always processed one by one */ + return s->subclusters_per_cluster - sc_index; } - /* must be allocated */ - assert(first_cluster_type == QCOW2_CLUSTER_NORMAL || - first_cluster_type == QCOW2_CLUSTER_ZERO_ALLOC); - - 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) { - break; - } + if (type == QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN || + type == QCOW2_SUBCLUSTER_ZERO_PLAIN) { + check_offset = false; } - 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) { - break; + l2_entry = get_l2_entry(s, l2_slice, l2_index + i); + l2_bitmap = get_l2_bitmap(s, l2_slice, l2_index + i); + if (check_offset && expected_offset != (l2_entry & L2E_OFFSET_MASK)) { + goto out; + } + for (j = (i == 0) ? sc_index : 0; j < s->subclusters_per_cluster; j++) { + if (qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, j) != type) { + goto out; + } + count++; } + expected_offset += s->cluster_size; } - return i; +out: + return count; } static int coroutine_fn do_perform_cow_read(BlockDriverState *bs, @@ -515,12 +504,12 @@ int qcow2_get_cluster_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; - int c; + unsigned int l2_index, sc_index; + uint64_t l1_index, l2_offset, *l2_slice, 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); @@ -570,7 +559,9 @@ int qcow2_get_cluster_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); *cluster_offset = 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 @@ -578,9 +569,9 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, * true */ assert(nb_clusters <= INT_MAX); - type = qcow2_get_cluster_type(bs, *cluster_offset); - if (s->qcow_version < 3 && (type == QCOW2_CLUSTER_ZERO_PLAIN || - type == QCOW2_CLUSTER_ZERO_ALLOC)) { + type = qcow2_get_subcluster_type(bs, *cluster_offset, 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); @@ -588,7 +579,13 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, goto fail; } switch (type) { - case QCOW2_CLUSTER_COMPRESSED: + case QCOW2_SUBCLUSTER_INVALID: + 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; + 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 " @@ -598,21 +595,20 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, goto fail; } /* Compressed clusters can only be processed one by one */ - c = 1; + sc = s->subclusters_per_cluster - sc_index; *cluster_offset &= 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: + sc = count_contiguous_subclusters(bs, nb_clusters, sc_index, + l2_slice, l2_index); *cluster_offset = 0; break; - case QCOW2_CLUSTER_ZERO_ALLOC: - case QCOW2_CLUSTER_NORMAL: - /* how many allocated clusters ? */ - c = count_contiguous_clusters(bs, nb_clusters, s->cluster_size, - l2_slice, l2_index, QCOW_OFLAG_ZERO); + case QCOW2_SUBCLUSTER_ZERO_ALLOC: + case QCOW2_SUBCLUSTER_NORMAL: + case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC: + sc = count_contiguous_subclusters(bs, nb_clusters, sc_index, + l2_slice, l2_index); *cluster_offset &= L2E_OFFSET_MASK; if (offset_into_cluster(s, *cluster_offset)) { qcow2_signal_corruption(bs, true, -1, -1, @@ -641,7 +637,7 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, 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) { @@ -654,7 +650,7 @@ 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; diff --git a/block/qcow2.h b/block/qcow2.h index 37b7e25989..ae7973a2c2 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -651,27 +651,6 @@ 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. */ static inline @@ -720,7 +699,20 @@ 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(); + } } }