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bh=POK1627KTH6bcgH86t074+LexWq35p1/PhByk7FiDnM=; b=Gt7d99FUT1A4myPpW+X0RON/WggZI5iiAOXW1qExI2llky82fM5tsSAzR99N0AROknYVcz iSkFyAzVQvhEnPABJevq1PGanUWfRNDbwEQOlZMxqevhQriQZbFZIbQbp4pYGB2NLkRswg 7gsTdtvT5hnyYw3Wxg6txrrMp+KdEo8= X-MC-Unique: avJGK8nfM5-jgVzPlDcKug-1 From: Max Reitz To: qemu-block@nongnu.org Subject: [PULL 21/34] qcow2: Add subcluster support to qcow2_get_host_offset() Date: Tue, 25 Aug 2020 10:32:58 +0200 Message-Id: <20200825083311.1098442-22-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 10.5.11.11 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 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; 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charset="utf-8" From: Alberto Garcia 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 Reviewed-by: Max Reitz Message-Id: [mreitz: Initialize expected_type to anything] Signed-off-by: Max Reitz --- 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 5df761edc3..4fad40b96b 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -710,29 +710,6 @@ static inline QCow2ClusterType qcow2_get_cluster_type(= BlockDriverState *bs, } } =20 -/* - * 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(BlockDri= verState *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(); + } } } =20 diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 5e7ae0843d..08ecb4ca0c 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -426,66 +426,66 @@ static int qcow2_get_subcluster_range_type(BlockDrive= rState *bs, } =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. 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_clust= ers, + unsigned sc_index, uint64_t *l2_sl= ice, + unsigned *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; + int i, count =3D 0; + bool check_offset =3D false; + uint64_t expected_offset =3D 0; + QCow2SubclusterType expected_type =3D QCOW2_SUBCLUSTER_NORMAL, type; =20 - first_cluster_type =3D qcow2_get_cluster_type(bs, first_entry); - if (first_cluster_type =3D=3D QCOW2_CLUSTER_UNALLOCATED) { - return 0; - } - - /* must be allocated */ - assert(first_cluster_type =3D=3D QCOW2_CLUSTER_NORMAL || - first_cluster_type =3D=3D QCOW2_CLUSTER_ZERO_ALLOC); + assert(*l2_index + nb_clusters <=3D s->l2_slice_size); =20 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) { + unsigned first_sc =3D (i =3D=3D 0) ? sc_index : 0; + uint64_t l2_entry =3D get_l2_entry(s, l2_slice, *l2_index + i); + uint64_t l2_bitmap =3D get_l2_bitmap(s, l2_slice, *l2_index + i); + int ret =3D qcow2_get_subcluster_range_type(bs, l2_entry, l2_bitma= p, + first_sc, &type); + if (ret < 0) { + *l2_index +=3D i; /* Point to the invalid entry */ + return -EIO; + } + if (i =3D=3D 0) { + if (type =3D=3D QCOW2_SUBCLUSTER_COMPRESSED) { + /* Compressed clusters are always processed one by one */ + return ret; + } + expected_type =3D type; + expected_offset =3D l2_entry & L2E_OFFSET_MASK; + check_offset =3D (type =3D=3D QCOW2_SUBCLUSTER_NORMAL || + type =3D=3D QCOW2_SUBCLUSTER_ZERO_ALLOC || + type =3D=3D QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC= ); + } else if (type !=3D expected_type) { break; + } else if (check_offset) { + expected_offset +=3D s->cluster_size; + if (expected_offset !=3D (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_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) { + count +=3D ret; + /* Stop if there are type changes before the end of the cluster */ + if (first_sc + ret < s->subclusters_per_cluster) { break; } } =20 - return i; + return count; } =20 static int coroutine_fn do_perform_cow_read(BlockDriverState *bs, @@ -574,12 +574,12 @@ int qcow2_get_host_offset(BlockDriverState *bs, uint6= 4_t offset, QCow2SubclusterType *subcluster_type) { BDRVQcow2State *s =3D 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; =20 offset_in_cluster =3D offset_into_cluster(s, offset); @@ -602,13 +602,13 @@ int qcow2_get_host_offset(BlockDriverState *bs, uint6= 4_t offset, =20 l1_index =3D offset_to_l1_index(s, offset); if (l1_index >=3D s->l1_size) { - type =3D QCOW2_CLUSTER_UNALLOCATED; + type =3D QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN; goto out; } =20 l2_offset =3D s->l1_table[l1_index] & L1E_OFFSET_MASK; if (!l2_offset) { - type =3D QCOW2_CLUSTER_UNALLOCATED; + type =3D QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN; goto out; } =20 @@ -629,7 +629,9 @@ int qcow2_get_host_offset(BlockDriverState *bs, uint64_= 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); l2_entry =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 @@ -637,9 +639,9 @@ int qcow2_get_host_offset(BlockDriverState *bs, uint64_= t offset, * true */ assert(nb_clusters <=3D INT_MAX); =20 - type =3D qcow2_get_cluster_type(bs, l2_entry); - if (s->qcow_version < 3 && (type =3D=3D QCOW2_CLUSTER_ZERO_PLAIN || - type =3D=3D QCOW2_CLUSTER_ZERO_ALLOC)) { + type =3D qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, sc_index); + if (s->qcow_version < 3 && (type =3D=3D QCOW2_SUBCLUSTER_ZERO_PLAIN || + type =3D=3D QCOW2_SUBCLUSTER_ZERO_ALLOC)) { qcow2_signal_corruption(bs, true, -1, -1, "Zero cluster entry foun= d" " in pre-v3 image (L2 offset: %#" PRIx64 ", L2 index: %#x)", l2_offset, l2_index); @@ -647,7 +649,9 @@ 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 da= ta " @@ -656,23 +660,16 @@ int qcow2_get_host_offset(BlockDriverState *bs, uint6= 4_t offset, ret =3D -EIO; goto fail; } - /* Compressed clusters can only be processed one by one */ - c =3D 1; *host_offset =3D l2_entry & L2E_COMPRESSED_OFFSET_SIZE_MASK; 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= ); + case QCOW2_SUBCLUSTER_ZERO_PLAIN: + case QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN: 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 =3D l2_entry & L2E_OFFSET_MASK; *host_offset =3D host_cluster_offset + offset_in_cluster; - /* how many allocated clusters ? */ - c =3D 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 %#" @@ -698,9 +695,18 @@ int qcow2_get_host_offset(BlockDriverState *bs, uint64= _t offset, abort(); } =20 + sc =3D 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 f= ound " + " (L2 offset: %#" PRIx64 ", L2 index: %#x)= ", + l2_offset, l2_index); + ret =3D -EIO; + goto fail; + } 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)sc + sc_index) << s->subcluster_bits; =20 out: if (bytes_available > bytes_needed) { @@ -713,7 +719,7 @@ out: assert(bytes_available - offset_in_cluster <=3D UINT_MAX); *bytes =3D bytes_available - offset_in_cluster; =20 - *subcluster_type =3D qcow2_cluster_to_subcluster_type(type); + *subcluster_type =3D type; =20 return 0; =20 --=20 2.26.2