diff options
| -rw-r--r-- | block/qcow2-cluster.c | 150 | ||||
| -rw-r--r-- | block/qcow2.h | 38 |
2 files changed, 92 insertions, 96 deletions
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(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 = false; + uint64_t expected_offset = 0; + QCow2SubclusterType expected_type = QCOW2_SUBCLUSTER_NORMAL, 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_slice_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); @@ -602,13 +602,13 @@ 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; } @@ -629,7 +629,9 @@ 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 @@ -637,9 +639,9 @@ 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); @@ -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 data " @@ -656,23 +660,16 @@ 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: 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 %#" @@ -698,9 +695,18 @@ 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) { @@ -713,7 +719,7 @@ 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 5df761edc3..4fad40b96b 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -711,29 +711,6 @@ 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. * Return QCOW2_SUBCLUSTER_INVALID if an invalid l2 entry is detected @@ -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(); + } } } |