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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 8df0f67316..71d4cc518a 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