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 5df761edc3..4fad40b96b 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 01495cb1c0..492296a90f 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, 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(
