Signed-off-by: Benoit Canet <ben...@irqsave.net>
---
block/qcow2-cluster.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++++
block/qcow2.h | 4 ++++
2 files changed, 56 insertions(+)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 5b1d20d..fedcf57 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -514,6 +514,58 @@ out:
return ret;
}
+/* Check if a cluster is to deduplicate given it's index
+ *
+ * @index: The logical index of the cluster starting from 0
+ * @physical_sect: The physical sector of the cluster as return value
+ * @err: 0 on success, negative on error
+ * @ret: True if the cluster is to deduplicate else false
+ */
+bool qcow2_is_cluster_to_dedup(BlockDriverState *bs,
+ uint64_t index,
+ uint64_t *physical_sect,
+ int *err)
+{
+ BDRVQcowState *s = bs->opaque;
+ unsigned int l1_index, l2_index;
+ uint64_t offset;
+ uint64_t l2_offset;
+ uint64_t *l2_table = NULL;
+
+ *physical_sect = 0;
+ *err = 0;
+
+ l1_index = index >> s->l2_bits;
+
+ if (l1_index >= s->l1_size) {
+ return false;
+ }
+
+ /* no l1 entry */
+ if (!(s->l1_table[l1_index] & QCOW_OFLAG_COPIED)) {
+ return false;
+ }
+
+ l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK;
+
+ *err = l2_load(bs, l2_offset, &l2_table);
+ if (*err < 0) {
+ return false;
+ }
+
+ l2_index = index & (s->l2_size - 1);
+
+ offset = be64_to_cpu(l2_table[l2_index]);
+ *physical_sect = (offset & L2E_OFFSET_MASK) >> 9;
+
+ *err = qcow2_cache_put(bs, s->l2_table_cache, (void **) &l2_table);
+ if (*err < 0) {
+ return false;
+ }
+
+ return offset & QCOW_OFLAG_TO_DEDUP;
+}
+
/*
* get_cluster_table
*
diff --git a/block/qcow2.h b/block/qcow2.h
index bc1ba33..0232088 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -440,6 +440,10 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs,
QCowL2Meta *m);
int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
int nb_sectors);
int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors);
+bool qcow2_is_cluster_to_dedup(BlockDriverState *bs,
+ uint64_t index,
+ uint64_t *physical_sect,
+ int *ret);
/* qcow2-snapshot.c functions */
int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
--
1.7.10.4
