[RFC,V4,23/30] qcow2: Add check_dedup_l2 in order to check l2 of dedup table.

diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 9aef608..0c6e75a 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -1045,6 +1045,43 @@  fail:
     return -EIO;
 }
 
+static int check_dedup_l2(BlockDriverState *bs, BdrvCheckResult *res,
+                          int64_t l2_offset)
+{
+    BDRVQcowState *s = bs->opaque;
+    uint64_t *l2_table;
+    int i, l2_size;
+
+    /* Read L2 table from disk */
+    l2_size = s->cluster_size;
+    l2_table = g_malloc(l2_size);
+
+    if (bdrv_pread(bs->file, l2_offset, l2_table, l2_size) != l2_size) {
+        goto fail;
+    }
+
+    /* Do the actual checks */
+    for (i = 0; i < (s->l2_size - 5); i += 5) {
+        uint64_t first_logical_offset = be64_to_cpu(l2_table[i + 4]) &
+                                        ~QCOW_FLAG_FIRST;
+        if (first_logical_offset > (bs->total_sectors * BDRV_SECTOR_SIZE)) {
+            fprintf(stderr, "ERROR: l2 deduplication first_logical_offset"
+                    "=%" PRIi64 " outside of deduplicated volume in l2 table "
+                    "with offset %" PRIi64 ".\n", first_logical_offset,
+                    l2_offset);
+            res->corruptions++;
+        }
+    }
+
+    g_free(l2_table);
+    return 0;
+
+fail:
+    fprintf(stderr, "ERROR: I/O error in check_dedup_l2\n");
+    g_free(l2_table);
+    return -EIO;
+}
+
 /*
  * Increases the refcount for the L1 table, its L2 tables and all referenced
  * clusters in the given refcount table. While doing so, performs some checks
@@ -1058,7 +1095,8 @@  static int check_refcounts_l1(BlockDriverState *bs,
                               uint16_t *refcount_table,
                               int refcount_table_size,
                               int64_t l1_table_offset, int l1_size,
-                              int check_copied)
+                              int check_copied,
+                              bool dedup)
 {
     BDRVQcowState *s = bs->opaque;
     uint64_t *l1_table, l2_offset, l1_size2;
@@ -1114,11 +1152,19 @@  static int check_refcounts_l1(BlockDriverState *bs,
                 res->corruptions++;
             }
 
-            /* Process and check L2 entries */
-            ret = check_refcounts_l2(bs, res, refcount_table,
-                refcount_table_size, l2_offset, check_copied);
-            if (ret < 0) {
-                goto fail;
+            if (dedup) {
+                /* Process and check dedup l2 entries */
+                ret = check_dedup_l2(bs, res, l2_offset);
+                if (ret < 0) {
+                    goto fail;
+                }
+                } else {
+                /* Process and check L2 entries */
+                ret = check_refcounts_l2(bs, res, refcount_table,
+                    refcount_table_size, l2_offset, check_copied);
+                if (ret < 0) {
+                    goto fail;
+                }
             }
         }
     }
@@ -1158,14 +1204,15 @@  int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
 
     /* current L1 table */
     ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters,
-                       s->l1_table_offset, s->l1_size, 1);
+                       s->l1_table_offset, s->l1_size, 1, false);
     if (ret < 0) {
         goto fail;
     }
 
     if (s->has_dedup) {
         ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters,
-                                 s->dedup_table_offset, s->dedup_table_size, 0);
+                                 s->dedup_table_offset, s->dedup_table_size,
+                                 0, true);
         if (ret < 0) {
             goto fail;
         }
@@ -1175,7 +1222,7 @@  int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
     for(i = 0; i < s->nb_snapshots; i++) {
         sn = s->snapshots + i;
         ret = check_refcounts_l1(bs, res, refcount_table, nb_clusters,
-            sn->l1_table_offset, sn->l1_size, 0);
+            sn->l1_table_offset, sn->l1_size, 0, false);
         if (ret < 0) {
             goto fail;
         }