[Qemu-devel] [PATCH v2 3/9] qcow2: Factor out refcount comparison for check

[Max Reitz <mreitz@redhat.com>]

Put the code for comparing the calculated refcounts against the on-disk
refcounts during qemu-img check into an own function.

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/qcow2-refcount.c | 81 +++++++++++++++++++++++++++++---------------------
 1 file changed, 47 insertions(+), 34 deletions(-)

diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index b3c4edd..c477f04 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -1629,42 +1629,18 @@ static int calculate_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
 }
 
 /*
- * Checks an image for refcount consistency.
- *
- * Returns 0 if no errors are found, the number of errors in case the image is
- * detected as corrupted, and -errno when an internal error occurred.
+ * Compares the actual reference count for each cluster in the image against the
+ * refcount as reported by the refcount structures on-disk.
  */
-int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
-                          BdrvCheckMode fix)
+static void compare_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
+                              BdrvCheckMode fix, int64_t *highest_cluster,
+                              uint16_t *refcount_table, int64_t nb_clusters)
 {
     BDRVQcowState *s = bs->opaque;
-    int64_t size, i, highest_cluster, nb_clusters;
-    int refcount1, refcount2;
-    uint16_t *refcount_table = NULL;
-    int ret;
-
-    size = bdrv_getlength(bs->file);
-    if (size < 0) {
-        res->check_errors++;
-        return size;
-    }
-
-    nb_clusters = size_to_clusters(s, size);
-    if (nb_clusters > INT_MAX) {
-        res->check_errors++;
-        return -EFBIG;
-    }
-
-    res->bfi.total_clusters =
-        size_to_clusters(s, bs->total_sectors * BDRV_SECTOR_SIZE);
-
-    ret = calculate_refcounts(bs, res, fix, &refcount_table, &nb_clusters);
-    if (ret < 0) {
-        goto fail;
-    }
+    int64_t i;
+    int refcount1, refcount2, ret;
 
-    /* compare ref counts */
-    for (i = 0, highest_cluster = 0; i < nb_clusters; i++) {
+    for (i = 0, *highest_cluster = 0; i < nb_clusters; i++) {
         refcount1 = get_refcount(bs, i);
         if (refcount1 < 0) {
             fprintf(stderr, "Can't get refcount for cluster %" PRId64 ": %s\n",
@@ -1676,11 +1652,10 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
         refcount2 = refcount_table[i];
 
         if (refcount1 > 0 || refcount2 > 0) {
-            highest_cluster = i;
+            *highest_cluster = i;
         }
 
         if (refcount1 != refcount2) {
-
             /* Check if we're allowed to fix the mismatch */
             int *num_fixed = NULL;
             if (refcount1 > refcount2 && (fix & BDRV_FIX_LEAKS)) {
@@ -1713,6 +1688,44 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
             }
         }
     }
+}
+
+/*
+ * Checks an image for refcount consistency.
+ *
+ * Returns 0 if no errors are found, the number of errors in case the image is
+ * detected as corrupted, and -errno when an internal error occurred.
+ */
+int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
+                          BdrvCheckMode fix)
+{
+    BDRVQcowState *s = bs->opaque;
+    int64_t size, highest_cluster, nb_clusters;
+    uint16_t *refcount_table = NULL;
+    int ret;
+
+    size = bdrv_getlength(bs->file);
+    if (size < 0) {
+        res->check_errors++;
+        return size;
+    }
+
+    nb_clusters = size_to_clusters(s, size);
+    if (nb_clusters > INT_MAX) {
+        res->check_errors++;
+        return -EFBIG;
+    }
+
+    res->bfi.total_clusters =
+        size_to_clusters(s, bs->total_sectors * BDRV_SECTOR_SIZE);
+
+    ret = calculate_refcounts(bs, res, fix, &refcount_table, &nb_clusters);
+    if (ret < 0) {
+        goto fail;
+    }
+
+    compare_refcounts(bs, res, fix, &highest_cluster, refcount_table,
+                      nb_clusters);
 
     /* check OFLAG_COPIED */
     ret = check_oflag_copied(bs, res, fix);
-- 
2.0.3