diff --git a/block/parallels.c b/block/parallels.c
index 136865d53e..5ed58826bb 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -768,57 +768,87 @@ parallels_check_outside_image(BlockDriverState *bs, BdrvCheckResult *res,
     return 0;
 }
 
+static int64_t GRAPH_RDLOCK
+parallels_check_unused_clusters(BlockDriverState *bs, bool truncate)
+{
+    BDRVParallelsState *s = bs->opaque;
+    int64_t leak, file_size, end_off = 0;
+    int ret;
+
+    file_size = bdrv_getlength(bs->file->bs);
+    if (file_size < 0) {
+        return file_size;
+    }
+
+    if (s->used_bmap_size > 0) {
+        end_off = find_last_bit(s->used_bmap, s->used_bmap_size);
+        if (end_off == s->used_bmap_size) {
+            end_off = 0;
+        } else {
+            end_off = (end_off + 1) * s->cluster_size;
+        }
+    }
+
+    end_off += s->data_start * BDRV_SECTOR_SIZE;
+    leak = file_size - end_off;
+    if (leak < 0) {
+        return -EINVAL;
+    }
+    if (!truncate || leak == 0) {
+        return leak;
+    }
+
+    ret = bdrv_truncate(bs->file, end_off, true, PREALLOC_MODE_OFF, 0, NULL);
+    if (ret) {
+        return ret;
+    }
+
+    s->data_end = end_off / BDRV_SECTOR_SIZE;
+
+    parallels_free_used_bitmap(bs);
+    ret = parallels_fill_used_bitmap(bs);
+    if (ret < 0) {
+        return ret;
+    }
+
+    return leak;
+}
+
 static int coroutine_fn GRAPH_RDLOCK
 parallels_check_leak(BlockDriverState *bs, BdrvCheckResult *res,
                      BdrvCheckMode fix, bool explicit)
 {
     BDRVParallelsState *s = bs->opaque;
-    int64_t size, count;
-    int ret;
+    int64_t leak, count, size;
+
+    leak = parallels_check_unused_clusters(bs, fix & BDRV_FIX_LEAKS);
+    if (leak < 0) {
+        res->check_errors++;
+        return leak;
+    }
+    if (leak == 0) {
+        return 0;
+    }
 
     size = bdrv_co_getlength(bs->file->bs);
     if (size < 0) {
         res->check_errors++;
         return size;
     }
-    if (size <= res->image_end_offset) {
+    res->image_end_offset = size;
+
+    if (!explicit) {
         return 0;
     }
 
-    count = DIV_ROUND_UP(size - res->image_end_offset, s->cluster_size);
-    if (explicit) {
-        fprintf(stderr,
-                "%s space leaked at the end of the image %" PRId64 "\n",
-                fix & BDRV_FIX_LEAKS ? "Repairing" : "ERROR",
-                size - res->image_end_offset);
-        res->leaks += count;
-    }
+    count = DIV_ROUND_UP(leak, s->cluster_size);
+    fprintf(stderr,
+            "%s space leaked at the end of the image %" PRId64 "\n",
+            fix & BDRV_FIX_LEAKS ? "Repairing" : "ERROR", leak);
+    res->leaks += count;
+
     if (fix & BDRV_FIX_LEAKS) {
-        Error *local_err = NULL;
-
-        /*
-         * In order to really repair the image, we must shrink it.
-         * That means we have to pass exact=true.
-         */
-        ret = bdrv_co_truncate(bs->file, res->image_end_offset, true,
-                               PREALLOC_MODE_OFF, 0, &local_err);
-        if (ret < 0) {
-            error_report_err(local_err);
-            res->check_errors++;
-            return ret;
-        }
-        s->data_end = res->image_end_offset >> BDRV_SECTOR_BITS;
-
-        parallels_free_used_bitmap(bs);
-        ret = parallels_fill_used_bitmap(bs);
-        if (ret == -ENOMEM) {
-            res->check_errors++;
-            return ret;
-        }
-
-        if (explicit) {
-            res->leaks_fixed += count;
-        }
+        res->leaks_fixed += count;
     }
 
     return 0;
@@ -1454,23 +1484,6 @@ fail:
     return ret;
 }
 
-static int GRAPH_RDLOCK parallels_truncate_unused_clusters(BlockDriverState *bs)
-{
-    BDRVParallelsState *s = bs->opaque;
-    uint64_t end_off = 0;
-    if (s->used_bmap_size > 0) {
-        end_off = find_last_bit(s->used_bmap, s->used_bmap_size);
-        if (end_off == s->used_bmap_size) {
-            end_off = 0;
-        } else {
-            end_off = (end_off + 1) * s->cluster_size;
-        }
-    }
-    end_off += s->data_start * BDRV_SECTOR_SIZE;
-    s->data_end = end_off / BDRV_SECTOR_SIZE;
-    return bdrv_truncate(bs->file, end_off, true, PREALLOC_MODE_OFF, 0, NULL);
-}
-
 static int GRAPH_RDLOCK parallels_inactivate(BlockDriverState *bs)
 {
     BDRVParallelsState *s = bs->opaque;
@@ -1488,7 +1501,7 @@ static int GRAPH_RDLOCK parallels_inactivate(BlockDriverState *bs)
     parallels_update_header(bs);
 
     /* errors are ignored, so we might as well pass exact=true */
-    ret = parallels_truncate_unused_clusters(bs);
+    ret = parallels_check_unused_clusters(bs, true);
     if (ret < 0) {
         error_report("Failed to truncate image: %s", strerror(-ret));
     }
