parallels: Fix image_end_offset and data_end after out-of-image check

Set data_end to the end of the last cluster inside the image. In such a
way we can be sure that corrupted offsets in the BAT can't affect on the
image size. If there are no allocated clusters set image_end_offset by
data_end.

Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Message-Id: <20230424093147.197643-4-alexander.ivanov@virtuozzo.com>
Reviewed-by: Hanna Czenczek <hreitz@redhat.com>
Signed-off-by: Hanna Czenczek <hreitz@redhat.com>

block/parallels.c

@@ -490,7 +490,13 @@ parallels_co_check(BlockDriverState *bs, BdrvCheckResult *res,
         }
     }
 
-    res->image_end_offset = high_off + s->cluster_size;
+    if (high_off == 0) {
+        res->image_end_offset = s->data_end << BDRV_SECTOR_BITS;
+    } else {
+        res->image_end_offset = high_off + s->cluster_size;
+        s->data_end = res->image_end_offset >> BDRV_SECTOR_BITS;
+    }
+
     if (size > res->image_end_offset) {
         int64_t count;
         count = DIV_ROUND_UP(size - res->image_end_offset, s->cluster_size);