diff --git a/block/parallels.c b/block/parallels.c
index 3c22dfdc9d..9594d84978 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -421,7 +421,6 @@ static int coroutine_fn parallels_co_check(BlockDriverState *bs,
     int ret;
     uint32_t i;
     bool flush_bat = false;
-    int cluster_size = s->tracks << BDRV_SECTOR_BITS;
 
     size = bdrv_getlength(bs->file->bs);
     if (size < 0) {
@@ -472,7 +471,7 @@ static int coroutine_fn parallels_co_check(BlockDriverState *bs,
             high_off = off;
         }
 
-        if (prev_off != 0 && (prev_off + cluster_size) != off) {
+        if (prev_off != 0 && (prev_off + s->cluster_size) != off) {
             res->bfi.fragmented_clusters++;
         }
         prev_off = off;
@@ -487,10 +486,10 @@ static int coroutine_fn parallels_co_check(BlockDriverState *bs,
         }
     }
 
-    res->image_end_offset = high_off + cluster_size;
+    res->image_end_offset = high_off + s->cluster_size;
     if (size > res->image_end_offset) {
         int64_t count;
-        count = DIV_ROUND_UP(size - res->image_end_offset, cluster_size);
+        count = DIV_ROUND_UP(size - res->image_end_offset, s->cluster_size);
         fprintf(stderr, "%s space leaked at the end of the image %" PRId64 "\n",
                 fix & BDRV_FIX_LEAKS ? "Repairing" : "ERROR",
                 size - res->image_end_offset);
@@ -771,6 +770,7 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
         ret = -EFBIG;
         goto fail;
     }
+    s->cluster_size = s->tracks << BDRV_SECTOR_BITS;
 
     s->bat_size = le32_to_cpu(ph.bat_entries);
     if (s->bat_size > INT_MAX / sizeof(uint32_t)) {
diff --git a/block/parallels.h b/block/parallels.h
index 5aa101cfc8..9a9209e320 100644
--- a/block/parallels.h
+++ b/block/parallels.h
@@ -79,6 +79,7 @@ typedef struct BDRVParallelsState {
     ParallelsPreallocMode prealloc_mode;
 
     unsigned int tracks;
+    unsigned int cluster_size;
 
     unsigned int off_multiplier;
     Error *migration_blocker;