diff --git a/block/vdi.c b/block/vdi.c
index 2b4d2c2..b990bbc 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -827,7 +827,7 @@ static int vdi_create(const char *filename, QEMUOptionParameter *options)
         return -errno;
     }
 
-    blocks = bytes / block_size;
+    blocks = (bytes + block_size - 1) / block_size;
     bmap_size = blocks * sizeof(uint32_t);
     bmap_size = ((bmap_size + SECTOR_SIZE - 1) & ~(SECTOR_SIZE -1));