src/java.base/unix/classes/sun/nio/fs/UnixFileStore.java

@@ -124,10 +124,16 @@
        UnixFileStoreAttributes attrs = readAttributes();
        return attrs.blockSize() * attrs.availableBlocks();
     }
 
     @Override
+    public int getBlockSize() throws IOException {
+       UnixFileStoreAttributes attrs = readAttributes();
+       return (int)attrs.blockSize();
+    }
+
+    @Override
     public long getUnallocatedSpace() throws IOException {
         UnixFileStoreAttributes attrs = readAttributes();
         return attrs.blockSize() * attrs.freeBlocks();
     }