Add binding.close to fs.readFile

lib/fs.js

@@ -53,12 +53,17 @@ fs.readFile = function (path, encoding_, callback) {
       function doRead() {
         // position is offset or null so we can read files on unseekable mediums
         binding.read(fd, buffer, offset, size - offset, offset || null, function (err, amount) {
-          if (err) { callback(err); return; }
+          if (err) {
+            callback(err);
+            binding.close(fd);
+            return;
+          }
           if (amount + offset < size) {
             offset += amount;
             doRead();
             return;
           }
+          binding.close(fd);
           if (encoding) {
             try {
               callback(null, buffer.toString(encoding));