Fix tests that rely on rootdev specifying a real block device.

client/site_tests/hardware_StorageFio/hardware_StorageFio.py

 # Copyright (c) 2009 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import logging, os, re
 
 from autotest_lib.client.bin import test, utils
 from autotest_lib.client.common_lib import error
 
 class hardware_StorageFio(test.test):
@@ skipping 20 matching lines @@
         utils.make(make='%s %s make' % (var_ldflags, var_cflags))
 
 
     def __find_free_root_partition(self):
         """Locate the spare root partition that we didn't boot off"""
 
         spare_root_map = {
             '3': '5',
             '5': '3',
         }
-        rootdev = utils.system_output('rootdev')
+        rootdev = utils.system_output('rootdev -s')
         spare_root = rootdev[:-1] + spare_root_map[rootdev[-1]]
         self.__filename = spare_root
 
 
     def __get_file_size(self):
         """Return the size in bytes of the device pointed to by __filename"""
 
         device = os.path.basename(self.__filename)
         for line in file('/proc/partitions'):
             try:
@@ skipping 148 matching lines @@
             results[units + '_' + test] = result[metric]
 
         # Output keys relevent to the performance, larger filesize will run
         # slower, and sda5 should be slightly slower than sda3 on a rotational
         # disk
         self.write_test_keyval({'filesize': self.__filesize,
                                 'filename': self.__filename,
                                 'device': self.__description})
         logging.info('Device Description: %s' % self.__description)
         self.write_perf_keyval(results)