修改hadoop FileUtil.java，解决权限检查的问题

15/01/30 10:08:17 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
15/01/30 10:08:17 ERROR security.UserGroupInformation: PriviledgedActionException as:zhangchao3 cause:java.io.IOException: Failed to set permissions of path: \tmp\hadoop-zhangchao3\mapred\staging\zhangchao3502228304\.staging to 0700
Exception in thread "main" java.io.IOException: Failed to set permissions of path: \tmp\hadoop-zhangchao3\mapred\staging\zhangchao3502228304\.staging to 0700
at org.apache.hadoop.fs.FileUtil.checkReturnValue(FileUtil.java:689)
at org.apache.hadoop.fs.FileUtil.setPermission(FileUtil.java:662)
at org.apache.hadoop.fs.RawLocalFileSystem.setPermission(RawLocalFileSystem.java:509)
at org.apache.hadoop.fs.RawLocalFileSystem.mkdirs(RawLocalFileSystem.java:344)
at org.apache.hadoop.fs.FilterFileSystem.mkdirs(FilterFileSystem.java:189)
at org.apache.hadoop.mapreduce.JobSubmissionFiles.getStagingDir(JobSubmissionFiles.java:116)
at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:856)
at org.apache.hadoop.mapred.JobClient$2.run(JobClient.java:850)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)
at org.apache.hadoop.mapred.JobClient.submitJobInternal(JobClient.java:850)
at org.apache.hadoop.mapreduce.Job.submit(Job.java:500)
at org.apache.hadoop.mapreduce.Job.waitForCompletion(Job.java:530)
at org.apache.hadoop.examples.WordCount.main(WordCount.java:68)

据提示信息，可以看到，这个异常是org.apache.hadoop.fs.FileUtil.checkReturnValue(FileUtil.java:689)行抛出来的，把这个位置的源代码贴出来，研究一下：

private static void checkReturnValue(boolean rv, File p,
FsPermission permission
) throws IOException {
if (!rv) {
throw new IOException("Failed to set permissions of path: " + p +
" to " +
String.format("%04o", permission.toShort()));
}
}

把If语句块注释

private static void checkReturnValue(boolean rv, File p, FsPermission permission)
throws IOException
{}