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https://issues.apache.org/jira/browse/HADOOP-8849?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13556491#comment-13556491
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Robert Joseph Evans commented on HADOOP-8849:
---------------------------------------------

I just kicked the build again because the first time trunk was broken.  The new 
patch looks fine to me +1. I'll check it in.
                
> FileUtil#fullyDelete should grant the target directories +rwx permissions 
> before trying to delete them
> ------------------------------------------------------------------------------------------------------
>
>                 Key: HADOOP-8849
>                 URL: https://issues.apache.org/jira/browse/HADOOP-8849
>             Project: Hadoop Common
>          Issue Type: Improvement
>    Affects Versions: 3.0.0, 2.0.3-alpha, 0.23.6
>            Reporter: Ivan A. Veselovsky
>            Assignee: Ivan A. Veselovsky
>            Priority: Minor
>         Attachments: HADOOP-8849-trunk--5.patch, HADOOP-8849-vs-trunk-4.patch
>
>
> 2 improvements are suggested for implementation of methods 
> org.apache.hadoop.fs.FileUtil.fullyDelete(File) and 
> org.apache.hadoop.fs.FileUtil.fullyDeleteContents(File):
>  
> 1) We should grant +rwx permissions the target directories before trying to 
> delete them.
> The mentioned methods fail to delete directories that don't have read or 
> execute permissions.
> Actual problem appears if an hdfs-related test is timed out (with a short 
> timeout like tens of seconds), and the forked test process is killed, some 
> directories are left on disk that are not readable and/or executable. This 
> prevents next tests from being executed properly because these directories 
> cannot be deleted with FileUtil#fullyDelete(), so many subsequent tests fail. 
> So, its recommended to grant the read, write, and execute permissions the 
> directories whose content is to be deleted.
> 2) Generic reliability improvement: we shouldn't rely upon File#delete() 
> return value, use File#exists() instead. 
> FileUtil#fullyDelete() uses return value of method java.io.File#delete(), but 
> this is not reliable because File#delete() returns true only if the file was 
> deleted as a result of the #delete() method invocation. E.g. in the following 
> code
> if (f.exists()) { // 1
>   return f.delete(); // 2
> }
> if the file f was deleted by another thread or process between calls "1" and 
> "2", this fragment will return "false", while the file f does not exist upon 
> the method return.
> So, better to write
> if (f.exists()) {
>   f.delete();
>   return !f.exists();
> }

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