[jira] [Commented] (HADOOP-16378) RawLocalFileStatus throws exception if a file is created and deleted quickly

["Steve Loughran (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-16378?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16866669#comment-16866669 ] 

Steve Loughran commented on HADOOP-16378:
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I'd prefer moving off shell entirely and into the fs APIs, either java or hadoop native. Doesn't it already drop to some native lib if its available?

> RawLocalFileStatus throws exception if a file is created and deleted quickly
> ----------------------------------------------------------------------------
>
>                 Key: HADOOP-16378
>                 URL: https://issues.apache.org/jira/browse/HADOOP-16378
>             Project: Hadoop Common
>          Issue Type: Bug
>          Components: fs
>    Affects Versions: 3.3.0
>         Environment: Ubuntu 18.04, Hadoop 2.7.3 (Though this problem exists on later versions of Hadoop as well), Java 8 ( + Java 11).
>            Reporter: K S
>            Priority: Critical
>
> Bug occurs when NFS creates temporary ".nfs*" files as part of file moves and accesses. If this file is deleted very quickly after being created, a RuntimeException is thrown. The root cause is in the loadPermissionInfo method in org.apache.hadoop.fs.RawLocalFileSystem. To get the permission info, it first does
>  
> {code:java}
> ls -ld{code}
>  and then attempts to get permissions info about each file. If a file disappears between these two steps, an exception is thrown.
> *Reproduction Steps:*
> An isolated way to reproduce the bug is to run FileInputFormat.listStatus over and over on the same dir that we’re creating those temp files in. On Ubuntu or any other Linux-based system, this should fail intermittently
> *Fix:*
> One way in which we managed to fix this was to ignore the exception being thrown in loadPemissionInfo() if the exit code is 1 or 2. Alternatively, it's possible that turning "useDeprecatedFileStatus" off in RawLocalFileSystem would fix this issue, though we never tested this, and the flag was implemented to fix -HADOOP-9652-. Could also fix in conjunction with HADOOP-8772.
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