[
https://issues.apache.org/jira/browse/HADOOP-9507?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13720163#comment-13720163
]
Chris Nauroth commented on HADOOP-9507:
---------------------------------------
{quote}
It is closest to the existing behavior on non-Windows platforms
{quote}
Just to elaborate on this a bit, talking with Arpit made me realize that
version 2 of the patch (copy-delete) would have accidentally introduced new
behavior on Linux. Currently on Linux, a rename crossing file systems would
fail in {{File#renameTo}} and then fall through to {{FileUtil#copy}}. In
version 2, we would instead trigger the copy-delete logic, which would have a
different result.
The goal of this issue was to provide a match to this method's existing
behavior on platforms where {{File#renameTo}} behaves differently, like
Windows. Therefore, I'm now in favor of version 3 of the patch
(delete-rename), not only for performance but also for correctness.
I'll provide new patches shortly to address Arpit's final comment.
> LocalFileSystem rename() is broken in some cases when destination exists
> ------------------------------------------------------------------------
>
> Key: HADOOP-9507
> URL: https://issues.apache.org/jira/browse/HADOOP-9507
> Project: Hadoop Common
> Issue Type: Bug
> Components: fs
> Affects Versions: 3.0.0, 1-win, 2.1.0-beta, 1.3.0
> Reporter: Mostafa Elhemali
> Assignee: Chris Nauroth
> Priority: Minor
> Attachments: HADOOP-9507-branch-1.1.patch,
> HADOOP-9507-branch-1.3.patch, HADOOP-9507-branch-1-win.1.patch,
> HADOOP-9507-branch-1-win.3.patch, HADOOP-9507.branch-1-win.patch,
> HADOOP-9507-trunk.1.patch, HADOOP-9507-trunk.2.patch,
> HADOOP-9507-trunk.3.patch
>
>
> The rename() method in RawLocalFileSystem uses FileUtil.copy() without
> realizing that FileUtil.copy() has a special behavior that if you're copying
> /foo to /bar and /bar exists and is a directory, it'll copy /foo inside /bar
> instead of overwriting it, which is not what rename() wants. So you end up
> with weird behaviors like in this repro:
> {code}
> c:
> cd \
> md Foo
> md Bar
> md Foo\X
> md Bar\X
> hadoop fs -mv file:///c:/Foo file:///c:/Bar
> {code}
> At the end of this, you would expect to find only Bar\X, but you instead find
> Bar\X\X.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
