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https://issues.apache.org/jira/browse/HDFS-1788?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13050261#comment-13050261
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Bochun Bai commented on HDFS-1788:
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Thanks daryn, your reviews encourage me a lot.
I will rewrite the patch and follow your advises.
But I got some difficult while keeping PathData maximum compatible:
Adds lstat, leaving fs, stat, exists.
And fc should be added because HADOOP-6446. Further works should use
FileContext instead of FileSystem.
And lexists is requeired to identify broken links.
The problem is fc should be initialized in ctor like fs, whether it is
parameter or not, breaks compatible by requiring new parameter or throwing
exceptions.
If fc is not a field of PathData and initialized when item.lstat() is called.
RPC to NN will increased.
To satisfies both compatible and feature, I suggest create a object named
StatusData:
contains fc, lstat and string.
represent the link itself, not the real file.
when cat/tail/stat is called, lstat.symlink will be resolved recursively and
the real target is returned.
FileStatus is recursively, and StatusData is independent to link or not.
RPC to NN is decreased while listing a directory containing symlink.
stat/read/write overhead to the symlink is the same, but lazy-inited. It should
also improve GC activities to HADOOP-6732.
And I have noticed @eli created a serial issues about porting FileContext. I
will submit next patch to HADOOP-6424.
> FsShell ls: Show symlinks properties
> ------------------------------------
>
> Key: HDFS-1788
> URL: https://issues.apache.org/jira/browse/HDFS-1788
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: tools
> Reporter: Jonathan Eagles
> Assignee: John George
> Priority: Minor
> Attachments: HDFS-1788.patch
>
>
> ls FsShell command implementation has been consistent with the linux
> implementations of ls \-l. With the addition of symlinks, I would expect the
> ability to show file type 'd' for directory, '\-' for file, and 'l' for
> symlink. In addition, following the linkname entry for symlinks, I would
> expect the ability to show "\-> <link target>". In linux, the default is to
> the the properties of the link and not of the link target. In linux, '-L'
> option allows for the dereferencing of symlinks to show link target
> properties, but it is not the default.
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