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https://issues.apache.org/jira/browse/HDFS-4750?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13642000#comment-13642000
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Brandon Li commented on HDFS-4750:
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{quote}This is very semantically wrong. If another client appended to the file
in the interim, the file position should not implicitly move to the end of the
file.
{quote}
When the stream is closed, the file size is updated in HDFS. Before it's
closed, the same client still holds the lease.
{quote}Assuming the proposed approach is otherwise valid: when the client
attempts to write again via append, it should throw an exception if the file
size is greater than the client's current position in the stream. Even that
breaks POSIX semantics, but it's "less wrong" by not causing the potential for
garbled data.{quote}
If the file is appended by another client, the first client's new write before
the file's <EOF> becomes random write and would fail with exception. What
breaks POSIX semantic here is that random write is not support.
> Support NFSv3 interface to HDFS
> -------------------------------
>
> Key: HDFS-4750
> URL: https://issues.apache.org/jira/browse/HDFS-4750
> Project: Hadoop HDFS
> Issue Type: New Feature
> Affects Versions: 3.0.0
> Reporter: Brandon Li
> Assignee: Brandon Li
> Attachments: HADOOP-NFS-Proposal.pdf
>
>
> Access HDFS is usually done through HDFS Client or webHDFS. Lack of seamless
> integration with client’s file system makes it difficult for users and
> impossible for some applications to access HDFS. NFS interface support is one
> way for HDFS to have such easy integration.
> This JIRA is to track the NFS protocol support for accessing HDFS. With HDFS
> client, webHDFS and the NFS interface, HDFS will be easier to access and be
> able support more applications and use cases.
> We will upload the design document and the initial implementation.
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