[
https://issues.apache.org/jira/browse/HDFS-4140?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13493474#comment-13493474
]
Andy Isaacson commented on HDFS-4140:
-------------------------------------
(user error truncated comment)
... Opening {{O_TRUNC}} and then overwriting the file is a use case we can
support. Opening {{O_APPEND}} is supportable. Basically, we should provide
the same behavior as a standard POSIX filesystem unless we cannot, and return
an appropriate errno in those cases.
I haven't thought about it carefully, but {{flags |= O_APPEND}} doesn't seem
like it's going to provide completely correct semantics.
> fuse-dfs handles open(O_TRUNC) poorly
> -------------------------------------
>
> Key: HDFS-4140
> URL: https://issues.apache.org/jira/browse/HDFS-4140
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: fuse-dfs
> Affects Versions: 2.0.2-alpha
> Reporter: Andy Isaacson
> Assignee: Colin Patrick McCabe
> Attachments: HDFS-4140.003.patch
>
>
> fuse-dfs handles open(O_TRUNC) poorly.
> It is converted to multiple fuse operations. Those multiple fuse operations
> often fail (for example, calling fuse_truncate_impl() while a file is also
> open for write results in a "multiple writers!" exception.)
> One easy way to see the problem is to run the following sequence of shell
> commands:
> {noformat}
> ubuntu@ubu-cdh-0:~$ echo foo > /export/hdfs/tmp/a/t1.txt
> ubuntu@ubu-cdh-0:~$ ls -l /export/hdfs/tmp/a
> total 0
> -rw-r--r-- 1 ubuntu hadoop 4 Nov 1 15:21 t1.txt
> ubuntu@ubu-cdh-0:~$ hdfs dfs -ls /tmp/a
> Found 1 items
> -rw-r--r-- 3 ubuntu hadoop 4 2012-11-01 15:21 /tmp/a/t1.txt
> ubuntu@ubu-cdh-0:~$ echo bar > /export/hdfs/tmp/a/t1.txt
> ubuntu@ubu-cdh-0:~$ ls -l /export/hdfs/tmp/a
> total 0
> -rw-r--r-- 1 ubuntu hadoop 0 Nov 1 15:22 t1.txt
> ubuntu@ubu-cdh-0:~$ hdfs dfs -ls /tmp/a
> Found 1 items
> -rw-r--r-- 3 ubuntu hadoop 0 2012-11-01 15:22 /tmp/a/t1.txt
> {noformat}
--
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
