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https://issues.apache.org/jira/browse/HDFS-2712?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13180737#comment-13180737
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Daryn Sharp commented on HDFS-2712:
-----------------------------------
Interesting. HADOOP-1869 is long and a bit unclear. A number of people did
advocate posix compliance. My reading is there was concern over lots of atime
updates for directories, however posix just requires atime to set at creation
time. Using a directory's mtime in place of atime, thus removing atime, really
violates posix. Banning setTimes on a directory also violates posix.
Breaking all these posix semantics could spell trouble for filesystems that do
want to adhere to posix, including FUSE implementations.
As a related aside: For performance reasons, I can see not updating a
directory's mtime when its contents are altered, but why aren't we updating
mtime when the owner/group/permissions are changed? In which case atime
becomes important for a directory.
> setTimes should support only for files and move the atime field down to
> iNodeFile.
> ----------------------------------------------------------------------------------
>
> Key: HDFS-2712
> URL: https://issues.apache.org/jira/browse/HDFS-2712
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: name-node
> Affects Versions: 0.23.0, 0.24.0
> Reporter: Uma Maheswara Rao G
> Assignee: Uma Maheswara Rao G
> Attachments: HDFS-2712.patch
>
>
> After the dicussion in HDFS-2436, unsupported behaviour for setTimes was
> intentional (HADOOP-1869).
> But current INode structure hierarchy seems, it supports atime for
> directories also. But as per HADOOP-1869, we are supporting only for files.
> To avoid the confusions, we can move the atime fields to INodeFile as we
> planned to support setTimes only for files. And also restrict the support for
> setTimes on directories ( which is implemented with HDFS-2436 ).
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