[jira] [Updated] (HDFS-10458) getFileEncryptionInfo should return quickly for non-encrypted cluster

["Zhe Zhang (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HDFS-10458?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Zhe Zhang updated HDFS-10458:
-----------------------------
    Attachment: HDFSA-10458.01.patch

Thanks [~shv] for the review. Attaching new patch to take the suggestion. I think it is a good idea to add the check in {{getEncryptionZoneForPath}}.

However, for uses in {{startFile}} etc., we should be more careful about race conditions. Therefore I added a boolean variable that can only be turned on once (can never be turned off). It is turned on *before* adding any encryption zone so it is safe to assume no EZ exists if the variable is false.

> getFileEncryptionInfo should return quickly for non-encrypted cluster
> ---------------------------------------------------------------------
>
>                 Key: HDFS-10458
>                 URL: https://issues.apache.org/jira/browse/HDFS-10458
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: encryption, namenode
>    Affects Versions: 2.6.0
>            Reporter: Zhe Zhang
>            Assignee: Zhe Zhang
>         Attachments: HDFS-10458.00.patch, HDFSA-10458.01.patch
>
>
> {{FSDirectory#getFileEncryptionInfo}} always acquires {{readLock}} and checks if the path belongs to an EZ. For a busy system with potentially many listing operations, this could cause locking contention.
> I think we should add a call {{EncryptionZoneManager#hasEncryptionZone()}} to return whether the system has any EZ. If no EZ at all, {{getFileEncryptionInfo}} should return null without {{readLock}}.
> If {{hasEncryptionZone}} is only used in the above scenario, maybe itself doesn't need a {{readLock}} -- if the system doesn't have any EZ when {{getFileEncryptionInfo}} is called on a path, it means the path cannot be encrypted.



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