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https://issues.apache.org/jira/browse/HDFS-12202?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16107838#comment-16107838
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Chris Douglas commented on HDFS-12202:
--------------------------------------
This is a pretty narrow use case. As [~asuresh] points out, most would be
covered by a server-side policy that either a) applies, but does not return
augmented plugin state for particular users or b) filters out properties
applied by the plugin. Implementing (b) only requires a modification to distcp.
If Sentry/Ranger/etc. don't put their attributes in a namespace-like schema so
(b) is difficult to implement, then a server-side policy is still preferable.
Extending {{FileSystem}} is a very hard sell, since it would also add this flag
to the protocol. Not only would this approach not work for old clusters, it
would silently return the unfiltered results. Moreover, every FileSystem other
than HDFS wouldn't support this. Are there other use cases?
> Provide new set of FileSystem API to bypass external attribute provider
> -----------------------------------------------------------------------
>
> Key: HDFS-12202
> URL: https://issues.apache.org/jira/browse/HDFS-12202
> Project: Hadoop HDFS
> Issue Type: New Feature
> Components: hdfs, hdfs-client
> Reporter: Yongjun Zhang
> Assignee: Yongjun Zhang
>
> HDFS client uses
> {code}
> /**
> * Return a file status object that represents the path.
> * @param f The path we want information from
> * @return a FileStatus object
> * @throws FileNotFoundException when the path does not exist
> * @throws IOException see specific implementation
> */
> public abstract FileStatus getFileStatus(Path f) throws IOException;
> /**
> * List the statuses of the files/directories in the given path if the path
> is
> * a directory.
> * <p>
> * Does not guarantee to return the List of files/directories status in a
> * sorted order.
> * <p>
> * Will not return null. Expect IOException upon access error.
> * @param f given path
> * @return the statuses of the files/directories in the given patch
> * @throws FileNotFoundException when the path does not exist
> * @throws IOException see specific implementation
> */
> public abstract FileStatus[] listStatus(Path f) throws
> FileNotFoundException,
> IOException;
> {code}
> to get FileStatus of files.
> When external attribute provider (INodeAttributeProvider) is enabled for a
> cluster, the external attribute provider is consulted to get back some
> relevant info (including ACL, group etc) and returned back in FileStatus,
> There is a problem here, when we use distcp to copy files from srcCluster to
> tgtCluster, if srcCluster has external attribute provider enabled, the data
> we copied would contain data from attribute provider, which we may not want.
> Create this jira to add a new set of interface for distcp to use, so that
> distcp can copy HDFS data only and bypass external attribute provider data.
> The new set API would look like
> {code}
> /**
> * Return a file status object that represents the path.
> * @param f The path we want information from
> * @param bypassExtAttrProvider if true, bypass external attr provider
> * when it's in use.
> * @return a FileStatus object
> * @throws FileNotFoundException when the path does not exist
> * @throws IOException see specific implementation
> */
> public FileStatus getFileStatus(Path f,
> final boolean bypassExtAttrProvider) throws IOException;
> /**
> * List the statuses of the files/directories in the given path if the path
> is
> * a directory.
> * <p>
> * Does not guarantee to return the List of files/directories status in a
> * sorted order.
> * <p>
> * Will not return null. Expect IOException upon access error.
> * @param f
> * @param bypassExtAttrProvider if true, bypass external attr provider
> * when it's in use.
> * @return
> * @throws FileNotFoundException
> * @throws IOException
> */
> public FileStatus[] listStatus(Path f,
> final boolean bypassExtAttrProvider) throws FileNotFoundException,
> IOException;
> {code}
> So when bypassExtAttrProvider is true, external attribute provider will be
> bypassed.
> Thanks.
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