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https://issues.apache.org/jira/browse/HDFS-6984?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16002129#comment-16002129
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Andrew Wang commented on HDFS-6984:
-----------------------------------
Thanks again for the continued work here Chris, I want to get this in as badly
as you. I spent a little more time looking at the patch, and I'm comfortable
with {{HdfsFileStatus extends FileStatus}} once we make sure symlinks are
treated opaquely.
Symlinks:
* I saw three calls to HdfsFileStatus#getSymlink: FSNamesystem#logAuditEvent,
NNRpcServer#getLinkTarget, JsonUtil#toJsonMap. I think the latter two should be
calling {{getSymlinkBytes}} for opacity.
* We should add a warning to HdfsFileStatus#getSymlink about handling symlink
targets opaquely, for future coders.
The rest:
{quote}
Here is the relevant line. It's consistent with the documentation- that is the
FsPermission[Extension] for that path- but including the flag bits in the
AclStatus permission field looks more like an accident of the implementation,
not part of its intended API.
{quote}
Good catch. I see you removed this already in the 009 patch, agree that it
looks like an accident.
I'm convinced by the rest. Documenting the other pending issues here for
completeness:
* Any additional checking for symlink target opacity and conversion to a Path.
I only checked usages when it's a {{HdfsFileStatus}}, not usages of the base
{{FileStatus}} method.
* Snapshots potentially not working with EC or encryption? If so, this might be
more broadly an xattrs+snapshots bug.
* Backwards compatibility by still setting the permission bits for old clients.
> In Hadoop 3, make FileStatus serialize itself via protobuf
> ----------------------------------------------------------
>
> Key: HDFS-6984
> URL: https://issues.apache.org/jira/browse/HDFS-6984
> Project: Hadoop HDFS
> Issue Type: Improvement
> Affects Versions: 3.0.0-alpha1
> Reporter: Colin P. McCabe
> Assignee: Colin P. McCabe
> Labels: BB2015-05-TBR
> Attachments: HDFS-6984.001.patch, HDFS-6984.002.patch,
> HDFS-6984.003.patch, HDFS-6984.004.patch, HDFS-6984.005.patch,
> HDFS-6984.006.patch, HDFS-6984.007.patch, HDFS-6984.008.patch,
> HDFS-6984.009.patch, HDFS-6984.nowritable.patch
>
>
> FileStatus was a Writable in Hadoop 2 and earlier. Originally, we used this
> to serialize it and send it over the wire. But in Hadoop 2 and later, we
> have the protobuf {{HdfsFileStatusProto}} which serves to serialize this
> information. The protobuf form is preferable, since it allows us to add new
> fields in a backwards-compatible way. Another issue is that already a lot of
> subclasses of FileStatus don't override the Writable methods of the
> superclass, breaking the interface contract that read(status.write) should be
> equal to the original status.
> In Hadoop 3, we should just make FileStatus serialize itself via protobuf so
> that we don't have to deal with these issues. It's probably too late to do
> this in Hadoop 2, since user code may be relying on the existing FileStatus
> serialization there.
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