[
https://issues.apache.org/jira/browse/HDFS-6981?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14121921#comment-14121921
]
Haohui Mai commented on HDFS-6981:
----------------------------------
{code}
+ /**
+ * Current layout version for DataNode.
+ * Please see {@link DataNodeLayoutVersion.Feature} on adding new layout
version.
+ */
+ public static int getDatanodeLayoutVersion() {
+ return DataNodeLayoutVersion.getCurrentLayoutVersion();
+ }
{code}
To avoid the refactoring, you can use reflection to change the value of
{{DATANODE_LAYOUT_VERSION}} to inject new layout version in the test. This
should simplify the patch quite a bit.
{code}
/**
+ * If the DN layout version has been overridden
+ * @param map
+ * @return
+ */
+ @Override
+ public boolean versionSupportsFederation(
+ Map<Integer, SortedSet<LayoutVersion.LayoutFeature>> map,
+ int layoutVersionIn) {
+ return DataNodeLayoutVersion.supports(
+ LayoutVersion.Feature.FEDERATION, layoutVersionIn);
+ }
+
{code}
It does not seem necessary. Is it related to the above issue?
> DN upgrade with layout version change should not use trash
> ----------------------------------------------------------
>
> Key: HDFS-6981
> URL: https://issues.apache.org/jira/browse/HDFS-6981
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: datanode
> Affects Versions: 3.0.0
> Reporter: James Thomas
> Assignee: Arpit Agarwal
> Attachments: HDFS-6981.01.patch, HDFS-6981.02.patch
>
>
> Post HDFS-6800, we can encounter the following scenario:
> # We start with DN software version -55 and initiate a rolling upgrade to
> version -56
> # We delete some blocks, and they are moved to trash
> # We roll back to DN software version -55 using the -rollback flag – since we
> are running the old code (prior to this patch), we will restore the previous
> directory but will not delete the trash
> # We append to some of the blocks that were deleted in step 2
> # We then restart a DN that contains blocks that were appended to – since the
> trash still exists, it will be restored at this point, the appended-to blocks
> will be overwritten, and we will lose the appended data
> So I think we need to avoid writing anything to the trash directory if we
> have a previous directory.
> Thanks to [~james.thomas] for reporting this.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
