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https://issues.apache.org/jira/browse/HDFS-7678?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14527716#comment-14527716
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Jing Zhao commented on HDFS-7678:
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Thanks for the great work, Zhe! I have not finished my review yet, but looks
like the latest 008 patch will fail TestDFSStripedInputStream (and it passed
the pread part but failed in the stateful read part)? Besides, for
{{ReadPortion}}'s public fields, I changed them to private because they both
are not declared as final and can be modified outside. Thus feels like to
restrict the modification going through the setters will make it easier to
track. But not feeling very strong on this.
Another quick comment is, the following change looks incorrect to me. For
example, if {{blkStartOffset - lb.getStartOffset()}} points to cellSize * 10
inside of the block group, we should read from the 5th data block instead of
2nd.
{code}
int idx = (int) (((blkStartOffset - lb.getStartOffset()) / cellSize)
- % dataBlkNum);
+ % (dataBlkNum + parityBlkNum));
{code}
Will try to finish the review and post comments later today.
> Erasure coding: DFSInputStream with decode functionality
> --------------------------------------------------------
>
> Key: HDFS-7678
> URL: https://issues.apache.org/jira/browse/HDFS-7678
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Affects Versions: HDFS-7285
> Reporter: Li Bo
> Assignee: Zhe Zhang
> Attachments: BlockGroupReader.patch, HDFS-7678-HDFS-7285.002.patch,
> HDFS-7678-HDFS-7285.003.patch, HDFS-7678-HDFS-7285.004.patch,
> HDFS-7678-HDFS-7285.005.patch, HDFS-7678-HDFS-7285.006.patch,
> HDFS-7678-HDFS-7285.007.patch, HDFS-7678-HDFS-7285.008.patch,
> HDFS-7678.000.patch, HDFS-7678.001.patch
>
>
> A block group reader will read data from BlockGroup no matter in striping
> layout or contiguous layout. The corrupt blocks can be known before
> reading(told by namenode), or just be found during reading. The block group
> reader needs to do decoding work when some blocks are found corrupt.
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