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https://issues.apache.org/jira/browse/HDFS-7682?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14308012#comment-14308012
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Jing Zhao commented on HDFS-7682:
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Thanks Charles. My main concern is that the patch is just a partial fix, since
it cannot cover the case that the file is snapshotted but still being written.
bq. In other words, the behavior for non-snapshotted files that are still open
(and possibly being appended to) is not changed by this patch, only that of
snapshotted files, for which isLastBlockComplete() is a valid check.
The behavior for snapshotted files that are still open also have not been
changed.
Actually for a snapshotted file, {{blockLocations.getFileLength}} should equal
to the file length explicitly recorded in the snapshot diff. If there is not
such length recorded, {{blockLocations.getFileLength}} should be the current
file length including the last uc block's length (please read the current code
to confirm). In that case, the check condition should be "if the src is a
snapshot path", and we should use {{blockLocations.getFileLength}} as the limit.
> {{DistributedFileSystem#getFileChecksum}} of a snapshotted file includes
> non-snapshotted content
> ------------------------------------------------------------------------------------------------
>
> Key: HDFS-7682
> URL: https://issues.apache.org/jira/browse/HDFS-7682
> Project: Hadoop HDFS
> Issue Type: Bug
> Affects Versions: 2.7.0
> Reporter: Charles Lamb
> Assignee: Charles Lamb
> Attachments: HDFS-7682.000.patch, HDFS-7682.001.patch,
> HDFS-7682.002.patch
>
>
> DistributedFileSystem#getFileChecksum of a snapshotted file includes
> non-snapshotted content.
> The reason why this happens is because DistributedFileSystem#getFileChecksum
> simply calculates the checksum of all of the CRCs from the blocks in the
> file. But, in the case of a snapshotted file, we don't want to include data
> in the checksum that was appended to the last block in the file after the
> snapshot was taken.
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