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https://issues.apache.org/jira/browse/HDFS-3335?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Colin Patrick McCabe updated HDFS-3335:
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Attachment: HDFS-3335.001.patch
Add patch for trunk.
* Always check for corruption at the end of the log, unless we are reading the
last megabyte of an unfinalized edit log.
* Create constant for PREALLOCATION_LENGTH. Use it everywhere we were
previously copying-and-pasting the integer.
* FSEditLogLoader: log any exceptions that we get when reading the edit log.
* FSEditLogOp: add verifyEndOfLog
* FSEditLogOp: restrict serialized FSEditLogOp operations to a megabyte in size.
Previously, I was trying to avoid having a hard limit on edit log operation
size by doing
{code}
in.mark(in.available())
{code}
However, this is not valid. in.available() does NOT reflect how many bytes
remain in the stream-- it just reflects the number that can be read without
blocking, a number which may or may not be related to the amount left.
> check for edit log corruption at the end of the log
> ---------------------------------------------------
>
> Key: HDFS-3335
> URL: https://issues.apache.org/jira/browse/HDFS-3335
> Project: Hadoop HDFS
> Issue Type: Improvement
> Affects Versions: 0.23.0
> Reporter: Colin Patrick McCabe
> Assignee: Colin Patrick McCabe
> Attachments: HDFS-3335-b1.001.patch, HDFS-3335-b1.002.patch,
> HDFS-3335-b1.003.patch, HDFS-3335.001.patch
>
>
> Even after encountering an OP_INVALID, we should check the end of the edit
> log to make sure that it contains no more edits.
> This will catch things like rare race conditions or log corruptions that
> would otherwise remain undetected. They will got from being silent data loss
> scenarios to being cases that we can detect and fix.
> Using recovery mode, we can choose to ignore the end of the log if necessary.
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