Shuyan Zhang created HDFS-17150:
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Summary: EC: Fix the bug of failed lease recovery.
Key: HDFS-17150
URL: https://issues.apache.org/jira/browse/HDFS-17150
Project: Hadoop HDFS
Issue Type: Bug
Reporter: Shuyan Zhang
If the client crashes without writing the minimum number of internal blocks
required by the EC policy, the lease recovery process for the corresponding
unclosed file may continue to fail. Taking RS(6,3) policy as an example, the
timeline is as follows:
1. The client writes some data to only 5 datanodes;
2. Client crashes;
3. NN fails over;
4. Now the result of `uc.getNumExpectedLocations()` completely depends on block
report, and there are 5 datanodes reporting internal blocks;
5. When the lease expires hard limit, NN issues a block recovery command;
6. The datanode checks the command and finds that the number of internal blocks
is insufficient, resulting in an error and recovery failure;
7. The lease expires hard limit again, and NN issues a block recovery command
again, but the recovery fails again......
When the number of internal blocks written by the client is less than 6, the
block group is actually unrecoverable. We should equate this situation to the
case where the number of replicas is 0 when processing replica files, i.e.,
directly remove the last block group and close the file.
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