We need to fix a case where zero-copy or no-checksum reads are not allowed even when the block is cached. The case is when the block is cached before the REQUEST_SHORT_CIRCUIT_FDS operation begins. In this case, DataXceiver needs to consult the ShortCircuitRegistry to see if the block is cached, rather than relying on a callback.
- Hadoop HDFS
- HDFS-5182 BlockReaderLocal must allow zero-copy reads only when the DN believes it's valid
- HDFS-6086