org.apache.hadoop.hdfs.server.datanode
Interfaces 
FSDatasetInterface
Replica
Classes 
DataNode
DatanodeJspHelper
DataStorage
DirectoryScanner
FSDataset
FSDatasetInterface.BlockInputStreams
FSDatasetInterface.BlockWriteStreams
FSDatasetInterface.MetaDataInputStream
ReplicaInfo
UpgradeObjectDatanode
Exceptions 
ReplicaNotFoundException