/** Runnable responsible for heartbeating and registration with master. */
和master节点的心跳任务
private BlockMasterSync mBlockMasterSync;/** Runnable responsible for fetching pinlist from master. */
获取master pin列表的任务
private PinListSync mPinListSync;/** Runnable responsible for clean up potential zombie sessions. */
private SessionCleaner mSessionCleaner;/** Client for all block master communication. */
与block master通讯
private final BlockMasterClient mBlockMasterClient;
/*** Block master clients. commitBlock is the only reason to keep a pool of block master clients* on each worker. We should either improve our RPC model in the master or get rid of the* necessity to call commitBlock in the workers.*/
private final BlockMasterClientPool mBlockMasterClientPool;/** Client for all file system master communication. */
与file system交互的客户端
private final FileSystemMasterClient mFileSystemMasterClient;/** Block store delta reporter for master heartbeat. */
报告者
private BlockHeartbeatReporter mHeartbeatReporter;
/** Metrics reporter that listens on block events and increases metrics counters. */
报告者
private BlockMetricsReporter mMetricsReporter;
/** Session metadata, used to keep track of session heartbeats. */
private Sessions mSessions;
/** Block Store manager. */
mBlockStore是TieredBlockStore，为多级存储block存储管理器
private BlockStore mBlockStore;
private WorkerNetAddress mAddress;/** The under file system block store. */
ufs管理器
private final UnderFileSystemBlockStore mUnderFileSystemBlockStore;/*** The worker ID for this worker. This is initialized in {@link #start(WorkerNetAddress)} and may* be updated by the block sync thread if the master requests re-registration.*/
private AtomicReference<Long> mWorkerId;

//申请策略接口
private final Allocator mAllocator;
//驱逐策略接口
private final Evictor mEvictor;private final Set<Long> mPinnedInodes = new HashSet<>();