[HDFS-5341] Reduce fsdataset lock duration during directory scanning.

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.3.0
• Component/s: datanode
• Hadoop Flags: Reviewed
• Assignee: qus-jiawei
• Reporter: qus-jiawei
• Created: 11/Oct/13 02:33
• Updated: 03/Sep/14 23:34
• Resolved: 23/Oct/13 21:34

Description

When DirectoryScanner doing the scan function, it holding the dataset to diff the block info between memory and disk.But it do a lot of disk operation because it call the file's getlength funciton.

Once the dataset is locked,heartbeat thread and all DataXceiver thread would be blocked.

So,such disk operation should move to the async disk scan