[HDFS-3860] HeartbeatManager#Monitor may wrongly hold the writelock of namesystem

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.0-alpha1
• Fix Version/s: 0.23.4, 2.0.2-alpha
• Hadoop Flags: Reviewed
• Assignee: Jing Zhao
• Reporter: Jing Zhao
• Created: 27/Aug/12 23:39
• Updated: 12/May/16 18:17
• Resolved: 28/Aug/12 17:03

Description

In HeartbeatManager#heartbeatCheck, if some dead datanode is found, the monitor thread will acquire the write lock of namesystem, and recheck the safemode. If it is in safemode, the monitor thread will return from the heartbeatCheck function without release the write lock. This may cause the monitor thread wrongly holding the write lock forever.

The attached test case tries to simulate this bad scenario.