[HDFS-1648] Federation: Only DataStorage must be locked using in_use.lock and no locks must be associated with BlockPoolStorage

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: Federation Branch
• Fix Version/s: Federation Branch
• Component/s: datanode
• Hadoop Flags: Reviewed
• Assignee: Tanping Wang
• Reporter: Tanping Wang
• Created: 24/Feb/11 22:42
• Updated: 28/Feb/11 21:33
• Resolved: 25/Feb/11 22:45

Description

StorageDirectory locks in_use.lock file, when analyzeStorage() method is called during
initialization.

Since BlockPoolStorage uses this method, an in_use.lock file is created and locked under BlockPool directory
<StorageDirectory>/current/bpid/. This lock is not released when datanode shutsdown. Restarting datanode without
formatting it results in datanode failure to acquire in_use.lock and hence failure to restart.

in_use.lock file that currently exists in <StorageDirectory> (at the datanode level) is sufficient to prevent two
instances of datanodes running on the same node. There is no need for such a lock in block pool directories.

Change is needed so that BlockPoolStorage can disable locking when it creates it's StorageDirectory.