[HDFS-13962] Add null check for add-replica pool to avoid lock acquiring

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.1.1
• Fix Version/s: 3.2.0, 3.1.2, 3.3.0
• Target Version/s: 3.2.0, 3.1.2, 3.3.0
• Hadoop Flags: Reviewed
• Assignee: Surendra Singh Lilhore
• Reporter: Yiqun Lin
• Created: 05/Oct/18 08:28
• Updated: 09/Oct/18 02:58
• Resolved: 09/Oct/18 02:39

Description

This is a follow-up work for HDFS-13768. Mainly two places needed to update:

• Add null check for add-replica pool to avoid lock acquiring
• In ReplicaMap#addAndGet, it would be better to use FoldedTreeSet#addOrReplace instead of FoldedTreeSet#add for adding replica info. This is for the logic consistentency with add operation

Issue Links

• relates to: HDFS-13768 Adding replicas to volume map makes DataNode start slowly