[HDFS-15718] Optimize hdfs token op writeLock

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Later
• Component/s: hdfs, namenode
• Labels: pull-request-available
• Assignee: Ahmed Hussein
• Reporter: Ahmed Hussein
• Created: 08/Dec/20 15:34
• Updated: 11/Dec/20 21:34
• Resolved: 11/Dec/20 21:34

Description

Daryn Sharp noticed that token operations are acquiring the fsn write lock. Like lease renewal and token expiration, the read lock is sufficient because the namesystem is not mutated.

Issue Links

• is related to: HDFS-15217 Add more information to longest write/read lock held log
• is required by: HADOOP-17416 Reduce synchronization in the token secret manager
• is required by: HADOOP-17417 Reduce UGI overhead in token ops
• links to: GitHub Pull Request #2531