[HADOOP-2413] Is FSNamesystem.fsNamesystemObject unique?

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.15.1
• Fix Version/s: 0.21.0
• Hadoop Flags: Reviewed
• Assignee: Konstantin Shvachko
• Reporter: Tsz-wo Sze
• Created: 12/Dec/07 23:10
• Updated: 24/Aug/10 20:33
• Resolved: 01/Apr/09 18:45

Description

FSNamesystem is unique in almost all cases but it is not universally true. So we should either remove the static variable FSNamesystem.fsNamesystemObject or make it final (so that it cannot be overwritten).

When I am working on HADOOP-1298, I use the convenient static method FSNamesystem.getFSNamesystem() to get "the" FSNamesystem object. However, it keeps failing on TestCheckpoint. Why? It is because TestCheckpoint uses NameNode and SecondaryNameNode. Both of them are creating FSNamesystem. So FSNamesystem.fsNamesystemObject does not remain constant. The kind of bug is hard to be detected.

Issue Links

• is related to: HADOOP-5017 NameNode.namesystem should be private

Sub-Tasks

• Deprecate FSNamesystem.getFSNamesystem() and change fsNamesystemObject to private: Closed
• Remove static variable JspHelper.fsn: Closed
• FSEditLog should not use FSNamesystem.getFSNamesystem(): Closed
• UpgradeManagerNamenode and UpgradeObjectNamenode should not use FSNamesystem.getFSNamesystem(): Closed
• BackupStorage should not use FSNamesystem.getFSNamesystem(): Closed