[HDFS-1775] getContentSummary should hold the FSNamesystem readlock

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Duplicate
• Assignee: Dmytro Molkov
• Reporter: Dmytro Molkov
• Created: 22/Mar/11 18:29
• Updated: 12/Jul/13 18:34
• Resolved: 12/Jul/13 18:34

Description

Right now the getContentSummary call on the namenode only holds the FSDirectory lock, but not the FSNamesystem lock. What we are seeing because of that is:
1) getContentSummary takes the read lock on FSDirectory
2) the write operation comes and takes a write lock on FSNamesystem and waits for getContentSummary to finish to get a write lock on FSDirectory

As a result other read operations can't be executed. Since getContentSummary can take a while to execute on large directories, the performance would be improved if we hold a readlock while doing that.

Issue Links

• is duplicated by: HDFS-988 saveNamespace race can corrupt the edits log