[HDFS-5195] Prevent passing null pointer to mlock and munlock.

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: HDFS-4949
• Fix Version/s: HDFS-4949
• Component/s: datanode
• Target Version/s: HDFS-4949
• Hadoop Flags: Reviewed
• Assignee: Chris Nauroth
• Reporter: Chris Nauroth
• Created: 12/Sep/13 22:36
• Updated: 13/Sep/13 20:48
• Resolved: 13/Sep/13 20:48

Description

According to JNI documentation, it is optional for the JVM to support the GetDirectBufferAddress function. If unsupported, then the function will return null. This is probably a very rare thing, but let's be defensive by checking the return value for null and throwing an exception instead of passing null down to mlock and munlock.

Issue Links

• relates to: HDFS-4949 Centralized cache management in HDFS