[GIRAPH-1076] Race condition in FileTxnSnapLog

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.2.0
• Assignee: Sergey Edunov
• Reporter: Sergey Edunov
• Created: 21/Jun/16 16:40
• Updated: 14/Oct/16 00:45
• Resolved: 21/Jun/16 17:18

Description

org.apache.zookeeper.server.persistence.FileTxnSnapLog has a potential for race condition:

if (!this.dataDir.exists()) {
if (!this.dataDir.mkdirs())

{ throw new IOException("Unable to create data directory " + this.dataDir); }

}

If two threads try to create FileTxnSnapLog simultaneously it can trigger IOException.
We saw this happening in Giraph where FileTxnSnapLog is being created by PurgeTask created by DatadirCleanupManager and by InProcessZooKeeperRunner#runFromConfig