[VFS-487] File creation events missed when deleted then re-created within poll delay

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0
• Fix Version/s: 2.1
• Assignee: Bernd Eckenfels
• Reporter: Sam Haldane
• Created: 09/Aug/13 03:49
• Updated: 19/May/16 18:25
• Resolved: 30/Nov/14 09:49

Description

To reproduce:

• create a file monitor and add a directory with at least one child file
• set delay to 5 seconds and start the monitor
• delete a child file, wait for monitor to detect deletion
• re-create the child file within 5 seconds
• creation event is not detected

This is mainly due to this block being at the start of the main loop instead of the end:

            while (!this.deleteStack.empty())
            {
                this.removeFile(this.deleteStack.pop());
            }

When this is executed the file is in the stack from the previous poll and the file has already been re-created. removeFile calls FileMonitorAgent#resetChildrenList which updates the children list for that agent (which will contain the newly created file), but doesn't update the monitor map. The subsequent call to FileMonitorAgent#check in the main loop then doesn't detect the new file.

Moving the above block to the end of the main loop would prevent most occurrences of this issue, but the implementation is still racy.

Issue Links

• relates to: ACCUMULO-1507 Dynamic Classloader still can't keep proper track of jars