Byte-range locking fails in database applications

  • 7005097
  • 04-Jan-2010
  • 27-Apr-2012

Environment

Novell Client for Windows
Novell Client for Windows Vista/2008
Novell Client for Windows XP/2003
Novell NetWare 6.5 SP8
Novell Open Enterprise Server 2 SP2
Novell Storage Services (NSS) volumes

Situation

Applications performing byte range locking sometimes behave as though range is already locked.
Database applications succeed from one workstation, but cannot be accessed by second workstation until first workstation closes application.
Microsoft Access error message "Could not update; currently locked".

Although there are also situations where an application may legitimately have specific ranges of a data file locked to prevent other users from concurrently modifying sections of the file, instances are being observed where users of an application are being denied access to a byte range even when the byte range should be unlocked and available.

Resolution

This issue is resolved in the Novell Client 2 SP1 for Windows (IR1) or later. The issue was resolved by changing the Novell Client NCP lock releasing behavior in order to avoid the issue that was being observed at the NCP server.
 
Download the current update from https://download.novell.com/patch/finder/.

Additional Information

Analysis thus far as shown that although an unlock NCP for the affected byte range has been issued and successfully acknowledged by the NCP server, subsequent requests by the second workstation are denied with an NCP status indicating that the affected byte range is still locked.  Furthermore, once the original workstation finally closes its open NCP file handle to the affected file, then the affected ranges which should have already been unlocked finally become available for use by other NCP clients.