When opening a shared Microsoft Office file, you may see the error message “File in Use, file_name is locked for editing by user_name“, when in fact no other user is currently using the file.
We had users that would view files with the preview pane, it would create a lock on the file, and then when the explorer window was closed the lock would remain. The next time the file was accessed it would state that it was locked even though the user didn’t have it open. Below are some steps you can take to troubleshoot and resolve the issue. Note that changing some of these parameters can have a performance impact, so make these changes at your own risk. Oplocks let clients lock files and locally cache information while preventing another user from changing the file. This increases performance for many file operations.
1. Disable Oplocks on the VNX
Disabling oplocks can affect client performance. It will increase the number of metadata requests that are sent to the server because when you use SMB with oplocks, the client caches the data that is locked to speed up access to frequently accessed files. When oplocks are disabled, the client does not cache data and all reads are made directly to the NAS server.
Syntax for disabling oplocks and verifying the change:
[nasadmin@VNX1 ~]$ server_mount vdm_file_system -o nooplock test_file_system01_fs /test_file_system01 vdm_file_system : done [nasadmin@VNX1 ~]$ server_mount vdm_file_system | grep test_file_system01_fs test_file_system01_fs on /test_file_system01 uxfs,perm,rw,noprefetch,nonotify,accesspolicy=NATIVE,nooplock
2. Disable caching on the Windows client
The Windows client setting controls the cache lifetime. As stated earlier, if caching is disabled on the windows client then all reads are to the NAS server directly. In order to to disable caching on the windows client rather than disabling oplocks on the VNX Data Mover, the following three registry changes would need to be made:
– Directory cache, set DirectoryCacheLifetime to Zero.
– File Not Found cache, set FileNotFoundCacheLifetime to Zero.
– File information cache, set FileInfoCacheLifetime to Zero.
3. Apply a Microsoft hotfix
The Microsoft KB article http://support.microsoft.com/kb/942146 describes the problem and the fix in detail. It directly addresses the issue with files locking from the preview pane. It applies to all versions of Windows Vista and 7 as well as Windows Server 2008.