NFS Version 4 lock interfaces

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          Been testing some NFS Version 4 exports from my RHEL 4 server

mounted by  various FC13 & Scientific Linux clients.

  Have found that applications such as Firefox reported they couldn't obtain


  Closer investigation has shown  that the fcntl(2) system call is failing  with error no. ENOLOCK. By contrast the flock(2)  lock interface is working. 


 I found a bug report relating to RHEL5 that indicated this might be a kernel issue.

Has anynone been able to get this working under RHEL4?


 The kernel I am currently running is 2.6.18-164


Thanks in advance for any experiences related,



At several of my customers, we dropped back to NFSv3 for RHEL4.  We only use NFS4 on RHEL5+.


The implementation in early 2.6 kernels had various issues, so locking issues are not a bit surprising.  Locking, given the shift to a stateful approach in NFS4, is radically changed from the more stateless aspect of NFSv3.


Just a consideration, especially as RHEL4 will be EoL (except for ELS) in 2012 March.

The Kernel I mention above is in fact  the RHEL5 kernel mentioned

in an NFS locking bug report -  my RHEL4 kernel is 2.6.9-89.0.26

Thanks for sharing your experiences Bryan. I have mnaged to set up

a RHEL5 test server and NFS locking works  there over

V4 mounts. 

 One other difference to RHEL4 was that the virtual root must

be exported 'rw' for sub-dirs to be writeable.