[pnfs] pnfs-gfs2: DLM API changes in 2.6.26

[J. Bruce Fields]

On Thu, Jun 12, 2008 at 09:02:37AM -0500, David Teigland wrote:
> On Thu, Jun 12, 2008 at 08:47:20AM -0400, david m. richter wrote:
> > > 	hello,
> > > 
> > > 	benny and i found that we couldn't get one of the GFS2 daemons 
> > > (gfs_controld) to start after the rebase to 2.6.26-rc4.  attached is a 
> > > patch against the cluster-2.03.04 package [1] that will allow you to 
> > > rebuild the userland parts.  only minimally tested, but the cluster does 
> > > come up now and seems okay so far.
> > > 
> > > 	longer story: after initially being unable to rebuild userland, i 
> > > noticed some changes that came in 2.6.26: linux/lock_dlm_plock.h became 
> > > linux/dlm_plock.h, GDLM*/gdlm* functions and data structures lost the 
> > > leading "g", and an entry in /proc/misc was renamed.
> > > 
> > > 	gitk shows that kernel commit 
> > > 2402211a8389282fd2942fad4511f02c0eeeffc5 moved some posix lock code out so 
> > > gfs2 and ocfs2 could share it -- ah-ha. i didn't see a corresponding 
> > > update in the cluster userland git repo [2] yet, so i'll run with my patch 
> > > and see how things go.
> 
> Yes, our userland releases (and git tree) are meant to match the latest
> released kernel, so the patch to make this work is pending the real 2.6.26.
> See https://www.redhat.com/archives/cluster-devel/2008-April/msg00143.html

So what exactly are the rules expected to be for compatibility between
gfs2 kernel and userland?  Surely users can't be required to upgrade the
two in lock-step?

--b.