[DLM] dlm_device interface changes [3/6]

Change the user/kernel device interface used by libdlm:
- Add ability for userspace to check the version of the interface.  libdlm
  can now adapt to different versions of the kernel interface.
- Increase the size of the flags passed in a lock request so all possible
  flags can be used from userspace.
- Add an opaque "xid" value for each lock.  This "transaction id" will be
  used later to associate locks with each other during deadlock detection.
- Add a "timeout" value for each lock.  This is used along with the
  DLM_LKF_TIMEOUT flag.

Also, remove a fragment of unused code in device_read().

This patch requires updating libdlm which is backward compatible with
older kernels.

Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

fs/dlm/dlm_internal.h

@@ -151,6 +151,7 @@ struct dlm_args {
 	void			*bastaddr;
 	int			mode;
 	struct dlm_lksb		*lksb;
+	unsigned long		timeout;
 };
 
 
@@ -528,6 +529,7 @@ struct dlm_user_args {
 	void __user		*castaddr;
 	void __user		*bastparam;
 	void __user		*bastaddr;
+	uint64_t		xid;
 };
 
 #define DLM_PROC_FLAGS_CLOSING 1