[DLM] canceling deadlocked lock

Add a function that can be used through libdlm by a system daemon to cancel
another process's deadlocked lock.  A completion ast with EDEADLK is returned
to the process waiting for the lock.

Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/include/linux/dlm_device.h b/include/linux/dlm_device.h
index f7b9b57..9642277 100644
--- a/include/linux/dlm_device.h
+++ b/include/linux/dlm_device.h
@@ -92,6 +92,7 @@
 #define DLM_USER_CREATE_LOCKSPACE  4
 #define DLM_USER_REMOVE_LOCKSPACE  5
 #define DLM_USER_PURGE        6
+#define DLM_USER_DEADLOCK     7
 
 /* Arbitrary length restriction */
 #define MAX_LS_NAME_LEN 64