dlm: check for undefined release_option values

Checking on all undefined release_option values to return -EINVAL in
case a user is providing them to dlm_release_lockspace().

Signed-off-by: Alexander Aring <[e-mail]>
Signed-off-by: David Teigland <[e-mail]>

fs/dlm/lockspace.c

···
 	struct dlm_ls *ls;
 	int error;
 
+	if (release_option > __DLM_RELEASE_MAX)
+		return -EINVAL;
+
 	ls = dlm_find_lockspace_local(lockspace);
 	if (!ls)
 		return -EINVAL;

include/linux/dlm.h

···
 #define DLM_RELEASE_NORMAL		2
 #define DLM_RELEASE_NO_EVENT		3
 #define DLM_RELEASE_RECOVER		4
+#define __DLM_RELEASE_MAX		DLM_RELEASE_RECOVER
 
 /*
  * dlm_release_lockspace