[GFS2] Make glock operations const

For all the usual reasons of enforcing correctness and potentially
reducing code size, this patch makes the glock operations const.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/glock.h b/fs/gfs2/glock.h
index fdf58db..12bdbfe 100644
--- a/fs/gfs2/glock.h
+++ b/fs/gfs2/glock.h
@@ -75,7 +75,7 @@
 }
 
 int gfs2_glock_get(struct gfs2_sbd *sdp,
-		   uint64_t number, struct gfs2_glock_operations *glops,
+		   uint64_t number, const struct gfs2_glock_operations *glops,
 		   int create, struct gfs2_glock **glp);
 void gfs2_glock_hold(struct gfs2_glock *gl);
 int gfs2_glock_put(struct gfs2_glock *gl);
@@ -97,7 +97,7 @@
 
 void gfs2_glock_dq_uninit(struct gfs2_holder *gh);
 int gfs2_glock_nq_num(struct gfs2_sbd *sdp,
-		      uint64_t number, struct gfs2_glock_operations *glops,
+		      uint64_t number, const struct gfs2_glock_operations *glops,
 		      unsigned int state, int flags, struct gfs2_holder *gh);
 
 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs);
@@ -105,7 +105,7 @@
 void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs);
 
 void gfs2_glock_prefetch_num(struct gfs2_sbd *sdp, uint64_t number,
-			     struct gfs2_glock_operations *glops,
+			     const struct gfs2_glock_operations *glops,
 			     unsigned int state, int flags);
 void gfs2_glock_inode_squish(struct inode *inode);