gfs2: Save ip from gfs2_glock_nq_init

Before this patch, when a glock was locked by function gfs2_glock_nq_init,
it initialized the holder gh_ip (return address) as gfs2_glock_nq_init.
That made it extremely difficult to track down problems because many
functions call gfs2_glock_nq_init. This patch changes the function so
that it saves gh_ip from the caller of gfs2_glock_nq_init, which makes
it easy to backtrack which holder took the lock.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>

fs/gfs2/glock.c

@@ -911,7 +911,7 @@ static void gfs2_glock_poke(struct gfs2_glock *gl)
 	struct gfs2_holder gh;
 	int error;
 
-	gfs2_holder_init(gl, LM_ST_SHARED, flags, &gh);
+	__gfs2_holder_init(gl, LM_ST_SHARED, flags, &gh, _RET_IP_);
 	error = gfs2_glock_nq(&gh);
 	if (!error)
 		gfs2_glock_dq(&gh);
@@ -1208,12 +1208,12 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
  *
  */
 
-void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, u16 flags,
-		      struct gfs2_holder *gh)
+void __gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, u16 flags,
+			struct gfs2_holder *gh, unsigned long ip)
 {
 	INIT_LIST_HEAD(&gh->gh_list);
 	gh->gh_gl = gl;
-	gh->gh_ip = _RET_IP_;
+	gh->gh_ip = ip;
 	gh->gh_owner_pid = get_pid(task_pid(current));
 	gh->gh_state = state;
 	gh->gh_flags = flags;

fs/gfs2/glock.h

@@ -190,8 +190,15 @@ extern int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
 extern void gfs2_glock_hold(struct gfs2_glock *gl);
 extern void gfs2_glock_put(struct gfs2_glock *gl);
 extern void gfs2_glock_queue_put(struct gfs2_glock *gl);
-extern void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
-			     u16 flags, struct gfs2_holder *gh);
+
+extern void __gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
+			       u16 flags, struct gfs2_holder *gh,
+			       unsigned long ip);
+static inline void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
+				    u16 flags, struct gfs2_holder *gh) {
+	__gfs2_holder_init(gl, state, flags, gh, _RET_IP_);
+}
+
 extern void gfs2_holder_reinit(unsigned int state, u16 flags,
 			       struct gfs2_holder *gh);
 extern void gfs2_holder_uninit(struct gfs2_holder *gh);
@@ -241,7 +248,7 @@ static inline int gfs2_glock_nq_init(struct gfs2_glock *gl,
 {
 	int error;
 
-	gfs2_holder_init(gl, state, flags, gh);
+	__gfs2_holder_init(gl, state, flags, gh, _RET_IP_);
 
 	error = gfs2_glock_nq(gh);
 	if (error)