GFS2: Fix up some sparse warnings

This patch cleans up various pieces of GFS2 to avoid sparse errors.
This doesn't fix them all, but it fixes several. The first error,
in function glock_hash_walk was a genuine bug where the rhashtable
could be started and not stopped.
Signed-off-by: Bob Peterson <rpeterso@redhat.com>

fs/gfs2/glock.c

@@ -1550,14 +1550,15 @@ static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
 
 	do {
 		gl = ERR_PTR(rhashtable_walk_start(&iter));
-		if (gl)
-			continue;
+		if (IS_ERR(gl))
+			goto walk_stop;
 
 		while ((gl = rhashtable_walk_next(&iter)) && !IS_ERR(gl))
-			if ((gl->gl_name.ln_sbd == sdp) &&
+			if (gl->gl_name.ln_sbd == sdp &&
 			    lockref_get_not_dead(&gl->gl_lockref))
 				examiner(gl);
 
+walk_stop:
 		rhashtable_walk_stop(&iter);
 	} while (cond_resched(), gl == ERR_PTR(-EAGAIN));
 
@@ -1940,6 +1941,7 @@ static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi)
 }
 
 static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(RCU)
 {
 	struct gfs2_glock_iter *gi = seq->private;
 	loff_t n = *pos;
@@ -1972,6 +1974,7 @@ static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
 }
 
 static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
+	__releases(RCU)
 {
 	struct gfs2_glock_iter *gi = seq->private;
 

fs/gfs2/lock_dlm.c

@@ -23,8 +23,6 @@
 #include "sys.h"
 #include "trace_gfs2.h"
 
-extern struct workqueue_struct *gfs2_control_wq;
-
 /**
  * gfs2_update_stats - Update time based stats
  * @mv: Pointer to mean/variance structure to update
@@ -1176,7 +1174,7 @@ static void gdlm_recovery_result(struct gfs2_sbd *sdp, unsigned int jid,
 	spin_unlock(&ls->ls_recover_spin);
 }
 
-const struct dlm_lockspace_ops gdlm_lockspace_ops = {
+static const struct dlm_lockspace_ops gdlm_lockspace_ops = {
 	.recover_prep = gdlm_recover_prep,
 	.recover_slot = gdlm_recover_slot,
 	.recover_done = gdlm_recover_done,

fs/gfs2/util.h

@@ -151,6 +151,7 @@ extern struct kmem_cache *gfs2_rgrpd_cachep;
 extern struct kmem_cache *gfs2_quotad_cachep;
 extern struct kmem_cache *gfs2_qadata_cachep;
 extern mempool_t *gfs2_page_pool;
+extern struct workqueue_struct *gfs2_control_wq;
 
 static inline unsigned int gfs2_tune_get_i(struct gfs2_tune *gt,
 					   unsigned int *p)

fs/gfs2/xattr.c

@@ -25,6 +25,7 @@
 #include "meta_io.h"
 #include "quota.h"
 #include "rgrp.h"
+#include "super.h"
 #include "trans.h"
 #include "util.h"