GFS2: only use lvb on glocks that need it

Save the effort of allocating, reading and writing
the lvb for most glocks that do not use it.

Signed-off-by: David Teigland <teigland@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index a35ef5c..bd577fc 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -216,6 +216,7 @@
 	const int go_type;
 	const unsigned long go_flags;
 #define GLOF_ASPACE 1
+#define GLOF_LVB    2
 };
 
 enum {
@@ -321,7 +322,7 @@
 	ktime_t gl_dstamp;
 	struct gfs2_lkstats gl_stats;
 	struct dlm_lksb gl_lksb;
-	char gl_lvb[32];
+	char *gl_lvb;
 	unsigned long gl_tchange;
 	void *gl_object;