GFS2: Use generic list_lru for quota

By using the generic list_lru code, we can now separate the
per sb quota list locking from the lru locking. The lru
lock is made into the inner-most lock.

As a result of this new lock order, we may occasionally see
items on the per-sb quota list which are "dead" so that the
two places where we traverse that list are updated to take
account of that.

As a result of this patch, the gfs2 quota shrinker is now
NUMA zone aware, and we are also laying the foundations for
further improvments in due course.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Abhijith Das <adas@redhat.com>
Tested-by: Abhijith Das <adas@redhat.com>
Cc: Dave Chinner <dchinner@redhat.com>

fs/gfs2/quota.h

@@ -10,9 +10,10 @@
 #ifndef __QUOTA_DOT_H__
 #define __QUOTA_DOT_H__
 
+#include <linux/list_lru.h>
+
 struct gfs2_inode;
 struct gfs2_sbd;
-struct shrink_control;
 
 #define NO_UID_QUOTA_CHANGE INVALID_UID
 #define NO_GID_QUOTA_CHANGE INVALID_GID
@@ -53,10 +54,8 @@ static inline int gfs2_quota_lock_check(struct gfs2_inode *ip)
 	return ret;
 }
 
-extern unsigned long gfs2_qd_shrink_count(struct shrinker *shrink,
-					  struct shrink_control *sc);
-extern unsigned long gfs2_qd_shrink_scan(struct shrinker *shrink,
-					 struct shrink_control *sc);
 extern const struct quotactl_ops gfs2_quotactl_ops;
+extern struct shrinker gfs2_qd_shrinker;
+extern struct list_lru gfs2_qd_lru;
 
 #endif /* __QUOTA_DOT_H__ */