super: fix for destroy lrus

This patch adds the missing call to list_lru_destroy (spotted by Li Zhong)
and moves the deletion to after the shrinker is unregistered, as correctly
spotted by Dave

Signed-off-by: Glauber Costa <glommer@openvz.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/super.c

@@ -323,6 +323,9 @@ void deactivate_locked_super(struct super_block *s)
 
 		/* caches are now gone, we can safely kill the shrinker now */
 		unregister_shrinker(&s->s_shrink);
+		list_lru_destroy(&s->s_dentry_lru);
+		list_lru_destroy(&s->s_inode_lru);
+
 		put_filesystem(fs);
 		put_super(s);
 	} else {

fs/xfs/xfs_buf.c

@@ -1592,8 +1592,8 @@ xfs_free_buftarg(
 	struct xfs_mount	*mp,
 	struct xfs_buftarg	*btp)
 {
-	list_lru_destroy(&btp->bt_lru);
 	unregister_shrinker(&btp->bt_shrinker);
+	list_lru_destroy(&btp->bt_lru);
 
 	if (mp->m_flags & XFS_MOUNT_BARRIER)
 		xfs_blkdev_issue_flush(btp);

fs/xfs/xfs_qm.c

@@ -940,8 +940,8 @@ xfs_qm_destroy_quotainfo(
 	qi = mp->m_quotainfo;
 	ASSERT(qi != NULL);
 
-	list_lru_destroy(&qi->qi_lru);
 	unregister_shrinker(&qi->qi_shrinker);
+	list_lru_destroy(&qi->qi_lru);
 
 	if (qi->qi_uquotaip) {
 		IRELE(qi->qi_uquotaip);