ocfs2: Determine an extent tree's max_leaf_clusters in an et_op.

Provide an optional extent_tree_operation to specify the
max_leaf_clusters of an ocfs2_extent_tree.  If not provided, the value
is 0 (unlimited).
Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

fs/ocfs2/alloc.c

@@ -76,6 +76,8 @@ struct ocfs2_extent_tree_operations {
 	/* These are internal to ocfs2_extent_tree and don't have
 	 * accessor functions */
 	void (*eo_fill_root_el)(struct ocfs2_extent_tree *et);
+	void (*eo_fill_max_leaf_clusters)(struct inode *inode,
+					  struct ocfs2_extent_tree *et);
 };
 
 struct ocfs2_extent_tree {
@@ -205,6 +207,14 @@ static void ocfs2_xattr_tree_fill_root_el(struct ocfs2_extent_tree *et)
 	et->et_root_el = &xb->xb_attrs.xb_root.xt_list;
 }
 
+static void ocfs2_xattr_tree_fill_max_leaf_clusters(struct inode *inode,
+						    struct ocfs2_extent_tree *et)
+{
+	et->et_max_leaf_clusters =
+		ocfs2_clusters_for_bytes(inode->i_sb,
+					 OCFS2_MAX_XATTR_TREE_LEAF_SIZE);
+}
+
 static void ocfs2_xattr_tree_set_last_eb_blk(struct ocfs2_extent_tree *et,
 					     u64 blkno)
 {
@@ -243,6 +253,7 @@ static struct ocfs2_extent_tree_operations ocfs2_xattr_tree_et_ops = {
 	.eo_update_clusters	= ocfs2_xattr_tree_update_clusters,
 	.eo_sanity_check	= ocfs2_xattr_tree_sanity_check,
 	.eo_fill_root_el	= ocfs2_xattr_tree_fill_root_el,
+	.eo_fill_max_leaf_clusters = ocfs2_xattr_tree_fill_max_leaf_clusters,
 };
 
 static void ocfs2_get_extent_tree(struct ocfs2_extent_tree *et,
@@ -254,7 +265,6 @@ static void ocfs2_get_extent_tree(struct ocfs2_extent_tree *et,
 	et->et_type = et_type;
 	get_bh(bh);
 	et->et_root_bh = bh;
-	et->et_max_leaf_clusters = 0;
 	if (!obj)
 		obj = (void *)bh->b_data;
 	et->et_object = obj;
@@ -265,11 +275,13 @@ static void ocfs2_get_extent_tree(struct ocfs2_extent_tree *et,
 		et->et_ops = &ocfs2_xattr_et_ops;
 	} else if (et_type == OCFS2_XATTR_TREE_EXTENT) {
 		et->et_ops = &ocfs2_xattr_tree_et_ops;
-		et->et_max_leaf_clusters = ocfs2_clusters_for_bytes(inode->i_sb,
-						OCFS2_MAX_XATTR_TREE_LEAF_SIZE);
 	}
 
 	et->et_ops->eo_fill_root_el(et);
+	if (!et->et_ops->eo_fill_max_leaf_clusters)
+		et->et_max_leaf_clusters = 0;
+	else
+		et->et_ops->eo_fill_max_leaf_clusters(inode, et);
 }
 
 static void ocfs2_put_extent_tree(struct ocfs2_extent_tree *et)