+/*
+ * Grow a b-tree so that it has more records.
+ *
+ * We might shift the tree depth in which case existing paths should
+ * be considered invalid.
+ *
+ * Tree depth after the grow is returned via *final_depth.
+ */
+static int ocfs2_grow_tree(struct inode *inode, handle_t *handle,
+ struct buffer_head *di_bh, int *final_depth,
+ struct buffer_head *last_eb_bh,
+ struct ocfs2_alloc_context *meta_ac)
+{
+ int ret, shift;
+ struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+ int depth = le16_to_cpu(di->id2.i_list.l_tree_depth);
+ struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+ struct buffer_head *bh = NULL;
+
+ BUG_ON(meta_ac == NULL);
+
+ shift = ocfs2_find_branch_target(osb, inode, di_bh, &bh);
+ if (shift < 0) {
+ ret = shift;
+ mlog_errno(ret);
+ goto out;
+ }
+
+ /* We traveled all the way to the bottom of the allocation tree
+ * and didn't find room for any more extents - we need to add
+ * another tree level */
+ if (shift) {
+ BUG_ON(bh);
+ mlog(0, "need to shift tree depth (current = %d)\n", depth);
+
+ /* ocfs2_shift_tree_depth will return us a buffer with
+ * the new extent block (so we can pass that to
+ * ocfs2_add_branch). */
+ ret = ocfs2_shift_tree_depth(osb, handle, inode, di_bh,
+ meta_ac, &bh);
+ if (ret < 0) {
+ mlog_errno(ret);
+ goto out;
+ }
+ depth++;
+ /* Special case: we have room now if we shifted from
+ * tree_depth 0 */
+ if (depth == 1)
+ goto out;
+ }
+
+ /* call ocfs2_add_branch to add the final part of the tree with
+ * the new data. */
+ mlog(0, "add branch. bh = %p\n", bh);
+ ret = ocfs2_add_branch(osb, handle, inode, di_bh, bh, last_eb_bh,
+ meta_ac);
+ if (ret < 0) {
+ mlog_errno(ret);
+ goto out;
+ }
+
+out:
+ if (final_depth)
+ *final_depth = depth;
+ brelse(bh);
+ return ret;
+}
+