From 281c1abdfa76e14ca3aee42a17ed9798b6cd934a Mon Sep 17 00:00:00 2001
From: "S.J.R. van Schaik" <stephan@whiteboxsystems.nl>
Date: Mon, 29 May 2017 14:41:47 +0200
Subject: [PATCH] mufs: add mufs_extend_tree() to extend the depth of a file
 tree

---
 source/fs/mufs/tree.c | 21 +++++++++++++++++++++
 source/fs/mufs/tree.h |  1 +
 2 files changed, 22 insertions(+)

diff --git a/source/fs/mufs/tree.c b/source/fs/mufs/tree.c
index 01ad819..5f7c697 100644
--- a/source/fs/mufs/tree.c
+++ b/source/fs/mufs/tree.c
@@ -95,3 +95,24 @@ void mufs_free_page(struct mufs *fs, struct mufs_tree *tree, uint32_t va)
 {
 	mufs_do_free_page(fs, tree->root, tree->depth, va);
 }
+
+int mufs_extend_tree(struct mufs *fs, struct mufs_tree *tree, uint8_t depth)
+{
+	uint32_t root;
+
+	for (; tree->depth < depth; ++tree->depth) {
+		if (mufs_alloc_block(fs, &root) < 0)
+			return -1;
+
+		if (!root)
+			continue;
+
+		if (flash_write(fs->dev, root << fs->dev->log2_block_size, &tree->root,
+			sizeof tree->root) == 0) {
+			mufs_free_block(fs, root);
+			return -1;
+		}
+	}
+
+	return 0;
+}
diff --git a/source/fs/mufs/tree.h b/source/fs/mufs/tree.h
index ac7f60f..45650a4 100644
--- a/source/fs/mufs/tree.h
+++ b/source/fs/mufs/tree.h
@@ -5,3 +5,4 @@ int mufs_lookup_page(struct mufs *fs, struct mufs_tree *tree, uint32_t *page,
 int mufs_alloc_page(struct mufs *fs, struct mufs_tree *tree, uint32_t *page,
 	uint32_t va);
 void mufs_free_page(struct mufs *fs, struct mufs_tree *tree, uint32_t va);
+int mufs_extend_tree(struct mufs *fs, struct mufs_tree *tree, uint8_t depth);