mufs: add find_dirent_size() to determine how many bytes are used within a directory bin

source/fs/mufs/dir.c

@@ -182,6 +182,39 @@ void mufs_closedir(struct mufs_dir *dir)
 	free(dir);
 }
 
+size_t find_dirent_size(struct mufs *fs, struct mufs_tree *tree,
+	uint32_t va)
+{
+	struct flash_dev *dev = fs->dev;
+	size_t block_size = 1 << dev->log2_block_size;
+	char data[block_size];
+	struct mufs_dentry *entry;
+	uint32_t offset, len;
+
+	va = align(va, dev->log2_block_size);
+
+	if (mufs_tree_read(tree, data, va, 1 << dev->log2_block_size) == 0)
+		return 0;
+
+	for (offset = 0; offset < block_size; offset += len) {
+		entry = (struct mufs_dentry *)(data + offset);
+		len = sizeof *entry;
+
+		if (block_size - offset < len)
+			break;
+
+		if (!entry->type)
+			break;
+
+		len += entry->path_len;
+
+		if (block_size - offset < len)
+			break;
+	}
+
+	return offset;
+}
+
 size_t read_dirent(struct mufs *fs, struct mufs_tree *tree,
 	struct mufs_dirent *dirent, uint32_t va)
 {

source/fs/mufs/dir.h

@@ -20,6 +20,8 @@ struct mufs_dentry {
 
 struct mufs_tree *resolve_path(struct mufs *fs, const char *path,
 	struct mufs_stat *stat);
+size_t find_dirent_size(struct mufs *fs, struct mufs_tree *tree,
+	uint32_t va);
 size_t read_dirent(struct mufs *fs, struct mufs_tree *tree,
 	struct mufs_dirent *dirent, uint32_t va);
 size_t write_dirent(struct mufs_tree *tree,

source/fs/mufs/path.c

@@ -53,6 +53,8 @@ int mufs_mkpath(struct mufs *fs, const char *path, unsigned type)
 	dirent.tree.root = 0;
 	dirent.tree.depth = 0;
 
+	tree->file_size = find_dirent_size(fs, tree, tree->file_size);
+
 	if (!is_aligned(tree->file_size, fs->dev->log2_block_size) &&
 		write_dirent(tree, tree->file_size, &dirent) > 0)
 		return 0;