mufs: fix mufs_free_page() and mufs_unmap_page() to properly update the root pointer

source/fs/mufs/tree.c

@@ -80,7 +80,7 @@ int mufs_alloc_page(struct mufs_tree *tree, uint32_t *page,
 	return mufs_do_lookup(fs, page, tree->root, tree->depth, va, 0, 1);
 }
 
-static int mufs_do_free_page(struct mufs *fs, uint32_t base,
+static int mufs_do_free_page(struct mufs *fs, uint32_t *base,
 	uint8_t depth, uint32_t va, int free_page)
 {
 	struct flash_dev *dev = fs->dev;
@@ -88,49 +88,54 @@ static int mufs_do_free_page(struct mufs *fs, uint32_t base,
 	uint32_t *table = (uint32_t *)data;
 	size_t index;
 
-	if (!base)
+	if (!base || *base == 0)
 		return -1;
 
 	if (!depth) {
-		if (free_page)
+		if (free_page) {
-			mufs_free_block(fs, base);
+			mufs_free_block(fs, *base);
+			*base = 0;
+		}
 
 		return 0;
 	}
 
-	if (flash_read(fs->dev, base << dev->log2_block_size, data,
+	if (flash_read(fs->dev, *base << dev->log2_block_size, data,
 		sizeof data) == 0)
 		return -1;
 
 	index = va & ((1 << (fs->log2_nentries * (depth - 1))) - 1);
 
-	if (mufs_do_free_page(fs, table[index], depth - 1, va, free_page) < 0)
+	if (mufs_do_free_page(fs, table + index, depth - 1, va, free_page) < 0)
 		return -1;
 
-	table[index] = 0;
-
 	for (index = 0; index < (UINT32_C(1) << fs->log2_nentries); ++index) {
 		if (!table[index])
 			continue;
 
-		if (flash_write(dev, base << dev->log2_block_size, data,
+		if (flash_write(dev, *base << dev->log2_block_size, data,
 			sizeof data) == 0)
 			return -1;
 
 		return 0;
 	}
 
-	return mufs_free_block(fs, base);
+	if (mufs_free_block(fs, *base) < 0)
+		return -1;
+
+	*base = 0;
+
+	return 0;
 }
 
 void mufs_unmap_page(struct mufs_tree *tree, uint32_t va)
 {
-	mufs_do_free_page(tree->fs, tree->root, tree->depth, va, 0);
+	mufs_do_free_page(tree->fs, &tree->root, tree->depth, va, 0);
 }
 
 void mufs_free_page(struct mufs_tree *tree, uint32_t va)
 {
-	mufs_do_free_page(tree->fs, tree->root, tree->depth, va, 1);
+	mufs_do_free_page(tree->fs, &tree->root, tree->depth, va, 1);
 }
 
 int mufs_extend_tree(struct mufs_tree *tree, uint8_t depth)