btrfs-progs: check: Fix wrong root parameter of btrfs_next_leaf call

The first thing that check_chunks_and_extents does is to iterate all
the root items in the root tree and link them to either the "normal_list"
or "dropping_trees" list. If a leaf has to be crossed during this
operation btrfs_next_leaf is called to do that. However, currently it's
called with a wrong argument for its 'root' parameter. Since we are
iterating the root tree the passed root should be fs_info->tree_rot,
whereas right now we are passing the local variable 'root' which is
assigned to the fs_tree. As it stands, this bug is actually benign since
the passed root is only passed to reada_for_search, where it's used to
reference the fs_info. Nevertheless the code is wrong and at the very least
misleading, so fix it by passing the correct root.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Su Yue <suy.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>

check/main.c

@@ -8163,7 +8163,7 @@ again:
 		leaf = path.nodes[0];
 		slot = path.slots[0];
 		if (slot >= btrfs_header_nritems(path.nodes[0])) {
-			ret = btrfs_next_leaf(root, &path);
+			ret = btrfs_next_leaf(fs_info->tree_root, &path);
 			if (ret != 0)
 				break;
 			leaf = path.nodes[0];