btrfsutil: RebuiltTree: TreeWalk: Touch up

 - Go ahead and have .NodeExpectations fail closed.  It shouldn't make a
   difference at this point, but being stricter here is better.

 - Add a sanity check that the walker hasn't disagreed from the nodeIndex.
   At the leafs, the sanity check on items.Load should detect this, but
   let's detect it earlier to make things easier to debug.

1 files changed, 5 insertions, 1 deletions

diff --git a/lib/btrfsutil/rebuilt_tree.go b/lib/btrfsutil/rebuilt_tree.go
index 70be4c8..8d5921b 100644
--- a/lib/btrfsutil/rebuilt_tree.go
+++ b/lib/btrfsutil/rebuilt_tree.go
@@ -660,7 +660,7 @@ func (walker *rebuiltWalker) walk(ctx context.Context, path btrfstree.Path) {
 	}
 
 	// 001
-	nodeAddr, nodeExp, ok := path.NodeExpectations(ctx, true)
+	nodeAddr, nodeExp, ok := path.NodeExpectations(ctx, false)
 	if !ok {
 		panic(fmt.Errorf("should not happen: btrfsutil.rebuiltWalker.walk called with non-node path: %v",
 			path))
@@ -686,6 +686,10 @@ func (walker *rebuiltWalker) walk(ctx context.Context, path btrfstree.Path) {
 		}
 		return
 	}
+	if !maps.HaveAnyKeysInCommon(walker.tree.Roots, walker.nodeIndex.nodeToRoots[nodeAddr]) {
+		panic(fmt.Errorf("should not happen: node@%v is not in the tree, but did not error: path=%#v exp=%#v",
+			nodeAddr, path, nodeExp))
+	}
 	if walker.visited.Has(nodeAddr) {
 		return
 	}