From f262c7bbc72796ae36b7e40dc38ab7167d138d5b Mon Sep 17 00:00:00 2001
From: Luke Shumaker <lukeshu@lukeshu.com>
Date: Sat, 15 Apr 2023 09:00:33 -0600
Subject: btrfsutil: RebuiltForrest: Add a lax-ancestor mode

---
 lib/btrfs/btrfstree/path.go | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'lib/btrfs/btrfstree')

diff --git a/lib/btrfs/btrfstree/path.go b/lib/btrfs/btrfstree/path.go
index acc0e73..327a39b 100644
--- a/lib/btrfs/btrfstree/path.go
+++ b/lib/btrfs/btrfstree/path.go
@@ -12,6 +12,7 @@ import (
 	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsprim"
 	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsvol"
 	"git.lukeshu.com/btrfs-progs-ng/lib/containers"
+	"git.lukeshu.com/btrfs-progs-ng/lib/slices"
 )
 
 // Path is a path from the superblock or a ROOT_ITEM to a node or
@@ -137,6 +138,7 @@ func checkOwner(
 	ctx context.Context, forrest Forrest, treeID btrfsprim.ObjID,
 	ownerToCheck btrfsprim.ObjID, genToCheck btrfsprim.Generation,
 ) error {
+	var stack []btrfsprim.ObjID
 	for {
 		if ownerToCheck == treeID {
 			return nil
@@ -154,6 +156,12 @@ func checkOwner(
 				ownerToCheck, genToCheck, err)
 		}
 
+		stack = append(stack, treeID)
+		if slices.Contains(parentID, stack) {
+			// Don't get stuck in an infinite loop if there's a cycle.
+			parentID = 0
+		}
+
 		if parentID == 0 && parentGen == 0 {
 			return fmt.Errorf("owner=%v is not acceptable in this tree",
 				ownerToCheck)
-- 
cgit v1.2.3-2-g168b