btrfsutil: RebuiltForrest: Add a lax-ancestor mode

1 files changed, 8 insertions, 0 deletions

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)