From: Kent Overstreet <kent.overstreet@linux.dev>
Date: Fri, 13 Jun 2025 19:17:37 +0000 (-0400)
Subject: bcachefs: better __bch2_snapshot_is_ancestor() assert
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=f2ed0892732d470abde7a1af360bd670dc8a68c6;p=linux-block.git

bcachefs: better __bch2_snapshot_is_ancestor() assert

Previously, we weren't checking the result of the skiplist walk, just
the is_ancestor bitmap.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
---

diff --git a/fs/bcachefs/snapshot.c b/fs/bcachefs/snapshot.c
index 23a332d76b32..38aeaa128d27 100644
--- a/fs/bcachefs/snapshot.c
+++ b/fs/bcachefs/snapshot.c
@@ -135,7 +135,9 @@ static bool test_ancestor_bitmap(struct snapshot_table *t, u32 id, u32 ancestor)
 
 bool __bch2_snapshot_is_ancestor(struct bch_fs *c, u32 id, u32 ancestor)
 {
-	bool ret;
+#ifdef CONFIG_BCACHEFS_DEBUG
+	u32 orig_id = id;
+#endif
 
 	guard(rcu)();
 	struct snapshot_table *t = rcu_dereference(c->snapshots);
@@ -147,11 +149,11 @@ bool __bch2_snapshot_is_ancestor(struct bch_fs *c, u32 id, u32 ancestor)
 		while (id && id < ancestor - IS_ANCESTOR_BITMAP)
 			id = get_ancestor_below(t, id, ancestor);
 
-	ret = id && id < ancestor
+	bool ret = id && id < ancestor
 		? test_ancestor_bitmap(t, id, ancestor)
 		: id == ancestor;
 
-	EBUG_ON(ret != __bch2_snapshot_is_ancestor_early(t, id, ancestor));
+	EBUG_ON(ret != __bch2_snapshot_is_ancestor_early(t, orig_id, ancestor));
 	return ret;
 }