bcachefs: Fix bch2_btree_node_iter_prev_filter()

bch2_btree_node_iter_prev_filter() tried to be smart about iterating
backwards when skipping over whiteouts/discards - but unfortunately,
doing so can leave the node iterator in an inconsistent state; the sane
solution is to just always iterate backwards one key at a time.

But we compact btree nodes when more than a quarter of the keys are
whiteouts/discards, so the optimization wasn't buying us that much
anyways.

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

1 files changed, 2 insertions, 6 deletions

diff --git a/fs/bcachefs/bset.h b/fs/bcachefs/bset.h
index da3e41cc9757..209d2ed5db3a 100644
--- a/fs/bcachefs/bset.h
+++ b/fs/bcachefs/bset.h
@@ -543,16 +543,12 @@ bch2_btree_node_iter_next_all(struct btree_node_iter *iter, struct btree *b)
 	return ret;
 }
 
+struct bkey_packed *bch2_btree_node_iter_prev_all(struct btree_node_iter *,
+						  struct btree *);
 struct bkey_packed *bch2_btree_node_iter_prev_filter(struct btree_node_iter *,
 						     struct btree *, unsigned);
 
 static inline struct bkey_packed *
-bch2_btree_node_iter_prev_all(struct btree_node_iter *iter, struct btree *b)
-{
-	return bch2_btree_node_iter_prev_filter(iter, b, 0);
-}
-
-static inline struct bkey_packed *
 bch2_btree_node_iter_prev(struct btree_node_iter *iter, struct btree *b)
 {
 	return bch2_btree_node_iter_prev_filter(iter, b, KEY_TYPE_discard + 1);