bcachefs: Btree key cache coherency

 - Updates to non key cache iterators will now be transparently
   redirected to the key cache for cached btrees.

 - Except when creating new keys: then the update goes to underlying
   btree

For for iterating over a cached btree to work, we need to ensure that if
a key exists in the key cache, it also exists in the btree - otherwise
the iterator code will skip past it and not check the key cache.

Otherwise, for consistency, all updates should go to the same place -
the key cache.

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

1 files changed, 2 insertions, 8 deletions

diff --git a/fs/bcachefs/btree_key_cache.h b/fs/bcachefs/btree_key_cache.h
index b3d241b13453..670746e72dab 100644
--- a/fs/bcachefs/btree_key_cache.h
+++ b/fs/bcachefs/btree_key_cache.h
@@ -32,14 +32,8 @@ bool bch2_btree_insert_key_cached(struct btree_trans *,
 			struct btree_path *, struct bkey_i *);
 int bch2_btree_key_cache_flush(struct btree_trans *,
 			       enum btree_id, struct bpos);
-#ifdef CONFIG_BCACHEFS_DEBUG
-void bch2_btree_key_cache_verify_clean(struct btree_trans *,
-				enum btree_id, struct bpos);
-#else
-static inline void
-bch2_btree_key_cache_verify_clean(struct btree_trans *trans,
-				enum btree_id id, struct bpos pos) {}
-#endif
+void bch2_btree_key_cache_drop(struct btree_trans *,
+			       struct btree_path *);
 
 void bch2_fs_btree_key_cache_exit(struct btree_key_cache *);
 void bch2_fs_btree_key_cache_init_early(struct btree_key_cache *);