bcachefs: Fix error in filesystem initialization

The rhashtable code doesn't like when we destroy an rhashtable that was
never initialized
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_key_cache.c

@@ -608,7 +608,8 @@ void bch2_fs_btree_key_cache_exit(struct btree_key_cache *bc)
 	}
 	mutex_unlock(&bc->lock);
 
-	rhashtable_destroy(&bc->table);
+	if (bc->table_init_done)
+		rhashtable_destroy(&bc->table);
 }
 
 void bch2_fs_btree_key_cache_init_early(struct btree_key_cache *c)
@@ -622,13 +623,19 @@ void bch2_fs_btree_key_cache_init_early(struct btree_key_cache *c)
 int bch2_fs_btree_key_cache_init(struct btree_key_cache *bc)
 {
 	struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
+	int ret;
 
 	bc->shrink.seeks		= 1;
 	bc->shrink.count_objects	= bch2_btree_key_cache_count;
 	bc->shrink.scan_objects		= bch2_btree_key_cache_scan;
 
-	return  register_shrinker(&bc->shrink, "%s/btree_key_cache", c->name) ?:
+	ret =   register_shrinker(&bc->shrink, "%s/btree_key_cache", c->name) ?:
 		rhashtable_init(&bc->table, &bch2_btree_key_cache_params);
+	if (ret)
+		return ret;
+
+	bc->table_init_done = true;
+	return 0;
 }
 
 void bch2_btree_key_cache_to_text(struct printbuf *out, struct btree_key_cache *c)

fs/bcachefs/btree_types.h

@@ -293,6 +293,7 @@ static inline struct btree_iter_level *iter_l(struct btree_iter *iter)
 struct btree_key_cache {
 	struct mutex		lock;
 	struct rhashtable	table;
+	bool			table_init_done;
 	struct list_head	freed;
 	struct list_head	clean;
 	struct list_head	dirty;