bcachefs: Add new assertions for shutdown path

We've been seeing assertions pop that indicate the btree node cache or
key cache have dirty items when we just did a clean shutdown.

Add some more assertions so we can catch this when we're dirtying items.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_key_cache.c

@@ -780,6 +780,7 @@ bool bch2_btree_insert_key_cached(struct btree_trans *trans,
 	ck->valid = true;
 
 	if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
+		EBUG_ON(test_bit(BCH_FS_CLEAN_SHUTDOWN, &c->flags));
 		set_bit(BKEY_CACHED_DIRTY, &ck->flags);
 		atomic_long_inc(&c->btree_key_cache.nr_dirty);
 

fs/bcachefs/btree_update_leaf.c

@@ -272,8 +272,10 @@ inline void bch2_btree_insert_key_leaf(struct btree_trans *trans,
 
 	bch2_btree_add_journal_pin(c, b, journal_seq);
 
-	if (unlikely(!btree_node_dirty(b)))
+	if (unlikely(!btree_node_dirty(b))) {
+		EBUG_ON(test_bit(BCH_FS_CLEAN_SHUTDOWN, &c->flags));
 		set_btree_node_dirty_acct(c, b);
+	}
 
 	live_u64s_added = (int) b->nr.live_u64s - old_live_u64s;
 	u64s_added = (int) bset_u64s(t) - old_u64s;