bcachefs: Fix btree key cache shutdown

On emergency shutdown, we might still have dirty keys in the btree key
cache that need to be cleaned up properly.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_key_cache.c

@@ -490,6 +490,9 @@ void bch2_fs_btree_key_cache_exit(struct btree_key_cache *bc)
 	list_splice(&bc->dirty, &bc->clean);
 
 	list_for_each_entry_safe(ck, n, &bc->clean, list) {
+		bch2_journal_pin_drop(&c->journal, &ck->journal);
+		bch2_journal_preres_put(&c->journal, &ck->res);
+
 		kfree(ck->k);
 		kfree(ck);
 		bc->nr_keys--;

fs/bcachefs/journal_reclaim.c

@@ -263,6 +263,7 @@ static void bch2_journal_reclaim_fast(struct journal *j)
 	while (!fifo_empty(&j->pin) &&
 	       !atomic_read(&fifo_peek_front(&j->pin).count)) {
 		BUG_ON(!list_empty(&fifo_peek_front(&j->pin).list));
+		BUG_ON(!list_empty(&fifo_peek_front(&j->pin).flushed));
 		BUG_ON(!fifo_pop(&j->pin, temp));
 		popped = true;
 	}