bcachefs: Fix fsck warning about btree_trans not passed to fsck error

If a btree_trans is in use it's supposed to be passed to fsck_err so
that it can be unlocked if we're waiting on userspace input; but the
btree IO paths do call fsck errors where a btree_trans exists on the
stack but it's not passed through.

But it's ok, because it's unlocked while doing IO.

Fixes: a850bde6 ("bcachefs: fsck_err() may now take a btree_trans")
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_iter.c

@@ -3282,7 +3282,8 @@ bool bch2_current_has_btree_trans(struct bch_fs *c)
 	struct btree_trans *trans;
 	bool ret = false;
 	list_for_each_entry(trans, &c->btree_trans_list, list)
-		if (trans->locking_wait.task == current) {
+		if (trans->locking_wait.task == current &&
+		    trans->locked) {
 			ret = true;
 			break;
 		}