xfs_refcount_update
error = xfs_refcount_update(cur, &ext);
error = xfs_refcount_update(cur, &tmp);
error = xfs_refcount_update(cur, left);
error = xfs_refcount_update(cur, left);
error = xfs_refcount_update(cur, right);
DEFINE_REFCOUNT_EXTENT_EVENT(xfs_refcount_update);