func (d *dataUsageCache) deleteRecursive(h dataUsageHash) {
	if existing, ok := d.Cache[h.String()]; ok {
		// Delete first if there should be a loop.
		delete(d.Cache, h.Key())
		for child := range existing.Children {
			d.deleteRecursive(dataUsageHash(child))
		}
	}
}

// dui converts the flattened version of the path to madmin.DataUsageInfo.
// As a side effect d will be flattened, use a clone if this is not ok.