[note: this was not a sparse file and I wasn't using --apparent-size] On a 1TB local btrfs file system, I found a log file for which du reported a size of 1.2 petabytes. Quite surprising for a moment, then I remembered btrfs's "compression".
Should we teach du to report compressed size? Via a new option? Or make it report *that* size by default, and add a new option to report the other number. Or should we just view this as a btrfs+compression infelicity? Otherwise, du provides no way of seeing how much of the actual disk space is being used by such FS-compressed files.
