(*) == default.
-norm_unmount (*) commit on unmount; the journal is committed
- when the file-system is unmounted so that the
- next mount does not have to replay the journal
- and it becomes very fast;
-fast_unmount do not commit on unmount; this option makes
- unmount faster, but the next mount slower
- because of the need to replay the journal.
bulk_read read more in one go to take advantage of flash
media that read faster sequentially
no_bulk_read (*) do not bulk-read