SECRM, UNRM, COMPR flags

Hi,

in ext4 we have these SECRM, UNRM, COMPR flags which users can set, they
can read them, but which actually don't do anything. This is actually
somewhat confusing - e.g. I've just got report about one tool which
apparently sets SECRM flag on a file in a hope that it is somehow safer.
Also this is a waste of flags.

I've checked other filesystems (xfs, btrfs) and they report EOPNOTSUPP if
these flags are not really supported. Should not we do the same in ext4? I
know there is a concern about breaking userspace but since other major
filesystems already behave this way I think there is a good chance tools
handle this reasonably... What do people thing?

								Honza

-- 
Jan Kara [off-list ref]
SUSE Labs, CR