svn commit: r198316 - head/sbin/tunefs

[Bruce Evans]

On Wed, 21 Oct 2009, Remko Lodder wrote:

> I'll try to implement your suggestions in a patch. Hopefully I'll have that 
> available later today. Can I send it over to you for reviewal so that
> we are sure to have the correct fix ?

It turned out to be mostly a kernel bug (I think -- I most don't use kernels
with the bug), so fixing it is not very easy.  The man page should just
say something like "... should (but does not <completely>) work on <active
file systems>".

<competely> should be replaced by a list of what doesn't work (but should)
and <active> should be replaced by something like "file systems mounted
r/o" (if that is what "active" should mean now).o

NetBSD's 2005 version says:

% BUGS
%      This program should work on mounted and active file systems.  Because the
%      super-block is not kept in the buffer cache, the changes will only take
%      effect if the program is run on unmounted file systems.  To change the
%      root file system, the system must be rebooted after the file system is
%      tuned.

"mounted and active" is as unclear as "active".  The rotted words about
rebooting seem to have come from here -- I just noticed that they are
very recent additions to FreeBSD's tunefs.8.  They were added in 2007
8 years after they stopped applying.  Bah, they aren't evem wrong like
that: allthough they are identical to NetBSD, they have a completely
different meaning.  In NetBSD they are related to the buffer cache as
dsecribed above, but in FreeBSD they are a special case for soft updates,
as described only in their log message.  It takes a full mount to get the
soft updates flag looked at, so the remount done by tunefs doesn't work
for changes to the soft updates flag.

So you can't just remove the second sentence, but must reword it to say
something relevant.

Bruce