Sysinstall automatic filesystem size generation.

[Matthias Buelow]

Jon Dama wrote:

>Ironically, phk backed out the underlying support for this safety fix
> from the FreeBSD kernel b.c. it wasn't integrated into the softupdates
>code
>whereas in reality the proper course of action would have been to hook it
>in.  :-/

Can it be put into softupdates at all? From what I understand (which
is probably a rather sketchy idea of the matter), write barriers
work because they are only used here to separate journal writes
from data writes (i.e., to make sure the log is written, by flushing
the cache, before any filesystem data hits the platters). I've read
the softupdates paper some time ago and haven't found similar
sequence points where one could insert such flushing.  One would
have to "flush" all the time, either continuously or in very short
intervals, in order to keep the ordering, which then would amount
to the same effects as if one simply disabled the cache. But probably
I'm wrong here (I hope).

mkb.