On Thu, 18 Jun 1998, Adam D. Bradley wrote:
[snip]
> > But did anyone of those think on resizing in design stage ?
> > We do have a working LVM (Logical Volume Manager) which may
> > resize "Logical" block device on-the-fly ... so we only
> > need a filesystem to do so ...
>
> The LFS design is particularly easy to adapt to an LVM; enlarging the
> voluem simply means there are more clean segments available, and
> shrinking the volume simply requires you to clean any segments in the
> region you want to punch out. Whether they've seriously considered
> this, I don't know, although I don't recall seeing any clear
> statements on their web pages.
As far as dtfs is concerned (which is the working title of the LFS project
I'm currenty working on), dynamically resizing a partition with a dtfs
file system on it should be quite stragitforward as far as enlarging a
partition is concerned. (The support for dynamically resizing partitions
has influenced one early way of implementing dtfs that has been
discarded for other reasons.)
However, shrinking a partition is a different matter since the portion of
the partition to be removed could contain segments with live data.
IMHO this problem can be addressed by the cleaner: At first, lock all
free segments within the portion of the partition to be removed (to avoid
that they're used by the dtfs kernel implementation). Then ask the cleaner
to clean the offending used segments and lock them too. After that you'll
end up with no active data being in the part of the partition to be
removed.
As far as the other Linux/LFS projects are concerned, Kees Cook (who
originally run the LFS project located under collective.cpoint.net/lfs/)
has contributed to the design of dtfs. As far as the Yggdrasil LFS project
is concerned, they have quite a different approach in mind (similar to
Spiralog).
Christian
BTW: If you'd like to get in contact with me personally, please write
to czezatke@complang.tuwien.ac.at
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