> Trevor Johnson wrote:
> >
> > > I've been thinking about a number of ways to implement
> > > an ``overlay'' filesystem for Linux -- a filesystem
> > > that you could mount over ordinary r/o media like CD-ROMs
> > > and NFS r/o partitions, which would allow you to write
> > > and just store the diffs to the original data.
> >
> > Someone did something like this awhile back:
> >
> > http://sunsite.unc.edu/pub/Linux/system/filesystems/ifs-5.1a-module-for-1.1.88.gz
> > ___
> > Trevor Johnson
>
> I started adding code for ``copylinks'' to 2.1.77 last
> night. I don't know yet whether these are a good idea :-)
> but I'll probably implement them, play with them to
> see if they do what I want, and then if they work out
> distribute the patches. Copylinks may be much more general
> purpose than IFS (and IFS needs a lot of work to integrate
> it into 2.1 - eg. dcache changes).
Are you thinking of copying the file completely when it is written to, or
on a block by block basis ? I could definately think of a few uses for an
overlay filesystem ......
P.