[OpenAFS-devel] Proposed change for handling backup volumes

[Harald Barth]

> If you're using my desktop machine for instance, I reserve the right as
> the owner of the machine to change it out from under you at my whim. On a
> timeshare system, of course you'd set it or unset it and be done.

:-) sure.

> > In ro volume -#foo-> in ro volume foo (if available, otherwise rw)
> > In rw volume -#foo-> in rw volume foo
> > In ba volume -#foo-> in ba volume foo (if available, otherwise rw)
> 
> only the last one should ever change.

Yes, only the last one is the one that changes.

> > In ro volume -%foo-> in rw volume foo
> > In rw volume -%foo-> in rw volume foo
> > In ba volume -%foo-> in rw volume foo
> 
> these stay the same.

Yes.

> > The folks that want to "get back" to the rw side of the universe
> > can allways use rw (%) mountpoints, which in backup volumes have
> > the same behaviour as type preserving (#) mountpoints.
> 
> you mean currently, yes?

Currently, yes.    

nneul> oh damn, I just screwed something up, quick - remount the .backup
nneul> volume so I have some time to fix it.

And then you want to traverse back into the "new" three for
mountpoints "further down". I see. I have never done it that way, I
have allways mounted the backup volume somewhere else and then copied
content back. When deleting and makeing a new mountpoint like you do,
I would not be sure what happens with processes with a CWD there?

> The real issue is semantics for a .backup tree, I think.

Yes.

I think that

#foo = stay in volume type if possible and cross over to rw if not
%foo = cross over to rw

is good. Is there any need for ?foo (for some "?") to cross over to
other volume types if available or is mounting #foo.backup and
#foo.readonly good enough?

Harald.