Re: [9fans] Re: tracking file modifiers (was: home, end ^h^j^k^l)

Re: [9fans] Re: tracking file modifiers (was: home, end ^h^j^k^l)

[rob pike]

It's just a field in the directory.

-rob

Re: [9fans] Re: tracking file modifiers (was: home, end ^h^j^k^l)

[Boyd Roberts]

From: "Paul C Lustgarten" <plus@cosym.net>
> Also, on the topic of managing WORM consumption,
> is there some way to protect the WORM from excess
> consumption, using the new muid or otherwise?

a mod may never hit the worm.  iirc there's a memory
cache, a magnetic cache and then the worm.  even munging
a block only gets a new copy of the block should it hit
the worm.

the file-server is cleverly constructed so that only
the tree and modified blocks chew up worm blocks.  put
the calculations in the chunk of code that burns worm
blocks.

> I'm thinking of scenarios such as programming mistakes
> where a user accidentally writes a bunch of stuff that
> they didn't intend and don't notice, or where they do
> something stupid like copying over the entire project's
> source tree in order to make a personal build with
> a couple of modified files.

you can't code against stupidity.  that is the 'knife school'
of design.  are you sure you want to cut that?

[9fans] Re: tracking file modifiers (was: home, end ^h^j^k^l)

[Paul C Lustgarten]

At 10:14 AM 5/19/2001 -0400, rob pike wrote:
> The -m flag reports the muid (modifier uid) of the file, as reported
> in the new 9P protocol.  This is the person who most recently modified
> the file, instead of the person who created it.

If I had a collection of projects using Plan 9, and wanted
to bill back file store (WORM) usage to those projects,
would this muid provide enough information to do so?
I'm willing to assume that each user is a member of only
one project.  And I don't care about daily cache usage -
I just want to allocate responsibility for consumption
of the blocks on the WORM, while having all the other 
benefits of sharing that WORM amongst those projects.

I'm imagining that the muid would make it easy to
handle the simple case of files that are modified by
just a single user (like me editing my lib/profile).
What about files written by multiple users (e.g.,
several developers editing a shared project file,
all within the same day), or append-only (log,
mailbox) files that have been extended by several
different users (again, within a single day)?

Also, on the topic of managing WORM consumption,
is there some way to protect the WORM from excess
consumption, using the new muid or otherwise?
I'm thinking of scenarios such as programming mistakes
where a user accidentally writes a bunch of stuff that
they didn't intend and don't notice, or where they do
something stupid like copying over the entire project's
source tree in order to make a personal build with
a couple of modified files.  I keep thinking of being
able to impose per-user quotas that would be enforced
by the system itself (as part of the nightly dumps?),
as a safety measure complementing the economic
incentive created by charging the projects for what
their users do consume.