[tahoe-dev] How does file deletion work?

[Shawn Willden]

On Monday 13 July 2009 10:29:31 am Rufus Pollock wrote:
> Right: so deleting from a directory means unlinking from that
> directory. If it is linked from elsewhere it won't be deleted and even
> if i unlink from all directories if there's a read-cap out there it
> will still stay so how do I *really* delete it for sure

You can't!

> But how do I (or tahoe) know if someone is holding a read or
> write-cap? (And when we say someone we can't mean anything I've passed
> the read-cap to, we've got to mean something that's connected to the
> grid like another node right?)

Tahoe can't in general know about all read or write caps held outside of Tahoe 
dirnodes.  If you're holding an unlinked read cap which you don't want to get 
deleted, you have to periodically contact the servers holding the shares 
to "renew the lease".  Without that, the servers will probably eventually 
reclaim the space.

> Also how quickly once all read or write-caps have gone does deletion
> happen (is this a GC thing?).

It's a GC thing, and I'm not sure what the state of the GC implementation is.  
I probably should have just let someone who does know respond.

	Shawn.