[OpenAFS] Undelete support feedback request

Jeffrey Hutzelman jhutz@cmu.edu
Thu, 07 Dec 2006 13:46:29 -0500

On Thursday, December 07, 2006 01:34:50 PM -0500 Jeffrey Altman 
<jaltman@secure-endpoints.com> wrote:

> I would believe that what would be desired is a non-permanent delete
> in the r/w volume in which the file/directory would be marked with
> a new attribute that means deleted but not reclaimed.
> Files/directories would be automatically reclaimed as they bump up
> against their quota.
> New RPCs would be required to support the undelete operations:
>  * purge all deleted but unclaimed files/dirs
>  * undelete the specified file/dir
>  * list files/dirs that can be undeleted

Actually, we're only talking about files here.  A directory can't be 
deleted in the first place unless it's empty, and the undelete operation 
for an empty directory is the same as the directory creation operation.

Life gets interesting when multiple files with the same name have been 
deleted, but maybe you don't care about that (I would).

The mechanism for representing this would not be trivial to design, given 
requirements like preserving backward-compatibility of the directory format 
and not allowing the vnode index to grow without bound.

Inventing a new volume type would also be problematic, in terms of tracking 
the relationship between the new volume and the RW, handling mount points 
correctly, and also because Matt is proposing a new type of clone with 
different and much more complex semantics.

I suspect that the improvement over traditional backup volumes is 
relatively small, and while it would be a "cool" feature, I think there are 
probably others on which the time would be better spent.  Buy hey, it's 
your time, not mine...

-- Jeff