Cache Manager

[Assar Westerlund]

wwshen at eecs.umich.edu writes:
>    1). Which directory do you implement the cache manager? arlad?

yes

>    2). As a cache manager, it needs to call RPC of the server to
>        get the file or directory and get a callback(where). At the same
>        time it need to provide the interface of RPC which is provided
>        to server(I notice the functions are defined in cmcb.c but
>        there are only three functions and according to "AFS-3 Programmer's
>        Reference: File Server/Cache Manager Interface" section 6.5.5
>        some functions such as RXAFSCB_GetCE.. are missing?).

The other functions are not needed.  They are mainly for debugging and
monitoring functions.  You must implement Probe, CallBack, and
InitCallBackState.

>    In addition, I am not clear about the callback. A cache will be 
> given a callback when it gets a file but when another client gets
> this file and closes it while the former client is using it. The
> server will revoke the file on the former client before it accepts
> the modification. But I am not clear what happens to the client
> still using this file. Will the server ignore all the modifications
> and close made by the former client??? Of course another open on
> the same file on the client will get the new version. 

No, many programs will get confused if files are changed while they
are reading (or executing them) so the local programs will not see the
modifications before the file is closed.

> PS. Could you add me to your mail list? Thanks.

You have been added.

/assar