[Sheepdog] [PATCH v6 7/8] collie: read the cached objects if any for collie operation

[MORITA Kazutaka]

At Sat, 31 Mar 2012 14:40:35 +0800,
Liu Yuan wrote:
> 
> On 03/31/2012 02:29 PM, MORITA Kazutaka wrote:
> 
> >> But we simply can't do it, since collie will issue RW requets without
> >> > the knowledge if we have cache enabled or not.
> > I don't still understand why we can't process collie requests with the
> > above way.  Can you give me an example for it?
> > 
> 
> 
> I assume who use collie doesn't know whether the Guest use object cache
> or not.
> 
> If the Guest use the cache, but collie issue a read request without
> SD_FLAG_CMD_CACHE flag, then this operation will cause the object cache
> to be removed.
> 
> Yes, we can add one more option to collie to specify whether we have
> cache or not and leave the policy of the cache to be made by users.

- Read requests:
  read from a object cache always when the cache exists

- Write requests:
  flush and remove a object cache if SD_FLAG_CMD_CACHE is not set

Isn't this okay for collie, too?

Thanks,

Kazutaka