Re: Wrapper fs Code (wrapfs)

[UZAIR LAKHANI <uzairr_bs1b@yahoo.com>]

--- Josef Sipek <jsipek@fsl.cs.sunysb.edu> wrote:

> On Tue, Aug 08, 2006 at 12:57:29AM -0700, UZAIR
> LAKHANI wrote:
> > --- Josef Sipek <jsipek@fsl.cs.sunysb.edu> wrote:
> > > The data is cached in the page cache.
> > 
> > Can we not by some way invalidate the old page and
> > force the kernel to read the actual page i.e. can
> we
> > not by any way by-pass the page cache for wrapfs
> read.
>  
> Currently, no. We (the stackable fs) would need to
> invalidate the page
> associated with ext3. ext3 won't invalidate our
> pages, so we would have to
> do it ourselves. To do that, we'd need some kind of
> callback so that when an
> ext3 page changes, we can propagate the change.

Thanks for the consistent and regular replies. Can you
please give some more details about the callback idea.
Do we will need to change the kernel code to implement
this callback idea but this will require kernel
re-compilation.

Can we solve the problem by implementing our own
address space operations.

One more question, as far as I know, distributed file
systems (e.g NFS) are also like a wrapper fs on server
side. How then these distributed file systems handle
cache coherency problem.

Thanks,
Uzair Lakhani
>  
> > How ext3 e.g. always get the updated data on read.
> 
> I am not sure what you mean.
> 
> Josef "Jeff" Sipek.
> 
> -- 
> The reasonable man adapts himself to the world; the
> unreasonable one
> persists in trying to adapt the world to himself.
> Therefore all progress
> depends on the unreasonable man.
> 		- George Bernard Shaw
> -
> To unsubscribe from this list: send the line
> "unsubscribe linux-fsdevel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at 
> http://vger.kernel.org/majordomo-info.html
> 


__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com