[ENBD] proxing ioctl's

[Peter T. Breuer]

"A month of sundays ago Daniel Shane wrote:"
> > What was the file? I had a look at the ramfs driver, but they use
> > pages.
> 
> Its rd.c in drivers/block, in the do_rd_request() function. 

Yes, I just saw it in the train this morning. They use their own
make_request, and mark the buffer protected. I can do that ..

> All we need to do is mark the page undeletable, and when we close
> the connection to a server, just destroy the reserved buffers.

I'm not quite sure when one does this. They do as soon as they make the
request. If I don't also intercept the make, I will do it later. Maybe
even the appropriate opportunity is when I run endio.

I had a quick hack at the make_request code. I'll try various
strategies later. Or if I offer them to you, maybe you could try the
alternates.

> It looks like a 4 or 5 lines of code max to implement client 
> side journaling. I even think it would be more efficient that
> the current solution. 

Yes

Peter