Re: [lustre mess] is mgc_fs_setup() reachable at all?

[Al Viro <viro@ZenIV.linux.org.uk>]

On Thu, Jul 18, 2013 at 11:40:16AM -0700, Nathan Rutman wrote:
> >>                }
> >>                RETURN(rc);
> >>        }
> >> What is going on here?  We cast something to struct super_block *?
> >> Where does it come from?  The function it's in is
> Well, addressing the "what's going on" question without getting into the larger philosophy,
> keys and values are used as a generic mechanism to pass various items between Lustre clients
> and servers.  In this case, a specific key should only have a value of "a superblock", and so this is 
> just a sanity check to make sure the value length is sane.  It should probably be more of an ASSERT,
> but we can't reasonably assert on remotely-supplied data.

What?  Excuse me, but have you seriously been intending to pass struct
super_block instances around?  Ones that are choke-full of pointers to
all kinds of things, not to mention a mutex, spinlock, etc.?

_THAT_ was going to be a remotely supplied data?  I really hope I've
misparsed what you said above...

And that still leaves the question about the code path that could lead to
execution of mgc_fs_setup().