diskless/unionfs panics

[Oleg Sharoiko]

On Sun, 1 May 2005, Jeff Roberson wrote:

JR>Yes, unfortunately this is only part of the problem.  The v_object can
JR>change on a unionfs vnode leading to inconsistent results for mmap/exec.
JR>This also causes problems for unionfs mounted on top of unionfs as the
JR>lower vp can also change v_object fields.  This was one advantage to the
JR>VOP based solution.  It would propagate all the way down the stack on each
JR>access.

So do I get it right that the problems can happen if file being execed or 
mmaped over unionfs will at the same time be changed on ufs (assuming that 
ufs was used to mount unionfs)? Does this mean that nullfs also have the same 
problem? But how can this problem be solved? And what is VOP based solution?

-- 
Oleg Sharoiko.
Software and Network Engineer
Computer Center of Rostov State University.