[Unionfs] Changes in namei.h not consistent across releases

[Troy Volin]

Hi,
I'm trying to build unionfs (most recently 2.3.2, but it doesn't
matter) for kernel 2.6.18 (actually for RHEL 5, but we'll get to
that...).
There's a conflict between some of RedHat's Tux code (for in-kernel
httpd server "Tux") and unionfs.
I have just finished backing the Tux patches off of the RHEL5 kernel, (not 
fun!) but I'm still curious about the necessity of doing so.

Meanwhile, I noticed that the conflict isn't present in unionfs patches for 
every kernel version.
The specific conflict is the definition of LOOKUP_ONE (value 128) for the 
lookup event bitmask.

The patches for 2.6.23 and 2.6.24 do not (and have not) defined LOOKUP_ONE.
They also omit the corresponding check for LOOKUP_ONE in fs/namei.c.

I could not find anywhere in the code where that flag was getting set, so 
perhaps it was just ornamental anyway.

So my question is, is there something special that happened at 2.6.23 which 
made LOOKUP_ONE unnecessary?  Or is it safe to remove that code
from all the earlier releases (kernel releases, not unionfs releases) as 
well?

Thanks,
Troy