vn_fullpath()

[Igor Shmukler]

Robert and David,

Thank you for your help.

> It depends a lot on the requirements.  There are some nasty edge cases
> where the process of determining a name for an object can be quite
> expensive.  Here's one of them:
> 
>   ln /usr/local/etc/apache/httpd.conf /usr/local/etc/apache.old/httpd.conf
>   reboot
>   apachectl start
>   rm /usr/local/etc/apache/httpd.conf
> 
> Now generate the name of the file that Apache has open.  Note that you
> can't just look in the name cache, because the object has a name but the
> name used to open the object has been invalidated.  And UFS even knows it
> has a name, because the link count remains non-zero when the unlink of one
> of the names occurs -- but the only way it can find the other name is to
> search the file system. 
> 
> So the first thing to do is to decied what your requirements are: are you
> willing to fail in the edge cases like the above?  If so, life is a lot
> easier :-). 

I guess I am willing to fail :). Perhaps in some distant future, we will look into the nasty corner cases, 
but for now, as long as I get a name, it will do. We don't even mind the hardlinks so much, but we cannot 
afford to use existing vn_fullpath() because it does not guarantee "anything".

Thank you,

Igor