I use Reiserfs for all of my partitions, and soon after upgrading to 
linux-2.4.18-pre6-O1J5 I started getting massive data corruption in my 
/etc directory, strangely enough ONLY in that directory.  I've attached 
the .config I used for that kernel, unfortunately I have been unable to 
do further testing, because at the same time I had problems on my 
production box, and had to use my toy box to fix it (so I couldn't 
afford to have my toy box down any more).

Hope this is helpful/interesting!

--Brandon