VFAT i_pos value

[Kai Meyer]

I'm getting this error:
FAT: Filesystem error (dev sblsnap0)
     fat_get_cluster: invalid cluster chain (i_pos 523791)

I'm wondering if there was a way to figure out what sector is causing 
the error? I would like to try and track down what is changing that 
sector and fix the problem. Is there a straight forward way to convert 
i_pos to a sector value? I've been staring at the fat.c and fat.h code 
all morning, and I'm having trouble grok'ing the flow.

-Kai Meyer