CODA_KERNEL_VERSION
#define CODA_KERNEL_VERSION 0 /* don't care about kernel version number */
#define CODA_KERNEL_VERSION 1 /* The old venus 4.6 compatible interface */
#define CODA_KERNEL_VERSION 2 /* venus_lookup gets an extra parameter */
#define CODA_KERNEL_VERSION 3 /* 128-bit fids for realms */