nvf_rename
rval = nvf_rename(nvf_curr_filename, nvf_prev_filename);
rval = nvf_rename(NVF_TMP_FILENAME, nvf_curr_filename);
(void) nvf_rename(nvf_curr_filename, corrupt_filename);
(void) nvf_rename(nvf_prev_filename, corrupt_filename);
static int nvf_rename(char *oldname, char *newname);