ptr->len = ptr->offsets[1];
ptr->crc32 = crc32buf((void *) &(ptr->flag_version), ptr->len - offsetof(struct trx_header, flag_version));
msync(ptr,len,MS_SYNC|MS_INVALIDATE);
ptr->len = ptr->offsets[1];
ptr->crc32 = crc32buf((void *) &(ptr->flag_version), ptr->len - offsetof(struct trx_header, flag_version));
msync(ptr,len,MS_SYNC|MS_INVALIDATE);