err = -EINVAL;
if(strlen(backing_file) > sizeof(header->backing_file) - 1){
+ /* Below, %zd is for a size_t value */
cow_printf("Backing file name \"%s\" is too long - names are "
- "limited to %d characters\n", backing_file,
+ "limited to %zd characters\n", backing_file,
sizeof(header->backing_file) - 1);
goto out_free;
}