__fdb_entry
struct __fdb_entry *fe = buf;
memset(buf, 0, maxnum*sizeof(struct __fdb_entry));
if (maxnum > PAGE_SIZE/sizeof(struct __fdb_entry))
maxnum = PAGE_SIZE/sizeof(struct __fdb_entry);
size = maxnum * sizeof(struct __fdb_entry);
array_size(num, sizeof(struct __fdb_entry))))
if (off % sizeof(struct __fdb_entry) != 0)
count / sizeof(struct __fdb_entry),
off / sizeof(struct __fdb_entry));
n *= sizeof(struct __fdb_entry);