# Test Case: Extended Inode File Above 4 GiB

**Test ID**: TC024-extended-inode-large

## Objective

Verify a 64-bit extended `i_size` above 4 GiB without materializing a multi-GiB
payload, using deterministic FLAT_PLAIN hole reads at distant offsets.

## Fixture

Use `images/extended-large-hole.erofs` and
`expected/large-hole-zero-64k.bin`. Structured evidence asserts a 64-byte
inode, size `4294971393`, layout 0, `startblk=0xffffffffffff`, valid CRC, and
an all-zero content descriptor.

## Procedure

After mounting, run three bounded reads:

```sh
stat -f 'size=%z blocks=%b mode=%p' "$mnt/huge-sparse.dat"
./read_probe pread "$mnt/huge-sparse.dat" 0 65536 /tmp/tc024-start
./read_probe pread "$mnt/huge-sparse.dat" 2147483648 65536 /tmp/tc024-middle
./read_probe pread "$mnt/huge-sparse.dat" 4294905857 65536 /tmp/tc024-end
cmp /tmp/repo22-g1/expected/large-hole-zero-64k.bin /tmp/tc024-start
cmp /tmp/repo22-g1/expected/large-hole-zero-64k.bin /tmp/tc024-middle
cmp /tmp/repo22-g1/expected/large-hole-zero-64k.bin /tmp/tc024-end
sha256 /tmp/tc024-start /tmp/tc024-middle /tmp/tc024-end
```

Remove outputs, unmount, and detach.

## Expected Results

- Size is exactly `4294971393`, not truncated to 32 bits.
- Start, middle, and final 64 KiB ranges match the deterministic zero source.
- Reads are bounded, no large allocation/panic occurs, and cleanup succeeds.