# Test Case: Superblock Parsing

**Test ID**: TC014-superblock-parse

## Objective

Verify mandatory superblock fields at their real on-disk offsets and compare
the mounted values exposed by FreeBSD.

## Fixture

Use `images/compact.erofs`, its image hash, `fixture-evidence.txt`, and
`tests/statfs_probe.c`.

## Procedure

Host inspection:

```sh
od -An -tx4 -j 1024 -N 4 /work/build/repo22-g1/images/compact.erofs
od -An -tu1 -j 1036 -N 1 /work/build/repo22-g1/images/compact.erofs
od -An -tu2 -j 1038 -N 2 /work/build/repo22-g1/images/compact.erofs
od -An -tu8 -j 1040 -N 8 /work/build/repo22-g1/images/compact.erofs
od -An -tu4 -j 1060 -N 8 /work/build/repo22-g1/images/compact.erofs
dump.erofs -s /work/build/repo22-g1/images/compact.erofs
python3 tests/erofs_fixture.py inspect /work/build/repo22-g1/images/compact.erofs
```

Mount the same hashed image in FreeBSD, then run:

```sh
./statfs_probe "$mnt"
stat -f 'root_ino=%i type=%HT' "$mnt"
mount -p | awk -v p="$mnt" '$2 == p'
```

## Expected Results

- Magic is `0xe0f5e1e2`, `blkszbits=12`, and checksum validation is true.
- Root NID, block count, and inode count agree with root `stat` and
  `statfs_probe`; filesystem type is `erofs` and read-only.
- No parser error appears in the dmesg delta; cleanup succeeds.