erofs-freebsd-out-tree/tests/TC025-nlink1-handling.md

Test Case: Compact Inode Link-Count Rules

Test ID: TC025-nlink1-handling

Objective

Compare explicit compact link counts, bit-4 single-link encoding, hard links, and directory link counts without conflating directory dot omission.

Fixture

Use images/compact.erofs and images/compact-nlink1.erofs. Evidence asserts explicit single.txt i_nb=1, patched bit 4 plus i_nb=0x1234, identical hard-link NID with i_nb=2, and explicit directory nlink.

Procedure

Mount each image separately and record:

stat -f '%N ino=%i nlink=%l mode=%p' \
  "$mnt/single.txt" "$mnt/hard-a.txt" "$mnt/hard-b.txt" "$mnt/dotdir"
cmp /tmp/repo22-g1/source/compact/single.txt "$mnt/single.txt"
cmp /tmp/repo22-g1/source/compact/hard-a.txt "$mnt/hard-a.txt"
cmp "$mnt/hard-a.txt" "$mnt/hard-b.txt"

Unmount and detach before attaching the second image.

Expected Results

• Baseline and patched single.txt both report nlink 1 for different valid encodings.
• hard-a.txt and hard-b.txt share one inode and report nlink 2.
• dotdir uses its explicit directory link count; all data compares pass.