update

tests/TC158-48bit-compressed-blocks-hi.md

@@ -0,0 +1,45 @@
+# Test Case: 48-Bit Extended Compressed Block Count
+
+**Test ID**: TC158-48bit-compressed-blocks-hi
+**Category**: Inode and VFS Metadata
+**Priority**: Critical
+**Regression**: Extended compressed inodes ignored `i_nb.blocks_hi`
+
+## Objective
+
+Verify Linux-compatible union decoding for an extended compressed inode with
+`blocks_hi=1`, and exact FreeBSD `va_bytes`/`st_blocks` values through direct and
+file-handle/NFS-style getattr paths.
+
+## Fixture
+
+`final_review_fixtures.py` emits `compressed-blocks-hi.erofs` as a small seed.
+Its manifest records `blocks_lo`, `blocks_hi`, block size, exact `va_bytes`,
+`st_blocks`, and the required sparse provider size. Verify the seed SHA256 before
+extending it in the guest.
+
+## Procedure
+
+1. Copy the seed in the guest and create the qualified sparse provider:
+
+   ```sh
+   cp compressed-blocks-hi.erofs compressed-blocks-hi-sparse.erofs
+   truncate -s 17592186056704 compressed-blocks-hi-sparse.erofs
+   ```
+
+2. Attach and mount it read-only with the exact module.
+3. Run `final_review_probe stat-blocks` with the manifest's expected value. The
+   helper compares `stat` and `getfh`/`fhstat` results.
+4. Use an FBT entry/return probe on `erofs_getattr` to capture
+   `a_vap->va_bytes`; require the manifest value.
+5. Read at least one block of `/compressed-blocks.bin`, then unmount, detach,
+   shrink/remove the sparse file, unload DTrace, and unload EROFS.
+
+## Expected Results
+
+- `data_blocks == (1ULL << 32) | blocks_lo`.
+- `va_bytes == 17592186052608`.
+- Direct `stat` and file-handle `fhstat` both report
+  `st_blocks == 34359738384`.
+- The compressed file remains readable; the high block count is allocation
+  metadata, not a physical read address.