v0.13.37: Pass 1 is pure ECC-block sweep — read 32 sectors, fail → skip, no single-sector reads

This commit is contained in:
MattJackson
2026-04-28 21:08:58 -07:00
parent 13eb4331b6
commit 52b8522a75
4 changed files with 375 additions and 147 deletions
+15 -36
View File
@@ -351,7 +351,7 @@ fn test_file_sector_reader_round_trip() {
//
// Per RIP_DESIGN.md §2.1 + §3: Disc::copy must reach the end of the disc
// regardless of how many reads fail. The only legitimate early exit is the
// halt flag. With `skip_on_error + skip_forward` and a reader that returns
// halt flag. With `skip_on_error` and a reader that returns
// Err for every read, Pass 1 must:
// - mark every sector NonTrimmed (so Pass 2 can retry them)
// - return cleanly (no panic, no hang)
@@ -424,7 +424,7 @@ impl SectorReader for FailingSectorReader {
#[test]
fn test_disc_copy_completes_full_disc_with_failing_reader() {
// 1024 sectors = 2 MB. Reader fails every read. With skip_on_error +
// skip_forward, Pass 1 must mark every sector NonTrimmed and return
// skip_on_error, Pass 1 must mark every sector NonTrimmed and return
// cleanly — no bail, no hang.
let capacity_sectors: u32 = 1024;
let total_bytes: u64 = capacity_sectors as u64 * SECTOR_SIZE as u64;
@@ -439,7 +439,7 @@ fn test_disc_copy_completes_full_disc_with_failing_reader() {
let opts = CopyOptions {
decrypt: false,
skip_on_error: true,
skip_forward: true,
..Default::default()
};
@@ -521,7 +521,7 @@ fn test_disc_copy_halts_promptly_on_failing_reader() {
let opts = CopyOptions {
decrypt: false,
skip_on_error: true,
skip_forward: true,
halt: Some(halt),
..Default::default()
};
@@ -553,16 +553,9 @@ fn test_disc_copy_halts_promptly_on_failing_reader() {
// ── 8. Hysteresis recovers data the drive can read individually ──────────
//
// Empirically observed on the LG BU40N: in damaged regions the drive fails
// multi-sector READ commands but reads each sector cleanly when asked one
// at a time. Disc::copy's hysteresis state machine (0.13.22, replaces the
// 0.13.21 bisect-on-fail) drops to bpt=1 on the first multi-sector failure
// and stays there until BPT1_EXIT_THRESHOLD consecutive good single-sector
// reads, then returns to bpt=batch.
//
// Fixture: a reader that returns Err for any read with count > 1, and Ok
// for count == 1. The full disc must recover via the bpt=1 path with
// 100 % bytes_good outcome.
// Pass 1 reads in batch (32 sectors = 1 ECC block). Failed blocks are marked
// NonTrimmed for Pass 2 recovery. This test verifies that a reader where every
// multi-sector read fails produces all NonTrimmed output with zero bytes_good.
struct BlockSizeFailingReader {
capacity: u32,
@@ -577,15 +570,11 @@ impl SectorReader for BlockSizeFailingReader {
_recovery: bool,
) -> Result<usize> {
if count == 1 {
// Single-sector reads succeed — fill the sector with a marker.
for chunk in buf.chunks_mut(SECTOR_SIZE) {
chunk.fill((lba & 0xff) as u8);
}
Ok(buf.len())
} else {
// Multi-sector reads fail with the BU40N's signature: CHECK
// CONDITION + MEDIUM ERROR. The hysteresis must dispatch on
// this as marginal-read and drop to bpt=1.
Err(libfreemkv::error::Error::ScsiError {
opcode: libfreemkv::scsi::SCSI_READ_10,
status: libfreemkv::scsi::SCSI_STATUS_CHECK_CONDITION,
@@ -604,13 +593,7 @@ impl SectorReader for BlockSizeFailingReader {
}
#[test]
fn test_disc_copy_hysteresis_recovers_via_single_sector_reads() {
// 256 sectors = 0.5 MB. Reader fails any multi-sector read but
// succeeds on bpt=1. The hysteresis path must drop to Single mode on
// the first multi-sector failure and recover every sector at bpt=1.
// Stays in Single mode until BPT1_EXIT_THRESHOLD reached (10 000
// sectors); since this disc is only 256 sectors we never re-enter
// Block mode, which is fine — every sector still recovers.
fn test_disc_copy_marks_failed_ecc_blocks_as_nontrimmed() {
let capacity_sectors: u32 = 256;
let total_bytes: u64 = capacity_sectors as u64 * SECTOR_SIZE as u64;
@@ -626,7 +609,6 @@ fn test_disc_copy_hysteresis_recovers_via_single_sector_reads() {
let opts = CopyOptions {
decrypt: false,
skip_on_error: true,
skip_forward: true,
..Default::default()
};
@@ -637,20 +619,17 @@ fn test_disc_copy_hysteresis_recovers_via_single_sector_reads() {
let _ = std::fs::remove_file(&iso_path);
let _ = std::fs::remove_file(libfreemkv::disc::mapfile_path_for(&iso_path));
// Bisect must recover every sector — the drive could read each one
// individually, and our algorithm must descend to that.
assert_eq!(
result.bytes_good, total_bytes,
"bisect-on-fail must recover every sector via single-sector reads. \
Got bytes_good={} of total {}",
result.bytes_good, 0,
"Pass 1 should have 0 bytes_good when all batch reads fail. Got {} of {}",
result.bytes_good, total_bytes
);
assert_eq!(
result.bytes_pending, 0,
"no sectors should be left NonTrimmed after a successful bisect"
assert!(
result.bytes_pending > 0,
"all sectors should be NonTrimmed pending Pass 2"
);
assert!(
result.complete,
"complete=true expected when every sector recovered"
!result.complete,
"complete=false when sectors remain NonTrimmed"
);
}