WO-2 (delete SectorReader trait):
- The 0.18 trait split into SectorSource (read-only) and SectorSink
(write-only) is final; the legacy SectorReader alias was a bridge.
- Renames every internal &mut dyn SectorReader (~25 sites) to
&mut dyn SectorSource. The trait method capacity() becomes
capacity_sectors() with a default of 0 (preserves SectorReader's
default-0 behavior).
- Deletes the SectorReader trait, its blanket-to-Source bridge, and
the FileSectorReader type alias. Adds explicit forwarding impls
for Box<dyn SectorSource> and &mut dyn SectorSource so generic
decorators like DecryptingSectorSource<S: SectorSource> compose.
WO-3a (extract Disc::patch):
- Moves Disc::patch (1230 lines) and bytes_bad_in_title from
disc/mod.rs into disc/patch.rs as a split inherent impl. Zero
behavior change — pure mechanical relocation. disc/mod.rs drops
from 3,945 to 2,714 LOC.
WO-6 (partial):
- Deletes src/labels/png_filenames.rs — was a 72-LOC stub with
detect() returning false, never wired into the PARSERS registry.
project docs doc drift fixes (audited 2026-05-13):
- JUMP_BASE_SECTORS: 256→1024 (64 MB base for UHD, not 8 MB)
- PASSN_DAMAGE_THRESHOLD_PCT: 12→6
- PASSN_SKIP_SECTORS_BASE: 64→32
- MAX_RANGE_SECS=180: replaced by proportional range_sectors × 25,
capped at RANGE_BUDGET_CAP_SECS=1800.
scan_with() collapsed every failure path from resolve_encryption() into
None via .ok(), so callers couldn't tell the difference between "no
KEYDB found", "KEYDB failed to parse", "disc hash not in KEYDB and
fallback derivation failed", "AACS files unreadable on disc", and a
handshake that rejected every host cert. autorip's UI was stuck
printing "no decryption keys found (check KEYDB)" for all of them,
which is a particularly bad message when the user has actually loaded
a KEYDB and the real failure is something else.
Changes:
- New pub field Disc.aacs_error: Option<Error>. Populated by scan_with
whenever encrypted && aacs.is_none(). Sentinel KeydbLoad path
"<no keydb in search paths>" distinguishes the no-keydb case from
a real load failure without adding a new Error variant (which would
be a breaking change for downstream exhaustive matches).
- tracing::warn in scan_with at scan_aacs_resolve_failed and
scan_aacs_no_keydb, with error_code and keydb path for grepping.
- tracing in do_handshake: keydb load failure, host-cert exhaustion
(with cert count and last error code), VID read failure post-auth,
and a debug-level success log. Lets us see whether handshake even
got off the ground for a given disc.
Test fixtures updated to set aacs_error: None.
The 'All probes failed — possible wedge condition' log fired during patch
probing whenever 10+ consecutive failures hit AND a probe sweep at the
local zone returned 0 successes. This was distinct from the read_error.rs
'wedge_transition' log that fires when the SCSI sense family ACTUALLY
flips into Hardware/IllegalRequest fast-fail mode.
Two logs both saying 'wedge' caused operator confusion during the
2026-05-11 Dune Pt 2 wedge investigation — was the drive wedged, or was
it just a zone of fully-bad sectors? They mean different things.
Relabel to 'patch_zone_fully_bad' with explicit pointer to read_error.rs
for the canonical wedge detection. Same triggering condition; just clearer
wording in the log stream.
Pass N now reads at 32 sectors per attempt and drops to 1 only on
batch-read failure to probe each sector individually. After 16
consecutive clean single-sector reads it climbs back to 32. Net
effect: NonTrimmed regions walk ~32x faster in clean stretches
without sacrificing per-sector recovery quality — the drop-to-1
retry from the same cursor position guarantees every sector in a
failed batch is individually attempted.
Design contract:
- A batch-read failure (count > 1) is NOT a recorded failure: no
NonTrimmed mark, no consecutive_failures bump, no damage_window
push, cursor stays put. We just drop current_batch to 1 and the
loop re-attempts the same position at single-sector granularity.
- A single-sector failure (count == 1) follows the existing path:
NonTrimmed mark, consecutive_failures++, damage_window.push(false),
post-failure pause, wedge probes.
- Backtrack always at count=1: this path fills a gap that the main
loop's damage-window skip jumped over. Using batched reads there
would lump good sectors into NonTrimmed marks when the gap
contains even one bad sector.
State machine adds:
- `initial_batch` (from opts.block_sectors, default 32 in patch_internal)
- `current_batch` (mutable, starts at initial_batch, drops to 1 on
batch failure)
- `consecutive_singles_ok` (counter, resets on upscale + failure)
- `ADAPTIVE_UPSCALE_THRESHOLD = 16` (matches sweep's pattern for
"16 consecutive good = back to fast mode")
Tests:
- pass_n_size_aware_skip.rs PatternedSectorReader now fills each
sector with its OWN LBA byte (not the starting LBA's byte). This
matches real drive behavior — the pre-0.18.13 fixture's
"fill whole batch with one byte" was a shortcut that only worked
when patch read 1 sector at a time. Existing recovery-quality
assertions all still pass under adaptive batching.
User spec: "try 32, pass, great, fail -> do 1 sector"
User design call after watching Pass 2 mark ~20 KB as "Cosmetic"
(permanently Unreadable) after just 10 retries within a single pass:
"i think it's good or maybe until all passes are done. then it's
gone."
That contradicts what the multi-pass design promises a user. The
project goal in project docs is "recover 100% of readable data from any
optical disc, automatically." Marking sectors Unreadable after a
SINGLE pass's per-range retry budget gives up on sectors that
subsequent passes might recover — drive reads are stochastic, the
sector that fails 10 times in Pass 2 may succeed on attempt 1 in
Pass 3 after temperature / bus state / prior-read patterns shift.
The patch.rs doc comment already noted ~36% of patch-marked
Unreadable sectors turned out to be readable in re-rip experiments.
Three sites in `Disc::patch` were emitting `PatchItem::Unreadable`
mid-pass:
- backtrack hit damage (line ~2659)
- all-retries-exhausted on a single LBA (line ~2846)
- redundant second mark after the wedge-suspicion log (line ~2970)
All three now emit `PatchItem::NonTrimmed` instead. Failed bytes
stay "maybe" (NonTrimmed) so the next pass gets another shot. The
per-range skip-limit (10) and per-pass wedge-threshold (50) still
bound time-per-pass; they just no longer turn the bytes terminal.
The `PatchItem::Unreadable` variant stays in the enum (with
#[allow(dead_code)]) because the orchestrator-side end-of-recovery
promotion will use it: autorip, after the final retry pass
completes, scans the mapfile and promotes still-NonTrimmed →
Unreadable. That promotion lands in a follow-up commit on the
autorip side — separable from this libfreemkv change.
Loss accounting unchanged: `bytes_pending + bytes_unreadable` is
the "lost or pending" total that `abort_on_lost_secs` consults
(disc/mod.rs:1327). Moving bytes from one bucket to the other
mid-pass doesn't affect whether the rip would abort; it only
affects display (UI shows "Maybe" vs "Cosmetic") and whether
subsequent passes retry the bytes (the actual fix).
Test update: `test_pass_progress_separates_unreadable_from_pending`
was renamed to `test_pass2_leaves_failed_reads_as_pending_not_unreadable`
and rewritten to assert the new invariant — Pass 2 leaves all
failed bytes as bytes_pending (no mid-pass Unreadable promotion).
Original assertions were checking the pre-design-call behavior.
Precommit (cargo +1.86 fmt + clippy + test) green.
Wires the existing PassSummary infrastructure (in read_error.rs as
of a832bad) into the sweep loop's exit path. One INFO log line per
Pass 1 completion gives operators an at-a-glance damage profile
without grepping per-error WARN lines:
INFO pass1_summary total_reads_ok=384521 total_errors=5
zones_entered=1 jumps_taken=2
bytes_good=38_725_644_288 bytes_pending=46_GB
copy_elapsed_ms=1751650
Particularly useful for post-mortem analysis when combined with
the per-error structured WARN logs (ms_since_last_error /
ms_since_last_success / sense_family / wedge_transition) shipped
in 0.18.10. Single line tells you the pass shape; preceding WARN
lines tell you the per-error detail.
Pass N (Disc::patch) intentionally NOT covered in this commit —
Pass N has its own retry-budget summary semantics that warrant a
separate design pass. Pass 1 sweep is where wedge incidents
originate, so it gets the diagnostic surface first.
Staged for 0.18.11. 0.18.10 already shipped the per-error WARN
layer; this is the finishing companion log.
Complements the wedge-skip backstop (fbdb50c) with proactive
avoidance so we don't HIT the wedge in the first place. User's
take after seeing the Dune Pt 2 rip wedge at 48%: 'we shouldn't be
wedging.'
Empirical observations from the 23:09:12-23:09:55 wedge timeline:
5 read errors over 43 s, ~8 s apart (drive's own ECC recovery
takes 5-10 s per failure). Not 'hammering' in any usual sense,
but cumulative firmware-state buildup over 5 in-cluster errors
was enough to tip the BU40N into wedge mode at the 5th error.
Damage cluster spanned ~140 MB (LBAs 19.898M-19.965M). Current
damage-jump base of 256 sectors × batch=32 = 16 MB first jump,
doubling to 32 MB, 64 MB... Each jump landed BACK INSIDE the
140 MB cluster, exposing the drive to MORE in-cluster errors.
Two avoidance levers:
1. Inter-error pause on Pass 1 (PASS_1_FAIL_PAUSE_SECS = 5 s):
pre-fix Pass 1 ran pause_secs=0 on all errors to 'zoom past'
damage zones. Successful reads still zoom at zero pause — the
pause applies only to FAILED reads, giving the drive's firmware
cool-down between cluster exposures. Cost: ~5 s per scattered
failure (~30-60 s total on a damage cluster); trivial vs.
crashing the rip at 48%.
2. Larger damage-jump base (JUMP_BASE_SECTORS = 1024, up from
256): first jump at batch=32 now covers 64 MB instead of 16 MB,
second jump 128 MB instead of 32 MB. Two jumps clear 192 MB —
well past most single-cluster damage patterns. Smaller jumps
were landing inside the cluster and adding to the wedge counter.
Plus a halt-aware sleep helper (sleep_secs_or_halt) so the new
inter-error pause doesn't degrade halt response time. Halt poll
granularity 100 ms — halt fires within ~100 ms regardless of
remaining pause time. Updated three sleep call sites in disc/mod.rs
(SkipBlock pause, JumpAhead post-pause, Retry pause).
The wedge-SKIP backstop (fbdb50c) stays — combined with this
avoidance work, the flow becomes:
damage cluster encountered →
pause 5 s, mark NonTrimmed →
second failure →
pause 5 s, mark NonTrimmed →
...
threshold hit →
damage-jump 64 MB (clears 95% of clusters) →
if jump lands in another cluster: 128 MB next jump →
only if drive STILL wedges after all this:
wedge-skip kicks in (1 GB jump + 30 s cooldown × 16 budget)
Tests:
pass_1_pauses_briefly_on_skip_for_wedge_avoidance — locks the
new 5 s pause behavior in place (replaces the old pause=0 test).
integration test threshold bumped from 5 s to 60 s with comment
explaining the new bound is 'not infinite' rather than
'milliseconds-fast'.
All 433+ tests green on cargo +1.86 fmt + clippy + test.
Precommit green.
The 0.18.4 commit landed with rustfmt diffs in the new
canonical_order tests because my local validation script piped
'cargo fmt --check' to 'tail -1', masking the diff output and
reporting green when fmt was actually unhappy. CI's lint job
caught it immediately. No code change — pure formatting.
Disc::titles previously sorted purely by duration_secs descending,
which puts a play-all virtual playlist at index 0 on UHDs that ship
one. Such playlists reference the same source clips multiple times
for seamless alternate-angle / alternate-ending playback and report
inflated duration AND inflated size_bytes that exceeds the disc's
physical capacity.
Concrete observed case (The Amateur 2025 4K UHD, 58.5 GB BD-100):
Title 1 — 00020.mpls — 4h13m — 92.4 GB — 253 clips ← impossible
Title 2 — 00800.mpls — 2h02m — 57.2 GB — 1 clip ← the movie
92.4 GB > 58.5 GB capacity is proof of clip double-counting. With
the duration-only sort, freemkv -t 1 / disc.titles.first() / autorip's
main-feature picker all selected the 4-hour composite instead of the
2-hour movie.
New canonical_title_order:
1. Real titles (size_bytes <= capacity_bytes) before virtual
composites — capacity gate is hard physical truth.
2. Among real titles, fewer clips first (1-clip wins as the
canonical main feature; multi-clip is either chapter-stitched
or composite).
3. Tiebreak on longer duration first.
Behaviour:
- Non-branching discs: unchanged. The longest 1-clip title is
already the movie.
- Branching UHDs: virtual composite drops to the back, the real
movie surfaces at index 0.
Comparator exposed as Disc::canonical_title_order for downstream
consumers that need the same logic on custom title sets.
Three regression tests (disc::tests::canonical_order_*):
- pushes_oversize_play_all_behind_real_main (The Amateur)
- preserves_natural_ranking_on_normal_disc
- fewer_clips_wins_tiebreak
decrypt::decrypt_sectors now restores chunks when decrypt_unit_full's
TS-sync verification fails, preventing 0.18.1's silent corruption of
MPLS/CLPI navigation files when DecryptingSectorSource decorates the
sweep reader. Fixes E6009 NoStreams on info iso:// for AACS-encrypted
UHDs ripped without --raw.
Disc::sweep progress takes max(snapshot.bytes_good, bytes_done) so
the user-visible counter never regresses below what the producer has
already sent.
Round 3 step 1: lift the visibility on the two flat rip-phase verbs
so consumers (autorip + freemkv CLI) can call them directly instead
of going through Disc::copy's multipass dispatcher. Also lift their
option/outcome types and re-export at crate root.
- fn sweep -> pub fn sweep (with rustdoc explaining its role)
- fn patch -> pub fn patch (ditto)
- pub(crate) struct SweepOptions -> pub struct SweepOptions
- pub(crate) struct PatchOpts -> pub struct PatchOptions (renamed
for consistency — both are 'Options')
- pub(crate) struct PatchOutcome -> pub struct PatchOutcome
- libfreemkv::{SweepOptions, PatchOptions, PatchOutcome} re-exports
at crate root.
Disc::copy still exists and still calls Disc::sweep / Disc::patch
through the now-private sweep_internal / patch_internal wrappers.
Migration of the two autorip callers + the freemkv CLI's
disc_to_iso to direct sweep/patch is a follow-up; once those land
Disc::copy + CopyOptions + CopyResult delete in the same commit.
See (internal)/memory/0_18_redesign.md and
0_18_round3_migration_audit.md.
Single contributor: MattJackson.
existing call sites — sweep producer and DiscStream demux
Round 1 shipped the DecryptingSectorSource decorator
(libfreemkv/src/sector/decrypting.rs) but the existing decrypt
sites kept calling crate::decrypt::decrypt_sectors inline. This
commit migrates both:
- Disc::sweep (disc/mod.rs): producer wraps the input reader
in DecryptingSectorSource::new(reader, keys) before the read loop.
The inline decrypt_sectors call goes away — read_sectors yields
plaintext directly.
- DiscStream (mux/disc.rs): constructor wraps the underlying
Box<dyn SectorReader> in DecryptingSectorSource so the internal
fill_extents / read path sees plaintext bytes. The DecryptKeys
field stays on DiscStream for metadata-side use; it just no
longer drives decryption.
Disc::patch carried the same inline decrypt step at three call
sites (main read, backtrack read, non-NOT_READY retry read). All
three migrated onto the same wrapping for a single audit surface.
Two small support changes carry the migration without touching
the round-1 decorator shape:
- sector/mod.rs gains specific SectorSource impls for
&mut dyn SectorReader and Box<dyn SectorReader>, mirroring
std's Read forwarding pattern. Generic blankets would conflict
with the existing SectorReader → SectorSource blanket under the
orphan rule (downstream could impl SectorReader for &mut U), so
the impls are scoped to the dyn-trait shape we actually consume.
- sector/decrypting.rs gains DecryptingSectorSource::set_keys so
DiscStream::set_raw() can flip the wrapped reader to a
DecryptKeys::None pass-through without rebuilding the decorator
(which would require moving the inner Box out from behind &mut self).
After this commit, grep `decrypt_sectors` in src/ shows the
function definition, its single use inside DecryptingSectorSource,
plus comments only. One audit surface for AACS / CSS / passthrough
correctness.
Behaviour-preserving: same plaintext bytes flow through; the only
difference is which type owns the decrypt step.
See (internal)/memory/0_18_redesign.md.
Single contributor: MattJackson.
Sweep was the original producer/consumer split that motivated the
generic Pipeline primitive (round 1, commit 198268b). Now that
Pipeline + Sink exist, sweep stops shipping its own bespoke
threading.
- New SweepSink: Sink<WorkItem> impl in src/disc/sweep.rs. Owns
WritebackFile + Mapfile + ProgressSnapshot back-channel. apply()
carries the file-write + mapfile.record per WorkItem; close()
drains writeback, fsyncs, flushes mapfile.
- Disc::sweep: constructs SweepSink, calls Pipeline::spawn_named
(so the consumer thread keeps showing up as
freemkv-sweep-consumer), sends WorkItems, calls pipe.finish().
The producer-side ReadCtx state machine, decrypt, set_speed,
halt — all unchanged.
- Pipeline gains spawn_named(name, depth, sink) so callers can
preserve identifiable thread names without the primitive baking
one in. Also adds Pipeline::try_send for the throttled
StatsRequest path that must not block the producer.
- Deleted src/disc/sweep_pipeline.rs entirely. WorkItem,
ProgressSnapshot, ConsumerSummary moved into disc/sweep.rs as
module-private types. WorkItem::Finish dropped — dropping the
channel is the end-of-stream signal Pipeline already uses.
Behaviour-preserving: the sweep algorithm, mapfile invariants,
back-pressure via channel depth (DEFAULT_PIPELINE_DEPTH = 4) all
match the 0.17.13 implementation. New synthetic regression test
(sweep_pipeline_full_good_100_batches) exercises ~100 batches of
clean reads end-to-end through the new Pipeline path and verifies
bytes_good and ISO file size.
See (internal)/memory/0_18_redesign.md.
Patch was strictly serial (per-sector recovery: read → seek+write
→ mapfile.record → next). Lifting the write+record onto a consumer
thread lets the drive issue the next per-sector retry while the
previous block's recovered bytes are being committed — small but
real win on damaged discs with many bad sectors, and uniform with
sweep's threading model.
- New PatchSink: Sink<PatchItem> impl in src/disc/patch.rs. Owns
WritebackFile + Mapfile. apply() seeks+writes recovered bytes
and records mapfile state per item; close() runs sync_all and
mapfile.flush.
- Channel depth: WRITE_THROUGH_DEPTH (1). Patch wants minimum
buffering — back-pressure should kick in immediately so the
drive's per-sector retry budget isn't ahead of the writer.
- Disc::patch: keeps every existing recovery decision on the
producer (reverse walk, damage-window skip, NOT_READY pauses,
bridge-degradation handling, wedge exit, range watchdog).
WritebackFile ownership moves to the sink.
Behaviour-preserving: per-sector single-shot read budget unchanged
(BU40N+Initio bridge wedge concern still respected); recovery
algorithm bit-identical.
See (internal)/memory/0_18_redesign.md.
Single contributor: MattJackson.
The type's job is the bounded-cache writeback pipeline (sync_file_range
+ posix_fadvise(DONTNEED)) — not generic writing. The 0.17 name was
ambiguous; reading `Writer::new(file)` gave no hint about what was
special. New name makes the role obvious at every call site.
Adds `WritebackFile::create(path)` and `WritebackFile::open(path)`
constructors so callers don't have to assemble a `File` first.
No alias kept; this is a clean 0.18 rename. See
(internal)/memory/0_18_redesign.md.
Single contributor: MattJackson.
The bounded-cache writeback wrapper (crate::io::Writer) was added in
0.17.10 and wired into Disc::sweep in 0.17.11, but the other two
paths in the crate that write large amounts of data sequentially —
Disc::patch and the MKV/M2TS mux — were still operating on raw
std::fs::File. That meant the dirty-page burst pathology the wrapper
exists to prevent could still bite on slow / network-attached staging
during recovery and mux phases.
This release plugs those gaps:
- Disc::patch (disc/mod.rs:1981) now wraps the reopened ISO in
Writer before any seek / write. sync_all on Writer cleanly drains
the in-flight chunk before the existing fsync.
- mux/resolve.rs MKV and M2TS branches wrap the output File in
Writer underneath BufWriter. UHD MKV mux routinely produces 70+ GB
of sequential output; the page cache no longer absorbs that as a
single hot blast on slow targets.
Mapfile, log, settings, history, and stream-pipeline byte buffers
remain unchanged: those are either small one-shot writes (where
the wrapper has zero benefit and adds a stream_position syscall) or
already use bounded persistence (mapfile time-batched in 0.17.12).
The principle: any path that writes substantial sequential data to
a single file uses Writer; trivial writes don't.
Pre-0.17.12 every Mapfile::record() persisted the full mapfile via
tempfile-create + write + atomic-rename. On local LVM that's
microseconds; on NFS each rename is multiple RPCs through the
unraid user-share fuse layer, dragging a Black Mass UHD rip from
~11 MB/s on local to ~1.5 MB/s on NFS — the mapfile path alone burned
multiple seconds of wall time per real-world second of work.
Mapfile now batches the rename to once per second:
- record() always updates in-memory state and stats; only fires
write_to_disk when last_flushed.elapsed() >= FLUSH_INTERVAL (1 s).
- New flush() API forces a persist; called by sweep_pipeline's
consumer at end-of-sweep and by Disc::patch at end-of-patch,
after the file's sync_all.
- Drop impl best-effort flushes so an early-return / unwind doesn't
silently lose pending state.
Crash-safety changes from "lose at most one block" to "lose at most
1 s of recorded progress" — the ISO file's payload bytes are unaffected;
only the mapfile's authority over which sectors are already-good is at
risk, and a resume re-reads anything Pass 1 had already covered.
Measured on the BU40N test bed against Black Mass UHD inner zone:
- NFS staging: 1.5 MB/s → 16.48 MB/s (10.9× recovery)
- Local LVM staging: 11.09 MB/s → 11.83 MB/s (+6.7 % bonus)
Internal round_trip_load test now flushes before reading back from
disk. External patch / copy tests are unaffected: patch and
sweep_pipeline flush at completion before returning.
Pre-0.17.11 sweep ran strictly serialised: SCSI read → decrypt → seek
+ write → mapfile.record → next read. Drive idled for the post-read
work; throughput capped at the sum of both costs. On a healthy disc
that's ~7-12 ms read + ~5-15 ms write/record per 64 KB batch, limiting
sustained throughput to ~10-12 MB/s on the test bed (BU40N + UHD inner
zone), well below the ~14-16 MB/s drive ceiling.
Decouples them: producer thread (caller's) owns SectorReader +
read_error state + decrypt + set_speed + halt; consumer thread (one
spawn) owns Writer + Mapfile, receives WorkItem messages, applies
file write + mapfile record. Bounded mpsc::sync_channel(4) gives
natural back-pressure. While the consumer writes batch N, the
producer is already reading batch N+1 — steady-state throughput is
now bound by the slower of the two pipelines (drive on healthy
discs), not their sum.
Side effects:
- Bisect path now decrypts. Pre-0.17.11 the bisect inner loop wrote
raw cyphertext for single-sector recoveries on encrypted discs —
quiet correctness bug exercised only by batch-fail-then-
bisect-succeed on encrypted media. New producer-side decrypt
covers main + bisect success paths uniformly.
- All read_ctx state stays single-threaded on producer (damage
window, jump multiplier, etc.). No locking added.
- Mapfile remains single-writer on consumer. No locking.
- Halt latency: producer breaks loop, sends Finish, consumer drains
≤4 in-flight items + sync_all. ~1 batch (~12 ms) typical.
- BU40N + Initio bridge wedge concern unchanged: still single SCSI
command in flight, error-path timing identical, no new retries.
New module: src/disc/sweep_pipeline.rs (WorkItem, ProgressSnapshot,
ConsumerInputs, spawn_consumer, consumer_loop, helpers). Public API
unchanged — Disc::copy / CopyOptions / CopyResult identical.
Patch (Pass N) is NOT changed; it's bound by drive recovery time, not
the read/write serialisation.
Pass 1 sweep speed on a healthy disc previously dipped from ~15 MB/s
to ~1 MB/s every ~30 s on a host with default Linux dirty-page
settings. Empirical cause: the kernel's vm.dirty_ratio (~20% of RAM)
lets hundreds of MB of dirty pages accumulate, then bursts a flush at
99% disk utilisation that blocks app writes for ~1 s. Confirmed on
the BU40N test bed — dirty pages grew 112 → 563 MB between bursts;
lowering vm.dirty_bytes to 64 MB at the host sysctl level eliminated
the dips. Shipping the equivalent inside libfreemkv so users do not
need to tune the host kernel.
- New crate::io::Writer: drop-in File wrapper (impl Write + Seek).
Wraps a per-platform WritebackPipeline that on Linux schedules
sync_file_range(WRITE) + lagging sync_file_range(WAIT_AFTER) +
posix_fadvise(DONTNEED) in 32 MB chunks, bounding dirty cache at
~64 MB. macOS and Windows ship a no-op stub.
- Disc::sweep wraps its output File in Writer. Loop body unchanged.
- Module is purpose-built so any large sequential output (patch,
mux) can adopt the same wrapper as a one-line change later.
Direct-SATA BU40N + Dune Part Two UHD live testing exposed that the
v0.17.3 single-shot SCSI READ path matched 0/22 of the small bad-
sector LBAs that dd if=/dev/sr0 recovers on the same drive. This
release closes that gap and fixes adjacent bugs silently capping
recovery.
- /dev/sr0 pread fallback in Drive::read (Linux only): on SCSI READ
Err, fall back to posix_fadvise(DONTNEED) + pread() against the
corresponding block device. Kernel sr_mod runs ~5 internal retries
with no per-attempt mid-layer escalation overhead — the mechanism
behind dd's recovery advantage. End-to-end byte verification
confirms the fallback path returns real disc data.
- Disc::patch per-range watchdog fix: MAX_RANGE_SECS was breaking
'outer (one slow range killed the entire patch). Now skips to the
next range. Pre-fix patch died after 4 sectors of range 1 of 47.
- Per-sector range budget: range_budget = sectors × 25 s, capped at
1800 s. Replaces the flat 180 s/range that was unfair to medium
ranges and pointlessly generous to single-sector ones.
- consecutive_failures resets per range. The wedge-exit detector is
for stuck-on-one-range, not many-small-ranges-with-one-fail-each.
- Reverted inline 5× retry experiment (was hurting: each retry paid
kernel SCSI escalation overhead). Restored READ_RECOVERY_TIMEOUT_MS
to 60 s. The kernel-auto-retry pattern is now provided by sr0
fallback.
Empirical: pass 1 recovered 94.6 MB / 11 s of main title (33 sr0
saves). Pass 2 added 0.6 MB. Remaining ~233 MB on the test disc
appears physically unrecoverable on this hardware.
src/disc/mod.rs:
- Cache priming (3-sector lookback) before patch's single-sector reads.
Drive read-ahead pulls in adjacent pages so the target may already be
cached when we ask for it. Throwaway reads — failures here don't
update mapfile state.
- When patch hits skip-limit on a range, leave remaining sectors
NonTrimmed instead of marking Unreadable. We never tried to read those
sectors, so don't give them terminal status — drive state evolves
between passes (cache, mechanical settle), and a later pass may
succeed.
tests/pass_n_patch_fix.rs:
- New regression test for the decrypt key inversion bug at
src/disc/mod.rs:1938-1942. Asserts decrypt_sectors is invoked with
the correct key when opts.decrypt=true.
tests/pass_n_size_aware_skip.rs:
- rustfmt-only changes.
Cargo.toml: 0.17.0 -> 0.17.1.
New disc/read_error.rs as the single entry point all read failures flow
through. Handler classifies the error, updates the in-flight context
(damage window, retry budgets, jump multiplier), and returns a
ReadAction the caller dispatches on. Pass 1 (sweep) refactored to use
it; ~340 lines of nested if/else collapsed into ~120 lines of action
dispatch. Adding a new error class = one match arm. Logging is in one
place. Bisect inner failures don't poison the damage window. Jump
multiplier capped at 64 (max 1 GB jump for batch=32 — observed prior
unbounded behavior produce a single 56 GB jump on a wedged drive).
Pass N (patch) damage_skip is now size-aware: each skip is capped at
range_remaining/4 rather than the absolute MB-scale escalation. The
old logic could leap over a 100-sector bad range that hides a 50-sector
good middle; size-aware convergence finds the good middles instead.
Tests in tests/pass_n_size_aware_skip.rs exercise the size-aware skip
against synthetic patterns (25-bad/50-good/25-bad and three good
middles in a row) and prove ≥98% of good middles are recovered.
Existing test test_disc_copy_marks_failed_ecc_blocks_as_nontrimmed
updated to reflect that MEDIUM_ERROR now triggers single-sector
bisect (which the BlockSizeFailingReader succeeds at).
- Fix unwrap in disc/mod.rs sweep() hot path using pattern matching
- Patch pass excludes Unreadable sectors from work list
- Expose bytes_bad_in_title for accurate UI reporting
- All 256 tests pass, cargo clippy clean with -D warnings
- DAMAGE_WINDOW 50→16, DAMAGE_THRESHOLD_PCT 25→12: triggers on 2nd scattered failure
- Previous 50/25% was too diluted by good reads between sparse failures
- copy() dispatch checks mapfile total_size == disc capacity_bytes (covers_disc)
- NonTried regions → sweep with resume=true (preserves mapfile)
- Only NonTrimmed/NonScraped/Unreadable → patch
- sweep_internal takes resume param: true when dispatching from existing mapfile
- Verified: Pass 1 from 30-100% completes in ~20 min with correct jumps through 3 damage zones
- CopyOptions: replace resume/skip_on_error/batch_sectors with single multipass bool
- Disc::copy() auto-detects pass from mapfile state: no mapfile or NonTried → sweep, only NonTrimmed/Unreadable → patch
- Fix bug where mapfile with NonTried regions incorrectly dispatched to patch mode
- SectorReader::set_speed() default method, Drive impl sends SET CD SPEED
- On damage zone entry: set_speed(0x0000) for better error recovery
- On damage zone exit (50 consecutive good): set_speed(0xFFFF) to restore max speed
- Disc::mapfile_for() returns /tmp/<name>.mapfile for null:// output
- patch_internal/sweep_internal as private helpers, CopyResult gains recovered_this_pass
- Adaptive probe algorithm in Disc::copy skip_on_error mode: after 4
consecutive errors, probe 1 sector at 256x batch (8 MB) ahead. If
good, zero-fill gap, mark NonTrimmed, jump. Clears bad zones in
seconds instead of hours.
- NOT_READY sense key (0x02) now retries up to 3x with 3s pause before
marking NonTrimmed. BU40N returns NOT READY for bad sectors, not
MEDIUM ERROR.
- PassProgress struct gains bytes_bad_total field for consumer-side
bad/retryable byte counts.
- Mapfile header version string fix: no longer duplicates 'libfreemkv v'
prefix on each write.
- Structured sense_key/asc/ascq logging in copy error path.
macOS SCSI transport rewritten from hybrid MMC+pread to single-path
raw CDB dispatch through SCSITaskDeviceInterface. All CDBs (INQUIRY,
READ, REPORT KEY, etc.) now go through ExecuteTaskSync — 1:1 with
the Linux SG_IO backend.
Key changes:
- New macos_shim.c: diskutil unmount → find IOBDServices →
ObtainExclusiveAccess → raw CDB dispatch. Eliminates Rust-side
IOKit COM vtable complexity.
- build.rs compiles macos_shim.c via cc into static lib
- macos.rs simplified to three FFI calls (open/close/execute)
- disc/mod.rs: graduated batch restore after errors, skip-ahead
through bad zones, configurable error pause
0.13.28 - when drive returns MEDIUM ERROR (bad sector), skip the sector
and continue instead of retrying or bailing. Write zero-fill, mark as
Unreadable for pass 2+ recovery.
Closes: (internal)#20260427
bytes_pending was an opaque aggregate of NonTried + NonTrimmed +
NonScraped. UIs that wanted a "will retry in Pass 2-N" bucket were
stuck showing the entire unread disc as Maybe at pct=0.
Adds two granular fields to MapStats:
bytes_nontried — Pass 1 hasn't read these yet
bytes_retryable — NonTrimmed + NonScraped, Pass 2-N will retry
bytes_pending stays for back-compat (= bytes_nontried + bytes_retryable).
Also picks up the cargo fmt --check lint that's been red on main CI
since v0.13.18 (rustfmt fold differences on a few long format-string
layouts; functional no-op).
Through the entire 0.13.x line, every CHECK CONDITION reply from the
drive (the standard way SCSI tells you why a sector failed) was being
collapsed into a synthetic status=0xFF, sense_key=0 transport-wedge
sentinel and the actual sense data was thrown away. Confirmed live on
the BU40N reading Dune 2 on 2026-04-27: drive returned host_status=0,
driver_status=8, status=2, exec_elapsed_ms=1416 on every bad sector
— a clean CHECK CONDITION carrying full sense data — and Disc::copy
was bailing on it as if the bridge had wedged.
Root cause: scsi/linux.rs's wedge check was
`host_status != 0 || driver_status != 0`
SG's DRIVER_SENSE bit (0x08) is set on every CHECK CONDITION reply
just to flag "sense buffer is populated" — it's not a transport
failure on its own. Pre-fix we conflated the two and silently lost
every drive-reported error reason. macOS and Windows backends had
the same shape: they extracted sense_key only, dropping ASC/ASCQ.
API restructure (clean separation):
Error::ScsiError {
opcode: u8,
status: u8, // 0xFF = synthetic transport-failure
sense: Option<ScsiSense>, // None ⇔ no sense delivered
}
pub struct ScsiSense { sense_key: u8, asc: u8, ascq: u8 }
impl ScsiSense {
pub fn is_marginal(&self) -> bool // keys 0/1/3/B
pub fn is_medium_error(&self) -> bool
pub fn is_hardware_error(&self) -> bool
pub fn is_unit_attention(&self) -> bool
pub fn is_data_protect(&self) -> bool
pub fn is_not_ready(&self) -> bool
pub fn is_illegal_request(&self) -> bool
pub fn is_aborted_command(&self) -> bool
}
impl Error {
pub fn scsi_sense(&self) -> Option<&ScsiSense>
pub fn is_scsi_transport_failure(&self) -> bool
pub fn is_marginal_read(&self) -> bool
}
SCSI protocol constants (SCSI_STATUS_*, SENSE_KEY_*) moved from
error.rs to scsi/mod.rs where they belong alongside SCSI_INQUIRY,
SCSI_READ_10, etc. parse_sense replaces parse_sense_key (returns the
full triple, not just the key); inline tests now exercise ASC/ASCQ
extraction at the right offsets for both descriptor (0x72/0x73) and
fixed (0x70/0x71) sense formats.
Disc::copy + Disc::patch sense-aware dispatch:
- marginal sense (MEDIUM ERROR / ABORTED COMMAND / RECOVERED ERROR
/ NO SENSE) → engage hysteresis (Block→Single, bpt=1)
- non-marginal sense (HARDWARE / DATA PROTECT / UNIT ATTENTION /
NOT READY / ILLEGAL REQUEST / transport failure / kernel
IoError) → bail with full sense info preserved; caller (autorip)
surfaces "physical replug" / "drive failing" / "media changed"
Pre-fix: every CHECK CONDITION → 0xFF synthetic → Disc::copy bailed
→ bytes_good froze at the bad zone. The hysteresis from v0.13.22
was correct but never got to run. This release unblocks it.
Disc::patch's wedged_threshold (50 consecutive failures) stays as
defense-in-depth for chains of marginal failures; a single
non-marginal sense now short-circuits it.
New phase=bail trace event records the bail reason with the sense
triple. phase=transport_err remains for genuine bridge wedges /
kernel timeouts; phase=scsi_err carries the parsed sense_key, asc,
ascq for drive-reported errors.
All 350 tests pass. Clippy clean across all targets.
The v0.13.21 bisect-on-fail recovery was correct (100% of recoverable
sectors picked up) but slow on dense damage clusters. Live test on
Dune 2 v0.13.21 burned ~30 s per damaged 60-block — paying a ~5 s
kernel ABORT/timeout at every level of a log₂(60) ≈ 6 deep DFS, on
the failing branch each time.
Replaced with a two-state hysteresis machine in Disc::copy:
Block(batch):
read(batch) ok → write, advance, stay Block
read(batch) fail → switch to Single, retry SAME range at bpt=1
Single:
read(1) ok → write, consecutive_good++
if consecutive_good >= BPT1_EXIT_THRESHOLD:
switch to Block, reset counter
read(1) fail → mark NonTrimmed, consecutive_good = 0
BPT1_EXIT_THRESHOLD = 10_000 sectors (= 20 MB clean run). Calibrated
from the 2026-04-26 BU40N empirical probe data; tunable.
Per-block math on a damaged 60-block with 1 truly bad sector:
Bisect (v0.13.21): ~30 s (5 s × 6 levels)
Hysteresis (v0.13.22): ~10 s (5 s bpt=batch fail
+ 59 × 1 ms good
+ 1 × 5 s bad)
Inside a damaged cluster spanning many 60-blocks the win compounds:
hysteresis pays the bpt=batch fail cost ONCE on entry, then stays at
bpt=1 across the cluster; bisection re-paid it every 60 sectors. For
Dune 2's ~1248-sector boundary cluster that's ~21 fewer 5-sec
kernel timeouts ≈ 100 s saved per pass.
Telemetry: new phase=mode_change trace event with from, to, lba, and
consecutive_good. Replaces v0.13.21's phase=bisect. Worklist DFS is
gone — single iterative for s in 0..count on the failure path.
Test rename, same fixture and same 100% recovery expectation:
test_disc_copy_bisect_recovers_via_single_sector_reads
→ test_disc_copy_hysteresis_recovers_via_single_sector_reads
Also adds DamageSeverity (Clean / Cosmetic / Moderate / Serious) +
classify_damage(bad_sectors, lost_ms), re-exported from libfreemkv,
so applications can render structured severity instead of formatting
their own from raw counters.
MattJackson