Add an io::fsync module with a per-OS split (posix/windows) mirroring the
writeback_file convention, replacing two duplicated dir-fsync copies:
- dir(): POSIX directory fsync; a no-op on Windows, where std cannot open
a directory as a File and the failed open logged a spurious warning on
every mapfile write.
- file_durable(): opens the target read+write before sync_all so the flush
succeeds on Windows, where FlushFileBuffers rejects a read-only handle
with ERROR_ACCESS_DENIED.
Point the mapfile writer at the shared dir() helper.
Library-wide review-and-fix pass: tightened AACS keydb/handshake/variant
handling and trailing-partial-unit policy, corrected MPLS mark offset and
added UDF allocation bounds, hardened the mux/codec framing and M2TS paths,
guarded SCSI READ CAPACITY short transfers and unified error mapping, added
overflow guards on untrusted disc input, and made prefetch shutdown
deterministic. Release profile now builds with thin LTO + single codegen unit.
Introduces the freemkv mux throughput highway: a three-stage thread
pipeline that replaces the inline single-thread read path for any
file-backed source (ISO and m2ts file URLs both route through it).
Thread A: read + decrypt (PrefetchedSectorSource / BytePrefetcher)
Thread B: M2TS demux (DemuxThread)
Thread C: codec parse (PipelinedPesStream, on caller thread)
Each handoff uses a bounded crossbeam channel with a recycled buffer
pool — no allocations or memcpys in the steady-state hot loop.
Component map:
* io/byte_prefetcher.rs (new) — std::io::Read producer thread with
recycled Vec<u8> pool. Pairs with PrefetchedSectorSource (sector
side) so demux_thread::spawn_zero_copy can wire either upstream.
* sector/prefetched.rs — recycled buffer pool added; into_channels()
peels off the rx/recycle_tx/shell triple for zero-copy demux.
* mux/demux_thread.rs (new) — owns the TsDemuxer/PsDemuxer, runs
feed() on its thread, ships Vec<PesPacket> batches.
* mux/pipelined_stream.rs (new) — the read-side Stream impl. Pulls
packets from the demux thread and runs codec parse on the caller.
* mux/resolve.rs — build_iso_pipeline (public) / build_m2ts_pipeline
(private) assemble the three stages; iso:// and m2ts:// both
return PipelinedPesStream.
* mux/m2ts.rs — collapsed to a write-only sink (Mode::Read deleted;
the read direction lives on the highway now).
* mux/codec/h264.rs — find_start_code uses memchr SIMD memmem::find.
* mux/codec/hevc.rs — tightened frame_data initial capacity.
* mux/ts.rs — boundary-packet handling avoids the per-batch 16 MiB
remainder copy; PesAssembler starts at 16 KiB to dodge the 64-page
first-touch fault tax that the previous 256 KiB pre-alloc paid on
every PES boundary.
* mux/disc.rs — gains DiscStream::new_pipeline + read_pipeline as
the legacy autorip ingress (drive + multipass paths still need
on_event / skip_errors before they migrate to the highway).
* io/file_sector_source/* — per-OS prefetch() syscall hook
(Linux readahead, macOS F_RDADVISE, Windows/other no-op).
* decrypt.rs — FREEMKV_DECRYPT_THREADS renamed to FREEMKV_THREADS;
pool sized to all cores by default.
Measured on rip1 testbed (Civil War UHD, 62 GiB ISO → null://):
60 → 322 MB/s warm cache (old new_pipeline path)
60 → 660 MB/s warm cache (highway path, this commit)
60 → 126 MB/s sustained disk-bound
The IsoSectorReader baseline reader was deleted in favour of
FileSectorSource so the freemkv CLI and autorip exercise the same
read path.
Introduces the SequentialSink / RandomAccessSink trait pair under
io::sink and an open_for_mkv dispatch helper that picks WritebackFile
on Linux+NFS and LocalFileSink everywhere else. LocalFileSink wraps
BufWriter<File> with a 4 MiB buffer and exposes a per-OS preallocate
path (fallocate on Linux, F_PREALLOCATE on macOS, no-op fallback).
Adds platform::fs_type::detect with a per-OS split (statfs on Linux /
macOS, UNC heuristic on Windows, Unknown elsewhere) so construction-
site dispatch has a single primitive to call.
Blanket impls cover the common shapes: any Write+Send is a
SequentialSink, and any SequentialSink+Seek is a RandomAccessSink.
WritebackFile satisfies the random-access trait via the blanket impl
without needing an explicit per-type impl. No callers wired yet — the
mux::resolve construction sites stay on WritebackFile pending Phase 3.
Tests: 5 new sink/preallocate tests + 3 fs_type tests (1 ignored,
needs a real NFS mount). cargo +1.86 fmt + clippy + tests all green.
Three changes targeting 0.20.9's "muxer never read-stalls on NFS read
latency" invariant:
A. FileSectorSource gets a 32 MiB internal read-ahead buffer
(READAHEAD_BUF_BYTES). Splits out from src/sector/file.rs into
src/io/file_sector_source/ with per-OS open hints (Linux
posix_fadvise(SEQUENTIAL), macOS fcntl(F_RDADVISE) with 64 MiB
cap, Windows TODO stub, BSD/illumos no-op). Backward seeks
rebuffer; partial reads at EOF return only the bytes that exist;
oversize-request bypass for count > BUF_SECTORS.
B. WritebackFile inline #[cfg(target_os = "linux")] blocks split
into per-OS files under src/io/writeback_file/. Linux unchanged
(fallocate KEEP_SIZE, fsync via bounded_syscall). macOS gets a
real F_PREALLOCATE + F_FULLFSYNC impl (was a "skipped (non-linux)"
debug log before). Windows is a stub (FlushFileBuffers via
std sync_all; TODO for SetFileValidData). BSDs/illumos fall back
to std sync_all.
C. New byte_channel module — byte-bounded producer/consumer wrapping
std sync_channel with Mutex/Condvar byte accounting. Sender blocks
when used_bytes + item.byte_size() > capacity. HasByteSize impl
for PesFrame. Default cap BYTE_CHANNEL_DEFAULT_CAPACITY = 64 MiB,
sized to absorb worst-case NFS read p99 (~2 s × UHD peak compressed
~15 MB/s). The mux call site lives in autorip (out of scope here);
this lands the primitive in libfreemkv for autorip to adopt.
Test counts: byte_channel +6, file_sector_source +5, sector::file
round-trip suite (3) preserved. passn_handler_ab.rs A/B fixture
(8 profiles) still green.
precommit.sh libfreemkv: fmt + clippy + test all green on Rust 1.86.
No version bump; no Cargo.lock changes; no forbidden-file edits
(disc/patch.rs, disc/read_error.rs, io/pipeline.rs,
tests/passn_handler_ab.rs).
Generalizes 0.20.5's hand-written wait_after_with_timeout into a
reusable primitive. After this change, every blocking syscall in the
recovery + mux paths is wrapped, so cooperative Halt has bounded
~250 ms latency reach even into kernel-owned thread states.
New module src/io/bounded.rs:
- BoundedError { Halted, Timeout, WorkerLost }
- bounded_syscall<F, R>(halt: Option<&Halt>, timeout, op) -> Result<R, BoundedError>
- Worker thread runs op; main thread recv_timeouts on a rendezvous
channel in 250 ms slices, polling halt between slices.
- Worker is intentionally leaked on timeout/halt — kernel reaps when
the syscall finally returns or at process exit. Calling thread is
NEVER trapped inside a kernel call.
- 6 unit tests cover the happy path + each error variant.
Refactored callsites:
- src/io/writeback/linux.rs::wait_after_with_timeout now delegates
to bounded_syscall. ~30 LOC of duplicated channel/thread plumbing
deleted. Same semantics, cleaner.
- src/io/writeback_file.rs::WritebackFile::sync_all now wraps the
final libc::fsync(fd) with bounded_syscall (60 s deadline). On
timeout: log error at target=mux and return Ok — kernel will flush
on close, best-effort but bounded. Covers FileSectorSink::finish,
PatchSink::close, SweepSink::close, and the mux MKV finalize path
(they all sync through WritebackFile).
What still hangs (deliberately not wrapped — too hot a path):
- File::write itself. Per-frame write on a wedged NFS could still
block; but back-pressure from a stuck consumer means the producer
notices within seconds, not minutes — different failure mode than
the WAIT_AFTER hang 0.20.5/0.20.6 fix.
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.
Generic bounded producer/consumer pipeline. The same shape applies to
sweep, patch, and mux today via three near-duplicate implementations
(or, in patch's and mux's case, no implementation at all). 0.18
collapses them onto one primitive. See
(internal)/memory/0_18_redesign.md for full context.
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.
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.
Matthew Jackson