Commit Graph
5 Commits
Author SHA1 Message Date
Jaehoon KimandClaude Fable 5 c17aebeecf fix(filer.backup): prevent silent backup data loss on transient not-found (#10295)
* fix(filer.backup): stop silently dropping events on transient not-found

Under a write burst, filer.backup could consume a metadata event (advancing
the persisted offset) without replicating the file, with no error logged:

1. filersink CreateEntry/UpdateEntry swallowed replicateChunks errors
   (glog.Warningf + return nil), so the offset advanced past entries that
   were never written.
2. The manifest-chunk branch of replicateChunks resolved via LookupFileId
   with no retry, unlike the data-chunk branch — transient lookup races
   dropped exactly the large manifest-backed files while small
   inline-content siblings landed.
3. isIgnorable404 matched "LookupFileId" / "volume id ... not found",
   misclassifying those races as genuine source 404s at the backup layer.

Fix: on a replicateChunks failure the filer sink now skips only when the
live source has moved past the replayed version (deleted or strictly-newer
mtime) — lossless, a later event carries the current content — and
propagates otherwise so the event is retried. The manifest resolve retries
transient errors like the data-chunk path. isIgnorable404 is narrowed to
genuine 404s; non-filer sinks and the initial-snapshot walk, which relied
on the broad match as their only lossless-skip valve, now make the same
live-source decision (filersink.SourceSupersedes) instead of retrying
forever on a permanently gone volume.

Tests cover propagation of unconfirmed lookup failures, the narrowed 404
classification, and the supersession guards.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(filer.backup): derive supersession path with directory fallback

eventSourceSuperseded built the source path from NewParentPath alone.
Legacy metadata events (persisted by older filers) carry an empty
NewParentPath, so the probe looked up "/<name>", read the miss as
"source gone", and skipped a live file on a transient lookup error —
the silent drop this change is meant to eliminate.

Derive the path via MetadataEventTargetFullPath (the same directory
fallback genProcessFunction uses) and cover both event shapes with
TestEventSupersessionProbe_PathDerivation.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(filersink): retry manifest resolve only for transient errors, bounded when unverifiable

The manifest-resolve retry stopped only when hasSourceNewerVersion proved
the source moved past the replayed version, which wedged the sink in two
cases: incremental sinks use dated target keys that cannot map back to a
source path (supersession never provable), and permanent resolve errors
(corrupt manifest data, bad file ids) fail forever while the source entry
stays live.

Gate the retry instead: keep retrying only transient errors (volume-lookup
races, network interruptions), stop after a few attempts when supersession
cannot be checked, and propagate everything else immediately so the
configured metadata error policy applies (-disableErrorRetry included).
Propagation is lossless: filer.backup's fallback decides with the event's
real source key, and both filer.backup and filer.sync re-deliver the event
(RetryForeverOnError) without advancing the offset.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(filer.backup): make error classifiers nil-safe

isIgnorable404, isSourceLookupError, and isTransientResolveError called
err.Error() without a nil guard. All current call sites pass a non-nil
error, but the guard is free and matches isRetryableNetworkError.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
2026-07-10 01:47:46 -07:00
Jaehoon KimandChris Lu 202517c02a fix(filer.backup): skip replay events whose source chunk was superseded or deleted (#9886)
* fix(filer.backup): skip replay events whose chunk no longer exists on the source

"Source" is the filer we replicate FROM (e.g. green in a green->blue backup).

Replaying the metadata log from a checkpoint can hit an event whose chunk was
since overwritten/deleted and garbage-collected on the source volume. Fetching
it returns 0 bytes (a permanent size mismatch), which the sink propagated to the
subscription — so the same offset retried forever and replication stalled.

Skip the event only when proven stale; otherwise keep refusing so genuine loss
of a live file still halts loudly:

- onCorruptChunk centralizes the three errChunkSizeMismatch sites.
- getEntryMtimeNs compares mtime at nanosecond precision so same-second rewrites
  (git's config.lock dance) are ordered correctly.
- sourceSupersedes re-reads the entry's current state on the source: gone
  (ErrNotFound) or a strictly-newer mtime than the replayed version -> skip;
  any other lookup error keeps the entry.

Skipping is lossless: events are full-entry snapshots, so a later event
re-carries the current chunks and a delete event reconciles a removed file.

* test(filer.backup): cover the superseded-chunk skip decision

- TestSourceSupersedes: not-found (sentinel / wrapped / gRPC string) and nil
  entry -> skip; network error -> keep; source newer -> skip; same/older -> keep.
- TestGetEntryMtimeNs: nanosecond precision, same-second ordering, nil safety.
- TestOnCorruptChunkRefusesWhenSupersessionUnconfirmed: never skip silently when
  supersession cannot be confirmed.

* fix(filer.backup): don't infer supersession for incremental sinks

In incremental mode the sink key carries a date prefix
(sinkDir/YYYY-MM-DD/relPath) that cannot be reversed to a real source path, so a
source lookup would always be ErrNotFound and wrongly classify a live entry as
deleted — skipping it. Make targetPathToSourcePath report "unmappable" in
incremental mode; hasSourceNewerVersion already declines to skip when the source
path cannot be mapped.

Found in code review. Non-incremental sinks (filer.backup green->blue) are
unaffected.

* refactor(filer.backup): name the mtime param sourceMtimeNs; note ns overflow bound

- Rename the threaded sourceMtime parameter to sourceMtimeNs across the internal
  replicate/fetch helpers so the unit is explicit (it only feeds
  hasSourceNewerVersion, which compares in nanoseconds).
- Document that getEntryMtimeNs's int64 ns arithmetic is safe until ~year 2262.

No behavior change.

* fix(filer.backup): order same-second versions in the CreateEntry skip and update gates

The CreateEntry already-replicated short-circuit and chooseUpdateAction
still compared second-grained mtime, so a newer version written within
the same second could be skipped as already-replicated or overwritten by
an older same-second replay. Route both through getEntryMtimeNs, matching
the precision the chunk-replication path already uses.

* test(filer.backup): cover same-second update-action ordering

* docs(filer.backup): trim verbose comments to terse why

* fix(filer.backup): check supersession against the rename's new path

For a rename the filer sink updates in place (the delete+create branch is
skipped for sink name "filer"), so the corrupt-chunk supersession check
queried the pre-rename key. Its source-side ErrNotFound was read as
"superseded", silently advancing the checkpoint without applying the rename.
Map the incoming entry's new path (newParentPath/newEntry.Name) for both
update branches.

* fix(filer.backup): detect a deleted source even when the replayed mtime is epoch

hasSourceNewerVersion returned early when sourceMtimeNs <= 0, skipping the
source lookup, so a deleted entry with mtime 0 (a valid epoch timestamp) never
got the gone verdict and wedged on permanent retries. Always look up; gate only
the newer-mtime comparison on a valid replayed mtime.

---------

Co-authored-by: Chris Lu <chris.lu@gmail.com>
2026-06-09 08:53:29 -07:00
Chris Lu 2e3fabbf24 filer.sync: back off on transient upload errors (#9777)
A destination volume server that hits its idle deadline while reading a large upload body under load returns 400 "read tcp ...: i/o timeout". fetchAndWrite retried that on the flat ~1s RetryUntil backoff, hammering the already-overloaded destination. Route i/o timeout, connection reset, broken pipe and net.Error timeouts through the same escalating 10s-2min backoff already used for EOF so it can recover.
2026-06-01 12:18:17 -07:00
675020b342 fix(filer.sync): validate chunk size in FilerSink to prevent 0-byte propagation (#9701)
* fix(filer.sync): validate chunk size in FilerSink to prevent 0-byte propagation

FilerSink.fetchAndWrite previously trusted the source response and the
upload result blindly: a 200 OK / Content-Length: 0 reply from a broken
source volume was happily uploaded as a 0-byte needle to the destination,
and the destination filer metadata was then written with the source
chunk size. The result was permanent silent corruption -- ls shows the
file at its original size but reads fail with EIO.

Add two cheap defenses inside fetchAndWrite:

  1. After assembling fullData, compare its length against sourceChunk.Size.
  2. After a successful upload, compare uploadResult.Size against
     sourceChunk.Size.

Both checks wrap a new sentinel errChunkSizeMismatch that the retry
callback recognizes and refuses to retry -- needle.size=0 on disk is a
persistent state, not a transient network error, so the sync should stop
loudly on the affected entry instead of looping or, worse, silently
propagating it.

Tests:

  * TestValidateReplicatedChunkSize -- table-driven coverage of healthy,
    legitimately empty, zero-byte read, short read, and truncated upload
    cases.
  * TestFetchAndWriteRejectsZeroByteSource -- end-to-end: an httptest
    source that returns 200 OK with an empty body must cause fetchAndWrite
    to return errChunkSizeMismatch after exactly one source hit (fail
    fast, no retry storm).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* filer.sync: bubble size-mismatch past CreateEntry/UpdateEntry

Three follow-ups on the chunk-size validation:

- Use %w in replicateOneChunk so the errChunkSizeMismatch sentinel
  survives the wrap and reaches errors.Is callers up the stack.
- In FilerSink.CreateEntry/UpdateEntry, surface errChunkSizeMismatch
  instead of warning-and-nil. Other errors (deleted source chunk,
  transient network) keep the existing swallow so a hiccup doesn't
  stall the stream.
- Drop validateReplicatedUploadSize: uploadResult.Size is set
  client-side from the same len(fullData) we already validated
  pre-upload, so the second check can't fail.

Test: scope the RetryWaitTime override to the one test that needs it,
add a regression that locks in the errors.Is chain through
replicateChunks.

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: Chris Lu <chris.lu@gmail.com>
2026-05-26 20:47:53 -07:00
Chris Lu be0379f6fd Fix filer.sync retry on stale chunk (#8298)
* Fix filer.sync stale chunk uploads

* Tweak filersink stale logging
2026-02-10 19:06:35 -08:00