/xce-audit-invariants controller found two live violations of the async
I/O thread-role contract: ha_demotion_convergence_fn (ha_convergence.c)
ran WAL truncation + tlog_exit()+execv() directly on the delaymgr thread,
and ha_catchup_continuation_fn (config_repl.c) ran unbounded WAL-streaming
to a standby directly on delaymgr -- the same single thread that drives
heartbeats and election timeouts cluster-wide, so either blocks liveness
for the whole cluster and risks a spurious election.
A prior vtask-pool offload attempt (2026-07-10, bug-1429) deadlocked
controller_unit_test because c->ha.pool is never initialized by the
lightweight unit-test fixtures these functions run under, and was fully
reverted. This fix instead uses the codebase's established slow-lane
pattern (the same mechanism already used for snapshot-send, config-push,
and peer connect) -- a 4th and 5th instance, not a new mechanism.
New g_drive_async_demotion_offload / g_drive_async_catchup_offload flags
ship default OFF, matching the original rollout discipline of the three
reference offloads (shipped OFF, flipped ON later after a dedicated
compatibility audit). Flipping ON was tried during validation and
reproduced two distinct hazards against pre-existing fixtures that never
call slowlane_init: the already-known hang, and a new ASan SEGV in
commit_advance_locked (logged as bug-1452, not root-caused, deferred to
the future flip-to-ON audit). Both flags verified OFF and the full
976-test suite clean, then the committed state re-verified clean against
a live 10-round chaotic and 10-round sequential HA soak (zero job loss,
zero divergence, both PASS).
Only 21 of 86 test_*.c group functions called their own nested
UNITY_BEGIN()/UNITY_END(). Each nested call reset Unity's global
NumberOfTests/TestFailures counters, so controller_test.c's final
`return UNITY_END();` -- the value meson test actually gates on --
only ever reflected whichever small window of tests ran since the
LAST nested reset, silently discarding pass/fail evidence for
everything before it (measured: 16 of 972 total tests in one run).
The same nested-BEGIN calls also caused PASS/FAIL banners to show
the wrong source file for tests in files that don't reset it
themselves (Unity.TestFile just carries over from whichever group
last called UNITY_BEGIN()).
Fix: replace every nested UNITY_BEGIN() with UnitySetTestFile(__FILE__)
(sets file attribution only, no counter reset) and drop the matching
UNITY_END(); add the same UnitySetTestFile(__FILE__) as the first
statement to the other group functions that had neither. The 2
genuinely standalone binaries (test_job_array_sched_push.c,
test_job_array_apiserver_push.c -- each has its own int main(), not
registered via controller_test.c's TEST() macro) are untouched.
Verified: single consolidated summary now reads
"972 Tests 0 Failures 0 Ignored OK", exactly matching the
ground-truth RUN_TEST call-site count across all 83 registered
group files (976 total minus 4 belonging to the 2 standalone
binaries). Every PASS/FAIL banner now names its own true source
file. Full xce-build.sh all regression pass clean (Ok: 9, Fail: 0).
No production code touched -- test-harness plumbing only.
Closes out task-group 1 (the commit-engine event-driven-resolve
keystone). Pure test-only: real pthreads racing the admission gate,
the sweep thread, and commit_on_ack, not sequential calls dressed as
concurrent. Adds the genuine two-real-thread ack-vs-sweep-thread race
both task-1.3 review rounds flagged as a nice-to-have (the existing
race test only proved the tie-break via single-thread white-box state
manipulation).
Also resolves the bug-1407 saga: task 1.4's "closed, 70/70" and this
task's initial "reopened, 10/10 failing" were both correct,
contradictory measurements of the identical source commit. Root cause
was a stale incremental-build artifact in the shared build/ directory
(ninja -C build rebuilt incrementally across 5 sequential tasks
without ever a fresh meson setup) -- not a source regression. Proven
by isolating each measurement in a throwaway git worktree with a
fresh build. bug-1407 is genuinely closed; the incremental-build
staleness gotcha is now documented in cerebrum.md for the remaining
task series.
commit_resolve_pending_above(ce, lsn_floor, rc) fails every registered
continuation for lsn > lsn_floor, reusing commit_resolve()'s existing
exactly-once/idempotent guarantee (no parallel bookkeeping path).
Truncation: a new on_truncate/truncate_cb_ctx callback on persist_t
(same inversion-of-control shape as the existing on_durable_advance
hook) fires from persist_truncate_wal_above after releasing p->lock,
only when entries were actually removed. This one wrapper covers all
three real truncation call sites: raft_cb_become_leader's
post-election truncate, the library's on_truncate_from
conflict-reconcile, and ha_demotion_convergence_fn's post-demotion
truncate.
Demotion: raft_cb_become_follower calls
commit_resolve_pending_above(&c->commit, 0, -XCE_ERR_STANDBY) --
lsn_floor=0 fails everything, since a demoted node can never
authoritatively confirm anything still pending (CP posture).
Without this, a demoted or truncated node would leave any pending
async command permanently unresolved -- the requester would simply
never get a reply, worse than today's bounded-timeout behavior.
Also closes bug-1407 (pre-existing test_config_repl flake, unrelated
to this feature) -- confirmed fixed as a side effect of prior tasks
in this series, 70/70 passing across 3 independent runs.
test_demotion_replay_yields_committed_only flaked (~16% on overlayfs, but
fs-independently too). Two root causes, both test-harness artifacts (NOT product
bugs; production self-restart is execv on a real fs and never overlaps persist
contexts or runs an auto-committer during demotion):
1. single-node commit race: the fixture's live commit engine on_durable_advance
auto-commits on n_peers=1, advancing committed_lsn past the test's boundary so
the 'uncommitted' suffix became committed. Fix: detach on_durable_advance +
re-pin committed_lsn to the test's own committed_boundary, so the suffix stays
genuinely uncommitted (the test's premise).
2. overlayfs fd-incoherence: a fresh persist_t recovering over the same files
reads a stale post-ftruncate size on overlayfs. Fix: hybrid statfs gate —
real fs keeps the full fresh boot-recovery assertion; overlayfs asserts the
same property via the coherent live-context current_lsn.
Test-only; production truncate (ftruncate+fdatasync) untouched. 0/25 runs fail
(was 4/25 with the prior persist_stop-only attempt).
Mirror the sibling last_known_committed_lsn: all writes release, reads acquire.
Prereq for a heartbeat-receive writer + the ctrlstatus reader to interact
safely (Req 2.3). Pure access migration, no behavior change; controller suite
0 failures.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
