fix(lock): fence write commit on lock loss (backlog#899 Phase 2)
Phase 0+1 (#4388) made object write locks refreshable and marks the guard
lost when the heartbeat can no longer refresh a quorum, but does not act on
it. Under a partition a long write's lock can expire on an unreachable node
and be reclaimed, letting a third party re-acquire it; the original writer
keeps going and both commit -- a double write.
Expose the loss signal through NamespaceLockGuard::is_lock_lost() and
ObjectLockDiagGuard::is_lock_lost(), and fence the commit in put_object and
complete_multipart_upload: immediately before rename_data (the atomic commit
point), abort with a retryable NamespaceLockQuorumUnavailable (503) if the
lock was lost. In multipart the check precedes cleanup_multipart_path so a
lost lock leaves the upload intact and retryable. A write that already
reached rename_data Ok is durable and never aborted.
The loss criterion is unchanged (reacts to Phase 1's signal). Heal and the
long-GET read side are deferred follow-ups.
* feat(ecstore): add object lock diagnostics
Add configurable namespace lock diagnostics for object operations so production contention can be traced by operation, owner, and key.
Wrap object read/write lock acquisition in diagnostic guards across get, head, put, delete, copy, and multipart flows, and log slow acquisition and long hold durations behind new RUSTFS_OBJECT_LOCK_DIAG_* settings.
Verification:
- make pre-commit
* feat(obs): expose object lock diagnostics metrics
Add Prometheus metrics and Grafana panels for object namespace lock diagnostics, covering slow acquire counts, slow hold counts, acquire duration, hold duration, and the diagnostics-enabled state.
Adopt PR review feedback by keeping diagnostic guards alive through the guarded operation so long-hold warnings and metrics are emitted, reusing shared env helpers, and reducing default-path overhead when diagnostics are disabled.
Verification:
- cargo check -p rustfs-ecstore -p rustfs-io-metrics
- cargo test -p rustfs-ecstore store::object -- --nocapture
- make pre-commit
* perf(obs): reduce object lock diag overhead
Avoid repeated environment parsing on hot object-lock paths by caching the diagnostics-enabled flag, and stop allocating label strings for object lock metrics by recording static labels directly.
Strengthen io-metrics tests by using a local recorder and asserting that the expected object lock diagnostic counters, gauges, and histograms are emitted.
Verification:
- cargo check -p rustfs-ecstore -p rustfs-io-metrics
- cargo test -p rustfs-io-metrics -- --nocapture
- make pre-commit
Henry Guo