2 Commits

Include renames

Author	SHA1	Message	Date
4 people	f31a026b2a	master,filer: fix lock ring poisoning after leader change (#11453) ... * cluster: never broadcast an empty lock ring An empty member list is never a usable ring state, but a delayed RemoveServer on a former leader can fire after the new leader already broadcast the recovered ring. That late broadcast carries a newer wall-clock version, so clients accept the empty ring and permanently reject the good one. Skip the broadcast entirely when the member list is empty, keeping the last non-empty snapshot for reconnecting clients. * cluster: periodically rebroadcast the lock ring Ring updates are purely event-driven, so one lost or poisoned update is permanent until the next membership change — with a single filer that may never come. Re-arm a per-group timer after every broadcast so the current leader keeps re-sending the ring; clients reject nothing newer than their last accepted version, so a re-sent snapshot always heals a stale view. * filer,s3api: reset the lock ring on master change Ring versions are per-master monotonic — each master stamps wall-clock nanoseconds — so a late high-version update accepted from a former leader makes the new leader's snapshot look stale forever. Detect a leader change across the reconnect gap (currentMaster is cleared between attempts, so remember the last served master) and reset the ring to bootstrap state so the new leader's view always applies. * cluster: fail lock acquisition when no lock server exists retryUntilLocked loops forever, so a filer reporting an empty lock ring wedges every append write indefinitely. Bound only the "no lock server found" case — ordinary contention is still waited out since the holder releases eventually. The constructors now return nil on failure: the filer append path and S3 object writes fail fast, while mounts degrade to their existing lockless mode. * cluster: reset only the ring version on master change Ring versions are per-master monotonic, so a version gate reset is all a leader change needs. Clearing the whole ring made every filer its own write owner until the next update and dropped the prior-owner window for keys the new leader remaps; the last ring now keeps routing until the new leader's snapshot transitions off it. * cluster: skip redundant ring installs and defer rebroadcasts An unchanged member list now only bumps the accepted version instead of installing a snapshot: periodic rebroadcasts no longer fire the topology-change callback or restart the prior-owner window. And a rebroadcast that lands inside a membership stabilization window yields to the pending timer rather than publishing an intermediate ring. * cluster,mount: bound lock unavailability, fail ops that cannot lock Only 'lock already owned' contention retries without bound now; every other failure — no lock server, or a dead ring member refusing connections — shares the same unavailability budget, so a ring naming departed filers can no longer hang a lock forever. Mount open-write, create, and rename fail with EAGAIN when the required lock cannot be acquired instead of proceeding without cross-mount serialization. * cluster: check pending stabilization inside the broadcast critical section rebroadcast released the mutex between the pending-timer check and nextBroadcastUpdate, so a membership change arriving in the gap could arm a stabilization timer while the rebroadcast emitted an intermediate ring. Generated with [Devin](https://devin.ai) Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com> * mount: acquire path locks before mutating create/rename state Create took the DLM lock only after the filer create, so a lock failure returned EAGAIN with an eagerly persisted file left behind. Rename marked source handles renamed before acquiring locks, so a failed acquisition left them suppressing old-path flushes for a rename that never happened. Both now take the locks first; the create's lock is released again if the entry race loses to another creator and AcquireHandle takes over. Generated with [Devin](https://devin.ai) Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com> * mount: keep the old-path lock when rename lock migration fails The migration stopped the handle's lock before acquiring the replacement, so a nil result left the handle writing with no lock at all. Acquiring the new-path lock first means failure keeps the existing lock instead of reporting success with serialization dropped. Generated with [Devin](https://devin.ai) Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com> * mount: skip new-path rename lock when a handle already holds it A target file open for write on this mount already carries a lock on newPath; the lock manager does not grant a second lock to the same owner, so the rename would wait on itself until the handle closed. Also avoid locking twice when old and new paths coincide. Generated with [Devin](https://devin.ai) Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com> * mount: hand the rename's target lock to the migrating handle The rename holds a lock on newPath for its duration, so the response migration's fresh acquisition waited on that same lock until the handle released — under fhLockTable, blocking the handle's own close. Adopt the rename's lock directly; nested move responses still acquire their own. Generated with [Devin](https://devin.ai) Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com> * mount: move the replaced target's lock to the renamed handle When the target path was already locked by an open handle on this mount, the migrated source handle kept only its stale old-path lock — the target's close would then release the last lock on the new path while the renamed handle was still open. Adopt the replaced handle's lock instead. Generated with [Devin](https://devin.ai) Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com> * mount: stop the handle lock inside the fh lock on release ReleaseHandle stopped fh.dlmLock before taking the fhLockTable slot, so a rename migration holding that slot could still observe and adopt a lock that was already stopping. Stopping under the fh lock makes the transfer serialize against the release. Generated with [Devin](https://devin.ai) Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com> * mount: claim the replaced target's lock for the renamed handle When the target path is already locked by an open handle on this mount, adopting it at migration time keeps the renamed path protected after that handle closes, without waiting on a lock this mount already holds. If the handle was released mid-migration the claimed lock is stopped, and a fresh acquire covers the case where it was already gone. Generated with [Devin](https://devin.ai) Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com> * mount: claim the target handle's lock before the rename runs Skipping the new-path lock when a handle already holds it let that handle's close release the lock mid-rename, leaving the path unguarded until the response migrated it. Take over the lock at check time and hold it for the rename's duration: the response adopts it for the migrating handle, or it returns to the target handle / is released on failure. The target handle lookup also falls back to the entry's stored inode for a forgotten path mapping. Generated with [Devin](https://devin.ai) Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com> * mount: read handle locks only under the fh lock during rename The loose dlmLock reads raced ReleaseHandle, which now mutates the lock inside the handle lock; check and claim it under the same hold. Generated with [Devin](https://devin.ai) Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com> --------- Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>	2026-09-26 11:57:00 +08:00
3 people	75a6a34528	dlm: resilient distributed locks via consistent hashing + backup replication (#8860) ... * dlm: replace modulo hashing with consistent hash ring Introduce HashRing with virtual nodes (CRC32-based consistent hashing) to replace the modulo-based hashKeyToServer. When a filer node is removed, only keys that hashed to that node are remapped to the next server on the ring, leaving all other mappings stable. This is the foundation for backup replication — the successor on the ring is always the natural takeover node. * dlm: add Generation and IsBackup fields to Lock Lock now carries IsBackup (whether this node holds the lock as a backup replica) and Generation (a monotonic fencing token that increments on each fresh acquisition, stays the same on renewal). Add helper methods: AllLocks, PromoteLock, DemoteLock, InsertBackupLock, RemoveLock, GetLock. * dlm: add ReplicateLock RPC and generation/is_backup proto fields Add generation field to LockResponse for fencing tokens. Add generation and is_backup fields to Lock message. Add ReplicateLock RPC for primary-to-backup lock replication. Add ReplicateLockRequest/ReplicateLockResponse messages. * dlm: add async backup replication to DistributedLockManager Route lock/unlock via consistent hash ring's GetPrimaryAndBackup(). After a successful lock or unlock on the primary, asynchronously replicate the operation to the backup server via ReplicateFunc callback. Single-server deployments skip replication. * dlm: add ReplicateLock handler and backup-aware topology changes Add ReplicateLock gRPC handler for primary-to-backup replication. Revise OnDlmChangeSnapshot to handle three cases on topology change: - Promote backup locks when this node becomes primary - Demote primary locks when this node becomes backup - Transfer locks when this node is neither primary nor backup Wire up SetupDlmReplication during filer server initialization. * dlm: expose generation fencing token in lock client LiveLock now captures the generation from LockResponse and exposes it via Generation() method. Consumers can use this as a fencing token to detect stale lock holders. * dlm: update empty folder cleaner to use consistent hash ring Replace local modulo-based hashKeyToServer with LockRing.GetPrimary() which uses the shared consistent hash ring for folder ownership. * dlm: add unit tests for consistent hash ring Test basic operations, consistency on server removal (only keys from removed server move), backup-is-successor property (backup becomes new primary when primary is removed), and key distribution balance. * dlm: add integration tests for lock replication failure scenarios Test cases: - Primary crash with backup promotion (backup has valid token) - Backup crash with primary continuing - Both primary and backup crash (lock lost, re-acquirable) - Rolling restart across all nodes - Generation fencing token increments on new acquisition - Replication failure (primary still works independently) - Unlock replicates deletion to backup - Lock survives server addition (topology change) - Consistent hashing minimal disruption (only removed server's keys move) * dlm: address PR review findings 1. Causal replication ordering: Add per-lock sequence number (Seq) that increments on every mutation. Backup rejects incoming mutations with seq <= current seq, preventing stale async replications from overwriting newer state. Unlock replication also carries seq and is rejected if stale. 2. Demote-after-handoff: OnDlmChangeSnapshot now transfers the lock to the new primary first and only demotes to backup after a successful TransferLocks RPC. If the transfer fails, the lock stays as primary on this node. 3. SetSnapshot candidateServers leak: Replace the candidateServers map entirely instead of appending, so removed servers don't linger. 4. TransferLocks preserves Generation and Seq: InsertLock now accepts generation and seq parameters. After accepting a transferred lock, the receiving node re-replicates to its backup. 5. Rolling restart test: Add re-replication step after promotion and assert survivedCount > 0. Add TestDLM_StaleReplicationRejected. 6. Mixed-version upgrade note: Add comment on HashRing documenting that all filer nodes must be upgraded together. * dlm: serve renewals locally during transfer window on node join When a new node joins and steals hash ranges from surviving nodes, there's a window between ring update and lock transfer where the client gets redirected to a node that doesn't have the lock yet. Fix: if the ring says primary != self but we still hold the lock locally (non-backup, matching token), serve the renewal/unlock here rather than redirecting. The lock will be transferred by OnDlmChangeSnapshot, and subsequent requests will go to the new primary once the transfer completes. Add tests: - TestDLM_NodeDropAndJoin_OwnershipDisruption: measures disruption when a node drops and a new one joins (14/100 surviving-node locks disrupted, all handled by transfer logic) - TestDLM_RenewalDuringTransferWindow: verifies renewal succeeds on old primary during the transfer window * dlm: master-managed lock ring with stabilization batching The master now owns the lock ring membership. Instead of filers independently reacting to individual ClusterNodeUpdate add/remove events, the master: 1. Tracks filer membership in LockRingManager 2. Batches rapid changes with a 1-second stabilization timer (e.g., a node drop + join within 1 second → single ring update) 3. Broadcasts the complete ring snapshot atomically via the new LockRingUpdate message in KeepConnectedResponse Filers receive the ring as a complete snapshot and apply it via SetSnapshot, ensuring all filers converge to the same ring state without intermediate churn. This eliminates the double-churn problem where a rapid drop+join would fire two separate ring mutations, each triggering lock transfers and disrupting ownership on surviving nodes. * dlm: track ring version, reject stale updates, remove dead code SetSnapshot now takes a version parameter from the master. Stale updates (version < current) are rejected, preventing reordered messages from overwriting a newer ring state. Version 0 is always accepted for bootstrap. Remove AddServer/RemoveServer from LockRing — the ring is now exclusively managed by the master via SetSnapshot. Remove the candidateServers map that was only used by those methods. * dlm: fix SelectLocks data race, advance generation on backup insert - SelectLocks: change RLock to Lock since the function deletes map entries, which is a write operation and causes a data race under RLock. - InsertBackupLock: advance nextGeneration to at least the incoming generation so that after failover promotion, new lock acquisitions get a generation strictly greater than any replicated lock. - Bump replication failure log from V(1) to Warningf for production visibility. * dlm: fix SetSnapshot race, test reliability, timer edge cases - SetSnapshot: hold LockRing lock through both version update and Ring.SetServers() so they're atomic. Prevents a concurrent caller from seeing the new version but applying stale servers. - Transfer window test: search for a key that actually moves primary when filer4 joins, instead of relying on a fixed key that may not. - renewLock redirect: pass the existing token to the new primary instead of empty string, so redirected renewals work correctly. - scheduleBroadcast: check timer.Stop() return value. If the timer already fired, the callback picks up latest state. - FlushPending: only broadcast if timer.Stop() returns true (timer was still pending). If false, the callback is already running. - Fix test comment: "idempotent" → "accepted, state-changing". * dlm: use wall-clock nanoseconds for lock ring version The lock ring version was an in-memory counter that reset to 0 on master restart. A filer that had seen version 5 would reject version 1 from the restarted master. Fix: use time.Now().UnixNano() as the version. This survives master restarts without persistence — the restarted master produces a version greater than any pre-restart value. * dlm: treat expired lock owners as missing Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> * dlm: reject stale lock transfers Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> * dlm: order replication by generation Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> * dlm: bootstrap lock ring on reconnect Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> --------- Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>	2026-03-30 23:29:56 -07:00