Commit Graph
2 Commits
Author SHA1 Message Date
Chris Lu 34f9b91d69 fix(storage): never let an empty .dat delete healthy distributed EC shards (#9930)
* fix(storage): never let an empty .dat delete healthy distributed EC shards

A leftover empty .dat stub (a phantom from the pre-fix loader; zero
needles) next to a distributed EC volume's local shards made startup
classify the volume as an interrupted local encode: validateEcVolume
requires >= dataShards local shards when a .dat is present, fails with
the 1-2 shards a distributed volume keeps per disk, and the cleanup
deletes those shards -- the only copies of that part of the volume.
Repeated across restart waves this destroys enough shards cluster-wide
to make the volume unrecoverable.

Go:
- loadExistingVolume: hoist the empty-stub sweep above the EC presence
  checks. Previously the .vif-next-to-.ecx guard returned before the
  sweep ever ran, so exactly the dangerous layout (stub + .ecx + local
  shards) kept its stub and then lost its shards in loadAllEcShards.
- validateEcVolume / checkDatFileExists: treat a .dat <= a superblock
  (zero needles) as absent. An empty .dat cannot be the encode source,
  so it must never gate shard deletion; this also covers stubs without
  a .vif, which the sweep cannot prove are EC leftovers.

Rust mirror (seaweed-volume): the same gate in validate_ec_volume and
check_dat_file_exists (the Rust sweep already ran before validation);
the volume-load skip keeps a plain existence check so fresh,
needle-less volumes still load.

Regression tests in Go and Rust reproduce the production layout (a
zero-byte .dat beside .ecx/.ecj and two shards of a 10+4 volume, with
and without a .vif) and fail without the fix with the shards deleted.

* fix(ec): gate source volume deletion on a recoverable shard set

After EC encode, the shell command and the (plugin) worker task refused
to delete the source volume unless every shard was present, and aborted
otherwise -- leaving the source .dat next to live shards, exactly the
mixed state the startup cleanup mishandles.

Replace the full-set requirement with a recoverability gate shared by
both callers (RequireRecoverableShardSet): deleting a non-empty source
.dat requires at least dataShards distinct shards cluster-wide. Below
that the source is kept and the encode fails as before. A degraded but
recoverable set (>= dataShards, < total) now proceeds with a warning
instead of aborting: the missing shards can be rebuilt from the
survivors, while keeping the source would preserve the dangerous mixed
state. Empty stub replicas are still swept unguarded (OnlyEmpty) -- an
empty .dat has nothing to lose.

dataShards/totalShards stay parameters so enterprise custom EC ratios
share the helper verbatim.

* test(ec): use recoverable shard verification gate
2026-06-11 20:26:20 -07:00
Chris Lu 3a8389cd68 fix(ec): verify full shard set before deleting source volume (#9490) (#9493)
* fix(ec): verify full shard set before deleting source volume (#9490)

Before this change, both the worker EC task and the shell ec.encode
command would delete the source .dat as soon as MountEcShards returned —
even if distribute/mount failed partway, leaving fewer than 14 shards
in the cluster. The deletion was logged at V(2), so by the time someone
noticed missing data the only trace was a 0-byte .dat synthesized by
disk_location at next restart.

- Worker path adds Step 6: poll VolumeEcShardsInfo on every destination,
  union the bitmaps, and refuse to call deleteOriginalVolume unless all
  TotalShardsCount distinct shard ids are observed. A failed gate leaves
  the source readonly so the next detection scan can retry.
- Shell ec.encode adds the same gate after EcBalance, walking the master
  topology with collectEcNodeShardsInfo.
- VolumeDelete RPC success and .dat/.idx unlinks now log at V(0) so any
  source destruction is traceable in default-verbosity production logs.

The EC-balance-vs-in-flight-encode race is intentionally left for a
follow-up; balance should refuse to move shards for a volume whose
encode job is not in Completed state.

* fix(ec): trim doc comments on the new shard-verification path

Drop WHAT-describing godoc on freshly added helpers; keep only the WHY
notes (query-error policy in VerifyShardsAcrossServers, the #9490
reference at the call sites).

* fix(ec): drop issue-number anchors from new comments

Issue references age poorly — the why behind each comment already
stands on its own.

* fix(ec): parametrize RequireFullShardSet on totalShards

Take totalShards as an argument instead of reading the package-level
TotalShardsCount constant. The OSS callers continue to pass 14, but the
helper is now usable with any DataShards+ParityShards ratio.

* test(plugin_workers): make fake volume server respond to VolumeEcShardsInfo

The new pre-delete verification gate calls VolumeEcShardsInfo on every
destination after mount, and the fake server's UnimplementedVolumeServer
returns Unimplemented — the verifier read that as zero shards on every
node and aborted source deletion. Build the response from recorded
mount requests so the integration test exercises the gate end-to-end.

* fix(rust/volume): log .dat/.idx unlink with size in remove_volume_files

Mirror the Go-side change in weed/storage/volume_write.go: stat each
file before removing and emit an info-level log for .dat/.idx so a
destructive call is always traceable. The OSS Rust crate previously
unlinked them silently.

* fix(ec/decode): verify regenerated .dat before deleting EC shards

After mountDecodedVolume succeeds, the previous code immediately
unmounts and deletes every EC shard. A silent failure in generate or
mount could leave the cluster with neither shards nor a valid normal
volume. Probe ReadVolumeFileStatus on the target and refuse to proceed
if dat or idx is 0 bytes.

Also make the fake volume server's VolumeEcShardsInfo reflect whichever
shard files exist on disk (seeded for tests as well as mounted via
RPC), so the new gate can be exercised end-to-end.

* fix(ec): address PR review nits in verification + fake server

- Drop unused ServerShardInventory.Sizes field.
- Skip shard ids >= MaxShardCount before bitmap Set so the ShardBits
  bound is explicit (Set already no-ops on overflow, this is for
  clarity).
- Nil-guard the fake server's VolumeEcShardsInfo so a malformed call
  doesn't panic the test process.
2026-05-13 19:29:24 -07:00