Commit Graph
10 Commits
Author SHA1 Message Date
Chris Lu 88c873ecd4 ec: uniform shard block layout (#10932)
* ec: uniform shard block layout

An EC volume is striped as 1GiB blocks until less than one row remains, then
1MiB blocks, and consecutive blocks land on different shards. With ec.encode's
-fullPercent 95 against the 30GiB default limit, ~30% of every volume sits in
that 1MiB tail, so a 4MB filer chunk there is five stripes on five servers.

New encodes now use one block per shard, sized ceil(datSize/dataShards) rounded
up to 1MiB and recorded in the .vif (EcShardConfig.block_size, also carried by
the .ecsum manifest). A needle now maps to one shard unless it is larger than
the block or straddles a boundary. The chosen size equals the legacy layout's
padded shard length for every input, so shard sizes, capacity math, and the
shard-size credibility checks are unchanged; only the byte placement moved.

Reads, decode, and scrub resolve the block sizes from the volume's .vif;
absence keeps the legacy interpretation, so existing EC volumes read exactly as
before. Rebuild is layout-agnostic. weed fix -ecx recovers the layout from the
.vif, else the .ecsum sidecar, and with neither de-stripes under both candidate
layouts and keeps the one that indexes more valid needles.

Same change in the Rust volume server, which now also streams the encode in
256KB sub-batches like Go instead of allocating whole blocks, and computes the
large-row count as shardSize/largeBlock to match Go on exact multiples. On a
26MB fixture both encoders produce byte-identical shards, and a Go-written .vif
parses in Rust with the block size intact.

* ec: resolve the rust ecx rebuild through the recorded layout

The Rust rebuild path regenerated a lost .ecx by scanning the logical .dat
through a hand-rolled pure-1MiB striping, which was already wrong for legacy
volumes with large-block rows and is wrong for any uniform volume with a block
past 1MiB. Route the scan through locate_data with the .vif-recorded block
size, the same mapping the read path uses. Also seed the new tests' random
data instead of the deprecated global math/rand.Read.

* ec: fail the Rust ecx rebuild on any shard read error

A read error mid-scan published the entries collected so far as a
successful .ecx, and read_at's byte count was ignored so a legal short
read passed as complete — a truncated or failing shard could produce a
silently incomplete recovery index. Exact-read semantics in
read_from_data_shards, error propagation in the needle walk, and a
truncated-shard regression test.

* ec: fail the mount on an unreadable or malformed vif

Both servers silently fell back to the legacy layout when an existing
.vif could not be read or parsed. Every new encode records a positive
uniform block size there, so the fallback mounted the same shards with
legacy offset math and could return wrong data. Absent stays legal
(legacy volumes predate the sidecar), and a zero-byte stub still reads
as absent (Go's MaybeLoadVolumeInfo convention, now mirrored in Rust);
a present-but-unreadable or malformed .vif fails the mount instead.

* ec: bound the reconstruct fan-out of one needle's intervals

A degraded interval fans out a read to every reachable shard location, each
with a buffer the size of the interval. Reading a needle's intervals in
parallel multiplied that by the interval concurrency: a needle spanning 8
blocks could hold 8 x MaxShardCount remote reads and buffers at once, where
the sequential version peaked at MaxShardCount. Give each needle a single
reconstruct budget its intervals share, held for the buffer's lifetime, so
separate reads stay independent but one read cannot multiply its own
fan-out.

* ec: drop the duplicated shard-size formula

calculateExpectedShardSize reimplemented the padding rule that
UniformBlockSize already owns — TestUniformBlockSizeMatchesLegacyShardSize
asserts the two agree for every input — so a change to the rule would have
had to be made in both. Defer to the helper, keeping the historic answer for
an empty .dat.

* ec: resolve the shard block layout from whatever records it

Four places still answered the layout question by inference when a record of
it was available, or accepted an answer that was not one:

- A mount with no .vif defaulted to the legacy layout; the bitrot sidecar
  records the same config at encode time, so take it when present, as
  weed fix -ecx already does. The vif itself is now parsed once per mount
  rather than twice.
- The Rust ecx rebuild derived its row count from the padded shard extent,
  which under the legacy layout reads a shard that is an exact large-block
  multiple as one row too many. Pass the encode-time .dat size from the .vif
  and keep the extent as the fallback.
- weed fix -ecx read the block size outside the EC-config guard (collapsing
  the unknown sentinel into a definitive legacy), only wrote the recovered
  layout back when the .vif was absent rather than unusable, and broke a
  scan tie by candidate order instead of the documented reach.
- The uniform layout tripped writeDatFile's large-block ambiguity guard,
  which cannot apply when the large and small blocks are the same size.

* ec: give the index-recovery tests a parseable vif

The fixtures wrote the literal bytes "volinfo" as the source .vif and the
recovery copies it verbatim, so the receiving server then mounted the volume
from a .vif it could not parse. That used to pass by silently defaulting to
the legacy layout; a mount now refuses a vif it cannot read, which is what
the tests were exercising all along without meaning to.

* ec: validate the layout a vif records, not just its syntax

Review follow-ups on the mount-strictness change:

- A .vif can parse and still record a block size no encoder could have
  produced (negative, or not a whole number of small blocks). Both servers
  took it and mapped every read through it. ValidateBlockSize / the Rust
  mirror now refuse the mount, the same way an unparseable vif does; 0 stays
  valid as the legacy two-tier layout.
- The bitrot-sidecar fallback accepted parity_shards == 0 and summed the
  counts in their own width, so values near the ceiling wrapped past the
  MaxShardCount bound. Require both counts and sum in a wider type.
- weed fix -ecx treated a config with only DataShards > 0 as usable, so a
  half-written .vif suppressed the recovery paths AND survived the rewrite.
  Require a complete, in-range config before trusting it.
- Returning the vif-load error left the .ecx and .ecj descriptors open;
  repeated mount attempts on malformed metadata could exhaust them.

* ec: refuse to act on a layout the metadata does not establish

- The worker encode only logged a failed .vif write and skipped it in the
  distribution set, and treated the .ecsum write as best-effort. A worker
  whose disk filled after the much larger shards landed could still
  distribute, mount, verify shard inventory, and delete the source replicas —
  leaving holders with shards whose geometry nothing records. Both writes and
  both inclusions are encode success conditions now.
- A generation-matching .ecsum that disagreed with the .vif geometry only
  disabled checksums in Go, and in Rust was not compared at all, so
  protection stayed On while reads used the other layout. Both files record
  the layout their generation was encoded with, so a disagreement now fails
  the mount.

* ec: reject an invalid recorded block size in weed fix -ecx

A .vif with valid shard counts but a negative or unaligned block size was
marked usable: a positive invalid value pinned the scan to a geometry that
de-stripes to garbage, and a negative one ran the dual scan but left the
invalid .vif in place afterwards. Validate it with the same rule the mount
applies, and when it fails leave the layout unknown so the scan recovers it
and the file is rewritten.

* ec: validate the sidecar layout weed fix -ecx recovers from

The .ecsum fallback was taken on DataShards > 0 alone, so a CRC-valid
sidecar carrying the wrong generation, an incomplete ratio, or an unaligned
block size would pin the reconstruction to one incorrect uniform-layout
candidate instead of letting the dual scan decide. Require generation 0, a
complete in-range ratio, and a valid block size; anything less leaves the
layout unknown, which is the answer that still recovers by scanning.

* ec: let only a genuinely absent sidecar choose the legacy layout

With no .vif the bitrot sidecar is the only record of a volume's layout, and
the mount fallback read a failed load, an unusable config, or a sidecar
stamped for another generation as "assume legacy". A uniform generation-0
volume could therefore mount with legacy or another generation's geometry and
answer reads with the wrong bytes. Present-but-unusable now fails the mount;
only actual absence keeps the legacy defaults. Shared as
EcShardConfigFromSidecar so every caller reads the sidecar the same way.

* ec: treat a recorded-but-impossible layout as corruption, not as legacy

- A .vif whose ecShardConfig is PRESENT but records an impossible ratio was
  answered with the default 10+4 and the legacy block layout, in both
  languages. That reads a uniform volume's shards at the wrong offsets and
  returns the wrong bytes. Only an entirely absent config still means "this
  predates the record"; a present one that cannot be true fails the mount.
- The shard-count bound summed two uint32 counts as int, which wraps on a
  32-bit build: 0x7fffffff + 0x7fffffff lands at -2 and slips under
  MaxShardCount. ValidEcShardCounts sums in uint64, and every EC call site
  that checked a recorded ratio now goes through it.

* ec: rebuild on the geometry the sidecar records, and flag it when it disagrees

The rebuild RPC passes BackgroundECContext, so RebuildEcFiles resolves the
layout itself — and it resolved a missing or invalid .vif to the default 10+4
with the legacy block size. Two consequences: a 12+4 volume was reconstructed
through a 10+4 matrix, which produces wrong bytes and never regenerates
shards 14-15; and the chosen geometry then contradicted a valid uniform
sidecar, which loadRebuildSidecar reported as BitrotOff — silently skipping
the input and regenerated-shard checksum checks precisely when the volume had
already lost its metadata.

The layout now resolves from the bitrot sidecar (found across the server's
disks, not just beside the base name) before falling back to the defaults,
and a present-but-impossible ratio fails instead of being replaced. A sidecar
that contradicts the chosen geometry is BitrotInvalid, which the existing
unsafeIgnoreSidecar override still lets an operator push past.

* ec: let the Rust rebuild read metadata off a sibling disk

read_ec_shard_config searches only the location the rebuild writes into, so a
volume whose .vif or generation-0 .ecsum sits on another of the server's
disks resolved to the default 10+4 with the legacy block layout — the Rust
half of the geometry-guessing the Go rebuild just stopped doing. It then
reconstructs a custom-ratio or uniform volume through the wrong
Reed-Solomon matrix and de-striping geometry.

The rebuild now looks for the .vif in its own location and then each sibling,
falls back to the generation-0 sidecar wherever that lives, and only defaults
when neither exists anywhere. The encode-time .dat size the ecx rebuild needs
is resolved the same way.

* ec: resolve a rebuild's vif from every directory that may hold it

RebuildEcFiles probed only <data-base>.vif. The caller knows the selected
location's index directory and the sibling locations, but passed neither for
metadata: additionalDirs carried shard directories only, and were searched
for shards and the checksum sidecar. A split -dir/-dir.idx layout, or a disk
holding only shards, therefore resolved a pre-sidecar custom-ratio volume to
10+4 and reconstructed through the wrong matrix — never regenerating shards
14-15.

The caller now hands over the index and sibling directories, and the resolver
probes the vif across all of them, matching what the Rust resolver already
does for both the vif and the sidecar.

* ec: make every rebuild consumer agree on the layout it resolved

- The post-rebuild bitrot backfill re-derived the geometry from this
  directory's .vif alone and dropped the block size entirely, so a rebuild
  that resolved its layout from a sibling, the sidecar, or a uniform vif wrote
  a manifest describing a DIFFERENT layout — one later mounts reject, or that
  covers only the default shard count. The layout is resolved once now,
  through an exported ResolveRebuildECContext, and the rebuild and the
  backfill share that answer.
- The Rust rebuild collected only each location's data directory, so a
  sibling's INDEX directory — where a split -dir/-dir.idx layout keeps
  .ecx/.ecj/.vif — was never probed, and a custom-ratio volume still resolved
  to 10+4 with the legacy layout. Both directories of every location are
  carried now, deduped against the rebuild's own.
- A shard delivery can bring the checksum manifest with it, but the receive
  path only writes the file: a server that already had the volume mounted kept
  its resolved protection state (off) until a remount. The mount RPC
  re-resolves it once the shards it describes have been added.

* ec: cover the rebuild's directory search with tests

Reviewers flagged the sibling index directory twice, and the fix that
closed it had no test of its own: the assembly sat inline in the rebuild
handler, reachable only through a gRPC call against a populated store.
Lifting it into rebuildSearchDirs / select_rebuild_location makes the
rule assertable — a sibling contributes BOTH its data and its index
directory, a shared index directory is listed once, and the rebuild's own
data directory never repeats.

Writing the Rust cases surfaced that the two implementations do not agree
on where the rebuild's own index directory belongs, and both are right:
Go's resolver takes a single directory list, so that directory has to be
inside it, while Rust's takes the rebuild's data and index directories as
their own arguments and would search them twice. The tests now state
which contract each side is holding to, so neither drifts into the
other's shape.

Pure refactor otherwise; no behaviour change.

* ec: search the index directory for the layout sidecar

The Rust resolver looked for the generation-0 .ecsum in the rebuild's
data directory and the sibling list, but not in the rebuild's own index
directory — while the .vif lookup directly above it did, and Go's
findBitrotSidecar has always checked both bases. On a split -dir/-dir.idx
location that directory is where the metadata lives, and callers leave it
out of the sibling list precisely because it is passed here separately,
so nothing searched it.

With no .vif anywhere the sidecar is the only surviving record of the
layout. Missing it resolved a 12+4 uniform volume to 10+4 with the legacy
striping — the test added here fails with (10, 4, 0) against the old
code — and the rebuild then reconstructs through the wrong matrix and
writes .ecx offsets that no reader can follow.

* ec: let the rebuild see its own index directory

The Rust rebuild takes a single flat directory list — the shape Go's
RebuildEcFiles uses — so it cannot be handed the rebuild location's index
directory separately the way the layout resolvers are, and the handler
was passing the sibling list, which deliberately omits exactly that
directory. On a split -dir/-dir.idx location that is where .ecx and .vif
live, so the shard and index lookups could not see them.

Go has always carried that directory in additionalDirs; this lines the
two call sites up.

* ec: let a config-free vif fall through to the layout sidecar

A .vif that carries no ecShardConfig answers nothing about the layout, so
it is no more informative than an absent one — but both trees treated its
mere existence as the end of the search. Go went straight to the 10+4
legacy defaults without consulting the sidecar at all; Rust returned
whatever ec_shard_config_from could make of a single directory. A 12+4
uniform volume with a legacy config-free vif therefore resolved as 10+4
legacy, and every read landed at the wrong shard offset.

The sidecar lookup was also single-directory on both sides, while a split
-dir/-dir.idx layout keeps .vif and .ecsum with the INDEX. Go's
findBitrotSidecar has always taken both bases; the callers here passed
only the data base, and the Rust bitrot resolver derived its path from
the data base alone. Rust's layout resolver now takes a candidate
directory list — data, index, then any siblings — and searches all of it,
which also removes the early return that made the vif's presence
decisive.

load_vif_info_across_dirs reported `dir` even when load_vif_info had
found the vif in `dir_idx`. Nothing reads that field today, so this
changes no behaviour; it stops the next caller that resolves the rest of
the volume's metadata against the answer from being sent to a disk
holding none of it.

Absence stays legal throughout: a volume with neither record is genuinely
legacy. Present-but-unusable still fails the mount, now in the
config-free-vif branch too.

* ec: activate a delivered sidecar on every per-disk runtime

A vid mounts as one EcVolume per disk, each with its own resolved
protection state, but the post-delivery reload used the first-match
lookup and so touched exactly one of them. The siblings kept reporting no
protection until a remount — and since shard distribution deduplicates
the metadata files onto the first target disk for a node, the runtime
that got the .ecsum is not necessarily the one the lookup returns.

Iterate every runtime instead, via a new FindAllEcVolumes and its Rust
mut equivalent. Combined with each runtime now resolving its sidecar
against its index directory as well as its data directory, a server
sharing one -dir.idx across its disks activates all of them from the
single delivered copy.

The Rust volume server had no post-mount reload at all; it gets one here,
matching Go.

* ec: resolve the delivered sidecar across every EC metadata directory

Reloading every per-disk runtime, added last round, did not by itself
make the delivered manifest reachable. Startup mirroring copies
.ecx/.ecj/.vif to every shard-bearing disk so each mounts
self-contained, but deliberately not .ecsum, and a repair delivers
exactly one copy. Each runtime was resolving against its own two
directories, so every sibling of the disk that received the file kept
reporting no protection however often it reloaded.

Resolve one authoritative copy across every EC metadata directory
instead of duplicating the file. Mirroring .ecsum would have to keep
pace with a file that is rewritten as shards are repaired, and would not
help the reported case at all: the delivery happens at runtime, and
mirroring only runs at startup.

The regression test pins both halves — a reload restricted to the
volume's own directories still finds nothing, and the same reload
given the server's metadata directories turns protection on.

* ec: ask every directory before writing a TOFU baseline

After a rebuild the opportunistic backfill asks whether this volume
already has a checksum manifest, and answered from the data base alone.
A split -dir/-dir.idx layout keeps the sidecar with the index, and a
multi-disk server may keep it on a sibling, so an existing manifest read
as absent.

The consequence is worse than a missed read. On a false "no" the backfill
writes a fresh sidecar at the data base from whatever the shards say right
now — and the data base is the first candidate every resolver checks, so
that TOFU baseline shadows the real manifest rather than sitting beside
it. A shard that was silently corrupt gets blessed, and the record that
would have caught it stops being consulted.

FindBitrotSidecar exports the search the package already used internally,
so the question is asked of the data base, the index base and the sibling
disks — the same candidates the rebuild resolves its layout from.

* ec: refuse a shard block size no encoder could have produced

weed fix -ecx derived one from the raw shard extent, so a truncated or
partially copied shard wrote a .vif that NewEcVolume then permanently
refuses — the volume the tool was run to rescue could never mount again.
An extent that is not a whole number of small blocks cannot have come
from a uniform encode, so it is no longer offered as a candidate, and
nothing unvalidated reaches the .vif.

Claude-Session: https://claude.ai/code/session_011FRRoNKBiGbH58rs2AQyA7

* ec: derive the .vif's dat size and block size from one measurement

VolumeEcShardsGenerate stat'ed the .dat before the encode while
WriteEcFiles stat'ed it again to size the blocks. A write landing
between the two produced a .vif whose own two fields describe different
files. WriteEcFiles now leaves both on the context, and fills a
placeholder context in place so the caller can read them back.

Claude-Session: https://claude.ai/code/session_011FRRoNKBiGbH58rs2AQyA7

* ec: keep the source volume until every holder serves its shard layout

The uniform layout rides in a .vif field older volume servers never
knew: they discard it, mount the shards as legacy and return wrong bytes
with nothing erroring, and the shard files are the same length either
way so no other check notices. The upgrade order lived only in the
release note. VolumeEcShardsInfo now reports the block size the holder
actually serves, in both the Go and Rust servers, and the pre-delete
verification refuses to drop the source unless every reachable holder
echoes the one the shards were encoded with — while a rollback still
exists. A server that predates the field answers 0, which is the
negative answer.

Claude-Session: https://claude.ai/code/session_011FRRoNKBiGbH58rs2AQyA7

* ec: drop the rebuild's dead block-size parameters

generateMissingEcFiles never reads largeBlockSize/smallBlockSize —
Reed-Solomon reconstruction is layout-agnostic — so passing the legacy
constants only advertised a layout the rebuild does not use. Also move
UniformBlockSize's doc off ValidateBlockSize.

Claude-Session: https://claude.ai/code/session_011FRRoNKBiGbH58rs2AQyA7

* ec: warn about EC defaults only when the mount used them

The "vif file not found, using defaults" warning fired even after the
bitrot sidecar supplied a non-default layout, sending anyone triaging
wrong bytes after the legacy layout the volume never mounted on.

Claude-Session: https://claude.ai/code/session_011FRRoNKBiGbH58rs2AQyA7

* ec: stat the distributed bitrot sidecar once

The strict check re-stat'ed the file immediately before the stat that
already gates inclusion, and a failed sidecar write now fails the encode
outright, so the first could only fire on a deletion between the two
lines.

Claude-Session: https://claude.ai/code/session_011FRRoNKBiGbH58rs2AQyA7

* ec: say what the reconstruct budget actually bounds

A shard's buffer stays in bufs until its interval reconstructs, which is
after the read that filled it released its permit, so the semaphore
bounds round trips in flight and not retained bytes. Peak memory is the
intervals reconstructing at once times the shards each reaches times the
interval size.

Claude-Session: https://claude.ai/code/session_011FRRoNKBiGbH58rs2AQyA7

* test: let the fake volume server report its delivered EC layout

The pre-delete verification now asks each holder which shard block
layout it serves, and a fake that always answered "unset" looked exactly
like a volume server too old to know the field. Distribution ships the
.vif to every holder alongside its shards, so read the layout back out
of it as a real holder does.

Claude-Session: https://claude.ai/code/session_011FRRoNKBiGbH58rs2AQyA7
2026-08-28 20:46:59 -07:00
Chris LuandLisandro Pin fcc2ea61d3 ec: scrub a volume through its parity data (#11006)
* Introduce a new `READS` scrub mode.

`READS` performs a full volume scrub but, unlike `FULL`, it will attempt to
reconstruct data for missing/damaged shard intervals from other shards in the cluster
when necessary.

The goal of this check is to ensure that EC volume contents _are readable by Seaweed_
even on a degraded storage state, by exercising parity data which is not read in `FULL`
mode. This is useful not only to validate data is user-readable, but also to detect potential
parity shard issues which may be difficult to pinpoint otherwise - particularly for older
volumes lacking sidecar data, and hence unaffected by `CHECKSUM` scrubs.

For regular volumes, this operation is equivalent to `FULL`.

Example:

```
> ec.shard.unmount --volumeId=1 --shardId=0,3,11 --delete --apply
Live shard topology for volume ID 1 (14 shards):
	0@10.200.18.89:9001
	1@10.200.18.89:9002
	2@10.200.18.89:9003
	3@10.200.18.89:9004
	4@10.200.18.89:9005
	5@10.200.18.89:9006
	6@10.200.18.89:9007
	7@10.200.18.89:9008
	8@10.200.18.89:9009
	9@10.200.18.89:9013
	10@10.200.18.89:9010
	11@10.200.18.89:9011
	12@10.200.18.89:9012
	13@10.200.18.89:9020

Will unmount + delete 3 shard(s):
	0@10.200.18.89:9001
	3@10.200.18.89:9004
	11@10.200.18.89:9011

Unmounting shard 0@10.200.18.89:9001 for volume ID 1...
Deleting shard 0@10.200.18.89:9001 for volume ID 1...
Unmounting shard 3@10.200.18.89:9004 for volume ID 1...
Deleting shard 3@10.200.18.89:9004 for volume ID 1...
Unmounting shard 11@10.200.18.89:9011 for volume ID 1...
Deleting shard 11@10.200.18.89:9011 for volume ID 1...

All done!

> ec.scrub --volumeId=1 --node=10.200.18.89:9002 --mode=full
using FULL mode
Scrubbing 10.200.18.89:9002 (1/1)...
Scrubbed 6 EC files and 1 volumes on 1 nodes

Got scrub failures on 1 EC volumes and 1 EC shards :(
Affected volumes: 10.200.18.89:9002:1
Affected shards:  10.200.18.89:9002:1:0

> ec.scrub --volumeId=1 --node=10.200.18.89:9002 --mode=reads
using READS mode
Scrubbing 10.200.18.89:9002 (1/1)...
Scrubbed 6 EC files and 1 volumes on 1 nodes
```

* ec: report the shards a READS scrub had to rebuild

A READS scrub that recovers an interval was recording nothing, so a volume
missing three shards came back clean and nobody repaired it. The unreadable
shard is now recorded before the rebuild is attempted: READS reports the same
broken shards as FULL and differs only in whether the needles themselves
failed, which is the signal worth having - shards are gone, data is still
there.

forceDeletedNeedlesCheck now applies to READS as well, in the shell and in the
RPC guard: it runs the same needle walk as FULL.

Regenerated the proto instead of hand-editing it, so the pancis typo (which
protoc-gen-go-grpc emits into eight other files here) and the header whitespace
stay as generated.

Mirrors into the Rust volume server, which also now honors
force_deleted_needles_check rather than hardcoding it off.

Claude-Session: https://claude.ai/code/session_014yMNebkUjSbx9sfUCWJJtq

* ec: answer a deleted needle from a READS rebuild as deleted

#11020 gave the Rust recovery a deleted flag alongside its bytes, and it
answers a deleted needle with no bytes at all. The READS scrub appended that
empty answer, which does not compile against the new signature and, once it
did, would leave the needle short and report the size mismatch as damage.

Zero-fill the interval instead, the way the direct read beside it already
does: the assembled needle then reaches read_bytes as the delete-state
mismatch the walk already tolerates. Go takes the same branch off the flag
its recovery returns, rather than discarding it.

Claude-Session: https://claude.ai/code/session_014yMNebkUjSbx9sfUCWJJtq

---------

Co-authored-by: Lisandro Pin <lisandro.pin@proton.ch>
2026-08-28 16:42:34 -07:00
Chris Lu cd5013f116 Re-check an EC shard map a failed read has disproved (#11023)
* Re-check an EC shard map a failed read has disproved

A read that fails against a cached location drops that shard from the map,
which leaves it one short of complete -- and a map one short is trusted for
seven more minutes. So a moment's trouble between volume servers cost
minutes in which every read of that shard skipped the direct fetch and paid
for a Reed-Solomon recovery instead, at DataShards times the memory and the
peer load.

Mark the map when a read disproves it, and re-check a marked map on the
same eleven-second footing as one that never had enough shards to begin
with. The mark clears on refresh, so it buys one prompt re-check rather
than a master lookup per read. The tiers move into a helper; they were
three overlapping conditions in one expression, and the reading of them
was not obvious.

Rust keeps the entry rather than dropping it -- a dead peer fails fast on
the next attempt, and it was the freshness window, not the entry, hiding a
shard that had moved.

Claude-Session: https://claude.ai/code/session_01SM5ARdPvFcnvGWNpBPgNRN

* Invalidate the location of an EC shard whose own read failed

Recovery fans out to the other shards, so the one whose direct read just
failed is the only location nothing ever invalidates: a shard that moved to
another server was reconstructed on every read until the map's own window
expired, up to thirty-seven minutes for a map still complete. Mark the map
there too. The entry stays -- a moved shard's old holder fails fast, and
the next refresh is seconds away.

Claude-Session: https://claude.ai/code/session_01SM5ARdPvFcnvGWNpBPgNRN

* Consume the stale mark before the lookup, not after

A read that fails while the master is answering has disproved the very map
that answer is about to install, and clearing the mark on the refresh's
return swallowed it. Clear it where it is acted on instead. A lookup that
then fails loses the mark, which costs nothing: the refresh time is only
advanced on success, so the next read looks up regardless.

Claude-Session: https://claude.ai/code/session_01SM5ARdPvFcnvGWNpBPgNRN

* Judge the shard map and consume its mark in one critical section

Reading the mark and clearing it were two separate acquisitions, so a mark
raised between them was cleared by a refresh that had not seen it. In Go
that gap was a few instructions; in Rust the mark was read when the read
first snapshotted the volume and cleared at the decision point, with the
local interval reads in between. Take both under one hold. Rust needs a
mutex rather than an atomic to do it, and no longer carries the mark
through the snapshot.

Claude-Session: https://claude.ai/code/session_01SM5ARdPvFcnvGWNpBPgNRN

* Put the stale mark back when the lookup does not answer for it

Consuming the mark up front assumed the lookup would supersede it. A
lookup that fails, or comes back with fewer than DataShards holders,
supersedes nothing: the map is unchanged, its refresh time unadvanced, and
with the mark gone the map a read had disproved is trusted for its full
window again on the strength of a lookup that never landed. Put the mark
back on both branches.

Claude-Session: https://claude.ai/code/session_01SM5ARdPvFcnvGWNpBPgNRN
2026-08-28 15:43:05 -07:00
Chris Lu 95248f7492 Bound the memory an EC shard recovery holds (#11020)
* Reconstruct an EC shard from the shards already on this server

recoverOneRemoteEcShardInterval only ever fanned out to the cached shard
locations, so a server holding shards of the volume still fetched them
over gRPC from itself -- and when the peers were unreachable it could not
reconstruct at all, even holding the whole volume on local disk. Seed the
Reed-Solomon buffers from the locally mounted shards first; each one is a
peer round trip, and an interval-sized buffer, the fan-out no longer needs.

Claude-Session: https://claude.ai/code/session_01SM5ARdPvFcnvGWNpBPgNRN

* Fetch only the EC shards reconstruction still needs

The recovery fan-out read every surviving shard, so a 10+4 volume pulled
13 interval-sized buffers to feed Reed-Solomon 10 -- a third more memory
held, and a third more load asked of peers that were, by definition,
already having trouble. Fetch what is missing, and widen only when some of
those reads fail. A shard reporting the needle deleted ends the walk: the
rest would only answer the same.

Claude-Session: https://claude.ai/code/session_01SM5ARdPvFcnvGWNpBPgNRN

* Bound the bytes EC recovery holds in flight

Recovery is the one read path that multiplies the served bytes: it holds
an interval-sized buffer per shard until Reed-Solomon runs, and a peer that
is slow to fail keeps them all alive for the whole gRPC timeout. Nothing
bounded how many of those fan-outs ran at once, so a transient problem
between volume servers turned every read into a DataShards-fold allocation
and the server died of it -- 64 concurrent 4MB intervals pin 3.6GB, and
that is a small burst.

Charge each recovery against a process-wide budget, so a burst queues on
the semaphore instead of on the heap.

Claude-Session: https://claude.ai/code/session_01SM5ARdPvFcnvGWNpBPgNRN

* Answer a deleted EC needle as deleted, not as a failed recovery

A holder reporting the needle deleted is authoritative: deletes are never
invented and never undone. Recovery already collected that flag, then
dropped it on the branch where too few shards came back -- so a read of a
deleted needle that had to recover surfaced as "cannot recover shard", and
the volume server answered 500 where it owed a 404. Carry the flag out of
the shortfall, and let it decide ahead of the error it came with.

Claude-Session: https://claude.ai/code/session_01SM5ARdPvFcnvGWNpBPgNRN

* Check the encode run of a locally seeded EC shard in Rust

The Rust recovery seeded Reed-Solomon straight from the mounted shards,
without the encode-run check the remote reads and Go's
readLocalEcShardInterval both apply. A volume remounted from a newer
encode between the read's snapshot and its recovery would have fed
mixed-generation bytes into the reconstruction.

Claude-Session: https://claude.ai/code/session_01SM5ARdPvFcnvGWNpBPgNRN

* Say what the recovery budget actually guarantees

Claude-Session: https://claude.ai/code/session_01SM5ARdPvFcnvGWNpBPgNRN

* Seed Rust EC recovery from shards on every local disk

find_ec_volume returns the first disk's EcVolume, so a reconciled volume
whose shards are split across data dirs had the siblings ignored and could
report "cannot recover" while holding enough shards locally. Resolve each
shard together with the disk that owns it, the way Go's recovery already
does, and check that owner's encode run.

Claude-Session: https://claude.ai/code/session_01SM5ARdPvFcnvGWNpBPgNRN
2026-08-28 14:14:40 -07:00
Chris Lu 51eb5333d3 ec: read a needle's intervals in parallel (#10911)
* ec: read a needle's intervals in parallel

A needle spanning more than one EC block gets one interval per block, and
consecutive blocks live on different shards. We read those intervals in
sequence, so a 4MB chunk landing in a volume's 1MB small-block region cost
five round trips to five different servers.

Read them concurrently into disjoint slices of a single buffer, at most 8 in
flight. Same change in the Rust volume server's phase C.

* ec test: seed the random payload instead of the deprecated rand.Read
2026-08-24 14:03:44 -07:00
Chris Lu 8f2a2abae4 fix(ec): correct EC FULL scrub for deleted needles, shard-location cache, and parity coverage (#10152)
* fix(ec): correct EC FULL scrub for deleted needles + shard-location cache

Addresses review findings on the EC FULL distributed scrub:
- Remote EC reads now thread Go's (bytes, is_deleted) contract. A runtime EC
  delete keeps the .ecx size positive (the delete lives in .ecj/memory), so the
  raw-index walk verifies the needle, and its header interval is usually remote;
  the peer answers is_deleted with no payload. The scrub zero-fills that interval
  (so the needle reaches read_bytes -> SizeMismatch{0} -> the delete-state
  suppression), the serving direct read short-circuits to not-found, and
  reconstruction EXCLUDES the shard instead of feeding zeros into Reed-Solomon.
- The walk skips size.is_deleted() (not just is_tombstone), so a -originalSize
  .ecx entry (pre-encode delete) can't yield empty intervals or panic parse_header.
- Restore Go's < data_shards completeness guard (per-volume, custom-ratio aware)
  and per-shard merge in the location cache instead of clobber-with-partial.
- Abort the scrub with an error on mid-scan unmount instead of a false-CLEAN.
- Hoist the refreshed location map once instead of cloning it per needle.

Claude-Session: https://claude.ai/code/session_015EE9Sc9EvNp8BCVva4RKdo

* feat(scrub): keep RS parity check in EC FULL until CHECKSUM lands

The per-needle FULL walk only reads live data-shard intervals, so it can't catch
bitrot in a parity shard or an unwalked cold region. Run verify_ec_shards
alongside the walk, gated on all-shards-local (single-node EC), via spawn_blocking.
A deliberate temporary divergence from Go FULL; moves to mode 4 (CHECKSUM) once
the .ecsum subsystem lands.

Claude-Session: https://claude.ai/code/session_015EE9Sc9EvNp8BCVva4RKdo
2026-06-30 10:18:31 -07:00
Chris Lu d18b85ef61 feat(scrub): EC FULL scrub — distributed local+remote needle walk (#10149)
* feat(ec): add scrub_ec_volume_distributed (FULL EC scrub, local+remote)

Ports Go's Store.ScrubEcVolume: walk the raw .ecx, verify every needle across
local AND remote shards without decoding (report faults, don't heal), with the
#10130 deleted-needle size-mismatch suppression gated on a force flag. Reuses
the read path's lock-drop + no-reconstruct read_remote_ec_shard_interval so no
!Send store guard is held across an .await.

Walks the unmasked index (scrub_snapshot_under_lock locates from the raw
(offset, size), not locate_needle) so logically-deleted-but-present needles are
still byte-verified, matching Go. Refreshes shard locations once up front and
hard-fails on a master-lookup error rather than retrying per needle.

Claude-Session: https://claude.ai/code/session_015EE9Sc9EvNp8BCVva4RKdo

* feat(scrub): dispatch EC FULL (mode 2) to the distributed needle walk

FULL ran a local-only Reed-Solomon parity check; route it to the per-needle
local+remote walk instead, mirroring Go. The handler collects vids under a brief
lock then releases it: FULL self-locks per needle (it awaits remote reads),
INDEX/LOCAL re-acquire a brief lock. verify_ec_shards is retained but no longer
wired to a mode.

Claude-Session: https://claude.ai/code/session_015EE9Sc9EvNp8BCVva4RKdo
2026-06-30 03:29:46 -07:00
Chris Lu 2efc0e1656 ec: recover EC shards whose .ecx index lives only on a peer server (#10108)
* ec: recover EC shards whose .ecx index lives only on a peer server

A volume server that boots with EC shard files on disk but no .ecx index
on any local disk cannot mount the shards, so the master never learns
about them. ec.rebuild works off master-registered shards, so it sees the
volume as short and gives up even though the shard data is intact.

Add an operator-triggered recovery: VolumeEcShardsMount gains a
recover_missing_index flag that makes the volume server fetch the missing
.ecx (plus .ecj/.vif) from a peer holding it and mount the on-disk shards.
ec.rebuild runs this across the cluster before planning, so orphaned
shards register and the rebuild sees the true shard set.

.ecx is an immutable encode-time index, identical on every holder. .ecj
is a per-holder deletion journal that differs across holders, so the
recovered node adopts the source peer's deletion view, like a balanced or
rebuilt shard does.

* ec: mirror missing-index recovery into the Rust volume server

Port the #10104 recovery to seaweed-volume so the Rust volume server
self-heals the same layout: EC shards on disk with the .ecx index only on
a peer. Adds collect_ec_volumes_missing_index / mount_recovered_ec_shards
to the store, recover_missing_ec_indexes (master LookupEcVolume + peer
CopyFile fetch + mount) to the server, and the recover_missing_index flag
on VolumeEcShardsMount.

.ecx is the immutable encode-time index, identical on every holder. .ecj
is a per-holder deletion journal, so the recovered node adopts the source
peer's deletion view, matching the Go path.
2026-06-25 10:38:14 -07:00
Chris Lu 79ac279fe1 fix(ec): don't mix EC shards from different encode runs (#9880)
* feat(ec): add encode_ts_ns to EC shard metadata and the shard read RPC

EcShardConfig and VolumeEcShardReadRequest gain an int64 encode_ts_ns
(encode time in unix nanos). It rides in .vif and the read request so a
read can be scoped to the encode run that produced the index.

* fix(ec): stamp each encode and reject cross-run shard reads

Generate stamps EncodeTsNs into the volume's .vif. Reads carry it to the
shard's owning volume (resolved together via FindEcVolumeWithShard, so a
multi-disk server validates the disk that actually serves the bytes) and
reject a shard from a different encode run, recovering from parity. A
zero on either side (pre-upgrade volume) skips the guard.

* fix(ec): stamp the encode identity on the worker-generated .vif

The worker-local encode path now writes EncodeTsNs (and the resolved EC
ratio) into the .vif, so the read guard is not silently off for volumes
encoded by the maintenance worker.

* fix(ec): wipe stale EC artifacts before re-encoding

VolumeEcShardsGenerate evicts any in-memory EcVolume for the volume and
removes its on-disk shard/index/sidecar files before writing fresh ones,
so a retried encode never builds on a partial prior run and the unlink
frees the inodes instead of leaving open fds serving old bytes.

* fix(ec): unmount EC shards across all disks

UnmountEcShards walked only the first disk holding the shard, leaving a
duplicate copy mounted on a sibling disk (split-disk reconciled volumes)
still serving and heartbeating. Traverse every disk and emit one
deletion delta per disk.

* fix(ec): delete orphan shards without a local .ecx

deleteEcShardIdsForEachLocation gated shard-file removal on a local .ecx,
so it could not clean an orphan .ecNN left by a failed copy on a disk
with no index. Delete the requested shard files unconditionally; the
index-file (.ecx/.ecj/.vif) routing stays gated as before.

* fix(ec): clear stale EC shards cluster-wide before re-encoding

ec.encode unmounts and deletes EC shards for the target volumes on every
node before regenerating: fatal for the shards the topology reports
(mounted leftovers), best-effort for the rest (a sweep that catches
unmounted failed-copy orphans). A down node is a no-op.

* fix(ec): don't nil EC fds on close so reads can't race eviction

A reader resolves an EcVolume/shard under the lock then reads after it is
released, so an eviction that nils ecxFile/ecdFile would race that read
and panic. Close the fds without nilling the fields: the field is now
write-once (no data race) and a concurrent read hits a closed fd, getting
a clean error that the caller recovers from parity.

* fix(ec): wipe stale EC artifacts on every disk and surface failures

The pre-encode wipe only deleted beside the source volume, so a stale
shard on a sibling disk survived and could be mounted against the new
index at reconcile. Sweep every disk. Removal also ignored os.Remove
errors, reporting a failed cleanup as success and letting a stale shard
join the next generation; surface the first real failure (treating
already-gone as success) from removeStaleEcArtifacts and the shard delete.

* fix(ec): log when a local shard is skipped for a different encode run

The cross-run guard returned errShardNotLocal, indistinguishable in logs
from a genuinely-absent shard. Add a V(1) line naming both EncodeTsNs so
operators can tell "wrong encode generation" from "shard not here".

* fix(ec): surface metadata removal failures in the shard delete path

deleteEcShardIdsForEachLocation still dropped os.Remove errors on the
.ecx/.ecj/.vif/sidecar cleanup. A surviving stale .ecx is the orphan-index
condition this path prevents, so route those through removeFileIfExists and
return the first real failure instead of reporting cleanup as success.

* fix(ec): fail orphan cleanup when a reachable node's delete fails

The pre-encode orphan sweep swallowed every error for unreported (node,
volume) pairs. That is only safe for an unreachable node, which cannot
receive this encode's new generation. A reachable node whose delete
genuinely failed (permission/IO) keeps an orphan shard that a later copy
re-stamps with the new run's volume-level .vif identity, so the read guard
would accept stale data. Surface those; stay best-effort only for
unreachable nodes (gRPC Unavailable / no status).

* fix(ec): guard ecjFile under its lock in the EC delete path

EcVolume.Close nils ecjFile under ecjFileAccessLock; a delete that resolved
its .ecx lookup before a concurrent eviction (the generate-time
UnloadEcVolume) could then reach the journal append with a nil fd. Bail
with a clear "volume closed" error under the lock instead.

* fix(ec): reject an unstamped shard when the caller has an encode identity

The read guard required both identities nonzero, so a current (stamped)
caller accepted a holder with identity 0 and could be served a stale
pre-upgrade shard. Reject when the caller is stamped and the holder
differs (including unstamped); stay lenient only when the caller itself
has no identity (pre-upgrade reader). A skipped shard recovers from parity.

* fix(ec): full-teardown delete so cluster cleanup wipes a whole generation

The pre-encode cluster sweep deleted only the listed canonical shards on
remote nodes, leaving index/sidecar (and, on builds with versioned
generations, those too) behind. Add a full_teardown flag to
VolumeEcShardsDelete that evicts the volume and wipes every EC artifact for
it on every disk via removeStaleEcArtifacts; the shell and worker pre-encode
cleanup paths set it. Other delete callers (balance/decode/repair) are
unchanged.

* fix(ec): take ecjFileAccessLock before the nil-check in Sync and Close

Sync and Close read ev.ecjFile before acquiring ecjFileAccessLock while
Close nils it under the lock, a data race on the field. Take the lock
first, then nil-check inside, in both.

* fix(ec): acknowledge full_teardown so a pre-upgrade server can't fake success

An old volume server silently ignores full_teardown and returns success
for an ordinary delete, so the caller wrongly believes the generation was
wiped and copies a fresh gen-0 onto an unwiped node. Echo full_teardown_done
in the response; the worker destination cleanup fails when it is absent, and
the shell cluster sweep fails for a reported (mounted) leftover while staying
best-effort for an unreported node. encode_ts_ns stays an accepted transient
(an old server just skips the new read guard, no regression).

* fix(ec): fail the pre-encode sweep for any reachable node that can't ack teardown

A reachable pre-upgrade server ignores full_teardown and returns success
without wiping an orphan, which a later copy then folds into the new
generation. Treat a missing full_teardown_done ack as fatal for every
reachable node (best-effort only for a gRPC-unreachable one), not just for
topology-reported pairs.

* fix(ec): return the served shard identity and validate it client-side

The encode identity was only enforced server-side, so a pre-upgrade server
ignored the request field and served bytes unchecked. Echo the served
shard's EncodeTsNs on every read response chunk and have the client reject a
mismatch (including 0 from an old server), so the guard holds regardless of
server version; a rejected read recovers from parity.

* fix(ec): reject a short/empty remote shard read instead of serving zeros

doReadRemoteEcShardInterval accepted an immediate EOF or a short stream and
returned success with a partly zero-filled, unvalidated buffer (the server
stamps the identity only on chunks that carry bytes). A non-deleted interval
must arrive whole: require n == len(buf), exempting the is_deleted
short-circuit (n=0), matching readLocalEcShardInterval's local check. A short
read now fails so the caller recovers from parity.

* test(ec): fake volume server echoes the full_teardown acknowledgement

The worker now fails a teardown delete that isn't acknowledged (so a
pre-upgrade server can't silently skip the wipe). The fake server's no-op
VolumeEcShardsDelete returned an empty response, which the worker read as a
skipped teardown and aborted the encode. Echo full_teardown_done.

* feat(ec): mirror the encode-run identity guard + full_teardown into the Rust volume server

The Go volume server stamps an encode-run identity (encode_ts_ns) into the .vif
and rejects a read served from a shard of a different run; full_teardown wipes a
whole generation and acknowledges it. The Rust volume server had none of it.
Mirror the shared logic: load encode_ts_ns from the .vif onto the EcVolume,
stamp it on every read response, and reject a request/response mismatch on both
the server and the distributed-read client (recovering from parity); handle
full_teardown by evicting the volume and wiping every EC artifact on each disk,
echoing full_teardown_done so the caller can detect a server that ignored it.

* fix(ec): remove a stale .vif on full teardown of a shard-only node

A shard copy installs shards + .ecx before .vif, so an interrupted copy after a
teardown could mount the new files under the previous run's identity / version /
shard ratio / dat_file_size carried by the surviving .vif. Remove .vif during
full teardown, gated on .idx absence so a source-volume holder keeps its live
.vif. In Rust this lives in a teardown-only helper so the reconcile / load-
fallback paths (which share the base removal) still preserve .vif.

* fix(ec): treat a missing teardown ack as fatal, not as an unreachable node

isNodeUnreachable returned true for any non-gRPC-status error, so a reachable
pre-upgrade server's missing full_teardown_done ack (a plain error) was
classified unreachable and the unreported pair was silently skipped. Classify
only a real codes.Unavailable as unreachable, and wrap the missing ack in a
sentinel the sweep treats as fatal regardless. A genuinely down node still
surfaces as Unavailable from the RPC and stays best-effort.

* fix(ec): reject a short shard read in the local EC needle reader

read_ec_shard_needle ignored the byte count from shard.read_at and appended the
whole pre-sized buffer, so a truncated shard's zero-filled tail passed the later
length check and parsed as garbage. Require n == buf.len() per interval, erroring
on a short read like the local interval reader already does.

* fix(ec): probe reachability before skipping a node that returns Unavailable

The pre-encode sweep skipped any node whose teardown delete returned
codes.Unavailable, but a reachable volume server in maintenance mode also
returns that code for the maintenance-gated delete, so its stale EC files were
left behind on a node that can still receive the new generation. Confirm with a
non-maintenance-gated empty-target Ping: skip only when the node fails the probe
too (genuinely unreachable).

* fix(ec): use try_exists for the teardown .vif .idx guard

The teardown-only .vif removal gated on Path::exists(), which returns false on a
permission/IO stat error, so a stat failure on a present .idx would read as a
shard-only node and delete the live source volume's .vif. Gate on
try_exists() == Ok(false) instead, preserving the sidecar on any stat error.

* fix(ec): only skip a sweep node when a Ping confirms it is transport-down

The pre-encode sweep skipped a node whenever its teardown delete and a liveness
Ping both failed, but it treated ANY Ping error as down — an application-level
Internal/ResourceExhausted, or Unimplemented from a pre-Ping server, left a
reachable node's stale generation in place. Classify the Ping tri-state and skip
only when it transport-fails with codes.Unavailable; a reachable or inconclusive
node stays fatal.

* fix(ec): exclude sweep-skipped nodes from the encode's rebalance

The pre-encode sweep skips a genuinely-down node best-effort, but the rebalance
then recollected the current topology — a node that recovered between the two
could become a copy target and receive the new generation while still holding
its stale, never-cleared shards. Have the sweep return the skipped set and
exclude those nodes from the rebalance for this encode, so a node we could not
clean cannot receive the new generation. Standalone ec.balance is unaffected.

* fix(ec): re-sweep recovered nodes before generation so they aren't stranded

A node skipped as down by the pre-encode sweep is excluded from the rebalance,
but it can recover and become the generation host — mounting all shards locally,
then being excluded from distribution. Union-only verification accepts all
shards on one node and deletes the originals: a single point of failure. Re-sweep
the skipped nodes just before generation; one whose teardown now succeeds leaves
the skipped set and rebalances normally, while a node still down stays skipped.

* fix(ec): abort the encode if a selected source is still skipped after re-sweep

The re-sweep un-skips a recovered node, but the source was selected before it and
a node can stay down through the re-sweep then recover just in time to be the
generation host — mounting all shards locally while still excluded from the
rebalance, which union-only verification accepts before deleting the originals.
Abort the encode when a selected source remains skipped after the re-sweep.

* fix(ec): batch delete returns retriable 503 when a volume became EC mid-batch

If a volume is not EC at the batch-delete classification but is encoded to EC and
its .dat deleted before the regular-volume mutation, the mutation returns an exact
"not found" that the filer chunk-GC treats as completed, dropping the delete.
Recheck EC presence under the mutation lock and return a retriable 503 with the
"try again" token so the filer requeues it onto the EC path.

* fix(ec): recheck EC state before the regular batch-delete mutation

ec.encode mounts EC shards (copied from the .dat) before deleting the originals,
so a volume can be EC while its .dat still exists. The batch delete only rechecked
EC after a NotFound, so a successful regular-volume delete in that window wrote a
tombstone to the soon-removed .dat — the delete was lost and the needle resurrected
from the pre-tombstone shards. Recheck has_ec_volume under the write lock before
delete_volume_needle and return a retriable 503 so the filer requeues onto the EC path.

* fix(volume): make the metrics push test independent of test order

test_push_metrics_once asserted the pushed body contains the request-counter
family without ever touching the counter — a CounterVec with no children emits
nothing, so the assertion only held when another test had already created a
labelset in the shared registry. Create one in the test itself.
2026-06-10 22:31:18 -07:00
Chris Lu d51454adf4 rust(seaweed-volume): distributed EC read across peer servers (#9516)
* feat(seaweed-volume): distributed EC read across peer servers

EcVolume::read_ec_shard_needle previously errored with NotFound when
any interval's shard wasn't local. In an RS(10,4)-across-N deployment
each server holds one shard, so every read needed >=9 peer fetches and
post-EC GETs returned 404 on volumes whose shards lived on more than
one server.

Mirror of weed/storage/store_ec.go's readOneEcShardInterval ->
readRemoteEcShardInterval -> recoverOneRemoteEcShardInterval chain:

  * server/store_ec.rs (new): entry point
    read_ec_shard_needle_distributed. Snapshots locate-needle + local
    reads under the Store sync lock, drops the lock, then async-fetches
    missing intervals via the peer's VolumeEcShardRead RPC. Falls back
    to Reed-Solomon reconstruction (read every other shard at the same
    (shard_offset, size) and run rs.reconstruct) when the direct peer
    read fails. Refreshes the per-EcVolume shard_locations cache from
    the master's LookupEcVolume RPC using Go's freshness thresholds
    (11s / 7min / 37min).
  * erasure_coding/ec_volume.rs: shard_locations now sits behind a
    std::sync::RwLock so the read path can refresh the map without
    holding the Store write lock. Adds shard_locations_refresh_time
    (Mutex<Option<Instant>>) for the staleness heuristic. Mirrors Go's
    ShardLocationsLock / ShardLocationsRefreshTime fields. set/get
    helpers updated for interior mutability.
  * server/handlers.rs: GET handler now tries the local-only fast
    path first, then falls through to the distributed path on
    NotFound.

* review: address PR 9516 feedback on distributed EC read

Five of the six PR-review comments addressed; the sixth (JWT on
outgoing peer gRPC) is deferred with an explicit TODO because the
crate-wide outgoing-JWT signing surface doesn't exist yet — adding it
in this one call site would split the credential plumbing across
peer paths that already lack it (copy_file_from_source, batch_delete,
…). Revisit when an outgoing-JWT helper lands.

Fixed in this commit:

  * Handlers: drop the two-tier (local-first, then distributed)
    read in handlers.rs. read_ec_shard_needle_distributed already
    does the local-first pass under the same store read lock; the
    redundant outer attempt re-read local intervals twice for any
    needle that spanned mixed-locality shards.
  * Scanner snapshot: replace inline locate-needle math with
    `ecv.locate_needle(needle_id)`. Same routine the local-only
    read path uses, so byte-identical on shard-size + interval
    boundaries.
  * EcVolume::set_shard_locations also advances
    shard_locations_refresh_time so the staleness check honors
    callers that populate the cache directly without going through
    the master LookupEcVolume RPC.
  * parse_grpc_address moved from grpc_server.rs into
    grpc_client.rs as `pub` and is reused by both grpc_server.rs
    and the new store_ec module. Single source of truth for the
    HTTP↔gRPC port-offset convention.
  * Reconstruction (recover_one_remote_ec_shard_interval) now seeds
    bufs from locally-mounted survivor shards BEFORE the remote
    fan-out. Previously the fan-out was remote-only, so when the
    shard_locations cache was cold or the master lookup failed,
    reconstruction errored even though enough siblings were on
    local disk to recover the missing interval.

* review: tighten parse_grpc_address; atomic shard-locations cache swap

Two follow-up findings from the PR 9516 review round 2:

  * `parse_grpc_address` now validates BOTH port components in the
    dotted form (`host:port.grpcPort`) — previously a non-numeric
    HTTP port like `host:abc.18080` slipped through and tripped a
    less-useful downstream URI parse error. The implicit form
    (`host:port` → port + 10000) also gains an overflow check so
    inputs like `host:60000` (which silently wrap past u16) are
    rejected here instead of producing an opaque connection
    failure later. Six unit tests cover each rejection path.

  * `EcVolume::set_shard_locations` no longer bumps the per-volume
    refresh timestamp. The previous fix introduced a freshness
    race: a multi-shard population that inserts shard-by-shard
    would flip `needs_refresh == false` on the first write, letting
    a concurrent reader observe a half-populated map already
    marked "fresh" and return NotFound for the not-yet-inserted
    shards. Added `EcVolume::replace_shard_locations(map)` for the
    atomic bulk swap; `write_back_shard_locations` in the
    distributed-read path uses it so the cache transitions
    old → fresh in a single observable step.
2026-05-16 20:44:28 -07:00