The V1 header wire format has no Signature field, so decoding into a
reused header leaked the previous object's signature. Reset it along
with EcN/EcM so a decode fully replaces the header contents.
Signed-off-by: Julien Laurenceau <julien.laurenceau@pepitedata.com>
The legacy header decode paths zeroed EcN twice (z.EcN, z.EcN = 0, 0)
instead of EcN and EcM, so EcM retained its previous value when the
same structure was reused across decodes. Decoding an xl.meta written
by an older release would then leak the erasure metadata (data/parity
block counts) of a previously decoded object into it, potentially
corrupting quorum and healing decisions.
Also zero the fields on the V1 header path, which had no reset at
all.
Signed-off-by: Julien Laurenceau <julien.laurenceau@pepitedata.com>
Standardize the related SILO components on Go 1.27 tooling, etcd 3.7.1, current Go-maintained modules, shared runtime versions, and explicit security and portability pins.
Keep the shared package Go 1.26 consumer floor, isolate lint tooling from product dependency selection, and preserve upstream-compatible import paths.
Keep the EC in header, so it can be retrieved easily for dynamic quorum calculations.
To not force a full metadata decode on every read the value will be 0/0 for data written in previous versions.
Size is expected to increase by 2 bytes per version, since all valid values can be represented with 1 byte each.
Example:
```
λ xl-meta xl.meta
{
"Versions": [
{
"Header": {
"EcM": 4,
"EcN": 8,
"Flags": 6,
"ModTime": "2024-04-17T11:46:25.325613+02:00",
"Signature": "0a409875",
"Type": 1,
"VersionID": "8e03504e11234957b2727bc53eda0d55"
},
...
```
Not used for operations yet.
When calculating signatures empty part ETags were not discarded, leading
to a different signature compared to freshly created ones.
This would mean that after a heal signature of the healed metadata would be
different. Fixing the calculation of signature will make these consistent.
Furthermore when inconsistent entries, with zero version ID, with the same
mod times but different signatures, the one with the lowest signature would
be picked for quorum check. Since this is 50/50, we fall back to a simple
quorum count on all signatures.
Each of these fixes by themselves will lead to quorum. Tests were added
for regressions and expected outcomes.
Existing:
```go
type xlMetaV2 struct {
Versions []xlMetaV2Version `json:"Versions" msg:"Versions"`
}
```
Serialized as regular MessagePack.
```go
//msgp:tuple xlMetaV2VersionHeader
type xlMetaV2VersionHeader struct {
VersionID [16]byte
ModTime int64
Type VersionType
Flags xlFlags
}
```
Serialize as streaming MessagePack, format:
```
int(headerVersion)
int(xlmetaVersion)
int(nVersions)
for each version {
binary blob, xlMetaV2VersionHeader, serialized
binary blob, xlMetaV2Version, serialized.
}
```
xlMetaV2VersionHeader is <= 30 bytes serialized. Deserialized struct
can easily be reused and does not contain pointers, so efficient as a
slice (single allocation)
This allows quickly parsing everything as slices of bytes (no copy).
Versions are always *saved* sorted by modTime, newest *first*.
No more need to sort on load.
* Allows checking if a version exists.
* Allows reading single version without unmarshal all.
* Allows reading latest version of type without unmarshal all.
* Allows reading latest version without unmarshal of all.
* Allows checking if the latest is deleteMarker by reading first entry.
* Allows adding/updating/deleting a version with only header deserialization.
* Reduces allocations on conversion to FileInfo(s).
Julien Laurenceau