Add partial shard reconstruction
* Add partial shard reconstruction
* Fix padding causing the last shard to be rejected
* Add md5 checks on single parts
* Move md5 verified to `verified/filename.ext`
* Move complete (without md5) to `complete/filename.ext.partno`
It's not pretty, but at least now the md5 gives some confidence it works correctly.
Add combination of multiple parts.
Parts will be reconstructed and saved separately and can manually be combined to the complete object.
Parts will be named `(version_id)-(filename).(partnum).(in)complete`.
Adds `-xver` which can be used with `-export` and `-combine` to attempt to combine files across versions if data is suspected to be the same. Overlapping data is compared.
Bonus: Make `inspect` accept wildcards.
When inspecting files like `.minio.sys/pool.bin` that may be present on multiple sets, use signature to separate them.
Also fixes null versions to actually be useful with `-export -combine`.
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.
Will combine or write partial data of each version found in the inspect data.
Example:
```
> xl-meta -export -combine inspect-data.1228fb52.zip
(... metadata json...)
}
Attempting to combine version "994f1113-da94-4be1-8551-9dbc54b204bc".
Read shard 1 Data shards 9 Parity 4 (994f1113-da94-4be1-8551-9dbc54b204bc/shard-01-of-13.data)
Read shard 2 Data shards 9 Parity 4 (994f1113-da94-4be1-8551-9dbc54b204bc/shard-02-of-13.data)
Read shard 3 Data shards 9 Parity 4 (994f1113-da94-4be1-8551-9dbc54b204bc/shard-03-of-13.data)
Read shard 4 Data shards 9 Parity 4 (994f1113-da94-4be1-8551-9dbc54b204bc/shard-04-of-13.data)
Read shard 6 Data shards 9 Parity 4 (994f1113-da94-4be1-8551-9dbc54b204bc/shard-06-of-13.data)
Read shard 7 Data shards 9 Parity 4 (994f1113-da94-4be1-8551-9dbc54b204bc/shard-07-of-13.data)
Read shard 8 Data shards 8 Parity 5 (994f1113-da94-4be1-8551-9dbc54b204bc/shard-08-of-13.data)
Read shard 9 Data shards 8 Parity 5 (994f1113-da94-4be1-8551-9dbc54b204bc/shard-09-of-13.data)
Read shard 10 Data shards 8 Parity 5 (994f1113-da94-4be1-8551-9dbc54b204bc/shard-10-of-13.data)
Read shard 11 Data shards 8 Parity 5 (994f1113-da94-4be1-8551-9dbc54b204bc/shard-11-of-13.data)
Read shard 13 Data shards 8 Parity 5 (994f1113-da94-4be1-8551-9dbc54b204bc/shard-13-of-13.data)
Attempting to reconstruct using parity sets:
* Setup: Data shards: 9 - Parity blocks: 6
Have 6 complete remapped data shards and 6 complete parity shards. Could NOT reconstruct: too few shards given
* Setup: Data shards: 8 - Parity blocks: 5
Have 5 complete remapped data shards and 5 complete parity shards. Could reconstruct completely
0 bytes missing. Truncating 0 from the end.
Wrote output to 994f1113-da94-4be1-8551-9dbc54b204bc.complete
```
So far only inline data, but no real reason that external data can't also be included with some handling of blocks.
Supports only unencrypted data.
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).
