Support bucket versioning (#9377)

- Implement a new xl.json 2.0.0 format to support,
  this moves the entire marshaling logic to POSIX
  layer, top layer always consumes a common FileInfo
  construct which simplifies the metadata reads.
- Implement list object versions
- Migrate to siphash from crchash for new deployments
  for object placements.

Fixes #2111

cmd/erasure-coding.go

@@ -0,0 +1,143 @@
+/*
+ * MinIO Cloud Storage, (C) 2017 MinIO, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package cmd
+
+import (
+	"context"
+	"sync"
+
+	"github.com/klauspost/reedsolomon"
+	"github.com/minio/minio/cmd/logger"
+)
+
+// Erasure - erasure encoding details.
+type Erasure struct {
+	encoder                  func() reedsolomon.Encoder
+	dataBlocks, parityBlocks int
+	blockSize                int64
+}
+
+// NewErasure creates a new ErasureStorage.
+func NewErasure(ctx context.Context, dataBlocks, parityBlocks int, blockSize int64) (e Erasure, err error) {
+	// Check the parameters for sanity now.
+	if dataBlocks <= 0 || parityBlocks <= 0 {
+		return e, reedsolomon.ErrInvShardNum
+	}
+
+	if dataBlocks+parityBlocks > 256 {
+		return e, reedsolomon.ErrMaxShardNum
+	}
+
+	e = Erasure{
+		dataBlocks:   dataBlocks,
+		parityBlocks: parityBlocks,
+		blockSize:    blockSize,
+	}
+
+	// Encoder when needed.
+	var enc reedsolomon.Encoder
+	var once sync.Once
+	e.encoder = func() reedsolomon.Encoder {
+		once.Do(func() {
+			e, err := reedsolomon.New(dataBlocks, parityBlocks, reedsolomon.WithAutoGoroutines(int(e.ShardSize())))
+			if err != nil {
+				// Error conditions should be checked above.
+				panic(err)
+			}
+			enc = e
+		})
+		return enc
+	}
+	return
+}
+
+// EncodeData encodes the given data and returns the erasure-coded data.
+// It returns an error if the erasure coding failed.
+func (e *Erasure) EncodeData(ctx context.Context, data []byte) ([][]byte, error) {
+	if len(data) == 0 {
+		return make([][]byte, e.dataBlocks+e.parityBlocks), nil
+	}
+	encoded, err := e.encoder().Split(data)
+	if err != nil {
+		logger.LogIf(ctx, err)
+		return nil, err
+	}
+	if err = e.encoder().Encode(encoded); err != nil {
+		logger.LogIf(ctx, err)
+		return nil, err
+	}
+	return encoded, nil
+}
+
+// DecodeDataBlocks decodes the given erasure-coded data.
+// It only decodes the data blocks but does not verify them.
+// It returns an error if the decoding failed.
+func (e *Erasure) DecodeDataBlocks(data [][]byte) error {
+	var isZero = 0
+	for _, b := range data[:] {
+		if len(b) == 0 {
+			isZero++
+			break
+		}
+	}
+	if isZero == 0 || isZero == len(data) {
+		// If all are zero, payload is 0 bytes.
+		return nil
+	}
+	return e.encoder().ReconstructData(data)
+}
+
+// DecodeDataAndParityBlocks decodes the given erasure-coded data and verifies it.
+// It returns an error if the decoding failed.
+func (e *Erasure) DecodeDataAndParityBlocks(ctx context.Context, data [][]byte) error {
+	if err := e.encoder().Reconstruct(data); err != nil {
+		logger.LogIf(ctx, err)
+		return err
+	}
+	return nil
+}
+
+// ShardSize - returns actual shared size from erasure blockSize.
+func (e *Erasure) ShardSize() int64 {
+	return ceilFrac(e.blockSize, int64(e.dataBlocks))
+}
+
+// ShardFileSize - returns final erasure size from original size.
+func (e *Erasure) ShardFileSize(totalLength int64) int64 {
+	if totalLength == 0 {
+		return 0
+	}
+	if totalLength == -1 {
+		return -1
+	}
+	numShards := totalLength / e.blockSize
+	lastBlockSize := totalLength % int64(e.blockSize)
+	lastShardSize := ceilFrac(lastBlockSize, int64(e.dataBlocks))
+	return numShards*e.ShardSize() + lastShardSize
+}
+
+// ShardFileOffset - returns the effective offset where erasure reading begins.
+func (e *Erasure) ShardFileOffset(startOffset, length, totalLength int64) int64 {
+	shardSize := e.ShardSize()
+	shardFileSize := e.ShardFileSize(totalLength)
+	endShard := (startOffset + int64(length)) / e.blockSize
+	tillOffset := endShard*shardSize + shardSize
+	if tillOffset > shardFileSize {
+		tillOffset = shardFileSize
+	}
+	return tillOffset
+}