// max requests per node is calculated as
		// total_ram / ram_per_request
		blockSize := xioutil.LargeBlock + xioutil.SmallBlock
		if legacy {
			// ram_per_request is (1MiB+32KiB) * driveCount \
			//    + 2 * 10MiB (default erasure block size v1) + 2 * 1MiB (default erasure block size v2)
			apiRequestsMaxPerNode = int(maxMem / uint64(maxSetDrives*blockSize+int(blockSizeV1*2+blockSizeV2*2)))
		} else {

			buffer = make([]byte, fi.Erasure.BlockSize, 2*fi.Erasure.BlockSize)
		} else {
			buffer = globalBytePoolCap.Load().Get()
			defer globalBytePoolCap.Load().Put(buffer)
		}
	case size < fi.Erasure.BlockSize:
		// No need to allocate fully fi.Erasure.BlockSize buffer if the incoming data is smaller.
		buffer = make([]byte, size, 2*size+int64(fi.Erasure.ParityBlocks+fi.Erasure.DataBlocks-1))
	}

const blockSize = 8 << 10 // 8192

// By default at least 128 entries in single getdents call (1MiB buffer)
var (
	direntPool = bpool.Pool[*[]byte]{
		New: func() *[]byte {
			buf := make([]byte, blockSize*128)
			return &buf
		},
	}

	direntNamePool = bpool.Pool[*[]byte]{
		New: func() *[]byte {
			buf := make([]byte, blockSize)
			return &buf
		},
	}
)

func (fi FileInfo) shardSize() int64 {
	return ceilFrac(fi.Erasure.BlockSize, int64(fi.Erasure.DataBlocks))
}

// ShardFileSize - returns final erasure size from original size.
func (fi FileInfo) ShardFileSize(totalLength int64) int64 {
	if totalLength == 0 {
		return 0
	}
	if totalLength == -1 {
		return -1
	}
	numShards := totalLength / fi.Erasure.BlockSize
	lastBlockSize := totalLength % fi.Erasure.BlockSize

		Size:             0,
		Mode:             0,
		Metadata:         nil,
		Parts:            nil,
		Erasure: ErasureInfo{
			Algorithm:    ReedSolomon.String(),
			DataBlocks:   4,
			ParityBlocks: 2,
			BlockSize:    10000,
			Index:        1,
			Distribution: []int{1, 2, 3, 4, 5, 6, 7, 8},
			Checksums: []ChecksumInfo{{
				PartNumber: 1,
				Algorithm:  HighwayHash256S,
				Hash:       nil,
			}},
		},

	if totalLength == -1 {
		return -1
	}
	numShards := totalLength / e.BlockSize
	lastBlockSize := totalLength % e.BlockSize
	lastShardSize := ceilFrac(lastBlockSize, int64(e.DataBlocks))
	return numShards*e.ShardSize() + lastShardSize
}

// ShardSize - returns actual shared size from erasure blockSize.
func (e ErasureInfo) ShardSize() int64 {
	return ceilFrac(e.BlockSize, int64(e.DataBlocks))
}

package cmd

import (
	"sync"

	"github.com/dustin/go-humanize"
)

const (
	// Block size used for all internal operations version 1.

	// TLDR..
	// Not used anymore xl.meta captures the right blockSize
	// so blockSizeV2 should be used for all future purposes.
	// this value is kept here to calculate the max API
	// requests based on RAM size for existing content.
	blockSizeV1 = 10 * humanize.MiByte

	case size == 0:
		buffer = make([]byte, 1) // Allocate at least a byte to reach EOF
	case size >= fi.Erasure.BlockSize:
		buffer = globalBytePoolCap.Load().Get()
		defer globalBytePoolCap.Load().Put(buffer)
	case size < fi.Erasure.BlockSize:
		// No need to allocate fully blockSizeV1 buffer if the incoming data is smaller.
		buffer = make([]byte, size, 2*size+int64(fi.Erasure.ParityBlocks+fi.Erasure.DataBlocks-1))
	}

		Size:             0,
		Mode:             0,
		Metadata:         nil,
		Parts:            nil,
		Erasure: ErasureInfo{
			Algorithm:    ReedSolomon.String(),
			DataBlocks:   4,
			ParityBlocks: 2,
			BlockSize:    10000,
			Index:        1,
			Distribution: []int{1, 2, 3, 4, 5, 6, 7, 8},
			Checksums: []ChecksumInfo{{
				PartNumber: 1,
				Algorithm:  HighwayHash256S,
				Hash:       nil,
			}},
		},

func shardSize(blockSize, dataBlocks int) (sz int) {
	if dataBlocks == 0 {
		// do nothing on invalid input
		return sz
	}
	// Make denominator positive
	if dataBlocks < 0 {
		blockSize = -blockSize
		dataBlocks = -dataBlocks
	}
	sz = blockSize / dataBlocks
	if blockSize > 0 && blockSize%dataBlocks != 0 {
		sz++
	}
	return sz
}