// erasureObjects - Implements ER object layer.
type erasureObjects struct {
	setDriveCount      int
	defaultParityCount int

	setIndex  int
	poolIndex int

	// getDisks returns list of storageAPIs.
	getDisks func() []StorageAPI

	// getLockers returns list of remote and local lockers.
	getLockers func() ([]dsync.NetLocker, string)

	// getEndpoints returns list of endpoint belonging this set.

	testShuffleDisks(t, z)
}

// Test shuffleDisks which returns shuffled slice of disks for their actual distribution.
func testShuffleDisks(t *testing.T, z *erasureServerPools) {
	disks := z.serverPools[0].GetDisks(0)()
	distribution := []int{16, 14, 12, 10, 8, 6, 4, 2, 1, 3, 5, 7, 9, 11, 13, 15}
	shuffledDisks := shuffleDisks(disks, distribution)
	// From the "distribution" above you can notice that:

		copy(eps, s.endpoints.Endpoints[setIndex*s.setDriveCount:setIndex*s.setDriveCount+s.setDriveCount])
		return eps
	}
}

// GetDisks returns a closure for a given set, which provides list of disks per set.
func (s *erasureSets) GetDisks(setIndex int) func() []StorageAPI {
	return func() []StorageAPI {
		s.erasureDisksMu.RLock()
		defer s.erasureDisksMu.RUnlock()

	CompleteMultipartUpload(ctx context.Context, bucket, object, uploadID string, uploadedParts []CompletePart, opts ObjectOptions) (objInfo ObjectInfo, err error)

	GetDisks(poolIdx, setIdx int) ([]StorageAPI, error) // return the disks belonging to pool and set.
	SetDriveCounts() []int                              // list of erasure stripe size for each pool in order.

	// Healing operations.

	if err != nil {
		t.Fatal(err)
	}

	erasureDisks := xl.getDisks()
	z.serverPools[0].erasureDisksMu.Lock()
	xl.getDisks = func() []StorageAPI {
		for i := range erasureDisks[:6] {
			erasureDisks[i] = newNaughtyDisk(erasureDisks[i], nil, errFaultyDisk)
		}
		return erasureDisks
	}

	// Simulate read quorum failure by taking enough disks offline
	// With 16 disks (EC 8+8), read quorum is 9. Taking 8 disks offline leaves only 8,
	// which is below read quorum.
	erasureDisks := xl.getDisks()
	z.serverPools[0].erasureDisksMu.Lock()
	xl.getDisks = func() []StorageAPI {
		for i := range erasureDisks[:8] {
			erasureDisks[i] = nil
		}
		return erasureDisks
	}
	z.serverPools[0].erasureDisksMu.Unlock()

		return disk
	}

	// Remove 4 disks.
	setDisks(nil, nil, nil, nil)

	// Create delete marker under quorum.
	objInfo, err := objLayer.DeleteObject(ctx, bucket, object, ObjectOptions{Versioned: true})
	if err != nil {
		t.Fatal(err)
	}

	// Restore...
	setDisks(orgDisks[:4]...)

package cmd

import (
	"context"
	"math/rand"
	"sync"
	"time"
)

func (er erasureObjects) getOnlineDisks() (newDisks []StorageAPI) {
	disks := er.getDisks()
	var wg sync.WaitGroup
	var mu sync.Mutex
	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	for _, i := range r.Perm(len(disks)) {
		wg.Add(1)
		go func() {
			defer wg.Done()
			if disks[i] == nil {

	defer func() {
		if errors.Is(err, errFileNotFound) {
			err = errUploadIDNotFound
		}
	}()

	uploadIDPath := er.getUploadIDDir(bucket, object, uploadID)

	storageDisks := er.getDisks()

	// Read metadata associated with the object from all disks.
	partsMetadata, errs := readAllFileInfo(ctx, storageDisks, bucket, minioMetaMultipartBucket,
		uploadIDPath, "", false, false)

		}

		// All operations are performed without locks, so we must be careful and allow for failures.
		// Read metadata associated with the object from a disk.
		if retries > 0 {
			for _, disk := range er.getDisks() {
				if disk == nil {
					continue
				}
				if !disk.IsOnline() {
					continue
				}
				_, err := disk.ReadVersion(ctx, "", minioMetaBucket,
					o.objectPath(0), "", ReadOptions{})