XL: Format heal should re-allocate new UUIDs not reuse. (#1953)

This patch also supports writing to a temporary file and renaming
rather than appending to an existing file. This helps in avoiding
inconsistent files.
master
Harshavardhana 9 years ago committed by Anand Babu (AB) Periasamy
parent e10934a88e
commit f4830162a4
  1. 242
      format-config-v1.go
  2. 5
      xl-v1.go

@ -22,8 +22,6 @@ import (
"fmt"
"strings"
"sync"
"github.com/skyrings/skyring-common/tools/uuid"
)
// fsFormat - structure holding 'fs' format.
@ -107,9 +105,15 @@ else // No healing at this point forward, some disks are offline or dead.
fi
*/
// error returned when some disks are found to be unformatted.
var errSomeDiskUnformatted = errors.New("some disks are found to be unformatted")
// error returned when some disks are offline.
var errSomeDiskOffline = errors.New("some disks are offline")
// errDiskOrderMismatch - returned when disk UUID is not in consistent JBOD order.
var errDiskOrderMismatch = errors.New("disk order mismatch")
// Returns error slice into understandable errors.
func reduceFormatErrs(errs []error, diskCount int) error {
var errUnformattedDiskCount = 0
@ -224,9 +228,6 @@ func genericFormatCheck(formatConfigs []*formatConfigV1, sErrs []error) (err err
return nil
}
// errDiskOrderMismatch - returned when disk UUID is not in consistent JBOD order.
var errDiskOrderMismatch = errors.New("disk order mismatch")
// isSavedUUIDInOrder - validates if disk uuid is present and valid in all
// available format config JBOD. This function also validates if the disk UUID
// is always available on all JBOD under the same order.
@ -343,7 +344,7 @@ func reorderDisks(bootstrapDisks []StorageAPI, formatConfigs []*formatConfigV1)
return newDisks, nil
}
// loadFormat - load format from disk.
// loadFormat - loads format.json from disk.
func loadFormat(disk StorageAPI) (format *formatConfigV1, err error) {
var buffer []byte
buffer, err = readAll(disk, minioMetaBucket, formatConfigFile)
@ -373,23 +374,43 @@ func loadFormat(disk StorageAPI) (format *formatConfigV1, err error) {
return format, nil
}
// isFormatNotFound - returns true if all `format.json` are not
// found on all disks.
func isFormatNotFound(formats []*formatConfigV1) bool {
for _, format := range formats {
// One of the `format.json` is found.
if format != nil {
return false
}
}
// All format.json missing, success.
return true
}
// isFormatFound - returns true if all input formats are found on
// all disks.
func isFormatFound(formats []*formatConfigV1) bool {
for _, format := range formats {
// One of `format.json` is not found.
if format == nil {
return false
}
}
// All format.json present, success.
return true
}
// Heals any missing format.json on the drives. Returns error only for unexpected errors
// as regular errors can be ignored since there might be enough quorum to be operational.
func healFormatXL(bootstrapDisks []StorageAPI) error {
needHeal := make([]bool, len(bootstrapDisks)) // Slice indicating which drives needs healing.
formatConfigs := make([]*formatConfigV1, len(bootstrapDisks))
func healFormatXL(storageDisks []StorageAPI) error {
formatConfigs := make([]*formatConfigV1, len(storageDisks))
var referenceConfig *formatConfigV1
successCount := 0 // Tracks if we have successfully loaded all `format.json` from all disks.
formatNotFoundCount := 0 // Tracks if we `format.json` is not found on all disks.
// Loads `format.json` from all disks.
for index, disk := range bootstrapDisks {
for index, disk := range storageDisks {
formatXL, err := loadFormat(disk)
if err != nil {
if err == errUnformattedDisk {
// format.json is missing, should be healed.
needHeal[index] = true
formatNotFoundCount++
continue
} else if err == errDiskNotFound { // Is a valid case we
// can proceed without healing.
@ -399,16 +420,15 @@ func healFormatXL(bootstrapDisks []StorageAPI) error {
return err
} // Success.
formatConfigs[index] = formatXL
successCount++
}
// All `format.json` has been read successfully, previously completed.
if successCount == len(bootstrapDisks) {
if isFormatFound(formatConfigs) {
// Return success.
return nil
}
// All disks are fresh, format.json will be written by initFormatXL()
if formatNotFoundCount == len(bootstrapDisks) {
return initFormatXL(bootstrapDisks)
if isFormatNotFound(formatConfigs) {
return initFormatXL(storageDisks)
}
// Validate format configs for consistency in JBOD and disks.
if err := checkFormatXL(formatConfigs); err != nil {
@ -426,68 +446,40 @@ func healFormatXL(bootstrapDisks []StorageAPI) error {
}
}
uuidUsage := make([]struct {
uuid string // Disk uuid
inUse bool // indicates if the uuid is used by
// any disk
}, len(bootstrapDisks))
// Returns any unused drive UUID.
getUnusedUUID := func() string {
for index := range uuidUsage {
if !uuidUsage[index].inUse {
uuidUsage[index].inUse = true
return uuidUsage[index].uuid
}
}
return ""
}
// Collect new format configs.
var newFormatConfigs = make([]*formatConfigV1, len(storageDisks))
// From reference config update UUID's not be in use.
for index, diskUUID := range referenceConfig.XL.JBOD {
uuidUsage[index].uuid = diskUUID
uuidUsage[index].inUse = false
}
// Collect new JBOD.
newJBOD := referenceConfig.XL.JBOD
// For all config formats validate if they are in use and
// update the uuidUsage values.
for _, config := range formatConfigs {
if config == nil {
continue
}
for index := range uuidUsage {
if config.XL.Disk == uuidUsage[index].uuid {
uuidUsage[index].inUse = true
break
}
}
}
// This section heals the format.json and updates the fresh disks
// by apply a new UUID for all the fresh disks.
for index, heal := range needHeal {
if !heal {
continue
}
config := &formatConfigV1{}
*config = *referenceConfig
config.XL.Disk = getUnusedUUID()
if config.XL.Disk == "" {
// getUnusedUUID() should have
// returned an unused uuid, it
// is an unexpected error.
return errUnexpected
for index, format := range formatConfigs {
if format == nil {
newJBOD[index] = getUUID()
}
formatBytes, err := json.Marshal(config)
if err != nil {
return err
}
// Collect new format configs that need to be written.
for index, format := range formatConfigs {
if format == nil {
config := &formatConfigV1{
Version: referenceConfig.Version,
Format: referenceConfig.Format,
XL: &xlFormat{
Version: referenceConfig.XL.Version,
Disk: newJBOD[index],
JBOD: newJBOD,
},
}
newFormatConfigs[index] = config
continue
}
// Fresh disk without format.json
_ = bootstrapDisks[index].AppendFile(minioMetaBucket, formatConfigFile, formatBytes)
// Ignore any error from AppendFile() as
// quorum might still be there to be operational.
newFormatConfigs[index] = format
newFormatConfigs[index].XL.JBOD = newJBOD
newFormatConfigs[index].XL.Disk = newJBOD[index]
}
return nil
// Save new `format.json` across all disks.
return saveFormatXL(storageDisks, newFormatConfigs)
}
// loadFormatXL - loads XL `format.json` and returns back properly
@ -561,53 +553,91 @@ func checkFormatXL(formatConfigs []*formatConfigV1) error {
return checkDisksConsistency(formatConfigs)
}
// initFormatXL - save XL format configuration on all disks.
func initFormatXL(storageDisks []StorageAPI) (err error) {
var (
jbod = make([]string, len(storageDisks))
formats = make([]*formatConfigV1, len(storageDisks))
saveFormatErrCnt = 0
)
// saveFormatXL - populates `format.json` on disks in its order.
func saveFormatXL(storageDisks []StorageAPI, formats []*formatConfigV1) error {
var errs = make([]error, len(storageDisks))
var wg = &sync.WaitGroup{}
// Write `format.json` to all disks.
for index, disk := range storageDisks {
if err = disk.MakeVol(minioMetaBucket); err != nil {
if err != errVolumeExists {
saveFormatErrCnt++
// Check for write quorum.
if saveFormatErrCnt <= len(storageDisks)-(len(storageDisks)/2+3) {
continue
}
return errXLWriteQuorum
}
if disk == nil {
continue
}
var u *uuid.UUID
u, err = uuid.New()
if err != nil {
saveFormatErrCnt++
// Check for write quorum.
if saveFormatErrCnt <= len(storageDisks)-(len(storageDisks)/2+3) {
continue
wg.Add(1)
go func(index int, disk StorageAPI, format *formatConfigV1) {
defer wg.Done()
// Marshal and write to disk.
formatBytes, err := json.Marshal(format)
if err != nil {
errs[index] = err
return
}
// Purge any existing temporary file, okay to ignore errors here.
disk.DeleteFile(minioMetaBucket, formatConfigFileTmp)
// Append file `format.json.tmp`.
if err = disk.AppendFile(minioMetaBucket, formatConfigFileTmp, formatBytes); err != nil {
errs[index] = err
return
}
// Rename file `format.json.tmp` --> `format.json`.
if err = disk.RenameFile(minioMetaBucket, formatConfigFileTmp, minioMetaBucket, formatConfigFile); err != nil {
errs[index] = err
return
}
}(index, disk, formats[index])
}
// Wait for the routines to finish.
wg.Wait()
// Validate if we encountered any errors, return quickly.
for _, err := range errs {
if err != nil {
// Failure.
return err
}
}
// Success.
return nil
}
// initFormatXL - save XL format configuration on all disks.
func initFormatXL(storageDisks []StorageAPI) (err error) {
// Initialize jbods.
var jbod = make([]string, len(storageDisks))
// Initialize formats.
var formats = make([]*formatConfigV1, len(storageDisks))
// Initialize `format.json`.
for index, disk := range storageDisks {
if disk == nil {
continue
}
// Allocate format config.
formats[index] = &formatConfigV1{
Version: "1",
Format: "xl",
XL: &xlFormat{
Version: "1",
Disk: u.String(),
Disk: getUUID(),
},
}
jbod[index] = formats[index].XL.Disk
}
// Update the jbod entries.
for index, disk := range storageDisks {
formats[index].XL.JBOD = jbod
formatBytes, err := json.Marshal(formats[index])
if err != nil {
return err
}
if err = disk.AppendFile(minioMetaBucket, formatConfigFile, formatBytes); err != nil {
return err
if disk == nil {
continue
}
// Save jbod.
formats[index].XL.JBOD = jbod
}
return nil
// Save formats `format.json` across all disks.
return saveFormatXL(storageDisks, formats)
}

@ -28,8 +28,13 @@ import (
const (
// Format config file carries backend format specific details.
formatConfigFile = "format.json"
// Format config tmp file carries backend format.
formatConfigFileTmp = "format.json.tmp"
// XL metadata file carries per object metadata.
xlMetaJSONFile = "xl.json"
// Uploads metadata file carries per multipart object metadata.
uploadsJSONFile = "uploads.json"
)

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