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minio/cmd/xl-v1-healing.go

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/*
* Minio Cloud Storage, (C) 2016 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 (
"fmt"
"path"
"sort"
"sync"
"github.com/minio/minio/pkg/errors"
)
// healFormatXL - heals missing `format.json` on freshly or corrupted
// disks (missing format.json but does have erasure coded data in it).
func healFormatXL(storageDisks []StorageAPI) (err error) {
// Attempt to load all `format.json`.
formatConfigs, sErrs := loadAllFormats(storageDisks)
// Generic format check.
// - if (no quorum) return error
// - if (disks not recognized) // Always error.
if err = genericFormatCheckXL(formatConfigs, sErrs); err != nil {
return err
}
numDisks := len(storageDisks)
_, unformattedDiskCount, diskNotFoundCount,
corruptedFormatCount, otherErrCount := formatErrsSummary(sErrs)
switch {
case unformattedDiskCount == numDisks:
// all unformatted.
if err = initFormatXL(storageDisks); err != nil {
return err
}
case diskNotFoundCount > 0:
return fmt.Errorf("cannot proceed with heal as %s",
errSomeDiskOffline)
case otherErrCount > 0:
return fmt.Errorf("cannot proceed with heal as some disks had unhandled errors")
case corruptedFormatCount > 0:
if err = healFormatXLCorruptedDisks(storageDisks, formatConfigs); err != nil {
return fmt.Errorf("Unable to repair corrupted format, %s", err)
}
case unformattedDiskCount > 0:
// All drives online but some report missing format.json.
if err = healFormatXLFreshDisks(storageDisks, formatConfigs); err != nil {
// There was an unexpected unrecoverable error
// during healing.
return fmt.Errorf("Unable to heal backend %s", err)
}
}
return nil
}
// Heals a bucket if it doesn't exist on one of the disks, additionally
// also heals the missing entries for bucket metadata files
// `policy.json, notification.xml, listeners.json`.
func (xl xlObjects) HealBucket(bucket string) error {
if err := checkBucketExist(bucket, xl); err != nil {
return err
}
// get write quorum for an object
writeQuorum := len(xl.storageDisks)/2 + 1
// Heal bucket.
if err := healBucket(xl.storageDisks, bucket, writeQuorum); err != nil {
return err
}
// Proceed to heal bucket metadata.
return healBucketMetadata(xl, bucket)
}
// Heal bucket - create buckets on disks where it does not exist.
func healBucket(storageDisks []StorageAPI, bucket string, writeQuorum int) error {
bucketLock := globalNSMutex.NewNSLock(bucket, "")
if err := bucketLock.GetLock(globalHealingTimeout); err != nil {
return err
}
defer bucketLock.Unlock()
// Initialize sync waitgroup.
var wg = &sync.WaitGroup{}
// Initialize list of errors.
var dErrs = make([]error, len(storageDisks))
// Make a volume entry on all underlying storage disks.
for index, disk := range storageDisks {
if disk == nil {
dErrs[index] = errors.Trace(errDiskNotFound)
continue
}
wg.Add(1)
// Make a volume inside a go-routine.
go func(index int, disk StorageAPI) {
defer wg.Done()
if _, err := disk.StatVol(bucket); err != nil {
if err != errVolumeNotFound {
dErrs[index] = errors.Trace(err)
return
}
if err = disk.MakeVol(bucket); err != nil {
dErrs[index] = errors.Trace(err)
}
}
}(index, disk)
}
// Wait for all make vol to finish.
wg.Wait()
reducedErr := reduceWriteQuorumErrs(dErrs, bucketOpIgnoredErrs, writeQuorum)
if errors.Cause(reducedErr) == errXLWriteQuorum {
// Purge successfully created buckets if we don't have writeQuorum.
undoMakeBucket(storageDisks, bucket)
}
return reducedErr
}
// Heals all the metadata associated for a given bucket, this function
// heals `policy.json`, `notification.xml` and `listeners.json`.
func healBucketMetadata(xlObj xlObjects, bucket string) error {
healBucketMetaFn := func(metaPath string) error {
if _, _, err := xlObj.HealObject(minioMetaBucket, metaPath); err != nil && !isErrObjectNotFound(err) {
return err
}
return nil
}
// Heal `policy.json` for missing entries, ignores if `policy.json` is not found.
policyPath := pathJoin(bucketConfigPrefix, bucket, bucketPolicyConfig)
if err := healBucketMetaFn(policyPath); err != nil {
return err
}
// Heal `notification.xml` for missing entries, ignores if `notification.xml` is not found.
nConfigPath := path.Join(bucketConfigPrefix, bucket, bucketNotificationConfig)
if err := healBucketMetaFn(nConfigPath); err != nil {
return err
}
// Heal `listeners.json` for missing entries, ignores if `listeners.json` is not found.
lConfigPath := path.Join(bucketConfigPrefix, bucket, bucketListenerConfig)
return healBucketMetaFn(lConfigPath)
}
// listAllBuckets lists all buckets from all disks. It also
// returns the occurrence of each buckets in all disks
func listAllBuckets(storageDisks []StorageAPI) (buckets map[string]VolInfo, bucketsOcc map[string]int, err error) {
buckets = make(map[string]VolInfo)
bucketsOcc = make(map[string]int)
for _, disk := range storageDisks {
if disk == nil {
continue
}
var volsInfo []VolInfo
volsInfo, err = disk.ListVols()
if err == nil {
for _, volInfo := range volsInfo {
// StorageAPI can send volume names which are
// incompatible with buckets, handle it and skip them.
if !IsValidBucketName(volInfo.Name) {
continue
}
// Skip special volume buckets.
if isMinioMetaBucketName(volInfo.Name) {
continue
}
// Increase counter per bucket name
bucketsOcc[volInfo.Name]++
// Save volume info under bucket name
buckets[volInfo.Name] = volInfo
}
continue
}
// Ignore any disks not found.
if errors.IsErrIgnored(err, bucketMetadataOpIgnoredErrs...) {
continue
}
break
}
return buckets, bucketsOcc, err
}
// reduceHealStatus - fetches the worst heal status in a provided slice
func reduceHealStatus(status []healStatus) healStatus {
worstStatus := healthy
for _, st := range status {
if st > worstStatus {
worstStatus = st
}
}
return worstStatus
}
// bucketHealStatus - returns the heal status of the provided bucket. Internally,
// this function lists all object heal status of objects inside meta bucket config
// directory and returns the worst heal status that can be found
func (xl xlObjects) bucketHealStatus(bucketName string) (healStatus, error) {
// A list of all the bucket config files
configFiles := []string{bucketPolicyConfig, bucketNotificationConfig, bucketListenerConfig}
// The status of buckets config files
configsHealStatus := make([]healStatus, len(configFiles))
// The list of errors found during checking heal status of each config file
configsErrs := make([]error, len(configFiles))
// The path of meta bucket that contains all config files
configBucket := path.Join(minioMetaBucket, bucketConfigPrefix, bucketName)
// Check of config files heal status in go-routines
var wg sync.WaitGroup
// Loop over config files
for idx, configFile := range configFiles {
wg.Add(1)
// Compute heal status of current config file
go func(bucket, object string, index int) {
defer wg.Done()
// Check
listObjectsHeal, err := xl.listObjectsHeal(bucket, object, "", "", 1)
// If any error, save and immediately quit
if err != nil {
configsErrs[index] = err
return
}
// Check if current bucket contains any not healthy config file and save heal status
if len(listObjectsHeal.Objects) > 0 {
configsHealStatus[index] = listObjectsHeal.Objects[0].HealObjectInfo.Status
}
}(configBucket, configFile, idx)
}
wg.Wait()
// Return any found error
for _, err := range configsErrs {
if err != nil {
return healthy, err
}
}
// Reduce and return heal status
return reduceHealStatus(configsHealStatus), nil
}
// ListBucketsHeal - Find all buckets that need to be healed
func (xl xlObjects) ListBucketsHeal() ([]BucketInfo, error) {
listBuckets := []BucketInfo{}
// List all buckets that can be found in all disks
buckets, occ, err := listAllBuckets(xl.storageDisks)
if err != nil {
return listBuckets, err
}
// Iterate over all buckets
for _, currBucket := range buckets {
// Check the status of bucket metadata
bucketHealStatus, err := xl.bucketHealStatus(currBucket.Name)
if err != nil {
return []BucketInfo{}, err
}
// If all metadata are sane, check if the bucket directory is present in all disks
if bucketHealStatus == healthy && occ[currBucket.Name] != len(xl.storageDisks) {
// Current bucket is missing in some of the storage disks
bucketHealStatus = canHeal
}
// Add current bucket to the returned result if not healthy
if bucketHealStatus != healthy {
listBuckets = append(listBuckets,
BucketInfo{
Name: currBucket.Name,
Created: currBucket.Created,
HealBucketInfo: &HealBucketInfo{Status: bucketHealStatus},
})
}
}
// Sort found buckets
sort.Sort(byBucketName(listBuckets))
return listBuckets, nil
}
// This function is meant for all the healing that needs to be done
// during startup i.e healing of buckets, bucket metadata (policy.json,
// notification.xml, listeners.json) etc. Currently this function
// supports quick healing of buckets, bucket metadata.
func quickHeal(xlObj xlObjects, writeQuorum int, readQuorum int) error {
// List all bucket name occurrence from all disks.
_, bucketOcc, err := listAllBuckets(xlObj.storageDisks)
if err != nil {
return err
}
// All bucket names and bucket metadata that should be healed.
for bucketName, occCount := range bucketOcc {
// Heal bucket only if healing is needed.
if occCount != len(xlObj.storageDisks) {
// Heal bucket and then proceed to heal bucket metadata if any.
if err = healBucket(xlObj.storageDisks, bucketName, writeQuorum); err == nil {
if err = healBucketMetadata(xlObj, bucketName); err == nil {
continue
}
return err
}
return err
}
}
// Success.
return nil
}
// Heals an object only the corrupted/missing erasure blocks.
func healObject(storageDisks []StorageAPI, bucket, object string, quorum int) (int, int, error) {
partsMetadata, errs := readAllXLMetadata(storageDisks, bucket, object)
// readQuorum suffices for xl.json since we use monotonic
// system time to break the tie when a split-brain situation
// arises.
if rErr := reduceReadQuorumErrs(errs, nil, quorum); rErr != nil {
return 0, 0, toObjectErr(rErr, bucket, object)
}
// List of disks having latest version of the object.
latestDisks, modTime := listOnlineDisks(storageDisks, partsMetadata, errs)
// List of disks having all parts as per latest xl.json - this
// does a full pass over the data and verifies all part files
// on disk
availableDisks, errs, aErr := disksWithAllParts(latestDisks, partsMetadata, errs, bucket,
object)
if aErr != nil {
return 0, 0, toObjectErr(aErr, bucket, object)
}
// Number of disks which don't serve data.
numOfflineDisks := 0
for index, disk := range storageDisks {
if disk == nil || errs[index] == errDiskNotFound {
numOfflineDisks++
}
}
// Number of disks which have all parts of the given object.
numAvailableDisks := 0
for _, disk := range availableDisks {
if disk != nil {
numAvailableDisks++
}
}
if numAvailableDisks == len(storageDisks) {
// nothing to heal in this case
return 0, 0, nil
}
// If less than read quorum number of disks have all the parts
// of the data, we can't reconstruct the erasure-coded data.
if numAvailableDisks < quorum {
return 0, 0, toObjectErr(errXLReadQuorum, bucket, object)
}
// List of disks having outdated version of the object or missing object.
outDatedDisks := outDatedDisks(storageDisks, availableDisks, errs, partsMetadata, bucket,
object)
// Number of disks that had outdated content of the given
// object and are online to be healed.
numHealedDisks := 0
for _, disk := range outDatedDisks {
if disk != nil {
numHealedDisks++
}
}
// Latest xlMetaV1 for reference. If a valid metadata is not
// present, it is as good as object not found.
latestMeta, pErr := pickValidXLMeta(partsMetadata, modTime)
if pErr != nil {
return 0, 0, toObjectErr(pErr, bucket, object)
}
for index, disk := range outDatedDisks {
// Before healing outdated disks, we need to remove
// xl.json and part files from "bucket/object/" so
// that rename(minioMetaBucket, "tmp/tmpuuid/",
// "bucket", "object/") succeeds.
if disk == nil {
// Not an outdated disk.
continue
}
// errFileNotFound implies that xl.json is missing. We
// may have object parts still present in the object
// directory. This needs to be deleted for object to
// healed successfully.
if errs[index] != nil && !errors.IsErr(errs[index], errFileNotFound) {
continue
}
// List and delete the object directory, ignoring
// errors.
files, err := disk.ListDir(bucket, object)
if err == nil {
for _, entry := range files {
_ = disk.DeleteFile(bucket,
pathJoin(object, entry))
}
}
}
// Reorder so that we have data disks first and parity disks next.
latestDisks = shuffleDisks(latestDisks, latestMeta.Erasure.Distribution)
outDatedDisks = shuffleDisks(outDatedDisks, latestMeta.Erasure.Distribution)
partsMetadata = shufflePartsMetadata(partsMetadata, latestMeta.Erasure.Distribution)
// We write at temporary location and then rename to final location.
tmpID := mustGetUUID()
// Checksum of the part files. checkSumInfos[index] will
// contain checksums of all the part files in the
// outDatedDisks[index]
checksumInfos := make([][]ChecksumInfo, len(outDatedDisks))
// Heal each part. erasureHealFile() will write the healed
// part to .minio/tmp/uuid/ which needs to be renamed later to
// the final location.
storage, err := NewErasureStorage(latestDisks,
latestMeta.Erasure.DataBlocks, latestMeta.Erasure.ParityBlocks, latestMeta.Erasure.BlockSize)
if err != nil {
return 0, 0, toObjectErr(err, bucket, object)
}
checksums := make([][]byte, len(latestDisks))
for partIndex := 0; partIndex < len(latestMeta.Parts); partIndex++ {
partName := latestMeta.Parts[partIndex].Name
partSize := latestMeta.Parts[partIndex].Size
erasure := latestMeta.Erasure
var algorithm BitrotAlgorithm
for i, disk := range storage.disks {
if disk != OfflineDisk {
info := partsMetadata[i].Erasure.GetChecksumInfo(partName)
algorithm = info.Algorithm
checksums[i] = info.Hash
}
}
// Heal the part file.
file, hErr := storage.HealFile(outDatedDisks, bucket, pathJoin(object, partName),
erasure.BlockSize, minioMetaTmpBucket, pathJoin(tmpID, partName), partSize,
algorithm, checksums)
if hErr != nil {
return 0, 0, toObjectErr(hErr, bucket, object)
}
// outDatedDisks that had write errors should not be
// written to for remaining parts, so we nil it out.
for i, disk := range outDatedDisks {
if disk == nil {
continue
}
// A non-nil stale disk which did not receive
// a healed part checksum had a write error.
if file.Checksums[i] == nil {
outDatedDisks[i] = nil
numHealedDisks--
continue
}
// append part checksums
checksumInfos[i] = append(checksumInfos[i],
ChecksumInfo{partName, file.Algorithm, file.Checksums[i]})
}
// If all disks are having errors, we give up.
if numHealedDisks == 0 {
return 0, 0, fmt.Errorf("all disks without up-to-date data had write errors")
}
}
// xl.json should be written to all the healed disks.
for index, disk := range outDatedDisks {
if disk == nil {
continue
}
partsMetadata[index] = latestMeta
partsMetadata[index].Erasure.Checksums = checksumInfos[index]
}
// Generate and write `xl.json` generated from other disks.
outDatedDisks, aErr = writeUniqueXLMetadata(outDatedDisks, minioMetaTmpBucket, tmpID,
partsMetadata, diskCount(outDatedDisks))
if aErr != nil {
return 0, 0, toObjectErr(aErr, bucket, object)
}
// Rename from tmp location to the actual location.
for _, disk := range outDatedDisks {
if disk == nil {
continue
}
// Attempt a rename now from healed data to final location.
aErr = disk.RenameFile(minioMetaTmpBucket, retainSlash(tmpID), bucket,
retainSlash(object))
if aErr != nil {
return 0, 0, toObjectErr(errors.Trace(aErr), bucket, object)
}
}
return numOfflineDisks, numHealedDisks, nil
}
// HealObject heals a given object for all its missing entries.
// FIXME: If an object object was deleted and one disk was down,
// and later the disk comes back up again, heal on the object
// should delete it.
func (xl xlObjects) HealObject(bucket, object string) (int, int, error) {
// Read metadata files from all the disks
partsMetadata, errs := readAllXLMetadata(xl.storageDisks, bucket, object)
// get read quorum for this object
readQuorum, _, err := objectQuorumFromMeta(xl, partsMetadata, errs)
if err != nil {
return 0, 0, err
}
// Lock the object before healing.
objectLock := globalNSMutex.NewNSLock(bucket, object)
if err := objectLock.GetRLock(globalHealingTimeout); err != nil {
return 0, 0, err
}
defer objectLock.RUnlock()
// Heal the object.
return healObject(xl.storageDisks, bucket, object, readQuorum)
}