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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"
)
// 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
}
// Handles different cases properly.
switch reduceFormatErrs(sErrs, len(storageDisks)) {
case errCorruptedFormat:
if err = healFormatXLCorruptedDisks(storageDisks); err != nil {
return fmt.Errorf("Unable to repair corrupted format, %s", err)
}
case errSomeDiskUnformatted:
// All drives online but some report missing format.json.
if err = healFormatXLFreshDisks(storageDisks); err != nil {
// There was an unexpected unrecoverable error during healing.
return fmt.Errorf("Unable to heal backend %s", err)
}
case errSomeDiskOffline:
// FIXME: in future.
return fmt.Errorf("Unable to initialize format %s and %s", errSomeDiskOffline, errSomeDiskUnformatted)
}
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
}
// Heal bucket.
if err := healBucket(xl.storageDisks, bucket, xl.writeQuorum); err != nil {
return err
}
// Proceed to heal bucket metadata.
return healBucketMetadata(xl.storageDisks, bucket, xl.readQuorum)
}
// Heal bucket - create buckets on disks where it does not exist.
func healBucket(storageDisks []StorageAPI, bucket string, writeQuorum int) error {
bucketLock := globalNSMutex.NewNSLock(bucket, "")
bucketLock.Lock()
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] = traceError(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] = traceError(err)
return
}
if err = disk.MakeVol(bucket); err != nil {
dErrs[index] = traceError(err)
}
}
}(index, disk)
}
// Wait for all make vol to finish.
wg.Wait()
reducedErr := reduceWriteQuorumErrs(dErrs, bucketOpIgnoredErrs, writeQuorum)
if errorCause(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(storageDisks []StorageAPI, bucket string, readQuorum int) error {
healBucketMetaFn := func(metaPath string) error {
metaLock := globalNSMutex.NewNSLock(minioMetaBucket, metaPath)
metaLock.RLock()
defer metaLock.RUnlock()
// Heals the given file at metaPath.
if _, _, err := healObject(storageDisks, minioMetaBucket, metaPath, readQuorum); err != nil && !isErrObjectNotFound(err) {
return err
} // Success.
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 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(storageDisks []StorageAPI, writeQuorum int, readQuorum int) error {
// List all bucket name occurrence from all disks.
_, bucketOcc, err := listAllBuckets(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(storageDisks) {
// Heal bucket and then proceed to heal bucket metadata if any.
if err = healBucket(storageDisks, bucketName, writeQuorum); err == nil {
if err = healBucketMetadata(storageDisks, bucketName, readQuorum); err == nil {
continue
}
return err
}
return err
}
}
// Success.
return nil
}
// Heals an object only the corrupted/missing erasure blocks.
func healObject(storageDisks []StorageAPI, bucket string, 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 reducedErr := reduceReadQuorumErrs(errs, nil, quorum); reducedErr != nil {
return 0, 0, toObjectErr(reducedErr, bucket, object)
}
if !xlShouldHeal(storageDisks, partsMetadata, errs, bucket, object) {
// There is nothing to heal.
return 0, 0, nil
}
// 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.
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 {
switch {
case disk == nil, errs[index] == errDiskNotFound:
numOfflineDisks++
}
}
// Number of disks which have all parts of the given object.
numAvailableDisks := 0
for _, disk := range availableDisks {
switch {
case disk != nil:
numAvailableDisks++
}
}
// 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(".minio.sys", "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 && !isErr(errs[index], errFileNotFound) {
continue
}
// Outdated object with the same name exists that needs to be deleted.
outDatedMeta := partsMetadata[index]
// Consult valid metadata picked when there is no
// metadata available on this disk.
if isErr(errs[index], errFileNotFound) {
outDatedMeta = latestMeta
}
// Delete all the parts. Ignore if parts are not found.
for _, part := range outDatedMeta.Parts {
dErr := disk.DeleteFile(bucket, pathJoin(object, part.Name))
if dErr != nil && !isErr(dErr, errFileNotFound) {
return 0, 0, toObjectErr(traceError(dErr), bucket, object)
}
}
// Delete xl.json file. Ignore if xl.json not found.
dErr := disk.DeleteFile(bucket, pathJoin(object, xlMetaJSONFile))
if dErr != nil && !isErr(dErr, errFileNotFound) {
return 0, 0, toObjectErr(traceError(dErr), bucket, object)
}
}
// 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 fianal 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.
for partIndex := 0; partIndex < len(latestMeta.Parts); partIndex++ {
partName := latestMeta.Parts[partIndex].Name
partSize := latestMeta.Parts[partIndex].Size
erasure := latestMeta.Erasure
sumInfo := latestMeta.Erasure.GetCheckSumInfo(partName)
// Heal the part file.
checkSums, hErr := erasureHealFile(latestDisks, outDatedDisks,
bucket, pathJoin(object, partName),
minioMetaTmpBucket, pathJoin(tmpID, partName),
partSize, erasure.BlockSize, erasure.DataBlocks, erasure.ParityBlocks, sumInfo.Algorithm)
if hErr != nil {
return 0, 0, toObjectErr(hErr, bucket, object)
}
for index, sum := range checkSums {
if outDatedDisks[index] != nil {
checkSumInfos[index] = append(checkSumInfos[index], checkSumInfo{
Name: partName,
Algorithm: sumInfo.Algorithm,
Hash: sum,
})
}
}
}
// 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.Checksum = checkSumInfos[index]
}
// Generate and write `xl.json` generated from other disks.
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
}
// Remove any lingering partial data from current namespace.
aErr = disk.DeleteFile(bucket, retainSlash(object))
if aErr != nil && aErr != errFileNotFound {
return 0, 0, toObjectErr(traceError(aErr), bucket, object)
}
// 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(traceError(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) {
// Lock the object before healing.
objectLock := globalNSMutex.NewNSLock(bucket, object)
objectLock.RLock()
defer objectLock.RUnlock()
// Heal the object.
return healObject(xl.storageDisks, bucket, object, xl.readQuorum)
}