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minio/xl-v1-healing.go

135 lines
3.9 KiB

/*
* 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 main
import (
"encoding/json"
"path"
"sync"
)
// Get the highest integer from a given integer slice.
func highestInt(intSlice []int64, highestInt int64) (highestInteger int64) {
highestInteger = highestInt
for _, integer := range intSlice {
if highestInteger < integer {
highestInteger = integer
break
}
}
return highestInteger
}
// Extracts objects versions from xlMetaV1 slice and returns version slice.
func listObjectVersions(partsMetadata []xlMetaV1, errs []error) (versions []int64) {
versions = make([]int64, len(partsMetadata))
for index, metadata := range partsMetadata {
if errs[index] == nil {
versions[index] = metadata.Stat.Version
} else if errs[index] == errFileNotFound {
versions[index] = 1
} else {
versions[index] = -1
}
}
return versions
}
// Reads all `xl.json` metadata as a xlMetaV1 slice.
// Returns error slice indicating the failed metadata reads.
func (xl xlObjects) readAllXLMetadata(bucket, object string) ([]xlMetaV1, []error) {
errs := make([]error, len(xl.storageDisks))
metadataArray := make([]xlMetaV1, len(xl.storageDisks))
xlMetaPath := path.Join(object, xlMetaJSONFile)
var wg = &sync.WaitGroup{}
for index, disk := range xl.storageDisks {
if disk == nil {
errs[index] = errDiskNotFound
continue
}
wg.Add(1)
go func(index int, disk StorageAPI) {
defer wg.Done()
buffer, err := readAll(disk, bucket, xlMetaPath)
if err != nil {
errs[index] = err
return
}
err = json.Unmarshal(buffer, &metadataArray[index])
if err != nil {
// Unable to parse xl.json, set error.
errs[index] = err
return
}
errs[index] = nil
}(index, disk)
}
// Wait for all the routines to finish.
wg.Wait()
// Return all the metadata.
return metadataArray, errs
}
func (xl xlObjects) shouldHeal(onlineDisks []StorageAPI) (heal bool) {
onlineDiskCount := diskCount(onlineDisks)
// If online disks count is lesser than configured disks, most
// probably we need to heal the file, additionally verify if the
// count is lesser than readQuorum, if not we throw an error.
if onlineDiskCount < len(xl.storageDisks) {
// Online disks lesser than total storage disks, needs to be
// healed. unless we do not have readQuorum.
heal = true
// Verify if online disks count are lesser than readQuorum
// threshold, return an error.
if onlineDiskCount < xl.readQuorum {
errorIf(errXLReadQuorum, "Unable to establish read quorum, disks are offline.")
return false
}
}
return heal
}
// Returns slice of online disks needed.
// - slice returing readable disks.
// - xlMetaV1
// - bool value indicating if healing is needed.
// - error if any.
func (xl xlObjects) listOnlineDisks(partsMetadata []xlMetaV1, errs []error) (onlineDisks []StorageAPI, version int64, err error) {
onlineDisks = make([]StorageAPI, len(xl.storageDisks))
// Do we have read Quorum?.
if !isQuorum(errs, xl.readQuorum) {
return nil, 0, errXLReadQuorum
}
// List all the file versions from partsMetadata list.
versions := listObjectVersions(partsMetadata, errs)
// Get highest object version.
highestVersion := highestInt(versions, int64(1))
// Pick online disks with version set to highestVersion.
for index, version := range versions {
if version == highestVersion {
onlineDisks[index] = xl.storageDisks[index]
} else {
onlineDisks[index] = nil
}
}
return onlineDisks, highestVersion, nil
}