135 lines
3.7 KiB
Go
135 lines
3.7 KiB
Go
/*
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* Minio Cloud Storage, (C) 2016 Minio, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package main
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import (
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"encoding/json"
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"errors"
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"hash/crc32"
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"path"
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)
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// Returns nil even if one of the slice elements is nil.
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// Else returns the error which occurs the most.
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func reduceErrs(errs []error) error {
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// In case the error type is not in the known error list.
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var unknownErr = errors.New("unknown error")
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var errTypes = []struct {
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err error // error type
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count int // occurrence count
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}{
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// List of known error types. Any new type that can be returned from StorageAPI should
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// be added to this list. Most common errors are listed here.
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{errDiskNotFound, 0}, {errFaultyDisk, 0}, {errFileAccessDenied, 0},
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{errFileNotFound, 0}, {errFileNameTooLong, 0}, {errVolumeNotFound, 0},
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{errDiskFull, 0},
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// unknownErr count - count of the number of unknown errors.
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{unknownErr, 0},
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}
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// In case unknownErr count occurs maximum number of times, unknownErrType is used to
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// to store it so that it can be used for the return error type.
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var unknownErrType error
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// For each err in []errs increment the corresponding count value.
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for _, err := range errs {
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if err == nil {
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// Return nil even if one of the elements is nil.
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return nil
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}
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for i := range errTypes {
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if errTypes[i].err == err {
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errTypes[i].count++
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break
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}
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if errTypes[i].err == unknownErr {
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errTypes[i].count++
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unknownErrType = err
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break
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}
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}
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}
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max := 0
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// Get the error type which has the maximum count.
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for i, errType := range errTypes {
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if errType.count > errTypes[max].count {
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max = i
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}
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}
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if errTypes[max].err == unknownErr {
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// Return the unknown error.
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return unknownErrType
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}
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return errTypes[max].err
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}
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// Validates if we have quorum based on the errors with errDiskNotFound.
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func isQuorum(errs []error, minQuorumCount int) bool {
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var diskFoundCount int
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for _, err := range errs {
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if err == errDiskNotFound {
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continue
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}
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diskFoundCount++
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}
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return diskFoundCount >= minQuorumCount
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}
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// Similar to 'len(slice)' but returns the actual elements count
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// skipping the unallocated elements.
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func diskCount(disks []StorageAPI) int {
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diskCount := 0
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for _, disk := range disks {
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if disk == nil {
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continue
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}
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diskCount++
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}
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return diskCount
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}
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// hashOrder - returns consistent hashed integers of count slice, based on the input token.
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func hashOrder(token string, count int) []int {
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if count < 0 {
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panic(errors.New("hashOrder count cannot be negative"))
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}
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nums := make([]int, count)
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tokenCrc := crc32.Checksum([]byte(token), crc32.IEEETable)
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start := int(uint32(tokenCrc)%uint32(count)) | 1
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for i := 1; i <= count; i++ {
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nums[i-1] = 1 + ((start + i) % count)
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}
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return nums
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}
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// readXLMeta reads `xl.json` and returns back XL metadata structure.
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func readXLMeta(disk StorageAPI, bucket string, object string) (xlMeta xlMetaV1, err error) {
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// Reads entire `xl.json`.
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buf, err := disk.ReadAll(bucket, path.Join(object, xlMetaJSONFile))
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if err != nil {
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return xlMetaV1{}, err
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}
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// Unmarshal xl metadata.
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if err = json.Unmarshal(buf, &xlMeta); err != nil {
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return xlMetaV1{}, err
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}
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// Return structured `xl.json`.
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return xlMeta, nil
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}
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