minio/cmd/erasure-healing-common.go
2022-12-06 13:46:50 -08:00

338 lines
10 KiB
Go

// Copyright (c) 2015-2021 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package cmd
import (
"bytes"
"context"
"time"
"github.com/minio/madmin-go/v2"
)
// commonTime returns a maximally occurring time from a list of time.
func commonTimeAndOccurence(times []time.Time, group time.Duration) (maxTime time.Time, maxima int) {
timeOccurenceMap := make(map[int64]int, len(times))
groupNano := group.Nanoseconds()
// Ignore the uuid sentinel and count the rest.
for _, t := range times {
if t.Equal(timeSentinel) || t.IsZero() {
continue
}
nano := t.UnixNano()
if group > 0 {
for k := range timeOccurenceMap {
if k == nano {
// We add to ourself later
continue
}
diff := k - nano
if diff < 0 {
diff = -diff
}
// We are within the limit
if diff < groupNano {
timeOccurenceMap[k]++
}
}
}
// Add ourself...
timeOccurenceMap[nano]++
}
maxima = 0 // Counter for remembering max occurrence of elements.
latest := int64(0)
// Find the common cardinality from previously collected
// occurrences of elements.
for nano, count := range timeOccurenceMap {
if count < maxima {
continue
}
// We are at or above maxima
if count > maxima || nano > latest {
maxima = count
latest = nano
}
}
// Return the collected common max time, with maxima
return time.Unix(0, latest).UTC(), maxima
}
// commonTime returns a maximally occurring time from a list of time.
func commonTime(modTimes []time.Time) (modTime time.Time) {
modTime, _ = commonTimeAndOccurence(modTimes, 0)
return modTime
}
// Beginning of unix time is treated as sentinel value here.
var (
timeSentinel = time.Unix(0, 0).UTC()
timeSentinel1970 = time.Unix(0, 1).UTC() // 1970 used for special cases when xlmeta.version == 0
)
// Boot modTimes up to disk count, setting the value to time sentinel.
func bootModtimes(diskCount int) []time.Time {
modTimes := make([]time.Time, diskCount)
// Boots up all the modtimes.
for i := range modTimes {
modTimes[i] = timeSentinel
}
return modTimes
}
// Extracts list of times from FileInfo slice and returns, skips
// slice elements which have errors.
func listObjectModtimes(partsMetadata []FileInfo, errs []error) (modTimes []time.Time) {
modTimes = bootModtimes(len(partsMetadata))
for index, metadata := range partsMetadata {
if errs[index] != nil {
continue
}
// Once the file is found, save the uuid saved on disk.
modTimes[index] = metadata.ModTime
}
return modTimes
}
func filterOnlineDisksInplace(fi FileInfo, partsMetadata []FileInfo, onlineDisks []StorageAPI) {
for i, meta := range partsMetadata {
if fi.XLV1 == meta.XLV1 {
continue
}
onlineDisks[i] = nil
}
}
// Extracts list of disk mtimes from FileInfo slice and returns, skips
// slice elements that have errors.
func listObjectDiskMtimes(partsMetadata []FileInfo) (diskMTimes []time.Time) {
diskMTimes = bootModtimes(len(partsMetadata))
for index, metadata := range partsMetadata {
if metadata.IsValid() {
// Once the file is found, save the disk mtime saved on disk.
diskMTimes[index] = metadata.DiskMTime
}
}
return diskMTimes
}
// Notes:
// There are 5 possible states a disk could be in,
// 1. __online__ - has the latest copy of xl.meta - returned by listOnlineDisks
//
// 2. __offline__ - err == errDiskNotFound
//
// 3. __availableWithParts__ - has the latest copy of xl.meta and has all
// parts with checksums matching; returned by disksWithAllParts
//
// 4. __outdated__ - returned by outDatedDisk, provided []StorageAPI
// returned by diskWithAllParts is passed for latestDisks.
// - has an old copy of xl.meta
// - doesn't have xl.meta (errFileNotFound)
// - has the latest xl.meta but one or more parts are corrupt
//
// 5. __missingParts__ - has the latest copy of xl.meta but has some parts
// missing. This is identified separately since this may need manual
// inspection to understand the root cause. E.g, this could be due to
// backend filesystem corruption.
// listOnlineDisks - returns
// - a slice of disks where disk having 'older' xl.meta (or nothing)
// are set to nil.
// - latest (in time) of the maximally occurring modTime(s).
func listOnlineDisks(disks []StorageAPI, partsMetadata []FileInfo, errs []error) (onlineDisks []StorageAPI, modTime time.Time) {
onlineDisks = make([]StorageAPI, len(disks))
// List all the file commit ids from parts metadata.
modTimes := listObjectModtimes(partsMetadata, errs)
// Reduce list of UUIDs to a single common value.
modTime = commonTime(modTimes)
// Create a new online disks slice, which have common uuid.
for index, t := range modTimes {
if partsMetadata[index].IsValid() && t.Equal(modTime) {
onlineDisks[index] = disks[index]
} else {
onlineDisks[index] = nil
}
}
return onlineDisks, modTime
}
// disksWithAllParts - This function needs to be called with
// []StorageAPI returned by listOnlineDisks. Returns,
//
// - disks which have all parts specified in the latest xl.meta.
//
// - slice of errors about the state of data files on disk - can have
// a not-found error or a hash-mismatch error.
func disksWithAllParts(ctx context.Context, onlineDisks []StorageAPI, partsMetadata []FileInfo,
errs []error, latestMeta FileInfo, bucket, object string,
scanMode madmin.HealScanMode) ([]StorageAPI, []error, time.Time,
) {
var diskMTime time.Time
var shardFix bool
if !latestMeta.DataShardFixed() {
diskMTime = pickValidDiskTimeWithQuorum(partsMetadata,
latestMeta.Erasure.DataBlocks)
}
availableDisks := make([]StorageAPI, len(onlineDisks))
dataErrs := make([]error, len(onlineDisks))
inconsistent := 0
for i, meta := range partsMetadata {
if !meta.IsValid() {
// Since for majority of the cases erasure.Index matches with erasure.Distribution we can
// consider the offline disks as consistent.
continue
}
if !meta.Deleted {
if len(meta.Erasure.Distribution) != len(onlineDisks) {
// Erasure distribution seems to have lesser
// number of items than number of online disks.
inconsistent++
continue
}
if meta.Erasure.Distribution[i] != meta.Erasure.Index {
// Mismatch indexes with distribution order
inconsistent++
}
}
}
erasureDistributionReliable := true
if inconsistent > len(partsMetadata)/2 {
// If there are too many inconsistent files, then we can't trust erasure.Distribution (most likely
// because of bugs found in CopyObject/PutObjectTags) https://github.com/minio/minio/pull/10772
erasureDistributionReliable = false
}
for i, onlineDisk := range onlineDisks {
if errs[i] != nil {
dataErrs[i] = errs[i]
continue
}
if onlineDisk == OfflineDisk {
dataErrs[i] = errDiskNotFound
continue
}
meta := partsMetadata[i]
if !meta.ModTime.Equal(latestMeta.ModTime) || meta.DataDir != latestMeta.DataDir {
dataErrs[i] = errFileCorrupt
partsMetadata[i] = FileInfo{}
continue
}
if erasureDistributionReliable {
if !meta.IsValid() {
partsMetadata[i] = FileInfo{}
dataErrs[i] = errFileCorrupt
continue
}
if !meta.Deleted {
if len(meta.Erasure.Distribution) != len(onlineDisks) {
// Erasure distribution is not the same as onlineDisks
// attempt a fix if possible, assuming other entries
// might have the right erasure distribution.
partsMetadata[i] = FileInfo{}
dataErrs[i] = errFileCorrupt
continue
}
// Since erasure.Distribution is trustable we can fix the mismatching erasure.Index
if meta.Erasure.Distribution[i] != meta.Erasure.Index {
partsMetadata[i] = FileInfo{}
dataErrs[i] = errFileCorrupt
continue
}
}
}
if !diskMTime.Equal(timeSentinel) && !diskMTime.IsZero() {
if !partsMetadata[i].AcceptableDelta(diskMTime, shardDiskTimeDelta) {
// not with in acceptable delta, skip.
// If disk mTime mismatches it is considered outdated
// https://github.com/minio/minio/pull/13803
//
// This check only is active if we could find maximally
// occurring disk mtimes that are somewhat same across
// the quorum. Allowing to skip those shards which we
// might think are wrong.
shardFix = true
partsMetadata[i] = FileInfo{}
dataErrs[i] = errFileCorrupt
continue
}
}
// Always check data, if we got it.
if (len(meta.Data) > 0 || meta.Size == 0) && len(meta.Parts) > 0 {
checksumInfo := meta.Erasure.GetChecksumInfo(meta.Parts[0].Number)
dataErrs[i] = bitrotVerify(bytes.NewReader(meta.Data),
int64(len(meta.Data)),
meta.Erasure.ShardFileSize(meta.Size),
checksumInfo.Algorithm,
checksumInfo.Hash, meta.Erasure.ShardSize())
if dataErrs[i] == nil {
// All parts verified, mark it as all data available.
availableDisks[i] = onlineDisk
} else {
// upon errors just make that disk's fileinfo invalid
partsMetadata[i] = FileInfo{}
}
continue
}
meta.DataDir = latestMeta.DataDir
switch scanMode {
case madmin.HealDeepScan:
// disk has a valid xl.meta but may not have all the
// parts. This is considered an outdated disk, since
// it needs healing too.
if !meta.Deleted && !meta.IsRemote() {
dataErrs[i] = onlineDisk.VerifyFile(ctx, bucket, object, meta)
}
case madmin.HealNormalScan:
if !meta.Deleted && !meta.IsRemote() {
dataErrs[i] = onlineDisk.CheckParts(ctx, bucket, object, meta)
}
}
if dataErrs[i] == nil {
// All parts verified, mark it as all data available.
availableDisks[i] = onlineDisk
} else {
// upon errors just make that disk's fileinfo invalid
partsMetadata[i] = FileInfo{}
}
}
if shardFix {
// Only when shard is fixed return an appropriate disk mtime value.
return availableDisks, dataErrs, diskMTime
} // else return timeSentinel for disk mtime
return availableDisks, dataErrs, timeSentinel
}