minio/cmd/metacache-bucket.go
Klaus Post 6135f072d2
Fix invalidated metacaches (#10784)
* Fix caches having EOF marked as a failure.
* Simplify cache updates.
* Provide context for checkMetacacheState failures.
* Log 499 when the client disconnects.
2020-10-30 09:33:16 -07:00

432 lines
11 KiB
Go

/*
* MinIO Cloud Storage, (C) 2020 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 (
"bytes"
"context"
"errors"
"fmt"
"io"
"runtime/debug"
"strings"
"sync"
"time"
"github.com/klauspost/compress/s2"
"github.com/minio/minio/cmd/logger"
"github.com/minio/minio/pkg/hash"
"github.com/tinylib/msgp/msgp"
)
//go:generate msgp -file $GOFILE -unexported
// a bucketMetacache keeps track of all caches generated
// for a bucket.
type bucketMetacache struct {
// Name of bucket
bucket string
// caches indexed by id.
caches map[string]metacache
// Internal state
mu sync.RWMutex `msg:"-"`
updated bool `msg:"-"`
transient bool `msg:"-"` // bucket used for non-persisted caches.
}
// newBucketMetacache creates a new bucketMetacache.
func newBucketMetacache(bucket string) *bucketMetacache {
return &bucketMetacache{
bucket: bucket,
caches: make(map[string]metacache, 10),
}
}
// loadBucketMetaCache will load the cache from the object layer.
// If the cache cannot be found a new one is created.
func loadBucketMetaCache(ctx context.Context, bucket string) (*bucketMetacache, error) {
objAPI := newObjectLayerFn()
for objAPI == nil {
select {
case <-ctx.Done():
return nil, ctx.Err()
case <-time.After(250 * time.Millisecond):
}
objAPI = newObjectLayerFn()
if objAPI == nil {
logger.LogIf(ctx, fmt.Errorf("loadBucketMetaCache: object layer not ready. bucket: %q", bucket))
}
}
var meta bucketMetacache
var decErr error
var wg sync.WaitGroup
wg.Add(1)
r, w := io.Pipe()
go func() {
defer wg.Done()
dec := s2DecPool.Get().(*s2.Reader)
dec.Reset(r)
decErr = meta.DecodeMsg(msgp.NewReader(dec))
dec.Reset(nil)
s2DecPool.Put(dec)
r.CloseWithError(decErr)
}()
// Use global context for this.
err := objAPI.GetObject(GlobalContext, minioMetaBucket, pathJoin("buckets", bucket, ".metacache", "index.s2"), 0, -1, w, "", ObjectOptions{})
logger.LogIf(ctx, w.CloseWithError(err))
if err != nil {
if isErrObjectNotFound(err) {
err = nil
} else {
logger.LogIf(ctx, err)
}
return newBucketMetacache(bucket), err
}
wg.Wait()
if decErr != nil {
// Log the error, but assume the data is lost and return a fresh bucket.
// Otherwise a broken cache will never recover.
logger.LogIf(ctx, decErr)
return newBucketMetacache(bucket), nil
}
// Sanity check...
if meta.bucket != bucket {
logger.Info("loadBucketMetaCache: loaded cache name mismatch, want %s, got %s. Discarding.", bucket, meta.bucket)
return newBucketMetacache(bucket), nil
}
return &meta, nil
}
// save the bucket cache to the object storage.
func (b *bucketMetacache) save(ctx context.Context) error {
if b.transient {
return nil
}
objAPI := newObjectLayerFn()
if objAPI == nil {
return errServerNotInitialized
}
// Keep lock while we marshal.
// We need a write lock since we update 'updated'
b.mu.Lock()
if !b.updated {
b.mu.Unlock()
return nil
}
// Save as s2 compressed msgpack
tmp := bytes.NewBuffer(make([]byte, 0, b.Msgsize()))
enc := s2.NewWriter(tmp)
err := msgp.Encode(enc, b)
if err != nil {
b.mu.Unlock()
return err
}
err = enc.Close()
if err != nil {
b.mu.Unlock()
return err
}
b.updated = false
b.mu.Unlock()
hr, err := hash.NewReader(tmp, int64(tmp.Len()), "", "", int64(tmp.Len()), false)
if err != nil {
return err
}
_, err = objAPI.PutObject(ctx, minioMetaBucket, pathJoin("buckets", b.bucket, ".metacache", "index.s2"), NewPutObjReader(hr, nil, nil), ObjectOptions{})
logger.LogIf(ctx, err)
return err
}
// findCache will attempt to find a matching cache for the provided options.
// If a cache with the same ID exists already it will be returned.
// If none can be found a new is created with the provided ID.
func (b *bucketMetacache) findCache(o listPathOptions) metacache {
if b == nil {
logger.Info("bucketMetacache.findCache: nil cache for bucket %s", o.Bucket)
return metacache{}
}
if o.Bucket != b.bucket && !b.transient {
logger.Info("bucketMetacache.findCache: bucket %s does not match this bucket %s", o.Bucket, b.bucket)
debug.PrintStack()
return metacache{}
}
debugPrint := func(msg string, data ...interface{}) {}
if false {
debugPrint = logger.Info
}
// Grab a write lock, since we create one if we cannot find one.
if o.Create {
b.mu.Lock()
defer b.mu.Unlock()
} else {
b.mu.RLock()
defer b.mu.RUnlock()
}
// Check if exists already.
if c, ok := b.caches[o.ID]; ok {
return c
}
var best metacache
for _, cached := range b.caches {
// Never return transient caches if there is no id.
if b.transient {
break
}
if cached.status == scanStateError || cached.dataVersion != metacacheStreamVersion {
debugPrint("cache %s state or stream version mismatch", cached.id)
continue
}
if cached.startedCycle < o.OldestCycle {
debugPrint("cache %s cycle too old", cached.id)
continue
}
// Root of what we are looking for must at least have
if !strings.HasPrefix(o.BaseDir, cached.root) {
debugPrint("cache %s prefix mismatch, cached:%v, want:%v", cached.id, cached.root, o.BaseDir)
continue
}
// If the existing listing wasn't recursive root must match.
if !cached.recursive && o.BaseDir != cached.root {
debugPrint("cache %s non rec prefix mismatch, cached:%v, want:%v", cached.id, cached.root, o.BaseDir)
continue
}
if o.Recursive && !cached.recursive {
debugPrint("cache %s not recursive", cached.id)
// If this is recursive the cached listing must be as well.
continue
}
if o.Separator != slashSeparator && !cached.recursive {
debugPrint("cache %s not slashsep and not recursive", cached.id)
// Non slash separator requires recursive.
continue
}
if cached.ended.IsZero() && time.Since(cached.lastUpdate) > metacacheMaxRunningAge {
debugPrint("cache %s not running, time: %v", cached.id, time.Since(cached.lastUpdate))
// Abandoned
continue
}
if !cached.ended.IsZero() && cached.endedCycle <= o.OldestCycle {
debugPrint("cache %s ended and cycle (%v) <= oldest allowed (%v)", cached.id, cached.endedCycle, o.OldestCycle)
// If scan has ended the oldest requested must be less.
continue
}
if cached.started.Before(best.started) {
debugPrint("cache %s disregarded - we have a better", cached.id)
// If we already have a newer, keep that.
continue
}
best = cached
}
if !best.started.IsZero() {
if o.Create {
best.lastHandout = UTCNow()
b.caches[best.id] = best
b.updated = true
}
debugPrint("returning cached %s, status: %v, ended: %v", best.id, best.status, best.ended)
return best
}
if !o.Create {
return metacache{
id: o.ID,
bucket: o.Bucket,
status: scanStateNone,
}
}
// Create new and add.
best = o.newMetacache()
b.caches[o.ID] = best
b.updated = true
return best
}
// cleanup removes redundant and outdated entries.
func (b *bucketMetacache) cleanup() {
// Entries to remove.
remove := make(map[string]struct{})
currentCycle := intDataUpdateTracker.current()
debugPrint := func(msg string, data ...interface{}) {}
if false {
debugPrint = logger.Info
}
b.mu.RLock()
for id, cache := range b.caches {
if b.transient && time.Since(cache.started) > time.Hour {
// Keep transient caches only for 1 hour.
remove[id] = struct{}{}
}
if !cache.worthKeeping(currentCycle) {
debugPrint("cache %s not worth keeping", id)
remove[id] = struct{}{}
}
if cache.id != id {
logger.Info("cache ID mismatch %s != %s", id, cache.id)
remove[id] = struct{}{}
}
if cache.bucket != b.bucket && !b.transient {
logger.Info("cache bucket mismatch %s != %s", b.bucket, cache.bucket)
remove[id] = struct{}{}
}
}
// Check all non-deleted against eachother.
// O(n*n), but should still be rather quick.
for id, cache := range b.caches {
if _, ok := remove[id]; ok {
continue
}
for _, cache2 := range b.caches {
if cache.canBeReplacedBy(&cache2) {
debugPrint("cache %s can be replaced by %s", id, cache2.id)
remove[id] = struct{}{}
break
} else {
debugPrint("cache %s can be NOT replaced by %s", id, cache2.id)
}
}
}
b.mu.RUnlock()
for id := range remove {
b.deleteCache(id)
}
}
// updateCache will update a cache by id.
// If the cache cannot be found nil is returned.
// The bucket cache will be locked until the done .
func (b *bucketMetacache) updateCache(id string) (cache *metacache, done func()) {
b.mu.Lock()
c, ok := b.caches[id]
if !ok {
b.mu.Unlock()
return nil, func() {}
}
return &c, func() {
c.lastUpdate = UTCNow()
b.caches[id] = c
b.mu.Unlock()
}
}
// updateCacheEntry will update a cache.
// Returns the updated status.
func (b *bucketMetacache) updateCacheEntry(update metacache) (metacache, error) {
b.mu.Lock()
defer b.mu.Unlock()
existing, ok := b.caches[update.id]
if !ok {
logger.Info("updateCacheEntry: bucket %s list id %v not found", b.bucket, update.id)
return update, errFileNotFound
}
existing.lastUpdate = UTCNow()
if existing.status == scanStateStarted && update.status == scanStateSuccess {
existing.ended = UTCNow()
existing.endedCycle = update.endedCycle
}
if existing.status == scanStateStarted && update.status != scanStateStarted {
existing.status = update.status
}
if existing.error == "" && update.error != "" {
existing.error = update.error
existing.status = scanStateError
existing.ended = UTCNow()
}
existing.fileNotFound = existing.fileNotFound || update.fileNotFound
b.caches[update.id] = existing
b.updated = true
return existing, nil
}
// getCache will return a clone of a specific metacache.
// Will return nil if the cache doesn't exist.
func (b *bucketMetacache) getCache(id string) *metacache {
b.mu.RLock()
c, ok := b.caches[id]
b.mu.RUnlock()
if !ok {
return nil
}
return &c
}
// deleteAll will delete all on disk data for ALL caches.
// Deletes are performed concurrently.
func (b *bucketMetacache) deleteAll() {
b.mu.Lock()
defer b.mu.Unlock()
ctx := context.Background()
ez, ok := newObjectLayerFn().(*erasureServerSets)
if !ok {
logger.LogIf(ctx, errors.New("bucketMetacache: expected objAPI to be *erasureZones"))
return
}
var wg sync.WaitGroup
for id := range b.caches {
wg.Add(1)
go func(cache metacache) {
defer wg.Done()
logger.LogIf(ctx, ez.deleteAll(ctx, minioMetaBucket, metacachePrefixForID(cache.bucket, cache.id)))
}(b.caches[id])
delete(b.caches, id)
}
wg.Wait()
}
// deleteCache will delete a specific cache and all files related to it across the cluster.
func (b *bucketMetacache) deleteCache(id string) {
b.mu.Lock()
c, ok := b.caches[id]
if ok {
delete(b.caches, id)
b.updated = true
}
b.mu.Unlock()
if ok {
ctx := context.Background()
objAPI := newObjectLayerFn()
if objAPI == nil {
logger.LogIf(ctx, errors.New("bucketMetacache: no object layer"))
return
}
ez, ok := objAPI.(*erasureServerSets)
if !ok {
logger.LogIf(ctx, errors.New("bucketMetacache: expected objAPI to be *erasureServerSets"))
return
}
logger.LogIf(ctx, ez.deleteAll(ctx, minioMetaBucket, metacachePrefixForID(c.bucket, c.id)))
}
}