minio/cmd/metacache-manager.go
2021-02-24 22:24:51 -08:00

271 lines
6.6 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 (
"context"
"fmt"
"runtime/debug"
"sync"
"time"
"github.com/minio/minio/cmd/logger"
)
// localMetacacheMgr is the *local* manager for this peer.
// It should never be used directly since buckets are
// distributed deterministically.
// Therefore no cluster locks are required.
var localMetacacheMgr = &metacacheManager{
buckets: make(map[string]*bucketMetacache),
trash: make(map[string]metacache),
}
type metacacheManager struct {
mu sync.RWMutex
init sync.Once
buckets map[string]*bucketMetacache
trash map[string]metacache // Recently deleted lists.
}
const metacacheManagerTransientBucket = "**transient**"
const metacacheMaxEntries = 5000
// initManager will start async saving the cache.
func (m *metacacheManager) initManager() {
// Add a transient bucket.
tb := newBucketMetacache(metacacheManagerTransientBucket, false)
tb.transient = true
m.buckets[metacacheManagerTransientBucket] = tb
// Start saver when object layer is ready.
go func() {
objAPI := newObjectLayerFn()
for objAPI == nil {
time.Sleep(time.Second)
objAPI = newObjectLayerFn()
}
if !globalIsErasure {
logger.Info("metacacheManager was initialized in non-erasure mode, skipping save")
return
}
t := time.NewTicker(time.Minute)
defer t.Stop()
var exit bool
bg := context.Background()
for !exit {
select {
case <-t.C:
case <-GlobalContext.Done():
exit = true
}
m.mu.RLock()
for _, v := range m.buckets {
if !exit {
v.cleanup()
}
logger.LogIf(bg, v.save(bg))
}
m.mu.RUnlock()
m.mu.Lock()
for k, v := range m.trash {
if time.Since(v.lastUpdate) > metacacheMaxRunningAge {
v.delete(context.Background())
delete(m.trash, k)
}
}
m.mu.Unlock()
}
}()
}
// findCache will get a metacache.
func (m *metacacheManager) findCache(ctx context.Context, o listPathOptions) metacache {
if o.Transient || isReservedOrInvalidBucket(o.Bucket, false) {
return m.getTransient().findCache(o)
}
m.mu.RLock()
b, ok := m.buckets[o.Bucket]
if ok {
m.mu.RUnlock()
return b.findCache(o)
}
if meta, ok := m.trash[o.ID]; ok {
m.mu.RUnlock()
return meta
}
m.mu.RUnlock()
return m.getBucket(ctx, o.Bucket).findCache(o)
}
// updateCacheEntry will update non-transient state.
func (m *metacacheManager) updateCacheEntry(update metacache) (metacache, error) {
m.mu.RLock()
if meta, ok := m.trash[update.id]; ok {
m.mu.RUnlock()
return meta, nil
}
b, ok := m.buckets[update.bucket]
m.mu.RUnlock()
if ok {
return b.updateCacheEntry(update)
}
// We should have either a trashed bucket or this
return metacache{}, errVolumeNotFound
}
// getBucket will get a bucket metacache or load it from disk if needed.
func (m *metacacheManager) getBucket(ctx context.Context, bucket string) *bucketMetacache {
m.init.Do(m.initManager)
// Return a transient bucket for invalid or system buckets.
if isReservedOrInvalidBucket(bucket, false) {
return m.getTransient()
}
m.mu.RLock()
b, ok := m.buckets[bucket]
m.mu.RUnlock()
if ok {
if b.bucket != bucket {
logger.Info("getBucket: cached bucket %s does not match this bucket %s", b.bucket, bucket)
debug.PrintStack()
}
return b
}
m.mu.Lock()
// See if someone else fetched it while we waited for the lock.
b, ok = m.buckets[bucket]
if ok {
m.mu.Unlock()
if b.bucket != bucket {
logger.Info("getBucket: newly cached bucket %s does not match this bucket %s", b.bucket, bucket)
debug.PrintStack()
}
return b
}
// Load bucket. If we fail return the transient bucket.
b, err := loadBucketMetaCache(ctx, bucket)
if err != nil {
m.mu.Unlock()
logger.LogIf(ctx, err)
return m.getTransient()
}
if b.bucket != bucket {
logger.LogIf(ctx, fmt.Errorf("getBucket: loaded bucket %s does not match this bucket %s", b.bucket, bucket))
}
m.buckets[bucket] = b
m.mu.Unlock()
return b
}
// deleteBucketCache will delete the bucket cache if it exists.
func (m *metacacheManager) deleteBucketCache(bucket string) {
m.init.Do(m.initManager)
m.mu.Lock()
b, ok := m.buckets[bucket]
if !ok {
m.mu.Unlock()
return
}
delete(m.buckets, bucket)
m.mu.Unlock()
// Since deletes may take some time we try to do it without
// holding lock to m all the time.
b.mu.Lock()
defer b.mu.Unlock()
for k, v := range b.caches {
if time.Since(v.lastUpdate) > metacacheMaxRunningAge {
v.delete(context.Background())
continue
}
v.error = "Bucket deleted"
v.status = scanStateError
m.mu.Lock()
m.trash[k] = v
m.mu.Unlock()
}
}
// deleteAll will delete all caches.
func (m *metacacheManager) deleteAll() {
m.init.Do(m.initManager)
m.mu.Lock()
defer m.mu.Unlock()
for bucket, b := range m.buckets {
b.deleteAll()
if !b.transient {
delete(m.buckets, bucket)
}
}
}
// getTransient will return a transient bucket.
func (m *metacacheManager) getTransient() *bucketMetacache {
m.init.Do(m.initManager)
m.mu.RLock()
bmc := m.buckets[metacacheManagerTransientBucket]
m.mu.RUnlock()
return bmc
}
// checkMetacacheState should be used if data is not updating.
// Should only be called if a failure occurred.
func (o listPathOptions) checkMetacacheState(ctx context.Context, rpc *peerRESTClient) error {
// We operate on a copy...
o.Create = false
var cache metacache
if rpc == nil || o.Transient {
cache = localMetacacheMgr.findCache(ctx, o)
} else {
c, err := rpc.GetMetacacheListing(ctx, o)
if err != nil {
return err
}
cache = *c
}
if cache.status == scanStateNone || cache.fileNotFound {
return errFileNotFound
}
if cache.status == scanStateSuccess || cache.status == scanStateStarted {
if time.Since(cache.lastUpdate) > metacacheMaxRunningAge {
// We got a stale entry, mark error on handling server.
err := fmt.Errorf("timeout: list %s not updated", cache.id)
cache.error = err.Error()
cache.status = scanStateError
if rpc == nil || o.Transient {
localMetacacheMgr.updateCacheEntry(cache)
} else {
rpc.UpdateMetacacheListing(ctx, cache)
}
return err
}
return nil
}
if cache.error != "" {
return fmt.Errorf("async cache listing failed with: %s", cache.error)
}
return nil
}