Repository navigation
Expand file tree
/
Copy pathdisk-cache.go
10BC8
More file actions
855 lines (786 loc) · 28.1 KB
/
Copy pathdisk-cache.go
File metadata and controls
855 lines (786 loc) · 28.1 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
/*
* MinIO Cloud Storage, (C) 2019,2020 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"
"errors"
"fmt"
"io"
"net/http"
"strconv"
"strings"
"sync"
"sync/atomic"
"time"
"github.com/minio/minio/cmd/config/cache"
xhttp "github.com/minio/minio/cmd/http"
"github.com/minio/minio/cmd/logger"
objectlock "github.com/minio/minio/pkg/bucket/object/lock"
"github.com/minio/minio/pkg/color"
"github.com/minio/minio/pkg/hash"
"github.com/minio/minio/pkg/sync/errgroup"
"github.com/minio/minio/pkg/wildcard"
)
const (
cacheBlkSize = 1 << 20
cacheGCInterval = time.Minute * 30
writeBackStatusHeader = ReservedMetadataPrefixLower + "write-back-status"
writeBackRetryHeader = ReservedMetadataPrefixLower + "write-back-retry"
)
type cacheCommitStatus string
const (
// CommitPending - cache writeback with backend is pending.
CommitPending cacheCommitStatus = "pending"
// CommitComplete - cache writeback completed ok.
CommitComplete cacheCommitStatus = "complete"
// CommitFailed - cache writeback needs a retry.
CommitFailed cacheCommitStatus = "failed"
)
// String returns string representation of status
func (s cacheCommitStatus) String() string {
return string(s)
}
// CacheStorageInfo - represents total, free capacity of
// underlying cache storage.
type CacheStorageInfo struct {
Total uint64 // Total cache disk space.
Free uint64 // Free cache available space.
}
// CacheObjectLayer implements primitives for cache object API layer.
type CacheObjectLayer interface {
// Object operations.
GetObjectNInfo(ctx context.Context, bucket, object string, rs *HTTPRangeSpec, h http.Header, lockType LockType, opts ObjectOptions) (gr *GetObjectReader, err error)
GetObjectInfo(ctx context.Context, bucket, object string, opts ObjectOptions) (objInfo ObjectInfo, err error)
DeleteObject(ctx context.Context, bucket, object string, opts ObjectOptions) (ObjectInfo, error)
DeleteObjects(ctx context.Context, bucket string, objects []ObjectToDelete, opts ObjectOptions) ([]DeletedObject, []error)
PutObject(ctx context.Context, bucket, object string, data *PutObjReader, opts ObjectOptions) (objInfo ObjectInfo, err error)
CopyObject(ctx context.Context, srcBucket, srcObject, destBucket, destObject string, srcInfo ObjectInfo, srcOpts, dstOpts ObjectOptions) (objInfo ObjectInfo, err error)
// Storage operations.
StorageInfo(ctx context.Context) CacheStorageInfo
CacheStats() *CacheStats
}
// Abstracts disk caching - used by the S3 layer
type cacheObjects struct {
// slice of cache drives
cache []*diskCache
// file path patterns to exclude from cache
exclude []string
// number of accesses after which to cache an object
after int
// commit objects in async manner
commitWriteback bool
// if true migration is in progress from v1 to v2
migrating bool
// mutex to protect migration bool
migMutex sync.Mutex
// retry queue for writeback cache mode to reattempt upload to backend
wbRetryCh chan ObjectInfo
// Cache stats
cacheStats *CacheStats
InnerGetObjectNInfoFn func(ctx context.Context, bucket, object string, rs *HTTPRangeSpec, h http.Header, lockType LockType, opts ObjectOptions) (gr *GetObjectReader, err error)
InnerGetObjectInfoFn func(ctx context.Context, bucket, object string, opts ObjectOptions) (objInfo ObjectInfo, err error)
InnerDeleteObjectFn func(ctx context.Context, bucket, object string, opts ObjectOptions) (objInfo ObjectInfo, err error)
InnerPutObjectFn func(ctx context.Context, bucket, object string, data *PutObjReader, opts ObjectOptions) (objInfo ObjectInfo, err error)
InnerCopyObjectFn func(ctx context.Context, srcBucket, srcObject, destBucket, destObject string, srcInfo ObjectInfo, srcOpts, dstOpts ObjectOptions) (objInfo ObjectInfo, err error)
}
func (c *cacheObjects) incHitsToMeta(ctx context.Context, dcache *diskCache, bucket, object string, size int64, eTag string, rs *HTTPRangeSpec) error {
metadata := map[string]string{"etag": eTag}
return dcache.SaveMetadata(ctx, bucket, object, metadata, size, rs, "", true)
}
// Backend metadata could have changed through server side copy - reset cache metadata if that is the case
func (c *cacheObjects) updateMetadataIfChanged(ctx context.Context, dcache *diskCache, bucket, object string, bkObjectInfo, cacheObjInfo ObjectInfo, rs *HTTPRangeSpec) error {
bkMeta := make(map[string]string, len(bkObjectInfo.UserDefined))
cacheMeta := make(map[string]string, len(cacheObjInfo.UserDefined))
for k, v := range bkObjectInfo.UserDefined {
if strings.HasPrefix(strings.ToLower(k), ReservedMetadataPrefixLower) {
// Do not need to send any internal metadata
continue
}
bkMeta[http.CanonicalHeaderKey(k)] = v
}
for k, v := range cacheObjInfo.UserDefined {
if strings.HasPrefix(strings.ToLower(k), ReservedMetadataPrefixLower) {
// Do not need to send any internal metadata
continue
}
cacheMeta[http.CanonicalHeaderKey(k)] = v
}
if !isMetadataSame(bkMeta, cacheMeta) ||
bkObjectInfo.ETag != cacheObjInfo.ETag ||
bkObjectInfo.ContentType != cacheObjInfo.ContentType ||
!bkObjectInfo.Expires.Equal(cacheObjInfo.Expires) {
return dcache.SaveMetadata(ctx, bucket, object, getMetadata(bkObjectInfo), bkObjectInfo.Size, nil, "", false)
}
return c.incHitsToMeta(ctx, dcache, bucket, object, cacheObjInfo.Size, cacheObjInfo.ETag, rs)
}
// DeleteObject clears cache entry if backend delete operation succeeds
func (c *cacheObjects) DeleteObject(ctx context.Context, bucket, object string, opts ObjectOptions) (objInfo ObjectInfo, err error) {
if objInfo, err = c.InnerDeleteObjectFn(ctx, bucket, object, opts); err != nil {
return
}
if c.isCacheExclude(bucket, object) || c.skipCache() {
return
}
dcache, cerr := c.getCacheLoc(bucket, object)
if cerr != nil {
return objInfo, cerr
}
dcache.Delete(ctx, bucket, object)
return
}
// DeleteObjects batch deletes objects in slice, and clears any cached entries
func (c *cacheObjects) DeleteObjects(ctx context.Context, bucket string, objects []ObjectToDelete, opts ObjectOptions) ([]DeletedObject, []error) {
errs := make([]error, len(objects))
objInfos := make([]ObjectInfo, len(objects))
for idx, object := range objects {
opts.VersionID = object.VersionID
objInfos[idx], errs[idx] = c.DeleteObject(ctx, bucket, object.ObjectName, opts)
}
deletedObjects := make([]DeletedObject, len(objInfos))
for idx := range errs {
if errs[idx] != nil {
continue
}
if objInfos[idx].DeleteMarker {
deletedObjects[idx] = DeletedObject{
DeleteMarker: objInfos[idx].DeleteMarker,
DeleteMarkerVersionID: objInfos[idx].VersionID,
}
continue
}
deletedObjects[idx] = DeletedObject{
ObjectName: objInfos[idx].Name,
VersionID: objInfos[idx].VersionID,
}
}
return deletedObjects, errs
}
// construct a metadata k-v map
func getMetadata(objInfo ObjectInfo) map[string]string {
metadata := make(map[string]string, len(objInfo.UserDefined)+4)
metadata["etag"] = objInfo.ETag
metadata["content-type"] = objInfo.ContentType
if objInfo.ContentEncoding != "" {
metadata["content-encoding"] = objInfo.ContentEncoding
}
if !objInfo.Expires.Equal(timeSentinel) {
metadata["expires"] = objInfo.Expires.Format(http.TimeFormat)
}
metadata["last-modified"] = objInfo.ModTime.Format(http.TimeFormat)
for k, v := range objInfo.UserDefined {
metadata[k] = v
}
return metadata
}
// marks cache hit
func (c *cacheObjects) incCacheStats(size int64) {
c.cacheStats.incHit()
c.cacheStats.incBytesServed(size)
}
func (c *cacheObjects) GetObjectNInfo(ctx context.Context, bucket, object string, rs *HTTPRangeSpec, h http.Header, lockType LockType, opts ObjectOptions) (gr *GetObjectReader, err error) {
if c.isCacheExclude(bucket, object) || c.skipCache() {
return c.InnerGetObjectNInfoFn(ctx, bucket, object, rs, h, lockType, opts)
}
var cc *cacheControl
var cacheObjSize int64
// fetch diskCache if object is currently cached or nearest available cache drive
dcache, err := c.getCacheToLoc(ctx, bucket, object)
if err != nil {
return c.InnerGetObjectNInfoFn(ctx, bucket, object, rs, h, lockType, opts)
}
cacheReader, numCacheHits, cacheErr := dcache.Get(ctx, bucket, object, rs, h, opts)
if cacheErr == nil {
cacheObjSize = cacheReader.ObjInfo.Size
if rs != nil {
if _, len, err := rs.GetOffsetLength(cacheObjSize); err == nil {
cacheObjSize = len
}
}
cc = cacheControlOpts(cacheReader.ObjInfo)
if cc != nil && (!cc.isStale(cacheReader.ObjInfo.ModTime) ||
cc.onlyIfCached) {
// This is a cache hit, mark it so
bytesServed := cacheReader.ObjInfo.Size
if rs != nil {
if _, len, err := rs.GetOffsetLength(bytesServed); err == nil {
bytesServed = len
}
}
c.cacheStats.incHit()
c.cacheStats.incBytesServed(bytesServed)
c.incHitsToMeta(ctx, dcache, bucket, object, cacheReader.ObjInfo.Size, cacheReader.ObjInfo.ETag, rs)
return cacheReader, nil
}
if cc != nil && cc.noStore {
cacheReader.Close()
c.cacheStats.incMiss()
bReader, err := c.InnerGetObjectNInfoFn(ctx, bucket, object, rs, h, lockType, opts)
bReader.ObjInfo.CacheLookupStatus = CacheHit
bReader.ObjInfo.CacheStatus = CacheMiss
return bReader, err
}
}
objInfo, err := c.InnerGetObjectInfoFn(ctx, bucket, object, opts)
if backendDownError(err) && cacheErr == nil {
c.incCacheStats(cacheObjSize)
return cacheReader, nil
} else if err != nil {
if cacheErr == nil {
cacheReader.Close()
}
if _, ok := err.(ObjectNotFound); ok {
if cacheErr == nil {
// Delete cached entry if backend object
// was deleted.
dcache.Delete(ctx, bucket, object)
}
}
c.cacheStats.incMiss()
return nil, err
}
if !objInfo.IsCacheable() {
if cacheErr == nil {
cacheReader.Close()
}
c.cacheStats.incMiss()
return c.InnerGetObjectNInfoFn(ctx, bucket, object, rs, h, lockType, opts)
}
// skip cache for objects with locks
objRetention := objectlock.GetObjectRetentionMeta(objInfo.UserDefined)
legalHold := objectlock.GetObjectLegalHoldMeta(objInfo.UserDefined)
if objRetention.Mode.Valid() || legalHold.Status.Valid() {
if cacheErr == nil {
cacheReader.Close()
}
c.cacheStats.incMiss()
return c.InnerGetObjectNInfoFn(ctx, bucket, object, rs, h, lockType, opts)
}
if cacheErr == nil {
// if ETag matches for stale cache entry, serve from cache
if cacheReader.ObjInfo.ETag == objInfo.ETag {
// Update metadata in case server-side copy might have changed object metadata
c.updateMetadataIfChanged(ctx, dcache, bucket, object, objInfo, cacheReader.ObjInfo, rs)
c.incCacheStats(cacheObjSize)
return cacheReader, nil
}
cacheReader.Close()
// Object is stale, so delete from cache
dcache.Delete(ctx, bucket, object)
}
// Reaching here implies cache miss
c.cacheStats.incMiss()
bkReader, bkErr := c.InnerGetObjectNInfoFn(ctx, bucket, object, rs, h, lockType, opts)
if bkErr != nil {
return bkReader, bkErr
}
// If object has less hits than configured cache after, just increment the hit counter
// but do not cache it.
if numCacheHits < c.after {
c.incHitsToMeta(ctx, dcache, bucket, object, objInfo.Size, objInfo.ETag, rs)
return bkReader, bkErr
}
// Record if cache has a hit that was invalidated by ETag verification
if cacheErr == nil {
bkReader.ObjInfo.CacheLookupStatus = CacheHit
}
// Check if we can add it without exceeding total cache size.
if !dcache.diskSpaceAvailable
8BD0
(objInfo.Size) {
return bkReader, bkErr
}
if rs != nil && !dcache.enableRange {
go func() {
// if range caching is disabled, download entire object.
rs = nil
// fill cache in the background for range GET requests
bReader, bErr := c.InnerGetObjectNInfoFn(GlobalContext, bucket, object, rs, h, lockType, opts)
if bErr != nil {
return
}
defer bReader.Close()
oi, _, _, err := dcache.statRange(GlobalContext, bucket, object, rs)
// avoid cache overwrite if another background routine filled cache
if err != nil || oi.ETag != bReader.ObjInfo.ETag {
// use a new context to avoid locker prematurely timing out operation when the GetObjectNInfo returns.
dcache.Put(GlobalContext, bucket, object, bReader, bReader.ObjInfo.Size, rs, ObjectOptions{
UserDefined: getMetadata(bReader.ObjInfo),
}, false)
return
}
}()
return bkReader, bkErr
}
// Initialize pipe.
pipeReader, pipeWriter := io.Pipe()
teeReader := io.TeeReader(bkReader, pipeWriter)
userDefined := getMetadata(bkReader.ObjInfo)
go func() {
_, putErr := dcache.Put(ctx, bucket, object,
io.LimitReader(pipeReader, bkReader.ObjInfo.Size),
bkReader.ObjInfo.Size, rs, ObjectOptions{
UserDefined: userDefined,
}, false)
// close the write end of the pipe, so the error gets
// propagated to getObjReader
pipeWriter.CloseWithError(putErr)
}()
cleanupBackend := func() { bkReader.Close() }
cleanupPipe := func() { pipeWriter.Close() }
return NewGetObjectReaderFromReader(teeReader, bkReader.ObjInfo, opts, cleanupBackend, cleanupPipe)
}
// Returns ObjectInfo from cache if available.
func (c *cacheObjects) GetObjectInfo(ctx context.Context, bucket, object string, opts ObjectOptions) (ObjectInfo, error) {
getObjectInfoFn := c.InnerGetObjectInfoFn
if c.isCacheExclude(bucket, object) || c.skipCache() {
return getObjectInfoFn(ctx, bucket, object, opts)
}
// fetch diskCache if object is currently cached or nearest available cache drive
dcache, err := c.getCacheToLoc(ctx, bucket, object)
if err != nil {
return getObjectInfoFn(ctx, bucket, object, opts)
}
var cc *cacheControl
// if cache control setting is valid, avoid HEAD operation to backend
cachedObjInfo, _, cerr := dcache.Stat(ctx, bucket, object)
if cerr == nil {
cc = cacheControlOpts(cachedObjInfo)
if cc == nil || (cc != nil && !cc.isStale(cachedObjInfo.ModTime)) {
// This is a cache hit, mark it so
c.cacheStats.incHit()
return cachedObjInfo, nil
}
}
objInfo, err := getObjectInfoFn(ctx, bucket, object, opts)
if err != nil {
if _, ok := err.(ObjectNotFound); ok {
// Delete the cached entry if backend object was deleted.
dcache.Delete(ctx, bucket, object)
c.cacheStats.incMiss()
return ObjectInfo{}, err
}
if !backendDownError(err) {
c.cacheStats.incMiss()
return ObjectInfo{}, err
}
if cerr == nil {
// This is a cache hit, mark it so
c.cacheStats.incHit()
return cachedObjInfo, nil
}
c.cacheStats.incMiss()
return ObjectInfo{}, BackendDown{}
}
// Reaching here implies cache miss
c.cacheStats.incMiss()
// when backend is up, do a sanity check on cached object
if cerr != nil {
return objInfo, nil
}
if cachedObjInfo.ETag != objInfo.ETag {
// Delete the cached entry if the backend object was replaced.
dcache.Delete(ctx, bucket, object)
}
return objInfo, nil
}
// CopyObject reverts to backend after evicting any stale cache entries
func (c *cacheObjects) CopyObject(ctx context.Context, srcBucket, srcObject, dstBucket, dstObject string, srcInfo ObjectInfo, srcOpts, dstOpts ObjectOptions) (objInfo ObjectInfo, err error) {
copyObjectFn := c.InnerCopyObjectFn
if c.isCacheExclude(srcBucket, srcObject) || c.skipCache() {
return copyObjectFn(ctx, srcBucket, srcObject, dstBucket, dstObject, srcInfo, srcOpts, dstOpts)
}
if srcBucket != dstBucket || srcObject != dstObject {
return copyObjectFn(ctx, srcBucket, srcObject, dstBucket, dstObject, srcInfo, srcOpts, dstOpts)
}
// fetch diskCache if object is currently cached or nearest available cache drive
dcache, err := c.getCacheToLoc(ctx, srcBucket, srcObject)
if err != nil {
return copyObjectFn(ctx, srcBucket, srcObject, dstBucket, dstObject, srcInfo, srcOpts, dstOpts)
}
// if currently cached, evict old entry and revert to backend.
if cachedObjInfo, _, cerr := dcache.Stat(ctx, srcBucket, srcObject); cerr == nil {
cc := cacheControlOpts(cachedObjInfo)
if cc == nil || !cc.isStale(cachedObjInfo.ModTime) {
dcache.Delete(ctx, srcBucket, srcObject)
}
}
return copyObjectFn(ctx, srcBucket, srcObject, dstBucket, dstObject, srcInfo, srcOpts, dstOpts)
}
// StorageInfo - returns underlying storage statistics.
func (c *cacheObjects) StorageInfo(ctx context.Context) (cInfo CacheStorageInfo) {
var total, free uint64
for _, cache := range c.cache {
if cache == nil {
continue
}
info, err := getDiskInfo(cache.dir)
logger.GetReqInfo(ctx).AppendTags("cachePath", cache.dir)
logger.LogIf(ctx, err)
total += info.Total
free += info.Free
}
return CacheStorageInfo{
Total: total,
Free: free,
}
}
// CacheStats - returns underlying storage statistics.
func (c *cacheObjects) CacheStats() (cs *CacheStats) {
return c.cacheStats
}
// skipCache() returns true if cache migration is in progress
func (c *cacheObjects) skipCache() bool {
c.migMutex.Lock()
defer c.migMutex.Unlock()
return c.migrating
}
// Returns true if object should be excluded from cache
func (c *cacheObjects) isCacheExclude(bucket, object string) bool {
// exclude directories from cache
if strings.HasSuffix(object, SlashSeparator) {
return true
}
for _, pattern := range c.exclude {
matchStr := fmt.Sprintf("%s/%s", bucket, object)
if ok := wildcard.MatchSimple(pattern, matchStr); ok {
return true
}
}
return false
}
// choose a cache deterministically based on hash of bucket,object. The hash index is treated as
// a hint. In the event that the cache drive at hash index is offline, treat the list of cache drives
// as a circular buffer and walk through them starting at hash index until an online drive is found.
func (c *cacheObjects) getCacheLoc(bucket, object string) (*diskCache, error) {
index := c.hashIndex(bucket, object)
numDisks := len(c.cache)
for k := 0; k < numDisks; k++ {
i := (index + k) % numDisks
if c.cache[i] == nil {
continue
}
if c.cache[i].IsOnline() {
return c.cache[i], nil
}
}
return nil, errDiskNotFound
}
// get cache disk where object is currently cached for a GET operation. If object does not exist at that location,
// treat the list of cache drives as a circular buffer and walk through them starting at hash index
// until an online drive is found.If object is not found, fall back to the first online cache drive
// closest to the hash index, so that object can be re-cached.
func (c *cacheObjects) getCacheToLoc(ctx context.Context, bucket, object string) (*diskCache, error) {
index := c.hashIndex(bucket, object)
numDisks := len(c.cache)
// save first online cache disk closest to the hint index
var firstOnlineDisk *diskCache
for k := 0; k < numDisks; k++ {
i := (index + k) % numDisks
if c.cache[i] == nil {
continue
}
if c.cache[i].IsOnline() {
if firstOnlineDisk == nil {
firstOnlineDisk = c.cache[i]
}
if c.cache[i].Exists(ctx, bucket, object) {
return c.cache[i], nil
}
}
}
if firstOnlineDisk != nil {
return firstOnlineDisk, nil
}
return nil, errDiskNotFound
}
// Compute a unique hash sum for bucket and object
func (c *cacheObjects) hashIndex(bucket, object string) int {
return crcHashMod(pathJoin(bucket, object), len(c.cache))
}
// newCache initializes the cacheFSObjects for the "drives" specified in config.json
// or the global env overrides.
func newCache(config cache.Config) ([]*diskCache, bool, error) {
var caches []*diskCache
ctx := logger.SetReqInfo(GlobalContext, &logger.ReqInfo{})
formats, migrating, err := loadAndValidateCacheFormat(ctx, config.Drives)
if err != nil {
return nil, false, err
}
for i, dir := range config.Drives {
// skip diskCache creation for cache drives missing a format.json
if formats[i] == nil {
caches = append(caches, nil)
continue
}
if err := checkAtimeSupport(dir); err != nil {
return nil, false, errors.New("Atime support required for disk caching")
}
cache, err := newDiskCache(ctx, dir, config)
if err != nil {
return nil, false, err
}
caches = append(caches, cache)
}
return caches, migrating, nil
}
func (c *cacheObjects) migrateCacheFromV1toV2(ctx context.Context) {
logStartupMessage(color.Blue("Cache migration initiated ...."))
g := errgroup.WithNErrs(len(c.cache))
for index, dc := range c.cache {
if dc == nil {
continue
}
index := index
g.Go(func() error {
// start migration from V1 to V2
return migrateOldCache(ctx, c.cache[index])
}, index)
}
errCnt := 0
for _, err := range g.Wait() {
if err != nil {
errCnt++
logger.LogIf(ctx, err)
continue
}
}
if errCnt > 0 {
return
}
// update migration status
c.migMutex.Lock()
defer c.migMutex.Unlock()
c.migrating = false
logStartupMessage(color.Blue("Cache migration completed successfully."))
}
// PutObject - caches the uploaded object for single Put operations
func (c *cacheObjects) PutObject(ctx context.Context, bucket, object string, r *PutObjReader, opts ObjectOptions) (objInfo ObjectInfo, err error) {
putObjectFn := c.InnerPutObjectFn
dcache, err := c.getCacheToLoc(ctx, bucket, object)
if err != nil {
// disk cache could not be located,execute backend call.
return putObjectFn(ctx, bucket, object, r, opts)
}
size := r.Size()
if c.skipCache() {
return putObjectFn(ctx, bucket, object, r, opts)
}
// fetch from backend if there is no space on cache drive
if !dcache.diskSpaceAvailable(size) {
return putObjectFn(ctx, bucket, object, r, opts)
}
if opts.ServerSideEncryption != nil {
dcache.Delete(ctx, bucket, object)
return putObjectFn(ctx, bucket, object, r, opts)
}
// skip cache for objects with locks
objRetention := objectlock.GetObjectRetentionMeta(opts.UserDefined)
legalHold := objectlock.GetObjectLegalHoldMeta(opts.UserDefined)
if objRetention.Mode.Valid() || legalHold.Status.Valid() {
dcache.Delete(ctx, bucket, object)
return putObjectFn(ctx, bucket, object, r, opts)
}
// fetch from backend if cache exclude pattern or cache-control
// directive set to exclude
if c.isCacheExclude(bucket, object) {
dcache.Delete(ctx, bucket, object)
return putObjectFn(ctx, bucket, object, r, opts)
}
if c.commitWriteback {
oi, err := dcache.Put(ctx, bucket, object, r, r.Size(), nil, opts, false)
if err != nil {
return ObjectInfo{}, err
}
go c.uploadObject(GlobalContext, oi)
return oi, nil
}
objInfo, err = putObjectFn(ctx, bucket, object, r, opts)
if err == nil {
go func() {
// fill cache in the background
bReader, bErr := c.InnerGetObjectNInfoFn(GlobalContext, bucket, object, nil, http.Header{}, readLock, ObjectOptions{})
if bErr != nil {
return
}
defer bReader.Close()
oi, _, err := dcache.Stat(GlobalContext, bucket, object)
// avoid cache overwrite if another background routine filled cache
if err != nil || oi.ETag != bReader.ObjInfo.ETag {
dcache.Put(GlobalContext, bucket, object, bReader, bReader.ObjInfo.Size, nil, ObjectOptions{UserDefined: getMetadata(bReader.ObjInfo)}, false)
}
}()
}
return objInfo, err
}
// upload cached object to backend in async commit mode.
func (c *cacheObjects) uploadObject(ctx context.Context, oi ObjectInfo) {
dcache, err := c.getCacheToLoc(ctx, oi.Bucket, oi.Name)
if err != nil {
// disk cache could not be located.
logger.LogIf(ctx, fmt.Errorf("Could not upload %s/%s to backend: %w", oi.Bucket, oi.Name, err))
return
}
cReader, _, bErr := dcache.Get(ctx, oi.Bucket, oi.Name, nil, http.Header{}, ObjectOptions{})
if bErr != nil {
return
}
defer cReader.Close()
if cReader.ObjInfo.ETag != oi.ETag {
return
}
st := cacheCommitStatus(oi.UserDefined[writeBackStatusHeader])
if st == CommitComplete || st.String() == "" {
return
}
hashReader, err := hash.NewReader(cReader, oi.Size, "", "", oi.Size)
if err != nil {
return
}
var opts ObjectOptions
opts.UserDefined = make(map[string]string)
opts.UserDefined[xhttp.ContentMD5] = oi.UserDefined["content-md5"]
objInfo, err := c.InnerPutObjectFn(ctx, oi.Bucket, oi.Name, NewPutObjReader(hashReader), opts)
wbCommitStatus := CommitComplete
if err != nil {
wbCommitStatus = CommitFailed
}
meta := cloneMSS(cReader.ObjInfo.UserDefined)
retryCnt := 0
if wbCommitStatus == CommitFailed {
retryCnt, _ = strconv.Atoi(meta[writeBackRetryHeader])
retryCnt++
meta[writeBackRetryHeader] = strconv.Itoa(retryCnt)
} else {
delete(meta, writeBackRetryHeader)
}
meta[writeBackStatusHeader] = wbCommitStatus.String()
meta["etag"] = oi.ETag
dcache.SaveMetadata(ctx, oi.Bucket, oi.Name, meta, objInfo.Size, nil, "", false)
if retryCnt > 0 {
// slow down retries
time.Sleep(time.Second * time.Duration(retryCnt%10+1))
c.queueWritebackRetry(oi)
}
}
func (c *cacheObjects) queueWritebackRetry(oi ObjectInfo) {
select {
case c.wbRetryCh <- oi:
c.uploadObject(GlobalContext, oi)
default:
}
}
// Returns cacheObjects for use by Server.
func newServerCacheObjects(ctx context.Context, config cache.Config) (CacheObjectLayer, error) {
// list of disk caches for cache "drives" specified in config.json or MINIO_CACHE_DRIVES env var.
cache, migrateSw, err := newCache(config)
if err != nil {
return nil, err
}
c := &cacheObjects{
cache: cache,
exclude: config.Exclude,
after: config.After,
migrating: migrateSw,
migMutex: sync.Mutex{},
commitWriteback: config.CommitWriteback,
cacheStats: newCacheStats(),
InnerGetObjectInfoFn: func(ctx context.Context, bucket, object string, opts ObjectOptions) (ObjectInfo, error) {
return newObjectLayerFn().GetObjectInfo(ctx, bucket, object, opts)
},
InnerGetObjectNInfoFn: func(ctx context.Context, bucket, object string, rs *HTTPRangeSpec, h http.Header, lockType LockType, opts ObjectOptions) (gr *GetObjectReader, err error) {
return newObjectLayerFn().GetObjectNInfo(ctx, bucket, object, rs, h, lockType, opts)
},
InnerDeleteObjectFn: func(ctx context.Context, bucket, object string, opts ObjectOptions) (ObjectInfo, error) {
return newObjectLayerFn().DeleteObject(ctx, bucket, object, opts)
},
InnerPutObjectFn: func(ctx context.Context, bucket, object string, data *PutObjReader, opts ObjectOptions) (objInfo ObjectInfo, err error) {
return newObjectLayerFn().PutObject(ctx, bucket, object, data, opts)
},
InnerCopyObjectFn: func(ctx context.Context, srcBucket, srcObject, destBucket, destObject string, srcInfo ObjectInfo, srcOpts, dstOpts ObjectOptions) (objInfo ObjectInfo, err error) {
return newObjectLayerFn().CopyObject(ctx, srcBucket, srcObject, destBucket, destObject, srcInfo, srcOpts, dstOpts)
},
}
c.cacheStats.GetDiskStats = func() []CacheDiskStats {
cacheDiskStats := make([]CacheDiskStats, len(c.cache))
for i := range c.cache {
dcache := c.cache[i]
cacheDiskStats[i] = CacheDiskStats{}
if dcache != nil {
info, err := getDiskInfo(dcache.dir)
logger.LogIf(ctx, err)
cacheDiskStats[i].UsageSize = info.Used
cacheDiskStats[i].TotalCapacity = info.Total
cacheDiskStats[i].Dir = dcache.stats.Dir
atomic.StoreInt32(&cacheDiskStats[i].UsageState, atomic.LoadInt32(&dcache.stats.UsageState))
atomic.StoreUint64(&cacheDiskStats[i].UsagePercent, atomic.LoadUint64(&dcache.stats.UsagePercent))
}
}
return cacheDiskStats
}
if migrateSw {
go c.migrateCacheFromV1toV2(ctx)
}
go c.gc(ctx)
if c.commitWriteback {
c.wbRetryCh = make(chan ObjectInfo, 10000)
go func() {
<-GlobalContext.Done()
close(c.wbRetryCh)
}()
go c.queuePendingWriteback(ctx)
}
return c, nil
}
func (c *cacheObjects) gc(ctx context.Context) {
ticker := time.NewTicker(cacheGCInterval)
defer ticker.Stop()
for {
select {
case <-ctx.Done():
return
case <-ticker.C:
if c.migrating {
continue
}
for _, dcache := range c.cache {
if dcache != nil {
// Check if there is disk.
// Will queue a GC scan if at high watermark.
dcache.diskSpaceAvailable(0)
}
}
}
}
}
// queues any pending or failed async commits when server restarts
func (c *cacheObjects) queuePendingWriteback(ctx context.Context) {
for _, dcache := range c.cache {
if dcache != nil {
for {
select {
case <-ctx.Done():
return
case oi, ok := <-dcache.retryWritebackCh:
if !ok {
goto next
}
c.queueWritebackRetry(oi)
default:
time.Sleep(time.Second * 1)
}
}
next:
}
}
}