fixed deadlock caused by attempt to write asynchronous pack data

repo/object_manager.go

@@ -71,7 +71,7 @@ func (r *ObjectManager) NewWriter(opt WriterOptions) ObjectWriter {
 		splitter:       r.newSplitter(),
 		description:    opt.Description,
 		prefix:         opt.BlockNamePrefix,
-		disablePacking: opt.disablePacking,
+		isPackInternalObject: opt.isPackInternalObject,
 		packGroup:      opt.PackGroup,
 	}
 
@@ -196,7 +196,7 @@ func newObjectManager(s blob.Storage, f config.RepositoryObjectFormat, opts *Opt
 // hashEncryptAndWrite computes hash of a given buffer, optionally encrypts and writes it to storage.
 // The write is not guaranteed to complete synchronously in case write-back is used, but by the time
 // Repository.Close() returns all writes are guaranteed be over.
-func (r *ObjectManager) hashEncryptAndWrite(packGroup string, buffer *bytes.Buffer, prefix string, disablePacking bool) (ObjectID, error) {
+func (r *ObjectManager) hashEncryptAndWrite(packGroup string, buffer *bytes.Buffer, prefix string, isPackInternalObject bool) (ObjectID, error) {
 	var data []byte
 	if buffer != nil {
 		data = buffer.Bytes()
@@ -208,7 +208,7 @@ func (r *ObjectManager) hashEncryptAndWrite(packGroup string, buffer *bytes.Buff
 	atomic.AddInt32(&r.stats.HashedBlocks, 1)
 	atomic.AddInt64(&r.stats.HashedBytes, int64(len(data)))
 
-	if !disablePacking && r.packMgr.enabled() && r.format.MaxPackedContentLength > 0 && len(data) <= r.format.MaxPackedContentLength {
+	if !isPackInternalObject && r.packMgr.enabled() && r.format.MaxPackedContentLength > 0 && len(data) <= r.format.MaxPackedContentLength {
 		packOID, err := r.packMgr.AddToPack(packGroup, prefix+objectID.StorageBlock, data)
 		return packOID, err
 	}

repo/object_writer.go

@@ -59,8 +59,8 @@ type objectWriter struct {
 	blockTracker *blockTracker
 	splitter     objectSplitter
 
-	disablePacking bool
-	packGroup      string
+	isPackInternalObject bool
+	packGroup            string
 
 	pendingBlocksWG sync.WaitGroup
 
@@ -102,7 +102,7 @@ func (w *objectWriter) flushBuffer() error {
 	w.buffer.Reset()
 
 	do := func() {
-		objectID, err := w.repo.hashEncryptAndWrite(w.packGroup, &b2, w.prefix, w.disablePacking)
+		objectID, err := w.repo.hashEncryptAndWrite(w.packGroup, &b2, w.prefix, w.isPackInternalObject)
 		w.repo.trace("OBJECT_WRITER(%q) stored %v (%v bytes)", w.description, objectID, length)
 		if err != nil {
 			w.err.add(fmt.Errorf("error when flushing chunk %d of %s: %v", chunkID, w.description, err))
@@ -113,7 +113,9 @@ func (w *objectWriter) flushBuffer() error {
 		w.blockIndex[chunkID].Object = objectID
 	}
 
-	if w.repo.async {
+	// When writing pack internal object don't use asynchronous write, since we're already under the semaphore
+	// and it may lead to a deadlock.
+	if w.repo.async && !w.isPackInternalObject {
 		w.repo.writeBackSemaphore.Lock()
 		w.pendingBlocksWG.Add(1)
 		w.repo.writeBackWG.Add(1)
@@ -153,8 +155,8 @@ func (w *objectWriter) Result() (ObjectID, error) {
 		blockTracker: w.blockTracker,
 		splitter:     w.repo.newSplitter(),
 
-		disablePacking: w.disablePacking,
-		packGroup:      w.packGroup,
+		isPackInternalObject: w.isPackInternalObject,
+		packGroup:            w.packGroup,
 	}
 
 	jw := jsonstream.NewWriter(iw, indirectStreamType)
@@ -180,6 +182,6 @@ type WriterOptions struct {
 	Description     string
 	PackGroup       string
 
-	splitter       objectSplitter
-	disablePacking bool
+	splitter             objectSplitter
+	isPackInternalObject bool
 }

repo/pack_manager.go

@@ -176,10 +176,10 @@ func (p *packManager) flushPackIndexesLocked() error {
 
 func (p *packManager) writePackIndexes(ndx packIndexes) error {
 	w := p.objectManager.NewWriter(WriterOptions{
-		disablePacking:  true,
-		Description:     "pack index",
-		BlockNamePrefix: packObjectPrefix,
-		splitter:        newNeverSplitter(),
+		isPackInternalObject: true,
+		Description:          "pack index",
+		BlockNamePrefix:      packObjectPrefix,
+		splitter:             newNeverSplitter(),
 	})
 	defer w.Close()
 
@@ -210,9 +210,9 @@ func (p *packManager) finishPackLocked(g *packInfo) error {
 		return nil
 	}
 	w := p.objectManager.NewWriter(WriterOptions{
-		Description:    fmt.Sprintf("pack:%v", g.currentPackID),
-		splitter:       newNeverSplitter(),
-		disablePacking: true,
+		Description:          fmt.Sprintf("pack:%v", g.currentPackID),
+		splitter:             newNeverSplitter(),
+		isPackInternalObject: true,
 	})
 	defer w.Close()