Deadlock fix and cleanups

logger.go

@@ -6,7 +6,8 @@ import (
 	"os"
 )
 
-var logger = log.New(os.Stderr, "", log.Ltime)
+// set in main()
+var logger *log.Logger
 
 func debugln(vals ...interface{}) {
 	s := fmt.Sprintln(vals...)

main.go

@@ -97,8 +97,11 @@ func main() {
 		runtime.GOMAXPROCS(runtime.NumCPU())
 	}
 
+	log.SetOutput(os.Stderr)
+	logger = log.New(os.Stderr, "", log.Flags())
 	if len(opts.Debug.TraceModel) > 0 || opts.Debug.LogSource {
-		logger = log.New(os.Stderr, "", log.Lshortfile|log.Ldate|log.Ltime|log.Lmicroseconds)
+		log.SetFlags(log.Lshortfile | log.Ldate | log.Ltime | log.Lmicroseconds)
+		logger.SetFlags(log.Lshortfile | log.Ldate | log.Ltime | log.Lmicroseconds)
 	}
 	opts.ConfDir = expandTilde(opts.ConfDir)
 

model/filemonitor.go

@@ -29,7 +29,10 @@ func (m *fileMonitor) FileBegins(cc <-chan content) error {
 	dir := path.Dir(tmp)
 	_, err := os.Stat(dir)
 	if err != nil && os.IsNotExist(err) {
-		os.MkdirAll(dir, 0777)
+		err = os.MkdirAll(dir, 0777)
+		if err != nil {
+			return err
+		}
 	}
 
 	outFile, err := os.Create(tmp)
@@ -106,6 +109,13 @@ func (m *fileMonitor) FileDone() error {
 	tmp := tempName(m.path, m.global.Modified)
 	defer os.Remove(tmp)
 
+	if m.copyError != nil {
+		return m.copyError
+	}
+	if m.writeError != nil {
+		return m.writeError
+	}
+
 	err := hashCheck(tmp, m.global.Blocks)
 	if err != nil {
 		return fmt.Errorf("%s: %s (tmp) (deleting)", path.Base(m.name), err.Error())

model/filequeue.go

@@ -7,20 +7,16 @@ import (
 	"time"
 )
 
-type Resolver interface {
-	WhoHas(string) []string
-}
-
 type Monitor interface {
 	FileBegins(<-chan content) error
 	FileDone() error
 }
 
 type FileQueue struct {
-	resolver Resolver
-	files    queuedFileList
-	lock     sync.Mutex
-	sorted   bool
+	files        queuedFileList
+	lock         sync.Mutex
+	sorted       bool
+	availability map[string][]string
 }
 
 type queuedFile struct {
@@ -92,32 +88,28 @@ func (q *FileQueue) Get(nodeID string) (queuedBlock, bool) {
 	}
 
 	for i := range q.files {
-		if time.Since(q.files[i].nodesChecked) > 5*time.Second {
-			// Refresh node list every now and then
-			q.files[i].nodes = q.resolver.WhoHas(q.files[i].name)
-		}
+		qf := &q.files[i]
 
-		if len(q.files[i].nodes) == 0 {
+		if len(q.availability[qf.name]) == 0 {
 			// Noone has the file we want; abort.
-			if q.files[i].remaining != len(q.files[i].blocks) {
+			if qf.remaining != len(qf.blocks) {
 				// We have already started on this file; close it down
-				close(q.files[i].channel)
-				if mon := q.files[i].monitor; mon != nil {
+				close(qf.channel)
+				if mon := qf.monitor; mon != nil {
 					mon.FileDone()
 				}
 			}
-			q.deleteIndex(i)
+			q.deleteAt(i)
 			return queuedBlock{}, false
 		}
 
-		qf := q.files[i]
-		for _, ni := range qf.nodes {
+		for _, ni := range q.availability[qf.name] {
 			// Find and return the next block in the queue
 			if ni == nodeID {
 				for j, b := range qf.blocks {
 					if !qf.activeBlocks[j] {
-						q.files[i].activeBlocks[j] = true
-						q.files[i].given++
+						qf.activeBlocks[j] = true
+						qf.given++
 						return queuedBlock{
 							name:  qf.name,
 							block: b,
@@ -142,29 +134,31 @@ func (q *FileQueue) Done(file string, offset int64, data []byte) {
 		offset: offset,
 		data:   data,
 	}
-	for i, qf := range q.files {
+	for i := range q.files {
+		qf := &q.files[i]
+
 		if qf.name == file {
 			if qf.monitor != nil && qf.remaining == len(qf.blocks) {
 				err := qf.monitor.FileBegins(qf.channel)
 				if err != nil {
 					log.Printf("WARNING: %s: %v (not synced)", qf.name, err)
-					q.deleteIndex(i)
+					q.deleteAt(i)
 					return
 				}
 			}
 
 			qf.channel <- c
-			q.files[i].remaining--
+			qf.remaining--
 
-			if q.files[i].remaining == 0 {
+			if qf.remaining == 0 {
 				close(qf.channel)
-				q.deleteIndex(i)
 				if qf.monitor != nil {
 					err := qf.monitor.FileDone()
 					if err != nil {
 						log.Printf("WARNING: %s: %v", qf.name, err)
 					}
 				}
+				q.deleteAt(i)
 			}
 			return
 		}
@@ -194,6 +188,24 @@ func (q *FileQueue) QueuedFiles() (files []string) {
 	return
 }
 
-func (q *FileQueue) deleteIndex(i int) {
+func (q *FileQueue) deleteAt(i int) {
 	q.files = q.files[:i+copy(q.files[i:], q.files[i+1:])]
 }
+
+func (q *FileQueue) SetAvailable(file, node string) {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+	if q.availability == nil {
+		q.availability = make(map[string][]string)
+	}
+	q.availability[file] = []string{node}
+}
+
+func (q *FileQueue) AddAvailable(file, node string) {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+	if q.availability == nil {
+		q.availability = make(map[string][]string)
+	}
+	q.availability[file] = append(q.availability[file], node)
+}

model/model.go

@@ -94,7 +94,6 @@ func NewModel(dir string) *Model {
 		fileWasSuppressed: make(map[string]int),
 		dq:                make(chan File),
 	}
-	m.fq.resolver = m
 
 	go m.broadcastIndexLoop()
 	return m
@@ -618,13 +617,16 @@ func (m *Model) recomputeGlobal() {
 	}
 
 	var highestMod int64
-	for _, fs := range m.remote {
+	for nodeID, fs := range m.remote {
 		for n, nf := range fs {
 			if lf, ok := newGlobal[n]; !ok || nf.NewerThan(lf) {
 				newGlobal[n] = nf
+				m.fq.SetAvailable(n, nodeID)
 				if nf.Modified > highestMod {
 					highestMod = nf.Modified
 				}
+			} else if lf.Equals(nf) {
+				m.fq.AddAvailable(n, nodeID)
 			}
 		}
 	}
@@ -690,8 +692,14 @@ func (m *Model) recomputeNeed() {
 	}
 }
 
-// Must be called with the read lock held.
 func (m *Model) WhoHas(name string) []string {
+	m.RLock()
+	defer m.RUnlock()
+	return m.whoHas(name)
+}
+
+// Must be called with the read lock held.
+func (m *Model) whoHas(name string) []string {
 	var remote []string
 
 	gf := m.global[name]