Fine grained locking

model/filequeue.go

@@ -14,9 +14,10 @@ type Monitor interface {
 
 type FileQueue struct {
 	files        queuedFileList
-	lock         sync.Mutex
 	sorted       bool
+	fmut         sync.Mutex // protects files and sorted
 	availability map[string][]string
+	amut         sync.Mutex // protects availability
 }
 
 type queuedFile struct {
@@ -57,8 +58,14 @@ type queuedBlock struct {
 }
 
 func (q *FileQueue) Add(name string, blocks []Block, monitor Monitor) {
-	q.lock.Lock()
-	defer q.lock.Unlock()
+	q.fmut.Lock()
+	defer q.fmut.Unlock()
+
+	for _, f := range q.files {
+		if f.name == name {
+			panic("re-adding added file " + f.name)
+		}
+	}
 
 	q.files = append(q.files, queuedFile{
 		name:         name,
@@ -72,15 +79,15 @@ func (q *FileQueue) Add(name string, blocks []Block, monitor Monitor) {
 }
 
 func (q *FileQueue) Len() int {
-	q.lock.Lock()
-	defer q.lock.Unlock()
+	q.fmut.Lock()
+	defer q.fmut.Unlock()
 
 	return len(q.files)
 }
 
 func (q *FileQueue) Get(nodeID string) (queuedBlock, bool) {
-	q.lock.Lock()
-	defer q.lock.Unlock()
+	q.fmut.Lock()
+	defer q.fmut.Unlock()
 
 	if !q.sorted {
 		sort.Sort(q.files)
@@ -90,7 +97,11 @@ func (q *FileQueue) Get(nodeID string) (queuedBlock, bool) {
 	for i := range q.files {
 		qf := &q.files[i]
 
-		if len(q.availability[qf.name]) == 0 {
+		q.amut.Lock()
+		av := q.availability[qf.name]
+		q.amut.Unlock()
+
+		if len(av) == 0 {
 			// Noone has the file we want; abort.
 			if qf.remaining != len(qf.blocks) {
 				// We have already started on this file; close it down
@@ -103,7 +114,7 @@ func (q *FileQueue) Get(nodeID string) (queuedBlock, bool) {
 			return queuedBlock{}, false
 		}
 
-		for _, ni := range q.availability[qf.name] {
+		for _, ni := range av {
 			// Find and return the next block in the queue
 			if ni == nodeID {
 				for j, b := range qf.blocks {
@@ -127,8 +138,8 @@ func (q *FileQueue) Get(nodeID string) (queuedBlock, bool) {
 }
 
 func (q *FileQueue) Done(file string, offset int64, data []byte) {
-	q.lock.Lock()
-	defer q.lock.Unlock()
+	q.fmut.Lock()
+	defer q.fmut.Unlock()
 
 	c := content{
 		offset: offset,
@@ -167,8 +178,8 @@ func (q *FileQueue) Done(file string, offset int64, data []byte) {
 }
 
 func (q *FileQueue) Queued(file string) bool {
-	q.lock.Lock()
-	defer q.lock.Unlock()
+	q.fmut.Lock()
+	defer q.fmut.Unlock()
 
 	for _, qf := range q.files {
 		if qf.name == file {
@@ -179,8 +190,8 @@ func (q *FileQueue) Queued(file string) bool {
 }
 
 func (q *FileQueue) QueuedFiles() (files []string) {
-	q.lock.Lock()
-	defer q.lock.Unlock()
+	q.fmut.Lock()
+	defer q.fmut.Unlock()
 
 	for _, qf := range q.files {
 		files = append(files, qf.name)
@@ -202,8 +213,9 @@ func (q *FileQueue) deleteFile(n string) {
 }
 
 func (q *FileQueue) SetAvailable(file, node string) {
-	q.lock.Lock()
-	defer q.lock.Unlock()
+	q.amut.Lock()
+	defer q.amut.Unlock()
+
 	if q.availability == nil {
 		q.availability = make(map[string][]string)
 	}
@@ -211,8 +223,9 @@ func (q *FileQueue) SetAvailable(file, node string) {
 }
 
 func (q *FileQueue) AddAvailable(file, node string) {
-	q.lock.Lock()
-	defer q.lock.Unlock()
+	q.amut.Lock()
+	defer q.amut.Unlock()
+
 	if q.availability == nil {
 		q.availability = make(map[string][]string)
 	}
@@ -220,8 +233,9 @@ func (q *FileQueue) AddAvailable(file, node string) {
 }
 
 func (q *FileQueue) RemoveAvailable(toRemove string) {
-	q.lock.Lock()
-	defer q.lock.Unlock()
+	q.amut.Lock()
+	defer q.amut.Unlock()
+
 	for file, nodes := range q.availability {
 		for i, node := range nodes {
 			if node == toRemove {