From c359a5117f9400a08b18f01daaaea13b09e3f235 Mon Sep 17 00:00:00 2001
From: chrislusf <chris.lu@gmail.com>
Date: Wed, 30 Mar 2016 12:34:11 -0700
Subject: [PATCH] add lock to dir children map

fix https://github.com/chrislusf/seaweedfs/issues/273
---
 go/filer/embedded_filer/directory_in_map.go | 60 +++++++++++++++------
 1 file changed, 44 insertions(+), 16 deletions(-)

diff --git a/go/filer/embedded_filer/directory_in_map.go b/go/filer/embedded_filer/directory_in_map.go
index a1679f93e..b142639ab 100644
--- a/go/filer/embedded_filer/directory_in_map.go
+++ b/go/filer/embedded_filer/directory_in_map.go
@@ -17,12 +17,43 @@ import (
 var writeLock sync.Mutex //serialize changes to dir.log
 
 type DirectoryEntryInMap struct {
+	sync.Mutex
 	Name           string
 	Parent         *DirectoryEntryInMap
-	SubDirectories map[string]*DirectoryEntryInMap
+	subDirectories map[string]*DirectoryEntryInMap
 	Id             filer.DirectoryId
 }
 
+func (de *DirectoryEntryInMap) getChild(dirName string) (*DirectoryEntryInMap, bool) {
+	de.Lock()
+	defer de.Unlock()
+	child, ok := de.subDirectories[dirName]
+	return child, ok
+}
+func (de *DirectoryEntryInMap) addChild(dirName string, child *DirectoryEntryInMap) {
+	de.Lock()
+	defer de.Unlock()
+	de.subDirectories[dirName] = child
+}
+func (de *DirectoryEntryInMap) removeChild(dirName string) {
+	de.Lock()
+	defer de.Unlock()
+	delete(de.subDirectories, dirName)
+}
+func (de *DirectoryEntryInMap) hasChildren() bool {
+	de.Lock()
+	defer de.Unlock()
+	return len(de.subDirectories) > 0
+}
+func (de *DirectoryEntryInMap) children() (dirNames []filer.DirectoryEntry) {
+	de.Lock()
+	defer de.Unlock()
+	for k, v := range de.subDirectories {
+		dirNames = append(dirNames, filer.DirectoryEntry{Name: k, Id: v.Id})
+	}
+	return dirNames
+}
+
 type DirectoryManagerInMap struct {
 	Root      *DirectoryEntryInMap
 	max       filer.DirectoryId
@@ -33,7 +64,7 @@ type DirectoryManagerInMap struct {
 func (dm *DirectoryManagerInMap) NewDirectoryEntryInMap(parent *DirectoryEntryInMap, name string) (d *DirectoryEntryInMap, err error) {
 	writeLock.Lock()
 	defer writeLock.Unlock()
-	d = &DirectoryEntryInMap{Name: name, Parent: parent, SubDirectories: make(map[string]*DirectoryEntryInMap)}
+	d = &DirectoryEntryInMap{Name: name, Parent: parent, subDirectories: make(map[string]*DirectoryEntryInMap)}
 	var parts []string
 	for p := d; p != nil && p.Name != ""; p = p.Parent {
 		parts = append(parts, p.Name)
@@ -60,7 +91,7 @@ func (dm *DirectoryManagerInMap) log(words ...string) {
 func NewDirectoryManagerInMap(dirLogFile string) (dm *DirectoryManagerInMap, err error) {
 	dm = &DirectoryManagerInMap{}
 	//dm.Root do not use NewDirectoryEntryInMap, since dm.max will be changed
-	dm.Root = &DirectoryEntryInMap{SubDirectories: make(map[string]*DirectoryEntryInMap)}
+	dm.Root = &DirectoryEntryInMap{subDirectories: make(map[string]*DirectoryEntryInMap)}
 	if dm.logFile, err = os.OpenFile(dirLogFile, os.O_RDWR|os.O_CREATE, 0644); err != nil {
 		return nil, fmt.Errorf("cannot write directory log file %s: %v", dirLogFile, err)
 	}
@@ -135,7 +166,7 @@ func (dm *DirectoryManagerInMap) findDirectory(dirPath string) (*DirectoryEntryI
 	parts := strings.Split(dirPath, "/")
 	dir := dm.Root
 	for i := 1; i < len(parts); i++ {
-		if sub, ok := dir.SubDirectories[parts[i]]; ok {
+		if sub, ok := dir.getChild(parts[i]); ok {
 			dir = sub
 		} else {
 			return dm.Root, fmt.Errorf("Directory %s Not Found", dirPath)
@@ -159,7 +190,7 @@ func (dm *DirectoryManagerInMap) loadDirectory(dirPath string, dirId filer.Direc
 	parts := strings.Split(dirPath, "/")
 	dir := dm.Root
 	for i := 1; i < len(parts); i++ {
-		sub, ok := dir.SubDirectories[parts[i]]
+		sub, ok := dir.getChild(parts[i])
 		if !ok {
 			if i != len(parts)-1 {
 				return fmt.Errorf("%s should be created after parent %s", dirPath, parts[i])
@@ -172,7 +203,7 @@ func (dm *DirectoryManagerInMap) loadDirectory(dirPath string, dirId filer.Direc
 			if sub.Id != dirId {
 				return fmt.Errorf("%s should be have id %v instead of %v", dirPath, sub.Id, dirId)
 			}
-			dir.SubDirectories[parts[i]] = sub
+			dir.addChild(parts[i], sub)
 		}
 		dir = sub
 	}
@@ -187,14 +218,14 @@ func (dm *DirectoryManagerInMap) makeDirectory(dirPath string) (dir *DirectoryEn
 	parts := strings.Split(dirPath, "/")
 	dir = dm.Root
 	for i := 1; i < len(parts); i++ {
-		sub, ok := dir.SubDirectories[parts[i]]
+		sub, ok := dir.getChild(parts[i])
 		if !ok {
 			var err error
 			sub, err = dm.NewDirectoryEntryInMap(dir, parts[i])
 			if err != nil {
 				return nil, false
 			}
-			dir.SubDirectories[parts[i]] = sub
+			dir.addChild(parts[i], sub)
 			created = true
 		}
 		dir = sub
@@ -219,11 +250,11 @@ func (dm *DirectoryManagerInMap) MoveUnderDirectory(oldDirPath string, newParent
 		return pe
 	}
 	dm.log("mov", oldDirPath, newParentDirPath, newName)
-	delete(oldDir.Parent.SubDirectories, oldDir.Name)
+	oldDir.Parent.removeChild(oldDir.Name)
 	if newName == "" {
 		newName = oldDir.Name
 	}
-	parentDir.SubDirectories[newName] = oldDir
+	parentDir.addChild(newName, oldDir)
 	oldDir.Name = newName
 	oldDir.Parent = parentDir
 	return nil
@@ -234,10 +265,7 @@ func (dm *DirectoryManagerInMap) ListDirectories(dirPath string) (dirNames []fil
 	if e != nil {
 		return dirNames, e
 	}
-	for k, v := range d.SubDirectories {
-		dirNames = append(dirNames, filer.DirectoryEntry{Name: k, Id: v.Id})
-	}
-	return dirNames, nil
+	return d.children(), nil
 }
 func (dm *DirectoryManagerInMap) DeleteDirectory(dirPath string) error {
 	writeLock.Lock()
@@ -249,10 +277,10 @@ func (dm *DirectoryManagerInMap) DeleteDirectory(dirPath string) error {
 	if e != nil {
 		return e
 	}
-	if len(d.SubDirectories) != 0 {
+	if d.hasChildren() {
 		return fmt.Errorf("dir %s still has sub directories", dirPath)
 	}
-	delete(d.Parent.SubDirectories, d.Name)
+	d.Parent.removeChild(d.Name)
 	d.Parent = nil
 	dm.log("del", dirPath)
 	return nil