From b524a40375d322900e65ba60cc924efe761c660b Mon Sep 17 00:00:00 2001
From: Chris Lu <chris.lu@gmail.com>
Date: Wed, 8 Apr 2020 12:50:34 -0700
Subject: [PATCH] add locking to fs cache

---
 weed/filesys/fscache.go | 33 +++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

diff --git a/weed/filesys/fscache.go b/weed/filesys/fscache.go
index ca8c7de5b..831f3808c 100644
--- a/weed/filesys/fscache.go
+++ b/weed/filesys/fscache.go
@@ -9,6 +9,7 @@ import (
 
 type FsCache struct {
 	root *FsNode
+	sync.RWMutex
 }
 type FsNode struct {
 	parent       *FsNode
@@ -27,6 +28,14 @@ func newFsCache(root fs.Node) *FsCache {
 }
 
 func (c *FsCache) GetFsNode(path util.FullPath) fs.Node {
+
+	c.RLock()
+	defer c.RUnlock()
+
+	return c.doGetFsNode(path)
+}
+
+func (c *FsCache) doGetFsNode(path util.FullPath) fs.Node {
 	t := c.root
 	for _, p := range path.Split() {
 		t = t.findChild(p)
@@ -38,6 +47,14 @@ func (c *FsCache) GetFsNode(path util.FullPath) fs.Node {
 }
 
 func (c *FsCache) SetFsNode(path util.FullPath, node fs.Node) {
+
+	c.Lock()
+	defer c.Unlock()
+
+	c.doSetFsNode(path, node)
+}
+
+func (c *FsCache) doSetFsNode(path util.FullPath, node fs.Node) {
 	t := c.root
 	for _, p := range path.Split() {
 		t = t.ensureChild(p)
@@ -45,17 +62,26 @@ func (c *FsCache) SetFsNode(path util.FullPath, node fs.Node) {
 	t.node = node
 }
 
+
 func (c *FsCache) EnsureFsNode(path util.FullPath, genNodeFn func() fs.Node) fs.Node {
-	t := c.GetFsNode(path)
+
+	c.Lock()
+	defer c.Unlock()
+
+	t := c.doGetFsNode(path)
 	if t != nil {
 		return t
 	}
 	t = genNodeFn()
-	c.SetFsNode(path, t)
+	c.doSetFsNode(path, t)
 	return t
 }
 
 func (c *FsCache) DeleteFsNode(path util.FullPath) {
+
+	c.Lock()
+	defer c.Unlock()
+
 	t := c.root
 	for _, p := range path.Split() {
 		t = t.findChild(p)
@@ -72,6 +98,9 @@ func (c *FsCache) DeleteFsNode(path util.FullPath) {
 // oldPath and newPath are full path including the new name
 func (c *FsCache) Move(oldPath util.FullPath, newPath util.FullPath) *FsNode {
 
+	c.Lock()
+	defer c.Unlock()
+
 	// find old node
 	src := c.root
 	for _, p := range oldPath.Split() {