From 6c476f4fb8310749d8aa98ef6ac910ebe83fc3e5 Mon Sep 17 00:00:00 2001
From: Ollie Agent <ollie@example.com>
Date: Tue, 18 Aug 2026 07:41:59 +0200
Subject: [PATCH] Synchronize toolsrv fid state

---
 cmd/toolsrv/p9.go | 42 ++++++++++++++++++++++++++++++------------
 1 file changed, 30 insertions(+), 12 deletions(-)

diff --git a/cmd/toolsrv/p9.go b/cmd/toolsrv/p9.go
index 78cb8ba..cb099b7 100644
--- a/cmd/toolsrv/p9.go
+++ b/cmd/toolsrv/p9.go
@@ -17,6 +17,7 @@ import (
 
 // fid represents an open file handle.
 type fid struct {
+	mu       sync.Mutex
 	path     string
 	qid      plan9.Qid
 	mode     uint8
@@ -393,20 +394,28 @@ func handleRead(cs *connState, fc *plan9.Fcall, tree *virtfs.Tree) *plan9.Fcall
 	if !isFid {
 		return errFcall(fc, "unknown fid")
 	}
-	if !f.opened {
+	f.mu.Lock()
+	opened := f.opened
+	qid := f.qid
+	entry := f.entry
+	f.mu.Unlock()
+	if !opened {
 		return errFcall(fc, "not open")
 	}
 
-	if f.qid.Type&plan9.QTDIR != 0 {
+	if qid.Type&plan9.QTDIR != 0 {
 		return handleDirRead(cs, f, fc, tree)
 	}
 
-	if f.entry == nil {
+	if entry == nil {
 		return errFcall(fc, "no entry")
 	}
 
 	// For rdwr files, check if we've already read
-	if f.entry.RdwrMode() && f.readDone {
+	f.mu.Lock()
+	readDone := entry.RdwrMode() && f.readDone
+	f.mu.Unlock()
+	if readDone {
 		return &plan9.Fcall{Type: plan9.Rread, Tag: fc.Tag, Data: nil}
 	}
 
@@ -494,8 +503,12 @@ func readSlice(fc *plan9.Fcall, content []byte) *plan9.Fcall {
 }
 
 func handleDirRead(cs *connState, f *fid, fc *plan9.Fcall, tree *virtfs.Tree) *plan9.Fcall {
-	if fc.Offset == 0 || f.dirCache == nil {
-		path := f.path
+	f.mu.Lock()
+	path := f.path
+	qidPath := f.path
+	cached := f.dirCache
+	f.mu.Unlock()
+	if fc.Offset == 0 || cached == nil {
 		if path == "/" {
 			path = ""
 		} else {
@@ -517,7 +530,7 @@ func handleDirRead(cs *connState, f *fid, fc *plan9.Fcall, tree *virtfs.Tree) *p
 			}
 			dir := plan9.Dir{
 				Name: e.Name(),
-				Qid:  plan9.Qid{Type: qt, Path: pathHash(f.path + "/" + e.Name())},
+				Qid:  plan9.Qid{Type: qt, Path: pathHash(qidPath + "/" + e.Name())},
 				Mode: mode,
 				Uid:  "toolsrv",
 				Gid:  "toolsrv",
@@ -525,20 +538,25 @@ func handleDirRead(cs *connState, f *fid, fc *plan9.Fcall, tree *virtfs.Tree) *p
 			data, _ := dir.Bytes()
 			buf = append(buf, data...)
 		}
-		f.dirCache = buf
+		f.mu.Lock()
+		if fc.Offset == 0 || f.dirCache == nil {
+			f.dirCache = buf
+		}
+		cached = f.dirCache
+		f.mu.Unlock()
 	}
 
 	offset := int(fc.Offset)
-	if offset >= len(f.dirCache) {
+	if offset >= len(cached) {
 		return &plan9.Fcall{Type: plan9.Rread, Tag: fc.Tag, Data: nil}
 	}
 
 	end := offset + int(fc.Count)
-	if end > len(f.dirCache) {
-		end = len(f.dirCache)
+	if end > len(cached) {
+		end = len(cached)
 	}
 
-	return &plan9.Fcall{Type: plan9.Rread, Tag: fc.Tag, Data: f.dirCache[offset:end]}
+	return &plan9.Fcall{Type: plan9.Rread, Tag: fc.Tag, Data: cached[offset:end]}
 }
 
 func handleWrite(cs *connState, fc *plan9.Fcall, tree *virtfs.Tree) *plan9.Fcall {