diff --git a/cmd/olliesrv/server.go b/cmd/olliesrv/server.go
index 203d835..3f99889 100644
--- a/cmd/olliesrv/server.go
+++ b/cmd/olliesrv/server.go
@@ -562,7 +562,9 @@ func read(root *fs.Tree, cs *connState, fc *plan9.Fcall, ctx context.Context) *p
 		f, fidOK := cs.fids[fc.Fid]
 		var base string
 		if fidOK {
+			f.mu.Lock()
 			base = f.waitBase
+			f.mu.Unlock()
 		}
 		cs.mu.RUnlock()
 		waitCtx, waitCancel := context.WithTimeout(ctx, 5*time.Second)
@@ -595,7 +597,9 @@ func read(root *fs.Tree, cs *connState, fc *plan9.Fcall, ctx context.Context) *p
 		f, fidOK := cs.fids[fc.Fid]
 		var base string
 		if fidOK {
+			f.mu.Lock()
 			base = f.waitBase
+			f.mu.Unlock()
 		}
 		cs.mu.RUnlock()
 		waitCtx, waitCancel := context.WithCancel(ctx)
@@ -683,24 +687,28 @@ func write(cs *connState, fc *plan9.Fcall) *plan9.Fcall {
 		cs.mu.Unlock()
 		return errFcall(fc, "bad fid")
 	}
-
-	if f.entry != nil && f.entry.RdwrMode() {
-		f.readCache = nil // clear cached response for next read
-		cs.mu.Unlock()
-		if err := f.entry.Write(fc.Data); err != nil {
-			return errFcall(fc, err.Error())
+	f.mu.Lock()
+	entry := f.entry
+	if entry != nil && entry.RdwrMode() {
+		f.readCache = nil
+	}
+	if entry == nil || !entry.RdwrMode() {
+		end := int(fc.Offset) + len(fc.Data)
+		if end > len(f.writeBuf) {
+			grown := make([]byte, end)
+			copy(grown, f.writeBuf)
+			f.writeBuf = grown
 		}
+		copy(f.writeBuf[fc.Offset:], fc.Data)
+		f.mu.Unlock()
+		cs.mu.Unlock()
 		return &plan9.Fcall{Type: plan9.Rwrite, Tag: fc.Tag, Count: uint32(len(fc.Data))}
 	}
-
-	end := int(fc.Offset) + len(fc.Data)
-	if end > len(f.writeBuf) {
-		grown := make([]byte, end)
-		copy(grown, f.writeBuf)
-		f.writeBuf = grown
-	}
-	copy(f.writeBuf[fc.Offset:], fc.Data)
+	f.mu.Unlock()
 	cs.mu.Unlock()
+	if err := entry.Write(fc.Data); err != nil {
+		return errFcall(fc, err.Error())
+	}
 	return &plan9.Fcall{Type: plan9.Rwrite, Tag: fc.Tag, Count: uint32(len(fc.Data))}
 }
 
@@ -711,13 +719,16 @@ func stat(root *fs.Tree, cs *connState, fc *plan9.Fcall) *plan9.Fcall {
 	if !ok {
 		return errFcall(fc, "bad fid")
 	}
-	if _, err := root.Stat(f.path[1:]); err != nil {
+	f.mu.Lock()
+	path := f.path
+	f.mu.Unlock()
+	if _, err := root.Stat(path[1:]); err != nil {
 		cs.mu.Lock()
 		delete(cs.fids, fc.Fid)
 		cs.mu.Unlock()
 		return errFcall(fc, "file not found")
 	}
-	dir := makeStat(root, f.path)
+	dir := makeStat(root, path)
 	stat, err := dir.Bytes()
 	if err != nil {
 		return errFcall(fc, err.Error())
@@ -736,22 +747,29 @@ func wstat(root *fs.Tree, cs *connState, fc *plan9.Fcall) *plan9.Fcall {
 	if err != nil {
 		return &plan9.Fcall{Type: plan9.Rwstat, Tag: fc.Tag}
 	}
-	oldName := pathBase(f.path)
+	f.mu.Lock()
+	path := f.path
+	f.mu.Unlock()
+	oldName := pathBase(path)
 	if newDir.Name == "" || newDir.Name == oldName {
 		return &plan9.Fcall{Type: plan9.Rwstat, Tag: fc.Tag}
 	}
-	if err := root.Rename(f.path[1:], newDir.Name); err != nil {
+	if err := root.Rename(path[1:], newDir.Name); err != nil {
 		return errFcall(fc, err.Error())
 	}
 	// GC stale fids on this connection referencing the old path
-	oldPrefix := f.path
+	oldPrefix := path
 	var stale []fs.File
 	cs.mu.Lock()
 	for id, fid := range cs.fids {
-		if fid.path == oldPrefix || strings.HasPrefix(fid.path, oldPrefix+"/") {
+		fid.mu.Lock()
+		fidPath := fid.path
+		entry := fid.entry
+		fid.mu.Unlock()
+		if fidPath == oldPrefix || strings.HasPrefix(fidPath, oldPrefix+"/") {
 			delete(cs.fids, id)
-			if fid.entry != nil {
-				stale = append(stale, fid.entry)
+			if entry != nil {
+				stale = append(stale, entry)
 			}
 		}
 	}
@@ -770,20 +788,28 @@ func clunk(root *fs.Tree, cs *connState, fc *plan9.Fcall) *plan9.Fcall {
 	var writable bool
 	var isRequest bool
 	if ok {
-		if m := f.mode & 3; m == plan9.OWRITE || m == plan9.ORDWR {
-			path = f.path
+		f.mu.Lock()
+		mode := f.mode
+		path = f.path
+		data = append([]byte(nil), f.writeBuf...)
+		entry := f.entry
+		if mode&3 == plan9.OWRITE || mode&3 == plan9.ORDWR {
 			writable = true
-			data = make([]byte, len(f.writeBuf))
-			copy(data, f.writeBuf)
-			if f.entry != nil {
-				isRequest = f.entry.RdwrMode()
+			if entry != nil {
+				isRequest = entry.RdwrMode()
 			}
 		}
+		f.mu.Unlock()
 		delete(cs.fids, fc.Fid)
 	}
 	cs.mu.Unlock()
-	if f != nil && f.entry != nil {
-		_ = f.entry.Close()
+	if f != nil {
+		f.mu.Lock()
+		entry := f.entry
+		f.mu.Unlock()
+		if entry != nil {
+			_ = entry.Close()
+		}
 	}
 	if writable && !isRequest {
 		input := strings.TrimSpace(string(data))
@@ -805,16 +831,21 @@ func remove(root *fs.Tree, cs *connState, fc *plan9.Fcall) *plan9.Fcall {
 		delete(cs.fids, fc.Fid)
 	}
 	cs.mu.Unlock()
-	if ok && f.entry != nil {
-		_ = f.entry.Close()
+	var entry fs.File
+	if ok {
+		f.mu.Lock()
+		entry = f.entry
+		path := f.path
+		f.mu.Unlock()
+		if entry != nil {
+			_ = entry.Close()
+		}
+		if err := root.Delete(path[1:]); err != nil {
+			return errFcall(fc, err.Error())
+		}
+		return &plan9.Fcall{Type: plan9.Rremove, Tag: fc.Tag}
 	}
-	if !ok {
-		return errFcall(fc, "bad fid")
-	}
-	if err := root.Delete(f.path[1:]); err != nil {
-		return errFcall(fc, err.Error())
-	}
-	return &plan9.Fcall{Type: plan9.Rremove, Tag: fc.Tag}
+	return errFcall(fc, "bad fid")
 }
 
 func (s *Server) Kill() {