From 8c1b7f6c86103d3d66d236b8c8e1ca5ceee602e2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rn=20Friedrich=20Dreyer?= <jfd@butonic.de>
Date: Tue, 3 Dec 2024 10:43:37 +0100
Subject: [PATCH] drop unneeded session locks
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Jörn Friedrich Dreyer <jfd@butonic.de>
---
 changelog/unreleased/drop-unneeded-locks.md      |  5 +++++
 pkg/storage/utils/decomposedfs/upload/session.go | 14 --------------
 pkg/storage/utils/decomposedfs/upload/store.go   | 14 +++++---------
 3 files changed, 10 insertions(+), 23 deletions(-)
 create mode 100644 changelog/unreleased/drop-unneeded-locks.md

diff --git a/changelog/unreleased/drop-unneeded-locks.md b/changelog/unreleased/drop-unneeded-locks.md
new file mode 100644
index 0000000000..166f6c31b0
--- /dev/null
+++ b/changelog/unreleased/drop-unneeded-locks.md
@@ -0,0 +1,5 @@
+Bugfix: drop unneeded session locks
+
+We no longer lock session metadada files, as they are already written atomically.
+
+https://github.com/cs3org/reva/pull/4985
diff --git a/pkg/storage/utils/decomposedfs/upload/session.go b/pkg/storage/utils/decomposedfs/upload/session.go
index bbcad25329..b69f9999f5 100644
--- a/pkg/storage/utils/decomposedfs/upload/session.go
+++ b/pkg/storage/utils/decomposedfs/upload/session.go
@@ -27,7 +27,6 @@ import (
 	"time"
 
 	"github.com/google/renameio/v2"
-	"github.com/rogpeppe/go-internal/lockedfile"
 	tusd "github.com/tus/tusd/v2/pkg/handler"
 
 	userpb "github.com/cs3org/go-cs3apis/cs3/identity/user/v1beta1"
@@ -84,14 +83,6 @@ func (s *OcisSession) Purge(ctx context.Context) error {
 	_, span := tracer.Start(ctx, "Purge")
 	defer span.End()
 	sessionPath := sessionPath(s.store.root, s.info.ID)
-	f, err := lockedfile.OpenFile(sessionPath+".lock", os.O_RDWR|os.O_TRUNC|os.O_CREATE, 0600)
-	if err != nil {
-		return err
-	}
-	defer func() {
-		f.Close()
-		os.Remove(sessionPath + ".lock")
-	}()
 	if err := os.Remove(sessionPath); err != nil {
 		return err
 	}
@@ -127,11 +118,6 @@ func (s *OcisSession) Persist(ctx context.Context) error {
 	if err != nil {
 		return err
 	}
-	f, err := lockedfile.OpenFile(sessionPath+".lock", os.O_RDWR|os.O_TRUNC|os.O_CREATE, 0600)
-	if err != nil {
-		return err
-	}
-	defer f.Close()
 	return renameio.WriteFile(sessionPath, d, 0600)
 }
 
diff --git a/pkg/storage/utils/decomposedfs/upload/store.go b/pkg/storage/utils/decomposedfs/upload/store.go
index df1e4df7a5..52049061c6 100644
--- a/pkg/storage/utils/decomposedfs/upload/store.go
+++ b/pkg/storage/utils/decomposedfs/upload/store.go
@@ -28,6 +28,7 @@ import (
 	"regexp"
 	"strconv"
 	"strings"
+	"syscall"
 	"time"
 
 	provider "github.com/cs3org/go-cs3apis/cs3/storage/provider/v1beta1"
@@ -129,24 +130,19 @@ func (store OcisStore) Get(ctx context.Context, id string) (*OcisSession, error)
 		store: store,
 		info:  tusd.FileInfo{},
 	}
-	lock, err := lockedfile.Open(sessionPath + ".lock")
+	data, err := os.ReadFile(sessionPath)
 	if err != nil {
-		if errors.Is(err, iofs.ErrNotExist) {
-			// Interpret os.ErrNotExist as 404 Not Found
+		// handle stale NFS file handles that can occur when the file is deleted betwenn the ATTR and FOPEN call of os.ReadFile
+		if pathErr, ok := err.(*os.PathError); ok && pathErr.Err == syscall.ESTALE {
+			appctx.GetLogger(ctx).Info().Str("session", id).Err(err).Msg("treating stale file handle as not found")
 			err = tusd.ErrNotFound
 		}
-		return nil, err
-	}
-	defer lock.Close()
-	data, err := os.ReadFile(sessionPath)
-	if err != nil {
 		if errors.Is(err, iofs.ErrNotExist) {
 			// Interpret os.ErrNotExist as 404 Not Found
 			err = tusd.ErrNotFound
 		}
 		return nil, err
 	}
-	lock.Close() // release lock asap
 
 	if err := json.Unmarshal(data, &session.info); err != nil {
 		return nil, err