Implement sync_test.go + workload scenarios for fsync, fdatasync, sync, sync_file_range

- Add syncFdatasync, syncSync, syncSyncFileRange scenario functions
- Register sync-fdatasync, sync-sync, sync-sync-file-range in scenarios map
- Add sync_test.go with tests for all 4 sync-related syscalls
- sync is a null_event (no path); others are fd_events
- All use direct SYS_* syscalls on amd64 (no wrapper delegation)

Task: #343
Amp-Thread-ID: https://ampcode.com/threads/T-019c813f-e020-7558-86ce-be6fdbd96f98
Co-authored-by: Amp <amp@ampcode.com>

2 files changed, 101 insertions, 2 deletions

diff --git a/integrationtests/cmd/ioworkload/scenarios.go b/integrationtests/cmd/ioworkload/scenarios.go
index bf1561c..e87d53e 100644
--- a/integrationtests/cmd/ioworkload/scenarios.go
+++ b/integrationtests/cmd/ioworkload/scenarios.go
@@ -48,8 +48,11 @@ var scenarios = map[string]func() error{
 	"stat-statx":      statStatx,
 	"stat-access":     statAccess,
 	"stat-faccessat":  statFaccessat,
-	"sync-basic":      syncBasic,
-	"truncate-basic":  truncateBasic,
+	"sync-basic":            syncBasic,
+	"sync-fdatasync":        syncFdatasync,
+	"sync-sync":             syncSync,
+	"sync-sync-file-range":  syncSyncFileRange,
+	"truncate-basic":        truncateBasic,
 }
 
 func makeTempDir(prefix string) (string, func(), error) {
@@ -1285,6 +1288,56 @@ func syncBasic() error {
 	return syscall.Fsync(fd)
 }
 
+// syncFdatasync opens a file, writes data, and fdatasyncs it.
+func syncFdatasync() error {
+	dir, cleanup, err := makeTempDir("sync-fdatasync")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	path := filepath.Join(dir, "fdatasyncfile.txt")
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	defer syscall.Close(fd)
+
+	if _, err := syscall.Write(fd, []byte("fdatasync me")); err != nil {
+		return fmt.Errorf("write: %w", err)
+	}
+	return syscall.Fdatasync(fd)
+}
+
+// syncSync calls sync(2) to flush all filesystem caches.
+// sync is a null_event with no file arguments.
+func syncSync() error {
+	syscall.Sync()
+	return nil
+}
+
+// syncSyncFileRange opens a file, writes data, then calls sync_file_range(2).
+func syncSyncFileRange() error {
+	dir, cleanup, err := makeTempDir("sync-sync-file-range")
+	if err != nil {
+		return err
+	}
+	defer cleanup()
+
+	path := filepath.Join(dir, "syncrangefile.txt")
+	fd, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	if err != nil {
+		return fmt.Errorf("open: %w", err)
+	}
+	defer syscall.Close(fd)
+
+	data := []byte("sync file range data")
+	if _, err := syscall.Write(fd, data); err != nil {
+		return fmt.Errorf("write: %w", err)
+	}
+	return syscall.SyncFileRange(fd, 0, int64(len(data)), 0)
+}
+
 // truncateBasic opens a file, writes data, and truncates it.
 func truncateBasic() error {
 	dir, cleanup, err := makeTempDir("truncate-basic")
diff --git a/integrationtests/sync_test.go b/integrationtests/sync_test.go
new file mode 100644
index 0000000..5f6a314
--- /dev/null
+++ b/integrationtests/sync_test.go
@@ -0,0 +1,46 @@
+package integrationtests
+
+import "testing"
+
+func TestSyncBasic(t *testing.T) {
+	runScenario(t, "sync-basic", []ExpectedEvent{
+		{
+			PathContains: "syncfile.txt",
+			Tracepoint:   "enter_fsync",
+			Comm:         "ioworkload",
+			MinCount:     1,
+		},
+	})
+}
+
+func TestSyncFdatasync(t *testing.T) {
+	runScenario(t, "sync-fdatasync", []ExpectedEvent{
+		{
+			PathContains: "fdatasyncfile.txt",
+			Tracepoint:   "enter_fdatasync",
+			Comm:         "ioworkload",
+			MinCount:     1,
+		},
+	})
+}
+
+func TestSyncSync(t *testing.T) {
+	runScenario(t, "sync-sync", []ExpectedEvent{
+		{
+			Tracepoint: "enter_sync",
+			Comm:       "ioworkload",
+			MinCount:   1,
+		},
+	})
+}
+
+func TestSyncSyncFileRange(t *testing.T) {
+	runScenario(t, "sync-sync-file-range", []ExpectedEvent{
+		{
+			PathContains: "syncrangefile.txt",
+			Tracepoint:   "enter_sync_file_range",
+			Comm:         "ioworkload",
+			MinCount:     1,
+		},
+	})
+}