Implement Sync() to directories

Updates #1035, #1199

PiperOrigin-RevId: 317028108

2 files changed, 6 insertions, 5 deletions

diff --git a/pkg/sentry/fsimpl/tmpfs/regular_file.go b/pkg/sentry/fsimpl/tmpfs/regular_file.go
index 77447b32c..bfd9c5995 100644
--- a/pkg/sentry/fsimpl/tmpfs/regular_file.go
+++ b/pkg/sentry/fsimpl/tmpfs/regular_file.go
@@ -360,11 +360,6 @@ func (fd *regularFileFD) Seek(ctx context.Context, offset int64, whence int32) (
 	return offset, nil
 }
 
-// Sync implements vfs.FileDescriptionImpl.Sync.
-func (fd *regularFileFD) Sync(ctx context.Context) error {
-	return nil
-}
-
 // ConfigureMMap implements vfs.FileDescriptionImpl.ConfigureMMap.
 func (fd *regularFileFD) ConfigureMMap(ctx context.Context, opts *memmap.MMapOpts) error {
 	file := fd.inode().impl.(*regularFile)
diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs.go b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
index d0a3e1a5c..a94333ee0 100644
--- a/pkg/sentry/fsimpl/tmpfs/tmpfs.go
+++ b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
@@ -778,3 +778,9 @@ func (fd *fileDescription) LockPOSIX(ctx context.Context, uid fslock.UniqueID, t
 func (fd *fileDescription) UnlockPOSIX(ctx context.Context, uid fslock.UniqueID, start, length uint64, whence int16) error {
 	return fd.Locks().UnlockPOSIX(ctx, &fd.vfsfd, uid, start, length, whence)
 }
+
+// Sync implements vfs.FileDescriptionImpl.Sync. It does nothing because all
+// filesystem state is in-memory.
+func (*fileDescription) Sync(context.Context) error {
+	return nil
+}