fsimpl/gofer: implement specialFileFD.InvalidateUnsavable()

nixprime · gvisor-bot · commit 64e48cc3c69b · 2024-11-26T14:46:38.000-08:00
This fixes save/restore of mmapped gofer.specialFileFDs (usually obtained via
mount option "disable_file_handle_sharing") for which mappings have actually
been used (mm.pmas have been obtained).

PiperOrigin-RevId: 700465816
diff --git a/pkg/sentry/fsimpl/gofer/special_file.go b/pkg/sentry/fsimpl/gofer/special_file.go
@@ -482,6 +482,10 @@ func (fd *specialFileFD) Translate(ctx context.Context, required, optional memma
 
 // InvalidateUnsavable implements memmap.Mappable.InvalidateUnsavable.
 func (fd *specialFileFD) InvalidateUnsavable(ctx context.Context) error {
+	d := fd.dentry()
+	d.mapsMu.Lock()
+	defer d.mapsMu.Unlock()
+	d.mappings.InvalidateAll(memmap.InvalidateOpts{})
 	return nil
 }
 

Original file line number	Diff line number	Diff line change
`@@ -482,6 +482,10 @@ func (fd *specialFileFD) Translate(ctx context.Context, required, optional memma`
`482`	`482`
`483`	`483`	`// InvalidateUnsavable implements memmap.Mappable.InvalidateUnsavable.`
`484`	`484`	`func (fd *specialFileFD) InvalidateUnsavable(ctx context.Context) error {`
	`485`	`+ d := fd.dentry()`
	`486`	`+ d.mapsMu.Lock()`
	`487`	`+ defer d.mapsMu.Unlock()`
	`488`	`+ d.mappings.InvalidateAll(memmap.InvalidateOpts{})`
`485`	`489`	`return nil`
`486`	`490`	`}`
`487`	`491`