From 0bfa03d61c7791aad03da5ac021bc60e4578858e Mon Sep 17 00:00:00 2001
From: Zhaozhong Ni <nzz@google.com>
Date: Thu, 11 Oct 2018 11:40:34 -0700
Subject: sentry: allow saving of unlinked files with open fds on virtual fs.
PiperOrigin-RevId: 216733414
Change-Id: I33cd3eb818f0c39717d6656fcdfff6050b37ebb0
---
pkg/sentry/fs/dirent_state.go | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
(limited to 'pkg/sentry/fs')
diff --git a/pkg/sentry/fs/dirent_state.go b/pkg/sentry/fs/dirent_state.go
index 58dd01202..04ab197b9 100644
--- a/pkg/sentry/fs/dirent_state.go
+++ b/pkg/sentry/fs/dirent_state.go
@@ -23,16 +23,20 @@ import (
// beforeSave is invoked by stateify.
func (d *Dirent) beforeSave() {
- // Refuse to save if the file has already been deleted (but still has
- // open fds, which is why the Dirent is still accessible). We know the
- // the restore opening of the file will always fail. This condition will
- // last until all the open fds and this Dirent are closed and released.
+ // Refuse to save if the file is on a non-virtual file system and has
+ // already been deleted (but still has open fds, which is why the Dirent
+ // is still accessible). We know the the restore re-opening of the file
+ // will always fail. This condition will last until all the open fds and
+ // this Dirent are closed and released.
+ //
+ // Such "dangling" open files on virtual file systems (e.g., tmpfs) is
+ // OK to save as their restore does not require re-opening the files.
//
// Note that this is rejection rather than failure---it would be
// perfectly OK to save---we are simply disallowing it here to prevent
// generating non-restorable state dumps. As the program continues its
// execution, it may become allowed to save again.
- if atomic.LoadInt32(&d.deleted) != 0 {
+ if !d.Inode.IsVirtual() && atomic.LoadInt32(&d.deleted) != 0 {
n, _ := d.FullName(nil /* root */)
panic(ErrSaveRejection{fmt.Errorf("deleted file %q still has open fds", n)})
}
--
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