5 files changed, 54 insertions, 28 deletions
diff --git a/pkg/sentry/fsimpl/tmpfs/fstree.go b/pkg/sentry/fsimpl/tmpfs/fstree.go
index 2dd98a921..d46351488 100644
--- a/pkg/sentry/fsimpl/tmpfs/fstree.go
+++ b/pkg/sentry/fsimpl/tmpfs/fstree.go
@@ -34,7 +34,7 @@ func genericPrependPath(vfsroot vfs.VirtualDentry, mnt *vfs.Mount, d *dentry, b
 		if mnt == vfsroot.Mount() && &d.vfsd == vfsroot.Dentry() {
 			return vfs.PrependPathAtVFSRootError{}
 		}
-		if &d.vfsd == mnt.Root() {
+		if mnt != nil && &d.vfsd == mnt.Root() {
 			return nil
 		}
 		if d.parent == nil {
@@ -44,3 +44,12 @@ func genericPrependPath(vfsroot vfs.VirtualDentry, mnt *vfs.Mount, d *dentry, b
 		d = d.parent
 	}
 }
+
+// DebugPathname returns a pathname to d relative to its filesystem root.
+// DebugPathname does not correspond to any Linux function; it's used to
+// generate dentry pathnames for debugging.
+func genericDebugPathname(d *dentry) string {
+	var b fspath.Builder
+	_ = genericPrependPath(vfs.VirtualDentry{}, nil, d, &b)
+	return b.String()
+}
diff --git a/pkg/sentry/fsimpl/tmpfs/regular_file.go b/pkg/sentry/fsimpl/tmpfs/regular_file.go
index ce4e3eda7..98680fde9 100644
--- a/pkg/sentry/fsimpl/tmpfs/regular_file.go
+++ b/pkg/sentry/fsimpl/tmpfs/regular_file.go
@@ -42,7 +42,7 @@ type regularFile struct {
 	inode inode
 
 	// memFile is a platform.File used to allocate pages to this regularFile.
-	memFile *pgalloc.MemoryFile
+	memFile *pgalloc.MemoryFile `state:"nosave"`
 
 	// memoryUsageKind is the memory accounting category under which pages backing
 	// this regularFile's contents are accounted.
@@ -92,7 +92,7 @@ type regularFile struct {
 
 func (fs *filesystem) newRegularFile(kuid auth.KUID, kgid auth.KGID, mode linux.FileMode) *inode {
 	file := &regularFile{
-		memFile:         fs.memFile,
+		memFile:         fs.mfp.MemoryFile(),
 		memoryUsageKind: usage.Tmpfs,
 		seals:           linux.F_SEAL_SEAL,
 	}
diff --git a/pkg/sentry/fsimpl/tmpfs/save_restore.go b/pkg/sentry/fsimpl/tmpfs/save_restore.go
new file mode 100644
index 000000000..b27f75cc2
--- /dev/null
+++ b/pkg/sentry/fsimpl/tmpfs/save_restore.go
@@ -0,0 +1,20 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package tmpfs
+
+// afterLoad is called by stateify.
+func (rf *regularFile) afterLoad() {
+	rf.memFile = rf.inode.fs.mfp.MemoryFile()
+}
diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs.go b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
index e2a0aac69..4ce859d57 100644
--- a/pkg/sentry/fsimpl/tmpfs/tmpfs.go
+++ b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
@@ -61,8 +61,9 @@ type FilesystemType struct{}
 type filesystem struct {
 	vfsfs vfs.Filesystem
 
-	// memFile is used to allocate pages to for regular files.
-	memFile *pgalloc.MemoryFile
+	// mfp is used to allocate memory that stores regular file contents. mfp is
+	// immutable.
+	mfp pgalloc.MemoryFileProvider
 
 	// clock is a realtime clock used to set timestamps in file operations.
 	clock time.Clock
@@ -106,8 +107,8 @@ type FilesystemOpts struct {
 
 // GetFilesystem implements vfs.FilesystemType.GetFilesystem.
 func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.VirtualFilesystem, creds *auth.Credentials, _ string, opts vfs.GetFilesystemOptions) (*vfs.Filesystem, *vfs.Dentry, error) {
-	memFileProvider := pgalloc.MemoryFileProviderFromContext(ctx)
-	if memFileProvider == nil {
+	mfp := pgalloc.MemoryFileProviderFromContext(ctx)
+	if mfp == nil {
 		panic("MemoryFileProviderFromContext returned nil")
 	}
 
@@ -181,7 +182,7 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
 	}
 	clock := time.RealtimeClockFromContext(ctx)
 	fs := filesystem{
-		memFile:  memFileProvider.MemoryFile(),
+		mfp:      mfp,
 		clock:    clock,
 		devMinor: devMinor,
 	}
diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs_state_autogen.go b/pkg/sentry/fsimpl/tmpfs/tmpfs_state_autogen.go
index 21681ba5c..21c53afaf 100644
--- a/pkg/sentry/fsimpl/tmpfs/tmpfs_state_autogen.go
+++ b/pkg/sentry/fsimpl/tmpfs/tmpfs_state_autogen.go
@@ -212,7 +212,6 @@ func (rf *regularFile) StateTypeName() string {
 func (rf *regularFile) StateFields() []string {
 	return []string{
 		"inode",
-		"memFile",
 		"memoryUsageKind",
 		"mappings",
 		"writableMappingPages",
@@ -227,26 +226,23 @@ func (rf *regularFile) beforeSave() {}
 func (rf *regularFile) StateSave(stateSinkObject state.Sink) {
 	rf.beforeSave()
 	stateSinkObject.Save(0, &rf.inode)
-	stateSinkObject.Save(1, &rf.memFile)
-	stateSinkObject.Save(2, &rf.memoryUsageKind)
-	stateSinkObject.Save(3, &rf.mappings)
-	stateSinkObject.Save(4, &rf.writableMappingPages)
-	stateSinkObject.Save(5, &rf.data)
-	stateSinkObject.Save(6, &rf.seals)
-	stateSinkObject.Save(7, &rf.size)
+	stateSinkObject.Save(1, &rf.memoryUsageKind)
+	stateSinkObject.Save(2, &rf.mappings)
+	stateSinkObject.Save(3, &rf.writableMappingPages)
+	stateSinkObject.Save(4, &rf.data)
+	stateSinkObject.Save(5, &rf.seals)
+	stateSinkObject.Save(6, &rf.size)
 }
 
-func (rf *regularFile) afterLoad() {}
-
 func (rf *regularFile) StateLoad(stateSourceObject state.Source) {
 	stateSourceObject.Load(0, &rf.inode)
-	stateSourceObject.Load(1, &rf.memFile)
-	stateSourceObject.Load(2, &rf.memoryUsageKind)
-	stateSourceObject.Load(3, &rf.mappings)
-	stateSourceObject.Load(4, &rf.writableMappingPages)
-	stateSourceObject.Load(5, &rf.data)
-	stateSourceObject.Load(6, &rf.seals)
-	stateSourceObject.Load(7, &rf.size)
+	stateSourceObject.Load(1, &rf.memoryUsageKind)
+	stateSourceObject.Load(2, &rf.mappings)
+	stateSourceObject.Load(3, &rf.writableMappingPages)
+	stateSourceObject.Load(4, &rf.data)
+	stateSourceObject.Load(5, &rf.seals)
+	stateSourceObject.Load(6, &rf.size)
+	stateSourceObject.AfterLoad(rf.afterLoad)
 }
 
 func (fd *regularFileFD) StateTypeName() string {
@@ -353,7 +349,7 @@ func (fs *filesystem) StateTypeName() string {
 func (fs *filesystem) StateFields() []string {
 	return []string{
 		"vfsfs",
-		"memFile",
+		"mfp",
 		"clock",
 		"devMinor",
 		"nextInoMinusOne",
@@ -366,7 +362,7 @@ func (fs *filesystem) beforeSave() {}
 func (fs *filesystem) StateSave(stateSinkObject state.Sink) {
 	fs.beforeSave()
 	stateSinkObject.Save(0, &fs.vfsfs)
-	stateSinkObject.Save(1, &fs.memFile)
+	stateSinkObject.Save(1, &fs.mfp)
 	stateSinkObject.Save(2, &fs.clock)
 	stateSinkObject.Save(3, &fs.devMinor)
 	stateSinkObject.Save(4, &fs.nextInoMinusOne)
@@ -377,7 +373,7 @@ func (fs *filesystem) afterLoad() {}
 
 func (fs *filesystem) StateLoad(stateSourceObject state.Source) {
 	stateSourceObject.Load(0, &fs.vfsfs)
-	stateSourceObject.Load(1, &fs.memFile)
+	stateSourceObject.Load(1, &fs.mfp)
 	stateSourceObject.Load(2, &fs.clock)
 	stateSourceObject.Load(3, &fs.devMinor)
 	stateSourceObject.Load(4, &fs.nextInoMinusOne)