Add basic stateify annotations.

Updates #1663

PiperOrigin-RevId: 333539293

pkg/sentry/devices/memdev/full.go

@@ -24,6 +24,8 @@ import (
 const fullDevMinor = 7
 
 // fullDevice implements vfs.Device for /dev/full.
+//
+// +stateify savable
 type fullDevice struct{}
 
 // Open implements vfs.Device.Open.
@@ -38,6 +40,8 @@ func (fullDevice) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, op
 }
 
 // fullFD implements vfs.FileDescriptionImpl for /dev/full.
+//
+// +stateify savable
 type fullFD struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl

pkg/sentry/devices/memdev/null.go

@@ -25,6 +25,8 @@ import (
 const nullDevMinor = 3
 
 // nullDevice implements vfs.Device for /dev/null.
+//
+// +stateify savable
 type nullDevice struct{}
 
 // Open implements vfs.Device.Open.
@@ -39,6 +41,8 @@ func (nullDevice) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, op
 }
 
 // nullFD implements vfs.FileDescriptionImpl for /dev/null.
+//
+// +stateify savable
 type nullFD struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl

pkg/sentry/devices/memdev/random.go

@@ -30,6 +30,8 @@ const (
 )
 
 // randomDevice implements vfs.Device for /dev/random and /dev/urandom.
+//
+// +stateify savable
 type randomDevice struct{}
 
 // Open implements vfs.Device.Open.
@@ -44,6 +46,8 @@ func (randomDevice) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry,
 }
 
 // randomFD implements vfs.FileDescriptionImpl for /dev/random.
+//
+// +stateify savable
 type randomFD struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl

pkg/sentry/devices/memdev/zero.go

@@ -27,6 +27,8 @@ import (
 const zeroDevMinor = 5
 
 // zeroDevice implements vfs.Device for /dev/zero.
+//
+// +stateify savable
 type zeroDevice struct{}
 
 // Open implements vfs.Device.Open.
@@ -41,6 +43,8 @@ func (zeroDevice) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, op
 }
 
 // zeroFD implements vfs.FileDescriptionImpl for /dev/zero.
+//
+// +stateify savable
 type zeroFD struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl

pkg/sentry/devices/ttydev/ttydev.go

@@ -30,6 +30,8 @@ const (
 )
 
 // ttyDevice implements vfs.Device for /dev/tty.
+//
+// +stateify savable
 type ttyDevice struct{}
 
 // Open implements vfs.Device.Open.

pkg/sentry/fsimpl/devpts/devpts.go

@@ -35,6 +35,8 @@ import (
 const Name = "devpts"
 
 // FilesystemType implements vfs.FilesystemType.
+//
+// +stateify savable
 type FilesystemType struct{}
 
 // Name implements vfs.FilesystemType.Name.
@@ -58,6 +60,7 @@ func (fstype FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
 	return fs.Filesystem.VFSFilesystem(), root.VFSDentry(), nil
 }
 
+// +stateify savable
 type filesystem struct {
 	kernfs.Filesystem
 
@@ -110,6 +113,8 @@ func (fs *filesystem) Release(ctx context.Context) {
 }
 
 // rootInode is the root directory inode for the devpts mounts.
+//
+// +stateify savable
 type rootInode struct {
 	implStatFS
 	kernfs.AlwaysValid
@@ -131,7 +136,7 @@ type rootInode struct {
 	root *rootInode
 
 	// mu protects the fields below.
-	mu sync.Mutex
+	mu sync.Mutex `state:"nosave"`
 
 	// replicas maps pty ids to replica inodes.
 	replicas map[uint32]*replicaInode
@@ -242,6 +247,7 @@ func (i *rootInode) DecRef(context.Context) {
 	i.rootInodeRefs.DecRef(i.Destroy)
 }
 
+// +stateify savable
 type implStatFS struct{}
 
 // StatFS implements kernfs.Inode.StatFS.

pkg/sentry/fsimpl/devpts/master.go

@@ -31,6 +31,8 @@ import (
 )
 
 // masterInode is the inode for the master end of the Terminal.
+//
+// +stateify savable
 type masterInode struct {
 	implStatFS
 	kernfs.InodeAttrs
@@ -89,6 +91,7 @@ func (mi *masterInode) SetStat(ctx context.Context, vfsfs *vfs.Filesystem, creds
 	return mi.InodeAttrs.SetStat(ctx, vfsfs, creds, opts)
 }
 
+// +stateify savable
 type masterFileDescription struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl

pkg/sentry/fsimpl/devpts/replica.go

@@ -30,6 +30,8 @@ import (
 )
 
 // replicaInode is the inode for the replica end of the Terminal.
+//
+// +stateify savable
 type replicaInode struct {
 	implStatFS
 	kernfs.InodeAttrs
@@ -95,6 +97,7 @@ func (si *replicaInode) SetStat(ctx context.Context, vfsfs *vfs.Filesystem, cred
 	return si.InodeAttrs.SetStat(ctx, vfsfs, creds, opts)
 }
 
+// +stateify savable
 type replicaFileDescription struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl

pkg/sentry/fsimpl/devtmpfs/devtmpfs.go

@@ -33,8 +33,10 @@ import (
 const Name = "devtmpfs"
 
 // FilesystemType implements vfs.FilesystemType.
+//
+// +stateify savable
 type FilesystemType struct {
-	initOnce sync.Once
+	initOnce sync.Once `state:"nosave"` // FIXME(gvisor.dev/issue/1664): not yet supported.
 	initErr  error
 
 	// fs is the tmpfs filesystem that backs all mounts of this FilesystemType.

pkg/sentry/fsimpl/eventfd/eventfd.go

@@ -33,6 +33,8 @@ import (
 // EventFileDescription implements vfs.FileDescriptionImpl for file-based event
 // notification (eventfd). Eventfds are usually internal to the Sentry but in
 // certain situations they may be converted into a host-backed eventfd.
+//
+// +stateify savable
 type EventFileDescription struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl

pkg/sentry/fsimpl/ext/dentry.go

@@ -20,6 +20,8 @@ import (
 )
 
 // dentry implements vfs.DentryImpl.
+//
+// +stateify savable
 type dentry struct {
 	vfsd vfs.Dentry
 

pkg/sentry/fsimpl/ext/directory.go

@@ -28,6 +28,8 @@ import (
 )
 
 // directory represents a directory inode. It holds the childList in memory.
+//
+// +stateify savable
 type directory struct {
 	inode inode
 
@@ -39,7 +41,7 @@ type directory struct {
 	// Lock Order (outermost locks must be taken first):
 	//   directory.mu
 	//     filesystem.mu
-	mu sync.Mutex
+	mu sync.Mutex `state:"nosave"`
 
 	// childList is a list containing (1) child dirents and (2) fake dirents
 	// (with diskDirent == nil) that represent the iteration position of
@@ -120,6 +122,8 @@ func (i *inode) isDir() bool {
 }
 
 // dirent is the directory.childList node.
+//
+// +stateify savable
 type dirent struct {
 	diskDirent disklayout.Dirent
 
@@ -129,6 +133,8 @@ type dirent struct {
 
 // directoryFD represents a directory file description. It implements
 // vfs.FileDescriptionImpl.
+//
+// +stateify savable
 type directoryFD struct {
 	fileDescription
 	vfs.DirectoryFileDescriptionDefaultImpl

pkg/sentry/fsimpl/ext/ext.go

@@ -34,6 +34,8 @@ import (
 const Name = "ext"
 
 // FilesystemType implements vfs.FilesystemType.
+//
+// +stateify savable
 type FilesystemType struct{}
 
 // Compiles only if FilesystemType implements vfs.FilesystemType.

pkg/sentry/fsimpl/ext/extent_file.go

@@ -24,6 +24,8 @@ import (
 )
 
 // extentFile is a type of regular file which uses extents to store file data.
+//
+// +stateify savable
 type extentFile struct {
 	regFile regularFile
 

pkg/sentry/fsimpl/ext/filesystem.go

@@ -38,11 +38,13 @@ var (
 )
 
 // filesystem implements vfs.FilesystemImpl.
+//
+// +stateify savable
 type filesystem struct {
 	vfsfs vfs.Filesystem
 
 	// mu serializes changes to the Dentry tree.
-	mu sync.RWMutex
+	mu sync.RWMutex `state:"nosave"`
 
 	// dev represents the underlying fs device. It does not require protection
 	// because io.ReaderAt permits concurrent read calls to it. It translates to

pkg/sentry/fsimpl/ext/inode.go

@@ -37,6 +37,8 @@ import (
 //           |-- regular--
 //                       |-- extent file
 //                       |-- block map file
+//
+// +stateify savable
 type inode struct {
 	// refs is a reference count. refs is accessed using atomic memory operations.
 	refs int64

pkg/sentry/fsimpl/ext/regular_file.go

@@ -31,6 +31,8 @@ import (
 // regularFile represents a regular file's inode. This too follows the
 // inheritance pattern prevelant in the vfs layer described in
 // pkg/sentry/vfs/README.md.
+//
+// +stateify savable
 type regularFile struct {
 	inode inode
 
@@ -67,6 +69,8 @@ func (in *inode) isRegular() bool {
 
 // directoryFD represents a directory file description. It implements
 // vfs.FileDescriptionImpl.
+//
+// +stateify savable
 type regularFileFD struct {
 	fileDescription
 	vfs.LockFD
@@ -75,7 +79,7 @@ type regularFileFD struct {
 	off int64
 
 	// offMu serializes operations that may mutate off.
-	offMu sync.Mutex
+	offMu sync.Mutex `state:"nosave"`
 }
 
 // Release implements vfs.FileDescriptionImpl.Release.

pkg/sentry/fsimpl/ext/symlink.go

@@ -23,6 +23,8 @@ import (
 )
 
 // symlink represents a symlink inode.
+//
+// +stateify savable
 type symlink struct {
 	inode  inode
 	target string // immutable
@@ -64,6 +66,8 @@ func (in *inode) isSymlink() bool {
 // symlinkFD represents a symlink file description and implements
 // vfs.FileDescriptionImpl. which may only be used if open options contains
 // O_PATH. For this reason most of the functions return EBADF.
+//
+// +stateify savable
 type symlinkFD struct {
 	fileDescription
 	vfs.NoLockFD

pkg/sentry/fsimpl/fuse/connection.go

@@ -39,15 +39,18 @@ const (
 )
 
 // connection is the struct by which the sentry communicates with the FUSE server daemon.
+//
 // Lock order:
 // - conn.fd.mu
 // - conn.mu
 // - conn.asyncMu
+//
+// +stateify savable
 type connection struct {
 	fd *DeviceFD
 
 	// mu protects access to struct memebers.
-	mu sync.Mutex
+	mu sync.Mutex `state:"nosave"`
 
 	// attributeVersion is the version of connection's attributes.
 	attributeVersion uint64
@@ -75,7 +78,7 @@ type connection struct {
 	initialized int32
 
 	// initializedChan is used to block requests before initialization.
-	initializedChan chan struct{}
+	initializedChan chan struct{} `state:".(bool)"`
 
 	// connected (connection established) when a new FUSE file system is created.
 	// Set to false when:
@@ -113,7 +116,7 @@ type connection struct {
 	// i.e. `!request.noReply`
 
 	// asyncMu protects the async request fields.
-	asyncMu sync.Mutex
+	asyncMu sync.Mutex `state:"nosave"`
 
 	// asyncNum is the number of async requests.
 	// Protected by asyncMu.
@@ -174,6 +177,22 @@ type connection struct {
 	noOpen bool
 }
 
+func (conn *connection) saveInitializedChan() bool {
+	select {
+	case <-conn.initializedChan:
+		return true // Closed.
+	default:
+		return false // Not closed.
+	}
+}
+
+func (conn *connection) loadInitializedChan(closed bool) {
+	conn.initializedChan = make(chan struct{}, 1)
+	if closed {
+		close(conn.initializedChan)
+	}
+}
+
 // newFUSEConnection creates a FUSE connection to fd.
 func newFUSEConnection(_ context.Context, fd *vfs.FileDescription, opts *filesystemOptions) (*connection, error) {
 	// Mark the device as ready so it can be used. /dev/fuse can only be used if the FD was used to

pkg/sentry/fsimpl/fuse/dev.go

@@ -31,6 +31,8 @@ import (
 const fuseDevMinor = 229
 
 // fuseDevice implements vfs.Device for /dev/fuse.
+//
+// +stateify savable
 type fuseDevice struct{}
 
 // Open implements vfs.Device.Open.
@@ -49,6 +51,8 @@ func (fuseDevice) Open(ctx context.Context, mnt *vfs.Mount, vfsd *vfs.Dentry, op
 }
 
 // DeviceFD implements vfs.FileDescriptionImpl for /dev/fuse.
+//
+// +stateify savable
 type DeviceFD struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl
@@ -79,7 +83,7 @@ type DeviceFD struct {
 	writeCursorFR *futureResponse
 
 	// mu protects all the queues, maps, buffers and cursors and nextOpID.
-	mu sync.Mutex
+	mu sync.Mutex `state:"nosave"`
 
 	// waitQueue is used to notify interested parties when the device becomes
 	// readable or writable.
@@ -88,12 +92,20 @@ type DeviceFD struct {
 	// fullQueueCh is a channel used to synchronize the readers with the writers.
 	// Writers (inbound requests to the filesystem) block if there are too many
 	// unprocessed in-flight requests.
-	fullQueueCh chan struct{}
+	fullQueueCh chan struct{} `state:".(int)"`
 
 	// fs is the FUSE filesystem that this FD is being used for.
 	fs *filesystem
 }
 
+func (fd *DeviceFD) saveFullQueueCh() int {
+	return cap(fd.fullQueueCh)
+}
+
+func (fd *DeviceFD) loadFullQueueCh(capacity int) {
+	fd.fullQueueCh = make(chan struct{}, capacity)
+}
+
 // Release implements vfs.FileDescriptionImpl.Release.
 func (fd *DeviceFD) Release(ctx context.Context) {
 	if fd.fs != nil {

pkg/sentry/fsimpl/fuse/fusefs.go

@@ -41,8 +41,11 @@ const Name = "fuse"
 const maxActiveRequestsDefault = 10000
 
 // FilesystemType implements vfs.FilesystemType.
+//
+// +stateify savable
 type FilesystemType struct{}
 
+// +stateify savable
 type filesystemOptions struct {
 	// userID specifies the numeric uid of the mount owner.
 	// This option should not be specified by the filesystem owner.
@@ -73,6 +76,8 @@ type filesystemOptions struct {
 }
 
 // filesystem implements vfs.FilesystemImpl.
+//
+// +stateify savable
 type filesystem struct {
 	kernfs.Filesystem
 	devMinor uint32
@@ -240,6 +245,8 @@ func (fs *filesystem) Release(ctx context.Context) {
 }
 
 // inode implements kernfs.Inode.
+//
+// +stateify savable
 type inode struct {
 	inodeRefs
 	kernfs.InodeAttrs

pkg/sentry/fsimpl/gofer/directory.go

@@ -117,11 +117,12 @@ func (d *dentry) createSyntheticChildLocked(opts *createSyntheticOpts) {
 	d.syntheticChildren++
 }
 
+// +stateify savable
 type directoryFD struct {
 	fileDescription
 	vfs.DirectoryFileDescriptionDefaultImpl
 
-	mu      sync.Mutex
+	mu      sync.Mutex `state:"nosave"`
 	off     int64
 	dirents []vfs.Dirent
 }

pkg/sentry/fsimpl/gofer/gofer.go

@@ -62,9 +62,13 @@ import (
 const Name = "9p"
 
 // FilesystemType implements vfs.FilesystemType.
+//
+// +stateify savable
 type FilesystemType struct{}
 
 // filesystem implements vfs.FilesystemImpl.
+//
+// +stateify savable
 type filesystem struct {
 	vfsfs vfs.Filesystem
 
@@ -77,7 +81,7 @@ type filesystem struct {
 	iopts InternalFilesystemOptions
 
 	// client is the client used by this filesystem. client is immutable.
-	client *p9.Client
+	client *p9.Client `state:"nosave"` // FIXME(gvisor.dev/issue/1663): not yet supported.
 
 	// clock is a realtime clock used to set timestamps in file operations.
 	clock ktime.Clock
@@ -95,7 +99,7 @@ type filesystem struct {
 	// reference count (such that it is usable as vfs.ResolvingPath.Start() or
 	// is reachable from its children), or if it is a child dentry (such that
 	// it is reachable from its parent).
-	renameMu sync.RWMutex
+	renameMu sync.RWMutex `state:"nosave"`
 
 	// cachedDentries contains all dentries with 0 references. (Due to race
 	// conditions, it may also contain dentries with non-zero references.)
@@ -107,7 +111,7 @@ type filesystem struct {
 	// syncableDentries contains all dentries in this filesystem for which
 	// !dentry.file.isNil(). specialFileFDs contains all open specialFileFDs.
 	// These fields are protected by syncMu.
-	syncMu           sync.Mutex
+	syncMu           sync.Mutex `state:"nosave"`
 	syncableDentries map[*dentry]struct{}
 	specialFileFDs   map[*specialFileFD]struct{}
 
@@ -120,6 +124,8 @@ type filesystem struct {
 // dentries, it comes from QID.Path from the 9P server. Synthetic dentries
 // have have their inodeNumber generated sequentially, with the MSB reserved to
 // prevent conflicts with regular dentries.
+//
+// +stateify savable
 type inodeNumber uint64
 
 // Reserve MSB for synthetic mounts.
@@ -132,6 +138,7 @@ func inoFromPath(path uint64) inodeNumber {
 	return inodeNumber(path &^ syntheticInoMask)
 }
 
+// +stateify savable
 type filesystemOptions struct {
 	// "Standard" 9P options.
 	fd      int
@@ -177,6 +184,8 @@ type filesystemOptions struct {
 
 // InteropMode controls the client's interaction with other remote filesystem
 // users.
+//
+// +stateify savable
 type InteropMode uint32
 
 const (
@@ -235,6 +244,8 @@ const (
 
 // InternalFilesystemOptions may be passed as
 // vfs.GetFilesystemOptions.InternalData to FilesystemType.GetFilesystem.
+//
+// +stateify savable
 type InternalFilesystemOptions struct {
 	// If LeakConnection is true, do not close the connection to the server
 	// when the Filesystem is released. This is necessary for deployments in
@@ -534,6 +545,8 @@ func (fs *filesystem) Release(ctx context.Context) {
 }
 
 // dentry implements vfs.DentryImpl.
+//
+// +stateify savable
 type dentry struct {
 	vfsd vfs.Dentry
 
@@ -563,7 +576,7 @@ type dentry struct {
 	// If file.isNil(), this dentry represents a synthetic file, i.e. a file
 	// that does not exist on the remote filesystem. As of this writing, the
 	// only files that can be synthetic are sockets, pipes, and directories.
-	file p9file
+	file p9file `state:"nosave"` // FIXME(gvisor.dev/issue/1663): not yet supported.
 
 	// If deleted is non-zero, the file represented by this dentry has been
 	// deleted. deleted is accessed using atomic memory operations.
@@ -575,7 +588,7 @@ type dentry struct {
 	cached bool
 	dentryEntry
 
-	dirMu sync.Mutex
+	dirMu sync.Mutex `state:"nosave"`
 
 	// If this dentry represents a directory, children contains:
 	//
@@ -607,7 +620,7 @@ type dentry struct {
 	// To mutate:
 	//   - Lock metadataMu and use atomic operations to update because we might
 	//     have atomic readers that don't hold the lock.
-	metadataMu sync.Mutex
+	metadataMu sync.Mutex  `state:"nosave"`
 	ino        inodeNumber // immutable
 	mode       uint32      // type is immutable, perms are mutable
 	uid        uint32      // auth.KUID, but stored as raw uint32 for sync/atomic
@@ -638,7 +651,7 @@ type dentry struct {
 	// other metadata fields.
 	nlink uint32
 
-	mapsMu sync.Mutex
+	mapsMu sync.Mutex `state:"nosave"`
 
 	// If this dentry represents a regular file, mappings tracks mappings of
 	// the file into memmap.MappingSpaces. mappings is protected by mapsMu.
@@ -662,12 +675,12 @@ type dentry struct {
 	// either p9.File transitions from closed (isNil() == true) to open
 	// (isNil() == false), it may be mutated with handleMu locked, but cannot
 	// be closed until the dentry is destroyed.
-	handleMu  sync.RWMutex
-	readFile  p9file
-	writeFile p9file
+	handleMu  sync.RWMutex `state:"nosave"`
+	readFile  p9file       `state:"nosave"` // FIXME(gvisor.dev/issue/1663): not yet supported.
+	writeFile p9file       `state:"nosave"` // FIXME(gvisor.dev/issue/1663): not yet supported.
 	hostFD    int32
 
-	dataMu sync.RWMutex
+	dataMu sync.RWMutex `state:"nosave"`
 
 	// If this dentry represents a regular file that is client-cached, cache
 	// maps offsets into the cached file to offsets into
@@ -1627,12 +1640,14 @@ func (d *dentry) decLinks() {
 
 // fileDescription is embedded by gofer implementations of
 // vfs.FileDescriptionImpl.
+//
+// +stateify savable
 type fileDescription struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl
 	vfs.LockFD
 
-	lockLogging sync.Once
+	lockLogging sync.Once `state:"nosave"` // FIXME(gvisor.dev/issue/1663): not yet supported.
 }
 
 func (fd *fileDescription) filesystem() *filesystem {

pkg/sentry/fsimpl/gofer/handle.go

@@ -25,6 +25,8 @@ import (
 
 // handle represents a remote "open file descriptor", consisting of an opened
 // fid (p9.File) and optionally a host file descriptor.
+//
+// These are explicitly not savable.
 type handle struct {
 	file p9file
 	fd   int32 // -1 if unavailable

pkg/sentry/fsimpl/gofer/regular_file.go

@@ -39,11 +39,12 @@ func (d *dentry) isRegularFile() bool {
 	return d.fileType() == linux.S_IFREG
 }
 
+// +stateify savable
 type regularFileFD struct {
 	fileDescription
 
 	// off is the file offset. off is protected by mu.
-	mu  sync.Mutex
+	mu  sync.Mutex `state:"nosave"`
 	off int64
 }
 
@@ -898,6 +899,8 @@ func (d *dentry) Evict(ctx context.Context, er pgalloc.EvictableRange) {
 // dentryPlatformFile is only used when a host FD representing the remote file
 // is available (i.e. dentry.hostFD >= 0), and that FD is used for application
 // memory mappings (i.e. !filesystem.opts.forcePageCache).
+//
+// +stateify savable
 type dentryPlatformFile struct {
 	*dentry
 
@@ -910,7 +913,7 @@ type dentryPlatformFile struct {
 	hostFileMapper fsutil.HostFileMapper
 
 	// hostFileMapperInitOnce is used to lazily initialize hostFileMapper.
-	hostFileMapperInitOnce sync.Once
+	hostFileMapperInitOnce sync.Once `state:"nosave"` // FIXME(gvisor.dev/issue/1663): not yet supported.
 }
 
 // IncRef implements memmap.File.IncRef.

pkg/sentry/fsimpl/gofer/socket.go

@@ -36,12 +36,14 @@ func (d *dentry) isSocket() bool {
 // An endpoint's lifetime is the time between when filesystem.BoundEndpointAt()
 // is called and either BoundEndpoint.BidirectionalConnect or
 // BoundEndpoint.UnidirectionalConnect is called.
+//
+// +stateify savable
 type endpoint struct {
 	// dentry is the filesystem dentry which produced this endpoint.
 	dentry *dentry
 
 	// file is the p9 file that contains a single unopened fid.
-	file p9.File
+	file p9.File `state:"nosave"` // FIXME(gvisor.dev/issue/1663): not yet supported.
 
 	// path is the sentry path where this endpoint is bound.
 	path string

pkg/sentry/fsimpl/gofer/special_file.go

@@ -34,11 +34,13 @@ import (
 // special files, and (when filesystemOptions.regularFilesUseSpecialFileFD is
 // in effect) regular files. specialFileFD differs from regularFileFD by using
 // per-FD handles instead of shared per-dentry handles, and never buffering I/O.
+//
+// +stateify savable
 type specialFileFD struct {
 	fileDescription
 
 	// handle is used for file I/O. handle is immutable.
-	handle handle
+	handle handle `state:"nosave"` // FIXME(gvisor.dev/issue/1663): not yet supported.
 
 	// isRegularFile is true if this FD represents a regular file which is only
 	// possible when filesystemOptions.regularFilesUseSpecialFileFD is in
@@ -56,7 +58,7 @@ type specialFileFD struct {
 	queue     waiter.Queue
 
 	// If seekable is true, off is the file offset. off is protected by mu.
-	mu  sync.Mutex
+	mu  sync.Mutex `state:"nosave"`
 	off int64
 }
 

pkg/sentry/fsimpl/host/host.go

@@ -137,6 +137,8 @@ func ImportFD(ctx context.Context, mnt *vfs.Mount, hostFD int, isTTY bool) (*vfs
 }
 
 // filesystemType implements vfs.FilesystemType.
+//
+// +stateify savable
 type filesystemType struct{}
 
 // GetFilesystem implements vfs.FilesystemType.GetFilesystem.
@@ -166,6 +168,8 @@ func NewFilesystem(vfsObj *vfs.VirtualFilesystem) (*vfs.Filesystem, error) {
 }
 
 // filesystem implements vfs.FilesystemImpl.
+//
+// +stateify savable
 type filesystem struct {
 	kernfs.Filesystem
 
@@ -185,6 +189,8 @@ func (fs *filesystem) PrependPath(ctx context.Context, vfsroot, vd vfs.VirtualDe
 }
 
 // inode implements kernfs.Inode.
+//
+// +stateify savable
 type inode struct {
 	kernfs.InodeNoStatFS
 	kernfs.InodeNotDirectory
@@ -233,7 +239,7 @@ type inode struct {
 	canMap bool
 
 	// mapsMu protects mappings.
-	mapsMu sync.Mutex
+	mapsMu sync.Mutex `state:"nosave"`
 
 	// If canMap is true, mappings tracks mappings of hostFD into
 	// memmap.MappingSpaces.
@@ -511,6 +517,8 @@ func (i *inode) open(ctx context.Context, d *kernfs.Dentry, mnt *vfs.Mount, flag
 }
 
 // fileDescription is embedded by host fd implementations of FileDescriptionImpl.
+//
+// +stateify savable
 type fileDescription struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl
@@ -525,7 +533,7 @@ type fileDescription struct {
 	inode *inode
 
 	// offsetMu protects offset.
-	offsetMu sync.Mutex
+	offsetMu sync.Mutex `state:"nosave"`
 
 	// offset specifies the current file offset. It is only meaningful when
 	// inode.seekable is true.

pkg/sentry/fsimpl/host/mmap.go

@@ -27,11 +27,13 @@ import (
 // cannot implement both kernfs.Inode.IncRef and memmap.File.IncRef.
 //
 // inodePlatformFile should only be used if inode.canMap is true.
+//
+// +stateify savable
 type inodePlatformFile struct {
 	*inode
 
 	// fdRefsMu protects fdRefs.
-	fdRefsMu sync.Mutex
+	fdRefsMu sync.Mutex `state:"nosave"`
 
 	// fdRefs counts references on memmap.File offsets. It is used solely for
 	// memory accounting.
@@ -41,7 +43,7 @@ type inodePlatformFile struct {
 	fileMapper fsutil.HostFileMapper
 
 	// fileMapperInitOnce is used to lazily initialize fileMapper.
-	fileMapperInitOnce sync.Once
+	fileMapperInitOnce sync.Once `state:"nosave"` // FIXME(gvisor.dev/issue/1663): not yet supported.
 }
 
 // IncRef implements memmap.File.IncRef.

pkg/sentry/fsimpl/host/tty.go

@@ -30,6 +30,8 @@ import (
 
 // TTYFileDescription implements vfs.FileDescriptionImpl for a host file
 // descriptor that wraps a TTY FD.
+//
+// +stateify savable
 type TTYFileDescription struct {
 	fileDescription
 

pkg/sentry/fsimpl/kernfs/fd_impl_util.go

@@ -29,6 +29,8 @@ import (
 )
 
 // SeekEndConfig describes the SEEK_END behaviour for FDs.
+//
+// +stateify savable
 type SeekEndConfig int
 
 // Constants related to SEEK_END behaviour for FDs.
@@ -41,6 +43,8 @@ const (
 )
 
 // GenericDirectoryFDOptions contains configuration for a GenericDirectoryFD.
+//
+// +stateify savable
 type GenericDirectoryFDOptions struct {
 	SeekEnd SeekEndConfig
 }
@@ -56,6 +60,8 @@ type GenericDirectoryFDOptions struct {
 // Must be initialize with Init before first use.
 //
 // Lock ordering: mu => children.mu.
+//
+// +stateify savable
 type GenericDirectoryFD struct {
 	vfs.FileDescriptionDefaultImpl
 	vfs.DirectoryFileDescriptionDefaultImpl
@@ -68,7 +74,7 @@ type GenericDirectoryFD struct {
 	children *OrderedChildren
 
 	// mu protects the fields below.
-	mu sync.Mutex
+	mu sync.Mutex `state:"nosave"`
 
 	// off is the current directory offset. Protected by "mu".
 	off int64

pkg/sentry/fsimpl/kernfs/inode_impl_util.go

@@ -31,6 +31,8 @@ import (
 // count for inodes, performing no extra actions when references are obtained or
 // released. This is suitable for simple file inodes that don't reference any
 // resources.
+//
+// +stateify savable
 type InodeNoopRefCount struct {
 }
 
@@ -50,6 +52,8 @@ func (InodeNoopRefCount) TryIncRef() bool {
 // InodeDirectoryNoNewChildren partially implements the Inode interface.
 // InodeDirectoryNoNewChildren represents a directory inode which does not
 // support creation of new children.
+//
+// +stateify savable
 type InodeDirectoryNoNewChildren struct{}
 
 // NewFile implements Inode.NewFile.
@@ -81,6 +85,8 @@ func (InodeDirectoryNoNewChildren) NewNode(context.Context, string, vfs.MknodOpt
 // inodeDirectory and inodeDynamicDirectory sub interfaces. Inodes that do not
 // represent directories can embed this to provide no-op implementations for
 // directory-related functions.
+//
+// +stateify savable
 type InodeNotDirectory struct {
 }
 
@@ -149,6 +155,8 @@ func (InodeNotDirectory) Valid(context.Context) bool {
 // dymanic entries (i.e. entries that are not "hashed" into the
 // vfs.Dentry.children) can embed this to provide no-op implementations for
 // functions related to dynamic entries.
+//
+// +stateify savable
 type InodeNoDynamicLookup struct{}
 
 // Lookup implements Inode.Lookup.
@@ -169,6 +177,8 @@ func (InodeNoDynamicLookup) Valid(ctx context.Context) bool {
 // InodeNotSymlink partially implements the Inode interface, specifically the
 // inodeSymlink sub interface. All inodes that are not symlinks may embed this
 // to return the appropriate errors from symlink-related functions.
+//
+// +stateify savable
 type InodeNotSymlink struct{}
 
 // Readlink implements Inode.Readlink.
@@ -186,6 +196,8 @@ func (InodeNotSymlink) Getlink(context.Context, *vfs.Mount) (vfs.VirtualDentry,
 // inode attributes.
 //
 // Must be initialized by Init prior to first use.
+//
+// +stateify savable
 type InodeAttrs struct {
 	devMajor uint32
 	devMinor uint32
@@ -330,6 +342,7 @@ func (a *InodeAttrs) DecLinks() {
 	}
 }
 
+// +stateify savable
 type slot struct {
 	Name   string
 	Dentry *vfs.Dentry
@@ -337,6 +350,8 @@ type slot struct {
 }
 
 // OrderedChildrenOptions contains initialization options for OrderedChildren.
+//
+// +stateify savable
 type OrderedChildrenOptions struct {
 	// Writable indicates whether vfs.FilesystemImpl methods implemented by
 	// OrderedChildren may modify the tracked children. This applies to
@@ -352,12 +367,14 @@ type OrderedChildrenOptions struct {
 // directories.
 //
 // Must be initialize with Init before first use.
+//
+// +stateify savable
 type OrderedChildren struct {
 	// Can children be modified by user syscalls? It set to false, interface
 	// methods that would modify the children return EPERM. Immutable.
 	writable bool
 
-	mu    sync.RWMutex
+	mu    sync.RWMutex `state:"nosave"`
 	order slotList
 	set   map[string]*slot
 }
@@ -484,6 +501,7 @@ func (o *OrderedChildren) RmDir(ctx context.Context, name string, child *vfs.Den
 	return o.Unlink(ctx, name, child)
 }
 
+// +stateify savable
 type renameAcrossDifferentImplementationsError struct{}
 
 func (renameAcrossDifferentImplementationsError) Error() string {
@@ -542,6 +560,8 @@ func (o *OrderedChildren) nthLocked(i int64) *slot {
 }
 
 // InodeSymlink partially implements Inode interface for symlinks.
+//
+// +stateify savable
 type InodeSymlink struct {
 	InodeNotDirectory
 }
@@ -615,6 +635,8 @@ func (s *StaticDirectory) DecRef(context.Context) {
 }
 
 // AlwaysValid partially implements kernfs.inodeDynamicLookup.
+//
+// +stateify savable
 type AlwaysValid struct{}
 
 // Valid implements kernfs.inodeDynamicLookup.Valid.
@@ -624,6 +646,8 @@ func (*AlwaysValid) Valid(context.Context) bool {
 
 // InodeNoStatFS partially implements the Inode interface, where the client
 // filesystem doesn't support statfs(2).
+//
+// +stateify savable
 type InodeNoStatFS struct{}
 
 // StatFS implements Inode.StatFS.

pkg/sentry/fsimpl/kernfs/kernfs.go

@@ -66,10 +66,12 @@ import (
 // Filesystem mostly implements vfs.FilesystemImpl for a generic in-memory
 // filesystem. Concrete implementations are expected to embed this in their own
 // Filesystem type.
+//
+// +stateify savable
 type Filesystem struct {
 	vfsfs vfs.Filesystem
 
-	droppedDentriesMu sync.Mutex
+	droppedDentriesMu sync.Mutex `state:"nosave"`
 
 	// droppedDentries is a list of dentries waiting to be DecRef()ed. This is
 	// used to defer dentry destruction until mu can be acquired for
@@ -97,7 +99,7 @@ type Filesystem struct {
 	//   defer fs.mu.RUnlock()
 	//   ...
 	//   fs.deferDecRef(dentry)
-	mu sync.RWMutex
+	mu sync.RWMutex `state:"nosave"`
 
 	// nextInoMinusOne is used to to allocate inode numbers on this
 	// filesystem. Must be accessed by atomic operations.
@@ -160,6 +162,8 @@ const (
 // to, and child dentries hold a reference on their parent.
 //
 // Must be initialized by Init prior to first use.
+//
+// +stateify savable
 type Dentry struct {
 	DentryRefs
 
@@ -173,7 +177,7 @@ type Dentry struct {
 	name   string
 
 	// dirMu protects children and the names of child Dentries.
-	dirMu    sync.Mutex
+	dirMu    sync.Mutex `state:"nosave"`
 	children map[string]*Dentry
 
 	inode Inode

pkg/sentry/fsimpl/kernfs/symlink.go

@@ -24,6 +24,8 @@ import (
 
 // StaticSymlink provides an Inode implementation for symlinks that point to
 // a immutable target.
+//
+// +stateify savable
 type StaticSymlink struct {
 	InodeAttrs
 	InodeNoopRefCount

pkg/sentry/fsimpl/overlay/directory.go

@@ -100,12 +100,13 @@ func (d *dentry) collectWhiteoutsForRmdirLocked(ctx context.Context) (map[string
 	return whiteouts, readdirErr
 }
 
+// +stateify savable
 type directoryFD struct {
 	fileDescription
 	vfs.DirectoryFileDescriptionDefaultImpl
 	vfs.DentryMetadataFileDescriptionImpl
 
-	mu      sync.Mutex
+	mu      sync.Mutex `state:"nosave"`
 	off     int64
 	dirents []vfs.Dirent
 }

pkg/sentry/fsimpl/overlay/non_directory.go

@@ -39,6 +39,7 @@ func (d *dentry) readlink(ctx context.Context) (string, error) {
 	})
 }
 
+// +stateify savable
 type nonDirectoryFD struct {
 	fileDescription
 
@@ -47,7 +48,7 @@ type nonDirectoryFD struct {
 	// fileDescription.dentry().upperVD. cachedFlags is the last known value of
 	// cachedFD.StatusFlags(). copiedUp, cachedFD, and cachedFlags are
 	// protected by mu.
-	mu          sync.Mutex
+	mu          sync.Mutex `state:"nosave"`
 	copiedUp    bool
 	cachedFD    *vfs.FileDescription
 	cachedFlags uint32

pkg/sentry/fsimpl/overlay/overlay.go

@@ -51,6 +51,8 @@ import (
 const Name = "overlay"
 
 // FilesystemType implements vfs.FilesystemType.
+//
+// +stateify savable
 type FilesystemType struct{}
 
 // Name implements vfs.FilesystemType.Name.
@@ -60,6 +62,8 @@ func (FilesystemType) Name() string {
 
 // FilesystemOptions may be passed as vfs.GetFilesystemOptions.InternalData to
 // FilesystemType.GetFilesystem.
+//
+// +stateify savable
 type FilesystemOptions struct {
 	// Callers passing FilesystemOptions to
 	// overlay.FilesystemType.GetFilesystem() are responsible for ensuring that
@@ -76,6 +80,8 @@ type FilesystemOptions struct {
 }
 
 // filesystem implements vfs.FilesystemImpl.
+//
+// +stateify savable
 type filesystem struct {
 	vfsfs vfs.Filesystem
 
@@ -98,7 +104,7 @@ type filesystem struct {
 	// renameMu synchronizes renaming with non-renaming operations in order to
 	// ensure consistent lock ordering between dentry.dirMu in different
 	// dentries.
-	renameMu sync.RWMutex
+	renameMu sync.RWMutex `state:"nosave"`
 
 	// lastDirIno is the last inode number assigned to a directory. lastDirIno
 	// is accessed using atomic memory operations.
@@ -367,6 +373,8 @@ func (fs *filesystem) newDirIno() uint64 {
 }
 
 // dentry implements vfs.DentryImpl.
+//
+// +stateify savable
 type dentry struct {
 	vfsd vfs.Dentry
 
@@ -399,7 +407,7 @@ type dentry struct {
 	// and dirents (if not nil) is a cache of dirents as returned by
 	// directoryFDs representing this directory. children is protected by
 	// dirMu.
-	dirMu    sync.Mutex
+	dirMu    sync.Mutex `state:"nosave"`
 	children map[string]*dentry
 	dirents  []vfs.Dirent
 
@@ -409,7 +417,7 @@ type dentry struct {
 	// If !upperVD.Ok(), it can transition to a valid vfs.VirtualDentry (i.e.
 	// be copied up) with copyMu locked for writing; otherwise, it is
 	// immutable. lowerVDs is always immutable.
-	copyMu   sync.RWMutex
+	copyMu   sync.RWMutex `state:"nosave"`
 	upperVD  vfs.VirtualDentry
 	lowerVDs []vfs.VirtualDentry
 
@@ -652,6 +660,8 @@ func (d *dentry) updateAfterSetStatLocked(opts *vfs.SetStatOptions) {
 
 // fileDescription is embedded by overlay implementations of
 // vfs.FileDescriptionImpl.
+//
+// +stateify savable
 type fileDescription struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl

pkg/sentry/fsimpl/pipefs/pipefs.go

@@ -31,6 +31,7 @@ import (
 	"gvisor.dev/gvisor/pkg/usermem"
 )
 
+// +stateify savable
 type filesystemType struct{}
 
 // Name implements vfs.FilesystemType.Name.
@@ -43,6 +44,7 @@ func (filesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.VirtualFile
 	panic("pipefs.filesystemType.GetFilesystem should never be called")
 }
 
+// +stateify savable
 type filesystem struct {
 	kernfs.Filesystem
 
@@ -76,6 +78,8 @@ func (fs *filesystem) PrependPath(ctx context.Context, vfsroot, vd vfs.VirtualDe
 }
 
 // inode implements kernfs.Inode.
+//
+// +stateify savable
 type inode struct {
 	kernfs.InodeNotDirectory
 	kernfs.InodeNotSymlink

pkg/sentry/fsimpl/proc/filesystem.go

@@ -41,6 +41,7 @@ func (FilesystemType) Name() string {
 	return Name
 }
 
+// +stateify savable
 type filesystem struct {
 	kernfs.Filesystem
 
@@ -84,6 +85,8 @@ func (fs *filesystem) Release(ctx context.Context) {
 
 // dynamicInode is an overfitted interface for common Inodes with
 // dynamicByteSource types used in procfs.
+//
+// +stateify savable
 type dynamicInode interface {
 	kernfs.Inode
 	vfs.DynamicBytesSource
@@ -99,6 +102,7 @@ func (fs *filesystem) newDentry(creds *auth.Credentials, ino uint64, perm linux.
 	return d
 }
 
+// +stateify savable
 type staticFile struct {
 	kernfs.DynamicBytesFile
 	vfs.StaticData
@@ -118,10 +122,13 @@ func newStaticDir(creds *auth.Credentials, devMajor, devMinor uint32, ino uint64
 
 // InternalData contains internal data passed in to the procfs mount via
 // vfs.GetFilesystemOptions.InternalData.
+//
+// +stateify savable
 type InternalData struct {
 	Cgroups map[string]string
 }
 
+// +stateify savable
 type implStatFS struct{}
 
 // StatFS implements kernfs.Inode.StatFS.

pkg/sentry/fsimpl/proc/subtasks.go

@@ -116,6 +116,7 @@ func (i *subtasksInode) IterDirents(ctx context.Context, cb vfs.IterDirentsCallb
 	return offset, nil
 }
 
+// +stateify savable
 type subtasksFD struct {
 	kernfs.GenericDirectoryFD
 

pkg/sentry/fsimpl/proc/task.go

@@ -129,6 +129,8 @@ func (i *taskInode) DecRef(context.Context) {
 
 // taskOwnedInode implements kernfs.Inode and overrides inode owner with task
 // effective user and group.
+//
+// +stateify savable
 type taskOwnedInode struct {
 	kernfs.Inode
 

pkg/sentry/fsimpl/proc/task_fds.go

@@ -51,6 +51,7 @@ func taskFDExists(ctx context.Context, t *kernel.Task, fd int32) bool {
 	return true
 }
 
+// +stateify savable
 type fdDir struct {
 	locks vfs.FileLocks
 

pkg/sentry/fsimpl/proc/task_files.go

@@ -785,6 +785,7 @@ func (i *mountsData) Generate(ctx context.Context, buf *bytes.Buffer) error {
 	return nil
 }
 
+// +stateify savable
 type namespaceSymlink struct {
 	kernfs.StaticSymlink
 
@@ -832,6 +833,8 @@ func (s *namespaceSymlink) Getlink(ctx context.Context, mnt *vfs.Mount) (vfs.Vir
 
 // namespaceInode is a synthetic inode created to represent a namespace in
 // /proc/[pid]/ns/*.
+//
+// +stateify savable
 type namespaceInode struct {
 	implStatFS
 	kernfs.InodeAttrs
@@ -865,6 +868,8 @@ func (i *namespaceInode) Open(ctx context.Context, rp *vfs.ResolvingPath, d *ker
 
 // namespace FD is a synthetic file that represents a namespace in
 // /proc/[pid]/ns/*.
+//
+// +stateify savable
 type namespaceFD struct {
 	vfs.FileDescriptionDefaultImpl
 	vfs.LockFD

pkg/sentry/fsimpl/proc/task_net.go

@@ -616,6 +616,7 @@ type netSnmpData struct {
 
 var _ dynamicInode = (*netSnmpData)(nil)
 
+// +stateify savable
 type snmpLine struct {
 	prefix string
 	header string

pkg/sentry/fsimpl/proc/tasks.go

@@ -236,6 +236,8 @@ func (i *tasksInode) DecRef(context.Context) {
 // staticFileSetStat implements a special static file that allows inode
 // attributes to be set. This is to support /proc files that are readonly, but
 // allow attributes to be set.
+//
+// +stateify savable
 type staticFileSetStat struct {
 	dynamicBytesFileSetAttr
 	vfs.StaticData

pkg/sentry/fsimpl/proc/tasks_files.go

@@ -31,6 +31,7 @@ import (
 	"gvisor.dev/gvisor/pkg/usermem"
 )
 
+// +stateify savable
 type selfSymlink struct {
 	implStatFS
 	kernfs.InodeAttrs
@@ -74,6 +75,7 @@ func (*selfSymlink) SetStat(context.Context, *vfs.Filesystem, *auth.Credentials,
 	return syserror.EPERM
 }
 
+// +stateify savable
 type threadSelfSymlink struct {
 	implStatFS
 	kernfs.InodeAttrs
@@ -121,6 +123,8 @@ func (*threadSelfSymlink) SetStat(context.Context, *vfs.Filesystem, *auth.Creden
 // dynamicBytesFileSetAttr implements a special file that allows inode
 // attributes to be set. This is to support /proc files that are readonly, but
 // allow attributes to be set.
+//
+// +stateify savable
 type dynamicBytesFileSetAttr struct {
 	kernfs.DynamicBytesFile
 }
@@ -131,6 +135,8 @@ func (d *dynamicBytesFileSetAttr) SetStat(ctx context.Context, fs *vfs.Filesyste
 }
 
 // cpuStats contains the breakdown of CPU time for /proc/stat.
+//
+// +stateify savable
 type cpuStats struct {
 	// user is time spent in userspace tasks with non-positive niceness.
 	user uint64

pkg/sentry/fsimpl/proc/tasks_sys.go

@@ -31,6 +31,7 @@ import (
 	"gvisor.dev/gvisor/pkg/usermem"
 )
 
+// +stateify savable
 type tcpMemDir int
 
 const (

pkg/sentry/fsimpl/signalfd/signalfd.go

@@ -27,6 +27,8 @@ import (
 )
 
 // SignalFileDescription implements vfs.FileDescriptionImpl for signal fds.
+//
+// +stateify savable
 type SignalFileDescription struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl
@@ -43,7 +45,7 @@ type SignalFileDescription struct {
 	target *kernel.Task
 
 	// mu protects mask.
-	mu sync.Mutex
+	mu sync.Mutex `state:"nosave"`
 
 	// mask is the signal mask. Protected by mu.
 	mask linux.SignalSet

pkg/sentry/fsimpl/sockfs/sockfs.go

@@ -28,6 +28,8 @@ import (
 )
 
 // filesystemType implements vfs.FilesystemType.
+//
+// +stateify savable
 type filesystemType struct{}
 
 // GetFilesystem implements vfs.FilesystemType.GetFilesystem.
@@ -44,6 +46,7 @@ func (filesystemType) Name() string {
 	return "sockfs"
 }
 
+// +stateify savable
 type filesystem struct {
 	kernfs.Filesystem
 
@@ -80,6 +83,8 @@ func (fs *filesystem) PrependPath(ctx context.Context, vfsroot, vd vfs.VirtualDe
 }
 
 // inode implements kernfs.Inode.
+//
+// +stateify savable
 type inode struct {
 	kernfs.InodeAttrs
 	kernfs.InodeNoopRefCount

pkg/sentry/fsimpl/sys/kcov.go

@@ -36,6 +36,8 @@ func (fs *filesystem) newKcovFile(ctx context.Context, creds *auth.Credentials)
 }
 
 // kcovInode implements kernfs.Inode.
+//
+// +stateify savable
 type kcovInode struct {
 	kernfs.InodeAttrs
 	kernfs.InodeNoopRefCount
@@ -63,6 +65,7 @@ func (i *kcovInode) Open(ctx context.Context, rp *vfs.ResolvingPath, d *kernfs.D
 	return &fd.vfsfd, nil
 }
 
+// +stateify savable
 type kcovFD struct {
 	vfs.FileDescriptionDefaultImpl
 	vfs.NoLockFD

pkg/sentry/fsimpl/sys/sys.go

@@ -34,9 +34,13 @@ const Name = "sysfs"
 const defaultSysDirMode = linux.FileMode(0755)
 
 // FilesystemType implements vfs.FilesystemType.
+//
+// +stateify savable
 type FilesystemType struct{}
 
 // filesystem implements vfs.FilesystemImpl.
+//
+// +stateify savable
 type filesystem struct {
 	kernfs.Filesystem
 
@@ -117,6 +121,8 @@ func (fs *filesystem) Release(ctx context.Context) {
 }
 
 // dir implements kernfs.Inode.
+//
+// +stateify savable
 type dir struct {
 	dirRefs
 	kernfs.InodeAttrs
@@ -169,6 +175,8 @@ func (d *dir) StatFS(ctx context.Context, fs *vfs.Filesystem) (linux.Statfs, err
 }
 
 // cpuFile implements kernfs.Inode.
+//
+// +stateify savable
 type cpuFile struct {
 	implStatFS
 	kernfs.DynamicBytesFile
@@ -190,6 +198,7 @@ func (fs *filesystem) newCPUFile(creds *auth.Credentials, maxCores uint, mode li
 	return d
 }
 
+// +stateify savable
 type implStatFS struct{}
 
 // StatFS implements kernfs.Inode.StatFS.

pkg/sentry/fsimpl/timerfd/timerfd.go

@@ -28,6 +28,8 @@ import (
 
 // TimerFileDescription implements vfs.FileDescriptionImpl for timer fds. It also
 // implements ktime.TimerListener.
+//
+// +stateify savable
 type TimerFileDescription struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl

pkg/sentry/fsimpl/tmpfs/device_file.go

@@ -22,6 +22,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
 )
 
+// +stateify savable
 type deviceFile struct {
 	inode inode
 	kind  vfs.DeviceKind

pkg/sentry/fsimpl/tmpfs/directory.go

@@ -25,6 +25,7 @@ import (
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
+// +stateify savable
 type directory struct {
 	// Since directories can't be hard-linked, each directory can only be
 	// associated with a single dentry, which we can store in the directory
@@ -44,7 +45,7 @@ type directory struct {
 	// (with inode == nil) that represent the iteration position of
 	// directoryFDs. childList is used to support directoryFD.IterDirents()
 	// efficiently. childList is protected by iterMu.
-	iterMu    sync.Mutex
+	iterMu    sync.Mutex `state:"nosave"`
 	childList dentryList
 }
 
@@ -86,6 +87,7 @@ func (dir *directory) mayDelete(creds *auth.Credentials, child *dentry) error {
 	return vfs.CheckDeleteSticky(creds, linux.FileMode(atomic.LoadUint32(&dir.inode.mode)), auth.KUID(atomic.LoadUint32(&child.inode.uid)))
 }
 
+// +stateify savable
 type directoryFD struct {
 	fileDescription
 	vfs.DirectoryFileDescriptionDefaultImpl

pkg/sentry/fsimpl/tmpfs/named_pipe.go

@@ -21,6 +21,7 @@ import (
 	"gvisor.dev/gvisor/pkg/usermem"
 )
 
+// +stateify savable
 type namedPipe struct {
 	inode inode
 

pkg/sentry/fsimpl/tmpfs/regular_file.go

@@ -36,6 +36,8 @@ import (
 )
 
 // regularFile is a regular (=S_IFREG) tmpfs file.
+//
+// +stateify savable
 type regularFile struct {
 	inode inode
 
@@ -66,7 +68,7 @@ type regularFile struct {
 	writableMappingPages uint64
 
 	// dataMu protects the fields below.
-	dataMu sync.RWMutex
+	dataMu sync.RWMutex `state:"nosave"`
 
 	// data maps offsets into the file to offsets into memFile that store
 	// the file's data.
@@ -325,13 +327,14 @@ func (*regularFile) InvalidateUnsavable(context.Context) error {
 	return nil
 }
 
+// +stateify savable
 type regularFileFD struct {
 	fileDescription
 
 	// off is the file offset. off is accessed using atomic memory operations.
 	// offMu serializes operations that may mutate off.
 	off   int64
-	offMu sync.Mutex
+	offMu sync.Mutex `state:"nosave"`
 }
 
 // Release implements vfs.FileDescriptionImpl.Release.

pkg/sentry/fsimpl/tmpfs/socket_file.go

@@ -21,6 +21,8 @@ import (
 )
 
 // socketFile is a socket (=S_IFSOCK) tmpfs file.
+//
+// +stateify savable
 type socketFile struct {
 	inode inode
 	ep    transport.BoundEndpoint

pkg/sentry/fsimpl/tmpfs/symlink.go

@@ -19,6 +19,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 )
 
+// +stateify savable
 type symlink struct {
 	inode  inode
 	target string // immutable

pkg/sentry/fsimpl/tmpfs/tmpfs.go

@@ -51,9 +51,13 @@ import (
 const Name = "tmpfs"
 
 // FilesystemType implements vfs.FilesystemType.
+//
+// +stateify savable
 type FilesystemType struct{}
 
 // filesystem implements vfs.FilesystemImpl.
+//
+// +stateify savable
 type filesystem struct {
 	vfsfs vfs.Filesystem
 
@@ -67,7 +71,7 @@ type filesystem struct {
 	devMinor uint32
 
 	// mu serializes changes to the Dentry tree.
-	mu sync.RWMutex
+	mu sync.RWMutex `state:"nosave"`
 
 	nextInoMinusOne uint64 // accessed using atomic memory operations
 }
@@ -78,6 +82,8 @@ func (FilesystemType) Name() string {
 }
 
 // FilesystemOpts is used to pass configuration data to tmpfs.
+//
+// +stateify savable
 type FilesystemOpts struct {
 	// RootFileType is the FileType of the filesystem root. Valid values
 	// are: S_IFDIR, S_IFREG, and S_IFLNK. Defaults to S_IFDIR.
@@ -221,6 +227,8 @@ var globalStatfs = linux.Statfs{
 }
 
 // dentry implements vfs.DentryImpl.
+//
+// +stateify savable
 type dentry struct {
 	vfsd vfs.Dentry
 
@@ -300,6 +308,8 @@ func (d *dentry) Watches() *vfs.Watches {
 func (d *dentry) OnZeroWatches(context.Context) {}
 
 // inode represents a filesystem object.
+//
+// +stateify savable
 type inode struct {
 	// fs is the owning filesystem. fs is immutable.
 	fs *filesystem
@@ -316,12 +326,12 @@ type inode struct {
 
 	// Inode metadata. Writing multiple fields atomically requires holding
 	// mu, othewise atomic operations can be used.
-	mu    sync.Mutex
-	mode  uint32 // file type and mode
-	nlink uint32 // protected by filesystem.mu instead of inode.mu
-	uid   uint32 // auth.KUID, but stored as raw uint32 for sync/atomic
-	gid   uint32 // auth.KGID, but ...
-	ino   uint64 // immutable
+	mu    sync.Mutex `state:"nosave"`
+	mode  uint32     // file type and mode
+	nlink uint32     // protected by filesystem.mu instead of inode.mu
+	uid   uint32     // auth.KUID, but stored as raw uint32 for sync/atomic
+	gid   uint32     // auth.KGID, but ...
+	ino   uint64     // immutable
 
 	// Linux's tmpfs has no concept of btime.
 	atime int64 // nanoseconds
@@ -668,6 +678,8 @@ func (i *inode) checkXattrPermissions(creds *auth.Credentials, name string, ats
 
 // fileDescription is embedded by tmpfs implementations of
 // vfs.FileDescriptionImpl.
+//
+// +stateify savable
 type fileDescription struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl

pkg/sentry/fsimpl/verity/verity.go

@@ -74,9 +74,13 @@ var noCrashOnVerificationFailure bool
 var verityMu sync.RWMutex
 
 // FilesystemType implements vfs.FilesystemType.
+//
+// +stateify savable
 type FilesystemType struct{}
 
 // filesystem implements vfs.FilesystemImpl.
+//
+// +stateify savable
 type filesystem struct {
 	vfsfs vfs.Filesystem
 
@@ -101,11 +105,13 @@ type filesystem struct {
 	// renameMu synchronizes renaming with non-renaming operations in order
 	// to ensure consistent lock ordering between dentry.dirMu in different
 	// dentries.
-	renameMu sync.RWMutex
+	renameMu sync.RWMutex `state:"nosave"`
 }
 
 // InternalFilesystemOptions may be passed as
 // vfs.GetFilesystemOptions.InternalData to FilesystemType.GetFilesystem.
+//
+// +stateify savable
 type InternalFilesystemOptions struct {
 	// RootMerkleFileName is the name of the verity root Merkle tree file.
 	RootMerkleFileName string
@@ -259,6 +265,8 @@ func (fs *filesystem) Release(ctx context.Context) {
 }
 
 // dentry implements vfs.DentryImpl.
+//
+// +stateify savable
 type dentry struct {
 	vfsd vfs.Dentry
 
@@ -285,7 +293,7 @@ type dentry struct {
 	// and dirents (if not nil) is a cache of dirents as returned by
 	// directoryFDs representing this directory. children is protected by
 	// dirMu.
-	dirMu    sync.Mutex
+	dirMu    sync.Mutex `state:"nosave"`
 	children map[string]*dentry
 
 	// lowerVD is the VirtualDentry in the underlying file system.
@@ -429,6 +437,8 @@ func (d *dentry) readlink(ctx context.Context) (string, error) {
 // FileDescription is a wrapper of the underlying lowerFD, with support to build
 // Merkle trees through the Linux fs-verity API to verify contents read from
 // lowerFD.
+//
+// +stateify savable
 type fileDescription struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl

pkg/sentry/kernel/kernel.go

@@ -507,6 +507,10 @@ func (k *Kernel) SaveTo(w wire.Writer) error {
 // flushMountSourceRefs flushes the MountSources for all mounted filesystems
 // and open FDs.
 func (k *Kernel) flushMountSourceRefs(ctx context.Context) error {
+	if VFS2Enabled {
+		return nil // Not relevant.
+	}
+
 	// Flush all mount sources for currently mounted filesystems in each task.
 	flushed := make(map[*fs.MountNamespace]struct{})
 	k.tasks.mu.RLock()
@@ -533,11 +537,6 @@ func (k *Kernel) flushMountSourceRefs(ctx context.Context) error {
 //
 // Precondition: Must be called with the kernel paused.
 func (ts *TaskSet) forEachFDPaused(ctx context.Context, f func(*fs.File, *vfs.FileDescription) error) (err error) {
-	// TODO(gvisor.dev/issue/1663): Add save support for VFS2.
-	if VFS2Enabled {
-		return nil
-	}
-
 	ts.mu.RLock()
 	defer ts.mu.RUnlock()
 	for t := range ts.Root.tids {
@@ -556,6 +555,10 @@ func (ts *TaskSet) forEachFDPaused(ctx context.Context, f func(*fs.File, *vfs.Fi
 
 func (ts *TaskSet) flushWritesToFiles(ctx context.Context) error {
 	// TODO(gvisor.dev/issue/1663): Add save support for VFS2.
+	if VFS2Enabled {
+		return nil
+	}
+
 	return ts.forEachFDPaused(ctx, func(file *fs.File, _ *vfs.FileDescription) error {
 		if flags := file.Flags(); !flags.Write {
 			return nil

pkg/sentry/socket/unix/unix_vfs2.go

@@ -37,6 +37,8 @@ import (
 
 // SocketVFS2 implements socket.SocketVFS2 (and by extension,
 // vfs.FileDescriptionImpl) for Unix sockets.
+//
+// +stateify savable
 type SocketVFS2 struct {
 	vfsfd vfs.FileDescription
 	vfs.FileDescriptionDefaultImpl

pkg/sentry/state/state.go

@@ -61,8 +61,10 @@ func (opts SaveOpts) Save(k *kernel.Kernel, w *watchdog.Watchdog) error {
 	log.Infof("Sandbox save started, pausing all tasks.")
 	k.Pause()
 	k.ReceiveTaskStates()
-	defer k.Unpause()
-	defer log.Infof("Tasks resumed after save.")
+	defer func() {
+		k.Unpause()
+		log.Infof("Tasks resumed after save.")
+	}()
 
 	w.Stop()
 	defer w.Start()

pkg/sentry/vfs/anonfs.go

@@ -52,6 +52,8 @@ const (
 )
 
 // anonFilesystemType implements FilesystemType.
+//
+// +stateify savable
 type anonFilesystemType struct{}
 
 // GetFilesystem implements FilesystemType.GetFilesystem.
@@ -69,12 +71,15 @@ func (anonFilesystemType) Name() string {
 //
 // Since all Dentries in anonFilesystem are non-directories, all FilesystemImpl
 // methods that would require an anonDentry to be a directory return ENOTDIR.
+//
+// +stateify savable
 type anonFilesystem struct {
 	vfsfs Filesystem
 
 	devMinor uint32
 }
 
+// +stateify savable
 type anonDentry struct {
 	vfsd Dentry
 

pkg/sentry/vfs/dentry.go

@@ -89,6 +89,8 @@ func (d *Dentry) Impl() DentryImpl {
 // DentryImpl contains implementation details for a Dentry. Implementations of
 // DentryImpl should contain their associated Dentry by value as their first
 // field.
+//
+// +stateify savable
 type DentryImpl interface {
 	// IncRef increments the Dentry's reference count. A Dentry with a non-zero
 	// reference count must remain coherent with the state of the filesystem.

pkg/sentry/vfs/device.go

@@ -22,6 +22,8 @@ import (
 )
 
 // DeviceKind indicates whether a device is a block or character device.
+//
+// +stateify savable
 type DeviceKind uint32
 
 const (
@@ -44,6 +46,7 @@ func (kind DeviceKind) String() string {
 	}
 }
 
+// +stateify savable
 type devTuple struct {
 	kind  DeviceKind
 	major uint32

pkg/sentry/vfs/epoll.go

@@ -27,6 +27,8 @@ import (
 var epollCycleMu sync.Mutex
 
 // EpollInstance represents an epoll instance, as described by epoll(7).
+//
+// +stateify savable
 type EpollInstance struct {
 	vfsfd FileDescription
 	FileDescriptionDefaultImpl
@@ -38,11 +40,11 @@ type EpollInstance struct {
 
 	// interest is the set of file descriptors that are registered with the
 	// EpollInstance for monitoring. interest is protected by interestMu.
-	interestMu sync.Mutex
+	interestMu sync.Mutex `state:"nosave"`
 	interest   map[epollInterestKey]*epollInterest
 
 	// mu protects fields in registered epollInterests.
-	mu sync.Mutex
+	mu sync.Mutex `state:"nosave"`
 
 	// ready is the set of file descriptors that may be "ready" for I/O. Note
 	// that this must be an ordered list, not a map: "If more than maxevents
@@ -55,6 +57,7 @@ type EpollInstance struct {
 	ready epollInterestList
 }
 
+// +stateify savable
 type epollInterestKey struct {
 	// file is the registered FileDescription. No reference is held on file;
 	// instead, when the last reference is dropped, FileDescription.DecRef()
@@ -67,6 +70,8 @@ type epollInterestKey struct {
 }
 
 // epollInterest represents an EpollInstance's interest in a file descriptor.
+//
+// +stateify savable
 type epollInterest struct {
 	// epoll is the owning EpollInstance. epoll is immutable.
 	epoll *EpollInstance

pkg/sentry/vfs/file_description.go

@@ -37,11 +37,13 @@ import (
 // FileDescription methods require that a reference is held.
 //
 // FileDescription is analogous to Linux's struct file.
+//
+// +stateify savable
 type FileDescription struct {
 	FileDescriptionRefs
 
 	// flagsMu protects statusFlags and asyncHandler below.
-	flagsMu sync.Mutex
+	flagsMu sync.Mutex `state:"nosave"`
 
 	// statusFlags contains status flags, "initialized by open(2) and possibly
 	// modified by fcntl()" - fcntl(2). statusFlags can be read using atomic
@@ -56,7 +58,7 @@ type FileDescription struct {
 
 	// epolls is the set of epollInterests registered for this FileDescription.
 	// epolls is protected by epollMu.
-	epollMu sync.Mutex
+	epollMu sync.Mutex `state:"nosave"`
 	epolls  map[*epollInterest]struct{}
 
 	// vd is the filesystem location at which this FileDescription was opened.
@@ -88,6 +90,8 @@ type FileDescription struct {
 }
 
 // FileDescriptionOptions contains options to FileDescription.Init().
+//
+// +stateify savable
 type FileDescriptionOptions struct {
 	// If AllowDirectIO is true, allow O_DIRECT to be set on the file.
 	AllowDirectIO bool
@@ -451,6 +455,8 @@ type FileDescriptionImpl interface {
 }
 
 // Dirent holds the information contained in struct linux_dirent64.
+//
+// +stateify savable
 type Dirent struct {
 	// Name is the filename.
 	Name string

pkg/sentry/vfs/file_description_impl_util.go

@@ -42,6 +42,8 @@ import (
 // FileDescriptionDefaultImpl may be embedded by implementations of
 // FileDescriptionImpl to obtain implementations of many FileDescriptionImpl
 // methods with default behavior analogous to Linux's.
+//
+// +stateify savable
 type FileDescriptionDefaultImpl struct{}
 
 // OnClose implements FileDescriptionImpl.OnClose analogously to
@@ -166,6 +168,8 @@ func (FileDescriptionDefaultImpl) RemoveXattr(ctx context.Context, name string)
 // DirectoryFileDescriptionDefaultImpl may be embedded by implementations of
 // FileDescriptionImpl that always represent directories to obtain
 // implementations of non-directory I/O methods that return EISDIR.
+//
+// +stateify savable
 type DirectoryFileDescriptionDefaultImpl struct{}
 
 // Allocate implements DirectoryFileDescriptionDefaultImpl.Allocate.
@@ -196,6 +200,8 @@ func (DirectoryFileDescriptionDefaultImpl) Write(ctx context.Context, src userme
 // DentryMetadataFileDescriptionImpl may be embedded by implementations of
 // FileDescriptionImpl for which FileDescriptionOptions.UseDentryMetadata is
 // true to obtain implementations of Stat and SetStat that panic.
+//
+// +stateify savable
 type DentryMetadataFileDescriptionImpl struct{}
 
 // Stat implements FileDescriptionImpl.Stat.
@@ -210,12 +216,16 @@ func (DentryMetadataFileDescriptionImpl) SetStat(ctx context.Context, opts SetSt
 
 // DynamicBytesSource represents a data source for a
 // DynamicBytesFileDescriptionImpl.
+//
+// +stateify savable
 type DynamicBytesSource interface {
 	// Generate writes the file's contents to buf.
 	Generate(ctx context.Context, buf *bytes.Buffer) error
 }
 
 // StaticData implements DynamicBytesSource over a static string.
+//
+// +stateify savable
 type StaticData struct {
 	Data string
 }
@@ -242,14 +252,24 @@ type WritableDynamicBytesSource interface {
 //
 // DynamicBytesFileDescriptionImpl.SetDataSource() must be called before first
 // use.
+//
+// +stateify savable
 type DynamicBytesFileDescriptionImpl struct {
 	data     DynamicBytesSource // immutable
-	mu       sync.Mutex         // protects the following fields
-	buf      bytes.Buffer
+	mu       sync.Mutex         `state:"nosave"` // protects the following fields
+	buf      bytes.Buffer       `state:".([]byte)"`
 	off      int64
 	lastRead int64 // offset at which the last Read, PRead, or Seek ended
 }
 
+func (fd *DynamicBytesFileDescriptionImpl) saveBuf() []byte {
+	return fd.buf.Bytes()
+}
+
+func (fd *DynamicBytesFileDescriptionImpl) loadBuf(p []byte) {
+	fd.buf.Write(p)
+}
+
 // SetDataSource must be called exactly once on fd before first use.
 func (fd *DynamicBytesFileDescriptionImpl) SetDataSource(data DynamicBytesSource) {
 	fd.data = data
@@ -382,6 +402,8 @@ func GenericConfigureMMap(fd *FileDescription, m memmap.Mappable, opts *memmap.M
 
 // LockFD may be used by most implementations of FileDescriptionImpl.Lock*
 // functions. Caller must call Init().
+//
+// +stateify savable
 type LockFD struct {
 	locks *FileLocks
 }
@@ -409,6 +431,8 @@ func (fd *LockFD) UnlockBSD(ctx context.Context, uid fslock.UniqueID) error {
 
 // NoLockFD implements Lock*/Unlock* portion of FileDescriptionImpl interface
 // returning ENOLCK.
+//
+// +stateify savable
 type NoLockFD struct{}
 
 // LockBSD implements vfs.FileDescriptionImpl.LockBSD.

pkg/sentry/vfs/filesystem.go

@@ -506,6 +506,8 @@ type FilesystemImpl interface {
 
 // PrependPathAtVFSRootError is returned by implementations of
 // FilesystemImpl.PrependPath() when they encounter the contextual VFS root.
+//
+// +stateify savable
 type PrependPathAtVFSRootError struct{}
 
 // Error implements error.Error.
@@ -516,6 +518,8 @@ func (PrependPathAtVFSRootError) Error() string {
 // PrependPathAtNonMountRootError is returned by implementations of
 // FilesystemImpl.PrependPath() when they encounter an independent ancestor
 // Dentry that is not the Mount root.
+//
+// +stateify savable
 type PrependPathAtNonMountRootError struct{}
 
 // Error implements error.Error.
@@ -526,6 +530,8 @@ func (PrependPathAtNonMountRootError) Error() string {
 // PrependPathSyntheticError is returned by implementations of
 // FilesystemImpl.PrependPath() for which prepended names do not represent real
 // paths.
+//
+// +stateify savable
 type PrependPathSyntheticError struct{}
 
 // Error implements error.Error.

pkg/sentry/vfs/filesystem_type.go

@@ -55,6 +55,8 @@ type registeredFilesystemType struct {
 
 // RegisterFilesystemTypeOptions contains options to
 // VirtualFilesystem.RegisterFilesystem().
+//
+// +stateify savable
 type RegisterFilesystemTypeOptions struct {
 	// AllowUserMount determines whether users are allowed to mount a file system
 	// of this type, i.e. through mount(2). If AllowUserMount is true, allow calls

pkg/sentry/vfs/genericfstree/genericfstree.go

@@ -27,6 +27,8 @@ import (
 )
 
 // Dentry is a required type parameter that is a struct with the given fields.
+//
+// +stateify savable
 type Dentry struct {
 	// vfsd is the embedded vfs.Dentry corresponding to this vfs.DentryImpl.
 	vfsd vfs.Dentry

pkg/sentry/vfs/inotify.go

@@ -37,6 +37,8 @@ const inotifyEventBaseSize = 16
 //
 // The way events are labelled appears somewhat arbitrary, but they must match
 // Linux so that IN_EXCL_UNLINK behaves as it does in Linux.
+//
+// +stateify savable
 type EventType uint8
 
 // PathEvent and InodeEvent correspond to FSNOTIFY_EVENT_PATH and

pkg/sentry/vfs/lock.go

@@ -33,6 +33,8 @@ import (
 // Note that in Linux these two types of locks are _not_ cooperative, because
 // race and deadlock conditions make merging them prohibitive. We do the same
 // and keep them oblivious to each other.
+//
+// +stateify savable
 type FileLocks struct {
 	// bsd is a set of BSD-style advisory file wide locks, see flock(2).
 	bsd fslock.Locks

pkg/sentry/vfs/mount.go

@@ -65,7 +65,7 @@ type Mount struct {
 	//
 	// Invariant: key.parent != nil iff key.point != nil. key.point belongs to
 	// key.parent.fs.
-	key mountKey
+	key mountKey `state:".(VirtualDentry)"`
 
 	// ns is the namespace in which this Mount was mounted. ns is protected by
 	// VirtualFilesystem.mountMu.
@@ -345,6 +345,7 @@ func (vfs *VirtualFilesystem) UmountAt(ctx context.Context, creds *auth.Credenti
 	return nil
 }
 
+// +stateify savable
 type umountRecursiveOptions struct {
 	// If eager is true, ensure that future calls to Mount.tryIncMountedRef()
 	// on umounted mounts fail.
@@ -414,7 +415,7 @@ func (vfs *VirtualFilesystem) connectLocked(mnt *Mount, vd VirtualDentry, mntns
 		}
 	}
 	mnt.IncRef() // dropped by callers of umountRecursiveLocked
-	mnt.storeKey(vd)
+	mnt.setKey(vd)
 	if vd.mount.children == nil {
 		vd.mount.children = make(map[*Mount]struct{})
 	}
@@ -439,13 +440,13 @@ func (vfs *VirtualFilesystem) connectLocked(mnt *Mount, vd VirtualDentry, mntns
 // * vfs.mounts.seq must be in a writer critical section.
 // * mnt.parent() != nil.
 func (vfs *VirtualFilesystem) disconnectLocked(mnt *Mount) VirtualDentry {
-	vd := mnt.loadKey()
+	vd := mnt.getKey()
 	if checkInvariants {
 		if vd.mount != nil {
 			panic("VFS.disconnectLocked called on disconnected mount")
 		}
 	}
-	mnt.storeKey(VirtualDentry{})
+	mnt.loadKey(VirtualDentry{})
 	delete(vd.mount.children, mnt)
 	atomic.AddUint32(&vd.dentry.mounts, math.MaxUint32) // -1
 	mnt.ns.mountpoints[vd.dentry]--

pkg/sentry/vfs/mount_test.go

@@ -38,7 +38,7 @@ func TestMountTableInsertLookup(t *testing.T) {
 	mt.Init()
 
 	mount := &Mount{}
-	mount.storeKey(VirtualDentry{&Mount{}, &Dentry{}})
+	mount.setKey(VirtualDentry{&Mount{}, &Dentry{}})
 	mt.Insert(mount)
 
 	if m := mt.Lookup(mount.parent(), mount.point()); m != mount {
@@ -79,7 +79,7 @@ const enableComparativeBenchmarks = false
 
 func newBenchMount() *Mount {
 	mount := &Mount{}
-	mount.storeKey(VirtualDentry{&Mount{}, &Dentry{}})
+	mount.loadKey(VirtualDentry{&Mount{}, &Dentry{}})
 	return mount
 }
 
@@ -94,7 +94,7 @@ func BenchmarkMountTableParallelLookup(b *testing.B) {
 				for i := 0; i < numMounts; i++ {
 					mount := newBenchMount()
 					mt.Insert(mount)
-					keys = append(keys, mount.loadKey())
+					keys = append(keys, mount.saveKey())
 				}
 
 				var ready sync.WaitGroup
@@ -146,7 +146,7 @@ func BenchmarkMountMapParallelLookup(b *testing.B) {
 				keys := make([]VirtualDentry, 0, numMounts)
 				for i := 0; i < numMounts; i++ {
 					mount := newBenchMount()
-					key := mount.loadKey()
+					key := mount.saveKey()
 					ms[key] = mount
 					keys = append(keys, key)
 				}
@@ -201,7 +201,7 @@ func BenchmarkMountSyncMapParallelLookup(b *testing.B) {
 				keys := make([]VirtualDentry, 0, numMounts)
 				for i := 0; i < numMounts; i++ {
 					mount := newBenchMount()
-					key := mount.loadKey()
+					key := mount.getKey()
 					ms.Store(key, mount)
 					keys = append(keys, key)
 				}
@@ -283,7 +283,7 @@ func BenchmarkMountMapNegativeLookup(b *testing.B) {
 			ms := make(map[VirtualDentry]*Mount)
 			for i := 0; i < numMounts; i++ {
 				mount := newBenchMount()
-				ms[mount.loadKey()] = mount
+				ms[mount.getKey()] = mount
 			}
 			negkeys := make([]VirtualDentry, 0, numMounts)
 			for i := 0; i < numMounts; i++ {
@@ -318,7 +318,7 @@ func BenchmarkMountSyncMapNegativeLookup(b *testing.B) {
 			var ms sync.Map
 			for i := 0; i < numMounts; i++ {
 				mount := newBenchMount()
-				ms.Store(mount.loadKey(), mount)
+				ms.Store(mount.saveKey(), mount)
 			}
 			negkeys := make([]VirtualDentry, 0, numMounts)
 			for i := 0; i < numMounts; i++ {
@@ -372,7 +372,7 @@ func BenchmarkMountMapInsert(b *testing.B) {
 	b.ResetTimer()
 	for i := range mounts {
 		mount := mounts[i]
-		ms[mount.loadKey()] = mount
+		ms[mount.saveKey()] = mount
 	}
 }
 
@@ -392,7 +392,7 @@ func BenchmarkMountSyncMapInsert(b *testing.B) {
 	b.ResetTimer()
 	for i := range mounts {
 		mount := mounts[i]
-		ms.Store(mount.loadKey(), mount)
+		ms.Store(mount.saveKey(), mount)
 	}
 }
 
@@ -425,13 +425,13 @@ func BenchmarkMountMapRemove(b *testing.B) {
 	ms := make(map[VirtualDentry]*Mount)
 	for i := range mounts {
 		mount := mounts[i]
-		ms[mount.loadKey()] = mount
+		ms[mount.saveKey()] = mount
 	}
 
 	b.ResetTimer()
 	for i := range mounts {
 		mount := mounts[i]
-		delete(ms, mount.loadKey())
+		delete(ms, mount.saveKey())
 	}
 }
 
@@ -447,12 +447,12 @@ func BenchmarkMountSyncMapRemove(b *testing.B) {
 	var ms sync.Map
 	for i := range mounts {
 		mount := mounts[i]
-		ms.Store(mount.loadKey(), mount)
+		ms.Store(mount.saveKey(), mount)
 	}
 
 	b.ResetTimer()
 	for i := range mounts {
 		mount := mounts[i]
-		ms.Delete(mount.loadKey())
+		ms.Delete(mount.saveKey())
 	}
 }

pkg/sentry/vfs/mount_unsafe.go

@@ -34,6 +34,8 @@ import (
 // structurally identical to VirtualDentry, but stores its fields as
 // unsafe.Pointer since mutators synchronize with VFS path traversal using
 // seqcounts.
+//
+// This is explicitly not savable.
 type mountKey struct {
 	parent unsafe.Pointer // *Mount
 	point  unsafe.Pointer // *Dentry
@@ -47,19 +49,23 @@ func (mnt *Mount) point() *Dentry {
 	return (*Dentry)(atomic.LoadPointer(&mnt.key.point))
 }
 
-func (mnt *Mount) loadKey() VirtualDentry {
+func (mnt *Mount) getKey() VirtualDentry {
 	return VirtualDentry{
 		mount:  mnt.parent(),
 		dentry: mnt.point(),
 	}
 }
 
+func (mnt *Mount) saveKey() VirtualDentry { return mnt.getKey() }
+
 // Invariant: mnt.key.parent == nil. vd.Ok().
-func (mnt *Mount) storeKey(vd VirtualDentry) {
+func (mnt *Mount) setKey(vd VirtualDentry) {
 	atomic.StorePointer(&mnt.key.parent, unsafe.Pointer(vd.mount))
 	atomic.StorePointer(&mnt.key.point, unsafe.Pointer(vd.dentry))
 }
 
+func (mnt *Mount) loadKey(vd VirtualDentry) { mnt.setKey(vd) }
+
 // mountTable maps (mount parent, mount point) pairs to mounts. It supports
 // efficient concurrent lookup, even in the presence of concurrent mutators
 // (provided mutation is sufficiently uncommon).
@@ -92,6 +98,7 @@ type mountTable struct {
 	// length and cap in separate uint32s) for ~free.
 	size uint64
 
+	// FIXME(gvisor.dev/issue/1663): Slots need to be saved.
 	slots unsafe.Pointer `state:"nosave"` // []mountSlot; never nil after Init
 }
 

pkg/sentry/vfs/options.go

@@ -21,6 +21,8 @@ import (
 
 // GetDentryOptions contains options to VirtualFilesystem.GetDentryAt() and
 // FilesystemImpl.GetDentryAt().
+//
+// +stateify savable
 type GetDentryOptions struct {
 	// If CheckSearchable is true, FilesystemImpl.GetDentryAt() must check that
 	// the returned Dentry is a directory for which creds has search
@@ -30,6 +32,8 @@ type GetDentryOptions struct {
 
 // MkdirOptions contains options to VirtualFilesystem.MkdirAt() and
 // FilesystemImpl.MkdirAt().
+//
+// +stateify savable
 type MkdirOptions struct {
 	// Mode is the file mode bits for the created directory.
 	Mode linux.FileMode
@@ -56,6 +60,8 @@ type MkdirOptions struct {
 
 // MknodOptions contains options to VirtualFilesystem.MknodAt() and
 // FilesystemImpl.MknodAt().
+//
+// +stateify savable
 type MknodOptions struct {
 	// Mode is the file type and mode bits for the created file.
 	Mode linux.FileMode
@@ -72,6 +78,8 @@ type MknodOptions struct {
 
 // MountFlags contains flags as specified for mount(2), e.g. MS_NOEXEC.
 // MS_RDONLY is not part of MountFlags because it's tracked in Mount.writers.
+//
+// +stateify savable
 type MountFlags struct {
 	// NoExec is equivalent to MS_NOEXEC.
 	NoExec bool
@@ -93,6 +101,8 @@ type MountFlags struct {
 }
 
 // MountOptions contains options to VirtualFilesystem.MountAt().
+//
+// +stateify savable
 type MountOptions struct {
 	// Flags contains flags as specified for mount(2), e.g. MS_NOEXEC.
 	Flags MountFlags
@@ -112,6 +122,8 @@ type MountOptions struct {
 
 // OpenOptions contains options to VirtualFilesystem.OpenAt() and
 // FilesystemImpl.OpenAt().
+//
+// +stateify savable
 type OpenOptions struct {
 	// Flags contains access mode and flags as specified for open(2).
 	//
@@ -137,6 +149,8 @@ type OpenOptions struct {
 // ReadOptions contains options to FileDescription.PRead(),
 // FileDescriptionImpl.PRead(), FileDescription.Read(), and
 // FileDescriptionImpl.Read().
+//
+// +stateify savable
 type ReadOptions struct {
 	// Flags contains flags as specified for preadv2(2).
 	Flags uint32
@@ -144,6 +158,8 @@ type ReadOptions struct {
 
 // RenameOptions contains options to VirtualFilesystem.RenameAt() and
 // FilesystemImpl.RenameAt().
+//
+// +stateify savable
 type RenameOptions struct {
 	// Flags contains flags as specified for renameat2(2).
 	Flags uint32
@@ -155,6 +171,8 @@ type RenameOptions struct {
 // SetStatOptions contains options to VirtualFilesystem.SetStatAt(),
 // FilesystemImpl.SetStatAt(), FileDescription.SetStat(), and
 // FileDescriptionImpl.SetStat().
+//
+// +stateify savable
 type SetStatOptions struct {
 	// Stat is the metadata that should be set. Only fields indicated by
 	// Stat.Mask should be set.
@@ -176,6 +194,8 @@ type SetStatOptions struct {
 
 // BoundEndpointOptions contains options to VirtualFilesystem.BoundEndpointAt()
 // and FilesystemImpl.BoundEndpointAt().
+//
+// +stateify savable
 type BoundEndpointOptions struct {
 	// Addr is the path of the file whose socket endpoint is being retrieved.
 	// It is generally irrelevant: most endpoints are stored at a dentry that
@@ -195,6 +215,8 @@ type BoundEndpointOptions struct {
 // GetXattrOptions contains options to VirtualFilesystem.GetXattrAt(),
 // FilesystemImpl.GetXattrAt(), FileDescription.GetXattr(), and
 // FileDescriptionImpl.GetXattr().
+//
+// +stateify savable
 type GetXattrOptions struct {
 	// Name is the name of the extended attribute to retrieve.
 	Name string
@@ -209,6 +231,8 @@ type GetXattrOptions struct {
 // SetXattrOptions contains options to VirtualFilesystem.SetXattrAt(),
 // FilesystemImpl.SetXattrAt(), FileDescription.SetXattr(), and
 // FileDescriptionImpl.SetXattr().
+//
+// +stateify savable
 type SetXattrOptions struct {
 	// Name is the name of the extended attribute being mutated.
 	Name string
@@ -223,6 +247,8 @@ type SetXattrOptions struct {
 // StatOptions contains options to VirtualFilesystem.StatAt(),
 // FilesystemImpl.StatAt(), FileDescription.Stat(), and
 // FileDescriptionImpl.Stat().
+//
+// +stateify savable
 type StatOptions struct {
 	// Mask is the set of fields in the returned Statx that the FilesystemImpl
 	// or FileDescriptionImpl should provide. Bits are as in linux.Statx.Mask.
@@ -240,6 +266,8 @@ type StatOptions struct {
 }
 
 // UmountOptions contains options to VirtualFilesystem.UmountAt().
+//
+// +stateify savable
 type UmountOptions struct {
 	// Flags contains flags as specified for umount2(2).
 	Flags uint32
@@ -248,6 +276,8 @@ type UmountOptions struct {
 // WriteOptions contains options to FileDescription.PWrite(),
 // FileDescriptionImpl.PWrite(), FileDescription.Write(), and
 // FileDescriptionImpl.Write().
+//
+// +stateify savable
 type WriteOptions struct {
 	// Flags contains flags as specified for pwritev2(2).
 	Flags uint32

pkg/sentry/vfs/permissions.go

@@ -26,6 +26,8 @@ import (
 )
 
 // AccessTypes is a bitmask of Unix file permissions.
+//
+// +stateify savable
 type AccessTypes uint16
 
 // Bits in AccessTypes.

pkg/sentry/vfs/resolving_path.go

@@ -35,6 +35,8 @@ import (
 // FilesystemImpl methods.
 //
 // ResolvingPath is loosely analogous to Linux's struct nameidata.
+//
+// +stateify savable
 type ResolvingPath struct {
 	vfs   *VirtualFilesystem
 	root  VirtualDentry // refs borrowed from PathOperation
@@ -88,6 +90,7 @@ func init() {
 // so error "constants" are really mutable vars, necessitating somewhat
 // expensive interface object comparisons.
 
+// +stateify savable
 type resolveMountRootOrJumpError struct{}
 
 // Error implements error.Error.
@@ -95,6 +98,7 @@ func (resolveMountRootOrJumpError) Error() string {
 	return "resolving mount root or jump"
 }
 
+// +stateify savable
 type resolveMountPointError struct{}
 
 // Error implements error.Error.
@@ -102,6 +106,7 @@ func (resolveMountPointError) Error() string {
 	return "resolving mount point"
 }
 
+// +stateify savable
 type resolveAbsSymlinkError struct{}
 
 // Error implements error.Error.

pkg/sentry/vfs/vfs.go

@@ -163,6 +163,8 @@ func (vfs *VirtualFilesystem) Init(ctx context.Context) error {
 // PathOperation is passed to VFS methods by pointer to reduce memory copying:
 // it's somewhat large and should never escape. (Options structs are passed by
 // pointer to VFS and FileDescription methods for the same reason.)
+//
+// +stateify savable
 type PathOperation struct {
 	// Root is the VFS root. References on Root are borrowed from the provider
 	// of the PathOperation.

pkg/state/types.go

@@ -107,6 +107,14 @@ func lookupNameFields(typ reflect.Type) (string, []string, bool) {
 		}
 		return name, nil, true
 	}
+	// Sanity check the type.
+	if raceEnabled {
+		if _, ok := reverseTypeDatabase[typ]; !ok {
+			// The type was not registered? Must be an embedded
+			// structure or something else.
+			return "", nil, false
+		}
+	}
 	// Extract the name from the object.
 	name := t.StateTypeName()
 	fields := t.StateFields()
@@ -313,6 +321,9 @@ var primitiveTypeDatabase = func() map[string]reflect.Type {
 // globalTypeDatabase is used for dispatching interfaces on decode.
 var globalTypeDatabase = map[string]reflect.Type{}
 
+// reverseTypeDatabase is a reverse mapping.
+var reverseTypeDatabase = map[reflect.Type]string{}
+
 // Register registers a type.
 //
 // This must be called on init and only done once.
@@ -358,4 +369,7 @@ func Register(t Type) {
 		Failf("conflicting name for %T: matches interfaceType", t)
 	}
 	globalTypeDatabase[name] = typ
+	if raceEnabled {
+		reverseTypeDatabase[typ] = name
+	}
 }