Merge pull request #3934 from avagin:feature/fuse

PiperOrigin-RevId: 332122081

1 files changed, 640 insertions, 70 deletions

diff --git a/pkg/abi/linux/fuse.go b/pkg/abi/linux/fuse.go
index 7e30483ee..d91c97a64 100644
--- a/pkg/abi/linux/fuse.go
+++ b/pkg/abi/linux/fuse.go
@@ -14,12 +14,20 @@
 
 package linux
 
+import (
+	"gvisor.dev/gvisor/pkg/marshal"
+	"gvisor.dev/gvisor/pkg/marshal/primitive"
+)
+
 // +marshal
 type FUSEOpcode uint32
 
 // +marshal
 type FUSEOpID uint64
 
+// FUSE_ROOT_ID is the id of root inode.
+const FUSE_ROOT_ID = 1
+
 // Opcodes for FUSE operations. Analogous to the opcodes in include/linux/fuse.h.
 const (
 	FUSE_LOOKUP   FUSEOpcode = 1
@@ -116,61 +124,28 @@ type FUSEHeaderOut struct {
 	Unique FUSEOpID
 }
 
-// FUSEWriteIn is the header written by a daemon when it makes a
-// write request to the FUSE filesystem.
-//
-// +marshal
-type FUSEWriteIn struct {
-	// Fh specifies the file handle that is being written to.
-	Fh uint64
-
-	// Offset is the offset of the write.
-	Offset uint64
-
-	// Size is the size of data being written.
-	Size uint32
-
-	// WriteFlags is the flags used during the write.
-	WriteFlags uint32
-
-	// LockOwner is the ID of the lock owner.
-	LockOwner uint64
-
-	// Flags is the flags for the request.
-	Flags uint32
-
-	_ uint32
-}
-
 // FUSE_INIT flags, consistent with the ones in include/uapi/linux/fuse.h.
+// Our taget version is 7.23 but we have few implemented in advance.
 const (
-	FUSE_ASYNC_READ          = 1 << 0
-	FUSE_POSIX_LOCKS         = 1 << 1
-	FUSE_FILE_OPS            = 1 << 2
-	FUSE_ATOMIC_O_TRUNC      = 1 << 3
-	FUSE_EXPORT_SUPPORT      = 1 << 4
-	FUSE_BIG_WRITES          = 1 << 5
-	FUSE_DONT_MASK           = 1 << 6
-	FUSE_SPLICE_WRITE        = 1 << 7
-	FUSE_SPLICE_MOVE         = 1 << 8
-	FUSE_SPLICE_READ         = 1 << 9
-	FUSE_FLOCK_LOCKS         = 1 << 10
-	FUSE_HAS_IOCTL_DIR       = 1 << 11
-	FUSE_AUTO_INVAL_DATA     = 1 << 12
-	FUSE_DO_READDIRPLUS      = 1 << 13
-	FUSE_READDIRPLUS_AUTO    = 1 << 14
-	FUSE_ASYNC_DIO           = 1 << 15
-	FUSE_WRITEBACK_CACHE     = 1 << 16
-	FUSE_NO_OPEN_SUPPORT     = 1 << 17
-	FUSE_PARALLEL_DIROPS     = 1 << 18
-	FUSE_HANDLE_KILLPRIV     = 1 << 19
-	FUSE_POSIX_ACL           = 1 << 20
-	FUSE_ABORT_ERROR         = 1 << 21
-	FUSE_MAX_PAGES           = 1 << 22
-	FUSE_CACHE_SYMLINKS      = 1 << 23
-	FUSE_NO_OPENDIR_SUPPORT  = 1 << 24
-	FUSE_EXPLICIT_INVAL_DATA = 1 << 25
-	FUSE_MAP_ALIGNMENT       = 1 << 26
+	FUSE_ASYNC_READ       = 1 << 0
+	FUSE_POSIX_LOCKS      = 1 << 1
+	FUSE_FILE_OPS         = 1 << 2
+	FUSE_ATOMIC_O_TRUNC   = 1 << 3
+	FUSE_EXPORT_SUPPORT   = 1 << 4
+	FUSE_BIG_WRITES       = 1 << 5
+	FUSE_DONT_MASK        = 1 << 6
+	FUSE_SPLICE_WRITE     = 1 << 7
+	FUSE_SPLICE_MOVE      = 1 << 8
+	FUSE_SPLICE_READ      = 1 << 9
+	FUSE_FLOCK_LOCKS      = 1 << 10
+	FUSE_HAS_IOCTL_DIR    = 1 << 11
+	FUSE_AUTO_INVAL_DATA  = 1 << 12
+	FUSE_DO_READDIRPLUS   = 1 << 13
+	FUSE_READDIRPLUS_AUTO = 1 << 14
+	FUSE_ASYNC_DIO        = 1 << 15
+	FUSE_WRITEBACK_CACHE  = 1 << 16
+	FUSE_NO_OPEN_SUPPORT  = 1 << 17
+	FUSE_MAX_PAGES        = 1 << 22 // From FUSE 7.28
 )
 
 // currently supported FUSE protocol version numbers.
@@ -179,6 +154,13 @@ const (
 	FUSE_KERNEL_MINOR_VERSION = 31
 )
 
+// Constants relevant to FUSE operations.
+const (
+	FUSE_NAME_MAX     = 1024
+	FUSE_PAGE_SIZE    = 4096
+	FUSE_DIRENT_ALIGN = 8
+)
+
 // FUSEInitIn is the request sent by the kernel to the daemon,
 // to negotiate the version and flags.
 //
@@ -199,7 +181,7 @@ type FUSEInitIn struct {
 }
 
 // FUSEInitOut is the reply sent by the daemon to the kernel
-// for FUSEInitIn.
+// for FUSEInitIn. We target FUSE 7.23; this struct supports 7.28.
 //
 // +marshal
 type FUSEInitOut struct {
@@ -240,13 +222,16 @@ type FUSEInitOut struct {
 	// if the value from daemon is too large.
 	MaxPages uint16
 
-	// MapAlignment is an unknown field and not used by this package at this moment.
-	// Use as a placeholder to be consistent with the FUSE protocol.
-	MapAlignment uint16
+	_ uint16
 
 	_ [8]uint32
 }
 
+// FUSE_GETATTR_FH is currently the only flag of FUSEGetAttrIn.GetAttrFlags.
+// If it is set, the file handle (FUSEGetAttrIn.Fh) is used to indicate the
+// object instead of the node id attribute in the request header.
+const FUSE_GETATTR_FH = (1 << 0)
+
 // FUSEGetAttrIn is the request sent by the kernel to the daemon,
 // to get the attribute of a inode.
 //
@@ -267,22 +252,52 @@ type FUSEGetAttrIn struct {
 //
 // +marshal
 type FUSEAttr struct {
-	Ino       uint64
-	Size      uint64
-	Blocks    uint64
-	Atime     uint64
-	Mtime     uint64
-	Ctime     uint64
+	// Ino is the inode number of this file.
+	Ino uint64
+
+	// Size is the size of this file.
+	Size uint64
+
+	// Blocks is the number of the 512B blocks allocated by this file.
+	Blocks uint64
+
+	// Atime is the time of last access.
+	Atime uint64
+
+	// Mtime is the time of last modification.
+	Mtime uint64
+
+	// Ctime is the time of last status change.
+	Ctime uint64
+
+	// AtimeNsec is the nano second part of Atime.
 	AtimeNsec uint32
+
+	// MtimeNsec is the nano second part of Mtime.
 	MtimeNsec uint32
+
+	// CtimeNsec is the nano second part of Ctime.
 	CtimeNsec uint32
-	Mode      uint32
-	Nlink     uint32
-	UID       uint32
-	GID       uint32
-	Rdev      uint32
-	BlkSize   uint32
-	_         uint32
+
+	// Mode contains the file type and mode.
+	Mode uint32
+
+	// Nlink is the number of the hard links.
+	Nlink uint32
+
+	// UID is user ID of the owner.
+	UID uint32
+
+	// GID is group ID of the owner.
+	GID uint32
+
+	// Rdev is the device ID if this is a special file.
+	Rdev uint32
+
+	// BlkSize is the block size for filesystem I/O.
+	BlkSize uint32
+
+	_ uint32
 }
 
 // FUSEGetAttrOut is the reply sent by the daemon to the kernel
@@ -301,3 +316,558 @@ type FUSEGetAttrOut struct {
 	// Attr contains the metadata returned from the FUSE server
 	Attr FUSEAttr
 }
+
+// FUSEEntryOut is the reply sent by the daemon to the kernel
+// for FUSE_MKNOD, FUSE_MKDIR, FUSE_SYMLINK, FUSE_LINK and
+// FUSE_LOOKUP.
+//
+// +marshal
+type FUSEEntryOut struct {
+	// NodeID is the ID for current inode.
+	NodeID uint64
+
+	// Generation is the generation number of inode.
+	// Used to identify an inode that have different ID at different time.
+	Generation uint64
+
+	// EntryValid indicates timeout for an entry.
+	EntryValid uint64
+
+	// AttrValid indicates timeout for an entry's attributes.
+	AttrValid uint64
+
+	// EntryValidNsec indicates timeout for an entry in nanosecond.
+	EntryValidNSec uint32
+
+	// AttrValidNsec indicates timeout for an entry's attributes in nanosecond.
+	AttrValidNSec uint32
+
+	// Attr contains the attributes of an entry.
+	Attr FUSEAttr
+}
+
+// FUSELookupIn is the request sent by the kernel to the daemon
+// to look up a file name.
+//
+// Dynamically-sized objects cannot be marshalled.
+type FUSELookupIn struct {
+	marshal.StubMarshallable
+
+	// Name is a file name to be looked up.
+	Name string
+}
+
+// MarshalBytes serializes r.name to the dst buffer.
+func (r *FUSELookupIn) MarshalBytes(buf []byte) {
+	copy(buf, r.Name)
+}
+
+// SizeBytes is the size of the memory representation of FUSELookupIn.
+// 1 extra byte for null-terminated string.
+func (r *FUSELookupIn) SizeBytes() int {
+	return len(r.Name) + 1
+}
+
+// MAX_NON_LFS indicates the maximum offset without large file support.
+const MAX_NON_LFS = ((1 << 31) - 1)
+
+// flags returned by OPEN request.
+const (
+	// FOPEN_DIRECT_IO indicates bypassing page cache for this opened file.
+	FOPEN_DIRECT_IO = 1 << 0
+	// FOPEN_KEEP_CACHE avoids invalidate of data cache on open.
+	FOPEN_KEEP_CACHE = 1 << 1
+	// FOPEN_NONSEEKABLE indicates the file cannot be seeked.
+	FOPEN_NONSEEKABLE = 1 << 2
+)
+
+// FUSEOpenIn is the request sent by the kernel to the daemon,
+// to negotiate flags and get file handle.
+//
+// +marshal
+type FUSEOpenIn struct {
+	// Flags of this open request.
+	Flags uint32
+
+	_ uint32
+}
+
+// FUSEOpenOut is the reply sent by the daemon to the kernel
+// for FUSEOpenIn.
+//
+// +marshal
+type FUSEOpenOut struct {
+	// Fh is the file handler for opened file.
+	Fh uint64
+
+	// OpenFlag for the opened file.
+	OpenFlag uint32
+
+	_ uint32
+}
+
+// FUSE_READ flags, consistent with the ones in include/uapi/linux/fuse.h.
+const (
+	FUSE_READ_LOCKOWNER = 1 << 1
+)
+
+// FUSEReadIn is the request sent by the kernel to the daemon
+// for FUSE_READ.
+//
+// +marshal
+type FUSEReadIn struct {
+	// Fh is the file handle in userspace.
+	Fh uint64
+
+	// Offset is the read offset.
+	Offset uint64
+
+	// Size is the number of bytes to read.
+	Size uint32
+
+	// ReadFlags for this FUSE_READ request.
+	// Currently only contains FUSE_READ_LOCKOWNER.
+	ReadFlags uint32
+
+	// LockOwner is the id of the lock owner if there is one.
+	LockOwner uint64
+
+	// Flags for the underlying file.
+	Flags uint32
+
+	_ uint32
+}
+
+// FUSEWriteIn is the first part of the payload of the
+// request sent by the kernel to the daemon
+// for FUSE_WRITE (struct for FUSE version >= 7.9).
+//
+// The second part of the payload is the
+// binary bytes of the data to be written.
+//
+// +marshal
+type FUSEWriteIn struct {
+	// Fh is the file handle in userspace.
+	Fh uint64
+
+	// Offset is the write offset.
+	Offset uint64
+
+	// Size is the number of bytes to write.
+	Size uint32
+
+	// ReadFlags for this FUSE_WRITE request.
+	WriteFlags uint32
+
+	// LockOwner is the id of the lock owner if there is one.
+	LockOwner uint64
+
+	// Flags for the underlying file.
+	Flags uint32
+
+	_ uint32
+}
+
+// FUSEWriteOut is the payload of the reply sent by the daemon to the kernel
+// for a FUSE_WRITE request.
+//
+// +marshal
+type FUSEWriteOut struct {
+	// Size is the number of bytes written.
+	Size uint32
+
+	_ uint32
+}
+
+// FUSEReleaseIn is the request sent by the kernel to the daemon
+// when there is no more reference to a file.
+//
+// +marshal
+type FUSEReleaseIn struct {
+	// Fh is the file handler for the file to be released.
+	Fh uint64
+
+	// Flags of the file.
+	Flags uint32
+
+	// ReleaseFlags of this release request.
+	ReleaseFlags uint32
+
+	// LockOwner is the id of the lock owner if there is one.
+	LockOwner uint64
+}
+
+// FUSECreateMeta contains all the static fields of FUSECreateIn,
+// which is used for FUSE_CREATE.
+//
+// +marshal
+type FUSECreateMeta struct {
+	// Flags of the creating file.
+	Flags uint32
+
+	// Mode is the mode of the creating file.
+	Mode uint32
+
+	// Umask is the current file mode creation mask.
+	Umask uint32
+	_     uint32
+}
+
+// FUSECreateIn contains all the arguments sent by the kernel to the daemon, to
+// atomically create and open a new regular file.
+//
+// Dynamically-sized objects cannot be marshalled.
+type FUSECreateIn struct {
+	marshal.StubMarshallable
+
+	// CreateMeta contains mode, rdev and umash field for FUSE_MKNODS.
+	CreateMeta FUSECreateMeta
+
+	// Name is the name of the node to create.
+	Name string
+}
+
+// MarshalBytes serializes r.CreateMeta and r.Name to the dst buffer.
+func (r *FUSECreateIn) MarshalBytes(buf []byte) {
+	r.CreateMeta.MarshalBytes(buf[:r.CreateMeta.SizeBytes()])
+	copy(buf[r.CreateMeta.SizeBytes():], r.Name)
+}
+
+// SizeBytes is the size of the memory representation of FUSECreateIn.
+// 1 extra byte for null-terminated string.
+func (r *FUSECreateIn) SizeBytes() int {
+	return r.CreateMeta.SizeBytes() + len(r.Name) + 1
+}
+
+// FUSEMknodMeta contains all the static fields of FUSEMknodIn,
+// which is used for FUSE_MKNOD.
+//
+// +marshal
+type FUSEMknodMeta struct {
+	// Mode of the inode to create.
+	Mode uint32
+
+	// Rdev encodes device major and minor information.
+	Rdev uint32
+
+	// Umask is the current file mode creation mask.
+	Umask uint32
+
+	_ uint32
+}
+
+// FUSEMknodIn contains all the arguments sent by the kernel
+// to the daemon, to create a new file node.
+//
+// Dynamically-sized objects cannot be marshalled.
+type FUSEMknodIn struct {
+	marshal.StubMarshallable
+
+	// MknodMeta contains mode, rdev and umash field for FUSE_MKNODS.
+	MknodMeta FUSEMknodMeta
+
+	// Name is the name of the node to create.
+	Name string
+}
+
+// MarshalBytes serializes r.MknodMeta and r.Name to the dst buffer.
+func (r *FUSEMknodIn) MarshalBytes(buf []byte) {
+	r.MknodMeta.MarshalBytes(buf[:r.MknodMeta.SizeBytes()])
+	copy(buf[r.MknodMeta.SizeBytes():], r.Name)
+}
+
+// SizeBytes is the size of the memory representation of FUSEMknodIn.
+// 1 extra byte for null-terminated string.
+func (r *FUSEMknodIn) SizeBytes() int {
+	return r.MknodMeta.SizeBytes() + len(r.Name) + 1
+}
+
+// FUSESymLinkIn is the request sent by the kernel to the daemon,
+// to create a symbolic link.
+//
+// Dynamically-sized objects cannot be marshalled.
+type FUSESymLinkIn struct {
+	marshal.StubMarshallable
+
+	// Name of symlink to create.
+	Name string
+
+	// Target of the symlink.
+	Target string
+}
+
+// MarshalBytes serializes r.Name and r.Target to the dst buffer.
+// Left null-termination at end of r.Name and r.Target.
+func (r *FUSESymLinkIn) MarshalBytes(buf []byte) {
+	copy(buf, r.Name)
+	copy(buf[len(r.Name)+1:], r.Target)
+}
+
+// SizeBytes is the size of the memory representation of FUSESymLinkIn.
+// 2 extra bytes for null-terminated string.
+func (r *FUSESymLinkIn) SizeBytes() int {
+	return len(r.Name) + len(r.Target) + 2
+}
+
+// FUSEEmptyIn is used by operations without request body.
+type FUSEEmptyIn struct{ marshal.StubMarshallable }
+
+// MarshalBytes do nothing for marshal.
+func (r *FUSEEmptyIn) MarshalBytes(buf []byte) {}
+
+// SizeBytes is 0 for empty request.
+func (r *FUSEEmptyIn) SizeBytes() int {
+	return 0
+}
+
+// FUSEMkdirMeta contains all the static fields of FUSEMkdirIn,
+// which is used for FUSE_MKDIR.
+//
+// +marshal
+type FUSEMkdirMeta struct {
+	// Mode of the directory of create.
+	Mode uint32
+
+	// Umask is the user file creation mask.
+	Umask uint32
+}
+
+// FUSEMkdirIn contains all the arguments sent by the kernel
+// to the daemon, to create a new directory.
+//
+// Dynamically-sized objects cannot be marshalled.
+type FUSEMkdirIn struct {
+	marshal.StubMarshallable
+
+	// MkdirMeta contains Mode and Umask of the directory to create.
+	MkdirMeta FUSEMkdirMeta
+
+	// Name of the directory to create.
+	Name string
+}
+
+// MarshalBytes serializes r.MkdirMeta and r.Name to the dst buffer.
+func (r *FUSEMkdirIn) MarshalBytes(buf []byte) {
+	r.MkdirMeta.MarshalBytes(buf[:r.MkdirMeta.SizeBytes()])
+	copy(buf[r.MkdirMeta.SizeBytes():], r.Name)
+}
+
+// SizeBytes is the size of the memory representation of FUSEMkdirIn.
+// 1 extra byte for null-terminated Name string.
+func (r *FUSEMkdirIn) SizeBytes() int {
+	return r.MkdirMeta.SizeBytes() + len(r.Name) + 1
+}
+
+// FUSERmDirIn is the request sent by the kernel to the daemon
+// when trying to remove a directory.
+//
+// Dynamically-sized objects cannot be marshalled.
+type FUSERmDirIn struct {
+	marshal.StubMarshallable
+
+	// Name is a directory name to be removed.
+	Name string
+}
+
+// MarshalBytes serializes r.name to the dst buffer.
+func (r *FUSERmDirIn) MarshalBytes(buf []byte) {
+	copy(buf, r.Name)
+}
+
+// SizeBytes is the size of the memory representation of FUSERmDirIn.
+func (r *FUSERmDirIn) SizeBytes() int {
+	return len(r.Name) + 1
+}
+
+// FUSEDirents is a list of Dirents received from the FUSE daemon server.
+// It is used for FUSE_READDIR.
+//
+// Dynamically-sized objects cannot be marshalled.
+type FUSEDirents struct {
+	marshal.StubMarshallable
+
+	Dirents []*FUSEDirent
+}
+
+// FUSEDirent is a Dirent received from the FUSE daemon server.
+// It is used for FUSE_READDIR.
+//
+// Dynamically-sized objects cannot be marshalled.
+type FUSEDirent struct {
+	marshal.StubMarshallable
+
+	// Meta contains all the static fields of FUSEDirent.
+	Meta FUSEDirentMeta
+
+	// Name is the filename of the dirent.
+	Name string
+}
+
+// FUSEDirentMeta contains all the static fields of FUSEDirent.
+// It is used for FUSE_READDIR.
+//
+// +marshal
+type FUSEDirentMeta struct {
+	// Inode of the dirent.
+	Ino uint64
+
+	// Offset of the dirent.
+	Off uint64
+
+	// NameLen is the length of the dirent name.
+	NameLen uint32
+
+	// Type of the dirent.
+	Type uint32
+}
+
+// SizeBytes is the size of the memory representation of FUSEDirents.
+func (r *FUSEDirents) SizeBytes() int {
+	var sizeBytes int
+	for _, dirent := range r.Dirents {
+		sizeBytes += dirent.SizeBytes()
+	}
+
+	return sizeBytes
+}
+
+// UnmarshalBytes deserializes FUSEDirents from the src buffer.
+func (r *FUSEDirents) UnmarshalBytes(src []byte) {
+	for {
+		if len(src) <= (*FUSEDirentMeta)(nil).SizeBytes() {
+			break
+		}
+
+		// Its unclear how many dirents there are in src. Each dirent is dynamically
+		// sized and so we can't make assumptions about how many dirents we can allocate.
+		if r.Dirents == nil {
+			r.Dirents = make([]*FUSEDirent, 0)
+		}
+
+		// We have to allocate a struct for each dirent - there must be a better way
+		// to do this. Linux allocates 1 page to store all the dirents and then
+		// simply reads them from the page.
+		var dirent FUSEDirent
+		dirent.UnmarshalBytes(src)
+		r.Dirents = append(r.Dirents, &dirent)
+
+		src = src[dirent.SizeBytes():]
+	}
+}
+
+// SizeBytes is the size of the memory representation of FUSEDirent.
+func (r *FUSEDirent) SizeBytes() int {
+	dataSize := r.Meta.SizeBytes() + len(r.Name)
+
+	// Each Dirent must be padded such that its size is a multiple
+	// of FUSE_DIRENT_ALIGN. Similar to the fuse dirent alignment
+	// in linux/fuse.h.
+	return (dataSize + (FUSE_DIRENT_ALIGN - 1)) & ^(FUSE_DIRENT_ALIGN - 1)
+}
+
+// UnmarshalBytes deserializes FUSEDirent from the src buffer.
+func (r *FUSEDirent) UnmarshalBytes(src []byte) {
+	r.Meta.UnmarshalBytes(src)
+	src = src[r.Meta.SizeBytes():]
+
+	if r.Meta.NameLen > FUSE_NAME_MAX {
+		// The name is too long and therefore invalid. We don't
+		// need to unmarshal the name since it'll be thrown away.
+		return
+	}
+
+	buf := make([]byte, r.Meta.NameLen)
+	name := primitive.ByteSlice(buf)
+	name.UnmarshalBytes(src[:r.Meta.NameLen])
+	r.Name = string(name)
+}
+
+// FATTR_* consts are the attribute flags defined in include/uapi/linux/fuse.h.
+// These should be or-ed together for setattr to know what has been changed.
+const (
+	FATTR_MODE      = (1 << 0)
+	FATTR_UID       = (1 << 1)
+	FATTR_GID       = (1 << 2)
+	FATTR_SIZE      = (1 << 3)
+	FATTR_ATIME     = (1 << 4)
+	FATTR_MTIME     = (1 << 5)
+	FATTR_FH        = (1 << 6)
+	FATTR_ATIME_NOW = (1 << 7)
+	FATTR_MTIME_NOW = (1 << 8)
+	FATTR_LOCKOWNER = (1 << 9)
+	FATTR_CTIME     = (1 << 10)
+)
+
+// FUSESetAttrIn is the request sent by the kernel to the daemon,
+// to set the attribute(s) of a file.
+//
+// +marshal
+type FUSESetAttrIn struct {
+	// Valid indicates which attributes are modified by this request.
+	Valid uint32
+
+	_ uint32
+
+	// Fh is used to identify the file if FATTR_FH is set in Valid.
+	Fh uint64
+
+	// Size is the size that the request wants to change to.
+	Size uint64
+
+	// LockOwner is the owner of the lock that the request wants to change to.
+	LockOwner uint64
+
+	// Atime is the access time that the request wants to change to.
+	Atime uint64
+
+	// Mtime is the modification time that the request wants to change to.
+	Mtime uint64
+
+	// Ctime is the status change time that the request wants to change to.
+	Ctime uint64
+
+	// AtimeNsec is the nano second part of Atime.
+	AtimeNsec uint32
+
+	// MtimeNsec is the nano second part of Mtime.
+	MtimeNsec uint32
+
+	// CtimeNsec is the nano second part of Ctime.
+	CtimeNsec uint32
+
+	// Mode is the file mode that the request wants to change to.
+	Mode uint32
+
+	_ uint32
+
+	// UID is the user ID of the owner that the request wants to change to.
+	UID uint32
+
+	// GID is the group ID of the owner that the request wants to change to.
+	GID uint32
+
+	_ uint32
+}
+
+// FUSEUnlinkIn is the request sent by the kernel to the daemon
+// when trying to unlink a node.
+//
+// Dynamically-sized objects cannot be marshalled.
+type FUSEUnlinkIn struct {
+	marshal.StubMarshallable
+
+	// Name of the node to unlink.
+	Name string
+}
+
+// MarshalBytes serializes r.name to the dst buffer, which should
+// have size len(r.Name) + 1 and last byte set to 0.
+func (r *FUSEUnlinkIn) MarshalBytes(buf []byte) {
+	copy(buf, r.Name)
+}
+
+// SizeBytes is the size of the memory representation of FUSEUnlinkIn.
+// 1 extra byte for null-terminated Name string.
+func (r *FUSEUnlinkIn) SizeBytes() int {
+	return len(r.Name) + 1
+}