Merge pull request #3934 from avagin:feature/fuse

PiperOrigin-RevId: 332122081

48 files changed, 6253 insertions, 892 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
+}
diff --git a/pkg/marshal/marshal_impl_util.go b/pkg/marshal/marshal_impl_util.go
index 69f33321e..ea75e09f2 100644
--- a/pkg/marshal/marshal_impl_util.go
+++ b/pkg/marshal/marshal_impl_util.go
@@ -44,7 +44,7 @@ func (StubMarshallable) MarshalBytes(dst []byte) {
 
 // UnmarshalBytes implements Marshallable.UnmarshalBytes.
 func (StubMarshallable) UnmarshalBytes(src []byte) {
-	panic("Please implement your own UnMarshalBytes function")
+	panic("Please implement your own UnmarshalBytes function")
 }
 
 // Packed implements Marshallable.Packed.
diff --git a/pkg/sentry/fs/g3doc/fuse.md b/pkg/sentry/fs/g3doc/fuse.md
index 2ca84dd74..eccb1fb2f 100644
--- a/pkg/sentry/fs/g3doc/fuse.md
+++ b/pkg/sentry/fs/g3doc/fuse.md
@@ -95,6 +95,52 @@ ops can be implemented in parallel.
 -   Implement the remaining FUSE ops and decide if we can omit rarely used
     operations like ioctl.
 
+### Design Details
+
+#### Lifecycle for a FUSE Request
+
+-   User invokes a syscall
+-   Sentry prepares corresponding request
+    -   If FUSE device is available
+        -   Write the request in binary
+    -   If FUSE device is full
+        -   Kernel task blocked until available
+-   Sentry notifies the readers of fuse device that it's ready for read
+-   FUSE daemon reads the request and processes it
+-   Sentry waits until a reply is written to the FUSE device
+    -   but returns directly for async requests
+-   FUSE daemon writes to the fuse device
+-   Sentry processes the reply
+    -   For sync requests, unblock blocked kernel task
+    -   For async requests, execute pre-specified callback if any
+-   Sentry returns the syscall to the user
+
+#### Channels and Queues for Requests in Different Stages
+
+`connection.initializedChan`
+
+-   a channel that the requests issued before connection initialization blocks
+    on.
+
+`fd.queue`
+
+-   a queue of requests that haven’t been read by the FUSE daemon yet.
+
+`fd.completions`
+
+-   a map of the requests that have been prepared but not yet received a
+    response, including the ones on the `fd.queue`.
+
+`fd.waitQueue`
+
+-   a queue of waiters that is waiting for the fuse device fd to be available,
+    such as the FUSE daemon.
+
+`fd.fullQueueCh`
+
+-   a channel that the kernel task will be blocked on when the fd is not
+    available.
+
 # Appendix
 
 ## FUSE Protocol
diff --git a/pkg/sentry/fsimpl/fuse/BUILD b/pkg/sentry/fsimpl/fuse/BUILD
index 999c16bfd..045d7ab08 100644
--- a/pkg/sentry/fsimpl/fuse/BUILD
+++ b/pkg/sentry/fsimpl/fuse/BUILD
@@ -30,12 +30,17 @@ go_library(
     name = "fuse",
     srcs = [
         "connection.go",
+        "connection_control.go",
         "dev.go",
+        "directory.go",
+        "file.go",
         "fusefs.go",
-        "init.go",
         "inode_refs.go",
+        "read_write.go",
         "register.go",
+        "regular_file.go",
         "request_list.go",
+        "request_response.go",
     ],
     visibility = ["//pkg/sentry:internal"],
     deps = [
@@ -44,6 +49,7 @@ go_library(
         "//pkg/log",
         "//pkg/marshal",
         "//pkg/refs",
+        "//pkg/safemem",
         "//pkg/sentry/fsimpl/devtmpfs",
         "//pkg/sentry/fsimpl/kernfs",
         "//pkg/sentry/kernel",
@@ -60,7 +66,11 @@ go_library(
 go_test(
     name = "fuse_test",
     size = "small",
-    srcs = ["dev_test.go"],
+    srcs = [
+        "connection_test.go",
+        "dev_test.go",
+        "utils_test.go",
+    ],
     library = ":fuse",
     deps = [
         "//pkg/abi/linux",
diff --git a/pkg/sentry/fsimpl/fuse/connection.go b/pkg/sentry/fsimpl/fuse/connection.go
index eb1d1a2b7..dbc5e1954 100644
--- a/pkg/sentry/fsimpl/fuse/connection.go
+++ b/pkg/sentry/fsimpl/fuse/connection.go
@@ -15,31 +15,17 @@
 package fuse
 
 import (
-	"errors"
-	"fmt"
 	"sync"
-	"sync/atomic"
-	"syscall"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/log"
-	"gvisor.dev/gvisor/pkg/marshal"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
-	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
 	"gvisor.dev/gvisor/pkg/syserror"
 	"gvisor.dev/gvisor/pkg/waiter"
 )
 
-// maxActiveRequestsDefault is the default setting controlling the upper bound
-// on the number of active requests at any given time.
-const maxActiveRequestsDefault = 10000
-
-// Ordinary requests have even IDs, while interrupts IDs are odd.
-// Used to increment the unique ID for each FUSE request.
-var reqIDStep uint64 = 2
-
 const (
 	// fuseDefaultMaxBackground is the default value for MaxBackground.
 	fuseDefaultMaxBackground = 12
@@ -52,43 +38,36 @@ const (
 	fuseDefaultMaxPagesPerReq = 32
 )
 
-// Request represents a FUSE operation request that hasn't been sent to the
-// server yet.
-//
-// +stateify savable
-type Request struct {
-	requestEntry
-
-	id   linux.FUSEOpID
-	hdr  *linux.FUSEHeaderIn
-	data []byte
-}
-
-// Response represents an actual response from the server, including the
-// response payload.
-//
-// +stateify savable
-type Response struct {
-	opcode linux.FUSEOpcode
-	hdr    linux.FUSEHeaderOut
-	data   []byte
-}
-
 // connection is the struct by which the sentry communicates with the FUSE server daemon.
+// Lock order:
+// - conn.fd.mu
+// - conn.mu
+// - conn.asyncMu
 type connection struct {
 	fd *DeviceFD
 
+	// mu protects access to struct memebers.
+	mu sync.Mutex
+
+	// attributeVersion is the version of connection's attributes.
+	attributeVersion uint64
+
+	// We target FUSE 7.23.
 	// The following FUSE_INIT flags are currently unsupported by this implementation:
-	// - FUSE_ATOMIC_O_TRUNC: requires open(..., O_TRUNC)
 	// - FUSE_EXPORT_SUPPORT
-	// - FUSE_HANDLE_KILLPRIV
 	// - FUSE_POSIX_LOCKS: requires POSIX locks
 	// - FUSE_FLOCK_LOCKS: requires POSIX locks
 	// - FUSE_AUTO_INVAL_DATA: requires page caching eviction
-	// - FUSE_EXPLICIT_INVAL_DATA: requires page caching eviction
 	// - FUSE_DO_READDIRPLUS/FUSE_READDIRPLUS_AUTO: requires FUSE_READDIRPLUS implementation
 	// - FUSE_ASYNC_DIO
-	// - FUSE_POSIX_ACL: affects defaultPermissions, posixACL, xattr handler
+	// - FUSE_PARALLEL_DIROPS (7.25)
+	// - FUSE_HANDLE_KILLPRIV (7.26)
+	// - FUSE_POSIX_ACL: affects defaultPermissions, posixACL, xattr handler (7.26)
+	// - FUSE_ABORT_ERROR (7.27)
+	// - FUSE_CACHE_SYMLINKS (7.28)
+	// - FUSE_NO_OPENDIR_SUPPORT (7.29)
+	// - FUSE_EXPLICIT_INVAL_DATA: requires page caching eviction (7.30)
+	// - FUSE_MAP_ALIGNMENT (7.31)
 
 	// initialized after receiving FUSE_INIT reply.
 	// Until it's set, suspend sending FUSE requests.
@@ -98,10 +77,6 @@ type connection struct {
 	// initializedChan is used to block requests before initialization.
 	initializedChan chan struct{}
 
-	// blocked when there are too many outstading backgrounds requests (NumBackground == MaxBackground).
-	// TODO(gvisor.dev/issue/3185): update the numBackground accordingly; use a channel to block.
-	blocked bool
-
 	// connected (connection established) when a new FUSE file system is created.
 	// Set to false when:
 	//   umount,
@@ -109,48 +84,55 @@ type connection struct {
 	//   device release.
 	connected bool
 
-	// aborted via sysfs.
-	// TODO(gvisor.dev/issue/3185): abort all queued requests.
-	aborted bool
-
 	// connInitError if FUSE_INIT encountered error (major version mismatch).
 	// Only set in INIT.
 	connInitError bool
 
 	// connInitSuccess if FUSE_INIT is successful.
 	// Only set in INIT.
-	// Used for destory.
+	// Used for destory (not yet implemented).
 	connInitSuccess bool
 
-	// TODO(gvisor.dev/issue/3185): All the queue logic are working in progress.
-
-	// NumberBackground is the number of requests in the background.
-	numBackground uint16
+	// aborted via sysfs, and will send ECONNABORTED to read after disconnection (instead of ENODEV).
+	// Set only if abortErr is true and via fuse control fs (not yet implemented).
+	// TODO(gvisor.dev/issue/3525): set this to true when user aborts.
+	aborted bool
 
-	// congestionThreshold for NumBackground.
-	// Negotiated in FUSE_INIT.
-	congestionThreshold uint16
+	// numWating is the number of requests waiting to be
+	// sent to FUSE device or being processed by FUSE daemon.
+	numWaiting uint32
 
-	// maxBackground is the maximum number of NumBackground.
-	// Block connection when it is reached.
-	// Negotiated in FUSE_INIT.
-	maxBackground uint16
+	// Terminology note:
+	//
+	// - `asyncNumMax` is the `MaxBackground` in the FUSE_INIT_IN struct.
+	//
+	// - `asyncCongestionThreshold` is the `CongestionThreshold` in the FUSE_INIT_IN struct.
+	//
+	// We call the "background" requests in unix term as async requests.
+	// The "async requests" in unix term is our async requests that expect a reply,
+	// i.e. `!request.noReply`
 
-	// numActiveBackground is the number of requests in background and has being marked as active.
-	numActiveBackground uint16
+	// asyncMu protects the async request fields.
+	asyncMu sync.Mutex
 
-	// numWating is the number of requests waiting for completion.
-	numWaiting uint32
+	// asyncNum is the number of async requests.
+	// Protected by asyncMu.
+	asyncNum uint16
 
-	// TODO(gvisor.dev/issue/3185): BgQueue
-	// some queue for background queued requests.
+	// asyncCongestionThreshold the number of async requests.
+	// Negotiated in FUSE_INIT as "CongestionThreshold".
+	// TODO(gvisor.dev/issue/3529): add congestion control.
+	// Protected by asyncMu.
+	asyncCongestionThreshold uint16
 
-	// bgLock protects:
-	// MaxBackground, CongestionThreshold, NumBackground,
-	// NumActiveBackground, BgQueue, Blocked.
-	bgLock sync.Mutex
+	// asyncNumMax is the maximum number of asyncNum.
+	// Connection blocks the async requests when it is reached.
+	// Negotiated in FUSE_INIT as "MaxBackground".
+	// Protected by asyncMu.
+	asyncNumMax uint16
 
 	// maxRead is the maximum size of a read buffer in in bytes.
+	// Initialized from a fuse fs parameter.
 	maxRead uint32
 
 	// maxWrite is the maximum size of a write buffer in bytes.
@@ -165,23 +147,20 @@ type connection struct {
 	// Negotiated and only set in INIT.
 	minor uint32
 
-	// asyncRead if read pages asynchronously.
+	// atomicOTrunc is true when FUSE does not send a separate SETATTR request
+	// before open with O_TRUNC flag.
 	// Negotiated and only set in INIT.
-	asyncRead bool
+	atomicOTrunc bool
 
-	// abortErr is true if kernel need to return an unique read error after abort.
+	// asyncRead if read pages asynchronously.
 	// Negotiated and only set in INIT.
-	abortErr bool
+	asyncRead bool
 
 	// writebackCache is true for write-back cache policy,
 	// false for write-through policy.
 	// Negotiated and only set in INIT.
 	writebackCache bool
 
-	// cacheSymlinks if filesystem needs to cache READLINK responses in page cache.
-	// Negotiated and only set in INIT.
-	cacheSymlinks bool
-
 	// bigWrites if doing multi-page cached writes.
 	// Negotiated and only set in INIT.
 	bigWrites bool
@@ -189,116 +168,70 @@ type connection struct {
 	// dontMask if filestestem does not apply umask to creation modes.
 	// Negotiated in INIT.
 	dontMask bool
+
+	// noOpen if FUSE server doesn't support open operation.
+	// This flag only influence performance, not correctness of the program.
+	noOpen bool
 }
 
 // newFUSEConnection creates a FUSE connection to fd.
-func newFUSEConnection(_ context.Context, fd *vfs.FileDescription, maxInFlightRequests uint64) (*connection, error) {
+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
 	// mount a FUSE filesystem.
 	fuseFD := fd.Impl().(*DeviceFD)
-	fuseFD.mounted = true
 
 	// Create the writeBuf for the header to be stored in.
 	hdrLen := uint32((*linux.FUSEHeaderOut)(nil).SizeBytes())
 	fuseFD.writeBuf = make([]byte, hdrLen)
 	fuseFD.completions = make(map[linux.FUSEOpID]*futureResponse)
-	fuseFD.fullQueueCh = make(chan struct{}, maxInFlightRequests)
+	fuseFD.fullQueueCh = make(chan struct{}, opts.maxActiveRequests)
 	fuseFD.writeCursor = 0
 
 	return &connection{
-		fd:                  fuseFD,
-		maxBackground:       fuseDefaultMaxBackground,
-		congestionThreshold: fuseDefaultCongestionThreshold,
-		maxPages:            fuseDefaultMaxPagesPerReq,
-		initializedChan:     make(chan struct{}),
-		connected:           true,
-	}, nil
-}
-
-// SetInitialized atomically sets the connection as initialized.
-func (conn *connection) SetInitialized() {
-	// Unblock the requests sent before INIT.
-	close(conn.initializedChan)
-
-	// Close the channel first to avoid the non-atomic situation
-	// where conn.initialized is true but there are
-	// tasks being blocked on the channel.
-	// And it prevents the newer tasks from gaining
-	// unnecessary higher chance to be issued before the blocked one.
-
-	atomic.StoreInt32(&(conn.initialized), int32(1))
-}
-
-// IsInitialized atomically check if the connection is initialized.
-// pairs with SetInitialized().
-func (conn *connection) Initialized() bool {
-	return atomic.LoadInt32(&(conn.initialized)) != 0
-}
-
-// NewRequest creates a new request that can be sent to the FUSE server.
-func (conn *connection) NewRequest(creds *auth.Credentials, pid uint32, ino uint64, opcode linux.FUSEOpcode, payload marshal.Marshallable) (*Request, error) {
-	conn.fd.mu.Lock()
-	defer conn.fd.mu.Unlock()
-	conn.fd.nextOpID += linux.FUSEOpID(reqIDStep)
-
-	hdrLen := (*linux.FUSEHeaderIn)(nil).SizeBytes()
-	hdr := linux.FUSEHeaderIn{
-		Len:    uint32(hdrLen + payload.SizeBytes()),
-		Opcode: opcode,
-		Unique: conn.fd.nextOpID,
-		NodeID: ino,
-		UID:    uint32(creds.EffectiveKUID),
-		GID:    uint32(creds.EffectiveKGID),
-		PID:    pid,
-	}
-
-	buf := make([]byte, hdr.Len)
-	hdr.MarshalUnsafe(buf[:hdrLen])
-	payload.MarshalUnsafe(buf[hdrLen:])
-
-	return &Request{
-		id:   hdr.Unique,
-		hdr:  &hdr,
-		data: buf,
+		fd:                       fuseFD,
+		asyncNumMax:              fuseDefaultMaxBackground,
+		asyncCongestionThreshold: fuseDefaultCongestionThreshold,
+		maxRead:                  opts.maxRead,
+		maxPages:                 fuseDefaultMaxPagesPerReq,
+		initializedChan:          make(chan struct{}),
+		connected:                true,
 	}, nil
 }
 
-// Call makes a request to the server and blocks the invoking task until a
-// server responds with a response. Task should never be nil.
-// Requests will not be sent before the connection is initialized.
-// For async tasks, use CallAsync().
-func (conn *connection) Call(t *kernel.Task, r *Request) (*Response, error) {
-	// Block requests sent before connection is initalized.
-	if !conn.Initialized() {
-		if err := t.Block(conn.initializedChan); err != nil {
-			return nil, err
-		}
-	}
-
-	return conn.call(t, r)
+// CallAsync makes an async (aka background) request.
+// It's a simple wrapper around Call().
+func (conn *connection) CallAsync(t *kernel.Task, r *Request) error {
+	r.async = true
+	_, err := conn.Call(t, r)
+	return err
 }
 
-// CallAsync makes an async (aka background) request.
-// Those requests either do not expect a response (e.g. release) or
-// the response should be handled by others (e.g. init).
-// Return immediately unless the connection is blocked (before initialization).
-// Async call example: init, release, forget, aio, interrupt.
+// Call makes a request to the server.
+// Block before the connection is initialized.
 // When the Request is FUSE_INIT, it will not be blocked before initialization.
-func (conn *connection) CallAsync(t *kernel.Task, r *Request) error {
+// Task should never be nil.
+//
+// For a sync request, it blocks the invoking task until
+// a server responds with a response.
+//
+// For an async request (that do not expect a response immediately),
+// it returns directly unless being blocked either before initialization
+// or when there are too many async requests ongoing.
+//
+// Example for async request:
+// init, readahead, write, async read/write, fuse_notify_reply,
+// non-sync release, interrupt, forget.
+//
+// The forget request does not have a reply,
+// as documented in include/uapi/linux/fuse.h:FUSE_FORGET.
+func (conn *connection) Call(t *kernel.Task, r *Request) (*Response, error) {
 	// Block requests sent before connection is initalized.
 	if !conn.Initialized() && r.hdr.Opcode != linux.FUSE_INIT {
 		if err := t.Block(conn.initializedChan); err != nil {
-			return err
+			return nil, err
 		}
 	}
 
-	// This should be the only place that invokes call() with a nil task.
-	_, err := conn.call(nil, r)
-	return err
-}
-
-// call makes a call without blocking checks.
-func (conn *connection) call(t *kernel.Task, r *Request) (*Response, error) {
 	if !conn.connected {
 		return nil, syserror.ENOTCONN
 	}
@@ -315,31 +248,6 @@ func (conn *connection) call(t *kernel.Task, r *Request) (*Response, error) {
 	return fut.resolve(t)
 }
 
-// Error returns the error of the FUSE call.
-func (r *Response) Error() error {
-	errno := r.hdr.Error
-	if errno >= 0 {
-		return nil
-	}
-
-	sysErrNo := syscall.Errno(-errno)
-	return error(sysErrNo)
-}
-
-// UnmarshalPayload unmarshals the response data into m.
-func (r *Response) UnmarshalPayload(m marshal.Marshallable) error {
-	hdrLen := r.hdr.SizeBytes()
-	haveDataLen := r.hdr.Len - uint32(hdrLen)
-	wantDataLen := uint32(m.SizeBytes())
-
-	if haveDataLen < wantDataLen {
-		return fmt.Errorf("payload too small. Minimum data lenth required: %d,  but got data length %d", wantDataLen, haveDataLen)
-	}
-
-	m.UnmarshalUnsafe(r.data[hdrLen:])
-	return nil
-}
-
 // callFuture makes a request to the server and returns a future response.
 // Call resolve() when the response needs to be fulfilled.
 func (conn *connection) callFuture(t *kernel.Task, r *Request) (*futureResponse, error) {
@@ -358,11 +266,6 @@ func (conn *connection) callFuture(t *kernel.Task, r *Request) (*futureResponse,
 	// if there are always too many ongoing requests all the time. The
 	// supported maxActiveRequests setting should be really high to avoid this.
 	for conn.fd.numActiveRequests == conn.fd.fs.opts.maxActiveRequests {
-		if t == nil {
-			// Since there is no task that is waiting. We must error out.
-			return nil, errors.New("FUSE request queue full")
-		}
-
 		log.Infof("Blocking request %v from being queued. Too many active requests: %v",
 			r.id, conn.fd.numActiveRequests)
 		conn.fd.mu.Unlock()
@@ -378,9 +281,19 @@ func (conn *connection) callFuture(t *kernel.Task, r *Request) (*futureResponse,
 
 // callFutureLocked makes a request to the server and returns a future response.
 func (conn *connection) callFutureLocked(t *kernel.Task, r *Request) (*futureResponse, error) {
+	// Check connected again holding conn.mu.
+	conn.mu.Lock()
+	if !conn.connected {
+		conn.mu.Unlock()
+		// we checked connected before,
+		// this must be due to aborted connection.
+		return nil, syserror.ECONNABORTED
+	}
+	conn.mu.Unlock()
+
 	conn.fd.queue.PushBack(r)
-	conn.fd.numActiveRequests += 1
-	fut := newFutureResponse(r.hdr.Opcode)
+	conn.fd.numActiveRequests++
+	fut := newFutureResponse(r)
 	conn.fd.completions[r.id] = fut
 
 	// Signal the readers that there is something to read.
@@ -388,50 +301,3 @@ func (conn *connection) callFutureLocked(t *kernel.Task, r *Request) (*futureRes
 
 	return fut, nil
 }
-
-// futureResponse represents an in-flight request, that may or may not have
-// completed yet. Convert it to a resolved Response by calling Resolve, but note
-// that this may block.
-//
-// +stateify savable
-type futureResponse struct {
-	opcode linux.FUSEOpcode
-	ch     chan struct{}
-	hdr    *linux.FUSEHeaderOut
-	data   []byte
-}
-
-// newFutureResponse creates a future response to a FUSE request.
-func newFutureResponse(opcode linux.FUSEOpcode) *futureResponse {
-	return &futureResponse{
-		opcode: opcode,
-		ch:     make(chan struct{}),
-	}
-}
-
-// resolve blocks the task until the server responds to its corresponding request,
-// then returns a resolved response.
-func (f *futureResponse) resolve(t *kernel.Task) (*Response, error) {
-	// If there is no Task associated with this request  - then we don't try to resolve
-	// the response.  Instead, the task writing the response (proxy to the server) will
-	// process the response on our behalf.
-	if t == nil {
-		log.Infof("fuse.Response.resolve: Not waiting on a response from server.")
-		return nil, nil
-	}
-
-	if err := t.Block(f.ch); err != nil {
-		return nil, err
-	}
-
-	return f.getResponse(), nil
-}
-
-// getResponse creates a Response from the data the futureResponse has.
-func (f *futureResponse) getResponse() *Response {
-	return &Response{
-		opcode: f.opcode,
-		hdr:    *f.hdr,
-		data:   f.data,
-	}
-}
diff --git a/pkg/sentry/fsimpl/fuse/init.go b/pkg/sentry/fsimpl/fuse/connection_control.go
index 779c2bd3f..bfde78559 100644
--- a/pkg/sentry/fsimpl/fuse/init.go
+++ b/pkg/sentry/fsimpl/fuse/connection_control.go
@@ -15,7 +15,11 @@
 package fuse
 
 import (
+	"sync/atomic"
+	"syscall"
+
 	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 )
 
@@ -29,9 +33,10 @@ const (
 	// Follow the same behavior as unix fuse implementation.
 	fuseMaxTimeGranNs = 1000000000
 
-	// Minimum value for MaxWrite.
+	// Minimum value for MaxWrite and MaxRead.
 	// Follow the same behavior as unix fuse implementation.
 	fuseMinMaxWrite = 4096
+	fuseMinMaxRead  = 4096
 
 	// Temporary default value for max readahead, 128kb.
 	fuseDefaultMaxReadahead = 131072
@@ -49,6 +54,26 @@ var (
 	MaxUserCongestionThreshold uint16 = fuseDefaultCongestionThreshold
 )
 
+// SetInitialized atomically sets the connection as initialized.
+func (conn *connection) SetInitialized() {
+	// Unblock the requests sent before INIT.
+	close(conn.initializedChan)
+
+	// Close the channel first to avoid the non-atomic situation
+	// where conn.initialized is true but there are
+	// tasks being blocked on the channel.
+	// And it prevents the newer tasks from gaining
+	// unnecessary higher chance to be issued before the blocked one.
+
+	atomic.StoreInt32(&(conn.initialized), int32(1))
+}
+
+// IsInitialized atomically check if the connection is initialized.
+// pairs with SetInitialized().
+func (conn *connection) Initialized() bool {
+	return atomic.LoadInt32(&(conn.initialized)) != 0
+}
+
 // InitSend sends a FUSE_INIT request.
 func (conn *connection) InitSend(creds *auth.Credentials, pid uint32) error {
 	in := linux.FUSEInitIn{
@@ -70,29 +95,31 @@ func (conn *connection) InitSend(creds *auth.Credentials, pid uint32) error {
 }
 
 // InitRecv receives a FUSE_INIT reply and process it.
+//
+// Preconditions: conn.asyncMu must not be held if minor verion is newer than 13.
 func (conn *connection) InitRecv(res *Response, hasSysAdminCap bool) error {
 	if err := res.Error(); err != nil {
 		return err
 	}
 
-	var out linux.FUSEInitOut
-	if err := res.UnmarshalPayload(&out); err != nil {
+	initRes := fuseInitRes{initLen: res.DataLen()}
+	if err := res.UnmarshalPayload(&initRes); err != nil {
 		return err
 	}
 
-	return conn.initProcessReply(&out, hasSysAdminCap)
+	return conn.initProcessReply(&initRes.initOut, hasSysAdminCap)
 }
 
 // Process the FUSE_INIT reply from the FUSE server.
+// It tries to acquire the conn.asyncMu lock if minor version is newer than 13.
 func (conn *connection) initProcessReply(out *linux.FUSEInitOut, hasSysAdminCap bool) error {
+	// No matter error or not, always set initialzied.
+	// to unblock the blocked requests.
+	defer conn.SetInitialized()
+
 	// No support for old major fuse versions.
 	if out.Major != linux.FUSE_KERNEL_VERSION {
 		conn.connInitError = true
-
-		// Set the connection as initialized and unblock the blocked requests
-		// (i.e. return error for them).
-		conn.SetInitialized()
-
 		return nil
 	}
 
@@ -100,29 +127,14 @@ func (conn *connection) initProcessReply(out *linux.FUSEInitOut, hasSysAdminCap
 	conn.connInitSuccess = true
 	conn.minor = out.Minor
 
-	// No support for limits before minor version 13.
-	if out.Minor >= 13 {
-		conn.bgLock.Lock()
-
-		if out.MaxBackground > 0 {
-			conn.maxBackground = out.MaxBackground
-
-			if !hasSysAdminCap &&
-				conn.maxBackground > MaxUserBackgroundRequest {
-				conn.maxBackground = MaxUserBackgroundRequest
-			}
-		}
-
-		if out.CongestionThreshold > 0 {
-			conn.congestionThreshold = out.CongestionThreshold
-
-			if !hasSysAdminCap &&
-				conn.congestionThreshold > MaxUserCongestionThreshold {
-				conn.congestionThreshold = MaxUserCongestionThreshold
-			}
-		}
-
-		conn.bgLock.Unlock()
+	// No support for negotiating MaxWrite before minor version 5.
+	if out.Minor >= 5 {
+		conn.maxWrite = out.MaxWrite
+	} else {
+		conn.maxWrite = fuseMinMaxWrite
+	}
+	if conn.maxWrite < fuseMinMaxWrite {
+		conn.maxWrite = fuseMinMaxWrite
 	}
 
 	// No support for the following flags before minor version 6.
@@ -131,8 +143,6 @@ func (conn *connection) initProcessReply(out *linux.FUSEInitOut, hasSysAdminCap
 		conn.bigWrites = out.Flags&linux.FUSE_BIG_WRITES != 0
 		conn.dontMask = out.Flags&linux.FUSE_DONT_MASK != 0
 		conn.writebackCache = out.Flags&linux.FUSE_WRITEBACK_CACHE != 0
-		conn.cacheSymlinks = out.Flags&linux.FUSE_CACHE_SYMLINKS != 0
-		conn.abortErr = out.Flags&linux.FUSE_ABORT_ERROR != 0
 
 		// TODO(gvisor.dev/issue/3195): figure out how to use TimeGran (0 < TimeGran <= fuseMaxTimeGranNs).
 
@@ -148,19 +158,90 @@ func (conn *connection) initProcessReply(out *linux.FUSEInitOut, hasSysAdminCap
 		}
 	}
 
-	// No support for negotiating MaxWrite before minor version 5.
-	if out.Minor >= 5 {
-		conn.maxWrite = out.MaxWrite
-	} else {
-		conn.maxWrite = fuseMinMaxWrite
+	// No support for limits before minor version 13.
+	if out.Minor >= 13 {
+		conn.asyncMu.Lock()
+
+		if out.MaxBackground > 0 {
+			conn.asyncNumMax = out.MaxBackground
+
+			if !hasSysAdminCap &&
+				conn.asyncNumMax > MaxUserBackgroundRequest {
+				conn.asyncNumMax = MaxUserBackgroundRequest
+			}
+		}
+
+		if out.CongestionThreshold > 0 {
+			conn.asyncCongestionThreshold = out.CongestionThreshold
+
+			if !hasSysAdminCap &&
+				conn.asyncCongestionThreshold > MaxUserCongestionThreshold {
+				conn.asyncCongestionThreshold = MaxUserCongestionThreshold
+			}
+		}
+
+		conn.asyncMu.Unlock()
 	}
-	if conn.maxWrite < fuseMinMaxWrite {
-		conn.maxWrite = fuseMinMaxWrite
+
+	return nil
+}
+
+// Abort this FUSE connection.
+// It tries to acquire conn.fd.mu, conn.lock, conn.bgLock in order.
+// All possible requests waiting or blocking will be aborted.
+//
+// Preconditions: conn.fd.mu is locked.
+func (conn *connection) Abort(ctx context.Context) {
+	conn.mu.Lock()
+	conn.asyncMu.Lock()
+
+	if !conn.connected {
+		conn.asyncMu.Unlock()
+		conn.mu.Unlock()
+		conn.fd.mu.Unlock()
+		return
 	}
 
-	// Set connection as initialized and unblock the requests
-	// issued before init.
-	conn.SetInitialized()
+	conn.connected = false
 
-	return nil
+	// Empty the `fd.queue` that holds the requests
+	// not yet read by the FUSE daemon yet.
+	// These are a subset of the requests in `fuse.completion` map.
+	for !conn.fd.queue.Empty() {
+		req := conn.fd.queue.Front()
+		conn.fd.queue.Remove(req)
+	}
+
+	var terminate []linux.FUSEOpID
+
+	// 2. Collect the requests have not been sent to FUSE daemon,
+	// or have not received a reply.
+	for unique := range conn.fd.completions {
+		terminate = append(terminate, unique)
+	}
+
+	// Release locks to avoid deadlock.
+	conn.asyncMu.Unlock()
+	conn.mu.Unlock()
+
+	// 1. The requets blocked before initialization.
+	// Will reach call() `connected` check and return.
+	if !conn.Initialized() {
+		conn.SetInitialized()
+	}
+
+	// 2. Terminate the requests collected above.
+	// Set ECONNABORTED error.
+	// sendError() will remove them from `fd.completion` map.
+	// Will enter the path of a normally received error.
+	for _, toTerminate := range terminate {
+		conn.fd.sendError(ctx, -int32(syscall.ECONNABORTED), toTerminate)
+	}
+
+	// 3. The requests not yet written to FUSE device.
+	// Early terminate.
+	// Will reach callFutureLocked() `connected` check and return.
+	close(conn.fd.fullQueueCh)
+
+	// TODO(gvisor.dev/issue/3528): Forget all pending forget reqs.
 }
diff --git a/pkg/sentry/fsimpl/fuse/connection_test.go b/pkg/sentry/fsimpl/fuse/connection_test.go
new file mode 100644
index 000000000..91d16c1cf
--- /dev/null
+++ b/pkg/sentry/fsimpl/fuse/connection_test.go
@@ -0,0 +1,117 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package fuse
+
+import (
+	"math/rand"
+	"syscall"
+	"testing"
+
+	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/syserror"
+)
+
+// TestConnectionInitBlock tests if initialization
+// correctly blocks and unblocks the connection.
+// Since it's unfeasible to test kernelTask.Block() in unit test,
+// the code in Call() are not tested here.
+func TestConnectionInitBlock(t *testing.T) {
+	s := setup(t)
+	defer s.Destroy()
+
+	k := kernel.KernelFromContext(s.Ctx)
+
+	conn, _, err := newTestConnection(s, k, maxActiveRequestsDefault)
+	if err != nil {
+		t.Fatalf("newTestConnection: %v", err)
+	}
+
+	select {
+	case <-conn.initializedChan:
+		t.Fatalf("initializedChan should be blocking before SetInitialized")
+	default:
+	}
+
+	conn.SetInitialized()
+
+	select {
+	case <-conn.initializedChan:
+	default:
+		t.Fatalf("initializedChan should not be blocking after SetInitialized")
+	}
+}
+
+func TestConnectionAbort(t *testing.T) {
+	s := setup(t)
+	defer s.Destroy()
+
+	k := kernel.KernelFromContext(s.Ctx)
+	creds := auth.CredentialsFromContext(s.Ctx)
+	task := kernel.TaskFromContext(s.Ctx)
+
+	const numRequests uint64 = 256
+
+	conn, _, err := newTestConnection(s, k, numRequests)
+	if err != nil {
+		t.Fatalf("newTestConnection: %v", err)
+	}
+
+	testObj := &testPayload{
+		data: rand.Uint32(),
+	}
+
+	var futNormal []*futureResponse
+
+	for i := 0; i < int(numRequests); i++ {
+		req, err := conn.NewRequest(creds, uint32(i), uint64(i), 0, testObj)
+		if err != nil {
+			t.Fatalf("NewRequest creation failed: %v", err)
+		}
+		fut, err := conn.callFutureLocked(task, req)
+		if err != nil {
+			t.Fatalf("callFutureLocked failed: %v", err)
+		}
+		futNormal = append(futNormal, fut)
+	}
+
+	conn.Abort(s.Ctx)
+
+	// Abort should unblock the initialization channel.
+	// Note: no test requests are actually blocked on `conn.initializedChan`.
+	select {
+	case <-conn.initializedChan:
+	default:
+		t.Fatalf("initializedChan should not be blocking after SetInitialized")
+	}
+
+	// Abort will return ECONNABORTED error to unblocked requests.
+	for _, fut := range futNormal {
+		if fut.getResponse().hdr.Error != -int32(syscall.ECONNABORTED) {
+			t.Fatalf("Incorrect error code received for aborted connection: %v", fut.getResponse().hdr.Error)
+		}
+	}
+
+	// After abort, Call() should return directly with ENOTCONN.
+	req, err := conn.NewRequest(creds, 0, 0, 0, testObj)
+	if err != nil {
+		t.Fatalf("NewRequest creation failed: %v", err)
+	}
+	_, err = conn.Call(task, req)
+	if err != syserror.ENOTCONN {
+		t.Fatalf("Incorrect error code received for Call() after connection aborted")
+	}
+
+}
diff --git a/pkg/sentry/fsimpl/fuse/dev.go b/pkg/sentry/fsimpl/fuse/dev.go
index e522ff9a0..5539466ff 100644
--- a/pkg/sentry/fsimpl/fuse/dev.go
+++ b/pkg/sentry/fsimpl/fuse/dev.go
@@ -19,7 +19,6 @@ import (
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
-	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
@@ -56,9 +55,6 @@ type DeviceFD struct {
 	vfs.DentryMetadataFileDescriptionImpl
 	vfs.NoLockFD
 
-	// mounted specifies whether a FUSE filesystem was mounted using the DeviceFD.
-	mounted bool
-
 	// nextOpID is used to create new requests.
 	nextOpID linux.FUSEOpID
 
@@ -100,13 +96,15 @@ type DeviceFD struct {
 
 // Release implements vfs.FileDescriptionImpl.Release.
 func (fd *DeviceFD) Release(context.Context) {
-	fd.fs.conn.connected = false
+	if fd.fs != nil {
+		fd.fs.conn.connected = false
+	}
 }
 
 // PRead implements vfs.FileDescriptionImpl.PRead.
 func (fd *DeviceFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
 	// Operations on /dev/fuse don't make sense until a FUSE filesystem is mounted.
-	if !fd.mounted {
+	if fd.fs == nil {
 		return 0, syserror.EPERM
 	}
 
@@ -116,10 +114,16 @@ func (fd *DeviceFD) PRead(ctx context.Context, dst usermem.IOSequence, offset in
 // Read implements vfs.FileDescriptionImpl.Read.
 func (fd *DeviceFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
 	// Operations on /dev/fuse don't make sense until a FUSE filesystem is mounted.
-	if !fd.mounted {
+	if fd.fs == nil {
 		return 0, syserror.EPERM
 	}
 
+	// Return ENODEV if the filesystem is umounted.
+	if fd.fs.umounted {
+		// TODO(gvisor.dev/issue/3525): return ECONNABORTED if aborted via fuse control fs.
+		return 0, syserror.ENODEV
+	}
+
 	// We require that any Read done on this filesystem have a sane minimum
 	// read buffer. It must have the capacity for the fixed parts of any request
 	// header (Linux uses the request header and the FUSEWriteIn header for this
@@ -143,58 +147,82 @@ func (fd *DeviceFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.R
 }
 
 // readLocked implements the reading of the fuse device while locked with DeviceFD.mu.
+//
+// Preconditions: dst is large enough for any reasonable request.
 func (fd *DeviceFD) readLocked(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
-	if fd.queue.Empty() {
-		return 0, syserror.ErrWouldBlock
-	}
+	var req *Request
 
-	var readCursor uint32
-	var bytesRead int64
-	for {
-		req := fd.queue.Front()
-		if dst.NumBytes() < int64(req.hdr.Len) {
-			// The request is too large. Cannot process it. All requests must be smaller than the
-			// negotiated size as specified by Connection.MaxWrite set as part of the FUSE_INIT
-			// handshake.
-			errno := -int32(syscall.EIO)
-			if req.hdr.Opcode == linux.FUSE_SETXATTR {
-				errno = -int32(syscall.E2BIG)
-			}
+	// Find the first valid request.
+	// For the normal case this loop only execute once.
+	for !fd.queue.Empty() {
+		req = fd.queue.Front()
 
-			// Return the error to the calling task.
-			if err := fd.sendError(ctx, errno, req); err != nil {
-				return 0, err
-			}
+		if int64(req.hdr.Len)+int64(len(req.payload)) <= dst.NumBytes() {
+			break
+		}
 
-			// We're done with this request.
-			fd.queue.Remove(req)
+		// The request is too large. Cannot process it. All requests must be smaller than the
+		// negotiated size as specified by Connection.MaxWrite set as part of the FUSE_INIT
+		// handshake.
+		errno := -int32(syscall.EIO)
+		if req.hdr.Opcode == linux.FUSE_SETXATTR {
+			errno = -int32(syscall.E2BIG)
+		}
 
-			// Restart the read as this request was invalid.
-			log.Warningf("fuse.DeviceFD.Read: request found was too large. Restarting read.")
-			return fd.readLocked(ctx, dst, opts)
+		// Return the error to the calling task.
+		if err := fd.sendError(ctx, errno, req.hdr.Unique); err != nil {
+			return 0, err
 		}
 
-		n, err := dst.CopyOut(ctx, req.data[readCursor:])
+		// We're done with this request.
+		fd.queue.Remove(req)
+		req = nil
+	}
+
+	if req == nil {
+		return 0, syserror.ErrWouldBlock
+	}
+
+	// We already checked the size: dst must be able to fit the whole request.
+	// Now we write the marshalled header, the payload,
+	// and the potential additional payload
+	// to the user memory IOSequence.
+
+	n, err := dst.CopyOut(ctx, req.data)
+	if err != nil {
+		return 0, err
+	}
+	if n != len(req.data) {
+		return 0, syserror.EIO
+	}
+
+	if req.hdr.Opcode == linux.FUSE_WRITE {
+		written, err := dst.DropFirst(n).CopyOut(ctx, req.payload)
 		if err != nil {
 			return 0, err
 		}
-		readCursor += uint32(n)
-		bytesRead += int64(n)
-
-		if readCursor >= req.hdr.Len {
-			// Fully done with this req, remove it from the queue.
-			fd.queue.Remove(req)
-			break
+		if written != len(req.payload) {
+			return 0, syserror.EIO
 		}
+		n += int(written)
+	}
+
+	// Fully done with this req, remove it from the queue.
+	fd.queue.Remove(req)
+
+	// Remove noReply ones from map of requests expecting a reply.
+	if req.noReply {
+		fd.numActiveRequests -= 1
+		delete(fd.completions, req.hdr.Unique)
 	}
 
-	return bytesRead, nil
+	return int64(n), nil
 }
 
 // PWrite implements vfs.FileDescriptionImpl.PWrite.
 func (fd *DeviceFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
 	// Operations on /dev/fuse don't make sense until a FUSE filesystem is mounted.
-	if !fd.mounted {
+	if fd.fs == nil {
 		return 0, syserror.EPERM
 	}
 
@@ -211,10 +239,15 @@ func (fd *DeviceFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.
 // writeLocked implements writing to the fuse device while locked with DeviceFD.mu.
 func (fd *DeviceFD) writeLocked(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
 	// Operations on /dev/fuse don't make sense until a FUSE filesystem is mounted.
-	if !fd.mounted {
+	if fd.fs == nil {
 		return 0, syserror.EPERM
 	}
 
+	// Return ENODEV if the filesystem is umounted.
+	if fd.fs.umounted {
+		return 0, syserror.ENODEV
+	}
+
 	var cn, n int64
 	hdrLen := uint32((*linux.FUSEHeaderOut)(nil).SizeBytes())
 
@@ -276,7 +309,8 @@ func (fd *DeviceFD) writeLocked(ctx context.Context, src usermem.IOSequence, opt
 
 			fut, ok := fd.completions[hdr.Unique]
 			if !ok {
-				// Server sent us a response for a request we never sent?
+				// Server sent us a response for a request we never sent,
+				// or for which we already received a reply (e.g. aborted), an unlikely event.
 				return 0, syserror.EINVAL
 			}
 
@@ -307,8 +341,23 @@ func (fd *DeviceFD) writeLocked(ctx context.Context, src usermem.IOSequence, opt
 
 // Readiness implements vfs.FileDescriptionImpl.Readiness.
 func (fd *DeviceFD) Readiness(mask waiter.EventMask) waiter.EventMask {
+	fd.mu.Lock()
+	defer fd.mu.Unlock()
+	return fd.readinessLocked(mask)
+}
+
+// readinessLocked implements checking the readiness of the fuse device while
+// locked with DeviceFD.mu.
+func (fd *DeviceFD) readinessLocked(mask waiter.EventMask) waiter.EventMask {
 	var ready waiter.EventMask
-	ready |= waiter.EventOut // FD is always writable
+
+	if fd.fs.umounted {
+		ready |= waiter.EventErr
+		return ready & mask
+	}
+
+	// FD is always writable.
+	ready |= waiter.EventOut
 	if !fd.queue.Empty() {
 		// Have reqs available, FD is readable.
 		ready |= waiter.EventIn
@@ -330,7 +379,7 @@ func (fd *DeviceFD) EventUnregister(e *waiter.Entry) {
 // Seek implements vfs.FileDescriptionImpl.Seek.
 func (fd *DeviceFD) Seek(ctx context.Context, offset int64, whence int32) (int64, error) {
 	// Operations on /dev/fuse don't make sense until a FUSE filesystem is mounted.
-	if !fd.mounted {
+	if fd.fs == nil {
 		return 0, syserror.EPERM
 	}
 
@@ -338,59 +387,59 @@ func (fd *DeviceFD) Seek(ctx context.Context, offset int64, whence int32) (int64
 }
 
 // sendResponse sends a response to the waiting task (if any).
+//
+// Preconditions: fd.mu must be held.
 func (fd *DeviceFD) sendResponse(ctx context.Context, fut *futureResponse) error {
-	// See if the running task need to perform some action before returning.
-	// Since we just finished writing the future, we can be sure that
-	// getResponse generates a populated response.
-	if err := fd.noReceiverAction(ctx, fut.getResponse()); err != nil {
-		return err
-	}
+	// Signal the task waiting on a response if any.
+	defer close(fut.ch)
 
 	// Signal that the queue is no longer full.
 	select {
 	case fd.fullQueueCh <- struct{}{}:
 	default:
 	}
-	fd.numActiveRequests -= 1
+	fd.numActiveRequests--
+
+	if fut.async {
+		return fd.asyncCallBack(ctx, fut.getResponse())
+	}
 
-	// Signal the task waiting on a response.
-	close(fut.ch)
 	return nil
 }
 
-// sendError sends an error response to the waiting task (if any).
-func (fd *DeviceFD) sendError(ctx context.Context, errno int32, req *Request) error {
+// sendError sends an error response to the waiting task (if any) by calling sendResponse().
+//
+// Preconditions: fd.mu must be held.
+func (fd *DeviceFD) sendError(ctx context.Context, errno int32, unique linux.FUSEOpID) error {
 	// Return the error to the calling task.
 	outHdrLen := uint32((*linux.FUSEHeaderOut)(nil).SizeBytes())
 	respHdr := linux.FUSEHeaderOut{
 		Len:    outHdrLen,
 		Error:  errno,
-		Unique: req.hdr.Unique,
+		Unique: unique,
 	}
 
 	fut, ok := fd.completions[respHdr.Unique]
 	if !ok {
-		// Server sent us a response for a request we never sent?
+		// A response for a request we never sent,
+		// or for which we already received a reply (e.g. aborted).
 		return syserror.EINVAL
 	}
 	delete(fd.completions, respHdr.Unique)
 
 	fut.hdr = &respHdr
-	if err := fd.sendResponse(ctx, fut); err != nil {
-		return err
-	}
-
-	return nil
+	return fd.sendResponse(ctx, fut)
 }
 
-// noReceiverAction has the calling kernel.Task do some action if its known that no
-// receiver is going to be waiting on the future channel. This is to be used by:
-// FUSE_INIT.
-func (fd *DeviceFD) noReceiverAction(ctx context.Context, r *Response) error {
-	if r.opcode == linux.FUSE_INIT {
+// asyncCallBack executes pre-defined callback function for async requests.
+// Currently used by: FUSE_INIT.
+func (fd *DeviceFD) asyncCallBack(ctx context.Context, r *Response) error {
+	switch r.opcode {
+	case linux.FUSE_INIT:
 		creds := auth.CredentialsFromContext(ctx)
 		rootUserNs := kernel.KernelFromContext(ctx).RootUserNamespace()
 		return fd.fs.conn.InitRecv(r, creds.HasCapabilityIn(linux.CAP_SYS_ADMIN, rootUserNs))
+		// TODO(gvisor.dev/issue/3247): support async read: correctly process the response.
 	}
 
 	return nil
diff --git a/pkg/sentry/fsimpl/fuse/dev_test.go b/pkg/sentry/fsimpl/fuse/dev_test.go
index c18921dd8..5986133e9 100644
--- a/pkg/sentry/fsimpl/fuse/dev_test.go
+++ b/pkg/sentry/fsimpl/fuse/dev_test.go
@@ -16,12 +16,10 @@ package fuse
 
 import (
 	"fmt"
-	"io"
 	"math/rand"
 	"testing"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
-	"gvisor.dev/gvisor/pkg/marshal"
 	"gvisor.dev/gvisor/pkg/sentry/fsimpl/testutil"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
@@ -35,10 +33,6 @@ import (
 // will simply echo the payload back with the appropriate headers.
 const echoTestOpcode linux.FUSEOpcode = 1000
 
-type testPayload struct {
-	data uint32
-}
-
 // TestFUSECommunication tests that the communication layer between the Sentry and the
 // FUSE server daemon works as expected.
 func TestFUSECommunication(t *testing.T) {
@@ -327,102 +321,3 @@ func fuseServerRun(t *testing.T, s *testutil.System, k *kernel.Kernel, fd *vfs.F
 		}
 	}
 }
-
-func setup(t *testing.T) *testutil.System {
-	k, err := testutil.Boot()
-	if err != nil {
-		t.Fatalf("Error creating kernel: %v", err)
-	}
-
-	ctx := k.SupervisorContext()
-	creds := auth.CredentialsFromContext(ctx)
-
-	k.VFS().MustRegisterFilesystemType(Name, &FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
-		AllowUserList:  true,
-		AllowUserMount: true,
-	})
-
-	mntns, err := k.VFS().NewMountNamespace(ctx, creds, "", "tmpfs", &vfs.MountOptions{})
-	if err != nil {
-		t.Fatalf("NewMountNamespace(): %v", err)
-	}
-
-	return testutil.NewSystem(ctx, t, k.VFS(), mntns)
-}
-
-// newTestConnection creates a fuse connection that the sentry can communicate with
-// and the FD for the server to communicate with.
-func newTestConnection(system *testutil.System, k *kernel.Kernel, maxActiveRequests uint64) (*connection, *vfs.FileDescription, error) {
-	vfsObj := &vfs.VirtualFilesystem{}
-	fuseDev := &DeviceFD{}
-
-	if err := vfsObj.Init(system.Ctx); err != nil {
-		return nil, nil, err
-	}
-
-	vd := vfsObj.NewAnonVirtualDentry("genCountFD")
-	defer vd.DecRef(system.Ctx)
-	if err := fuseDev.vfsfd.Init(fuseDev, linux.O_RDWR|linux.O_CREAT, vd.Mount(), vd.Dentry(), &vfs.FileDescriptionOptions{}); err != nil {
-		return nil, nil, err
-	}
-
-	fsopts := filesystemOptions{
-		maxActiveRequests: maxActiveRequests,
-	}
-	fs, err := NewFUSEFilesystem(system.Ctx, 0, &fsopts, &fuseDev.vfsfd)
-	if err != nil {
-		return nil, nil, err
-	}
-
-	return fs.conn, &fuseDev.vfsfd, nil
-}
-
-// SizeBytes implements marshal.Marshallable.SizeBytes.
-func (t *testPayload) SizeBytes() int {
-	return 4
-}
-
-// MarshalBytes implements marshal.Marshallable.MarshalBytes.
-func (t *testPayload) MarshalBytes(dst []byte) {
-	usermem.ByteOrder.PutUint32(dst[:4], t.data)
-}
-
-// UnmarshalBytes implements marshal.Marshallable.UnmarshalBytes.
-func (t *testPayload) UnmarshalBytes(src []byte) {
-	*t = testPayload{data: usermem.ByteOrder.Uint32(src[:4])}
-}
-
-// Packed implements marshal.Marshallable.Packed.
-func (t *testPayload) Packed() bool {
-	return true
-}
-
-// MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
-func (t *testPayload) MarshalUnsafe(dst []byte) {
-	t.MarshalBytes(dst)
-}
-
-// UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
-func (t *testPayload) UnmarshalUnsafe(src []byte) {
-	t.UnmarshalBytes(src)
-}
-
-// CopyOutN implements marshal.Marshallable.CopyOutN.
-func (t *testPayload) CopyOutN(cc marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
-	panic("not implemented")
-}
-
-// CopyOut implements marshal.Marshallable.CopyOut.
-func (t *testPayload) CopyOut(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
-	panic("not implemented")
-}
-
-// CopyIn implements marshal.Marshallable.CopyIn.
-func (t *testPayload) CopyIn(cc marshal.CopyContext, addr usermem.Addr) (int, error) {
-	panic("not implemented")
-}
-
-// WriteTo implements io.WriterTo.WriteTo.
-func (t *testPayload) WriteTo(w io.Writer) (int64, error) {
-	panic("not implemented")
-}
diff --git a/pkg/sentry/fsimpl/fuse/directory.go b/pkg/sentry/fsimpl/fuse/directory.go
new file mode 100644
index 000000000..ee77dbaa3
--- /dev/null
+++ b/pkg/sentry/fsimpl/fuse/directory.go
@@ -0,0 +1,105 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package fuse
+
+import (
+	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/syserror"
+	"gvisor.dev/gvisor/pkg/usermem"
+)
+
+type directoryFD struct {
+	fileDescription
+}
+
+// Allocate implements directoryFD.Allocate.
+func (*directoryFD) Allocate(ctx context.Context, mode, offset, length uint64) error {
+	return syserror.EISDIR
+}
+
+// PRead implements FileDescriptionImpl.PRead.
+func (*directoryFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
+	return 0, syserror.EISDIR
+}
+
+// Read implements FileDescriptionImpl.Read.
+func (*directoryFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
+	return 0, syserror.EISDIR
+}
+
+// PWrite implements FileDescriptionImpl.PWrite.
+func (*directoryFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
+	return 0, syserror.EISDIR
+}
+
+// Write implements FileDescriptionImpl.Write.
+func (*directoryFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
+	return 0, syserror.EISDIR
+}
+
+// IterDirents implements FileDescriptionImpl.IterDirents.
+func (dir *directoryFD) IterDirents(ctx context.Context, callback vfs.IterDirentsCallback) error {
+	fusefs := dir.inode().fs
+	task, creds := kernel.TaskFromContext(ctx), auth.CredentialsFromContext(ctx)
+
+	in := linux.FUSEReadIn{
+		Fh:     dir.Fh,
+		Offset: uint64(atomic.LoadInt64(&dir.off)),
+		Size:   linux.FUSE_PAGE_SIZE,
+		Flags:  dir.statusFlags(),
+	}
+
+	// TODO(gVisor.dev/issue/3404): Support FUSE_READDIRPLUS.
+	req, err := fusefs.conn.NewRequest(creds, uint32(task.ThreadID()), dir.inode().nodeID, linux.FUSE_READDIR, &in)
+	if err != nil {
+		return err
+	}
+
+	res, err := fusefs.conn.Call(task, req)
+	if err != nil {
+		return err
+	}
+	if err := res.Error(); err != nil {
+		return err
+	}
+
+	var out linux.FUSEDirents
+	if err := res.UnmarshalPayload(&out); err != nil {
+		return err
+	}
+
+	for _, fuseDirent := range out.Dirents {
+		nextOff := int64(fuseDirent.Meta.Off)
+		dirent := vfs.Dirent{
+			Name:    fuseDirent.Name,
+			Type:    uint8(fuseDirent.Meta.Type),
+			Ino:     fuseDirent.Meta.Ino,
+			NextOff: nextOff,
+		}
+
+		if err := callback.Handle(dirent); err != nil {
+			return err
+		}
+		atomic.StoreInt64(&dir.off, nextOff)
+	}
+
+	return nil
+}
diff --git a/pkg/sentry/fsimpl/fuse/file.go b/pkg/sentry/fsimpl/fuse/file.go
new file mode 100644
index 000000000..83f2816b7
--- /dev/null
+++ b/pkg/sentry/fsimpl/fuse/file.go
@@ -0,0 +1,133 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package fuse
+
+import (
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs"
+	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/usermem"
+)
+
+// fileDescription implements vfs.FileDescriptionImpl for fuse.
+type fileDescription struct {
+	vfsfd vfs.FileDescription
+	vfs.FileDescriptionDefaultImpl
+	vfs.DentryMetadataFileDescriptionImpl
+	vfs.NoLockFD
+
+	// the file handle used in userspace.
+	Fh uint64
+
+	// Nonseekable is indicate cannot perform seek on a file.
+	Nonseekable bool
+
+	// DirectIO suggest fuse to use direct io operation.
+	DirectIO bool
+
+	// OpenFlag is the flag returned by open.
+	OpenFlag uint32
+
+	// off is the file offset.
+	off int64
+}
+
+func (fd *fileDescription) dentry() *kernfs.Dentry {
+	return fd.vfsfd.Dentry().Impl().(*kernfs.Dentry)
+}
+
+func (fd *fileDescription) inode() *inode {
+	return fd.dentry().Inode().(*inode)
+}
+
+func (fd *fileDescription) filesystem() *vfs.Filesystem {
+	return fd.vfsfd.VirtualDentry().Mount().Filesystem()
+}
+
+func (fd *fileDescription) statusFlags() uint32 {
+	return fd.vfsfd.StatusFlags()
+}
+
+// Release implements vfs.FileDescriptionImpl.Release.
+func (fd *fileDescription) Release(ctx context.Context) {
+	// no need to release if FUSE server doesn't implement Open.
+	conn := fd.inode().fs.conn
+	if conn.noOpen {
+		return
+	}
+
+	in := linux.FUSEReleaseIn{
+		Fh:    fd.Fh,
+		Flags: fd.statusFlags(),
+	}
+	// TODO(gvisor.dev/issue/3245): add logic when we support file lock owner.
+	var opcode linux.FUSEOpcode
+	if fd.inode().Mode().IsDir() {
+		opcode = linux.FUSE_RELEASEDIR
+	} else {
+		opcode = linux.FUSE_RELEASE
+	}
+	kernelTask := kernel.TaskFromContext(ctx)
+	// ignoring errors and FUSE server reply is analogous to Linux's behavior.
+	req, err := conn.NewRequest(auth.CredentialsFromContext(ctx), uint32(kernelTask.ThreadID()), fd.inode().nodeID, opcode, &in)
+	if err != nil {
+		// No way to invoke Call() with an errored request.
+		return
+	}
+	// The reply will be ignored since no callback is defined in asyncCallBack().
+	conn.CallAsync(kernelTask, req)
+}
+
+// PRead implements vfs.FileDescriptionImpl.PRead.
+func (fd *fileDescription) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
+	return 0, nil
+}
+
+// Read implements vfs.FileDescriptionImpl.Read.
+func (fd *fileDescription) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
+	return 0, nil
+}
+
+// PWrite implements vfs.FileDescriptionImpl.PWrite.
+func (fd *fileDescription) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
+	return 0, nil
+}
+
+// Write implements vfs.FileDescriptionImpl.Write.
+func (fd *fileDescription) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
+	return 0, nil
+}
+
+// Seek implements vfs.FileDescriptionImpl.Seek.
+func (fd *fileDescription) Seek(ctx context.Context, offset int64, whence int32) (int64, error) {
+	return 0, nil
+}
+
+// Stat implements vfs.FileDescriptionImpl.Stat.
+func (fd *fileDescription) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error) {
+	fs := fd.filesystem()
+	inode := fd.inode()
+	return inode.Stat(ctx, fs, opts)
+}
+
+// SetStat implements vfs.FileDescriptionImpl.SetStat.
+func (fd *fileDescription) SetStat(ctx context.Context, opts vfs.SetStatOptions) error {
+	fs := fd.filesystem()
+	creds := auth.CredentialsFromContext(ctx)
+	return fd.inode().setAttr(ctx, fs, creds, opts, true, fd.Fh)
+}
diff --git a/pkg/sentry/fsimpl/fuse/fusefs.go b/pkg/sentry/fsimpl/fuse/fusefs.go
index 810819ae4..f1ffd2343 100644
--- a/pkg/sentry/fsimpl/fuse/fusefs.go
+++ b/pkg/sentry/fsimpl/fuse/fusefs.go
@@ -16,21 +16,30 @@
 package fuse
 
 import (
+	"math"
 	"strconv"
+	"sync"
+	"sync/atomic"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/log"
+	"gvisor.dev/gvisor/pkg/marshal"
 	"gvisor.dev/gvisor/pkg/sentry/fsimpl/kernfs"
 	"gvisor.dev/gvisor/pkg/sentry/kernel"
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
 	"gvisor.dev/gvisor/pkg/syserror"
+	"gvisor.dev/gvisor/pkg/waiter"
 )
 
 // Name is the default filesystem name.
 const Name = "fuse"
 
+// maxActiveRequestsDefault is the default setting controlling the upper bound
+// on the number of active requests at any given time.
+const maxActiveRequestsDefault = 10000
+
 // FilesystemType implements vfs.FilesystemType.
 type FilesystemType struct{}
 
@@ -56,6 +65,11 @@ type filesystemOptions struct {
 	// exist at any time. Any further requests will block when trying to
 	// Call the server.
 	maxActiveRequests uint64
+
+	// maxRead is the max number of bytes to read,
+	// specified as "max_read" in fs parameters.
+	// If not specified by user, use math.MaxUint32 as default value.
+	maxRead uint32
 }
 
 // filesystem implements vfs.FilesystemImpl.
@@ -69,6 +83,9 @@ type filesystem struct {
 
 	// opts is the options the fusefs is initialized with.
 	opts *filesystemOptions
+
+	// umounted is true if filesystem.Release() has been called.
+	umounted bool
 }
 
 // Name implements vfs.FilesystemType.Name.
@@ -142,14 +159,29 @@ func (fsType FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
 	// Set the maxInFlightRequests option.
 	fsopts.maxActiveRequests = maxActiveRequestsDefault
 
+	if maxReadStr, ok := mopts["max_read"]; ok {
+		delete(mopts, "max_read")
+		maxRead, err := strconv.ParseUint(maxReadStr, 10, 32)
+		if err != nil {
+			log.Warningf("%s.GetFilesystem: invalid max_read: max_read=%s", fsType.Name(), maxReadStr)
+			return nil, nil, syserror.EINVAL
+		}
+		if maxRead < fuseMinMaxRead {
+			maxRead = fuseMinMaxRead
+		}
+		fsopts.maxRead = uint32(maxRead)
+	} else {
+		fsopts.maxRead = math.MaxUint32
+	}
+
 	// Check for unparsed options.
 	if len(mopts) != 0 {
-		log.Warningf("%s.GetFilesystem: unknown options: %v", fsType.Name(), mopts)
+		log.Warningf("%s.GetFilesystem: unsupported or unknown options: %v", fsType.Name(), mopts)
 		return nil, nil, syserror.EINVAL
 	}
 
 	// Create a new FUSE filesystem.
-	fs, err := NewFUSEFilesystem(ctx, devMinor, &fsopts, fuseFd)
+	fs, err := newFUSEFilesystem(ctx, devMinor, &fsopts, fuseFd)
 	if err != nil {
 		log.Warningf("%s.NewFUSEFilesystem: failed with error: %v", fsType.Name(), err)
 		return nil, nil, err
@@ -165,26 +197,27 @@ func (fsType FilesystemType) GetFilesystem(ctx context.Context, vfsObj *vfs.Virt
 	}
 
 	// root is the fusefs root directory.
-	root := fs.newInode(creds, fsopts.rootMode)
+	root := fs.newRootInode(creds, fsopts.rootMode)
 
 	return fs.VFSFilesystem(), root.VFSDentry(), nil
 }
 
-// NewFUSEFilesystem creates a new FUSE filesystem.
-func NewFUSEFilesystem(ctx context.Context, devMinor uint32, opts *filesystemOptions, device *vfs.FileDescription) (*filesystem, error) {
-	fs := &filesystem{
-		devMinor: devMinor,
-		opts:     opts,
-	}
-
-	conn, err := newFUSEConnection(ctx, device, opts.maxActiveRequests)
+// newFUSEFilesystem creates a new FUSE filesystem.
+func newFUSEFilesystem(ctx context.Context, devMinor uint32, opts *filesystemOptions, device *vfs.FileDescription) (*filesystem, error) {
+	conn, err := newFUSEConnection(ctx, device, opts)
 	if err != nil {
 		log.Warningf("fuse.NewFUSEFilesystem: NewFUSEConnection failed with error: %v", err)
 		return nil, syserror.EINVAL
 	}
 
-	fs.conn = conn
 	fuseFD := device.Impl().(*DeviceFD)
+
+	fs := &filesystem{
+		devMinor: devMinor,
+		opts:     opts,
+		conn:     conn,
+	}
+
 	fuseFD.fs = fs
 
 	return fs, nil
@@ -192,6 +225,15 @@ func NewFUSEFilesystem(ctx context.Context, devMinor uint32, opts *filesystemOpt
 
 // Release implements vfs.FilesystemImpl.Release.
 func (fs *filesystem) Release(ctx context.Context) {
+	fs.conn.fd.mu.Lock()
+
+	fs.umounted = true
+	fs.conn.Abort(ctx)
+	// Notify all the waiters on this fd.
+	fs.conn.fd.waitQueue.Notify(waiter.EventIn)
+
+	fs.conn.fd.mu.Unlock()
+
 	fs.Filesystem.VFSFilesystem().VirtualFilesystem().PutAnonBlockDevMinor(fs.devMinor)
 	fs.Filesystem.Release(ctx)
 }
@@ -205,14 +247,49 @@ type inode struct {
 	kernfs.InodeNotSymlink
 	kernfs.OrderedChildren
 
+	dentry kernfs.Dentry
+
+	// the owning filesystem. fs is immutable.
+	fs *filesystem
+
+	// metaDataMu protects the metadata of this inode.
+	metadataMu sync.Mutex
+
+	nodeID uint64
+
 	locks vfs.FileLocks
 
-	dentry kernfs.Dentry
+	// size of the file.
+	size uint64
+
+	// attributeVersion is the version of inode's attributes.
+	attributeVersion uint64
+
+	// attributeTime is the remaining vaild time of attributes.
+	attributeTime uint64
+
+	// version of the inode.
+	version uint64
+
+	// link is result of following a symbolic link.
+	link string
+}
+
+func (fs *filesystem) newRootInode(creds *auth.Credentials, mode linux.FileMode) *kernfs.Dentry {
+	i := &inode{fs: fs}
+	i.InodeAttrs.Init(creds, linux.UNNAMED_MAJOR, fs.devMinor, 1, linux.ModeDirectory|0755)
+	i.OrderedChildren.Init(kernfs.OrderedChildrenOptions{})
+	i.dentry.Init(i)
+	i.nodeID = 1
+
+	return &i.dentry
 }
 
-func (fs *filesystem) newInode(creds *auth.Credentials, mode linux.FileMode) *kernfs.Dentry {
-	i := &inode{}
-	i.InodeAttrs.Init(creds, linux.UNNAMED_MAJOR, fs.devMinor, fs.NextIno(), linux.ModeDirectory|0755)
+func (fs *filesystem) newInode(nodeID uint64, attr linux.FUSEAttr) *kernfs.Dentry {
+	i := &inode{fs: fs, nodeID: nodeID}
+	creds := auth.Credentials{EffectiveKGID: auth.KGID(attr.UID), EffectiveKUID: auth.KUID(attr.UID)}
+	i.InodeAttrs.Init(&creds, linux.UNNAMED_MAJOR, fs.devMinor, fs.NextIno(), linux.FileMode(attr.Mode))
+	atomic.StoreUint64(&i.size, attr.Size)
 	i.OrderedChildren.Init(kernfs.OrderedChildrenOptions{})
 	i.EnableLeakCheck()
 	i.dentry.Init(i)
@@ -222,13 +299,301 @@ func (fs *filesystem) newInode(creds *auth.Credentials, mode linux.FileMode) *ke
 
 // Open implements kernfs.Inode.Open.
 func (i *inode) Open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentry, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
-	fd, err := kernfs.NewGenericDirectoryFD(rp.Mount(), vfsd, &i.OrderedChildren, &i.locks, &opts, kernfs.GenericDirectoryFDOptions{
-		SeekEnd: kernfs.SeekEndStaticEntries,
-	})
+	isDir := i.InodeAttrs.Mode().IsDir()
+	// return error if specified to open directory but inode is not a directory.
+	if !isDir && opts.Mode.IsDir() {
+		return nil, syserror.ENOTDIR
+	}
+	if opts.Flags&linux.O_LARGEFILE == 0 && atomic.LoadUint64(&i.size) > linux.MAX_NON_LFS {
+		return nil, syserror.EOVERFLOW
+	}
+
+	var fd *fileDescription
+	var fdImpl vfs.FileDescriptionImpl
+	if isDir {
+		directoryFD := &directoryFD{}
+		fd = &(directoryFD.fileDescription)
+		fdImpl = directoryFD
+	} else {
+		regularFD := &regularFileFD{}
+		fd = &(regularFD.fileDescription)
+		fdImpl = regularFD
+	}
+	// FOPEN_KEEP_CACHE is the defualt flag for noOpen.
+	fd.OpenFlag = linux.FOPEN_KEEP_CACHE
+
+	// Only send open request when FUSE server support open or is opening a directory.
+	if !i.fs.conn.noOpen || isDir {
+		kernelTask := kernel.TaskFromContext(ctx)
+		if kernelTask == nil {
+			log.Warningf("fusefs.Inode.Open: couldn't get kernel task from context")
+			return nil, syserror.EINVAL
+		}
+
+		// Build the request.
+		var opcode linux.FUSEOpcode
+		if isDir {
+			opcode = linux.FUSE_OPENDIR
+		} else {
+			opcode = linux.FUSE_OPEN
+		}
+
+		in := linux.FUSEOpenIn{Flags: opts.Flags & ^uint32(linux.O_CREAT|linux.O_EXCL|linux.O_NOCTTY)}
+		if !i.fs.conn.atomicOTrunc {
+			in.Flags &= ^uint32(linux.O_TRUNC)
+		}
+
+		req, err := i.fs.conn.NewRequest(auth.CredentialsFromContext(ctx), uint32(kernelTask.ThreadID()), i.nodeID, opcode, &in)
+		if err != nil {
+			return nil, err
+		}
+
+		// Send the request and receive the reply.
+		res, err := i.fs.conn.Call(kernelTask, req)
+		if err != nil {
+			return nil, err
+		}
+		if err := res.Error(); err == syserror.ENOSYS && !isDir {
+			i.fs.conn.noOpen = true
+		} else if err != nil {
+			return nil, err
+		} else {
+			out := linux.FUSEOpenOut{}
+			if err := res.UnmarshalPayload(&out); err != nil {
+				return nil, err
+			}
+
+			// Process the reply.
+			fd.OpenFlag = out.OpenFlag
+			if isDir {
+				fd.OpenFlag &= ^uint32(linux.FOPEN_DIRECT_IO)
+			}
+
+			fd.Fh = out.Fh
+		}
+	}
+
+	// TODO(gvisor.dev/issue/3234): invalidate mmap after implemented it for FUSE Inode
+	fd.DirectIO = fd.OpenFlag&linux.FOPEN_DIRECT_IO != 0
+	fdOptions := &vfs.FileDescriptionOptions{}
+	if fd.OpenFlag&linux.FOPEN_NONSEEKABLE != 0 {
+		fdOptions.DenyPRead = true
+		fdOptions.DenyPWrite = true
+		fd.Nonseekable = true
+	}
+
+	// If we don't send SETATTR before open (which is indicated by atomicOTrunc)
+	// and O_TRUNC is set, update the inode's version number and clean existing data
+	// by setting the file size to 0.
+	if i.fs.conn.atomicOTrunc && opts.Flags&linux.O_TRUNC != 0 {
+		i.fs.conn.mu.Lock()
+		i.fs.conn.attributeVersion++
+		i.attributeVersion = i.fs.conn.attributeVersion
+		atomic.StoreUint64(&i.size, 0)
+		i.fs.conn.mu.Unlock()
+		i.attributeTime = 0
+	}
+
+	if err := fd.vfsfd.Init(fdImpl, opts.Flags, rp.Mount(), vfsd, fdOptions); err != nil {
+		return nil, err
+	}
+	return &fd.vfsfd, nil
+}
+
+// Lookup implements kernfs.Inode.Lookup.
+func (i *inode) Lookup(ctx context.Context, name string) (*vfs.Dentry, error) {
+	in := linux.FUSELookupIn{Name: name}
+	return i.newEntry(ctx, name, 0, linux.FUSE_LOOKUP, &in)
+}
+
+// IterDirents implements kernfs.Inode.IterDirents.
+func (*inode) IterDirents(ctx context.Context, callback vfs.IterDirentsCallback, offset, relOffset int64) (int64, error) {
+	return offset, nil
+}
+
+// Valid implements kernfs.Inode.Valid.
+func (*inode) Valid(ctx context.Context) bool {
+	return true
+}
+
+// NewFile implements kernfs.Inode.NewFile.
+func (i *inode) NewFile(ctx context.Context, name string, opts vfs.OpenOptions) (*vfs.Dentry, error) {
+	kernelTask := kernel.TaskFromContext(ctx)
+	if kernelTask == nil {
+		log.Warningf("fusefs.Inode.NewFile: couldn't get kernel task from context", i.nodeID)
+		return nil, syserror.EINVAL
+	}
+	in := linux.FUSECreateIn{
+		CreateMeta: linux.FUSECreateMeta{
+			Flags: opts.Flags,
+			Mode:  uint32(opts.Mode) | linux.S_IFREG,
+			Umask: uint32(kernelTask.FSContext().Umask()),
+		},
+		Name: name,
+	}
+	return i.newEntry(ctx, name, linux.S_IFREG, linux.FUSE_CREATE, &in)
+}
+
+// NewNode implements kernfs.Inode.NewNode.
+func (i *inode) NewNode(ctx context.Context, name string, opts vfs.MknodOptions) (*vfs.Dentry, error) {
+	in := linux.FUSEMknodIn{
+		MknodMeta: linux.FUSEMknodMeta{
+			Mode:  uint32(opts.Mode),
+			Rdev:  linux.MakeDeviceID(uint16(opts.DevMajor), opts.DevMinor),
+			Umask: uint32(kernel.TaskFromContext(ctx).FSContext().Umask()),
+		},
+		Name: name,
+	}
+	return i.newEntry(ctx, name, opts.Mode.FileType(), linux.FUSE_MKNOD, &in)
+}
+
+// NewSymlink implements kernfs.Inode.NewSymlink.
+func (i *inode) NewSymlink(ctx context.Context, name, target string) (*vfs.Dentry, error) {
+	in := linux.FUSESymLinkIn{
+		Name:   name,
+		Target: target,
+	}
+	return i.newEntry(ctx, name, linux.S_IFLNK, linux.FUSE_SYMLINK, &in)
+}
+
+// Unlink implements kernfs.Inode.Unlink.
+func (i *inode) Unlink(ctx context.Context, name string, child *vfs.Dentry) error {
+	kernelTask := kernel.TaskFromContext(ctx)
+	if kernelTask == nil {
+		log.Warningf("fusefs.Inode.newEntry: couldn't get kernel task from context", i.nodeID)
+		return syserror.EINVAL
+	}
+	in := linux.FUSEUnlinkIn{Name: name}
+	req, err := i.fs.conn.NewRequest(auth.CredentialsFromContext(ctx), uint32(kernelTask.ThreadID()), i.nodeID, linux.FUSE_UNLINK, &in)
+	if err != nil {
+		return err
+	}
+	res, err := i.fs.conn.Call(kernelTask, req)
+	if err != nil {
+		return err
+	}
+	// only return error, discard res.
+	if err := res.Error(); err != nil {
+		return err
+	}
+	return i.dentry.RemoveChildLocked(name, child)
+}
+
+// NewDir implements kernfs.Inode.NewDir.
+func (i *inode) NewDir(ctx context.Context, name string, opts vfs.MkdirOptions) (*vfs.Dentry, error) {
+	in := linux.FUSEMkdirIn{
+		MkdirMeta: linux.FUSEMkdirMeta{
+			Mode:  uint32(opts.Mode),
+			Umask: uint32(kernel.TaskFromContext(ctx).FSContext().Umask()),
+		},
+		Name: name,
+	}
+	return i.newEntry(ctx, name, linux.S_IFDIR, linux.FUSE_MKDIR, &in)
+}
+
+// RmDir implements kernfs.Inode.RmDir.
+func (i *inode) RmDir(ctx context.Context, name string, child *vfs.Dentry) error {
+	fusefs := i.fs
+	task, creds := kernel.TaskFromContext(ctx), auth.CredentialsFromContext(ctx)
+
+	in := linux.FUSERmDirIn{Name: name}
+	req, err := fusefs.conn.NewRequest(creds, uint32(task.ThreadID()), i.nodeID, linux.FUSE_RMDIR, &in)
+	if err != nil {
+		return err
+	}
+
+	res, err := i.fs.conn.Call(task, req)
+	if err != nil {
+		return err
+	}
+	if err := res.Error(); err != nil {
+		return err
+	}
+
+	// TODO(Before merging): When creating new nodes, should we add nodes to the ordered children?
+	// If so we'll probably need to call this. We will also need to add them with the writable flag when
+	// appropriate.
+	// return i.OrderedChildren.RmDir(ctx, name, child)
+
+	return nil
+}
+
+// newEntry calls FUSE server for entry creation and allocates corresponding entry according to response.
+// Shared by FUSE_MKNOD, FUSE_MKDIR, FUSE_SYMLINK, FUSE_LINK and FUSE_LOOKUP.
+func (i *inode) newEntry(ctx context.Context, name string, fileType linux.FileMode, opcode linux.FUSEOpcode, payload marshal.Marshallable) (*vfs.Dentry, error) {
+	kernelTask := kernel.TaskFromContext(ctx)
+	if kernelTask == nil {
+		log.Warningf("fusefs.Inode.newEntry: couldn't get kernel task from context", i.nodeID)
+		return nil, syserror.EINVAL
+	}
+	req, err := i.fs.conn.NewRequest(auth.CredentialsFromContext(ctx), uint32(kernelTask.ThreadID()), i.nodeID, opcode, payload)
+	if err != nil {
+		return nil, err
+	}
+	res, err := i.fs.conn.Call(kernelTask, req)
 	if err != nil {
 		return nil, err
 	}
-	return fd.VFSFileDescription(), nil
+	if err := res.Error(); err != nil {
+		return nil, err
+	}
+	out := linux.FUSEEntryOut{}
+	if err := res.UnmarshalPayload(&out); err != nil {
+		return nil, err
+	}
+	if opcode != linux.FUSE_LOOKUP && ((out.Attr.Mode&linux.S_IFMT)^uint32(fileType) != 0 || out.NodeID == 0 || out.NodeID == linux.FUSE_ROOT_ID) {
+		return nil, syserror.EIO
+	}
+	child := i.fs.newInode(out.NodeID, out.Attr)
+	if opcode == linux.FUSE_LOOKUP {
+		i.dentry.InsertChildLocked(name, child)
+	} else {
+		i.dentry.InsertChild(name, child)
+	}
+	return child.VFSDentry(), nil
+}
+
+// Getlink implements kernfs.Inode.Getlink.
+func (i *inode) Getlink(ctx context.Context, mnt *vfs.Mount) (vfs.VirtualDentry, string, error) {
+	path, err := i.Readlink(ctx, mnt)
+	return vfs.VirtualDentry{}, path, err
+}
+
+// Readlink implements kernfs.Inode.Readlink.
+func (i *inode) Readlink(ctx context.Context, mnt *vfs.Mount) (string, error) {
+	if i.Mode().FileType()&linux.S_IFLNK == 0 {
+		return "", syserror.EINVAL
+	}
+	if len(i.link) == 0 {
+		kernelTask := kernel.TaskFromContext(ctx)
+		if kernelTask == nil {
+			log.Warningf("fusefs.Inode.Readlink: couldn't get kernel task from context")
+			return "", syserror.EINVAL
+		}
+		req, err := i.fs.conn.NewRequest(auth.CredentialsFromContext(ctx), uint32(kernelTask.ThreadID()), i.nodeID, linux.FUSE_READLINK, &linux.FUSEEmptyIn{})
+		if err != nil {
+			return "", err
+		}
+		res, err := i.fs.conn.Call(kernelTask, req)
+		if err != nil {
+			return "", err
+		}
+		i.link = string(res.data[res.hdr.SizeBytes():])
+		if !mnt.Options().ReadOnly {
+			i.attributeTime = 0
+		}
+	}
+	return i.link, nil
+}
+
+// getFUSEAttr returns a linux.FUSEAttr of this inode stored in local cache.
+// TODO(gvisor.dev/issue/3679): Add support for other fields.
+func (i *inode) getFUSEAttr() linux.FUSEAttr {
+	return linux.FUSEAttr{
+		Ino:  i.Ino(),
+		Size: atomic.LoadUint64(&i.size),
+		Mode: uint32(i.Mode()),
+	}
 }
 
 // statFromFUSEAttr makes attributes from linux.FUSEAttr to linux.Statx. The
@@ -284,47 +649,89 @@ func statFromFUSEAttr(attr linux.FUSEAttr, mask, devMinor uint32) linux.Statx {
 	return stat
 }
 
-// Stat implements kernfs.Inode.Stat.
-func (i *inode) Stat(ctx context.Context, fs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) {
-	fusefs := fs.Impl().(*filesystem)
-	conn := fusefs.conn
-	task, creds := kernel.TaskFromContext(ctx), auth.CredentialsFromContext(ctx)
+// getAttr gets the attribute of this inode by issuing a FUSE_GETATTR request
+// or read from local cache. It updates the corresponding attributes if
+// necessary.
+func (i *inode) getAttr(ctx context.Context, fs *vfs.Filesystem, opts vfs.StatOptions, flags uint32, fh uint64) (linux.FUSEAttr, error) {
+	attributeVersion := atomic.LoadUint64(&i.fs.conn.attributeVersion)
+
+	// TODO(gvisor.dev/issue/3679): send the request only if
+	// - invalid local cache for fields specified in the opts.Mask
+	// - forced update
+	// - i.attributeTime expired
+	// If local cache is still valid, return local cache.
+	// Currently we always send a request,
+	// and we always set the metadata with the new result,
+	// unless attributeVersion has changed.
+
+	task := kernel.TaskFromContext(ctx)
 	if task == nil {
 		log.Warningf("couldn't get kernel task from context")
-		return linux.Statx{}, syserror.EINVAL
+		return linux.FUSEAttr{}, syserror.EINVAL
 	}
 
-	var in linux.FUSEGetAttrIn
-	// We don't set any attribute in the request, because in VFS2 fstat(2) will
-	// finally be translated into vfs.FilesystemImpl.StatAt() (see
-	// pkg/sentry/syscalls/linux/vfs2/stat.go), resulting in the same flow
-	// as stat(2). Thus GetAttrFlags and Fh variable will never be used in VFS2.
-	req, err := conn.NewRequest(creds, uint32(task.ThreadID()), i.Ino(), linux.FUSE_GETATTR, &in)
+	creds := auth.CredentialsFromContext(ctx)
+
+	in := linux.FUSEGetAttrIn{
+		GetAttrFlags: flags,
+		Fh:           fh,
+	}
+	req, err := i.fs.conn.NewRequest(creds, uint32(task.ThreadID()), i.nodeID, linux.FUSE_GETATTR, &in)
 	if err != nil {
-		return linux.Statx{}, err
+		return linux.FUSEAttr{}, err
 	}
 
-	res, err := conn.Call(task, req)
+	res, err := i.fs.conn.Call(task, req)
 	if err != nil {
-		return linux.Statx{}, err
+		return linux.FUSEAttr{}, err
 	}
 	if err := res.Error(); err != nil {
-		return linux.Statx{}, err
+		return linux.FUSEAttr{}, err
 	}
 
 	var out linux.FUSEGetAttrOut
 	if err := res.UnmarshalPayload(&out); err != nil {
-		return linux.Statx{}, err
+		return linux.FUSEAttr{}, err
+	}
+
+	// Local version is newer, return the local one.
+	// Skip the update.
+	if attributeVersion != 0 && atomic.LoadUint64(&i.attributeVersion) > attributeVersion {
+		return i.getFUSEAttr(), nil
 	}
 
-	// Set all metadata into kernfs.InodeAttrs.
-	if err := i.SetStat(ctx, fs, creds, vfs.SetStatOptions{
-		Stat: statFromFUSEAttr(out.Attr, linux.STATX_ALL, fusefs.devMinor),
+	// Set the metadata of kernfs.InodeAttrs.
+	if err := i.SetInodeStat(ctx, fs, creds, vfs.SetStatOptions{
+		Stat: statFromFUSEAttr(out.Attr, linux.STATX_ALL, i.fs.devMinor),
 	}); err != nil {
+		return linux.FUSEAttr{}, err
+	}
+
+	// Set the size if no error (after SetStat() check).
+	atomic.StoreUint64(&i.size, out.Attr.Size)
+
+	return out.Attr, nil
+}
+
+// reviseAttr attempts to update the attributes for internal purposes
+// by calling getAttr with a pre-specified mask.
+// Used by read, write, lseek.
+func (i *inode) reviseAttr(ctx context.Context, flags uint32, fh uint64) error {
+	// Never need atime for internal purposes.
+	_, err := i.getAttr(ctx, i.fs.VFSFilesystem(), vfs.StatOptions{
+		Mask: linux.STATX_BASIC_STATS &^ linux.STATX_ATIME,
+	}, flags, fh)
+	return err
+}
+
+// Stat implements kernfs.Inode.Stat.
+func (i *inode) Stat(ctx context.Context, fs *vfs.Filesystem, opts vfs.StatOptions) (linux.Statx, error) {
+	attr, err := i.getAttr(ctx, fs, opts, 0, 0)
+	if err != nil {
 		return linux.Statx{}, err
 	}
 
-	return statFromFUSEAttr(out.Attr, opts.Mask, fusefs.devMinor), nil
+	return statFromFUSEAttr(attr, opts.Mask, i.fs.devMinor), nil
 }
 
 // DecRef implements kernfs.Inode.
@@ -337,3 +744,84 @@ func (i *inode) StatFS(ctx context.Context, fs *vfs.Filesystem) (linux.Statfs, e
 	// TODO(gvisor.dev/issues/3413): Complete the implementation of statfs.
 	return vfs.GenericStatFS(linux.FUSE_SUPER_MAGIC), nil
 }
+
+// fattrMaskFromStats converts vfs.SetStatOptions.Stat.Mask to linux stats mask
+// aligned with the attribute mask defined in include/linux/fs.h.
+func fattrMaskFromStats(mask uint32) uint32 {
+	var fuseAttrMask uint32
+	maskMap := map[uint32]uint32{
+		linux.STATX_MODE:  linux.FATTR_MODE,
+		linux.STATX_UID:   linux.FATTR_UID,
+		linux.STATX_GID:   linux.FATTR_GID,
+		linux.STATX_SIZE:  linux.FATTR_SIZE,
+		linux.STATX_ATIME: linux.FATTR_ATIME,
+		linux.STATX_MTIME: linux.FATTR_MTIME,
+		linux.STATX_CTIME: linux.FATTR_CTIME,
+	}
+	for statxMask, fattrMask := range maskMap {
+		if mask&statxMask != 0 {
+			fuseAttrMask |= fattrMask
+		}
+	}
+	return fuseAttrMask
+}
+
+// SetStat implements kernfs.Inode.SetStat.
+func (i *inode) SetStat(ctx context.Context, fs *vfs.Filesystem, creds *auth.Credentials, opts vfs.SetStatOptions) error {
+	return i.setAttr(ctx, fs, creds, opts, false, 0)
+}
+
+func (i *inode) setAttr(ctx context.Context, fs *vfs.Filesystem, creds *auth.Credentials, opts vfs.SetStatOptions, useFh bool, fh uint64) error {
+	conn := i.fs.conn
+	task := kernel.TaskFromContext(ctx)
+	if task == nil {
+		log.Warningf("couldn't get kernel task from context")
+		return syserror.EINVAL
+	}
+
+	// We should retain the original file type when assigning new mode.
+	fileType := uint16(i.Mode()) & linux.S_IFMT
+	fattrMask := fattrMaskFromStats(opts.Stat.Mask)
+	if useFh {
+		fattrMask |= linux.FATTR_FH
+	}
+	in := linux.FUSESetAttrIn{
+		Valid:     fattrMask,
+		Fh:        fh,
+		Size:      opts.Stat.Size,
+		Atime:     uint64(opts.Stat.Atime.Sec),
+		Mtime:     uint64(opts.Stat.Mtime.Sec),
+		Ctime:     uint64(opts.Stat.Ctime.Sec),
+		AtimeNsec: opts.Stat.Atime.Nsec,
+		MtimeNsec: opts.Stat.Mtime.Nsec,
+		CtimeNsec: opts.Stat.Ctime.Nsec,
+		Mode:      uint32(fileType | opts.Stat.Mode),
+		UID:       opts.Stat.UID,
+		GID:       opts.Stat.GID,
+	}
+	req, err := conn.NewRequest(creds, uint32(task.ThreadID()), i.nodeID, linux.FUSE_SETATTR, &in)
+	if err != nil {
+		return err
+	}
+
+	res, err := conn.Call(task, req)
+	if err != nil {
+		return err
+	}
+	if err := res.Error(); err != nil {
+		return err
+	}
+	out := linux.FUSEGetAttrOut{}
+	if err := res.UnmarshalPayload(&out); err != nil {
+		return err
+	}
+
+	// Set the metadata of kernfs.InodeAttrs.
+	if err := i.SetInodeStat(ctx, fs, creds, vfs.SetStatOptions{
+		Stat: statFromFUSEAttr(out.Attr, linux.STATX_ALL, i.fs.devMinor),
+	}); err != nil {
+		return err
+	}
+
+	return nil
+}
diff --git a/pkg/sentry/fsimpl/fuse/read_write.go b/pkg/sentry/fsimpl/fuse/read_write.go
new file mode 100644
index 000000000..625d1547f
--- /dev/null
+++ b/pkg/sentry/fsimpl/fuse/read_write.go
@@ -0,0 +1,242 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package fuse
+
+import (
+	"io"
+	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/log"
+	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/syserror"
+	"gvisor.dev/gvisor/pkg/usermem"
+)
+
+// ReadInPages sends FUSE_READ requests for the size after round it up to
+// a multiple of page size, blocks on it for reply, processes the reply
+// and returns the payload (or joined payloads) as a byte slice.
+// This is used for the general purpose reading.
+// We do not support direct IO (which read the exact number of bytes)
+// at this moment.
+func (fs *filesystem) ReadInPages(ctx context.Context, fd *regularFileFD, off uint64, size uint32) ([][]byte, uint32, error) {
+	attributeVersion := atomic.LoadUint64(&fs.conn.attributeVersion)
+
+	t := kernel.TaskFromContext(ctx)
+	if t == nil {
+		log.Warningf("fusefs.Read: couldn't get kernel task from context")
+		return nil, 0, syserror.EINVAL
+	}
+
+	// Round up to a multiple of page size.
+	readSize, _ := usermem.PageRoundUp(uint64(size))
+
+	// One request cannnot exceed either maxRead or maxPages.
+	maxPages := fs.conn.maxRead >> usermem.PageShift
+	if maxPages > uint32(fs.conn.maxPages) {
+		maxPages = uint32(fs.conn.maxPages)
+	}
+
+	var outs [][]byte
+	var sizeRead uint32
+
+	// readSize is a multiple of usermem.PageSize.
+	// Always request bytes as a multiple of pages.
+	pagesRead, pagesToRead := uint32(0), uint32(readSize>>usermem.PageShift)
+
+	// Reuse the same struct for unmarshalling to avoid unnecessary memory allocation.
+	in := linux.FUSEReadIn{
+		Fh:        fd.Fh,
+		LockOwner: 0, // TODO(gvisor.dev/issue/3245): file lock
+		ReadFlags: 0, // TODO(gvisor.dev/issue/3245): |= linux.FUSE_READ_LOCKOWNER
+		Flags:     fd.statusFlags(),
+	}
+
+	// This loop is intended for fragmented read where the bytes to read is
+	// larger than either the maxPages or maxRead.
+	// For the majority of reads with normal size, this loop should only
+	// execute once.
+	for pagesRead < pagesToRead {
+		pagesCanRead := pagesToRead - pagesRead
+		if pagesCanRead > maxPages {
+			pagesCanRead = maxPages
+		}
+
+		in.Offset = off + (uint64(pagesRead) << usermem.PageShift)
+		in.Size = pagesCanRead << usermem.PageShift
+
+		req, err := fs.conn.NewRequest(auth.CredentialsFromContext(ctx), uint32(t.ThreadID()), fd.inode().nodeID, linux.FUSE_READ, &in)
+		if err != nil {
+			return nil, 0, err
+		}
+
+		// TODO(gvisor.dev/issue/3247): support async read.
+
+		res, err := fs.conn.Call(t, req)
+		if err != nil {
+			return nil, 0, err
+		}
+		if err := res.Error(); err != nil {
+			return nil, 0, err
+		}
+
+		// Not enough bytes in response,
+		// either we reached EOF,
+		// or the FUSE server sends back a response
+		// that cannot even fit the hdr.
+		if len(res.data) <= res.hdr.SizeBytes() {
+			// We treat both case as EOF here for now
+			// since there is no reliable way to detect
+			// the over-short hdr case.
+			break
+		}
+
+		// Directly using the slice to avoid extra copy.
+		out := res.data[res.hdr.SizeBytes():]
+
+		outs = append(outs, out)
+		sizeRead += uint32(len(out))
+
+		pagesRead += pagesCanRead
+	}
+
+	defer fs.ReadCallback(ctx, fd, off, size, sizeRead, attributeVersion)
+
+	// No bytes returned: offset >= EOF.
+	if len(outs) == 0 {
+		return nil, 0, io.EOF
+	}
+
+	return outs, sizeRead, nil
+}
+
+// ReadCallback updates several information after receiving a read response.
+// Due to readahead, sizeRead can be larger than size.
+func (fs *filesystem) ReadCallback(ctx context.Context, fd *regularFileFD, off uint64, size uint32, sizeRead uint32, attributeVersion uint64) {
+	// TODO(gvisor.dev/issue/3247): support async read.
+	// If this is called by an async read, correctly process it.
+	// May need to update the signature.
+
+	i := fd.inode()
+	// TODO(gvisor.dev/issue/1193): Invalidate or update atime.
+
+	// Reached EOF.
+	if sizeRead < size {
+		// TODO(gvisor.dev/issue/3630): If we have writeback cache, then we need to fill this hole.
+		// Might need to update the buf to be returned from the Read().
+
+		// Update existing size.
+		newSize := off + uint64(sizeRead)
+		fs.conn.mu.Lock()
+		if attributeVersion == i.attributeVersion && newSize < atomic.LoadUint64(&i.size) {
+			fs.conn.attributeVersion++
+			i.attributeVersion = i.fs.conn.attributeVersion
+			atomic.StoreUint64(&i.size, newSize)
+		}
+		fs.conn.mu.Unlock()
+	}
+}
+
+// Write sends FUSE_WRITE requests and return the bytes
+// written according to the response.
+//
+// Preconditions: len(data) == size.
+func (fs *filesystem) Write(ctx context.Context, fd *regularFileFD, off uint64, size uint32, data []byte) (uint32, error) {
+	t := kernel.TaskFromContext(ctx)
+	if t == nil {
+		log.Warningf("fusefs.Read: couldn't get kernel task from context")
+		return 0, syserror.EINVAL
+	}
+
+	// One request cannnot exceed either maxWrite or maxPages.
+	maxWrite := uint32(fs.conn.maxPages) << usermem.PageShift
+	if maxWrite > fs.conn.maxWrite {
+		maxWrite = fs.conn.maxWrite
+	}
+
+	// Reuse the same struct for unmarshalling to avoid unnecessary memory allocation.
+	in := linux.FUSEWriteIn{
+		Fh: fd.Fh,
+		// TODO(gvisor.dev/issue/3245): file lock
+		LockOwner: 0,
+		// TODO(gvisor.dev/issue/3245): |= linux.FUSE_READ_LOCKOWNER
+		// TODO(gvisor.dev/issue/3237): |= linux.FUSE_WRITE_CACHE (not added yet)
+		WriteFlags: 0,
+		Flags:      fd.statusFlags(),
+	}
+
+	var written uint32
+
+	// This loop is intended for fragmented write where the bytes to write is
+	// larger than either the maxWrite or maxPages or when bigWrites is false.
+	// Unless a small value for max_write is explicitly used, this loop
+	// is expected to execute only once for the majority of the writes.
+	for written < size {
+		toWrite := size - written
+
+		// Limit the write size to one page.
+		// Note that the bigWrites flag is obsolete,
+		// latest libfuse always sets it on.
+		if !fs.conn.bigWrites && toWrite > usermem.PageSize {
+			toWrite = usermem.PageSize
+		}
+
+		// Limit the write size to maxWrite.
+		if toWrite > maxWrite {
+			toWrite = maxWrite
+		}
+
+		in.Offset = off + uint64(written)
+		in.Size = toWrite
+
+		req, err := fs.conn.NewRequest(auth.CredentialsFromContext(ctx), uint32(t.ThreadID()), fd.inode().nodeID, linux.FUSE_WRITE, &in)
+		if err != nil {
+			return 0, err
+		}
+
+		req.payload = data[written : written+toWrite]
+
+		// TODO(gvisor.dev/issue/3247): support async write.
+
+		res, err := fs.conn.Call(t, req)
+		if err != nil {
+			return 0, err
+		}
+		if err := res.Error(); err != nil {
+			return 0, err
+		}
+
+		out := linux.FUSEWriteOut{}
+		if err := res.UnmarshalPayload(&out); err != nil {
+			return 0, err
+		}
+
+		// Write more than requested? EIO.
+		if out.Size > toWrite {
+			return 0, syserror.EIO
+		}
+
+		written += out.Size
+
+		// Break if short write. Not necessarily an error.
+		if out.Size != toWrite {
+			break
+		}
+	}
+
+	return written, nil
+}
diff --git a/pkg/sentry/fsimpl/fuse/regular_file.go b/pkg/sentry/fsimpl/fuse/regular_file.go
new file mode 100644
index 000000000..5bdd096c3
--- /dev/null
+++ b/pkg/sentry/fsimpl/fuse/regular_file.go
@@ -0,0 +1,230 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package fuse
+
+import (
+	"io"
+	"math"
+	"sync"
+	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/context"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/syserror"
+	"gvisor.dev/gvisor/pkg/usermem"
+)
+
+type regularFileFD struct {
+	fileDescription
+
+	// off is the file offset.
+	off int64
+	// offMu protects off.
+	offMu sync.Mutex
+}
+
+// PRead implements vfs.FileDescriptionImpl.PRead.
+func (fd *regularFileFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
+	if offset < 0 {
+		return 0, syserror.EINVAL
+	}
+
+	// Check that flags are supported.
+	//
+	// TODO(gvisor.dev/issue/2601): Support select preadv2 flags.
+	if opts.Flags&^linux.RWF_HIPRI != 0 {
+		return 0, syserror.EOPNOTSUPP
+	}
+
+	size := dst.NumBytes()
+	if size == 0 {
+		// Early return if count is 0.
+		return 0, nil
+	} else if size > math.MaxUint32 {
+		// FUSE only supports uint32 for size.
+		// Overflow.
+		return 0, syserror.EINVAL
+	}
+
+	// TODO(gvisor.dev/issue/3678): Add direct IO support.
+
+	inode := fd.inode()
+
+	// Reading beyond EOF, update file size if outdated.
+	if uint64(offset+size) > atomic.LoadUint64(&inode.size) {
+		if err := inode.reviseAttr(ctx, linux.FUSE_GETATTR_FH, fd.Fh); err != nil {
+			return 0, err
+		}
+		// If the offset after update is still too large, return error.
+		if uint64(offset) >= atomic.LoadUint64(&inode.size) {
+			return 0, io.EOF
+		}
+	}
+
+	// Truncate the read with updated file size.
+	fileSize := atomic.LoadUint64(&inode.size)
+	if uint64(offset+size) > fileSize {
+		size = int64(fileSize) - offset
+	}
+
+	buffers, n, err := inode.fs.ReadInPages(ctx, fd, uint64(offset), uint32(size))
+	if err != nil {
+		return 0, err
+	}
+
+	// TODO(gvisor.dev/issue/3237): support indirect IO (e.g. caching),
+	// store the bytes that were read ahead.
+
+	// Update the number of bytes to copy for short read.
+	if n < uint32(size) {
+		size = int64(n)
+	}
+
+	// Copy the bytes read to the dst.
+	// This loop is intended for fragmented reads.
+	// For the majority of reads, this loop only execute once.
+	var copied int64
+	for _, buffer := range buffers {
+		toCopy := int64(len(buffer))
+		if copied+toCopy > size {
+			toCopy = size - copied
+		}
+		cp, err := dst.DropFirst64(copied).CopyOut(ctx, buffer[:toCopy])
+		if err != nil {
+			return 0, err
+		}
+		if int64(cp) != toCopy {
+			return 0, syserror.EIO
+		}
+		copied += toCopy
+	}
+
+	return copied, nil
+}
+
+// Read implements vfs.FileDescriptionImpl.Read.
+func (fd *regularFileFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
+	fd.offMu.Lock()
+	n, err := fd.PRead(ctx, dst, fd.off, opts)
+	fd.off += n
+	fd.offMu.Unlock()
+	return n, err
+}
+
+// PWrite implements vfs.FileDescriptionImpl.PWrite.
+func (fd *regularFileFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
+	n, _, err := fd.pwrite(ctx, src, offset, opts)
+	return n, err
+}
+
+// Write implements vfs.FileDescriptionImpl.Write.
+func (fd *regularFileFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
+	fd.offMu.Lock()
+	n, off, err := fd.pwrite(ctx, src, fd.off, opts)
+	fd.off = off
+	fd.offMu.Unlock()
+	return n, err
+}
+
+// pwrite returns the number of bytes written, final offset and error. The
+// final offset should be ignored by PWrite.
+func (fd *regularFileFD) pwrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (written, finalOff int64, err error) {
+	if offset < 0 {
+		return 0, offset, syserror.EINVAL
+	}
+
+	// Check that flags are supported.
+	//
+	// TODO(gvisor.dev/issue/2601): Support select preadv2 flags.
+	if opts.Flags&^linux.RWF_HIPRI != 0 {
+		return 0, offset, syserror.EOPNOTSUPP
+	}
+
+	inode := fd.inode()
+	inode.metadataMu.Lock()
+	defer inode.metadataMu.Unlock()
+
+	// If the file is opened with O_APPEND, update offset to file size.
+	// Note: since our Open() implements the interface of kernfs,
+	// and kernfs currently does not support O_APPEND, this will never
+	// be true before we switch out from kernfs.
+	if fd.vfsfd.StatusFlags()&linux.O_APPEND != 0 {
+		// Locking inode.metadataMu is sufficient for reading size
+		offset = int64(inode.size)
+	}
+
+	srclen := src.NumBytes()
+
+	if srclen > math.MaxUint32 {
+		// FUSE only supports uint32 for size.
+		// Overflow.
+		return 0, offset, syserror.EINVAL
+	}
+	if end := offset + srclen; end < offset {
+		// Overflow.
+		return 0, offset, syserror.EINVAL
+	}
+
+	srclen, err = vfs.CheckLimit(ctx, offset, srclen)
+	if err != nil {
+		return 0, offset, err
+	}
+
+	if srclen == 0 {
+		// Return before causing any side effects.
+		return 0, offset, nil
+	}
+
+	src = src.TakeFirst64(srclen)
+
+	// TODO(gvisor.dev/issue/3237): Add cache support:
+	// buffer cache. Ideally we write from src to our buffer cache first.
+	// The slice passed to fs.Write() should be a slice from buffer cache.
+	data := make([]byte, srclen)
+	// Reason for making a copy here: connection.Call() blocks on kerneltask,
+	// which in turn acquires mm.activeMu lock. Functions like CopyInTo() will
+	// attemp to acquire the mm.activeMu lock as well -> deadlock.
+	// We must finish reading from the userspace memory before
+	// t.Block() deactivates it.
+	cp, err := src.CopyIn(ctx, data)
+	if err != nil {
+		return 0, offset, err
+	}
+	if int64(cp) != srclen {
+		return 0, offset, syserror.EIO
+	}
+
+	n, err := fd.inode().fs.Write(ctx, fd, uint64(offset), uint32(srclen), data)
+	if err != nil {
+		return 0, offset, err
+	}
+
+	if n == 0 {
+		// We have checked srclen != 0 previously.
+		// If err == nil, then it's a short write and we return EIO.
+		return 0, offset, syserror.EIO
+	}
+
+	written = int64(n)
+	finalOff = offset + written
+
+	if finalOff > int64(inode.size) {
+		atomic.StoreUint64(&inode.size, uint64(finalOff))
+		atomic.AddUint64(&inode.fs.conn.attributeVersion, 1)
+	}
+
+	return
+}
diff --git a/pkg/sentry/fsimpl/fuse/request_response.go b/pkg/sentry/fsimpl/fuse/request_response.go
new file mode 100644
index 000000000..7fa00569b
--- /dev/null
+++ b/pkg/sentry/fsimpl/fuse/request_response.go
@@ -0,0 +1,229 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package fuse
+
+import (
+	"fmt"
+	"syscall"
+
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/marshal"
+	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/usermem"
+)
+
+// fuseInitRes is a variable-length wrapper of linux.FUSEInitOut. The FUSE
+// server may implement an older version of FUSE protocol, which contains a
+// linux.FUSEInitOut with less attributes.
+//
+// Dynamically-sized objects cannot be marshalled.
+type fuseInitRes struct {
+	marshal.StubMarshallable
+
+	// initOut contains the response from the FUSE server.
+	initOut linux.FUSEInitOut
+
+	// initLen is the total length of bytes of the response.
+	initLen uint32
+}
+
+// UnmarshalBytes deserializes src to the initOut attribute in a fuseInitRes.
+func (r *fuseInitRes) UnmarshalBytes(src []byte) {
+	out := &r.initOut
+
+	// Introduced before FUSE kernel version 7.13.
+	out.Major = uint32(usermem.ByteOrder.Uint32(src[:4]))
+	src = src[4:]
+	out.Minor = uint32(usermem.ByteOrder.Uint32(src[:4]))
+	src = src[4:]
+	out.MaxReadahead = uint32(usermem.ByteOrder.Uint32(src[:4]))
+	src = src[4:]
+	out.Flags = uint32(usermem.ByteOrder.Uint32(src[:4]))
+	src = src[4:]
+	out.MaxBackground = uint16(usermem.ByteOrder.Uint16(src[:2]))
+	src = src[2:]
+	out.CongestionThreshold = uint16(usermem.ByteOrder.Uint16(src[:2]))
+	src = src[2:]
+	out.MaxWrite = uint32(usermem.ByteOrder.Uint32(src[:4]))
+	src = src[4:]
+
+	// Introduced in FUSE kernel version 7.23.
+	if len(src) >= 4 {
+		out.TimeGran = uint32(usermem.ByteOrder.Uint32(src[:4]))
+		src = src[4:]
+	}
+	// Introduced in FUSE kernel version 7.28.
+	if len(src) >= 2 {
+		out.MaxPages = uint16(usermem.ByteOrder.Uint16(src[:2]))
+		src = src[2:]
+	}
+}
+
+// SizeBytes is the size of the payload of the FUSE_INIT response.
+func (r *fuseInitRes) SizeBytes() int {
+	return int(r.initLen)
+}
+
+// Ordinary requests have even IDs, while interrupts IDs are odd.
+// Used to increment the unique ID for each FUSE request.
+var reqIDStep uint64 = 2
+
+// Request represents a FUSE operation request that hasn't been sent to the
+// server yet.
+//
+// +stateify savable
+type Request struct {
+	requestEntry
+
+	id   linux.FUSEOpID
+	hdr  *linux.FUSEHeaderIn
+	data []byte
+
+	// payload for this request: extra bytes to write after
+	// the data slice. Used by FUSE_WRITE.
+	payload []byte
+
+	// If this request is async.
+	async bool
+	// If we don't care its response.
+	// Manually set by the caller.
+	noReply bool
+}
+
+// NewRequest creates a new request that can be sent to the FUSE server.
+func (conn *connection) NewRequest(creds *auth.Credentials, pid uint32, ino uint64, opcode linux.FUSEOpcode, payload marshal.Marshallable) (*Request, error) {
+	conn.fd.mu.Lock()
+	defer conn.fd.mu.Unlock()
+	conn.fd.nextOpID += linux.FUSEOpID(reqIDStep)
+
+	hdrLen := (*linux.FUSEHeaderIn)(nil).SizeBytes()
+	hdr := linux.FUSEHeaderIn{
+		Len:    uint32(hdrLen + payload.SizeBytes()),
+		Opcode: opcode,
+		Unique: conn.fd.nextOpID,
+		NodeID: ino,
+		UID:    uint32(creds.EffectiveKUID),
+		GID:    uint32(creds.EffectiveKGID),
+		PID:    pid,
+	}
+
+	buf := make([]byte, hdr.Len)
+
+	// TODO(gVisor.dev/issue/3698): Use the unsafe version once go_marshal is safe to use again.
+	hdr.MarshalBytes(buf[:hdrLen])
+	payload.MarshalBytes(buf[hdrLen:])
+
+	return &Request{
+		id:   hdr.Unique,
+		hdr:  &hdr,
+		data: buf,
+	}, nil
+}
+
+// futureResponse represents an in-flight request, that may or may not have
+// completed yet. Convert it to a resolved Response by calling Resolve, but note
+// that this may block.
+//
+// +stateify savable
+type futureResponse struct {
+	opcode linux.FUSEOpcode
+	ch     chan struct{}
+	hdr    *linux.FUSEHeaderOut
+	data   []byte
+
+	// If this request is async.
+	async bool
+}
+
+// newFutureResponse creates a future response to a FUSE request.
+func newFutureResponse(req *Request) *futureResponse {
+	return &futureResponse{
+		opcode: req.hdr.Opcode,
+		ch:     make(chan struct{}),
+		async:  req.async,
+	}
+}
+
+// resolve blocks the task until the server responds to its corresponding request,
+// then returns a resolved response.
+func (f *futureResponse) resolve(t *kernel.Task) (*Response, error) {
+	// Return directly for async requests.
+	if f.async {
+		return nil, nil
+	}
+
+	if err := t.Block(f.ch); err != nil {
+		return nil, err
+	}
+
+	return f.getResponse(), nil
+}
+
+// getResponse creates a Response from the data the futureResponse has.
+func (f *futureResponse) getResponse() *Response {
+	return &Response{
+		opcode: f.opcode,
+		hdr:    *f.hdr,
+		data:   f.data,
+	}
+}
+
+// Response represents an actual response from the server, including the
+// response payload.
+//
+// +stateify savable
+type Response struct {
+	opcode linux.FUSEOpcode
+	hdr    linux.FUSEHeaderOut
+	data   []byte
+}
+
+// Error returns the error of the FUSE call.
+func (r *Response) Error() error {
+	errno := r.hdr.Error
+	if errno >= 0 {
+		return nil
+	}
+
+	sysErrNo := syscall.Errno(-errno)
+	return error(sysErrNo)
+}
+
+// DataLen returns the size of the response without the header.
+func (r *Response) DataLen() uint32 {
+	return r.hdr.Len - uint32(r.hdr.SizeBytes())
+}
+
+// UnmarshalPayload unmarshals the response data into m.
+func (r *Response) UnmarshalPayload(m marshal.Marshallable) error {
+	hdrLen := r.hdr.SizeBytes()
+	haveDataLen := r.hdr.Len - uint32(hdrLen)
+	wantDataLen := uint32(m.SizeBytes())
+
+	if haveDataLen < wantDataLen {
+		return fmt.Errorf("payload too small. Minimum data lenth required: %d,  but got data length %d", wantDataLen, haveDataLen)
+	}
+
+	// The response data is empty unless there is some payload. And so, doesn't
+	// need to be unmarshalled.
+	if r.data == nil {
+		return nil
+	}
+
+	// TODO(gVisor.dev/issue/3698): Use the unsafe version once go_marshal is safe to use again.
+	m.UnmarshalBytes(r.data[hdrLen:])
+	return nil
+}
diff --git a/pkg/sentry/fsimpl/fuse/utils_test.go b/pkg/sentry/fsimpl/fuse/utils_test.go
new file mode 100644
index 000000000..e1d9e3365
--- /dev/null
+++ b/pkg/sentry/fsimpl/fuse/utils_test.go
@@ -0,0 +1,132 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package fuse
+
+import (
+	"io"
+	"testing"
+
+	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/marshal"
+	"gvisor.dev/gvisor/pkg/sentry/fsimpl/testutil"
+	"gvisor.dev/gvisor/pkg/sentry/kernel"
+	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
+	"gvisor.dev/gvisor/pkg/sentry/vfs"
+	"gvisor.dev/gvisor/pkg/usermem"
+)
+
+func setup(t *testing.T) *testutil.System {
+	k, err := testutil.Boot()
+	if err != nil {
+		t.Fatalf("Error creating kernel: %v", err)
+	}
+
+	ctx := k.SupervisorContext()
+	creds := auth.CredentialsFromContext(ctx)
+
+	k.VFS().MustRegisterFilesystemType(Name, &FilesystemType{}, &vfs.RegisterFilesystemTypeOptions{
+		AllowUserList:  true,
+		AllowUserMount: true,
+	})
+
+	mntns, err := k.VFS().NewMountNamespace(ctx, creds, "", "tmpfs", &vfs.MountOptions{})
+	if err != nil {
+		t.Fatalf("NewMountNamespace(): %v", err)
+	}
+
+	return testutil.NewSystem(ctx, t, k.VFS(), mntns)
+}
+
+// newTestConnection creates a fuse connection that the sentry can communicate with
+// and the FD for the server to communicate with.
+func newTestConnection(system *testutil.System, k *kernel.Kernel, maxActiveRequests uint64) (*connection, *vfs.FileDescription, error) {
+	vfsObj := &vfs.VirtualFilesystem{}
+	fuseDev := &DeviceFD{}
+
+	if err := vfsObj.Init(system.Ctx); err != nil {
+		return nil, nil, err
+	}
+
+	vd := vfsObj.NewAnonVirtualDentry("genCountFD")
+	defer vd.DecRef(system.Ctx)
+	if err := fuseDev.vfsfd.Init(fuseDev, linux.O_RDWR|linux.O_CREAT, vd.Mount(), vd.Dentry(), &vfs.FileDescriptionOptions{}); err != nil {
+		return nil, nil, err
+	}
+
+	fsopts := filesystemOptions{
+		maxActiveRequests: maxActiveRequests,
+	}
+	fs, err := newFUSEFilesystem(system.Ctx, 0, &fsopts, &fuseDev.vfsfd)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return fs.conn, &fuseDev.vfsfd, nil
+}
+
+type testPayload struct {
+	marshal.StubMarshallable
+	data uint32
+}
+
+// SizeBytes implements marshal.Marshallable.SizeBytes.
+func (t *testPayload) SizeBytes() int {
+	return 4
+}
+
+// MarshalBytes implements marshal.Marshallable.MarshalBytes.
+func (t *testPayload) MarshalBytes(dst []byte) {
+	usermem.ByteOrder.PutUint32(dst[:4], t.data)
+}
+
+// UnmarshalBytes implements marshal.Marshallable.UnmarshalBytes.
+func (t *testPayload) UnmarshalBytes(src []byte) {
+	*t = testPayload{data: usermem.ByteOrder.Uint32(src[:4])}
+}
+
+// Packed implements marshal.Marshallable.Packed.
+func (t *testPayload) Packed() bool {
+	return true
+}
+
+// MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.
+func (t *testPayload) MarshalUnsafe(dst []byte) {
+	t.MarshalBytes(dst)
+}
+
+// UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.
+func (t *testPayload) UnmarshalUnsafe(src []byte) {
+	t.UnmarshalBytes(src)
+}
+
+// CopyOutN implements marshal.Marshallable.CopyOutN.
+func (t *testPayload) CopyOutN(task marshal.CopyContext, addr usermem.Addr, limit int) (int, error) {
+	panic("not implemented")
+}
+
+// CopyOut implements marshal.Marshallable.CopyOut.
+func (t *testPayload) CopyOut(task marshal.CopyContext, addr usermem.Addr) (int, error) {
+	panic("not implemented")
+}
+
+// CopyIn implements marshal.Marshallable.CopyIn.
+func (t *testPayload) CopyIn(task marshal.CopyContext, addr usermem.Addr) (int, error) {
+	panic("not implemented")
+}
+
+// WriteTo implements io.WriterTo.WriteTo.
+func (t *testPayload) WriteTo(w io.Writer) (int64, error) {
+	panic("not implemented")
+}
diff --git a/pkg/sentry/fsimpl/kernfs/filesystem.go b/pkg/sentry/fsimpl/kernfs/filesystem.go
index d7d3e8f48..49f6a0f1d 100644
--- a/pkg/sentry/fsimpl/kernfs/filesystem.go
+++ b/pkg/sentry/fsimpl/kernfs/filesystem.go
@@ -140,7 +140,7 @@ func (fs *Filesystem) revalidateChildLocked(ctx context.Context, vfsObj *vfs.Vir
 		}
 		// Reference on childVFSD dropped by a corresponding Valid.
 		child = childVFSD.Impl().(*Dentry)
-		parent.insertChildLocked(name, child)
+		parent.InsertChildLocked(name, child)
 	}
 	return child, nil
 }
@@ -548,7 +548,7 @@ func (fs *Filesystem) ReadlinkAt(ctx context.Context, rp *vfs.ResolvingPath) (st
 	if !d.Impl().(*Dentry).isSymlink() {
 		return "", syserror.EINVAL
 	}
-	return inode.Readlink(ctx)
+	return inode.Readlink(ctx, rp.Mount())
 }
 
 // RenameAt implements vfs.FilesystemImpl.RenameAt.
@@ -657,6 +657,10 @@ func (fs *Filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa
 func (fs *Filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error {
 	fs.mu.Lock()
 	defer fs.mu.Unlock()
+
+	// Store the name before walkExistingLocked as rp will be advanced past the
+	// name in the following call.
+	name := rp.Component()
 	vfsd, inode, err := fs.walkExistingLocked(ctx, rp)
 	fs.processDeferredDecRefsLocked(ctx)
 	if err != nil {
@@ -686,7 +690,8 @@ func (fs *Filesystem) RmdirAt(ctx context.Context, rp *vfs.ResolvingPath) error
 	if err := virtfs.PrepareDeleteDentry(mntns, vfsd); err != nil {
 		return err
 	}
-	if err := parentDentry.inode.RmDir(ctx, rp.Component(), vfsd); err != nil {
+
+	if err := parentDentry.inode.RmDir(ctx, name, vfsd); err != nil {
 		virtfs.AbortDeleteDentry(vfsd)
 		return err
 	}
@@ -765,6 +770,10 @@ func (fs *Filesystem) SymlinkAt(ctx context.Context, rp *vfs.ResolvingPath, targ
 func (fs *Filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error {
 	fs.mu.Lock()
 	defer fs.mu.Unlock()
+
+	// Store the name before walkExistingLocked as rp will be advanced past the
+	// name in the following call.
+	name := rp.Component()
 	vfsd, _, err := fs.walkExistingLocked(ctx, rp)
 	fs.processDeferredDecRefsLocked(ctx)
 	if err != nil {
@@ -790,7 +799,7 @@ func (fs *Filesystem) UnlinkAt(ctx context.Context, rp *vfs.ResolvingPath) error
 	if err := virtfs.PrepareDeleteDentry(mntns, vfsd); err != nil {
 		return err
 	}
-	if err := parentDentry.inode.Unlink(ctx, rp.Component(), vfsd); err != nil {
+	if err := parentDentry.inode.Unlink(ctx, name, vfsd); err != nil {
 		virtfs.AbortDeleteDentry(vfsd)
 		return err
 	}
diff --git a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
index 74408e322..c2109cf76 100644
--- a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
+++ b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go
@@ -172,7 +172,7 @@ func (InodeNoDynamicLookup) Valid(ctx context.Context) bool {
 type InodeNotSymlink struct{}
 
 // Readlink implements Inode.Readlink.
-func (InodeNotSymlink) Readlink(context.Context) (string, error) {
+func (InodeNotSymlink) Readlink(context.Context, *vfs.Mount) (string, error) {
 	return "", syserror.EINVAL
 }
 
@@ -256,6 +256,13 @@ func (a *InodeAttrs) Stat(context.Context, *vfs.Filesystem, vfs.StatOptions) (li
 
 // SetStat implements Inode.SetStat.
 func (a *InodeAttrs) SetStat(ctx context.Context, fs *vfs.Filesystem, creds *auth.Credentials, opts vfs.SetStatOptions) error {
+	return a.SetInodeStat(ctx, fs, creds, opts)
+}
+
+// SetInodeStat sets the corresponding attributes from opts to InodeAttrs.
+// This function can be used by other kernfs-based filesystem implementation to
+// sets the unexported attributes into kernfs.InodeAttrs.
+func (a *InodeAttrs) SetInodeStat(ctx context.Context, fs *vfs.Filesystem, creds *auth.Credentials, opts vfs.SetStatOptions) error {
 	if opts.Stat.Mask == 0 {
 		return nil
 	}
diff --git a/pkg/sentry/fsimpl/kernfs/kernfs.go b/pkg/sentry/fsimpl/kernfs/kernfs.go
index 88fcd54aa..163f26ceb 100644
--- a/pkg/sentry/fsimpl/kernfs/kernfs.go
+++ b/pkg/sentry/fsimpl/kernfs/kernfs.go
@@ -60,6 +60,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
 	"gvisor.dev/gvisor/pkg/sentry/vfs"
 	"gvisor.dev/gvisor/pkg/sync"
+	"gvisor.dev/gvisor/pkg/syserror"
 )
 
 // Filesystem mostly implements vfs.FilesystemImpl for a generic in-memory
@@ -246,15 +247,15 @@ func (d *Dentry) OnZeroWatches(context.Context) {}
 // Precondition: d must represent a directory inode.
 func (d *Dentry) InsertChild(name string, child *Dentry) {
 	d.dirMu.Lock()
-	d.insertChildLocked(name, child)
+	d.InsertChildLocked(name, child)
 	d.dirMu.Unlock()
 }
 
-// insertChildLocked is equivalent to InsertChild, with additional
+// InsertChildLocked is equivalent to InsertChild, with additional
 // preconditions.
 //
 // Precondition: d.dirMu must be locked.
-func (d *Dentry) insertChildLocked(name string, child *Dentry) {
+func (d *Dentry) InsertChildLocked(name string, child *Dentry) {
 	if !d.isDir() {
 		panic(fmt.Sprintf("InsertChild called on non-directory Dentry: %+v.", d))
 	}
@@ -267,6 +268,36 @@ func (d *Dentry) insertChildLocked(name string, child *Dentry) {
 	d.children[name] = child
 }
 
+// RemoveChild removes child from the vfs dentry cache. This does not update the
+// directory inode or modify the inode to be unlinked. So calling this on its own
+// isn't sufficient to remove a child from a directory.
+//
+// Precondition: d must represent a directory inode.
+func (d *Dentry) RemoveChild(name string, child *vfs.Dentry) error {
+	d.dirMu.Lock()
+	defer d.dirMu.Unlock()
+	return d.RemoveChildLocked(name, child)
+}
+
+// RemoveChildLocked is equivalent to RemoveChild, with additional
+// preconditions.
+//
+// Precondition: d.dirMu must be locked.
+func (d *Dentry) RemoveChildLocked(name string, child *vfs.Dentry) error {
+	if !d.isDir() {
+		panic(fmt.Sprintf("RemoveChild called on non-directory Dentry: %+v.", d))
+	}
+	c, ok := d.children[name]
+	if !ok {
+		return syserror.ENOENT
+	}
+	if &c.vfsd != child {
+		panic(fmt.Sprintf("Dentry hashed into inode doesn't match what vfs thinks! Child: %+v, vfs: %+v", c, child))
+	}
+	delete(d.children, name)
+	return nil
+}
+
 // Inode returns the dentry's inode.
 func (d *Dentry) Inode() Inode {
 	return d.inode
@@ -425,7 +456,7 @@ type inodeDynamicLookup interface {
 	Valid(ctx context.Context) bool
 
 	// IterDirents is used to iterate over dynamically created entries. It invokes
-	// cb on each entry in the directory represented by the FileDescription.
+	// cb on each entry in the directory represented by the Inode.
 	// 'offset' is the offset for the entire IterDirents call, which may include
 	// results from the caller (e.g. "." and ".."). 'relOffset' is the offset
 	// inside the entries returned by this IterDirents invocation. In other words,
@@ -437,7 +468,7 @@ type inodeDynamicLookup interface {
 type inodeSymlink interface {
 	// Readlink returns the target of a symbolic link. If an inode is not a
 	// symlink, the implementation should return EINVAL.
-	Readlink(ctx context.Context) (string, error)
+	Readlink(ctx context.Context, mnt *vfs.Mount) (string, error)
 
 	// Getlink returns the target of a symbolic link, as used by path
 	// resolution:
diff --git a/pkg/sentry/fsimpl/kernfs/symlink.go b/pkg/sentry/fsimpl/kernfs/symlink.go
index 64731a3e4..a9812fcef 100644
--- a/pkg/sentry/fsimpl/kernfs/symlink.go
+++ b/pkg/sentry/fsimpl/kernfs/symlink.go
@@ -52,7 +52,7 @@ func (s *StaticSymlink) Init(creds *auth.Credentials, devMajor uint32, devMinor
 }
 
 // Readlink implements Inode.
-func (s *StaticSymlink) Readlink(_ context.Context) (string, error) {
+func (s *StaticSymlink) Readlink(_ context.Context, _ *vfs.Mount) (string, error) {
 	return s.target, nil
 }
 
diff --git a/pkg/sentry/fsimpl/proc/task_fds.go b/pkg/sentry/fsimpl/proc/task_fds.go
index 94ec2ff69..47d744a57 100644
--- a/pkg/sentry/fsimpl/proc/task_fds.go
+++ b/pkg/sentry/fsimpl/proc/task_fds.go
@@ -214,7 +214,7 @@ func (fs *filesystem) newFDSymlink(task *kernel.Task, fd int32, ino uint64) *ker
 	return d
 }
 
-func (s *fdSymlink) Readlink(ctx context.Context) (string, error) {
+func (s *fdSymlink) Readlink(ctx context.Context, _ *vfs.Mount) (string, error) {
 	file, _ := getTaskFD(s.task, s.fd)
 	if file == nil {
 		return "", syserror.ENOENT
diff --git a/pkg/sentry/fsimpl/proc/task_files.go b/pkg/sentry/fsimpl/proc/task_files.go
index ce87b0d47..87726d8f7 100644
--- a/pkg/sentry/fsimpl/proc/task_files.go
+++ b/pkg/sentry/fsimpl/proc/task_files.go
@@ -668,7 +668,7 @@ func (fs *filesystem) newExeSymlink(task *kernel.Task, ino uint64) *kernfs.Dentr
 }
 
 // Readlink implements kernfs.Inode.
-func (s *exeSymlink) Readlink(ctx context.Context) (string, error) {
+func (s *exeSymlink) Readlink(ctx context.Context, _ *vfs.Mount) (string, error) {
 	if !kernel.ContextCanTrace(ctx, s.task, false) {
 		return "", syserror.EACCES
 	}
@@ -808,11 +808,11 @@ func (fs *filesystem) newNamespaceSymlink(task *kernel.Task, ino uint64, ns stri
 }
 
 // Readlink implements Inode.
-func (s *namespaceSymlink) Readlink(ctx context.Context) (string, error) {
+func (s *namespaceSymlink) Readlink(ctx context.Context, mnt *vfs.Mount) (string, error) {
 	if err := checkTaskState(s.task); err != nil {
 		return "", err
 	}
-	return s.StaticSymlink.Readlink(ctx)
+	return s.StaticSymlink.Readlink(ctx, mnt)
 }
 
 // Getlink implements Inode.Getlink.
diff --git a/pkg/sentry/fsimpl/proc/tasks_files.go b/pkg/sentry/fsimpl/proc/tasks_files.go
index 8c41729e4..68c541046 100644
--- a/pkg/sentry/fsimpl/proc/tasks_files.go
+++ b/pkg/sentry/fsimpl/proc/tasks_files.go
@@ -51,7 +51,7 @@ func (fs *filesystem) newSelfSymlink(creds *auth.Credentials, ino uint64, pidns
 	return d
 }
 
-func (s *selfSymlink) Readlink(ctx context.Context) (string, error) {
+func (s *selfSymlink) Readlink(ctx context.Context, _ *vfs.Mount) (string, error) {
 	t := kernel.TaskFromContext(ctx)
 	if t == nil {
 		// Who is reading this link?
@@ -64,8 +64,8 @@ func (s *selfSymlink) Readlink(ctx context.Context) (string, error) {
 	return strconv.FormatUint(uint64(tgid), 10), nil
 }
 
-func (s *selfSymlink) Getlink(ctx context.Context, _ *vfs.Mount) (vfs.VirtualDentry, string, error) {
-	target, err := s.Readlink(ctx)
+func (s *selfSymlink) Getlink(ctx context.Context, mnt *vfs.Mount) (vfs.VirtualDentry, string, error) {
+	target, err := s.Readlink(ctx, mnt)
 	return vfs.VirtualDentry{}, target, err
 }
 
@@ -94,7 +94,7 @@ func (fs *filesystem) newThreadSelfSymlink(creds *auth.Credentials, ino uint64,
 	return d
 }
 
-func (s *threadSelfSymlink) Readlink(ctx context.Context) (string, error) {
+func (s *threadSelfSymlink) Readlink(ctx context.Context, _ *vfs.Mount) (string, error) {
 	t := kernel.TaskFromContext(ctx)
 	if t == nil {
 		// Who is reading this link?
@@ -108,8 +108,8 @@ func (s *threadSelfSymlink) Readlink(ctx context.Context) (string, error) {
 	return fmt.Sprintf("%d/task/%d", tgid, tid), nil
 }
 
-func (s *threadSelfSymlink) Getlink(ctx context.Context, _ *vfs.Mount) (vfs.VirtualDentry, string, error) {
-	target, err := s.Readlink(ctx)
+func (s *threadSelfSymlink) Getlink(ctx context.Context, mnt *vfs.Mount) (vfs.VirtualDentry, string, error) {
+	target, err := s.Readlink(ctx, mnt)
 	return vfs.VirtualDentry{}, target, err
 }
 
diff --git a/pkg/syserror/syserror.go b/pkg/syserror/syserror.go
index fe9f50169..f516c8e46 100644
--- a/pkg/syserror/syserror.go
+++ b/pkg/syserror/syserror.go
@@ -33,6 +33,7 @@ var (
 	EBADFD       = error(syscall.EBADFD)
 	EBUSY        = error(syscall.EBUSY)
 	ECHILD       = error(syscall.ECHILD)
+	ECONNABORTED = error(syscall.ECONNABORTED)
 	ECONNREFUSED = error(syscall.ECONNREFUSED)
 	ECONNRESET   = error(syscall.ECONNRESET)
 	EDEADLK      = error(syscall.EDEADLK)
diff --git a/test/fuse/BUILD b/test/fuse/BUILD
index 56157c96b..8e31fdd41 100644
--- a/test/fuse/BUILD
+++ b/test/fuse/BUILD
@@ -5,5 +5,69 @@ package(licenses = ["notice"])
 syscall_test(
     fuse = "True",
     test = "//test/fuse/linux:stat_test",
-    vfs2 = "True",
+)
+
+syscall_test(
+    fuse = "True",
+    test = "//test/fuse/linux:open_test",
+)
+
+syscall_test(
+    fuse = "True",
+    test = "//test/fuse/linux:release_test",
+)
+
+syscall_test(
+    fuse = "True",
+    test = "//test/fuse/linux:mknod_test",
+)
+
+syscall_test(
+    fuse = "True",
+    test = "//test/fuse/linux:symlink_test",
+)
+
+syscall_test(
+    fuse = "True",
+    test = "//test/fuse/linux:readlink_test",
+)
+
+syscall_test(
+    fuse = "True",
+    test = "//test/fuse/linux:mkdir_test",
+)
+
+syscall_test(
+    fuse = "True",
+    test = "//test/fuse/linux:read_test",
+)
+
+syscall_test(
+    fuse = "True",
+    test = "//test/fuse/linux:write_test",
+)
+
+syscall_test(
+    fuse = "True",
+    test = "//test/fuse/linux:rmdir_test",
+)
+
+syscall_test(
+    fuse = "True",
+    test = "//test/fuse/linux:readdir_test",
+)
+
+syscall_test(
+    fuse = "True",
+    test = "//test/fuse/linux:create_test",
+)
+
+syscall_test(
+    fuse = "True",
+    test = "//test/fuse/linux:unlink_test",
+)
+
+syscall_test(
+    fuse = "True",
+    test = "//test/fuse/linux:setstat_test",
 )
diff --git a/test/fuse/README.md b/test/fuse/README.md
index 734c3a4e3..65add57e2 100644
--- a/test/fuse/README.md
+++ b/test/fuse/README.md
@@ -1,65 +1,114 @@
 # gVisor FUSE Test Suite
 
-This is an integration test suite for fuse(4) filesystem. It runs under both
-gVisor and Linux, and ensures compatibility between the two. This test suite is
-based on system calls test.
+This is an integration test suite for fuse(4) filesystem. It runs under gVisor
+sandbox container with VFS2 and FUSE function enabled.
 
-This document describes the framework of fuse integration test and the
-guidelines that should be followed when adding new fuse tests.
+This document describes the framework of FUSE integration test, how to use it,
+and the guidelines that should be followed when adding new testing features.
 
 ## Integration Test Framework
 
-Please refer to the figure below. `>` is entering the function, `<` is leaving
-the function, and `=` indicates sequentially entering and leaving.
+By inheriting the `FuseTest` class defined in `linux/fuse_base.h`, every test
+fixture can run in an environment with `mount_point_` mounted by a fake FUSE
+server. It creates a `socketpair(2)` to send and receive control commands and
+data between the client and the server. Because the FUSE server runs in the
+background thread, gTest cannot catch its assertion failure immediately. Thus,
+`TearDown()` function sends command to the FUSE server to check if all gTest
+assertion in the server are successful and all requests and preset responses are
+consumed.
+
+## Communication Diagram
+
+Diagram below describes how a testing thread communicates with the FUSE server
+to achieve integration test.
+
+For the following diagram, `>` means entering the function, `<` is leaving the
+function, and `=` indicates sequentially entering and leaving. Not necessarily
+follow exactly the below diagram due to the nature of a multi-threaded system,
+however, it is still helpful to know when the client waits for the server to
+complete a command and when the server awaits the next instruction.
 
 ```
- |  Client (Test Main Process)         |  Server (FUSE Daemon)
- |                                     |
- |  >TEST_F()                          |
- |    >SetUp()                         |
- |      =MountFuse()                   |
- |      >SetUpFuseServer()             |
- |        [create communication pipes] |
- |        =fork()                      |        =fork()
- |        >WaitCompleted()             |
- |          [wait for MarkDone()]      |
- |                                     |        =ConsumeFuseInit()
- |                                     |        =MarkDone()
- |        <WaitCompleted()             |
- |      <SetUpFuseServer()             |
- |    <SetUp()                         |
- |    >SetExpected()                   |
- |      [construct expected reaction]  |
- |                                     |        >FuseLoop()
- |                                     |          >ReceiveExpected()
- |                                     |            [wait data from pipe]
- |      [write data to pipe]           |
- |      [wait for MarkDone()]          |
- |                                     |            [save data to memory]
- |                                     |            =MarkDone()
- |    <SetExpected()                   |
- |                                     |          <ReceiveExpected()
- |                                     |          >read()
- |                                     |            [wait for fs operation]
- |    >[Do fs operation]               |
- |      [wait for fs response]         |
- |                                     |          <read()
- |                                     |          =CompareRequest()
- |                                     |          =write() [write fs response]
- |    <[Do fs operation]               |
- |    =[Test fs operation result]      |
- |    =[wait for MarkDone()]           |
- |                                     |          =MarkDone()
- |    >TearDown()                      |
- |      =UnmountFuse()                 |
- |    <TearDown()                      |
- |  <TEST_F()                          |
+|  Client (Testing Thread)            |  Server (FUSE Server Thread)
+|                                     |
+|  >TEST_F()                          |
+|    >SetUp()                         |
+|      =MountFuse()                   |
+|      >SetUpFuseServer()             |
+|        [create communication socket]|
+|        =fork()                      |      =fork()
+|        [wait server complete]       |
+|                                     |      =ServerConsumeFuseInit()
+|                                     |      =ServerCompleteWith()
+|      <SetUpFuseServer()             |
+|    <SetUp()                         |
+|    [testing main]                   |
+|                                     |      >ServerFuseLoop()
+|                                     |        [poll on socket and fd]
+|    >SetServerResponse()             |
+|      [write data to socket]         |
+|      [wait server complete]         |
+|                                     |        [socket event occurs]
+|                                     |        >ServerHandleCommand()
+|                                     |          >ServerReceiveResponse()
+|                                     |            [read data from socket]
+|                                     |            [save data to memory]
+|                                     |          <ServerReceiveResponse()
+|                                     |          =ServerCompleteWith()
+|    <SetServerResponse()             |
+|                                     |        <ServerHandleCommand()
+|    >[Do fs operation]               |
+|      [wait for fs response]         |
+|                                     |        [fd event occurs]
+|                                     |        >ServerProcessFuseRequest()
+|                                     |          =[read fs request]
+|                                     |          =[save fs request to memory]
+|                                     |          =[write fs response]
+|    <[Do fs operation]               |
+|                                     |        <ServerProcessFuseRequest()
+|                                     |
+|    =[Test fs operation result]      |
+|                                     |
+|    >GetServerActualRequest()        |
+|      [write data to socket]         |
+|      [wait data from server]        |
+|                                     |        [socket event occurs]
+|                                     |        >ServerHandleCommand()
+|                                     |          >ServerSendReceivedRequest()
+|                                     |            [write data to socket]
+|      [read data from socket]        |
+|      [wait server complete]         |
+|                                     |          <ServerSendReceivedRequest()
+|                                     |          =ServerCompleteWith()
+|    <GetServerActualRequest()        |
+|                                     |        <ServerHandleCommand()
+|                                     |
+|    =[Test actual request]           |
+|                                     |
+|    >TearDown()                      |
+|      ...                            |
+|      >GetServerNumUnsentResponses() |
+|        [write data to socket]       |
+|        [wait server complete]       |
+|                                     |        [socket event arrive]
+|                                     |        >ServerHandleCommand()
+|                                     |          >ServerSendData()
+|                                     |            [write data to socket]
+|                                     |          <ServerSendData()
+|                                     |          =ServerCompleteWith()
+|        [read data from socket]      |
+|        [test if all succeeded]      |
+|      <GetServerNumUnsentResponses() |
+|                                     |        <ServerHandleCommand()
+|      =UnmountFuse()                 |
+|    <TearDown()                      |
+|  <TEST_F()                          |
 ```
 
 ## Running the tests
 
-Based on syscall tests, fuse tests can run in different environments. To enable
-fuse testing environment, the test targets should be appended with `_fuse`.
+Based on syscall tests, FUSE tests generate targets only with vfs2 and fuse
+enabled. The corresponding targets end in `_fuse`.
 
 For example, to run fuse test in `stat_test.cc`:
 
@@ -77,17 +126,16 @@ $ bazel test --test_tag_filters=fuse //test/fuse/...
 
 1.  Add test targets in `BUILD` and `linux/BUILD`.
 2.  Inherit your test from `FuseTest` base class. It allows you to:
-    -   Run a fake FUSE server in background during each test setup.
-    -   Create pipes for communication and provide utility functions.
-    -   Stop FUSE server after test completes.
-3.  Customize your comparison function for request assessment in FUSE server.
-4.  Add the mapping of the size of structs if you are working on new FUSE
-    opcode.
-    -   Please update `FuseTest::GetPayloadSize()` for each new FUSE opcode.
-5.  Build the expected request-response pair of your FUSE operation.
-6.  Call `SetExpected()` function to inject the expected reaction.
-7.  Check the response and/or errors.
-8.  Finally call `WaitCompleted()` to ensure the FUSE server acts correctly.
+    -   Fork a fake FUSE server in background during each test setup.
+    -   Create a pair of sockets for communication and provide utility
+        functions.
+    -   Stop FUSE server and check if error occurs in it after test completes.
+3.  Build the expected opcode-response pairs of your FUSE operation.
+4.  Call `SetServerResponse()` to preset the next expected opcode and response.
+5.  Do real filesystem operations (FUSE is mounted at `mount_point_`).
+6.  Check FUSE response and/or errors.
+7.  Retrieve FUSE request by `GetServerActualRequest()`.
+8.  Check if the request is as expected.
 
 A few customized matchers used in syscalls test are encouraged to test the
 outcome of filesystem operations. Such as:
@@ -101,3 +149,40 @@ SyscallFailsWithErrno(...)
 
 Please refer to [test/syscalls/README.md](../syscalls/README.md) for further
 details.
+
+## Writing a new FuseTestCmd
+
+A `FuseTestCmd` is a control protocol used in the communication between the
+testing thread and the FUSE server. Such commands are sent from the testing
+thread to the FUSE server to set up, control, or inspect the behavior of the
+FUSE server in response to a sequence of FUSE requests.
+
+The lifecycle of a command contains following steps:
+
+1.  The testing thread sends a `FuseTestCmd` via socket and waits for
+    completion.
+2.  The FUSE server receives the command and does corresponding action.
+3.  (Optional) The testing thread reads data from socket.
+4.  The FUSE server sends a success indicator via socket after processing.
+5.  The testing thread gets the success signal and continues testing.
+
+The success indicator, i.e. `WaitServerComplete()`, is crucial at the end of
+each `FuseTestCmd` sent from the testing thread. Because we don't want to begin
+filesystem operation if the requests have not been completely set up. Also, to
+test FUSE interactions in a sequential manner, concurrent requests are not
+supported now.
+
+To add a new `FuseTestCmd`, one must comply with following format:
+
+1.  Add a new `FuseTestCmd` enum class item defined in `linux/fuse_base.h`
+2.  Add a `SetServerXXX()` or `GetServerXXX()` public function in `FuseTest`.
+    This is how the testing thread will call to send control message. Define how
+    many bytes you want to send along with the command and what you will expect
+    to receive. Finally it should block and wait for a success indicator from
+    the FUSE server.
+3.  Add a handler logic in the switch condition of `ServerHandleCommand()`. Use
+    `ServerSendData()` or declare a new private function such as
+    `ServerReceiveXXX()` or `ServerSendXXX()`. It is mandatory to set it private
+    since only the FUSE server (forked from `FuseTest` base class) can call it.
+    This is the server part of the specific `FuseTestCmd` and the format of the
+    data should be consistent with what the client expects in the previous step.
diff --git a/test/fuse/linux/BUILD b/test/fuse/linux/BUILD
index 4871bb531..7673252ec 100644
--- a/test/fuse/linux/BUILD
+++ b/test/fuse/linux/BUILD
@@ -11,7 +11,134 @@ cc_binary(
     srcs = ["stat_test.cc"],
     deps = [
         gtest,
+        ":fuse_fd_util",
+        "//test/util:cleanup",
+        "//test/util:fs_util",
+        "//test/util:fuse_util",
+        "//test/util:test_main",
+        "//test/util:test_util",
+    ],
+)
+
+cc_binary(
+    name = "open_test",
+    testonly = 1,
+    srcs = ["open_test.cc"],
+    deps = [
+        gtest,
         ":fuse_base",
+        "//test/util:fuse_util",
+        "//test/util:test_main",
+        "//test/util:test_util",
+    ],
+)
+
+cc_binary(
+    name = "release_test",
+    testonly = 1,
+    srcs = ["release_test.cc"],
+    deps = [
+        gtest,
+        ":fuse_base",
+        "//test/util:fuse_util",
+        "//test/util:test_main",
+        "//test/util:test_util",
+    ],
+)
+
+cc_binary(
+    name = "mknod_test",
+    testonly = 1,
+    srcs = ["mknod_test.cc"],
+    deps = [
+        gtest,
+        ":fuse_base",
+        "//test/util:fuse_util",
+        "//test/util:temp_umask",
+        "//test/util:test_main",
+        "//test/util:test_util",
+    ],
+)
+
+cc_binary(
+    name = "symlink_test",
+    testonly = 1,
+    srcs = ["symlink_test.cc"],
+    deps = [
+        gtest,
+        ":fuse_base",
+        "//test/util:fuse_util",
+        "//test/util:test_main",
+        "//test/util:test_util",
+    ],
+)
+
+cc_binary(
+    name = "readlink_test",
+    testonly = 1,
+    srcs = ["readlink_test.cc"],
+    deps = [
+        gtest,
+        ":fuse_base",
+        "//test/util:fuse_util",
+        "//test/util:test_main",
+        "//test/util:test_util",
+    ],
+)
+
+cc_binary(
+    name = "mkdir_test",
+    testonly = 1,
+    srcs = ["mkdir_test.cc"],
+    deps = [
+        gtest,
+        ":fuse_base",
+        "//test/util:fuse_util",
+        "//test/util:temp_umask",
+        "//test/util:test_main",
+        "//test/util:test_util",
+    ],
+)
+
+cc_binary(
+    name = "setstat_test",
+    testonly = 1,
+    srcs = ["setstat_test.cc"],
+    deps = [
+        gtest,
+        ":fuse_fd_util",
+        "//test/util:cleanup",
+        "//test/util:fs_util",
+        "//test/util:fuse_util",
+        "//test/util:temp_umask",
+        "//test/util:test_main",
+        "//test/util:test_util",
+    ],
+)
+
+cc_binary(
+    name = "rmdir_test",
+    testonly = 1,
+    srcs = ["rmdir_test.cc"],
+    deps = [
+        gtest,
+        ":fuse_base",
+        "//test/util:fs_util",
+        "//test/util:fuse_util",
+        "//test/util:test_main",
+        "//test/util:test_util",
+    ],
+)
+
+cc_binary(
+    name = "readdir_test",
+    testonly = 1,
+    srcs = ["readdir_test.cc"],
+    deps = [
+        gtest,
+        ":fuse_base",
+        "//test/util:fs_util",
+        "//test/util:fuse_util",
         "//test/util:test_main",
         "//test/util:test_util",
     ],
@@ -24,9 +151,80 @@ cc_library(
     hdrs = ["fuse_base.h"],
     deps = [
         gtest,
+        "//test/util:fuse_util",
         "//test/util:posix_error",
         "//test/util:temp_path",
         "//test/util:test_util",
         "@com_google_absl//absl/strings:str_format",
     ],
 )
+
+cc_library(
+    name = "fuse_fd_util",
+    testonly = 1,
+    srcs = ["fuse_fd_util.cc"],
+    hdrs = ["fuse_fd_util.h"],
+    deps = [
+        gtest,
+        ":fuse_base",
+        "//test/util:cleanup",
+        "//test/util:file_descriptor",
+        "//test/util:fuse_util",
+        "//test/util:posix_error",
+    ],
+)
+
+cc_binary(
+    name = "read_test",
+    testonly = 1,
+    srcs = ["read_test.cc"],
+    deps = [
+        gtest,
+        ":fuse_base",
+        "//test/util:fuse_util",
+        "//test/util:test_main",
+        "//test/util:test_util",
+    ],
+)
+
+cc_binary(
+    name = "write_test",
+    testonly = 1,
+    srcs = ["write_test.cc"],
+    deps = [
+        gtest,
+        ":fuse_base",
+        "//test/util:fuse_util",
+        "//test/util:test_main",
+        "//test/util:test_util",
+    ],
+)
+
+cc_binary(
+    name = "create_test",
+    testonly = 1,
+    srcs = ["create_test.cc"],
+    deps = [
+        gtest,
+        ":fuse_base",
+        "//test/util:fs_util",
+        "//test/util:fuse_util",
+        "//test/util:temp_umask",
+        "//test/util:test_main",
+        "//test/util:test_util",
+    ],
+)
+
+cc_binary(
+    name = "unlink_test",
+    testonly = 1,
+    srcs = ["unlink_test.cc"],
+    deps = [
+        gtest,
+        ":fuse_base",
+        "//test/util:fuse_util",
+        "//test/util:temp_umask",
+        "//test/util:test_main",
+        "//test/util:test_util",
+    ],
+)
diff --git a/test/fuse/linux/create_test.cc b/test/fuse/linux/create_test.cc
new file mode 100644
index 000000000..9a0219a58
--- /dev/null
+++ b/test/fuse/linux/create_test.cc
@@ -0,0 +1,128 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fuse.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <string>
+
+#include "gtest/gtest.h"
+#include "test/fuse/linux/fuse_base.h"
+#include "test/util/fs_util.h"
+#include "test/util/fuse_util.h"
+#include "test/util/temp_umask.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+class CreateTest : public FuseTest {
+ protected:
+  const std::string test_file_name_ = "test_file";
+  const mode_t mode = S_IFREG | S_IRWXU | S_IRWXG | S_IRWXO;
+};
+
+TEST_F(CreateTest, CreateFile) {
+  const std::string test_file_path =
+      JoinPath(mount_point_.path().c_str(), test_file_name_);
+
+  // Ensure the file doesn't exist.
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header),
+      .error = -ENOENT,
+  };
+  auto iov_out = FuseGenerateIovecs(out_header);
+  SetServerResponse(FUSE_LOOKUP, iov_out);
+
+  // creat(2) is equal to open(2) with open_flags O_CREAT | O_WRONLY | O_TRUNC.
+  const mode_t new_mask = S_IWGRP | S_IWOTH;
+  const int open_flags = O_CREAT | O_WRONLY | O_TRUNC;
+  out_header.error = 0;
+  out_header.len = sizeof(struct fuse_out_header) +
+                   sizeof(struct fuse_entry_out) + sizeof(struct fuse_open_out);
+  struct fuse_entry_out entry_payload = DefaultEntryOut(mode & ~new_mask, 2);
+  struct fuse_open_out out_payload = {
+      .fh = 1,
+      .open_flags = open_flags,
+  };
+  iov_out = FuseGenerateIovecs(out_header, entry_payload, out_payload);
+  SetServerResponse(FUSE_CREATE, iov_out);
+
+  // kernfs generates a successive FUSE_OPEN after the file is created. Linux's
+  // fuse kernel module will not send this FUSE_OPEN after creat(2).
+  out_header.len =
+      sizeof(struct fuse_out_header) + sizeof(struct fuse_open_out);
+  iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_OPEN, iov_out);
+
+  int fd;
+  TempUmask mask(new_mask);
+  EXPECT_THAT(fd = creat(test_file_path.c_str(), mode), SyscallSucceeds());
+  EXPECT_THAT(fcntl(fd, F_GETFL),
+              SyscallSucceedsWithValue(open_flags & O_ACCMODE));
+
+  struct fuse_in_header in_header;
+  struct fuse_create_in in_payload;
+  std::vector<char> name(test_file_name_.size() + 1);
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload, name);
+
+  // Skip the request of FUSE_LOOKUP.
+  SkipServerActualRequest();
+
+  // Get the first FUSE_CREATE.
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_header.len, sizeof(in_header) + sizeof(in_payload) +
+                               test_file_name_.size() + 1);
+  EXPECT_EQ(in_header.opcode, FUSE_CREATE);
+  EXPECT_EQ(in_payload.flags, open_flags);
+  EXPECT_EQ(in_payload.mode, mode & ~new_mask);
+  EXPECT_EQ(in_payload.umask, new_mask);
+  EXPECT_EQ(std::string(name.data()), test_file_name_);
+
+  // Get the successive FUSE_OPEN.
+  struct fuse_open_in in_payload_open;
+  iov_in = FuseGenerateIovecs(in_header, in_payload_open);
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_header.len, sizeof(in_header) + sizeof(in_payload_open));
+  EXPECT_EQ(in_header.opcode, FUSE_OPEN);
+  EXPECT_EQ(in_payload_open.flags, open_flags & O_ACCMODE);
+
+  EXPECT_THAT(close(fd), SyscallSucceeds());
+  // Skip the FUSE_RELEASE.
+  SkipServerActualRequest();
+}
+
+TEST_F(CreateTest, CreateFileAlreadyExists) {
+  const std::string test_file_path =
+      JoinPath(mount_point_.path().c_str(), test_file_name_);
+
+  const int open_flags = O_CREAT | O_EXCL;
+
+  SetServerInodeLookup(test_file_name_);
+
+  EXPECT_THAT(open(test_file_path.c_str(), mode, open_flags),
+              SyscallFailsWithErrno(EEXIST));
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor
diff --git a/test/fuse/linux/fuse_base.cc b/test/fuse/linux/fuse_base.cc
index 9c3124472..5b45804e1 100644
--- a/test/fuse/linux/fuse_base.cc
+++ b/test/fuse/linux/fuse_base.cc
@@ -16,17 +16,17 @@
 
 #include <fcntl.h>
 #include <linux/fuse.h>
-#include <string.h>
+#include <poll.h>
 #include <sys/mount.h>
+#include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/uio.h>
 #include <unistd.h>
 
-#include <iostream>
-
 #include "gtest/gtest.h"
 #include "absl/strings/str_format.h"
+#include "test/util/fuse_util.h"
 #include "test/util/posix_error.h"
 #include "test/util/temp_path.h"
 #include "test/util/test_util.h"
@@ -39,49 +39,123 @@ void FuseTest::SetUp() {
   SetUpFuseServer();
 }
 
-void FuseTest::TearDown() { UnmountFuse(); }
-
-// Since CompareRequest is running in background thread, gTest assertions and
-// expectations won't directly reflect the test result. However, the FUSE
-// background server still connects to the same standard I/O as testing main
-// thread. So EXPECT_XX can still be used to show different results. To
-// ensure failed testing result is observable, return false and the result
-// will be sent to test main thread via pipe.
-bool FuseTest::CompareRequest(void* expected_mem, size_t expected_len,
-                              void* real_mem, size_t real_len) {
-  if (expected_len != real_len) return false;
-  return memcmp(expected_mem, real_mem, expected_len) == 0;
+void FuseTest::TearDown() {
+  EXPECT_EQ(GetServerNumUnconsumedRequests(), 0);
+  EXPECT_EQ(GetServerNumUnsentResponses(), 0);
+  UnmountFuse();
 }
 
-// SetExpected is called by the testing main thread to set expected request-
-// response pair of a single FUSE operation.
-void FuseTest::SetExpected(struct iovec* iov_in, int iov_in_cnt,
-                           struct iovec* iov_out, int iov_out_cnt) {
-  EXPECT_THAT(RetryEINTR(writev)(set_expected_[1], iov_in, iov_in_cnt),
-              SyscallSucceedsWithValue(::testing::Gt(0)));
-  WaitCompleted();
+// Sends 3 parts of data to the FUSE server:
+//   1. The `kSetResponse` command
+//   2. The expected opcode
+//   3. The fake FUSE response
+// Then waits for the FUSE server to notify its completion.
+void FuseTest::SetServerResponse(uint32_t opcode,
+                                 std::vector<struct iovec>& iovecs) {
+  uint32_t cmd = static_cast<uint32_t>(FuseTestCmd::kSetResponse);
+  EXPECT_THAT(RetryEINTR(write)(sock_[0], &cmd, sizeof(cmd)),
+              SyscallSucceedsWithValue(sizeof(cmd)));
+
+  EXPECT_THAT(RetryEINTR(write)(sock_[0], &opcode, sizeof(opcode)),
+              SyscallSucceedsWithValue(sizeof(opcode)));
 
-  EXPECT_THAT(RetryEINTR(writev)(set_expected_[1], iov_out, iov_out_cnt),
-              SyscallSucceedsWithValue(::testing::Gt(0)));
-  WaitCompleted();
+  EXPECT_THAT(RetryEINTR(writev)(sock_[0], iovecs.data(), iovecs.size()),
+              SyscallSucceeds());
+
+  WaitServerComplete();
 }
 
-// WaitCompleted waits for the FUSE server to finish its job and check if it
+// Waits for the FUSE server to finish its blocking job and check if it
 // completes without errors.
-void FuseTest::WaitCompleted() {
-  char success;
-  EXPECT_THAT(RetryEINTR(read)(done_[0], &success, sizeof(success)),
-              SyscallSucceedsWithValue(1));
+void FuseTest::WaitServerComplete() {
+  uint32_t success;
+  EXPECT_THAT(RetryEINTR(read)(sock_[0], &success, sizeof(success)),
+              SyscallSucceedsWithValue(sizeof(success)));
+  ASSERT_EQ(success, 1);
+}
+
+// Sends the `kGetRequest` command to the FUSE server, then reads the next
+// request into iovec struct. The order of calling this function should be
+// the same as the one of SetServerResponse().
+void FuseTest::GetServerActualRequest(std::vector<struct iovec>& iovecs) {
+  uint32_t cmd = static_cast<uint32_t>(FuseTestCmd::kGetRequest);
+  EXPECT_THAT(RetryEINTR(write)(sock_[0], &cmd, sizeof(cmd)),
+              SyscallSucceedsWithValue(sizeof(cmd)));
+
+  EXPECT_THAT(RetryEINTR(readv)(sock_[0], iovecs.data(), iovecs.size()),
+              SyscallSucceeds());
+
+  WaitServerComplete();
+}
+
+// Sends a FuseTestCmd command to the FUSE server, reads from the socket, and
+// returns the corresponding data.
+uint32_t FuseTest::GetServerData(uint32_t cmd) {
+  uint32_t data;
+  EXPECT_THAT(RetryEINTR(write)(sock_[0], &cmd, sizeof(cmd)),
+              SyscallSucceedsWithValue(sizeof(cmd)));
+
+  EXPECT_THAT(RetryEINTR(read)(sock_[0], &data, sizeof(data)),
+              SyscallSucceedsWithValue(sizeof(data)));
+
+  WaitServerComplete();
+  return data;
+}
+
+uint32_t FuseTest::GetServerNumUnconsumedRequests() {
+  return GetServerData(
+      static_cast<uint32_t>(FuseTestCmd::kGetNumUnconsumedRequests));
+}
+
+uint32_t FuseTest::GetServerNumUnsentResponses() {
+  return GetServerData(
+      static_cast<uint32_t>(FuseTestCmd::kGetNumUnsentResponses));
+}
+
+uint32_t FuseTest::GetServerTotalReceivedBytes() {
+  return GetServerData(
+      static_cast<uint32_t>(FuseTestCmd::kGetTotalReceivedBytes));
+}
+
+// Sends the `kSkipRequest` command to the FUSE server, which would skip
+// current stored request data.
+void FuseTest::SkipServerActualRequest() {
+  uint32_t cmd = static_cast<uint32_t>(FuseTestCmd::kSkipRequest);
+  EXPECT_THAT(RetryEINTR(write)(sock_[0], &cmd, sizeof(cmd)),
+              SyscallSucceedsWithValue(sizeof(cmd)));
+
+  WaitServerComplete();
 }
 
-void FuseTest::MountFuse() {
+// Sends the `kSetInodeLookup` command, expected mode, and the path of the
+// inode to create under the mount point.
+void FuseTest::SetServerInodeLookup(const std::string& path, mode_t mode,
+                                    uint64_t size) {
+  uint32_t cmd = static_cast<uint32_t>(FuseTestCmd::kSetInodeLookup);
+  EXPECT_THAT(RetryEINTR(write)(sock_[0], &cmd, sizeof(cmd)),
+              SyscallSucceedsWithValue(sizeof(cmd)));
+
+  EXPECT_THAT(RetryEINTR(write)(sock_[0], &mode, sizeof(mode)),
+              SyscallSucceedsWithValue(sizeof(mode)));
+
+  EXPECT_THAT(RetryEINTR(write)(sock_[0], &size, sizeof(size)),
+              SyscallSucceedsWithValue(sizeof(size)));
+
+  // Pad 1 byte for null-terminate c-string.
+  EXPECT_THAT(RetryEINTR(write)(sock_[0], path.c_str(), path.size() + 1),
+              SyscallSucceedsWithValue(path.size() + 1));
+
+  WaitServerComplete();
+}
+
+void FuseTest::MountFuse(const char* mountOpts) {
   EXPECT_THAT(dev_fd_ = open("/dev/fuse", O_RDWR), SyscallSucceeds());
 
-  std::string mount_opts = absl::StrFormat("fd=%d,%s", dev_fd_, kMountOpts);
+  std::string mount_opts = absl::StrFormat("fd=%d,%s", dev_fd_, mountOpts);
   mount_point_ = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
   EXPECT_THAT(mount("fuse", mount_point_.path().c_str(), "fuse",
                     MS_NODEV | MS_NOSUID, mount_opts.c_str()),
-              SyscallSucceedsWithValue(0));
+              SyscallSucceeds());
 }
 
 void FuseTest::UnmountFuse() {
@@ -89,13 +163,13 @@ void FuseTest::UnmountFuse() {
   // TODO(gvisor.dev/issue/3330): ensure the process is terminated successfully.
 }
 
-// ConsumeFuseInit consumes the first FUSE request and returns the
-// corresponding PosixError.
-PosixError FuseTest::ConsumeFuseInit() {
+// Consumes the first FUSE request and returns the corresponding PosixError.
+PosixError FuseTest::ServerConsumeFuseInit(
+    const struct fuse_init_out* out_payload) {
+  std::vector<char> buf(FUSE_MIN_READ_BUFFER);
   RETURN_ERROR_IF_SYSCALL_FAIL(
-      RetryEINTR(read)(dev_fd_, buf_.data(), buf_.size()));
+      RetryEINTR(read)(dev_fd_, buf.data(), buf.size()));
 
-  struct iovec iov_out[2];
   struct fuse_out_header out_header = {
       .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_init_out),
       .error = 0,
@@ -103,72 +177,74 @@ PosixError FuseTest::ConsumeFuseInit() {
   };
   // Returns a fake fuse_init_out with 7.0 version to avoid ECONNREFUSED
   // error in the initialization of FUSE connection.
-  struct fuse_init_out out_payload = {
-      .major = 7,
-  };
-  iov_out[0].iov_len = sizeof(out_header);
-  iov_out[0].iov_base = &out_header;
-  iov_out[1].iov_len = sizeof(out_payload);
-  iov_out[1].iov_base = &out_payload;
+  auto iov_out = FuseGenerateIovecs(
+      out_header, *const_cast<struct fuse_init_out*>(out_payload));
 
-  RETURN_ERROR_IF_SYSCALL_FAIL(RetryEINTR(writev)(dev_fd_, iov_out, 2));
+  RETURN_ERROR_IF_SYSCALL_FAIL(
+      RetryEINTR(writev)(dev_fd_, iov_out.data(), iov_out.size()));
   return NoError();
 }
 
-// ReceiveExpected reads 1 pair of expected fuse request-response `iovec`s
-// from pipe and save them into member variables of this testing instance.
-void FuseTest::ReceiveExpected() {
-  // Set expected fuse_in request.
-  EXPECT_THAT(len_in_ = RetryEINTR(read)(set_expected_[0], mem_in_.data(),
-                                         mem_in_.size()),
-              SyscallSucceedsWithValue(::testing::Gt(0)));
-  MarkDone(len_in_ > 0);
+// Reads 1 expected opcode and a fake response from socket and save them into
+// the serial buffer of this testing instance.
+void FuseTest::ServerReceiveResponse() {
+  ssize_t len;
+  uint32_t opcode;
+  std::vector<char> buf(FUSE_MIN_READ_BUFFER);
+  EXPECT_THAT(RetryEINTR(read)(sock_[1], &opcode, sizeof(opcode)),
+              SyscallSucceedsWithValue(sizeof(opcode)));
 
-  // Set expected fuse_out response.
-  EXPECT_THAT(len_out_ = RetryEINTR(read)(set_expected_[0], mem_out_.data(),
-                                          mem_out_.size()),
-              SyscallSucceedsWithValue(::testing::Gt(0)));
-  MarkDone(len_out_ > 0);
+  EXPECT_THAT(len = RetryEINTR(read)(sock_[1], buf.data(), buf.size()),
+              SyscallSucceeds());
+
+  responses_.AddMemBlock(opcode, buf.data(), len);
 }
 
-// MarkDone writes 1 byte of success indicator through pipe.
-void FuseTest::MarkDone(bool success) {
-  char data = success ? 1 : 0;
-  EXPECT_THAT(RetryEINTR(write)(done_[1], &data, sizeof(data)),
-              SyscallSucceedsWithValue(1));
+// Writes 1 byte of success indicator through socket.
+void FuseTest::ServerCompleteWith(bool success) {
+  uint32_t data = success ? 1 : 0;
+  ServerSendData(data);
 }
 
-// FuseLoop is the implementation of the fake FUSE server. Read from /dev/fuse,
-// compare the request by CompareRequest (use derived function if specified),
-// and write the expected response to /dev/fuse.
-void FuseTest::FuseLoop() {
-  bool success = true;
-  ssize_t len = 0;
+// ServerFuseLoop is the implementation of the fake FUSE server. Monitors 2
+// file descriptors: /dev/fuse and sock_[1]. Events from /dev/fuse are FUSE
+// requests and events from sock_[1] are FUSE testing commands, leading by
+// a FuseTestCmd data to indicate the command.
+void FuseTest::ServerFuseLoop() {
+  const int nfds = 2;
+  struct pollfd fds[nfds] = {
+      {
+          .fd = dev_fd_,
+          .events = POLL_IN | POLLHUP | POLLERR | POLLNVAL,
+      },
+      {
+          .fd = sock_[1],
+          .events = POLL_IN | POLLHUP | POLLERR | POLLNVAL,
+      },
+  };
+
   while (true) {
-    ReceiveExpected();
+    ASSERT_THAT(poll(fds, nfds, -1), SyscallSucceeds());
 
-    EXPECT_THAT(len = RetryEINTR(read)(dev_fd_, buf_.data(), buf_.size()),
-                SyscallSucceedsWithValue(len_in_));
-    if (len != len_in_) success = false;
+    for (int fd_idx = 0; fd_idx < nfds; ++fd_idx) {
+      if (fds[fd_idx].revents == 0) continue;
 
-    if (!CompareRequest(buf_.data(), len_in_, mem_in_.data(), len_in_)) {
-      std::cerr << "the FUSE request is not expected" << std::endl;
-      success = false;
+      ASSERT_EQ(fds[fd_idx].revents, POLL_IN);
+      if (fds[fd_idx].fd == sock_[1]) {
+        ServerHandleCommand();
+      } else if (fds[fd_idx].fd == dev_fd_) {
+        ServerProcessFuseRequest();
+      }
     }
-
-    EXPECT_THAT(len = RetryEINTR(write)(dev_fd_, mem_out_.data(), len_out_),
-                SyscallSucceedsWithValue(len_out_));
-    if (len != len_out_) success = false;
-    MarkDone(success);
   }
 }
 
-// SetUpFuseServer creates 2 pipes. First is for testing client to send the
-// expected request-response pair, and the other acts as a checkpoint for the
-// FUSE server to notify the client that it can proceed.
-void FuseTest::SetUpFuseServer() {
-  ASSERT_THAT(pipe(set_expected_), SyscallSucceedsWithValue(0));
-  ASSERT_THAT(pipe(done_), SyscallSucceedsWithValue(0));
+// SetUpFuseServer creates 1 socketpair and fork the process. The parent thread
+// becomes testing thread and the child thread becomes the FUSE server running
+// in background. These 2 threads are connected via socketpair. sock_[0] is
+// opened in testing thread and sock_[1] is opened in the FUSE server.
+void FuseTest::SetUpFuseServer(const struct fuse_init_out* payload) {
+  ASSERT_THAT(socketpair(AF_UNIX, SOCK_STREAM, 0, sock_), SyscallSucceeds());
 
   switch (fork()) {
     case -1:
@@ -177,31 +253,194 @@ void FuseTest::SetUpFuseServer() {
     case 0:
       break;
     default:
-      ASSERT_THAT(close(set_expected_[0]), SyscallSucceedsWithValue(0));
-      ASSERT_THAT(close(done_[1]), SyscallSucceedsWithValue(0));
-      WaitCompleted();
+      ASSERT_THAT(close(sock_[1]), SyscallSucceeds());
+      WaitServerComplete();
       return;
   }
 
-  ASSERT_THAT(close(set_expected_[1]), SyscallSucceedsWithValue(0));
-  ASSERT_THAT(close(done_[0]), SyscallSucceedsWithValue(0));
-
-  MarkDone(ConsumeFuseInit().ok());
-
-  FuseLoop();
+  // Begin child thread, i.e. the FUSE server.
+  ASSERT_THAT(close(sock_[0]), SyscallSucceeds());
+  ServerCompleteWith(ServerConsumeFuseInit(payload).ok());
+  ServerFuseLoop();
   _exit(0);
 }
 
-// GetPayloadSize is a helper function to get the number of bytes of a
-// specific FUSE operation struct.
-size_t FuseTest::GetPayloadSize(uint32_t opcode, bool in) {
-  switch (opcode) {
-    case FUSE_INIT:
-      return in ? sizeof(struct fuse_init_in) : sizeof(struct fuse_init_out);
+void FuseTest::ServerSendData(uint32_t data) {
+  EXPECT_THAT(RetryEINTR(write)(sock_[1], &data, sizeof(data)),
+              SyscallSucceedsWithValue(sizeof(data)));
+}
+
+// Reads FuseTestCmd sent from testing thread and routes to correct handler.
+// Since each command should be a blocking operation, a `ServerCompleteWith()`
+// is required after the switch keyword.
+void FuseTest::ServerHandleCommand() {
+  uint32_t cmd;
+  EXPECT_THAT(RetryEINTR(read)(sock_[1], &cmd, sizeof(cmd)),
+              SyscallSucceedsWithValue(sizeof(cmd)));
+
+  switch (static_cast<FuseTestCmd>(cmd)) {
+    case FuseTestCmd::kSetResponse:
+      ServerReceiveResponse();
+      break;
+    case FuseTestCmd::kSetInodeLookup:
+      ServerReceiveInodeLookup();
+      break;
+    case FuseTestCmd::kGetRequest:
+      ServerSendReceivedRequest();
+      break;
+    case FuseTestCmd::kGetTotalReceivedBytes:
+      ServerSendData(static_cast<uint32_t>(requests_.UsedBytes()));
+      break;
+    case FuseTestCmd::kGetNumUnconsumedRequests:
+      ServerSendData(static_cast<uint32_t>(requests_.RemainingBlocks()));
+      break;
+    case FuseTestCmd::kGetNumUnsentResponses:
+      ServerSendData(static_cast<uint32_t>(responses_.RemainingBlocks()));
+      break;
+    case FuseTestCmd::kSkipRequest:
+      ServerSkipReceivedRequest();
+      break;
     default:
+      FAIL() << "Unknown FuseTestCmd " << cmd;
       break;
   }
-  return 0;
+
+  ServerCompleteWith(!HasFailure());
+}
+
+// Reads the expected file mode and the path of one file. Crafts a basic
+// `fuse_entry_out` memory block and inserts into a map for future use.
+// The FUSE server will always return this response if a FUSE_LOOKUP
+// request with this specific path comes in.
+void FuseTest::ServerReceiveInodeLookup() {
+  mode_t mode;
+  uint64_t size;
+  std::vector<char> buf(FUSE_MIN_READ_BUFFER);
+
+  EXPECT_THAT(RetryEINTR(read)(sock_[1], &mode, sizeof(mode)),
+              SyscallSucceedsWithValue(sizeof(mode)));
+
+  EXPECT_THAT(RetryEINTR(read)(sock_[1], &size, sizeof(size)),
+              SyscallSucceedsWithValue(sizeof(size)));
+
+  EXPECT_THAT(RetryEINTR(read)(sock_[1], buf.data(), buf.size()),
+              SyscallSucceeds());
+
+  std::string path(buf.data());
+
+  uint32_t out_len =
+      sizeof(struct fuse_out_header) + sizeof(struct fuse_entry_out);
+  struct fuse_out_header out_header = {
+      .len = out_len,
+      .error = 0,
+  };
+  struct fuse_entry_out out_payload = DefaultEntryOut(mode, nodeid_);
+  // Since this is only used in test, nodeid_ is simply increased by 1 to
+  // comply with the unqiueness of different path.
+  ++nodeid_;
+
+  // Set the size.
+  out_payload.attr.size = size;
+
+  memcpy(buf.data(), &out_header, sizeof(out_header));
+  memcpy(buf.data() + sizeof(out_header), &out_payload, sizeof(out_payload));
+  lookups_.AddMemBlock(FUSE_LOOKUP, buf.data(), out_len);
+  lookup_map_[path] = lookups_.Next();
+}
+
+// Sends the received request pointed by current cursor and advances cursor.
+void FuseTest::ServerSendReceivedRequest() {
+  if (requests_.End()) {
+    FAIL() << "No more received request.";
+    return;
+  }
+  auto mem_block = requests_.Next();
+  EXPECT_THAT(
+      RetryEINTR(write)(sock_[1], requests_.DataAtOffset(mem_block.offset),
+                        mem_block.len),
+      SyscallSucceedsWithValue(mem_block.len));
+}
+
+// Skip the request pointed by current cursor.
+void FuseTest::ServerSkipReceivedRequest() {
+  if (requests_.End()) {
+    FAIL() << "No more received request.";
+    return;
+  }
+  requests_.Next();
+}
+
+// Handles FUSE request. Reads request from /dev/fuse, checks if it has the
+// same opcode as expected, and responds with the saved fake FUSE response.
+// The FUSE request is copied to the serial buffer and can be retrieved one-
+// by-one by calling GetServerActualRequest from testing thread.
+void FuseTest::ServerProcessFuseRequest() {
+  ssize_t len;
+  std::vector<char> buf(FUSE_MIN_READ_BUFFER);
+
+  // Read FUSE request.
+  EXPECT_THAT(len = RetryEINTR(read)(dev_fd_, buf.data(), buf.size()),
+              SyscallSucceeds());
+  fuse_in_header* in_header = reinterpret_cast<fuse_in_header*>(buf.data());
+
+  // Check if this is a preset FUSE_LOOKUP path.
+  if (in_header->opcode == FUSE_LOOKUP) {
+    std::string path(buf.data() + sizeof(struct fuse_in_header));
+    auto it = lookup_map_.find(path);
+    if (it != lookup_map_.end()) {
+      // Matches a preset path. Reply with fake data and skip saving the
+      // request.
+      ServerRespondFuseSuccess(lookups_, it->second, in_header->unique);
+      return;
+    }
+  }
+
+  requests_.AddMemBlock(in_header->opcode, buf.data(), len);
+
+  if (in_header->opcode == FUSE_RELEASE || in_header->opcode == FUSE_RELEASEDIR)
+    return;
+  // Check if there is a corresponding response.
+  if (responses_.End()) {
+    GTEST_NONFATAL_FAILURE_("No more FUSE response is expected");
+    ServerRespondFuseError(in_header->unique);
+    return;
+  }
+  auto mem_block = responses_.Next();
+  if (in_header->opcode != mem_block.opcode) {
+    std::string message = absl::StrFormat("Expect opcode %d but got %d",
+                                          mem_block.opcode, in_header->opcode);
+    GTEST_NONFATAL_FAILURE_(message.c_str());
+    // We won't get correct response if opcode is not expected. Send error
+    // response here to avoid wrong parsing by VFS.
+    ServerRespondFuseError(in_header->unique);
+    return;
+  }
+
+  // Write FUSE response.
+  ServerRespondFuseSuccess(responses_, mem_block, in_header->unique);
+}
+
+void FuseTest::ServerRespondFuseSuccess(FuseMemBuffer& mem_buf,
+                                        const FuseMemBlock& block,
+                                        uint64_t unique) {
+  fuse_out_header* out_header =
+      reinterpret_cast<fuse_out_header*>(mem_buf.DataAtOffset(block.offset));
+
+  // Patch `unique` in fuse_out_header to avoid EINVAL caused by responding
+  // with an unknown `unique`.
+  out_header->unique = unique;
+  EXPECT_THAT(RetryEINTR(write)(dev_fd_, out_header, block.len),
+              SyscallSucceedsWithValue(block.len));
+}
+
+void FuseTest::ServerRespondFuseError(uint64_t unique) {
+  fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header),
+      .error = ENOSYS,
+      .unique = unique,
+  };
+  EXPECT_THAT(RetryEINTR(write)(dev_fd_, &out_header, sizeof(out_header)),
+              SyscallSucceedsWithValue(sizeof(out_header)));
 }
 
 }  // namespace testing
diff --git a/test/fuse/linux/fuse_base.h b/test/fuse/linux/fuse_base.h
index 3a2f255a9..6ad296ca2 100644
--- a/test/fuse/linux/fuse_base.h
+++ b/test/fuse/linux/fuse_base.h
@@ -16,8 +16,12 @@
 #define GVISOR_TEST_FUSE_FUSE_BASE_H_
 
 #include <linux/fuse.h>
+#include <string.h>
+#include <sys/stat.h>
 #include <sys/uio.h>
 
+#include <iostream>
+#include <unordered_map>
 #include <vector>
 
 #include "gtest/gtest.h"
@@ -29,68 +33,216 @@ namespace testing {
 
 constexpr char kMountOpts[] = "rootmode=755,user_id=0,group_id=0";
 
-class FuseTest : public ::testing::Test {
+constexpr struct fuse_init_out kDefaultFUSEInitOutPayload = {.major = 7};
+
+// Internal commands used to communicate between testing thread and the FUSE
+// server. See test/fuse/README.md for further detail.
+enum class FuseTestCmd {
+  kSetResponse = 0,
+  kSetInodeLookup,
+  kGetRequest,
+  kGetNumUnconsumedRequests,
+  kGetNumUnsentResponses,
+  kGetTotalReceivedBytes,
+  kSkipRequest,
+};
+
+// Holds the information of a memory block in a serial buffer.
+struct FuseMemBlock {
+  uint32_t opcode;
+  size_t offset;
+  size_t len;
+};
+
+// A wrapper of a simple serial buffer that can be used with read(2) and
+// write(2). Contains a cursor to indicate accessing. This class is not thread-
+// safe and can only be used in single-thread version.
+class FuseMemBuffer {
  public:
-  FuseTest() {
-    buf_.resize(FUSE_MIN_READ_BUFFER);
-    mem_in_.resize(FUSE_MIN_READ_BUFFER);
-    mem_out_.resize(FUSE_MIN_READ_BUFFER);
+  FuseMemBuffer() : cursor_(0) {
+    // To read from /dev/fuse, a buffer needs at least FUSE_MIN_READ_BUFFER
+    // bytes to avoid EINVAL. FuseMemBuffer holds memory that can accommodate
+    // a sequence of FUSE request/response, so it is initiated with double
+    // minimal requirement.
+    mem_.resize(FUSE_MIN_READ_BUFFER * 2);
   }
-  void SetUp() override;
-  void TearDown() override;
 
-  // CompareRequest is used by the FUSE server and should be implemented to
-  // compare different FUSE operations. It compares the actual FUSE input
-  // request with the expected one set by `SetExpected()`.
-  virtual bool CompareRequest(void* expected_mem, size_t expected_len,
-                              void* real_mem, size_t real_len);
+  // Returns whether there is no memory block.
+  bool Empty() { return blocks_.empty(); }
+
+  // Returns if there is no more remaining memory blocks.
+  bool End() { return cursor_ == blocks_.size(); }
+
+  // Returns how many bytes that have been received.
+  size_t UsedBytes() {
+    return Empty() ? 0 : blocks_.back().offset + blocks_.back().len;
+  }
+
+  // Returns the available bytes remains in the serial buffer.
+  size_t AvailBytes() { return mem_.size() - UsedBytes(); }
+
+  // Appends a memory block information that starts at the tail of the serial
+  // buffer. /dev/fuse requires at least FUSE_MIN_READ_BUFFER bytes to read, or
+  // it will issue EINVAL. If it is not enough, just double the buffer length.
+  void AddMemBlock(uint32_t opcode, void* data, size_t len) {
+    if (AvailBytes() < FUSE_MIN_READ_BUFFER) {
+      mem_.resize(mem_.size() << 1);
+    }
+    size_t offset = UsedBytes();
+    memcpy(mem_.data() + offset, data, len);
+    blocks_.push_back(FuseMemBlock{opcode, offset, len});
+  }
+
+  // Returns the memory address at a specific offset. Used with read(2) or
+  // write(2).
+  char* DataAtOffset(size_t offset) { return mem_.data() + offset; }
+
+  // Returns current memory block pointed by the cursor and increase by 1.
+  FuseMemBlock Next() {
+    if (End()) {
+      std::cerr << "Buffer is already exhausted." << std::endl;
+      return FuseMemBlock{};
+    }
+    return blocks_[cursor_++];
+  }
+
+  // Returns the number of the blocks that has not been requested.
+  size_t RemainingBlocks() { return blocks_.size() - cursor_; }
+
+ private:
+  size_t cursor_;
+  std::vector<FuseMemBlock> blocks_;
+  std::vector<char> mem_;
+};
 
-  // SetExpected is called by the testing main thread. Writes a request-
-  // response pair into FUSE server's member variables via pipe.
-  void SetExpected(struct iovec* iov_in, int iov_in_cnt, struct iovec* iov_out,
-                   int iov_out_cnt);
+// FuseTest base class is useful in FUSE integration test. Inherit this class
+// to automatically set up a fake FUSE server and use the member functions
+// to manipulate with it. Refer to test/fuse/README.md for detailed explanation.
+class FuseTest : public ::testing::Test {
+ public:
+  // nodeid_ is the ID of a fake inode. We starts from 2 since 1 is occupied by
+  // the mount point.
+  FuseTest() : nodeid_(2) {}
+  void SetUp() override;
+  void TearDown() override;
 
-  // WaitCompleted waits for FUSE server to complete its processing. It
-  // complains if the FUSE server responds failure during tests.
-  void WaitCompleted();
+  // Called by the testing thread to set up a fake response for an expected
+  // opcode via socket. This can be used multiple times to define a sequence of
+  // expected FUSE reactions.
+  void SetServerResponse(uint32_t opcode, std::vector<struct iovec>& iovecs);
+
+  // Called by the testing thread to install a fake path under the mount point.
+  // e.g. a file under /mnt/dir/file and moint point is /mnt, then it will look
+  // up "dir/file" in this case.
+  //
+  // It sets a fixed response to the FUSE_LOOKUP requests issued with this
+  // path, pretending there is an inode and avoid ENOENT when testing. If mode
+  // is not given, it creates a regular file with mode 0600.
+  void SetServerInodeLookup(const std::string& path,
+                            mode_t mode = S_IFREG | S_IRUSR | S_IWUSR,
+                            uint64_t size = 512);
+
+  // Called by the testing thread to ask the FUSE server for its next received
+  // FUSE request. Be sure to use the corresponding struct of iovec to receive
+  // data from server.
+  void GetServerActualRequest(std::vector<struct iovec>& iovecs);
+
+  // Called by the testing thread to query the number of unconsumed requests in
+  // the requests_ serial buffer of the FUSE server. TearDown() ensures all
+  // FUSE requests received by the FUSE server were consumed by the testing
+  // thread.
+  uint32_t GetServerNumUnconsumedRequests();
+
+  // Called by the testing thread to query the number of unsent responses in
+  // the responses_ serial buffer of the FUSE server. TearDown() ensures all
+  // preset FUSE responses were sent out by the FUSE server.
+  uint32_t GetServerNumUnsentResponses();
+
+  // Called by the testing thread to ask the FUSE server for its total received
+  // bytes from /dev/fuse.
+  uint32_t GetServerTotalReceivedBytes();
+
+  // Called by the testing thread to ask the FUSE server to skip stored
+  // request data.
+  void SkipServerActualRequest();
 
  protected:
   TempPath mount_point_;
 
- private:
-  void MountFuse();
+  // Opens /dev/fuse and inherit the file descriptor for the FUSE server.
+  void MountFuse(const char* mountOpts = kMountOpts);
+
+  // Creates a socketpair for communication and forks FUSE server.
+  void SetUpFuseServer(
+      const struct fuse_init_out* payload = &kDefaultFUSEInitOutPayload);
+
+  // Unmounts the mountpoint of the FUSE server.
   void UnmountFuse();
 
-  // ConsumeFuseInit is only used during FUSE server setup.
-  PosixError ConsumeFuseInit();
+ private:
+  // Sends a FuseTestCmd and gets a uint32_t data from the FUSE server.
+  inline uint32_t GetServerData(uint32_t cmd);
+
+  // Waits for FUSE server to complete its processing. Complains if the FUSE
+  // server responds any failure during tests.
+  void WaitServerComplete();
 
-  // ReceiveExpected is the FUSE server side's corresponding code of
-  // `SetExpected()`. Save the request-response pair into its memory.
-  void ReceiveExpected();
+  // The FUSE server stays here and waits next command or FUSE request until it
+  // is terminated.
+  void ServerFuseLoop();
 
-  // MarkDone is used by the FUSE server to tell testing main if it's OK to
-  // proceed next command.
-  void MarkDone(bool success);
+  // Used by the FUSE server to tell testing thread if it is OK to proceed next
+  // command. Will be issued after processing each FuseTestCmd.
+  void ServerCompleteWith(bool success);
 
-  // FuseLoop is where the FUSE server stay until it is terminated.
-  void FuseLoop();
+  // Consumes the first FUSE request when mounting FUSE. Replies with a
+  // response with empty payload.
+  PosixError ServerConsumeFuseInit(const struct fuse_init_out* payload);
 
-  // SetUpFuseServer creates 2 pipes for communication and forks FUSE server.
-  void SetUpFuseServer();
+  // A command switch that dispatch different FuseTestCmd to its handler.
+  void ServerHandleCommand();
 
-  // GetPayloadSize is a helper function to get the number of bytes of a
-  // specific FUSE operation struct.
-  size_t GetPayloadSize(uint32_t opcode, bool in);
+  // The FUSE server side's corresponding code of `SetServerResponse()`.
+  // Handles `kSetResponse` command. Saves the fake response into its output
+  // memory queue.
+  void ServerReceiveResponse();
+
+  // The FUSE server side's corresponding code of `SetServerInodeLookup()`.
+  // Handles `kSetInodeLookup` command. Receives an expected file mode and
+  // file path under the mount point.
+  void ServerReceiveInodeLookup();
+
+  // The FUSE server side's corresponding code of `GetServerActualRequest()`.
+  // Handles `kGetRequest` command. Sends the next received request pointed by
+  // the cursor.
+  void ServerSendReceivedRequest();
+
+  // Sends a uint32_t data via socket.
+  inline void ServerSendData(uint32_t data);
+
+  // The FUSE server side's corresponding code of `SkipServerActualRequest()`.
+  // Handles `kSkipRequest` command. Skip the request pointed by current cursor.
+  void ServerSkipReceivedRequest();
+
+  // Handles FUSE request sent to /dev/fuse by its saved responses.
+  void ServerProcessFuseRequest();
+
+  // Responds to FUSE request with a saved data.
+  void ServerRespondFuseSuccess(FuseMemBuffer& mem_buf,
+                                const FuseMemBlock& block, uint64_t unique);
+
+  // Responds an error header to /dev/fuse when bad thing happens.
+  void ServerRespondFuseError(uint64_t unique);
 
   int dev_fd_;
-  int set_expected_[2];
-  int done_[2];
-
-  std::vector<char> buf_;
-  std::vector<char> mem_in_;
-  std::vector<char> mem_out_;
-  ssize_t len_in_;
-  ssize_t len_out_;
+  int sock_[2];
+
+  uint64_t nodeid_;
+  std::unordered_map<std::string, FuseMemBlock> lookup_map_;
+
+  FuseMemBuffer requests_;
+  FuseMemBuffer responses_;
+  FuseMemBuffer lookups_;
 };
 
 }  // namespace testing
diff --git a/test/fuse/linux/fuse_fd_util.cc b/test/fuse/linux/fuse_fd_util.cc
new file mode 100644
index 000000000..30d1157bb
--- /dev/null
+++ b/test/fuse/linux/fuse_fd_util.cc
@@ -0,0 +1,61 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "test/fuse/linux/fuse_fd_util.h"
+
+#include <fcntl.h>
+#include <linux/fuse.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+
+#include <string>
+#include <vector>
+
+#include "test/util/cleanup.h"
+#include "test/util/file_descriptor.h"
+#include "test/util/fuse_util.h"
+#include "test/util/posix_error.h"
+
+namespace gvisor {
+namespace testing {
+
+PosixErrorOr<FileDescriptor> FuseFdTest::OpenPath(const std::string &path,
+                                                  uint32_t flags, uint64_t fh) {
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_open_out),
+  };
+  struct fuse_open_out out_payload = {
+      .fh = fh,
+      .open_flags = flags,
+  };
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_OPEN, iov_out);
+
+  auto res = Open(path.c_str(), flags);
+  if (res.ok()) {
+    SkipServerActualRequest();
+  }
+  return res;
+}
+
+Cleanup FuseFdTest::CloseFD(FileDescriptor &fd) {
+  return Cleanup([&] {
+    close(fd.release());
+    SkipServerActualRequest();
+  });
+}
+
+}  // namespace testing
+}  // namespace gvisor
diff --git a/test/fuse/linux/fuse_fd_util.h b/test/fuse/linux/fuse_fd_util.h
new file mode 100644
index 000000000..066185c94
--- /dev/null
+++ b/test/fuse/linux/fuse_fd_util.h
@@ -0,0 +1,48 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef GVISOR_TEST_FUSE_FUSE_FD_UTIL_H_
+#define GVISOR_TEST_FUSE_FUSE_FD_UTIL_H_
+
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <string>
+
+#include "test/fuse/linux/fuse_base.h"
+#include "test/util/cleanup.h"
+#include "test/util/file_descriptor.h"
+#include "test/util/posix_error.h"
+
+namespace gvisor {
+namespace testing {
+
+class FuseFdTest : public FuseTest {
+ public:
+  // Sets the FUSE server to respond to a FUSE_OPEN with corresponding flags and
+  // fh. Then does a real file system open on the absolute path to get an fd.
+  PosixErrorOr<FileDescriptor> OpenPath(const std::string &path,
+                                        uint32_t flags = O_RDONLY,
+                                        uint64_t fh = 1);
+
+  // Returns a cleanup object that closes the fd when it is destroyed. After
+  // the close is done, tells the FUSE server to skip this FUSE_RELEASE.
+  Cleanup CloseFD(FileDescriptor &fd);
+};
+
+}  // namespace testing
+}  // namespace gvisor
+
+#endif  // GVISOR_TEST_FUSE_FUSE_FD_UTIL_H_
diff --git a/test/fuse/linux/mkdir_test.cc b/test/fuse/linux/mkdir_test.cc
new file mode 100644
index 000000000..9647cb93f
--- /dev/null
+++ b/test/fuse/linux/mkdir_test.cc
@@ -0,0 +1,88 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fuse.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "test/fuse/linux/fuse_base.h"
+#include "test/util/fuse_util.h"
+#include "test/util/temp_umask.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+class MkdirTest : public FuseTest {
+ protected:
+  const std::string test_dir_ = "test_dir";
+  const mode_t perms_ = S_IRWXU | S_IRWXG | S_IRWXO;
+};
+
+TEST_F(MkdirTest, CreateDir) {
+  const std::string test_dir_path_ =
+      JoinPath(mount_point_.path().c_str(), test_dir_);
+  const mode_t new_umask = 0077;
+
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_entry_out),
+  };
+  struct fuse_entry_out out_payload = DefaultEntryOut(S_IFDIR | perms_, 5);
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_MKDIR, iov_out);
+  TempUmask mask(new_umask);
+  ASSERT_THAT(mkdir(test_dir_path_.c_str(), 0777), SyscallSucceeds());
+
+  struct fuse_in_header in_header;
+  struct fuse_mkdir_in in_payload;
+  std::vector<char> actual_dir(test_dir_.length() + 1);
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload, actual_dir);
+  GetServerActualRequest(iov_in);
+
+  EXPECT_EQ(in_header.len,
+            sizeof(in_header) + sizeof(in_payload) + test_dir_.length() + 1);
+  EXPECT_EQ(in_header.opcode, FUSE_MKDIR);
+  EXPECT_EQ(in_payload.mode & 0777, perms_ & ~new_umask);
+  EXPECT_EQ(in_payload.umask, new_umask);
+  EXPECT_EQ(std::string(actual_dir.data()), test_dir_);
+}
+
+TEST_F(MkdirTest, FileTypeError) {
+  const std::string test_dir_path_ =
+      JoinPath(mount_point_.path().c_str(), test_dir_);
+
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_entry_out),
+  };
+  struct fuse_entry_out out_payload = DefaultEntryOut(S_IFREG | perms_, 5);
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_MKDIR, iov_out);
+  ASSERT_THAT(mkdir(test_dir_path_.c_str(), 0777), SyscallFailsWithErrno(EIO));
+  SkipServerActualRequest();
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor
diff --git a/test/fuse/linux/mknod_test.cc b/test/fuse/linux/mknod_test.cc
new file mode 100644
index 000000000..74c74d76b
--- /dev/null
+++ b/test/fuse/linux/mknod_test.cc
@@ -0,0 +1,107 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fuse.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "test/fuse/linux/fuse_base.h"
+#include "test/util/fuse_util.h"
+#include "test/util/temp_umask.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+class MknodTest : public FuseTest {
+ protected:
+  const std::string test_file_ = "test_file";
+  const mode_t perms_ = S_IRWXU | S_IRWXG | S_IRWXO;
+};
+
+TEST_F(MknodTest, RegularFile) {
+  const std::string test_file_path =
+      JoinPath(mount_point_.path().c_str(), test_file_);
+  const mode_t new_umask = 0077;
+
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_entry_out),
+  };
+  struct fuse_entry_out out_payload = DefaultEntryOut(S_IFREG | perms_, 5);
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_MKNOD, iov_out);
+  TempUmask mask(new_umask);
+  ASSERT_THAT(mknod(test_file_path.c_str(), perms_, 0), SyscallSucceeds());
+
+  struct fuse_in_header in_header;
+  struct fuse_mknod_in in_payload;
+  std::vector<char> actual_file(test_file_.length() + 1);
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload, actual_file);
+  GetServerActualRequest(iov_in);
+
+  EXPECT_EQ(in_header.len,
+            sizeof(in_header) + sizeof(in_payload) + test_file_.length() + 1);
+  EXPECT_EQ(in_header.opcode, FUSE_MKNOD);
+  EXPECT_EQ(in_payload.mode & 0777, perms_ & ~new_umask);
+  EXPECT_EQ(in_payload.umask, new_umask);
+  EXPECT_EQ(in_payload.rdev, 0);
+  EXPECT_EQ(std::string(actual_file.data()), test_file_);
+}
+
+TEST_F(MknodTest, FileTypeError) {
+  const std::string test_file_path =
+      JoinPath(mount_point_.path().c_str(), test_file_);
+
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_entry_out),
+  };
+  // server return directory instead of regular file should cause an error.
+  struct fuse_entry_out out_payload = DefaultEntryOut(S_IFDIR | perms_, 5);
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_MKNOD, iov_out);
+  ASSERT_THAT(mknod(test_file_path.c_str(), perms_, 0),
+              SyscallFailsWithErrno(EIO));
+  SkipServerActualRequest();
+}
+
+TEST_F(MknodTest, NodeIDError) {
+  const std::string test_file_path =
+      JoinPath(mount_point_.path().c_str(), test_file_);
+
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_entry_out),
+  };
+  struct fuse_entry_out out_payload =
+      DefaultEntryOut(S_IFREG | perms_, FUSE_ROOT_ID);
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_MKNOD, iov_out);
+  ASSERT_THAT(mknod(test_file_path.c_str(), perms_, 0),
+              SyscallFailsWithErrno(EIO));
+  SkipServerActualRequest();
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor
diff --git a/test/fuse/linux/open_test.cc b/test/fuse/linux/open_test.cc
new file mode 100644
index 000000000..4b0c4a805
--- /dev/null
+++ b/test/fuse/linux/open_test.cc
@@ -0,0 +1,128 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fuse.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <string>
+
+#include "gtest/gtest.h"
+#include "test/fuse/linux/fuse_base.h"
+#include "test/util/fuse_util.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+class OpenTest : public FuseTest {
+  // OpenTest doesn't care the release request when close a fd,
+  // so doesn't check leftover requests when tearing down.
+  void TearDown() { UnmountFuse(); }
+
+ protected:
+  const std::string test_file_ = "test_file";
+  const mode_t regular_file_ = S_IFREG | S_IRWXU | S_IRWXG | S_IRWXO;
+
+  struct fuse_open_out out_payload_ = {
+      .fh = 1,
+      .open_flags = O_RDWR,
+  };
+};
+
+TEST_F(OpenTest, RegularFile) {
+  const std::string test_file_path =
+      JoinPath(mount_point_.path().c_str(), test_file_);
+  SetServerInodeLookup(test_file_, regular_file_);
+
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_open_out),
+  };
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload_);
+  SetServerResponse(FUSE_OPEN, iov_out);
+  FileDescriptor fd =
+      ASSERT_NO_ERRNO_AND_VALUE(Open(test_file_path.c_str(), O_RDWR));
+
+  struct fuse_in_header in_header;
+  struct fuse_open_in in_payload;
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload);
+  GetServerActualRequest(iov_in);
+
+  EXPECT_EQ(in_header.len, sizeof(in_header) + sizeof(in_payload));
+  EXPECT_EQ(in_header.opcode, FUSE_OPEN);
+  EXPECT_EQ(in_payload.flags, O_RDWR);
+  EXPECT_THAT(fcntl(fd.get(), F_GETFL), SyscallSucceedsWithValue(O_RDWR));
+}
+
+TEST_F(OpenTest, SetNoOpen) {
+  const std::string test_file_path =
+      JoinPath(mount_point_.path().c_str(), test_file_);
+  SetServerInodeLookup(test_file_, regular_file_);
+
+  // ENOSYS indicates open is not implemented.
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_open_out),
+      .error = -ENOSYS,
+  };
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload_);
+  SetServerResponse(FUSE_OPEN, iov_out);
+  ASSERT_NO_ERRNO_AND_VALUE(Open(test_file_path.c_str(), O_RDWR));
+  SkipServerActualRequest();
+
+  // check open doesn't send new request.
+  uint32_t recieved_before = GetServerTotalReceivedBytes();
+  ASSERT_NO_ERRNO_AND_VALUE(Open(test_file_path.c_str(), O_RDWR));
+  EXPECT_EQ(GetServerTotalReceivedBytes(), recieved_before);
+}
+
+TEST_F(OpenTest, OpenFail) {
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_open_out),
+      .error = -ENOENT,
+  };
+
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload_);
+  SetServerResponse(FUSE_OPENDIR, iov_out);
+  ASSERT_THAT(open(mount_point_.path().c_str(), O_RDWR),
+              SyscallFailsWithErrno(ENOENT));
+
+  struct fuse_in_header in_header;
+  struct fuse_open_in in_payload;
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload);
+  GetServerActualRequest(iov_in);
+
+  EXPECT_EQ(in_header.len, sizeof(in_header) + sizeof(in_payload));
+  EXPECT_EQ(in_header.opcode, FUSE_OPENDIR);
+  EXPECT_EQ(in_payload.flags, O_RDWR);
+}
+
+TEST_F(OpenTest, DirectoryFlagOnRegularFile) {
+  const std::string test_file_path =
+      JoinPath(mount_point_.path().c_str(), test_file_);
+
+  SetServerInodeLookup(test_file_, regular_file_);
+  ASSERT_THAT(open(test_file_path.c_str(), O_RDWR | O_DIRECTORY),
+              SyscallFailsWithErrno(ENOTDIR));
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor
diff --git a/test/fuse/linux/read_test.cc b/test/fuse/linux/read_test.cc
new file mode 100644
index 000000000..88fc299d8
--- /dev/null
+++ b/test/fuse/linux/read_test.cc
@@ -0,0 +1,390 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fuse.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "test/fuse/linux/fuse_base.h"
+#include "test/util/fuse_util.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+class ReadTest : public FuseTest {
+  void SetUp() override {
+    FuseTest::SetUp();
+    test_file_path_ = JoinPath(mount_point_.path().c_str(), test_file_);
+  }
+
+  // TearDown overrides the parent's function
+  // to skip checking the unconsumed release request at the end.
+  void TearDown() override { UnmountFuse(); }
+
+ protected:
+  const std::string test_file_ = "test_file";
+  const mode_t test_file_mode_ = S_IFREG | S_IRWXU | S_IRWXG | S_IRWXO;
+  const uint64_t test_fh_ = 1;
+  const uint32_t open_flag_ = O_RDWR;
+
+  std::string test_file_path_;
+
+  PosixErrorOr<FileDescriptor> OpenTestFile(const std::string &path,
+                                            uint64_t size = 512) {
+    SetServerInodeLookup(test_file_, test_file_mode_, size);
+
+    struct fuse_out_header out_header_open = {
+        .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_open_out),
+    };
+    struct fuse_open_out out_payload_open = {
+        .fh = test_fh_,
+        .open_flags = open_flag_,
+    };
+    auto iov_out_open = FuseGenerateIovecs(out_header_open, out_payload_open);
+    SetServerResponse(FUSE_OPEN, iov_out_open);
+
+    auto res = Open(path.c_str(), open_flag_);
+    if (res.ok()) {
+      SkipServerActualRequest();
+    }
+    return res;
+  }
+};
+
+class ReadTestSmallMaxRead : public ReadTest {
+  void SetUp() override {
+    MountFuse(mountOpts);
+    SetUpFuseServer();
+    test_file_path_ = JoinPath(mount_point_.path().c_str(), test_file_);
+  }
+
+ protected:
+  constexpr static char mountOpts[] =
+      "rootmode=755,user_id=0,group_id=0,max_read=4096";
+  // 4096 is hard-coded as the max_read in mount options.
+  const int size_fragment = 4096;
+};
+
+TEST_F(ReadTest, ReadWhole) {
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_));
+
+  // Prepare for the read.
+  const int n_read = 5;
+  std::vector<char> data(n_read);
+  RandomizeBuffer(data.data(), data.size());
+  struct fuse_out_header out_header_read = {
+      .len =
+          static_cast<uint32_t>(sizeof(struct fuse_out_header) + data.size()),
+  };
+  auto iov_out_read = FuseGenerateIovecs(out_header_read, data);
+  SetServerResponse(FUSE_READ, iov_out_read);
+
+  // Read the whole "file".
+  std::vector<char> buf(n_read);
+  EXPECT_THAT(read(fd.get(), buf.data(), n_read),
+              SyscallSucceedsWithValue(n_read));
+
+  // Check the read request.
+  struct fuse_in_header in_header_read;
+  struct fuse_read_in in_payload_read;
+  auto iov_in = FuseGenerateIovecs(in_header_read, in_payload_read);
+  GetServerActualRequest(iov_in);
+
+  EXPECT_EQ(in_payload_read.fh, test_fh_);
+  EXPECT_EQ(in_header_read.len,
+            sizeof(in_header_read) + sizeof(in_payload_read));
+  EXPECT_EQ(in_header_read.opcode, FUSE_READ);
+  EXPECT_EQ(in_payload_read.offset, 0);
+  EXPECT_EQ(buf, data);
+}
+
+TEST_F(ReadTest, ReadPartial) {
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_));
+
+  // Prepare for the read.
+  const int n_data = 10;
+  std::vector<char> data(n_data);
+  RandomizeBuffer(data.data(), data.size());
+  // Note: due to read ahead, current read implementation will treat any
+  // response that is longer than requested as correct (i.e. not reach the EOF).
+  // Therefore, the test below should make sure the size to read does not exceed
+  // n_data.
+  struct fuse_out_header out_header_read = {
+      .len =
+          static_cast<uint32_t>(sizeof(struct fuse_out_header) + data.size()),
+  };
+  auto iov_out_read = FuseGenerateIovecs(out_header_read, data);
+  struct fuse_in_header in_header_read;
+  struct fuse_read_in in_payload_read;
+  auto iov_in = FuseGenerateIovecs(in_header_read, in_payload_read);
+
+  std::vector<char> buf(n_data);
+
+  // Read 1 bytes.
+  SetServerResponse(FUSE_READ, iov_out_read);
+  EXPECT_THAT(read(fd.get(), buf.data(), 1), SyscallSucceedsWithValue(1));
+
+  // Check the 1-byte read request.
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_payload_read.fh, test_fh_);
+  EXPECT_EQ(in_header_read.len,
+            sizeof(in_header_read) + sizeof(in_payload_read));
+  EXPECT_EQ(in_header_read.opcode, FUSE_READ);
+  EXPECT_EQ(in_payload_read.offset, 0);
+
+  // Read 3 bytes.
+  SetServerResponse(FUSE_READ, iov_out_read);
+  EXPECT_THAT(read(fd.get(), buf.data(), 3), SyscallSucceedsWithValue(3));
+
+  // Check the 3-byte read request.
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_payload_read.fh, test_fh_);
+  EXPECT_EQ(in_payload_read.offset, 1);
+
+  // Read 5 bytes.
+  SetServerResponse(FUSE_READ, iov_out_read);
+  EXPECT_THAT(read(fd.get(), buf.data(), 5), SyscallSucceedsWithValue(5));
+
+  // Check the 5-byte read request.
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_payload_read.fh, test_fh_);
+  EXPECT_EQ(in_payload_read.offset, 4);
+}
+
+TEST_F(ReadTest, PRead) {
+  const int file_size = 512;
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_, file_size));
+
+  // Prepare for the read.
+  const int n_read = 5;
+  std::vector<char> data(n_read);
+  RandomizeBuffer(data.data(), data.size());
+  struct fuse_out_header out_header_read = {
+      .len =
+          static_cast<uint32_t>(sizeof(struct fuse_out_header) + data.size()),
+  };
+  auto iov_out_read = FuseGenerateIovecs(out_header_read, data);
+  SetServerResponse(FUSE_READ, iov_out_read);
+
+  // Read some bytes.
+  std::vector<char> buf(n_read);
+  const int offset_read = file_size >> 1;
+  EXPECT_THAT(pread(fd.get(), buf.data(), n_read, offset_read),
+              SyscallSucceedsWithValue(n_read));
+
+  // Check the read request.
+  struct fuse_in_header in_header_read;
+  struct fuse_read_in in_payload_read;
+  auto iov_in = FuseGenerateIovecs(in_header_read, in_payload_read);
+  GetServerActualRequest(iov_in);
+
+  EXPECT_EQ(in_payload_read.fh, test_fh_);
+  EXPECT_EQ(in_header_read.len,
+            sizeof(in_header_read) + sizeof(in_payload_read));
+  EXPECT_EQ(in_header_read.opcode, FUSE_READ);
+  EXPECT_EQ(in_payload_read.offset, offset_read);
+  EXPECT_EQ(buf, data);
+}
+
+TEST_F(ReadTest, ReadZero) {
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_));
+
+  // Issue the read.
+  std::vector<char> buf;
+  EXPECT_THAT(read(fd.get(), buf.data(), 0), SyscallSucceedsWithValue(0));
+}
+
+TEST_F(ReadTest, ReadShort) {
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_));
+
+  // Prepare for the short read.
+  const int n_read = 5;
+  std::vector<char> data(n_read >> 1);
+  RandomizeBuffer(data.data(), data.size());
+  struct fuse_out_header out_header_read = {
+      .len =
+          static_cast<uint32_t>(sizeof(struct fuse_out_header) + data.size()),
+  };
+  auto iov_out_read = FuseGenerateIovecs(out_header_read, data);
+  SetServerResponse(FUSE_READ, iov_out_read);
+
+  // Read the whole "file".
+  std::vector<char> buf(n_read);
+  EXPECT_THAT(read(fd.get(), buf.data(), n_read),
+              SyscallSucceedsWithValue(data.size()));
+
+  // Check the read request.
+  struct fuse_in_header in_header_read;
+  struct fuse_read_in in_payload_read;
+  auto iov_in = FuseGenerateIovecs(in_header_read, in_payload_read);
+  GetServerActualRequest(iov_in);
+
+  EXPECT_EQ(in_payload_read.fh, test_fh_);
+  EXPECT_EQ(in_header_read.len,
+            sizeof(in_header_read) + sizeof(in_payload_read));
+  EXPECT_EQ(in_header_read.opcode, FUSE_READ);
+  EXPECT_EQ(in_payload_read.offset, 0);
+  std::vector<char> short_buf(buf.begin(), buf.begin() + data.size());
+  EXPECT_EQ(short_buf, data);
+}
+
+TEST_F(ReadTest, ReadShortEOF) {
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_));
+
+  // Prepare for the short read.
+  struct fuse_out_header out_header_read = {
+      .len = static_cast<uint32_t>(sizeof(struct fuse_out_header)),
+  };
+  auto iov_out_read = FuseGenerateIovecs(out_header_read);
+  SetServerResponse(FUSE_READ, iov_out_read);
+
+  // Read the whole "file".
+  const int n_read = 10;
+  std::vector<char> buf(n_read);
+  EXPECT_THAT(read(fd.get(), buf.data(), n_read), SyscallSucceedsWithValue(0));
+
+  // Check the read request.
+  struct fuse_in_header in_header_read;
+  struct fuse_read_in in_payload_read;
+  auto iov_in = FuseGenerateIovecs(in_header_read, in_payload_read);
+  GetServerActualRequest(iov_in);
+
+  EXPECT_EQ(in_payload_read.fh, test_fh_);
+  EXPECT_EQ(in_header_read.len,
+            sizeof(in_header_read) + sizeof(in_payload_read));
+  EXPECT_EQ(in_header_read.opcode, FUSE_READ);
+  EXPECT_EQ(in_payload_read.offset, 0);
+}
+
+TEST_F(ReadTestSmallMaxRead, ReadSmallMaxRead) {
+  const int n_fragment = 10;
+  const int n_read = size_fragment * n_fragment;
+
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_, n_read));
+
+  // Prepare for the read.
+  std::vector<char> data(size_fragment);
+  RandomizeBuffer(data.data(), data.size());
+  struct fuse_out_header out_header_read = {
+      .len =
+          static_cast<uint32_t>(sizeof(struct fuse_out_header) + data.size()),
+  };
+  auto iov_out_read = FuseGenerateIovecs(out_header_read, data);
+
+  for (int i = 0; i < n_fragment; ++i) {
+    SetServerResponse(FUSE_READ, iov_out_read);
+  }
+
+  // Read the whole "file".
+  std::vector<char> buf(n_read);
+  EXPECT_THAT(read(fd.get(), buf.data(), n_read),
+              SyscallSucceedsWithValue(n_read));
+
+  ASSERT_EQ(GetServerNumUnsentResponses(), 0);
+  ASSERT_EQ(GetServerNumUnconsumedRequests(), n_fragment);
+
+  // Check each read segment.
+  struct fuse_in_header in_header_read;
+  struct fuse_read_in in_payload_read;
+  auto iov_in = FuseGenerateIovecs(in_header_read, in_payload_read);
+
+  for (int i = 0; i < n_fragment; ++i) {
+    GetServerActualRequest(iov_in);
+    EXPECT_EQ(in_payload_read.fh, test_fh_);
+    EXPECT_EQ(in_header_read.len,
+              sizeof(in_header_read) + sizeof(in_payload_read));
+    EXPECT_EQ(in_header_read.opcode, FUSE_READ);
+    EXPECT_EQ(in_payload_read.offset, i * size_fragment);
+    EXPECT_EQ(in_payload_read.size, size_fragment);
+
+    auto it = buf.begin() + i * size_fragment;
+    EXPECT_EQ(std::vector<char>(it, it + size_fragment), data);
+  }
+}
+
+TEST_F(ReadTestSmallMaxRead, ReadSmallMaxReadShort) {
+  const int n_fragment = 10;
+  const int n_read = size_fragment * n_fragment;
+
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_, n_read));
+
+  // Prepare for the read.
+  std::vector<char> data(size_fragment);
+  RandomizeBuffer(data.data(), data.size());
+  struct fuse_out_header out_header_read = {
+      .len =
+          static_cast<uint32_t>(sizeof(struct fuse_out_header) + data.size()),
+  };
+  auto iov_out_read = FuseGenerateIovecs(out_header_read, data);
+
+  for (int i = 0; i < n_fragment - 1; ++i) {
+    SetServerResponse(FUSE_READ, iov_out_read);
+  }
+
+  // The last fragment is a short read.
+  std::vector<char> half_data(data.begin(), data.begin() + (data.size() >> 1));
+  struct fuse_out_header out_header_read_short = {
+      .len = static_cast<uint32_t>(sizeof(struct fuse_out_header) +
+                                   half_data.size()),
+  };
+  auto iov_out_read_short =
+      FuseGenerateIovecs(out_header_read_short, half_data);
+  SetServerResponse(FUSE_READ, iov_out_read_short);
+
+  // Read the whole "file".
+  std::vector<char> buf(n_read);
+  EXPECT_THAT(read(fd.get(), buf.data(), n_read),
+              SyscallSucceedsWithValue(n_read - (data.size() >> 1)));
+
+  ASSERT_EQ(GetServerNumUnsentResponses(), 0);
+  ASSERT_EQ(GetServerNumUnconsumedRequests(), n_fragment);
+
+  // Check each read segment.
+  struct fuse_in_header in_header_read;
+  struct fuse_read_in in_payload_read;
+  auto iov_in = FuseGenerateIovecs(in_header_read, in_payload_read);
+
+  for (int i = 0; i < n_fragment; ++i) {
+    GetServerActualRequest(iov_in);
+    EXPECT_EQ(in_payload_read.fh, test_fh_);
+    EXPECT_EQ(in_header_read.len,
+              sizeof(in_header_read) + sizeof(in_payload_read));
+    EXPECT_EQ(in_header_read.opcode, FUSE_READ);
+    EXPECT_EQ(in_payload_read.offset, i * size_fragment);
+    EXPECT_EQ(in_payload_read.size, size_fragment);
+
+    auto it = buf.begin() + i * size_fragment;
+    if (i != n_fragment - 1) {
+      EXPECT_EQ(std::vector<char>(it, it + data.size()), data);
+    } else {
+      EXPECT_EQ(std::vector<char>(it, it + half_data.size()), half_data);
+    }
+  }
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor
diff --git a/test/fuse/linux/readdir_test.cc b/test/fuse/linux/readdir_test.cc
new file mode 100644
index 000000000..2afb4b062
--- /dev/null
+++ b/test/fuse/linux/readdir_test.cc
@@ -0,0 +1,193 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fuse.h>
+#include <linux/unistd.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <string>
+
+#include "gtest/gtest.h"
+#include "test/fuse/linux/fuse_base.h"
+#include "test/util/fuse_util.h"
+#include "test/util/test_util.h"
+
+#define FUSE_NAME_OFFSET offsetof(struct fuse_dirent, name)
+#define FUSE_DIRENT_ALIGN(x) \
+  (((x) + sizeof(uint64_t) - 1) & ~(sizeof(uint64_t) - 1))
+#define FUSE_DIRENT_SIZE(d) FUSE_DIRENT_ALIGN(FUSE_NAME_OFFSET + (d)->namelen)
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+class ReaddirTest : public FuseTest {
+ public:
+  void fill_fuse_dirent(char *buf, const char *name, uint64_t ino) {
+    size_t namelen = strlen(name);
+    size_t entlen = FUSE_NAME_OFFSET + namelen;
+    size_t entlen_padded = FUSE_DIRENT_ALIGN(entlen);
+    struct fuse_dirent *dirent;
+
+    dirent = reinterpret_cast<struct fuse_dirent *>(buf);
+    dirent->ino = ino;
+    dirent->namelen = namelen;
+    memcpy(dirent->name, name, namelen);
+    memset(dirent->name + namelen, 0, entlen_padded - entlen);
+  }
+
+ protected:
+  const std::string test_dir_name_ = "test_dir";
+};
+
+TEST_F(ReaddirTest, SingleEntry) {
+  const std::string test_dir_path =
+      JoinPath(mount_point_.path().c_str(), test_dir_name_);
+
+  const uint64_t ino_dir = 1024;
+  // We need to make sure the test dir is a directory that can be found.
+  mode_t expected_mode =
+      S_IFDIR | S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
+  struct fuse_attr dir_attr = {
+      .ino = ino_dir,
+      .size = 512,
+      .blocks = 4,
+      .mode = expected_mode,
+      .blksize = 4096,
+  };
+
+  // We need to make sure the test dir is a directory that can be found.
+  struct fuse_out_header lookup_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_entry_out),
+  };
+  struct fuse_entry_out lookup_payload = {
+      .nodeid = 1,
+      .entry_valid = true,
+      .attr_valid = true,
+      .attr = dir_attr,
+  };
+
+  struct fuse_out_header open_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_open_out),
+  };
+  struct fuse_open_out open_payload = {
+      .fh = 1,
+  };
+  auto iov_out = FuseGenerateIovecs(lookup_header, lookup_payload);
+  SetServerResponse(FUSE_LOOKUP, iov_out);
+
+  iov_out = FuseGenerateIovecs(open_header, open_payload);
+  SetServerResponse(FUSE_OPENDIR, iov_out);
+
+  FileDescriptor fd =
+      ASSERT_NO_ERRNO_AND_VALUE(Open(test_dir_path.c_str(), O_RDONLY));
+
+  // The open command makes two syscalls. Lookup the dir file and open.
+  // We don't need to inspect those headers in this test.
+  SkipServerActualRequest();  // LOOKUP.
+  SkipServerActualRequest();  // OPENDIR.
+
+  // Readdir test code.
+  std::string dot = ".";
+  std::string dot_dot = "..";
+  std::string test_file = "testFile";
+
+  // Figure out how many dirents to send over and allocate them appropriately.
+  // Each dirent has a dynamic name and a static metadata part. The dirent size
+  // is aligned to being a multiple of 8.
+  size_t dot_file_dirent_size =
+      FUSE_DIRENT_ALIGN(dot.length() + FUSE_NAME_OFFSET);
+  size_t dot_dot_file_dirent_size =
+      FUSE_DIRENT_ALIGN(dot_dot.length() + FUSE_NAME_OFFSET);
+  size_t test_file_dirent_size =
+      FUSE_DIRENT_ALIGN(test_file.length() + FUSE_NAME_OFFSET);
+
+  // Create an appropriately sized payload.
+  size_t readdir_payload_size =
+      test_file_dirent_size + dot_file_dirent_size + dot_dot_file_dirent_size;
+  std::vector<char> readdir_payload_vec(readdir_payload_size);
+  char *readdir_payload = readdir_payload_vec.data();
+
+  // Use fake ino for other directories.
+  fill_fuse_dirent(readdir_payload, dot.c_str(), ino_dir - 2);
+  fill_fuse_dirent(readdir_payload + dot_file_dirent_size, dot_dot.c_str(),
+                   ino_dir - 1);
+  fill_fuse_dirent(
+      readdir_payload + dot_file_dirent_size + dot_dot_file_dirent_size,
+      test_file.c_str(), ino_dir);
+
+  struct fuse_out_header readdir_header = {
+      .len = uint32_t(sizeof(struct fuse_out_header) + readdir_payload_size),
+  };
+  struct fuse_out_header readdir_header_break = {
+      .len = uint32_t(sizeof(struct fuse_out_header)),
+  };
+
+  iov_out = FuseGenerateIovecs(readdir_header, readdir_payload_vec);
+  SetServerResponse(FUSE_READDIR, iov_out);
+
+  iov_out = FuseGenerateIovecs(readdir_header_break);
+  SetServerResponse(FUSE_READDIR, iov_out);
+
+  std::vector<char> buf(4090, 0);
+  int nread, off = 0, i = 0;
+  EXPECT_THAT(
+      nread = syscall(__NR_getdents64, fd.get(), buf.data(), buf.size()),
+      SyscallSucceeds());
+  for (; off < nread;) {
+    struct dirent64 *ent = (struct dirent64 *)(buf.data() + off);
+    off += ent->d_reclen;
+    switch (i++) {
+      case 0:
+        EXPECT_EQ(std::string(ent->d_name), dot);
+        break;
+      case 1:
+        EXPECT_EQ(std::string(ent->d_name), dot_dot);
+        break;
+      case 2:
+        EXPECT_EQ(std::string(ent->d_name), test_file);
+        break;
+    }
+  }
+
+  EXPECT_THAT(
+      nread = syscall(__NR_getdents64, fd.get(), buf.data(), buf.size()),
+      SyscallSucceedsWithValue(0));
+
+  SkipServerActualRequest();  // READDIR.
+  SkipServerActualRequest();  // READDIR with no data.
+
+  // Clean up.
+  fd.reset(-1);
+
+  struct fuse_in_header in_header;
+  struct fuse_release_in in_payload;
+
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload);
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_header.len, sizeof(in_header) + sizeof(in_payload));
+  EXPECT_EQ(in_header.opcode, FUSE_RELEASEDIR);
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor
diff --git a/test/fuse/linux/readlink_test.cc b/test/fuse/linux/readlink_test.cc
new file mode 100644
index 000000000..2cba8fc23
--- /dev/null
+++ b/test/fuse/linux/readlink_test.cc
@@ -0,0 +1,85 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fuse.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "test/fuse/linux/fuse_base.h"
+#include "test/util/fuse_util.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+class ReadlinkTest : public FuseTest {
+ protected:
+  const std::string test_file_ = "test_file_";
+  const mode_t perms_ = S_IRWXU | S_IRWXG | S_IRWXO;
+};
+
+TEST_F(ReadlinkTest, ReadSymLink) {
+  const std::string symlink_path =
+      JoinPath(mount_point_.path().c_str(), test_file_);
+  SetServerInodeLookup(test_file_, S_IFLNK | perms_);
+
+  struct fuse_out_header out_header = {
+      .len = static_cast<uint32_t>(sizeof(struct fuse_out_header)) +
+             static_cast<uint32_t>(test_file_.length()) + 1,
+  };
+  std::string link = test_file_;
+  auto iov_out = FuseGenerateIovecs(out_header, link);
+  SetServerResponse(FUSE_READLINK, iov_out);
+  const std::string actual_link =
+      ASSERT_NO_ERRNO_AND_VALUE(ReadLink(symlink_path));
+
+  struct fuse_in_header in_header;
+  auto iov_in = FuseGenerateIovecs(in_header);
+  GetServerActualRequest(iov_in);
+
+  EXPECT_EQ(in_header.len, sizeof(in_header));
+  EXPECT_EQ(in_header.opcode, FUSE_READLINK);
+  EXPECT_EQ(0, memcmp(actual_link.c_str(), link.data(), link.size()));
+
+  // next readlink should have link cached, so shouldn't have new request to
+  // server.
+  uint32_t recieved_before = GetServerTotalReceivedBytes();
+  ASSERT_NO_ERRNO(ReadLink(symlink_path));
+  EXPECT_EQ(GetServerTotalReceivedBytes(), recieved_before);
+}
+
+TEST_F(ReadlinkTest, NotSymlink) {
+  const std::string test_file_path =
+      JoinPath(mount_point_.path().c_str(), test_file_);
+  SetServerInodeLookup(test_file_, S_IFREG | perms_);
+
+  std::vector<char> buf(PATH_MAX + 1);
+  ASSERT_THAT(readlink(test_file_path.c_str(), buf.data(), PATH_MAX),
+              SyscallFailsWithErrno(EINVAL));
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor
diff --git a/test/fuse/linux/release_test.cc b/test/fuse/linux/release_test.cc
new file mode 100644
index 000000000..b5adb0870
--- /dev/null
+++ b/test/fuse/linux/release_test.cc
@@ -0,0 +1,74 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fuse.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "test/fuse/linux/fuse_base.h"
+#include "test/util/fuse_util.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+class ReleaseTest : public FuseTest {
+ protected:
+  const std::string test_file_ = "test_file";
+};
+
+TEST_F(ReleaseTest, RegularFile) {
+  const std::string test_file_path =
+      JoinPath(mount_point_.path().c_str(), test_file_);
+  SetServerInodeLookup(test_file_, S_IFREG | S_IRWXU | S_IRWXG | S_IRWXO);
+
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_open_out),
+  };
+  struct fuse_open_out out_payload = {
+      .fh = 1,
+      .open_flags = O_RDWR,
+  };
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_OPEN, iov_out);
+  FileDescriptor fd = ASSERT_NO_ERRNO_AND_VALUE(Open(test_file_path, O_RDWR));
+  SkipServerActualRequest();
+  ASSERT_THAT(close(fd.release()), SyscallSucceeds());
+
+  struct fuse_in_header in_header;
+  struct fuse_release_in in_payload;
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload);
+  GetServerActualRequest(iov_in);
+
+  EXPECT_EQ(in_header.len, sizeof(in_header) + sizeof(in_payload));
+  EXPECT_EQ(in_header.opcode, FUSE_RELEASE);
+  EXPECT_EQ(in_payload.flags, O_RDWR);
+  EXPECT_EQ(in_payload.fh, 1);
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor
diff --git a/test/fuse/linux/rmdir_test.cc b/test/fuse/linux/rmdir_test.cc
new file mode 100644
index 000000000..913d3f910
--- /dev/null
+++ b/test/fuse/linux/rmdir_test.cc
@@ -0,0 +1,73 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fuse.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "test/fuse/linux/fuse_base.h"
+#include "test/util/fs_util.h"
+#include "test/util/fuse_util.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+class RmDirTest : public FuseTest {
+ protected:
+  const std::string test_dir_name_ = "test_dir";
+  const mode_t test_dir_mode_ = S_IFDIR | S_IRWXU | S_IRWXG | S_IRWXO;
+};
+
+TEST_F(RmDirTest, NormalRmDir) {
+  const std::string test_dir_path_ =
+      JoinPath(mount_point_.path().c_str(), test_dir_name_);
+
+  SetServerInodeLookup(test_dir_name_, test_dir_mode_);
+
+  // RmDir code.
+  struct fuse_out_header rmdir_header = {
+      .len = sizeof(struct fuse_out_header),
+  };
+
+  auto iov_out = FuseGenerateIovecs(rmdir_header);
+  SetServerResponse(FUSE_RMDIR, iov_out);
+
+  ASSERT_THAT(rmdir(test_dir_path_.c_str()), SyscallSucceeds());
+
+  struct fuse_in_header in_header;
+  std::vector<char> actual_dirname(test_dir_name_.length() + 1);
+  auto iov_in = FuseGenerateIovecs(in_header, actual_dirname);
+  GetServerActualRequest(iov_in);
+
+  EXPECT_EQ(in_header.len, sizeof(in_header) + test_dir_name_.length() + 1);
+  EXPECT_EQ(in_header.opcode, FUSE_RMDIR);
+  EXPECT_EQ(std::string(actual_dirname.data()), test_dir_name_);
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor
diff --git a/test/fuse/linux/setstat_test.cc b/test/fuse/linux/setstat_test.cc
new file mode 100644
index 000000000..68301c775
--- /dev/null
+++ b/test/fuse/linux/setstat_test.cc
@@ -0,0 +1,338 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fuse.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <unistd.h>
+#include <utime.h>
+
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "test/fuse/linux/fuse_fd_util.h"
+#include "test/util/cleanup.h"
+#include "test/util/fs_util.h"
+#include "test/util/fuse_util.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+class SetStatTest : public FuseFdTest {
+ public:
+  void SetUp() override {
+    FuseFdTest::SetUp();
+    test_dir_path_ = JoinPath(mount_point_.path(), test_dir_);
+    test_file_path_ = JoinPath(mount_point_.path(), test_file_);
+  }
+
+ protected:
+  const uint64_t fh = 23;
+  const std::string test_dir_ = "testdir";
+  const std::string test_file_ = "testfile";
+  const mode_t test_dir_mode_ = S_IFDIR | S_IRUSR | S_IWUSR | S_IXUSR;
+  const mode_t test_file_mode_ = S_IFREG | S_IRUSR | S_IWUSR | S_IXUSR;
+
+  std::string test_dir_path_;
+  std::string test_file_path_;
+};
+
+TEST_F(SetStatTest, ChmodDir) {
+  // Set up fixture.
+  SetServerInodeLookup(test_dir_, test_dir_mode_);
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_attr_out),
+      .error = 0,
+  };
+  mode_t set_mode = S_IRGRP | S_IWGRP | S_IXGRP;
+  struct fuse_attr_out out_payload = {
+      .attr = DefaultFuseAttr(set_mode, 2),
+  };
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_SETATTR, iov_out);
+
+  // Make syscall.
+  EXPECT_THAT(chmod(test_dir_path_.c_str(), set_mode), SyscallSucceeds());
+
+  // Check FUSE request.
+  struct fuse_in_header in_header;
+  struct fuse_setattr_in in_payload;
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload);
+
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_header.len, sizeof(in_header) + sizeof(in_payload));
+  EXPECT_EQ(in_header.opcode, FUSE_SETATTR);
+  EXPECT_EQ(in_header.uid, 0);
+  EXPECT_EQ(in_header.gid, 0);
+  EXPECT_EQ(in_payload.valid, FATTR_MODE);
+  EXPECT_EQ(in_payload.mode, S_IFDIR | set_mode);
+}
+
+TEST_F(SetStatTest, ChownDir) {
+  // Set up fixture.
+  SetServerInodeLookup(test_dir_, test_dir_mode_);
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_attr_out),
+      .error = 0,
+  };
+  struct fuse_attr_out out_payload = {
+      .attr = DefaultFuseAttr(test_dir_mode_, 2),
+  };
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_SETATTR, iov_out);
+
+  // Make syscall.
+  EXPECT_THAT(chown(test_dir_path_.c_str(), 1025, 1025), SyscallSucceeds());
+
+  // Check FUSE request.
+  struct fuse_in_header in_header;
+  struct fuse_setattr_in in_payload;
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload);
+
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_header.len, sizeof(in_header) + sizeof(in_payload));
+  EXPECT_EQ(in_header.opcode, FUSE_SETATTR);
+  EXPECT_EQ(in_header.uid, 0);
+  EXPECT_EQ(in_header.gid, 0);
+  EXPECT_EQ(in_payload.valid, FATTR_UID | FATTR_GID);
+  EXPECT_EQ(in_payload.uid, 1025);
+  EXPECT_EQ(in_payload.gid, 1025);
+}
+
+TEST_F(SetStatTest, TruncateFile) {
+  // Set up fixture.
+  SetServerInodeLookup(test_file_, test_file_mode_);
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_attr_out),
+      .error = 0,
+  };
+  struct fuse_attr_out out_payload = {
+      .attr = DefaultFuseAttr(S_IFREG | S_IRUSR | S_IWUSR, 2),
+  };
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_SETATTR, iov_out);
+
+  // Make syscall.
+  EXPECT_THAT(truncate(test_file_path_.c_str(), 321), SyscallSucceeds());
+
+  // Check FUSE request.
+  struct fuse_in_header in_header;
+  struct fuse_setattr_in in_payload;
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload);
+
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_header.len, sizeof(in_header) + sizeof(in_payload));
+  EXPECT_EQ(in_header.opcode, FUSE_SETATTR);
+  EXPECT_EQ(in_header.uid, 0);
+  EXPECT_EQ(in_header.gid, 0);
+  EXPECT_EQ(in_payload.valid, FATTR_SIZE);
+  EXPECT_EQ(in_payload.size, 321);
+}
+
+TEST_F(SetStatTest, UtimeFile) {
+  // Set up fixture.
+  SetServerInodeLookup(test_file_, test_file_mode_);
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_attr_out),
+      .error = 0,
+  };
+  struct fuse_attr_out out_payload = {
+      .attr = DefaultFuseAttr(S_IFREG | S_IRUSR | S_IWUSR, 2),
+  };
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_SETATTR, iov_out);
+
+  // Make syscall.
+  time_t expected_atime = 1597159766, expected_mtime = 1597159765;
+  struct utimbuf times = {
+      .actime = expected_atime,
+      .modtime = expected_mtime,
+  };
+  EXPECT_THAT(utime(test_file_path_.c_str(), &times), SyscallSucceeds());
+
+  // Check FUSE request.
+  struct fuse_in_header in_header;
+  struct fuse_setattr_in in_payload;
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload);
+
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_header.len, sizeof(in_header) + sizeof(in_payload));
+  EXPECT_EQ(in_header.opcode, FUSE_SETATTR);
+  EXPECT_EQ(in_header.uid, 0);
+  EXPECT_EQ(in_header.gid, 0);
+  EXPECT_EQ(in_payload.valid, FATTR_ATIME | FATTR_MTIME);
+  EXPECT_EQ(in_payload.atime, expected_atime);
+  EXPECT_EQ(in_payload.mtime, expected_mtime);
+}
+
+TEST_F(SetStatTest, UtimesFile) {
+  // Set up fixture.
+  SetServerInodeLookup(test_file_, test_file_mode_);
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_attr_out),
+      .error = 0,
+  };
+  struct fuse_attr_out out_payload = {
+      .attr = DefaultFuseAttr(test_file_mode_, 2),
+  };
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_SETATTR, iov_out);
+
+  // Make syscall.
+  struct timeval expected_times[2] = {
+      {
+          .tv_sec = 1597159766,
+          .tv_usec = 234945,
+      },
+      {
+          .tv_sec = 1597159765,
+          .tv_usec = 232341,
+      },
+  };
+  EXPECT_THAT(utimes(test_file_path_.c_str(), expected_times),
+              SyscallSucceeds());
+
+  // Check FUSE request.
+  struct fuse_in_header in_header;
+  struct fuse_setattr_in in_payload;
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload);
+
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_header.len, sizeof(in_header) + sizeof(in_payload));
+  EXPECT_EQ(in_header.opcode, FUSE_SETATTR);
+  EXPECT_EQ(in_header.uid, 0);
+  EXPECT_EQ(in_header.gid, 0);
+  EXPECT_EQ(in_payload.valid, FATTR_ATIME | FATTR_MTIME);
+  EXPECT_EQ(in_payload.atime, expected_times[0].tv_sec);
+  EXPECT_EQ(in_payload.atimensec, expected_times[0].tv_usec * 1000);
+  EXPECT_EQ(in_payload.mtime, expected_times[1].tv_sec);
+  EXPECT_EQ(in_payload.mtimensec, expected_times[1].tv_usec * 1000);
+}
+
+TEST_F(SetStatTest, FtruncateFile) {
+  // Set up fixture.
+  SetServerInodeLookup(test_file_, test_file_mode_);
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenPath(test_file_path_, O_RDWR, fh));
+  auto close_fd = CloseFD(fd);
+
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_attr_out),
+      .error = 0,
+  };
+  struct fuse_attr_out out_payload = {
+      .attr = DefaultFuseAttr(test_file_mode_, 2),
+  };
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_SETATTR, iov_out);
+
+  // Make syscall.
+  EXPECT_THAT(ftruncate(fd.get(), 321), SyscallSucceeds());
+
+  // Check FUSE request.
+  struct fuse_in_header in_header;
+  struct fuse_setattr_in in_payload;
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload);
+
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_header.len, sizeof(in_header) + sizeof(in_payload));
+  EXPECT_EQ(in_header.opcode, FUSE_SETATTR);
+  EXPECT_EQ(in_header.uid, 0);
+  EXPECT_EQ(in_header.gid, 0);
+  EXPECT_EQ(in_payload.valid, FATTR_SIZE | FATTR_FH);
+  EXPECT_EQ(in_payload.fh, fh);
+  EXPECT_EQ(in_payload.size, 321);
+}
+
+TEST_F(SetStatTest, FchmodFile) {
+  // Set up fixture.
+  SetServerInodeLookup(test_file_, test_file_mode_);
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenPath(test_file_path_, O_RDWR, fh));
+  auto close_fd = CloseFD(fd);
+
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_attr_out),
+      .error = 0,
+  };
+  mode_t set_mode = S_IROTH | S_IWOTH | S_IXOTH;
+  struct fuse_attr_out out_payload = {
+      .attr = DefaultFuseAttr(set_mode, 2),
+  };
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_SETATTR, iov_out);
+
+  // Make syscall.
+  EXPECT_THAT(fchmod(fd.get(), set_mode), SyscallSucceeds());
+
+  // Check FUSE request.
+  struct fuse_in_header in_header;
+  struct fuse_setattr_in in_payload;
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload);
+
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_header.len, sizeof(in_header) + sizeof(in_payload));
+  EXPECT_EQ(in_header.opcode, FUSE_SETATTR);
+  EXPECT_EQ(in_header.uid, 0);
+  EXPECT_EQ(in_header.gid, 0);
+  EXPECT_EQ(in_payload.valid, FATTR_MODE | FATTR_FH);
+  EXPECT_EQ(in_payload.fh, fh);
+  EXPECT_EQ(in_payload.mode, S_IFREG | set_mode);
+}
+
+TEST_F(SetStatTest, FchownFile) {
+  // Set up fixture.
+  SetServerInodeLookup(test_file_, test_file_mode_);
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenPath(test_file_path_, O_RDWR, fh));
+  auto close_fd = CloseFD(fd);
+
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_attr_out),
+      .error = 0,
+  };
+  struct fuse_attr_out out_payload = {
+      .attr = DefaultFuseAttr(S_IFREG | S_IRUSR | S_IWUSR | S_IXUSR, 2),
+  };
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_SETATTR, iov_out);
+
+  // Make syscall.
+  EXPECT_THAT(fchown(fd.get(), 1025, 1025), SyscallSucceeds());
+
+  // Check FUSE request.
+  struct fuse_in_header in_header;
+  struct fuse_setattr_in in_payload;
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload);
+
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_header.len, sizeof(in_header) + sizeof(in_payload));
+  EXPECT_EQ(in_header.opcode, FUSE_SETATTR);
+  EXPECT_EQ(in_header.uid, 0);
+  EXPECT_EQ(in_header.gid, 0);
+  EXPECT_EQ(in_payload.valid, FATTR_UID | FATTR_GID | FATTR_FH);
+  EXPECT_EQ(in_payload.fh, fh);
+  EXPECT_EQ(in_payload.uid, 1025);
+  EXPECT_EQ(in_payload.gid, 1025);
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor
diff --git a/test/fuse/linux/stat_test.cc b/test/fuse/linux/stat_test.cc
index 172e09867..6f032cac1 100644
--- a/test/fuse/linux/stat_test.cc
+++ b/test/fuse/linux/stat_test.cc
@@ -18,12 +18,16 @@
 #include <sys/stat.h>
 #include <sys/statfs.h>
 #include <sys/types.h>
+#include <sys/uio.h>
 #include <unistd.h>
 
 #include <vector>
 
 #include "gtest/gtest.h"
-#include "test/fuse/linux/fuse_base.h"
+#include "test/fuse/linux/fuse_fd_util.h"
+#include "test/util/cleanup.h"
+#include "test/util/fs_util.h"
+#include "test/util/fuse_util.h"
 #include "test/util/test_util.h"
 
 namespace gvisor {
@@ -31,89 +35,45 @@ namespace testing {
 
 namespace {
 
-class StatTest : public FuseTest {
+class StatTest : public FuseFdTest {
  public:
-  bool CompareRequest(void* expected_mem, size_t expected_len, void* real_mem,
-                      size_t real_len) override {
-    if (expected_len != real_len) return false;
-    struct fuse_in_header* real_header =
-        reinterpret_cast<fuse_in_header*>(real_mem);
-
-    if (real_header->opcode != FUSE_GETATTR) {
-      std::cerr << "expect header opcode " << FUSE_GETATTR << " but got "
-                << real_header->opcode << std::endl;
-      return false;
-    }
-    return true;
+  void SetUp() override {
+    FuseFdTest::SetUp();
+    test_file_path_ = JoinPath(mount_point_.path(), test_file_);
   }
 
+ protected:
   bool StatsAreEqual(struct stat expected, struct stat actual) {
-    // device number will be dynamically allocated by kernel, we cannot know
-    // in advance
+    // Device number will be dynamically allocated by kernel, we cannot know in
+    // advance.
     actual.st_dev = expected.st_dev;
     return memcmp(&expected, &actual, sizeof(struct stat)) == 0;
   }
+
+  const std::string test_file_ = "testfile";
+  const mode_t expected_mode = S_IFREG | S_IRUSR | S_IWUSR;
+  const uint64_t fh = 23;
+
+  std::string test_file_path_;
 };
 
 TEST_F(StatTest, StatNormal) {
-  struct iovec iov_in[2];
-  struct iovec iov_out[2];
-
-  struct fuse_in_header in_header = {
-      .len = sizeof(struct fuse_in_header) + sizeof(struct fuse_getattr_in),
-      .opcode = FUSE_GETATTR,
-      .unique = 4,
-      .nodeid = 1,
-      .uid = 0,
-      .gid = 0,
-      .pid = 4,
-      .padding = 0,
-  };
-  struct fuse_getattr_in in_payload = {0};
-  iov_in[0].iov_len = sizeof(in_header);
-  iov_in[0].iov_base = &in_header;
-  iov_in[1].iov_len = sizeof(in_payload);
-  iov_in[1].iov_base = &in_payload;
-
-  mode_t expected_mode = S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH;
-  struct timespec atime = {.tv_sec = 1595436289, .tv_nsec = 134150844};
-  struct timespec mtime = {.tv_sec = 1595436290, .tv_nsec = 134150845};
-  struct timespec ctime = {.tv_sec = 1595436291, .tv_nsec = 134150846};
+  // Set up fixture.
+  struct fuse_attr attr = DefaultFuseAttr(expected_mode, 1);
   struct fuse_out_header out_header = {
       .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_attr_out),
-      .error = 0,
-      .unique = 4,
-  };
-  struct fuse_attr attr = {
-      .ino = 1,
-      .size = 512,
-      .blocks = 4,
-      .atime = static_cast<uint64_t>(atime.tv_sec),
-      .mtime = static_cast<uint64_t>(mtime.tv_sec),
-      .ctime = static_cast<uint64_t>(ctime.tv_sec),
-      .atimensec = static_cast<uint32_t>(atime.tv_nsec),
-      .mtimensec = static_cast<uint32_t>(mtime.tv_nsec),
-      .ctimensec = static_cast<uint32_t>(ctime.tv_nsec),
-      .mode = expected_mode,
-      .nlink = 2,
-      .uid = 1234,
-      .gid = 4321,
-      .rdev = 12,
-      .blksize = 4096,
   };
   struct fuse_attr_out out_payload = {
       .attr = attr,
   };
-  iov_out[0].iov_len = sizeof(out_header);
-  iov_out[0].iov_base = &out_header;
-  iov_out[1].iov_len = sizeof(out_payload);
-  iov_out[1].iov_base = &out_payload;
-
-  SetExpected(iov_in, 2, iov_out, 2);
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_GETATTR, iov_out);
 
+  // Make syscall.
   struct stat stat_buf;
   EXPECT_THAT(stat(mount_point_.path().c_str(), &stat_buf), SyscallSucceeds());
 
+  // Check filesystem operation result.
   struct stat expected_stat = {
       .st_ino = attr.ino,
       .st_nlink = attr.nlink,
@@ -124,43 +84,133 @@ TEST_F(StatTest, StatNormal) {
       .st_size = static_cast<off_t>(attr.size),
       .st_blksize = attr.blksize,
       .st_blocks = static_cast<blkcnt_t>(attr.blocks),
-      .st_atim = atime,
-      .st_mtim = mtime,
-      .st_ctim = ctime,
+      .st_atim = (struct timespec){.tv_sec = static_cast<int>(attr.atime),
+                                   .tv_nsec = attr.atimensec},
+      .st_mtim = (struct timespec){.tv_sec = static_cast<int>(attr.mtime),
+                                   .tv_nsec = attr.mtimensec},
+      .st_ctim = (struct timespec){.tv_sec = static_cast<int>(attr.ctime),
+                                   .tv_nsec = attr.ctimensec},
   };
   EXPECT_TRUE(StatsAreEqual(stat_buf, expected_stat));
-  WaitCompleted();
-}
 
-TEST_F(StatTest, StatNotFound) {
-  struct iovec iov_in[2];
-  struct iovec iov_out[2];
+  // Check FUSE request.
+  struct fuse_in_header in_header;
+  struct fuse_getattr_in in_payload;
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload);
 
-  struct fuse_in_header in_header = {
-      .len = sizeof(struct fuse_in_header) + sizeof(struct fuse_getattr_in),
-      .opcode = FUSE_GETATTR,
-      .unique = 4,
-  };
-  struct fuse_getattr_in in_payload = {0};
-  iov_in[0].iov_len = sizeof(in_header);
-  iov_in[0].iov_base = &in_header;
-  iov_in[1].iov_len = sizeof(in_payload);
-  iov_in[1].iov_base = &in_payload;
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_header.opcode, FUSE_GETATTR);
+  EXPECT_EQ(in_payload.getattr_flags, 0);
+  EXPECT_EQ(in_payload.fh, 0);
+}
 
+TEST_F(StatTest, StatNotFound) {
+  // Set up fixture.
   struct fuse_out_header out_header = {
       .len = sizeof(struct fuse_out_header),
       .error = -ENOENT,
-      .unique = 4,
   };
-  iov_out[0].iov_len = sizeof(out_header);
-  iov_out[0].iov_base = &out_header;
-
-  SetExpected(iov_in, 2, iov_out, 1);
+  auto iov_out = FuseGenerateIovecs(out_header);
+  SetServerResponse(FUSE_GETATTR, iov_out);
 
+  // Make syscall.
   struct stat stat_buf;
   EXPECT_THAT(stat(mount_point_.path().c_str(), &stat_buf),
               SyscallFailsWithErrno(ENOENT));
-  WaitCompleted();
+
+  // Check FUSE request.
+  struct fuse_in_header in_header;
+  struct fuse_getattr_in in_payload;
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload);
+
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_header.opcode, FUSE_GETATTR);
+  EXPECT_EQ(in_payload.getattr_flags, 0);
+  EXPECT_EQ(in_payload.fh, 0);
+}
+
+TEST_F(StatTest, FstatNormal) {
+  // Set up fixture.
+  SetServerInodeLookup(test_file_);
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenPath(test_file_path_, O_RDONLY, fh));
+  auto close_fd = CloseFD(fd);
+
+  struct fuse_attr attr = DefaultFuseAttr(expected_mode, 2);
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_attr_out),
+  };
+  struct fuse_attr_out out_payload = {
+      .attr = attr,
+  };
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_GETATTR, iov_out);
+
+  // Make syscall.
+  struct stat stat_buf;
+  EXPECT_THAT(fstat(fd.get(), &stat_buf), SyscallSucceeds());
+
+  // Check filesystem operation result.
+  struct stat expected_stat = {
+      .st_ino = attr.ino,
+      .st_nlink = attr.nlink,
+      .st_mode = expected_mode,
+      .st_uid = attr.uid,
+      .st_gid = attr.gid,
+      .st_rdev = attr.rdev,
+      .st_size = static_cast<off_t>(attr.size),
+      .st_blksize = attr.blksize,
+      .st_blocks = static_cast<blkcnt_t>(attr.blocks),
+      .st_atim = (struct timespec){.tv_sec = static_cast<int>(attr.atime),
+                                   .tv_nsec = attr.atimensec},
+      .st_mtim = (struct timespec){.tv_sec = static_cast<int>(attr.mtime),
+                                   .tv_nsec = attr.mtimensec},
+      .st_ctim = (struct timespec){.tv_sec = static_cast<int>(attr.ctime),
+                                   .tv_nsec = attr.ctimensec},
+  };
+  EXPECT_TRUE(StatsAreEqual(stat_buf, expected_stat));
+
+  // Check FUSE request.
+  struct fuse_in_header in_header;
+  struct fuse_getattr_in in_payload;
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload);
+
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_header.opcode, FUSE_GETATTR);
+  EXPECT_EQ(in_payload.getattr_flags, 0);
+  EXPECT_EQ(in_payload.fh, 0);
+}
+
+TEST_F(StatTest, StatByFileHandle) {
+  // Set up fixture.
+  SetServerInodeLookup(test_file_, expected_mode, 0);
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenPath(test_file_path_, O_RDONLY, fh));
+  auto close_fd = CloseFD(fd);
+
+  struct fuse_attr attr = DefaultFuseAttr(expected_mode, 2, 0);
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_attr_out),
+  };
+  struct fuse_attr_out out_payload = {
+      .attr = attr,
+  };
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_GETATTR, iov_out);
+
+  // Make syscall.
+  std::vector<char> buf(1);
+  // Since this is an empty file, it won't issue FUSE_READ. But a FUSE_GETATTR
+  // will be issued before read completes.
+  EXPECT_THAT(read(fd.get(), buf.data(), buf.size()), SyscallSucceeds());
+
+  // Check FUSE request.
+  struct fuse_in_header in_header;
+  struct fuse_getattr_in in_payload;
+  auto iov_in = FuseGenerateIovecs(in_header, in_payload);
+
+  GetServerActualRequest(iov_in);
+  EXPECT_EQ(in_header.opcode, FUSE_GETATTR);
+  EXPECT_EQ(in_payload.getattr_flags, FUSE_GETATTR_FH);
+  EXPECT_EQ(in_payload.fh, fh);
 }
 
 }  // namespace
diff --git a/test/fuse/linux/symlink_test.cc b/test/fuse/linux/symlink_test.cc
new file mode 100644
index 000000000..2c3a52987
--- /dev/null
+++ b/test/fuse/linux/symlink_test.cc
@@ -0,0 +1,88 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fuse.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "test/fuse/linux/fuse_base.h"
+#include "test/util/fuse_util.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+class SymlinkTest : public FuseTest {
+ protected:
+  const std::string target_file_ = "target_file_";
+  const std::string symlink_ = "symlink_";
+  const mode_t perms_ = S_IRWXU | S_IRWXG | S_IRWXO;
+};
+
+TEST_F(SymlinkTest, CreateSymLink) {
+  const std::string symlink_path =
+      JoinPath(mount_point_.path().c_str(), symlink_);
+
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_entry_out),
+  };
+  struct fuse_entry_out out_payload = DefaultEntryOut(S_IFLNK | perms_, 5);
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_SYMLINK, iov_out);
+  ASSERT_THAT(symlink(target_file_.c_str(), symlink_path.c_str()),
+              SyscallSucceeds());
+
+  struct fuse_in_header in_header;
+  std::vector<char> actual_target_file(target_file_.length() + 1);
+  std::vector<char> actual_symlink(symlink_.length() + 1);
+  auto iov_in =
+      FuseGenerateIovecs(in_header, actual_symlink, actual_target_file);
+  GetServerActualRequest(iov_in);
+
+  EXPECT_EQ(in_header.len,
+            sizeof(in_header) + symlink_.length() + target_file_.length() + 2);
+  EXPECT_EQ(in_header.opcode, FUSE_SYMLINK);
+  EXPECT_EQ(std::string(actual_target_file.data()), target_file_);
+  EXPECT_EQ(std::string(actual_symlink.data()), symlink_);
+}
+
+TEST_F(SymlinkTest, FileTypeError) {
+  const std::string symlink_path =
+      JoinPath(mount_point_.path().c_str(), symlink_);
+
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_entry_out),
+  };
+  struct fuse_entry_out out_payload = DefaultEntryOut(S_IFREG | perms_, 5);
+  auto iov_out = FuseGenerateIovecs(out_header, out_payload);
+  SetServerResponse(FUSE_SYMLINK, iov_out);
+  ASSERT_THAT(symlink(target_file_.c_str(), symlink_path.c_str()),
+              SyscallFailsWithErrno(EIO));
+  SkipServerActualRequest();
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor
diff --git a/test/fuse/linux/unlink_test.cc b/test/fuse/linux/unlink_test.cc
new file mode 100644
index 000000000..5702e9b32
--- /dev/null
+++ b/test/fuse/linux/unlink_test.cc
@@ -0,0 +1,83 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fuse.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "test/fuse/linux/fuse_base.h"
+#include "test/util/fuse_util.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+class UnlinkTest : public FuseTest {
+ protected:
+  const std::string test_file_ = "test_file";
+};
+
+TEST_F(UnlinkTest, RegularFile) {
+  const std::string test_file_path =
+      JoinPath(mount_point_.path().c_str(), test_file_);
+  SetServerInodeLookup(test_file_, S_IFREG | S_IRWXU | S_IRWXG | S_IRWXO);
+
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header),
+  };
+  auto iov_out = FuseGenerateIovecs(out_header);
+  SetServerResponse(FUSE_UNLINK, iov_out);
+
+  ASSERT_THAT(unlink(test_file_path.c_str()), SyscallSucceeds());
+  struct fuse_in_header in_header;
+  std::vector<char> unlinked_file(test_file_.length() + 1);
+  auto iov_in = FuseGenerateIovecs(in_header, unlinked_file);
+  GetServerActualRequest(iov_in);
+
+  EXPECT_EQ(in_header.len, sizeof(in_header) + test_file_.length() + 1);
+  EXPECT_EQ(in_header.opcode, FUSE_UNLINK);
+  EXPECT_EQ(std::string(unlinked_file.data()), test_file_);
+}
+
+TEST_F(UnlinkTest, NoFile) {
+  const std::string test_file_path =
+      JoinPath(mount_point_.path().c_str(), test_file_);
+  SetServerInodeLookup(test_file_, S_IFREG | S_IRWXU | S_IRWXG | S_IRWXO);
+
+  struct fuse_out_header out_header = {
+      .len = sizeof(struct fuse_out_header),
+      .error = -ENOENT,
+  };
+  auto iov_out = FuseGenerateIovecs(out_header);
+  SetServerResponse(FUSE_UNLINK, iov_out);
+
+  ASSERT_THAT(unlink(test_file_path.c_str()), SyscallFailsWithErrno(ENOENT));
+  SkipServerActualRequest();
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor
diff --git a/test/fuse/linux/write_test.cc b/test/fuse/linux/write_test.cc
new file mode 100644
index 000000000..1a62beb96
--- /dev/null
+++ b/test/fuse/linux/write_test.cc
@@ -0,0 +1,303 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/fuse.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+#include "gtest/gtest.h"
+#include "test/fuse/linux/fuse_base.h"
+#include "test/util/fuse_util.h"
+#include "test/util/test_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+class WriteTest : public FuseTest {
+  void SetUp() override {
+    FuseTest::SetUp();
+    test_file_path_ = JoinPath(mount_point_.path().c_str(), test_file_);
+  }
+
+  // TearDown overrides the parent's function
+  // to skip checking the unconsumed release request at the end.
+  void TearDown() override { UnmountFuse(); }
+
+ protected:
+  const std::string test_file_ = "test_file";
+  const mode_t test_file_mode_ = S_IFREG | S_IRWXU | S_IRWXG | S_IRWXO;
+  const uint64_t test_fh_ = 1;
+  const uint32_t open_flag_ = O_RDWR;
+
+  std::string test_file_path_;
+
+  PosixErrorOr<FileDescriptor> OpenTestFile(const std::string &path,
+                                            uint64_t size = 512) {
+    SetServerInodeLookup(test_file_, test_file_mode_, size);
+
+    struct fuse_out_header out_header_open = {
+        .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_open_out),
+    };
+    struct fuse_open_out out_payload_open = {
+        .fh = test_fh_,
+        .open_flags = open_flag_,
+    };
+    auto iov_out_open = FuseGenerateIovecs(out_header_open, out_payload_open);
+    SetServerResponse(FUSE_OPEN, iov_out_open);
+
+    auto res = Open(path.c_str(), open_flag_);
+    if (res.ok()) {
+      SkipServerActualRequest();
+    }
+    return res;
+  }
+};
+
+class WriteTestSmallMaxWrite : public WriteTest {
+  void SetUp() override {
+    MountFuse();
+    SetUpFuseServer(&fuse_init_payload);
+    test_file_path_ = JoinPath(mount_point_.path().c_str(), test_file_);
+  }
+
+ protected:
+  const static uint32_t max_write_ = 4096;
+  constexpr static struct fuse_init_out fuse_init_payload = {
+      .major = 7,
+      .max_write = max_write_,
+  };
+
+  const uint32_t size_fragment = max_write_;
+};
+
+TEST_F(WriteTest, WriteNormal) {
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_));
+
+  // Prepare for the write.
+  const int n_write = 10;
+  struct fuse_out_header out_header_write = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_write_out),
+  };
+  struct fuse_write_out out_payload_write = {
+      .size = n_write,
+  };
+  auto iov_out_write = FuseGenerateIovecs(out_header_write, out_payload_write);
+  SetServerResponse(FUSE_WRITE, iov_out_write);
+
+  // Issue the write.
+  std::vector<char> buf(n_write);
+  RandomizeBuffer(buf.data(), buf.size());
+  EXPECT_THAT(write(fd.get(), buf.data(), n_write),
+              SyscallSucceedsWithValue(n_write));
+
+  // Check the write request.
+  struct fuse_in_header in_header_write;
+  struct fuse_write_in in_payload_write;
+  std::vector<char> payload_buf(n_write);
+  auto iov_in_write =
+      FuseGenerateIovecs(in_header_write, in_payload_write, payload_buf);
+  GetServerActualRequest(iov_in_write);
+
+  EXPECT_EQ(in_payload_write.fh, test_fh_);
+  EXPECT_EQ(in_header_write.len,
+            sizeof(in_header_write) + sizeof(in_payload_write));
+  EXPECT_EQ(in_header_write.opcode, FUSE_WRITE);
+  EXPECT_EQ(in_payload_write.offset, 0);
+  EXPECT_EQ(in_payload_write.size, n_write);
+  EXPECT_EQ(buf, payload_buf);
+}
+
+TEST_F(WriteTest, WriteShort) {
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_));
+
+  // Prepare for the write.
+  const int n_write = 10, n_written = 5;
+  struct fuse_out_header out_header_write = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_write_out),
+  };
+  struct fuse_write_out out_payload_write = {
+      .size = n_written,
+  };
+  auto iov_out_write = FuseGenerateIovecs(out_header_write, out_payload_write);
+  SetServerResponse(FUSE_WRITE, iov_out_write);
+
+  // Issue the write.
+  std::vector<char> buf(n_write);
+  RandomizeBuffer(buf.data(), buf.size());
+  EXPECT_THAT(write(fd.get(), buf.data(), n_write),
+              SyscallSucceedsWithValue(n_written));
+
+  // Check the write request.
+  struct fuse_in_header in_header_write;
+  struct fuse_write_in in_payload_write;
+  std::vector<char> payload_buf(n_write);
+  auto iov_in_write =
+      FuseGenerateIovecs(in_header_write, in_payload_write, payload_buf);
+  GetServerActualRequest(iov_in_write);
+
+  EXPECT_EQ(in_payload_write.fh, test_fh_);
+  EXPECT_EQ(in_header_write.len,
+            sizeof(in_header_write) + sizeof(in_payload_write));
+  EXPECT_EQ(in_header_write.opcode, FUSE_WRITE);
+  EXPECT_EQ(in_payload_write.offset, 0);
+  EXPECT_EQ(in_payload_write.size, n_write);
+  EXPECT_EQ(buf, payload_buf);
+}
+
+TEST_F(WriteTest, WriteShortZero) {
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_));
+
+  // Prepare for the write.
+  const int n_write = 10;
+  struct fuse_out_header out_header_write = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_write_out),
+  };
+  struct fuse_write_out out_payload_write = {
+      .size = 0,
+  };
+  auto iov_out_write = FuseGenerateIovecs(out_header_write, out_payload_write);
+  SetServerResponse(FUSE_WRITE, iov_out_write);
+
+  // Issue the write.
+  std::vector<char> buf(n_write);
+  RandomizeBuffer(buf.data(), buf.size());
+  EXPECT_THAT(write(fd.get(), buf.data(), n_write), SyscallFailsWithErrno(EIO));
+
+  // Check the write request.
+  struct fuse_in_header in_header_write;
+  struct fuse_write_in in_payload_write;
+  std::vector<char> payload_buf(n_write);
+  auto iov_in_write =
+      FuseGenerateIovecs(in_header_write, in_payload_write, payload_buf);
+  GetServerActualRequest(iov_in_write);
+
+  EXPECT_EQ(in_payload_write.fh, test_fh_);
+  EXPECT_EQ(in_header_write.len,
+            sizeof(in_header_write) + sizeof(in_payload_write));
+  EXPECT_EQ(in_header_write.opcode, FUSE_WRITE);
+  EXPECT_EQ(in_payload_write.offset, 0);
+  EXPECT_EQ(in_payload_write.size, n_write);
+  EXPECT_EQ(buf, payload_buf);
+}
+
+TEST_F(WriteTest, WriteZero) {
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_));
+
+  // Issue the write.
+  std::vector<char> buf(0);
+  EXPECT_THAT(write(fd.get(), buf.data(), 0), SyscallSucceedsWithValue(0));
+}
+
+TEST_F(WriteTest, PWrite) {
+  const int file_size = 512;
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_, file_size));
+
+  // Prepare for the write.
+  const int n_write = 10;
+  struct fuse_out_header out_header_write = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_write_out),
+  };
+  struct fuse_write_out out_payload_write = {
+      .size = n_write,
+  };
+  auto iov_out_write = FuseGenerateIovecs(out_header_write, out_payload_write);
+  SetServerResponse(FUSE_WRITE, iov_out_write);
+
+  // Issue the write.
+  std::vector<char> buf(n_write);
+  RandomizeBuffer(buf.data(), buf.size());
+  const int offset_write = file_size >> 1;
+  EXPECT_THAT(pwrite(fd.get(), buf.data(), n_write, offset_write),
+              SyscallSucceedsWithValue(n_write));
+
+  // Check the write request.
+  struct fuse_in_header in_header_write;
+  struct fuse_write_in in_payload_write;
+  std::vector<char> payload_buf(n_write);
+  auto iov_in_write =
+      FuseGenerateIovecs(in_header_write, in_payload_write, payload_buf);
+  GetServerActualRequest(iov_in_write);
+
+  EXPECT_EQ(in_payload_write.fh, test_fh_);
+  EXPECT_EQ(in_header_write.len,
+            sizeof(in_header_write) + sizeof(in_payload_write));
+  EXPECT_EQ(in_header_write.opcode, FUSE_WRITE);
+  EXPECT_EQ(in_payload_write.offset, offset_write);
+  EXPECT_EQ(in_payload_write.size, n_write);
+  EXPECT_EQ(buf, payload_buf);
+}
+
+TEST_F(WriteTestSmallMaxWrite, WriteSmallMaxWrie) {
+  const int n_fragment = 10;
+  const int n_write = size_fragment * n_fragment;
+
+  auto fd = ASSERT_NO_ERRNO_AND_VALUE(OpenTestFile(test_file_path_, n_write));
+
+  // Prepare for the write.
+  struct fuse_out_header out_header_write = {
+      .len = sizeof(struct fuse_out_header) + sizeof(struct fuse_write_out),
+  };
+  struct fuse_write_out out_payload_write = {
+      .size = size_fragment,
+  };
+  auto iov_out_write = FuseGenerateIovecs(out_header_write, out_payload_write);
+
+  for (int i = 0; i < n_fragment; ++i) {
+    SetServerResponse(FUSE_WRITE, iov_out_write);
+  }
+
+  // Issue the write.
+  std::vector<char> buf(n_write);
+  RandomizeBuffer(buf.data(), buf.size());
+  EXPECT_THAT(write(fd.get(), buf.data(), n_write),
+              SyscallSucceedsWithValue(n_write));
+
+  ASSERT_EQ(GetServerNumUnsentResponses(), 0);
+  ASSERT_EQ(GetServerNumUnconsumedRequests(), n_fragment);
+
+  // Check the write request.
+  struct fuse_in_header in_header_write;
+  struct fuse_write_in in_payload_write;
+  std::vector<char> payload_buf(size_fragment);
+  auto iov_in_write =
+      FuseGenerateIovecs(in_header_write, in_payload_write, payload_buf);
+
+  for (int i = 0; i < n_fragment; ++i) {
+    GetServerActualRequest(iov_in_write);
+
+    EXPECT_EQ(in_payload_write.fh, test_fh_);
+    EXPECT_EQ(in_header_write.len,
+              sizeof(in_header_write) + sizeof(in_payload_write));
+    EXPECT_EQ(in_header_write.opcode, FUSE_WRITE);
+    EXPECT_EQ(in_payload_write.offset, i * size_fragment);
+    EXPECT_EQ(in_payload_write.size, size_fragment);
+
+    auto it = buf.begin() + i * size_fragment;
+    EXPECT_EQ(std::vector<char>(it, it + size_fragment), payload_buf);
+  }
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor
diff --git a/test/util/BUILD b/test/util/BUILD
index 2a17c33ee..fc5fb3a8d 100644
--- a/test/util/BUILD
+++ b/test/util/BUILD
@@ -46,6 +46,13 @@ cc_library(
 )
 
 cc_library(
+    name = "fuse_util",
+    testonly = 1,
+    srcs = ["fuse_util.cc"],
+    hdrs = ["fuse_util.h"],
+)
+
+cc_library(
     name = "proc_util",
     testonly = 1,
     srcs = ["proc_util.cc"],
diff --git a/test/util/fuse_util.cc b/test/util/fuse_util.cc
new file mode 100644
index 000000000..027f8386c
--- /dev/null
+++ b/test/util/fuse_util.cc
@@ -0,0 +1,63 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "test/util/fuse_util.h"
+
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <string>
+
+namespace gvisor {
+namespace testing {
+
+// Create a default FuseAttr struct with specified mode, inode, and size.
+fuse_attr DefaultFuseAttr(mode_t mode, uint64_t inode, uint64_t size) {
+  const int time_sec = 1595436289;
+  const int time_nsec = 134150844;
+  return (struct fuse_attr){
+      .ino = inode,
+      .size = size,
+      .blocks = 4,
+      .atime = time_sec,
+      .mtime = time_sec,
+      .ctime = time_sec,
+      .atimensec = time_nsec,
+      .mtimensec = time_nsec,
+      .ctimensec = time_nsec,
+      .mode = mode,
+      .nlink = 2,
+      .uid = 1234,
+      .gid = 4321,
+      .rdev = 12,
+      .blksize = 4096,
+  };
+}
+
+// Create response body with specified mode, nodeID, and size.
+fuse_entry_out DefaultEntryOut(mode_t mode, uint64_t node_id, uint64_t size) {
+  struct fuse_entry_out default_entry_out = {
+      .nodeid = node_id,
+      .generation = 0,
+      .entry_valid = 0,
+      .attr_valid = 0,
+      .entry_valid_nsec = 0,
+      .attr_valid_nsec = 0,
+      .attr = DefaultFuseAttr(mode, node_id, size),
+  };
+  return default_entry_out;
+}
+
+}  // namespace testing
+}  // namespace gvisor
diff --git a/test/util/fuse_util.h b/test/util/fuse_util.h
new file mode 100644
index 000000000..544fe1b38
--- /dev/null
+++ b/test/util/fuse_util.h
@@ -0,0 +1,75 @@
+// Copyright 2020 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef GVISOR_TEST_UTIL_FUSE_UTIL_H_
+#define GVISOR_TEST_UTIL_FUSE_UTIL_H_
+
+#include <linux/fuse.h>
+#include <sys/uio.h>
+
+#include <string>
+#include <vector>
+
+namespace gvisor {
+namespace testing {
+
+// The fundamental generation function with a single argument. If passed by
+// std::string or std::vector<char>, it will call specialized versions as
+// implemented below.
+template <typename T>
+std::vector<struct iovec> FuseGenerateIovecs(T &first) {
+  return {(struct iovec){.iov_base = &first, .iov_len = sizeof(first)}};
+}
+
+// If an argument is of type std::string, it must be used in read-only scenario.
+// Because we are setting up iovec, which contains the original address of a
+// data structure, we have to drop const qualification. Usually used with
+// variable-length payload data.
+template <typename T = std::string>
+std::vector<struct iovec> FuseGenerateIovecs(std::string &first) {
+  // Pad one byte for null-terminate c-string.
+  return {(struct iovec){.iov_base = const_cast<char *>(first.c_str()),
+                         .iov_len = first.size() + 1}};
+}
+
+// If an argument is of type std::vector<char>, it must be used in write-only
+// scenario and the size of the variable must be greater than or equal to the
+// size of the expected data. Usually used with variable-length payload data.
+template <typename T = std::vector<char>>
+std::vector<struct iovec> FuseGenerateIovecs(std::vector<char> &first) {
+  return {(struct iovec){.iov_base = first.data(), .iov_len = first.size()}};
+}
+
+// A helper function to set up an array of iovec struct for testing purpose.
+// Use variadic class template to generalize different numbers and different
+// types of FUSE structs.
+template <typename T, typename... Types>
+std::vector<struct iovec> FuseGenerateIovecs(T &first, Types &...args) {
+  auto first_iovec = FuseGenerateIovecs(first);
+  auto iovecs = FuseGenerateIovecs(args...);
+  first_iovec.insert(std::end(first_iovec), std::begin(iovecs),
+                     std::end(iovecs));
+  return first_iovec;
+}
+
+// Create a fuse_attr filled with the specified mode and inode.
+fuse_attr DefaultFuseAttr(mode_t mode, uint64_t inode, uint64_t size = 512);
+
+// Return a fuse_entry_out FUSE server response body.
+fuse_entry_out DefaultEntryOut(mode_t mode, uint64_t node_id,
+                               uint64_t size = 512);
+
+}  // namespace testing
+}  // namespace gvisor
+#endif  // GVISOR_TEST_UTIL_FUSE_UTIL_H_