nodefs: split out Operations interface in single-method interfaces

This is the prevalent style for FUSE libraries in Go.

nodefs/api.go

@@ -28,32 +28,34 @@
 // expressed through index-nodes (also known as "inode", see Inode) which
 // describe parent/child relation in between nodes and node-ID association.
 //
-// A particular filesystem should provide nodes with filesystem
-// operations implemented as defined by Operations interface. When
-// filesystem is mounted, its root Operations is associated with root
-// of the tree, and the tree is further build lazily when nodefs
-// infrastructure needs to lookup children of nodes to process client
-// requests. For every new Operations, the filesystem infrastructure
-// automatically builds new index node and links it in the filesystem
-// tree. Operations.Inode() can be used to get particular Inode
-// associated with a Operations.
+// All error reporting must use the syscall.Errno type. The value 0
+// (`OK`) should be used to indicate success. The method names are
+// inspired on the system call names, so we have Listxattr rather than
+// ListXAttr.
+//
+// A filesystem should provide nodes that embed InodeEmbed, so the
+// node comply with the InodeLink interface.  When filesystem is
+// mounted, its root InodeEmbed is associated with root of the tree,
+// and the tree is further built lazily when nodefs infrastructure
+// needs to lookup children of nodes to process client requests.
 //
 // The kernel can evict inode data to free up memory. It does so by
 // issuing FORGET calls. When a node has no children, and no kernel
 // references, it is removed from the file system trees.
 //
 // File system trees can also be constructed in advance. This is done
-// by instantiating "persistent" inodes from the Operations.OnAdd
-// method. Persistent inodes remain in memory even if the kernel has
-// forgotten them.  See zip_test.go for an example of how to do this.
+// by instantiating "persistent" inodes from the OnAdder
+// implementation. Persistent inodes remain in memory even if the
+// kernel has forgotten them.  See zip_test.go for an example of how
+// to do this.
 //
 // File systems whose tree structures are on backing storage typically
 // discover the file system tree on-demand, and if the kernel is tight
 // on memory, parts of the tree are forgotten again. These file
-// systems should implement Operations.Lookup instead.  The loopback
-// file system created by `NewLoopbackRoot` provides a straightforward
+// systems should implement Lookuper instead.  The loopback file
+// system created by `NewLoopbackRoot` provides a straightforward
 // example.
-//
+
 package nodefs
 
 import (
@@ -64,15 +66,20 @@ import (
 	"github.com/hanwen/go-fuse/fuse"
 )
 
-// InodeLink provides the machinery to connect Operations (user
-// defined methods) to Inode (a node in the filesystem tree).
+// InodeLink provides the machinery to connect user defined methods to
+// an Inode (a node in the filesystem tree).
+//
+// In general, if InodeLink does not implement specific filesystem
+// methods, the filesystem will react as if it is a read-only
+// filesystem with a predefined tree structure. See zipfs_test.go for
+// an example.  A example is in zip_test.go
 type InodeLink interface {
 	// populateInode and inode are used by nodefs internally to
 	// link Inode to a Node.
 	//
 	// See Inode() for the public API to retrieve an inode from Node.
 	inode() *Inode
-	init(ops Operations, attr NodeAttr, bridge *rawBridge, persistent bool)
+	init(ops InodeLink, attr NodeAttr, bridge *rawBridge, persistent bool)
 
 	// Inode returns the *Inode associated with this Operations
 	// instance.  The identity of the Inode does not change over
@@ -81,143 +88,162 @@ type InodeLink interface {
 	Inode() *Inode
 }
 
-// Operations is the interface that implements the filesystem inode.
-// Each Operations instance must embed OperationStubs. All error
-// reporting must use the syscall.Errno type. The value 0 (`OK`)
-// should be used to indicate success. The method names are inspired
-// on the system call names, so we have Listxattr rather than
-// ListXAttr.
-type Operations interface {
-	InodeLink
-
-	// Statfs implements statistics for the filesystem that holds
-	// this Inode.
+// Statfs implements statistics for the filesystem that holds this
+// Inode. If not defined, the `out` argument will zeroed with an OK
+// result.  This is because OSX filesystems must Statfs, or the mount
+// will not work.
+type Statfser interface {
 	Statfs(ctx context.Context, out *fuse.StatfsOut) syscall.Errno
+}
 
-	// Access should return if the caller can access the file with
-	// the given mode. In this case, the context has data about
-	// the real UID. For example a root-SUID binary called by user
-	// susan gets the UID and GID for susan here.
+// Access should return if the caller can access the file with
+// the given mode. In this case, the context has data about
+// the real UID. For example a root-SUID binary called by user
+// susan gets the UID and GID for susan here.
+//
+// If not defined, a default implementation will check traditional
+// unix permissions of the Getattr result agains the caller.
+type Accesser interface {
 	Access(ctx context.Context, mask uint32) syscall.Errno
+}
 
-	// GetAttr reads attributes for an Inode. The library will
-	// ensure that Mode and Ino are set correctly. For regular
-	// files, Size should be set so it can be read correctly.
+// GetAttr reads attributes for an Inode. The library will
+// ensure that Mode and Ino are set correctly. For regular
+// files, Size should be set so it can be read correctly.
+type Getattrer interface {
 	Getattr(ctx context.Context, out *fuse.AttrOut) syscall.Errno
+}
 
-	// SetAttr sets attributes for an Inode.
-	Setattr(ctx context.Context, in *fuse.SetAttrIn, out *fuse.AttrOut) syscall.Errno
+// SetAttr sets attributes for an Inode.
+type Setattrer interface {
+	Setattr(ctx context.Context, f FileHandle, in *fuse.SetAttrIn, out *fuse.AttrOut) syscall.Errno
+}
 
-	// OnAdd is called once this Operations object is attached to
-	// an Inode.
+// OnAdd is called once this Operations object is attached to
+// an Inode.
+type OnAdder interface {
 	OnAdd(ctx context.Context)
 }
 
-// XAttrOperations is a collection of methods used to implement extended attributes.
-type XAttrOperations interface {
-	Operations
-
-	// GetXAttr should read data for the given attribute into
-	// `dest` and return the number of bytes. If `dest` is too
-	// small, it should return ERANGE and the size of the attribute.
+// Getxattr should read data for the given attribute into
+// `dest` and return the number of bytes. If `dest` is too
+// small, it should return ERANGE and the size of the attribute.
+// If not defined, Getxattr will return ENOATTR.
+type Getxattrer interface {
 	Getxattr(ctx context.Context, attr string, dest []byte) (uint32, syscall.Errno)
+}
 
-	// SetXAttr should store data for the given attribute.  See
-	// setxattr(2) for information about flags.
+// Setxattr should store data for the given attribute.  See
+// setxattr(2) for information about flags.
+// If not defined, Setxattr will return ENOATTR.
+type Setxattrer interface {
 	Setxattr(ctx context.Context, attr string, data []byte, flags uint32) syscall.Errno
+}
 
-	// RemoveXAttr should delete the given attribute.
+// Removexattr should delete the given attribute.
+// If not defined, Removexattr will return ENOATTR.
+type Removexattrer interface {
 	Removexattr(ctx context.Context, attr string) syscall.Errno
+}
 
-	// ListXAttr should read all attributes (null terminated) into
-	// `dest`. If the `dest` buffer is too small, it should return
-	// ERANGE and the correct size.
+// Listxattr should read all attributes (null terminated) into
+// `dest`. If the `dest` buffer is too small, it should return ERANGE
+// and the correct size.  If not defined, return an empty list and
+// success.
+type Listxattrer interface {
 	Listxattr(ctx context.Context, dest []byte) (uint32, syscall.Errno)
 }
 
-// SymlinkOperations holds operations specific to symlinks.
-type SymlinkOperations interface {
-	Operations
-
-	// Readlink reads the content of a symlink.
+// Readlink reads the content of a symlink.
+type Readlinker interface {
 	Readlink(ctx context.Context) ([]byte, syscall.Errno)
 }
 
-// FileOperations holds operations that apply to regular files.
-type FileOperations interface {
-	Operations
-
-	// Open opens an Inode (of regular file type) for reading. It
-	// is optional but recommended to return a FileHandle.
+// Open opens an Inode (of regular file type) for reading. It
+// is optional but recommended to return a FileHandle.
+type Opener interface {
 	Open(ctx context.Context, flags uint32) (fh FileHandle, fuseFlags uint32, errno syscall.Errno)
+}
 
-	// Reads data from a file. The data should be returned as
-	// ReadResult, which may be constructed from the incoming
-	// `dest` buffer. If the file was opened without FileHandle,
-	// the FileHandle argument here is nil. The default
-	// implementation forwards to the FileHandle.
+// Reads data from a file. The data should be returned as
+// ReadResult, which may be constructed from the incoming
+// `dest` buffer. If the file was opened without FileHandle,
+// the FileHandle argument here is nil. The default
+// implementation forwards to the FileHandle.
+type Reader interface {
 	Read(ctx context.Context, f FileHandle, dest []byte, off int64) (fuse.ReadResult, syscall.Errno)
+}
 
-	// Writes the data into the file handle at given offset. After
-	// returning, the data will be reused and may not referenced.
-	// The default implementation forwards to the FileHandle.
+// Writes the data into the file handle at given offset. After
+// returning, the data will be reused and may not referenced.
+// The default implementation forwards to the FileHandle.
+type Writer interface {
 	Write(ctx context.Context, f FileHandle, data []byte, off int64) (written uint32, errno syscall.Errno)
+}
 
-	// Fsync is a signal to ensure writes to the Inode are flushed
-	// to stable storage.  The default implementation forwards to the
-	// FileHandle.
+// Fsync is a signal to ensure writes to the Inode are flushed
+// to stable storage.
+type Fsyncer interface {
 	Fsync(ctx context.Context, f FileHandle, flags uint32) syscall.Errno
+}
 
-	// Flush is called for close() call on a file descriptor. In
-	// case of duplicated descriptor, it may be called more than
-	// once for a file.   The default implementation forwards to the
-	// FileHandle.
+// Flush is called for close() call on a file descriptor. In
+// case of duplicated descriptor, it may be called more than
+// once for a file.   The default implementation forwards to the
+// FileHandle.
+type Flusher interface {
 	Flush(ctx context.Context, f FileHandle) syscall.Errno
+}
 
-	// This is called to before the file handle is forgotten. The
-	// kernel ingores the return value of this method,
-	// so any cleanup that requires specific synchronization or
-	// could fail with I/O errors should happen in Flush instead.
-	// The default implementation forwards to the FileHandle.
+// This is called to before the file handle is forgotten. The
+// kernel ingores the return value of this method,
+// so any cleanup that requires specific synchronization or
+// could fail with I/O errors should happen in Flush instead.
+// The default implementation forwards to the FileHandle.
+type Releaser interface {
 	Release(ctx context.Context, f FileHandle) syscall.Errno
+}
 
-	// Allocate preallocates space for future writes, so they will
-	// never encounter ESPACE.
+// Allocate preallocates space for future writes, so they will
+// never encounter ESPACE.
+type Allocater interface {
 	Allocate(ctx context.Context, f FileHandle, off uint64, size uint64, mode uint32) syscall.Errno
+}
 
-	// FGetattr is like Getattr but provides a file handle if available.
-	Fgetattr(ctx context.Context, f FileHandle, out *fuse.AttrOut) syscall.Errno
-
-	// FSetattr is like SetAttr but provides a file handle if available.
-	Fsetattr(ctx context.Context, f FileHandle, in *fuse.SetAttrIn, out *fuse.AttrOut) syscall.Errno
-
-	// CopyFileRange copies data between sections of two files,
-	// without the data having to pass through the calling process.
+// CopyFileRange copies data between sections of two files,
+// without the data having to pass through the calling process.
+type CopyFileRanger interface {
 	CopyFileRange(ctx context.Context, fhIn FileHandle,
 		offIn uint64, out *Inode, fhOut FileHandle, offOut uint64,
 		len uint64, flags uint64) (uint32, syscall.Errno)
+}
 
-	// Lseek is used to implement holes: it should return the
-	// first offset beyond `off` where there is data (SEEK_DATA)
-	// or where there is a hole (SEEK_HOLE).
+// Lseek is used to implement holes: it should return the
+// first offset beyond `off` where there is data (SEEK_DATA)
+// or where there is a hole (SEEK_HOLE).
+type Lseeker interface {
 	Lseek(ctx context.Context, f FileHandle, Off uint64, whence uint32) (uint64, syscall.Errno)
 }
 
 // LockOperations are operations for locking regions of regular files.
-type LockOperations interface {
-	FileOperations
-
-	// Getlk returns locks that would conflict with the given
-	// input lock. If no locks conflict, the output has type
-	// L_UNLCK. See fcntl(2) for more information.
+// Getlk returns locks that would conflict with the given input
+// lock. If no locks conflict, the output has type L_UNLCK. See
+// fcntl(2) for more information.
+// If not defined, returns ENOTSUP
+type Getlker interface {
 	Getlk(ctx context.Context, f FileHandle, owner uint64, lk *fuse.FileLock, flags uint32, out *fuse.FileLock) syscall.Errno
+}
 
-	// Setlk obtains a lock on a file, or fail if the lock could not
-	// obtained.  See fcntl(2) for more information.
+// Setlk obtains a lock on a file, or fail if the lock could not
+// obtained.  See fcntl(2) for more information.  If not defined,
+// returns ENOTSUP
+type Setlker interface {
 	Setlk(ctx context.Context, f FileHandle, owner uint64, lk *fuse.FileLock, flags uint32) syscall.Errno
+}
 
-	// Setlkw obtains a lock on a file, waiting if necessary. See fcntl(2)
-	// for more information.
+// Setlkw obtains a lock on a file, waiting if necessary. See fcntl(2)
+// for more information.  If not defined, returns ENOTSUP
+type Setlkwer interface {
 	Setlkw(ctx context.Context, f FileHandle, owner uint64, lk *fuse.FileLock, flags uint32) syscall.Errno
 }
 
@@ -237,63 +263,87 @@ type DirStream interface {
 	Close()
 }
 
-// DirOperations are operations for directory nodes in the filesystem.
-type DirOperations interface {
-	Operations
-
-	// Lookup should find a direct child of the node by child
-	// name.  If the entry does not exist, it should return ENOENT
-	// and optionally set a NegativeTimeout in `out`. If it does
-	// exist, it should return attribute data in `out` and return
-	// the Inode for the child. A new inode can be created using
-	// `Inode.NewInode`. The new Inode will be added to the FS
-	// tree automatically if the return status is OK.
+// Lookup should find a direct child of the node by child
+// name.  If the entry does not exist, it should return ENOENT
+// and optionally set a NegativeTimeout in `out`. If it does
+// exist, it should return attribute data in `out` and return
+// the Inode for the child. A new inode can be created using
+// `Inode.NewInode`. The new Inode will be added to the FS
+// tree automatically if the return status is OK.
+//
+// If not defined, we look for an existing child with the given name,
+// or returns ENOENT.
+type Lookuper interface {
 	Lookup(ctx context.Context, name string, out *fuse.EntryOut) (*Inode, syscall.Errno)
+}
 
-	// OpenDir opens a directory Inode for reading its
-	// contents. The actual reading is driven from ReadDir, so
-	// this method is just for performing sanity/permission
-	// checks.
+// OpenDir opens a directory Inode for reading its
+// contents. The actual reading is driven from ReadDir, so
+// this method is just for performing sanity/permission
+// checks. The default is to return success.
+type Opendirer interface {
 	Opendir(ctx context.Context) syscall.Errno
+}
 
-	// ReadDir opens a stream of directory entries.
+// ReadDir opens a stream of directory entries.
+//
+// The default ReadDir returns the list of currently known children
+// from the tree
+type Readdirer interface {
 	Readdir(ctx context.Context) (DirStream, syscall.Errno)
 }
 
-// MutableDirOperations are operations for directories that can add or
-// remove entries.
-type MutableDirOperations interface {
-	DirOperations
-
-	// Mkdir is similar to Lookup, but must create a directory entry and Inode.
+// Mkdir is similar to Lookup, but must create a directory entry and Inode.
+// Default is to return EROFS.
+type Mkdirer interface {
 	Mkdir(ctx context.Context, name string, mode uint32, out *fuse.EntryOut) (*Inode, syscall.Errno)
+}
 
-	// Mknod is similar to Lookup, but must create a device entry and Inode.
+// Mknod is similar to Lookup, but must create a device entry and Inode.
+// Default is to return EROFS.
+type Mknoder interface {
 	Mknod(ctx context.Context, name string, mode uint32, dev uint32, out *fuse.EntryOut) (*Inode, syscall.Errno)
+}
 
-	// Link is similar to Lookup, but must create a new link to an existing Inode.
-	Link(ctx context.Context, target Operations, name string, out *fuse.EntryOut) (node *Inode, errno syscall.Errno)
+// Link is similar to Lookup, but must create a new link to an existing Inode.
+// Default is to return EROFS.
+type Linker interface {
+	Link(ctx context.Context, target InodeLink, name string, out *fuse.EntryOut) (node *Inode, errno syscall.Errno)
+}
 
-	// Symlink is similar to Lookup, but must create a new symbolic link.
+// Symlink is similar to Lookup, but must create a new symbolic link.
+// Default is to return EROFS.
+type Symlinker interface {
 	Symlink(ctx context.Context, target, name string, out *fuse.EntryOut) (node *Inode, errno syscall.Errno)
+}
 
-	// Create is similar to Lookup, but should create a new
-	// child. It typically also returns a FileHandle as a
-	// reference for future reads/writes
+// Create is similar to Lookup, but should create a new
+// child. It typically also returns a FileHandle as a
+// reference for future reads/writes.
+// Default is to return EROFS.
+type Creater interface {
 	Create(ctx context.Context, name string, flags uint32, mode uint32) (node *Inode, fh FileHandle, fuseFlags uint32, errno syscall.Errno)
+}
 
-	// Unlink should remove a child from this directory.  If the
-	// return status is OK, the Inode is removed as child in the
-	// FS tree automatically.
+// Unlink should remove a child from this directory.  If the
+// return status is OK, the Inode is removed as child in the
+// FS tree automatically. Default is to return EROFS.
+type Unlinker interface {
 	Unlink(ctx context.Context, name string) syscall.Errno
+}
 
-	// Rmdir is like Unlink but for directories.
+// Rmdir is like Unlink but for directories.
+// Default is to return EROFS.
+type Rmdirer interface {
 	Rmdir(ctx context.Context, name string) syscall.Errno
+}
 
-	// Rename should move a child from one directory to a
-	// different one. The changes is effected in the FS tree if
-	// the return status is OK
-	Rename(ctx context.Context, name string, newParent Operations, newName string, flags uint32) syscall.Errno
+// Rename should move a child from one directory to a different
+// one. The change is effected in the FS tree if the return status is
+// OK.
+// Default is to return EROFS.
+type Renamer interface {
+	Rename(ctx context.Context, name string, newParent InodeLink, newName string, flags uint32) syscall.Errno
 }
 
 // FileHandle is a resource identifier for opened files.  FileHandles
@@ -307,28 +357,67 @@ type MutableDirOperations interface {
 // FileHandle. Files that have such dynamic content should return the
 // FOPEN_DIRECT_IO flag from their `Open` method. See directio_test.go
 // for an example.
-//
-// For a description of individual operations, see the equivalent
-// operations in FileOperations.
 type FileHandle interface {
+}
+
+// Release is called when forgetting the file handle. Default is to
+// call Release on the Inode.
+type FileReleaser interface {
+	Release(ctx context.Context) syscall.Errno
+}
+
+// See Getattrer. Default is to call Getattr on the Inode
+type FileGetattrer interface {
+	Getattr(ctx context.Context, out *fuse.AttrOut) syscall.Errno
+}
+
+// See Reader. Default is to call Read on the Inode
+type FileReader interface {
 	Read(ctx context.Context, dest []byte, off int64) (fuse.ReadResult, syscall.Errno)
+}
 
+// See Writer. Default is to call Write on the Inode
+type FileWriter interface {
 	Write(ctx context.Context, data []byte, off int64) (written uint32, errno syscall.Errno)
+}
 
+// See Getlker. Default is to call Getlk on the Inode
+type FileGetlker interface {
 	Getlk(ctx context.Context, owner uint64, lk *fuse.FileLock, flags uint32, out *fuse.FileLock) syscall.Errno
+}
+
+// See Setlker. Default is to call Setlk on the Inode
+type FileSetlker interface {
 	Setlk(ctx context.Context, owner uint64, lk *fuse.FileLock, flags uint32) syscall.Errno
+}
+
+// See Setlkwer. Default is to call Setlkw on the Inode
+type FileSetlkwer interface {
 	Setlkw(ctx context.Context, owner uint64, lk *fuse.FileLock, flags uint32) syscall.Errno
+}
 
+// See Lseek. Default is to call Lseek on the Inode
+type FileLseeker interface {
 	Lseek(ctx context.Context, off uint64, whence uint32) (uint64, syscall.Errno)
+}
 
+// See Flusher. Default is to call Flush on the Inode
+type FileFlusher interface {
 	Flush(ctx context.Context) syscall.Errno
+}
 
+// See Fsync. Default is to call Fsync on the Inode
+type FileFsyncer interface {
 	Fsync(ctx context.Context, flags uint32) syscall.Errno
+}
 
-	Release(ctx context.Context) syscall.Errno
-
-	Getattr(ctx context.Context, out *fuse.AttrOut) syscall.Errno
+// See Fsync. Default is to call Setattr on the Inode
+type FileSetattrer interface {
 	Setattr(ctx context.Context, in *fuse.SetAttrIn, out *fuse.AttrOut) syscall.Errno
+}
+
+// See Allocater. Default is to call Allocate on the Inode
+type FileAllocater interface {
 	Allocate(ctx context.Context, off uint64, size uint64, mode uint32) syscall.Errno
 }
 

nodefs/bridge.go

@@ -12,6 +12,7 @@ import (
 	"time"
 
 	"github.com/hanwen/go-fuse/fuse"
+	"github.com/hanwen/go-fuse/internal"
 )
 
 func errnoToStatus(errno syscall.Errno) fuse.Status {
@@ -48,7 +49,7 @@ type rawBridge struct {
 }
 
 // newInode creates creates new inode pointing to ops.
-func (b *rawBridge) newInode(ctx context.Context, ops Operations, id NodeAttr, persistent bool) *Inode {
+func (b *rawBridge) newInode(ctx context.Context, ops InodeLink, id NodeAttr, persistent bool) *Inode {
 	b.mu.Lock()
 	defer b.mu.Unlock()
 
@@ -93,26 +94,11 @@ func (b *rawBridge) newInode(ctx context.Context, ops Operations, id NodeAttr, p
 		id.Mode = fuse.S_IFREG
 	}
 
-	switch id.Mode {
-	case fuse.S_IFDIR:
-		_ = ops.(DirOperations)
-	case fuse.S_IFLNK:
-		_ = ops.(SymlinkOperations)
-	case fuse.S_IFREG:
-		_ = ops.(FileOperations)
-	case fuse.S_IFIFO, syscall.S_IFSOCK:
-		// no type check necessary: FIFO and SOCK don't go
-		// through FUSE for open/read etc.
-		break
-	default:
-		// Remaining types are char and block devices.  Not
-		// sure how those would work in FUSE
-		log.Panicf("filetype %o unimplemented", id.Mode)
-	}
-
 	b.nodes[id.Ino] = ops.inode()
 	ops.init(ops, id, b, persistent)
-	ops.OnAdd(ctx)
+	if oa, ok := ops.(OnAdder); ok {
+		oa.OnAdd(ctx)
+	}
 	return ops.inode()
 }
 
@@ -155,7 +141,7 @@ func (b *rawBridge) setAttrTimeout(out *fuse.AttrOut) {
 
 // NewNodeFS creates a node based filesystem based on an Operations
 // instance for the root.
-func NewNodeFS(root DirOperations, opts *Options) fuse.RawFileSystem {
+func NewNodeFS(root InodeLink, opts *Options) fuse.RawFileSystem {
 	bridge := &rawBridge{
 		automaticIno: opts.FirstAutomaticIno,
 	}
@@ -192,7 +178,9 @@ func NewNodeFS(root DirOperations, opts *Options) fuse.RawFileSystem {
 	// Fh 0 means no file handle.
 	bridge.files = []*fileEntry{{}}
 
-	root.OnAdd(context.Background())
+	if oa, ok := root.(OnAdder); ok {
+		oa.OnAdd(context.Background())
+	}
 
 	return bridge
 }
@@ -213,8 +201,9 @@ func (b *rawBridge) inode(id uint64, fh uint64) (*Inode, *fileEntry) {
 
 func (b *rawBridge) Lookup(cancel <-chan struct{}, header *fuse.InHeader, name string, out *fuse.EntryOut) fuse.Status {
 	parent, _ := b.inode(header.NodeId, 0)
+	ctx := &fuse.Context{Caller: header.Caller, Cancel: cancel}
+	child, errno := b.lookup(ctx, parent, name, out)
 
-	child, errno := parent.dirOps().Lookup(&fuse.Context{Caller: header.Caller, Cancel: cancel}, name, out)
 	if errno != 0 {
 		if b.options.NegativeTimeout != nil && out.EntryTimeout() == 0 {
 			out.SetEntryTimeout(*b.options.NegativeTimeout)
@@ -226,13 +215,35 @@ func (b *rawBridge) Lookup(cancel <-chan struct{}, header *fuse.InHeader, name s
 	b.setEntryOutTimeout(out)
 
 	out.Mode = child.nodeAttr.Mode | (out.Mode & 07777)
+
 	return fuse.OK
 }
 
+func (b *rawBridge) lookup(ctx *fuse.Context, parent *Inode, name string, out *fuse.EntryOut) (*Inode, syscall.Errno) {
+	if lu, ok := parent.ops.(Lookuper); ok {
+		return lu.Lookup(ctx, name, out)
+	}
+
+	child := parent.GetChild(name)
+	if child == nil {
+		return nil, syscall.ENOENT
+	}
+
+	if ga, ok := child.ops.(Getattrer); ok {
+		var a fuse.AttrOut
+		errno := ga.Getattr(ctx, &a)
+		if errno == 0 {
+			out.Attr = a.Attr
+		}
+	}
+
+	return child, OK
+}
+
 func (b *rawBridge) Rmdir(cancel <-chan struct{}, header *fuse.InHeader, name string) fuse.Status {
 	parent, _ := b.inode(header.NodeId, 0)
 	var errno syscall.Errno
-	if mops, ok := parent.ops.(MutableDirOperations); ok {
+	if mops, ok := parent.ops.(Rmdirer); ok {
 		errno = mops.Rmdir(&fuse.Context{Caller: header.Caller, Cancel: cancel}, name)
 	}
 
@@ -245,7 +256,7 @@ func (b *rawBridge) Rmdir(cancel <-chan struct{}, header *fuse.InHeader, name st
 func (b *rawBridge) Unlink(cancel <-chan struct{}, header *fuse.InHeader, name string) fuse.Status {
 	parent, _ := b.inode(header.NodeId, 0)
 	var errno syscall.Errno
-	if mops, ok := parent.ops.(MutableDirOperations); ok {
+	if mops, ok := parent.ops.(Unlinker); ok {
 		errno = mops.Unlink(&fuse.Context{Caller: header.Caller, Cancel: cancel}, name)
 	}
 
@@ -260,7 +271,7 @@ func (b *rawBridge) Mkdir(cancel <-chan struct{}, input *fuse.MkdirIn, name stri
 
 	var child *Inode
 	var errno syscall.Errno
-	if mops, ok := parent.ops.(MutableDirOperations); ok {
+	if mops, ok := parent.ops.(Mkdirer); ok {
 		child, errno = mops.Mkdir(&fuse.Context{Caller: input.Caller, Cancel: cancel}, name, input.Mode, out)
 	}
 
@@ -282,7 +293,7 @@ func (b *rawBridge) Mknod(cancel <-chan struct{}, input *fuse.MknodIn, name stri
 
 	var child *Inode
 	var errno syscall.Errno
-	if mops, ok := parent.ops.(MutableDirOperations); ok {
+	if mops, ok := parent.ops.(Mknoder); ok {
 		child, errno = mops.Mknod(&fuse.Context{Caller: input.Caller, Cancel: cancel}, name, input.Mode, input.Rdev, out)
 	}
 
@@ -303,7 +314,7 @@ func (b *rawBridge) Create(cancel <-chan struct{}, input *fuse.CreateIn, name st
 	var errno syscall.Errno
 	var f FileHandle
 	var flags uint32
-	if mops, ok := parent.ops.(MutableDirOperations); ok {
+	if mops, ok := parent.ops.(Creater); ok {
 		child, f, flags, errno = mops.Create(ctx, name, input.Flags, input.Mode)
 	}
 
@@ -315,20 +326,17 @@ func (b *rawBridge) Create(cancel <-chan struct{}, input *fuse.CreateIn, name st
 	}
 
 	out.Fh = uint64(b.addNewChild(parent, name, child, f, input.Flags|syscall.O_CREAT, &out.EntryOut))
-	b.setEntryOutTimeout(&out.EntryOut)
 
 	out.OpenFlags = flags
 
 	var temp fuse.AttrOut
-	f.Getattr(ctx, &temp)
+	b.getattr(ctx, child, f, &temp)
 	out.Attr = temp.Attr
 	out.AttrValid = temp.AttrValid
 	out.AttrValidNsec = temp.AttrValidNsec
-	out.Attr.Ino = child.nodeAttr.Ino
-	out.Generation = child.nodeAttr.Gen
-	out.NodeId = child.nodeAttr.Ino
 
 	b.setEntryOutTimeout(&out.EntryOut)
+	out.NodeId = child.nodeAttr.Ino
 	out.Mode = (out.Attr.Mode & 07777) | child.nodeAttr.Mode
 	return fuse.OK
 }
@@ -342,11 +350,8 @@ func (b *rawBridge) SetDebug(debug bool) {}
 
 func (b *rawBridge) GetAttr(cancel <-chan struct{}, input *fuse.GetAttrIn, out *fuse.AttrOut) fuse.Status {
 	n, fEntry := b.inode(input.NodeId, input.Fh())
-	ctx := &fuse.Context{Caller: input.Caller, Cancel: cancel}
-	if fops, ok := n.ops.(FileOperations); ok {
-
 	f := fEntry.file
-		if input.Flags()&fuse.FUSE_GETATTR_FH == 0 {
+	if f == nil {
 		// The linux kernel doesnt pass along the file
 		// descriptor, so we have to fake it here.
 		// See https://github.com/libfuse/libfuse/issues/62
@@ -359,14 +364,32 @@ func (b *rawBridge) GetAttr(cancel <-chan struct{}, input *fuse.GetAttrIn, out *
 		}
 		b.mu.Unlock()
 	}
+	ctx := &fuse.Context{Caller: input.Caller, Cancel: cancel}
+	return errnoToStatus(b.getattr(ctx, n, f, out))
+}
+
+func (b *rawBridge) getattr(ctx context.Context, n *Inode, f FileHandle, out *fuse.AttrOut) syscall.Errno {
+	var errno syscall.Errno
+
+	var fg FileGetattrer
+	if f != nil {
+		fg, _ = f.(FileGetattrer)
+	}
+
+	if fg != nil {
+		errno = fg.Getattr(ctx, out)
+	} else if fops, ok := n.ops.(Getattrer); ok {
+		errno = fops.Getattr(ctx, out)
+	} else {
+		// We set Mode below, which is the minimum for success
+	}
 
-		errno := fops.Fgetattr(ctx, f, out)
+	if errno == 0 {
 		b.setAttrTimeout(out)
-		out.Ino = input.NodeId
+		out.Ino = n.nodeAttr.Ino
 		out.Mode = (out.Attr.Mode & 07777) | n.nodeAttr.Mode
-		return errnoToStatus(errno)
 	}
-	return errnoToStatus(n.ops.Getattr(ctx, out))
+	return errno
 }
 
 func (b *rawBridge) SetAttr(cancel <-chan struct{}, in *fuse.SetAttrIn, out *fuse.AttrOut) fuse.Status {
@@ -378,18 +401,22 @@ func (b *rawBridge) SetAttr(cancel <-chan struct{}, in *fuse.SetAttrIn, out *fus
 		f = nil
 	}
 
-	if fops, ok := n.ops.(FileOperations); ok {
-		return errnoToStatus(fops.Fsetattr(ctx, f, in, out))
+	if fops, ok := f.(FileSetattrer); ok {
+		return errnoToStatus(fops.Setattr(ctx, in, out))
 	}
 
-	return errnoToStatus(n.ops.Setattr(ctx, in, out))
+	if fops, ok := n.ops.(Setattrer); ok {
+		return errnoToStatus(fops.Setattr(ctx, f, in, out))
+	}
+
+	return fuse.ENOTSUP
 }
 
 func (b *rawBridge) Rename(cancel <-chan struct{}, input *fuse.RenameIn, oldName string, newName string) fuse.Status {
 	p1, _ := b.inode(input.NodeId, 0)
 	p2, _ := b.inode(input.Newdir, 0)
 
-	if mops, ok := p1.ops.(MutableDirOperations); ok {
+	if mops, ok := p1.ops.(Renamer); ok {
 		errno := mops.Rename(&fuse.Context{Caller: input.Caller, Cancel: cancel}, oldName, p2.ops, newName, input.Flags)
 		if errno == 0 {
 			if input.Flags&RENAME_EXCHANGE != 0 {
@@ -408,7 +435,7 @@ func (b *rawBridge) Link(cancel <-chan struct{}, input *fuse.LinkIn, name string
 	parent, _ := b.inode(input.NodeId, 0)
 	target, _ := b.inode(input.Oldnodeid, 0)
 
-	if mops, ok := parent.ops.(MutableDirOperations); ok {
+	if mops, ok := parent.ops.(Linker); ok {
 		child, errno := mops.Link(&fuse.Context{Caller: input.Caller, Cancel: cancel}, target.ops, name, out)
 		if errno != 0 {
 			return errnoToStatus(errno)
@@ -424,7 +451,7 @@ func (b *rawBridge) Link(cancel <-chan struct{}, input *fuse.LinkIn, name string
 func (b *rawBridge) Symlink(cancel <-chan struct{}, header *fuse.InHeader, target string, name string, out *fuse.EntryOut) fuse.Status {
 	parent, _ := b.inode(header.NodeId, 0)
 
-	if mops, ok := parent.ops.(MutableDirOperations); ok {
+	if mops, ok := parent.ops.(Symlinker); ok {
 		child, status := mops.Symlink(&fuse.Context{Caller: header.Caller, Cancel: cancel}, target, name, out)
 		if status != 0 {
 			return errnoToStatus(status)
@@ -439,17 +466,45 @@ func (b *rawBridge) Symlink(cancel <-chan struct{}, header *fuse.InHeader, targe
 
 func (b *rawBridge) Readlink(cancel <-chan struct{}, header *fuse.InHeader) (out []byte, status fuse.Status) {
 	n, _ := b.inode(header.NodeId, 0)
-	result, errno := n.linkOps().Readlink(&fuse.Context{Caller: header.Caller, Cancel: cancel})
+
+	if linker, ok := n.ops.(Readlinker); ok {
+		result, errno := linker.Readlink(&fuse.Context{Caller: header.Caller, Cancel: cancel})
 		if errno != 0 {
 			return nil, errnoToStatus(errno)
 		}
 
 		return result, fuse.OK
+
+	}
+
+	return nil, fuse.ENOTSUP
 }
 
 func (b *rawBridge) Access(cancel <-chan struct{}, input *fuse.AccessIn) fuse.Status {
 	n, _ := b.inode(input.NodeId, 0)
-	return errnoToStatus(n.ops.Access(&fuse.Context{Caller: input.Caller, Cancel: cancel}, input.Mask))
+
+	ctx := &fuse.Context{Caller: input.Caller, Cancel: cancel}
+	if a, ok := n.ops.(Accesser); ok {
+		return errnoToStatus(a.Access(ctx, input.Mask))
+	}
+
+	// default: check attributes.
+	caller := input.Caller
+
+	ga, ok := n.ops.(Getattrer)
+	if !ok {
+		return fuse.EACCES
+	}
+
+	var out fuse.AttrOut
+	if s := ga.Getattr(ctx, &out); s != 0 {
+		return errnoToStatus(s)
+	}
+
+	if !internal.HasAccess(caller.Uid, caller.Gid, out.Uid, out.Gid, out.Mode, input.Mask) {
+		return fuse.EACCES
+	}
+	return fuse.OK
 }
 
 // Extended attributes.
@@ -457,42 +512,44 @@ func (b *rawBridge) Access(cancel <-chan struct{}, input *fuse.AccessIn) fuse.St
 func (b *rawBridge) GetXAttr(cancel <-chan struct{}, header *fuse.InHeader, attr string, data []byte) (uint32, fuse.Status) {
 	n, _ := b.inode(header.NodeId, 0)
 
-	if xops, ok := n.ops.(XAttrOperations); ok {
+	if xops, ok := n.ops.(Getxattrer); ok {
 		nb, errno := xops.Getxattr(&fuse.Context{Caller: header.Caller, Cancel: cancel}, attr, data)
 		return nb, errnoToStatus(errno)
 	}
 
-	return 0, fuse.ENOTSUP
+	return 0, fuse.ENOATTR
 }
 
 func (b *rawBridge) ListXAttr(cancel <-chan struct{}, header *fuse.InHeader, dest []byte) (sz uint32, status fuse.Status) {
 	n, _ := b.inode(header.NodeId, 0)
-	if xops, ok := n.ops.(XAttrOperations); ok {
+	if xops, ok := n.ops.(Listxattrer); ok {
 		sz, errno := xops.Listxattr(&fuse.Context{Caller: header.Caller, Cancel: cancel}, dest)
 		return sz, errnoToStatus(errno)
 	}
-	return 0, fuse.ENOTSUP
+	return 0, fuse.OK
 }
 
 func (b *rawBridge) SetXAttr(cancel <-chan struct{}, input *fuse.SetXAttrIn, attr string, data []byte) fuse.Status {
 	n, _ := b.inode(input.NodeId, 0)
-	if xops, ok := n.ops.(XAttrOperations); ok {
+	if xops, ok := n.ops.(Setxattrer); ok {
 		return errnoToStatus(xops.Setxattr(&fuse.Context{Caller: input.Caller, Cancel: cancel}, attr, data, input.Flags))
 	}
-	return fuse.ENOTSUP
+	return fuse.ENOATTR
 }
 
 func (b *rawBridge) RemoveXAttr(cancel <-chan struct{}, header *fuse.InHeader, attr string) fuse.Status {
 	n, _ := b.inode(header.NodeId, 0)
-	if xops, ok := n.ops.(XAttrOperations); ok {
+	if xops, ok := n.ops.(Removexattrer); ok {
 		return errnoToStatus(xops.Removexattr(&fuse.Context{Caller: header.Caller, Cancel: cancel}, attr))
 	}
-	return fuse.ENOTSUP
+	return fuse.ENOATTR
 }
 
 func (b *rawBridge) Open(cancel <-chan struct{}, input *fuse.OpenIn, out *fuse.OpenOut) fuse.Status {
 	n, _ := b.inode(input.NodeId, 0)
-	f, flags, errno := n.fileOps().Open(&fuse.Context{Caller: input.Caller, Cancel: cancel}, input.Flags)
+
+	if op, ok := n.ops.(Opener); ok {
+		f, flags, errno := op.Open(&fuse.Context{Caller: input.Caller, Cancel: cancel}, input.Flags)
 		if errno != 0 {
 			return errnoToStatus(errno)
 		}
@@ -504,6 +561,9 @@ func (b *rawBridge) Open(cancel <-chan struct{}, input *fuse.OpenIn, out *fuse.O
 		}
 		out.OpenFlags = flags
 		return fuse.OK
+	}
+
+	return fuse.ENOTSUP
 }
 
 // registerFile hands out a file handle. Must have bridge.mu
@@ -528,14 +588,26 @@ func (b *rawBridge) registerFile(n *Inode, f FileHandle, flags uint32) uint32 {
 
 func (b *rawBridge) Read(cancel <-chan struct{}, input *fuse.ReadIn, buf []byte) (fuse.ReadResult, fuse.Status) {
 	n, f := b.inode(input.NodeId, input.Fh)
-	res, errno := n.fileOps().Read(&fuse.Context{Caller: input.Caller, Cancel: cancel}, f.file, buf, int64(input.Offset))
+
+	if fr, ok := f.file.(FileReader); ok {
+		res, errno := fr.Read(&fuse.Context{Caller: input.Caller, Cancel: cancel}, buf, int64(input.Offset))
+		return res, errnoToStatus(errno)
+	}
+
+	if fops, ok := n.ops.(Reader); ok {
+		res, errno := fops.Read(&fuse.Context{Caller: input.Caller, Cancel: cancel}, f.file, buf, int64(input.Offset))
 		return res, errnoToStatus(errno)
+	}
+	return nil, fuse.ENOTSUP
 }
 
 func (b *rawBridge) GetLk(cancel <-chan struct{}, input *fuse.LkIn, out *fuse.LkOut) fuse.Status {
 	n, f := b.inode(input.NodeId, input.Fh)
 
-	if lops, ok := n.ops.(LockOperations); ok {
+	if gl, ok := f.file.(FileGetlker); ok {
+		return errnoToStatus(gl.Getlk(&fuse.Context{Caller: input.Caller, Cancel: cancel}, input.Owner, &input.Lk, input.LkFlags, &out.Lk))
+	}
+	if lops, ok := n.ops.(Getlker); ok {
 		return errnoToStatus(lops.Getlk(&fuse.Context{Caller: input.Caller, Cancel: cancel}, f.file, input.Owner, &input.Lk, input.LkFlags, &out.Lk))
 	}
 	return fuse.ENOTSUP
@@ -543,14 +615,20 @@ func (b *rawBridge) GetLk(cancel <-chan struct{}, input *fuse.LkIn, out *fuse.Lk
 
 func (b *rawBridge) SetLk(cancel <-chan struct{}, input *fuse.LkIn) fuse.Status {
 	n, f := b.inode(input.NodeId, input.Fh)
-	if lops, ok := n.ops.(LockOperations); ok {
+	if sl, ok := n.ops.(FileSetlker); ok {
+		return errnoToStatus(sl.Setlk(&fuse.Context{Caller: input.Caller, Cancel: cancel}, input.Owner, &input.Lk, input.LkFlags))
+	}
+	if lops, ok := n.ops.(Setlker); ok {
 		return errnoToStatus(lops.Setlk(&fuse.Context{Caller: input.Caller, Cancel: cancel}, f.file, input.Owner, &input.Lk, input.LkFlags))
 	}
 	return fuse.ENOTSUP
 }
 func (b *rawBridge) SetLkw(cancel <-chan struct{}, input *fuse.LkIn) fuse.Status {
 	n, f := b.inode(input.NodeId, input.Fh)
-	if lops, ok := n.ops.(LockOperations); ok {
+	if sl, ok := n.ops.(FileSetlkwer); ok {
+		return errnoToStatus(sl.Setlkw(&fuse.Context{Caller: input.Caller, Cancel: cancel}, input.Owner, &input.Lk, input.LkFlags))
+	}
+	if lops, ok := n.ops.(Setlkwer); ok {
 		return errnoToStatus(lops.Setlkw(&fuse.Context{Caller: input.Caller, Cancel: cancel}, f.file, input.Owner, &input.Lk, input.LkFlags))
 	}
 	return fuse.ENOTSUP
@@ -563,7 +641,12 @@ func (b *rawBridge) Release(cancel <-chan struct{}, input *fuse.ReleaseIn) {
 	}
 
 	f.wg.Wait()
-	n.fileOps().Release(&fuse.Context{Caller: input.Caller, Cancel: cancel}, f.file)
+
+	if r, ok := n.ops.(Releaser); ok {
+		r.Release(&fuse.Context{Caller: input.Caller, Cancel: cancel}, f.file)
+	} else if r, ok := f.file.(FileReleaser); ok {
+		r.Release(&fuse.Context{Caller: input.Caller, Cancel: cancel})
+	}
 
 	b.mu.Lock()
 	defer b.mu.Unlock()
@@ -604,44 +687,75 @@ func (b *rawBridge) releaseFileEntry(nid uint64, fh uint64) (*Inode, *fileEntry)
 func (b *rawBridge) Write(cancel <-chan struct{}, input *fuse.WriteIn, data []byte) (written uint32, status fuse.Status) {
 	n, f := b.inode(input.NodeId, input.Fh)
 
-	w, errno := n.fileOps().Write(&fuse.Context{Caller: input.Caller, Cancel: cancel}, f.file, data, int64(input.Offset))
+	if fr, ok := f.file.(FileWriter); ok {
+		w, errno := fr.Write(&fuse.Context{Caller: input.Caller, Cancel: cancel}, data, int64(input.Offset))
+		return w, errnoToStatus(errno)
+	}
+
+	if wr, ok := n.ops.(Writer); ok {
+		w, errno := wr.Write(&fuse.Context{Caller: input.Caller, Cancel: cancel}, f.file, data, int64(input.Offset))
 		return w, errnoToStatus(errno)
+	}
+
+	return 0, fuse.ENOTSUP
 }
 
 func (b *rawBridge) Flush(cancel <-chan struct{}, input *fuse.FlushIn) fuse.Status {
 	n, f := b.inode(input.NodeId, input.Fh)
-	return errnoToStatus(n.fileOps().Flush(&fuse.Context{Caller: input.Caller, Cancel: cancel}, f.file))
+	if fl, ok := f.file.(FileFlusher); ok {
+		return errnoToStatus(fl.Flush(&fuse.Context{Caller: input.Caller, Cancel: cancel}))
+	}
+	if fl, ok := n.ops.(Flusher); ok {
+		return errnoToStatus(fl.Flush(&fuse.Context{Caller: input.Caller, Cancel: cancel}, f.file))
+	}
+	return fuse.ENOTSUP
 }
 
 func (b *rawBridge) Fsync(cancel <-chan struct{}, input *fuse.FsyncIn) fuse.Status {
 	n, f := b.inode(input.NodeId, input.Fh)
-	return errnoToStatus(n.fileOps().Fsync(&fuse.Context{Caller: input.Caller, Cancel: cancel}, f.file, input.FsyncFlags))
+	if fs, ok := f.file.(FileFsyncer); ok {
+		return errnoToStatus(fs.Fsync(&fuse.Context{Caller: input.Caller, Cancel: cancel}, input.FsyncFlags))
+	}
+	if fs, ok := n.ops.(Fsyncer); ok {
+		return errnoToStatus(fs.Fsync(&fuse.Context{Caller: input.Caller, Cancel: cancel}, f.file, input.FsyncFlags))
+	}
+	return fuse.ENOTSUP
 }
 
 func (b *rawBridge) Fallocate(cancel <-chan struct{}, input *fuse.FallocateIn) fuse.Status {
 	n, f := b.inode(input.NodeId, input.Fh)
-	return errnoToStatus(n.fileOps().Allocate(&fuse.Context{Caller: input.Caller, Cancel: cancel}, f.file, input.Offset, input.Length, input.Mode))
+	if a, ok := n.ops.(FileAllocater); ok {
+		return errnoToStatus(a.Allocate(&fuse.Context{Caller: input.Caller, Cancel: cancel}, input.Offset, input.Length, input.Mode))
+	}
+	if a, ok := n.ops.(Allocater); ok {
+		return errnoToStatus(a.Allocate(&fuse.Context{Caller: input.Caller, Cancel: cancel}, f.file, input.Offset, input.Length, input.Mode))
+	}
+	return fuse.ENOTSUP
 }
 
 func (b *rawBridge) OpenDir(cancel <-chan struct{}, input *fuse.OpenIn, out *fuse.OpenOut) fuse.Status {
 	n, _ := b.inode(input.NodeId, 0)
-	errno := n.dirOps().Opendir(&fuse.Context{Caller: input.Caller, Cancel: cancel})
+
+	if od, ok := n.ops.(Opendirer); ok {
+		errno := od.Opendir(&fuse.Context{Caller: input.Caller, Cancel: cancel})
 		if errno != 0 {
 			return errnoToStatus(errno)
 		}
+	}
+
 	b.mu.Lock()
 	defer b.mu.Unlock()
 	out.Fh = uint64(b.registerFile(n, nil, 0))
 	return fuse.OK
 }
 
-func (b *rawBridge) getStream(cancel <-chan struct{}, input *fuse.ReadIn, inode *Inode, f *fileEntry) syscall.Errno {
+func (b *rawBridge) setStream(cancel <-chan struct{}, input *fuse.ReadIn, inode *Inode, f *fileEntry) syscall.Errno {
 	if f.dirStream == nil || input.Offset == 0 {
 		if f.dirStream != nil {
 			f.dirStream.Close()
 			f.dirStream = nil
 		}
-		str, errno := inode.dirOps().Readdir(&fuse.Context{Caller: input.Caller, Cancel: cancel})
+		str, errno := b.getStream(&fuse.Context{Caller: input.Caller, Cancel: cancel}, inode)
 		if errno != 0 {
 			return errno
 		}
@@ -653,10 +767,25 @@ func (b *rawBridge) getStream(cancel <-chan struct{}, input *fuse.ReadIn, inode
 	return 0
 }
 
+func (b *rawBridge) getStream(ctx context.Context, inode *Inode) (DirStream, syscall.Errno) {
+	rd, ok := inode.ops.(Readdirer)
+	if !ok {
+		r := []fuse.DirEntry{}
+		for k, ch := range inode.Children() {
+			r = append(r, fuse.DirEntry{Mode: ch.Mode(),
+				Name: k,
+				Ino:  ch.NodeAttr().Ino})
+		}
+		return NewListDirStream(r), 0
+	}
+
+	return rd.Readdir(ctx)
+}
+
 func (b *rawBridge) ReadDir(cancel <-chan struct{}, input *fuse.ReadIn, out *fuse.DirEntryList) fuse.Status {
 	n, f := b.inode(input.NodeId, input.Fh)
 
-	if errno := b.getStream(cancel, input, n, f); errno != 0 {
+	if errno := b.setStream(cancel, input, n, f); errno != 0 {
 		return errnoToStatus(errno)
 	}
 
@@ -685,10 +814,10 @@ func (b *rawBridge) ReadDir(cancel <-chan struct{}, input *fuse.ReadIn, out *fus
 func (b *rawBridge) ReadDirPlus(cancel <-chan struct{}, input *fuse.ReadIn, out *fuse.DirEntryList) fuse.Status {
 	n, f := b.inode(input.NodeId, input.Fh)
 
-	if errno := b.getStream(cancel, input, n, f); errno != 0 {
+	if errno := b.setStream(cancel, input, n, f); errno != 0 {
 		return errnoToStatus(errno)
 	}
-
+	ctx := &fuse.Context{Caller: input.Caller, Cancel: cancel}
 	for f.dirStream.HasNext() {
 		var e fuse.DirEntry
 		var errno syscall.Errno
@@ -710,7 +839,7 @@ func (b *rawBridge) ReadDirPlus(cancel <-chan struct{}, input *fuse.ReadIn, out
 			return fuse.OK
 		}
 
-		child, errno := n.dirOps().Lookup(&fuse.Context{Caller: input.Caller, Cancel: cancel}, e.Name, entryOut)
+		child, errno := b.lookup(ctx, n, e.Name, entryOut)
 		if errno != 0 {
 			if b.options.NegativeTimeout != nil {
 				entryOut.SetEntryTimeout(*b.options.NegativeTimeout)
@@ -732,12 +861,21 @@ func (b *rawBridge) ReadDirPlus(cancel <-chan struct{}, input *fuse.ReadIn, out
 
 func (b *rawBridge) FsyncDir(cancel <-chan struct{}, input *fuse.FsyncIn) fuse.Status {
 	n, _ := b.inode(input.NodeId, input.Fh)
-	return errnoToStatus(n.fileOps().Fsync(&fuse.Context{Caller: input.Caller, Cancel: cancel}, nil, input.FsyncFlags))
+	if fs, ok := n.ops.(Fsyncer); ok {
+		return errnoToStatus(fs.Fsync(&fuse.Context{Caller: input.Caller, Cancel: cancel}, nil, input.FsyncFlags))
+	}
+
+	return fuse.ENOTSUP
 }
 
 func (b *rawBridge) StatFs(cancel <-chan struct{}, input *fuse.InHeader, out *fuse.StatfsOut) fuse.Status {
 	n, _ := b.inode(input.NodeId, 0)
-	return errnoToStatus(n.ops.Statfs(&fuse.Context{Caller: input.Caller, Cancel: cancel}, out))
+	if sf, ok := n.ops.(Statfser); ok {
+		return errnoToStatus(sf.Statfs(&fuse.Context{Caller: input.Caller, Cancel: cancel}, out))
+	}
+
+	// leave zeroed out
+	return fuse.OK
 }
 
 func (b *rawBridge) Init(s *fuse.Server) {
@@ -746,9 +884,14 @@ func (b *rawBridge) Init(s *fuse.Server) {
 
 func (b *rawBridge) CopyFileRange(cancel <-chan struct{}, in *fuse.CopyFileRangeIn) (size uint32, status fuse.Status) {
 	n1, f1 := b.inode(in.NodeId, in.FhIn)
+	cfr, ok := n1.ops.(CopyFileRanger)
+	if !ok {
+		return 0, fuse.ENOTSUP
+	}
+
 	n2, f2 := b.inode(in.NodeIdOut, in.FhOut)
 
-	sz, errno := n1.fileOps().CopyFileRange(&fuse.Context{Caller: in.Caller, Cancel: cancel},
+	sz, errno := cfr.CopyFileRange(&fuse.Context{Caller: in.Caller, Cancel: cancel},
 		f1.file, in.OffIn, n2, f2.file, in.OffOut, in.Len, in.Flags)
 	return sz, errnoToStatus(errno)
 }
@@ -756,8 +899,24 @@ func (b *rawBridge) CopyFileRange(cancel <-chan struct{}, in *fuse.CopyFileRange
 func (b *rawBridge) Lseek(cancel <-chan struct{}, in *fuse.LseekIn, out *fuse.LseekOut) fuse.Status {
 	n, f := b.inode(in.NodeId, in.Fh)
 
-	off, errno := n.fileOps().Lseek(&fuse.Context{Caller: in.Caller, Cancel: cancel},
+	if fs, ok := f.file.(FileLseeker); ok {
+		off, errno := fs.Lseek(&fuse.Context{Caller: in.Caller, Cancel: cancel}, in.Offset, in.Whence)
+		out.Offset = off
+		return errnoToStatus(errno)
+	}
+
+	ls, ok := n.ops.(Lseeker)
+	if ok {
+		off, errno := ls.Lseek(&fuse.Context{Caller: in.Caller, Cancel: cancel},
 			f.file, in.Offset, in.Whence)
 		out.Offset = off
 		return errnoToStatus(errno)
+	}
+
+	if in.Whence == _SEEK_DATA || in.Whence == _SEEK_HOLE {
+		out.Offset = in.Offset
+		return fuse.OK
+	}
+
+	return fuse.ENOTSUP
 }

nodefs/cache_test.go

@@ -19,7 +19,7 @@ import (
 )
 
 type keepCacheFile struct {
-	OperationStubs
+	InodeEmbed
 	keepCache bool
 
 	mu      sync.Mutex
@@ -61,12 +61,18 @@ func (f *keepCacheFile) Read(ctx context.Context, fh FileHandle, dest []byte, of
 	return fuse.ReadResultData(f.content[off:]), OK
 }
 
+var _ = (Reader)((*keepCacheFile)(nil))
+var _ = (Opener)((*keepCacheFile)(nil))
+var _ = (Getattrer)((*keepCacheFile)(nil))
+
 type keepCacheRoot struct {
-	OperationStubs
+	InodeEmbed
 
 	keep, nokeep *keepCacheFile
 }
 
+var _ = (OnAdder)((*keepCacheRoot)(nil))
+
 func (r *keepCacheRoot) OnAdd(ctx context.Context) {
 	i := r.Inode()
 

nodefs/default.go

@@ -5,11 +5,7 @@
 package nodefs
 
 import (
-	"context"
-	"syscall"
-
 	"github.com/hanwen/go-fuse/fuse"
-	"github.com/hanwen/go-fuse/internal"
 )
 
 // InodeEmbed embeds the Inode into a filesystem node. It is the only
@@ -25,7 +21,7 @@ func (n *InodeEmbed) inode() *Inode {
 	return &n.inode_
 }
 
-func (n *InodeEmbed) init(ops Operations, attr NodeAttr, bridge *rawBridge, persistent bool) {
+func (n *InodeEmbed) init(ops InodeLink, attr NodeAttr, bridge *rawBridge, persistent bool) {
 	n.inode_ = Inode{
 		ops:        ops,
 		nodeAttr:   attr,
@@ -42,332 +38,3 @@ func (n *InodeEmbed) init(ops Operations, attr NodeAttr, bridge *rawBridge, pers
 func (n *InodeEmbed) Inode() *Inode {
 	return &n.inode_
 }
-
-// OperationStubs provides no-operation default implementations for
-// all the XxxOperations interfaces. The stubs provide useful defaults
-// for implementing a read-only filesystem whose tree is constructed
-// beforehand in the OnAdd method of the root. A example is in
-// zip_test.go
-//
-// It is recommended to embed this in any Operations implementation,
-// as it is the means by new operations are supported.
-type OperationStubs struct {
-	InodeEmbed
-}
-
-// check that we have implemented all interface methods
-var _ DirOperations = &OperationStubs{}
-var _ FileOperations = &OperationStubs{}
-var _ LockOperations = &OperationStubs{}
-
-// StatFs zeroes the out argument and returns OK.  This is because OSX
-// filesystems must define this, or the mount will not work.
-func (n *OperationStubs) Statfs(ctx context.Context, out *fuse.StatfsOut) syscall.Errno {
-	// this should be defined on OSX, or the FS won't mount
-	*out = fuse.StatfsOut{}
-	return OK
-}
-
-// The default OnAdd does nothing.
-func (n *OperationStubs) OnAdd(ctx context.Context) {
-}
-
-// GetAttr zeroes out argument and returns OK.
-func (n *OperationStubs) Getattr(ctx context.Context, out *fuse.AttrOut) syscall.Errno {
-	*out = fuse.AttrOut{}
-	return OK
-}
-
-func (n *OperationStubs) Setattr(ctx context.Context, in *fuse.SetAttrIn, out *fuse.AttrOut) syscall.Errno {
-	return syscall.EROFS
-}
-
-// The Access default implementation checks traditional unix
-// permissions of the GetAttr result agains the caller.
-func (n *OperationStubs) Access(ctx context.Context, mask uint32) syscall.Errno {
-	caller, ok := fuse.FromContext(ctx)
-	if !ok {
-		return syscall.EINVAL
-	}
-
-	var out fuse.AttrOut
-	if s := n.inode().Operations().Getattr(ctx, &out); s != 0 {
-		return s
-	}
-
-	if !internal.HasAccess(caller.Uid, caller.Gid, out.Uid, out.Gid, out.Mode, mask) {
-		return syscall.EACCES
-	}
-	return OK
-}
-
-// FSetAttr delegates to the FileHandle's if f is not nil, or else to the
-// Inode's SetAttr method.
-func (n *OperationStubs) Fsetattr(ctx context.Context, f FileHandle, in *fuse.SetAttrIn, out *fuse.AttrOut) syscall.Errno {
-	if f != nil {
-		return f.Setattr(ctx, in, out)
-	}
-
-	return n.inode_.Operations().Setattr(ctx, in, out)
-}
-
-// The Lookup method on the OperationStubs type looks for an
-// existing child with the given name, or returns ENOENT.
-func (n *OperationStubs) Lookup(ctx context.Context, name string, out *fuse.EntryOut) (*Inode, syscall.Errno) {
-	ch := n.inode().GetChild(name)
-	if ch == nil {
-		return nil, syscall.ENOENT
-	}
-
-	var a fuse.AttrOut
-	errno := ch.Operations().Getattr(ctx, &a)
-	out.Attr = a.Attr
-	return ch, errno
-}
-
-// Mkdir returns EROFS
-func (n *OperationStubs) Mkdir(ctx context.Context, name string, mode uint32, out *fuse.EntryOut) (*Inode, syscall.Errno) {
-	return nil, syscall.EROFS
-}
-
-// Mknod returns EROFS
-func (n *OperationStubs) Mknod(ctx context.Context, name string, mode uint32, dev uint32, out *fuse.EntryOut) (*Inode, syscall.Errno) {
-	return nil, syscall.EROFS
-}
-
-// Rmdir returns EROFS
-func (n *OperationStubs) Rmdir(ctx context.Context, name string) syscall.Errno {
-	return syscall.EROFS
-}
-
-// Unlink returns EROFS
-func (n *OperationStubs) Unlink(ctx context.Context, name string) syscall.Errno {
-	return syscall.EROFS
-}
-
-// The default OpenDir always succeeds
-func (n *OperationStubs) Opendir(ctx context.Context) syscall.Errno {
-	return OK
-}
-
-// The default ReadDir returns the list of children from the tree
-func (n *OperationStubs) Readdir(ctx context.Context) (DirStream, syscall.Errno) {
-	r := []fuse.DirEntry{}
-	for k, ch := range n.inode().Children() {
-		r = append(r, fuse.DirEntry{Mode: ch.Mode(),
-			Name: k,
-			Ino:  ch.NodeAttr().Ino})
-	}
-	return NewListDirStream(r), 0
-}
-
-// Rename returns EROFS
-func (n *OperationStubs) Rename(ctx context.Context, name string, newParent Operations, newName string, flags uint32) syscall.Errno {
-	return syscall.EROFS
-}
-
-// Read delegates to the FileHandle argument.
-func (n *OperationStubs) Read(ctx context.Context, f FileHandle, dest []byte, off int64) (fuse.ReadResult, syscall.Errno) {
-	if f != nil {
-		return f.Read(ctx, dest, off)
-	}
-	return nil, syscall.ENOTSUP
-}
-
-// Symlink returns EROFS
-func (n *OperationStubs) Symlink(ctx context.Context, target, name string, out *fuse.EntryOut) (node *Inode, errno syscall.Errno) {
-	return nil, syscall.EROFS
-}
-
-// Readlink return ENOTSUP
-func (n *OperationStubs) Readlink(ctx context.Context) ([]byte, syscall.Errno) {
-	return nil, syscall.ENOTSUP
-}
-
-// Fsync delegates to the FileHandle
-func (n *OperationStubs) Fsync(ctx context.Context, f FileHandle, flags uint32) syscall.Errno {
-	if f != nil {
-		return f.Fsync(ctx, flags)
-	}
-	return syscall.ENOTSUP
-}
-
-// Write delegates to the FileHandle
-func (n *OperationStubs) Write(ctx context.Context, f FileHandle, data []byte, off int64) (written uint32, errno syscall.Errno) {
-	if f != nil {
-		return f.Write(ctx, data, off)
-	}
-
-	return 0, syscall.EROFS
-}
-
-func (n *OperationStubs) CopyFileRange(ctx context.Context, fhIn FileHandle,
-	offIn uint64, out *Inode, fhOut FileHandle, offOut uint64,
-	len uint64, flags uint64) (uint32, syscall.Errno) {
-	return 0, syscall.EROFS
-}
-
-// Lseek is called for seeking to and beyond holes. By default, it
-// returns the input offset unchanged.
-func (n *OperationStubs) Lseek(ctx context.Context, f FileHandle, off uint64, whence uint32) (uint64, syscall.Errno) {
-	if f != nil {
-		return f.Lseek(ctx, off, whence)
-	}
-	if whence == _SEEK_DATA || whence == _SEEK_HOLE {
-		return off, OK
-	}
-
-	return 0, syscall.ENOTSUP
-}
-
-// Getlk delegates to the FileHandlef
-func (n *OperationStubs) Getlk(ctx context.Context, f FileHandle, owner uint64, lk *fuse.FileLock, flags uint32, out *fuse.FileLock) (errno syscall.Errno) {
-	if f != nil {
-		return f.Getlk(ctx, owner, lk, flags, out)
-	}
-
-	return syscall.ENOTSUP
-}
-
-// SetLk delegates to the FileHandle
-func (n *OperationStubs) Setlk(ctx context.Context, f FileHandle, owner uint64, lk *fuse.FileLock, flags uint32) (errno syscall.Errno) {
-	if f != nil {
-		return f.Setlk(ctx, owner, lk, flags)
-	}
-
-	return syscall.ENOTSUP
-}
-
-// SetLkw delegates to the FileHandle
-func (n *OperationStubs) Setlkw(ctx context.Context, f FileHandle, owner uint64, lk *fuse.FileLock, flags uint32) (errno syscall.Errno) {
-	if f != nil {
-		return f.Setlkw(ctx, owner, lk, flags)
-	}
-
-	return syscall.ENOTSUP
-}
-
-// Flush delegates to the FileHandle
-func (n *OperationStubs) Flush(ctx context.Context, f FileHandle) syscall.Errno {
-	if f != nil {
-		return f.Flush(ctx)
-	}
-
-	return syscall.ENOTSUP
-}
-
-// Release delegates to the FileHandle
-func (n *OperationStubs) Release(ctx context.Context, f FileHandle) syscall.Errno {
-	if f != nil {
-		return f.Release(ctx)
-	}
-	return OK
-}
-
-// Allocate delegates to the FileHandle
-func (n *OperationStubs) Allocate(ctx context.Context, f FileHandle, off uint64, size uint64, mode uint32) (errno syscall.Errno) {
-	if f != nil {
-		return f.Allocate(ctx, off, size, mode)
-	}
-
-	return syscall.ENOTSUP
-}
-
-// Fgetattr delegates to the FileHandle's if f is not nil, or else to the
-// Inode's GetAttr method.
-func (n *OperationStubs) Fgetattr(ctx context.Context, f FileHandle, out *fuse.AttrOut) syscall.Errno {
-	if f != nil {
-		f.Getattr(ctx, out)
-	}
-	return n.inode_.ops.Getattr(ctx, out)
-}
-
-// Open returns ENOTSUP
-func (n *OperationStubs) Open(ctx context.Context, flags uint32) (fh FileHandle, fuseFlags uint32, errno syscall.Errno) {
-	return nil, 0, syscall.ENOTSUP
-}
-
-// Create returns ENOTSUP
-func (n *OperationStubs) Create(ctx context.Context, name string, flags uint32, mode uint32) (node *Inode, fh FileHandle, fuseFlags uint32, errno syscall.Errno) {
-	return nil, nil, 0, syscall.EROFS
-}
-
-// Link returns ENOTSUP
-func (n *OperationStubs) Link(ctx context.Context, target Operations, name string, out *fuse.EntryOut) (node *Inode, errno syscall.Errno) {
-	return nil, syscall.EROFS
-}
-
-// The default GetXAttr returns ENOATTR
-func (n *OperationStubs) GetXAttr(ctx context.Context, attr string, dest []byte) (uint32, syscall.Errno) {
-	return 0, ENOATTR
-}
-
-// The default SetXAttr returns ENOATTR
-func (n *OperationStubs) SetXAttr(ctx context.Context, attr string, data []byte, flags uint32) syscall.Errno {
-	return syscall.EROFS
-}
-
-// The default RemoveXAttr returns ENOATTR
-func (n *OperationStubs) RemoveXAttr(ctx context.Context, attr string) syscall.Errno {
-	return ENOATTR
-}
-
-// The default RemoveXAttr returns an empty list
-func (n *OperationStubs) ListXAttr(ctx context.Context, dest []byte) (uint32, syscall.Errno) {
-	return 0, OK
-}
-
-// FileHandleStubs satisfies the FileHandle interface, and provides
-// stub methods that return ENOTSUP for all operations.
-type FileHandleStubs struct {
-}
-
-var _ = FileHandle((*FileHandleStubs)(nil))
-
-func (f *FileHandleStubs) Read(ctx context.Context, dest []byte, off int64) (fuse.ReadResult, syscall.Errno) {
-	return nil, syscall.ENOTSUP
-}
-
-func (f *FileHandleStubs) Write(ctx context.Context, data []byte, off int64) (written uint32, errno syscall.Errno) {
-	return 0, syscall.ENOTSUP
-}
-
-func (f *FileHandleStubs) Getlk(ctx context.Context, owner uint64, lk *fuse.FileLock, flags uint32, out *fuse.FileLock) (errno syscall.Errno) {
-	return syscall.ENOTSUP
-}
-
-func (f *FileHandleStubs) Setlk(ctx context.Context, owner uint64, lk *fuse.FileLock, flags uint32) (errno syscall.Errno) {
-	return syscall.ENOTSUP
-}
-
-func (f *FileHandleStubs) Setlkw(ctx context.Context, owner uint64, lk *fuse.FileLock, flags uint32) (errno syscall.Errno) {
-	return syscall.ENOTSUP
-}
-
-func (f *FileHandleStubs) Flush(ctx context.Context) syscall.Errno {
-	return syscall.ENOTSUP
-}
-
-func (f *FileHandleStubs) Release(ctx context.Context) syscall.Errno {
-	return syscall.ENOTSUP
-}
-
-func (f *FileHandleStubs) Getattr(ctx context.Context, out *fuse.AttrOut) syscall.Errno {
-	return syscall.ENOTSUP
-}
-
-func (f *FileHandleStubs) Setattr(ctx context.Context, in *fuse.SetAttrIn, out *fuse.AttrOut) syscall.Errno {
-	return syscall.ENOTSUP
-}
-
-func (f *FileHandleStubs) Allocate(ctx context.Context, off uint64, size uint64, mode uint32) (errno syscall.Errno) {
-	return syscall.ENOTSUP
-}
-
-func (f *FileHandleStubs) Fsync(ctx context.Context, flags uint32) (errno syscall.Errno) {
-	return syscall.ENOTSUP
-}
-
-func (f *FileHandleStubs) Lseek(ctx context.Context, off uint64, whence uint32) (uint64, syscall.Errno) {
-	return 0, syscall.ENOTSUP
-}

nodefs/directio_test.go

@@ -17,7 +17,7 @@ import (
 )
 
 type dioRoot struct {
-	OperationStubs
+	InodeEmbed
 }
 
 func (r *dioRoot) OnAdd(ctx context.Context) {
@@ -27,9 +27,11 @@ func (r *dioRoot) OnAdd(ctx context.Context) {
 // A file handle that pretends that every hole/data starts at
 // multiples of 1024
 type dioFH struct {
-	FileHandleStubs
 }
 
+var _ = (FileLseeker)((*dioFH)(nil))
+var _ = (FileReader)((*dioFH)(nil))
+
 func (f *dioFH) Lseek(ctx context.Context, off uint64, whence uint32) (uint64, syscall.Errno) {
 	next := (off + 1023) & (^uint64(1023))
 	return next, OK
@@ -42,9 +44,11 @@ func (fh *dioFH) Read(ctx context.Context, data []byte, off int64) (fuse.ReadRes
 
 // overrides Open so it can return a dioFH file handle
 type dioFile struct {
-	OperationStubs
+	InodeEmbed
 }
 
+var _ = (Opener)((*dioFile)(nil))
+
 func (f *dioFile) Open(ctx context.Context, flags uint32) (fh FileHandle, fuseFlags uint32, errno syscall.Errno) {
 	return &dioFH{}, fuse.FOPEN_DIRECT_IO, OK
 }

nodefs/files.go

@@ -24,6 +24,20 @@ type loopbackFile struct {
 	fd int
 }
 
+var _ = (FileHandle)((*loopbackFile)(nil))
+var _ = (FileReleaser)((*loopbackFile)(nil))
+var _ = (FileGetattrer)((*loopbackFile)(nil))
+var _ = (FileReader)((*loopbackFile)(nil))
+var _ = (FileWriter)((*loopbackFile)(nil))
+var _ = (FileGetlker)((*loopbackFile)(nil))
+var _ = (FileSetlker)((*loopbackFile)(nil))
+var _ = (FileSetlkwer)((*loopbackFile)(nil))
+var _ = (FileLseeker)((*loopbackFile)(nil))
+var _ = (FileFlusher)((*loopbackFile)(nil))
+var _ = (FileFsyncer)((*loopbackFile)(nil))
+var _ = (FileSetattrer)((*loopbackFile)(nil))
+var _ = (FileAllocater)((*loopbackFile)(nil))
+
 func (f *loopbackFile) Read(ctx context.Context, buf []byte, off int64) (res fuse.ReadResult, errno syscall.Errno) {
 	r := fuse.ReadResultFd(uintptr(f.fd), off, len(buf))
 	return r, OK

nodefs/inode.go

@@ -53,7 +53,7 @@ func (i *NodeAttr) Reserved() bool {
 type Inode struct {
 	nodeAttr NodeAttr
 
-	ops    Operations
+	ops    InodeLink
 	bridge *rawBridge
 
 	// Following data is mutable.
@@ -90,18 +90,6 @@ type Inode struct {
 	parents  map[parentData]struct{}
 }
 
-func (n *Inode) dirOps() DirOperations {
-	return n.ops.(DirOperations)
-}
-
-func (n *Inode) fileOps() FileOperations {
-	return n.ops.(FileOperations)
-}
-
-func (n *Inode) linkOps() SymlinkOperations {
-	return n.ops.(SymlinkOperations)
-}
-
 // NodeAttr returns the (Ino, Gen) tuple for this node.
 func (n *Inode) NodeAttr() NodeAttr {
 	return n.nodeAttr
@@ -214,7 +202,7 @@ func (n *Inode) Forgotten() bool {
 
 // Operations returns the object implementing the file system
 // operations.
-func (n *Inode) Operations() Operations {
+func (n *Inode) Operations() InodeLink {
 	return n.ops
 }
 
@@ -273,7 +261,7 @@ func (iparent *Inode) setEntry(name string, ichild *Inode) {
 
 // NewPersistentInode returns an Inode whose lifetime is not in
 // control of the kernel.
-func (n *Inode) NewPersistentInode(ctx context.Context, node Operations, id NodeAttr) *Inode {
+func (n *Inode) NewPersistentInode(ctx context.Context, node InodeLink, id NodeAttr) *Inode {
 	return n.newInode(ctx, node, id, true)
 }
 
@@ -284,16 +272,16 @@ func (n *Inode) ForgetPersistent() {
 	n.removeRef(0, true)
 }
 
-// NewInode returns an inode for the given Operations. The mode should
+// NewInode returns an inode for the given InodeLink. The mode should
 // be standard mode argument (eg. S_IFDIR). The inode number in id.Ino
 // argument is used to implement hard-links.  If it is given, and
 // another node with the same ID is known, that will node will be
 // returned, and the passed-in `node` is ignored.
-func (n *Inode) NewInode(ctx context.Context, ops Operations, id NodeAttr) *Inode {
+func (n *Inode) NewInode(ctx context.Context, ops InodeLink, id NodeAttr) *Inode {
 	return n.newInode(ctx, ops, id, false)
 }
 
-func (n *Inode) newInode(ctx context.Context, ops Operations, id NodeAttr, persistent bool) *Inode {
+func (n *Inode) newInode(ctx context.Context, ops InodeLink, id NodeAttr, persistent bool) *Inode {
 	return n.bridge.newInode(ctx, ops, id, persistent)
 }
 

nodefs/interrupt_test.go

@@ -17,14 +17,11 @@ import (
 )
 
 type interruptRoot struct {
-	OperationStubs
+	InodeEmbed
 	child interruptOps
 }
 
-type interruptOps struct {
-	OperationStubs
-	interrupted bool
-}
+var _ = (Lookuper)((*interruptRoot)(nil))
 
 func (r *interruptRoot) Lookup(ctx context.Context, name string, out *fuse.EntryOut) (*Inode, syscall.Errno) {
 	if name != "file" {
@@ -37,6 +34,13 @@ func (r *interruptRoot) Lookup(ctx context.Context, name string, out *fuse.Entry
 	return ch, OK
 }
 
+type interruptOps struct {
+	InodeEmbed
+	interrupted bool
+}
+
+var _ = (Opener)((*interruptOps)(nil))
+
 func (o *interruptOps) Open(ctx context.Context, flags uint32) (FileHandle, uint32, syscall.Errno) {
 	select {
 	case <-time.After(100 * time.Millisecond):

nodefs/loopback.go

@@ -6,7 +6,6 @@ package nodefs
 
 import (
 	"context"
-	"log"
 	"os"
 	"path/filepath"
 	"syscall"
@@ -21,6 +20,27 @@ type loopbackRoot struct {
 	rootDev  uint64
 }
 
+var _ = (Statfser)((*loopbackNode)(nil))
+var _ = (Getattrer)((*loopbackNode)(nil))
+var _ = (Getxattrer)((*loopbackNode)(nil))
+var _ = (Setxattrer)((*loopbackNode)(nil))
+var _ = (Removexattrer)((*loopbackNode)(nil))
+var _ = (Listxattrer)((*loopbackNode)(nil))
+var _ = (Readlinker)((*loopbackNode)(nil))
+var _ = (Opener)((*loopbackNode)(nil))
+var _ = (CopyFileRanger)((*loopbackNode)(nil))
+var _ = (Lookuper)((*loopbackNode)(nil))
+var _ = (Opendirer)((*loopbackNode)(nil))
+var _ = (Readdirer)((*loopbackNode)(nil))
+var _ = (Mkdirer)((*loopbackNode)(nil))
+var _ = (Mknoder)((*loopbackNode)(nil))
+var _ = (Linker)((*loopbackNode)(nil))
+var _ = (Symlinker)((*loopbackNode)(nil))
+var _ = (Creater)((*loopbackNode)(nil))
+var _ = (Unlinker)((*loopbackNode)(nil))
+var _ = (Rmdirer)((*loopbackNode)(nil))
+var _ = (Renamer)((*loopbackNode)(nil))
+
 func (n *loopbackNode) Statfs(ctx context.Context, out *fuse.StatfsOut) syscall.Errno {
 	s := syscall.Statfs_t{}
 	err := syscall.Statfs(n.path(), &s)
@@ -32,7 +52,6 @@ func (n *loopbackNode) Statfs(ctx context.Context, out *fuse.StatfsOut) syscall.
 }
 
 func (n *loopbackRoot) Getattr(ctx context.Context, out *fuse.AttrOut) syscall.Errno {
-	log.Println("getattr")
 	st := syscall.Stat_t{}
 	err := syscall.Stat(n.rootPath, &st)
 	if err != nil {
@@ -43,7 +62,7 @@ func (n *loopbackRoot) Getattr(ctx context.Context, out *fuse.AttrOut) syscall.E
 }
 
 type loopbackNode struct {
-	OperationStubs
+	InodeEmbed
 }
 
 func (n *loopbackNode) root() *loopbackRoot {
@@ -122,14 +141,14 @@ func (n *loopbackNode) Unlink(ctx context.Context, name string) syscall.Errno {
 	return ToErrno(err)
 }
 
-func toLoopbackNode(op Operations) *loopbackNode {
+func toLoopbackNode(op InodeLink) *loopbackNode {
 	if r, ok := op.(*loopbackRoot); ok {
 		return &r.loopbackNode
 	}
 	return op.(*loopbackNode)
 }
 
-func (n *loopbackNode) Rename(ctx context.Context, name string, newParent Operations, newName string, flags uint32) syscall.Errno {
+func (n *loopbackNode) Rename(ctx context.Context, name string, newParent InodeLink, newName string, flags uint32) syscall.Errno {
 	newParentLoopback := toLoopbackNode(newParent)
 	if flags&RENAME_EXCHANGE != 0 {
 		return n.renameExchange(name, newParentLoopback, newName)
@@ -199,7 +218,7 @@ func (n *loopbackNode) Symlink(ctx context.Context, target, name string, out *fu
 	return ch, 0
 }
 
-func (n *loopbackNode) Link(ctx context.Context, target Operations, name string, out *fuse.EntryOut) (*Inode, syscall.Errno) {
+func (n *loopbackNode) Link(ctx context.Context, target InodeLink, name string, out *fuse.EntryOut) (*Inode, syscall.Errno) {
 
 	p := filepath.Join(n.path(), name)
 	targetNode := toLoopbackNode(target)
@@ -258,11 +277,7 @@ func (n *loopbackNode) Readdir(ctx context.Context) (DirStream, syscall.Errno) {
 	return NewLoopbackDirStream(n.path())
 }
 
-func (n *loopbackNode) Fgetattr(ctx context.Context, f FileHandle, out *fuse.AttrOut) syscall.Errno {
-	if f != nil {
-		return f.Getattr(ctx, out)
-	}
-
+func (n *loopbackNode) Getattr(ctx context.Context, out *fuse.AttrOut) syscall.Errno {
 	p := n.path()
 
 	var err error = nil
@@ -277,7 +292,7 @@ func (n *loopbackNode) Fgetattr(ctx context.Context, f FileHandle, out *fuse.Att
 
 // NewLoopback returns a root node for a loopback file system whose
 // root is at the given root.
-func NewLoopbackRoot(root string) (DirOperations, error) {
+func NewLoopbackRoot(root string) (InodeLink, error) {
 	var st syscall.Stat_t
 	err := syscall.Stat(root, &st)
 	if err != nil {

nodefs/mount.go

@@ -14,7 +14,7 @@ import (
 // requests. This is a convenience wrapper around NewNodeFS and
 // fuse.NewServer.  If nil is given as options, default settings are
 // applied, which are 1 second entry and attribute timeout.
-func Mount(dir string, root DirOperations, options *Options) (*fuse.Server, error) {
+func Mount(dir string, root InodeLink, options *Options) (*fuse.Server, error) {
 	if options == nil {
 		oneSec := time.Second
 		options = &Options{

nodefs/simple_test.go

@@ -28,7 +28,7 @@ type testCase struct {
 	origDir string
 	mntDir  string
 
-	loopback DirOperations
+	loopback InodeLink
 	rawFS    fuse.RawFileSystem
 	server   *fuse.Server
 }

nodefs/zip_test.go

@@ -106,14 +106,15 @@ func TestZipFS(t *testing.T) {
 
 // zipFile is a file read from a zip archive.
 type zipFile struct {
-	OperationStubs
+	InodeEmbed
 	file *zip.File
 
 	mu   sync.Mutex
 	data []byte
 }
 
-var _ = (FileOperations)((*zipFile)(nil))
+var _ = (Opener)((*zipFile)(nil))
+var _ = (Getattrer)((*zipFile)(nil))
 
 // Getattr sets the minimum, which is the size. A more full-featured
 // FS would also set timestamps and permissions.
@@ -157,11 +158,13 @@ func (zf *zipFile) Read(ctx context.Context, f FileHandle, dest []byte, off int6
 // zipRoot is the root of the Zip filesystem. Its only functionality
 // is populating the filesystem.
 type zipRoot struct {
-	OperationStubs
+	InodeEmbed
 
 	r *zip.Reader
 }
 
+var _ = (OnAdder)((*zipRoot)(nil))
+
 func (zr *zipRoot) OnAdd(ctx context.Context) {
 	// OnAdd is called once we are attached to an Inode. We can
 	// then construct a tree.  We construct the entire tree, and
@@ -177,7 +180,7 @@ func (zr *zipRoot) OnAdd(ctx context.Context) {
 			}
 			ch := p.GetChild(component)
 			if ch == nil {
-				ch = p.NewPersistentInode(ctx, &OperationStubs{},
+				ch = p.NewPersistentInode(ctx, &InodeEmbed{},
 					NodeAttr{Mode: fuse.S_IFDIR})
 				p.AddChild(component, ch, true)
 			}