Some work on getting cross-version file operations working

dir.go

@@ -81,29 +81,29 @@ func (vd *verDir) createDir(name string) (*verDir, error) {
 	node := newVerNode(childPath, vd.node.ver, nil, NodeFlagDir|NodeFlagVer)
 	dir := newVerDir(node, vd)
 	vd.dirs[name] = dir
-
 	node.ver.meta.createNode(node.path)
+
 	return dir, nil
 }
 
-func (vd *verDir) createFile(name string, flags int) (*verFile, error) {
+func (vd *verDir) createFile(name string, flags fuse.OpenFlags) (*verFile, *verFileHandle, error) {
 	if err := vd.version(); err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 
 	childPath := path.Join(vd.node.path, name)
-	handle, err := os.OpenFile(vd.node.ver.rebasePath(childPath), flags, 0644)
-	if err != nil {
-		return nil, err
-	}
-
 	node := newVerNode(childPath, vd.node.ver, nil, NodeFlagVer)
 	file := newVerFile(node, vd)
-	file.handle = handle
-	vd.files[name] = file
 
+	handle, err := file.open(flags)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	vd.files[name] = file
 	node.ver.meta.createNode(node.path)
-	return file, nil
+
+	return file, handle, nil
 }
 
 // Node
@@ -137,9 +137,11 @@ func (vd *verDir) Create(ctx context.Context, req *fuse.CreateRequest, resp *fus
 		}
 	} else if req.Mode.IsRegular() {
 		var file *verFile
-		if file, err = vd.createFile(req.Name, int(req.Flags)); err == nil {
+		var vfh *verFileHandle
+		if file, vfh, err = vd.createFile(req.Name, req.Flags); err == nil {
 			node = file
-			handle = file
+			handle = handle
+			resp.Handle = vfh.id
 		}
 	} else {
 		err = errors.New("unsupported filetype")

file.go

@@ -23,7 +23,6 @@
 package main
 
 import (
-	"errors"
 	"os"
 
 	"bazil.org/fuse"
@@ -39,11 +38,11 @@ type verFile struct {
 	node    *verNode
 	inode   uint64
 	parent  *verDir
-	handle *os.File
+	handles map[fuse.HandleID]*verFileHandle
 }
 
 func newVerFile(node *verNode, parent *verDir) *verFile {
-	return &verFile{node, allocInode(), parent, nil}
+	return &verFile{node, allocInode(), parent, make(map[fuse.HandleID]*verFileHandle)}
 }
 
 func (vf *verFile) version() error {
@@ -63,6 +62,30 @@ func (vf *verFile) version() error {
 	return nil
 }
 
+func (vf *verFile) open(flags fuse.OpenFlags) (*verFileHandle, error) {
+	if !flags.IsReadOnly() {
+		if err := vf.version(); err != nil {
+			return nil, err
+		}
+	}
+
+	path := vf.node.rebasedPath()
+	handle, err := os.OpenFile(path, int(flags), 0644)
+	if err != nil {
+		return nil, err
+	}
+
+	id := fuse.HandleID(allocHandleId())
+	verHandle := &verFileHandle{vf, path, handle, id}
+	vf.handles[id] = verHandle
+
+	return verHandle, nil
+}
+
+func (vf *verFile) release(handle fuse.HandleID) {
+	delete(vf.handles, handle)
+}
+
 // Node
 func (vf *verFile) Attr(ctx context.Context, attr *fuse.Attr) error {
 	vf.node.attr(attr)
@@ -82,54 +105,41 @@ func (vf *verFile) Setattr(ctx context.Context, req *fuse.SetattrRequest, resp *
 
 // NodeOpener
 func (vf *verFile) Open(ctx context.Context, req *fuse.OpenRequest, resp *fuse.OpenResponse) (fs.Handle, error) {
-	if vf.handle != nil {
+	handle, err := vf.open(req.Flags)
-		return nil, errors.New("attempted to open already opened file")
-	}
-
-	if !req.Flags.IsReadOnly() {
-		if err := vf.version(); err != nil {
-			return nil, err
-		}
-	}
-
-	handle, err := os.OpenFile(vf.node.rebasedPath(), int(req.Flags), 0644)
 	if err != nil {
 		return nil, err
 	}
 
-	vf.handle = handle
+	resp.Handle = handle.id
-	return vf, nil
+	return handle, nil
-}
-
-// HandleReleaser
-func (vf *verFile) Release(ctx context.Context, req *fuse.ReleaseRequest) error {
-	if vf.handle == nil {
-		return errors.New("attempted to release unopened file")
-	}
-
-	vf.handle.Close()
-	vf.handle = nil
-
-	return nil
 }
 
 // NodeFsyncer
 func (vf *verFile) Fsync(ctx context.Context, req *fuse.FsyncRequest) error {
-	if vf.handle == nil {
+	for _, vfh := range vf.handles {
-		return errors.New("attempted to sync unopened file")
+		if err := vfh.handle.Sync(); err != nil {
+			return err
+		}
 	}
 
-	return vf.handle.Sync()
+	return nil
+}
+
+//
+// verFileHandle
+//
+
+type verFileHandle struct {
+	node   *verFile
+	path   string
+	handle *os.File
+	id     fuse.HandleID
 }
 
 // HandleReader
-func (vf *verFile) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
+func (vfh *verFileHandle) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
-	if vf.handle == nil {
-		return errors.New("attempted to read from unopened file")
-	}
-
 	resp.Data = make([]byte, req.Size)
-	if _, err := vf.handle.ReadAt(resp.Data, req.Offset); err != nil {
+	if _, err := vfh.handle.ReadAt(resp.Data, req.Offset); err != nil {
 		return err
 	}
 
@@ -137,18 +147,14 @@ func (vf *verFile) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.R
 }
 
 // HandleReadAller
-func (vf *verFile) ReadAll(ctx context.Context) ([]byte, error) {
+func (vfh *verFileHandle) ReadAll(ctx context.Context) ([]byte, error) {
-	if vf.handle == nil {
+	info, err := os.Stat(vfh.path)
-		return nil, errors.New("attempted to read from unopened file")
-	}
-
-	info, err := os.Stat(vf.node.rebasedPath())
 	if err != nil {
 		return nil, err
 	}
 
 	data := make([]byte, info.Size())
-	if _, err := vf.handle.Read(data); err != nil {
+	if _, err := vfh.handle.Read(data); err != nil {
 		return nil, err
 	}
 
@@ -156,12 +162,8 @@ func (vf *verFile) ReadAll(ctx context.Context) ([]byte, error) {
 }
 
 // HandleWriter
-func (vf *verFile) Write(ctx context.Context, req *fuse.WriteRequest, resp *fuse.WriteResponse) error {
+func (vfh *verFileHandle) Write(ctx context.Context, req *fuse.WriteRequest, resp *fuse.WriteResponse) error {
-	if vf.handle == nil {
+	size, err := vfh.handle.WriteAt(req.Data, req.Offset)
-		return errors.New("attempted to write to unopened file")
-	}
-
-	size, err := vf.handle.WriteAt(req.Data, req.Offset)
 	if err != nil {
 		return err
 	}
@@ -169,3 +171,12 @@ func (vf *verFile) Write(ctx context.Context, req *fuse.WriteRequest, resp *fuse
 	resp.Size = size
 	return nil
 }
+
+// HandleReleaser
+func (vfh *verFileHandle) Release(ctx context.Context, req *fuse.ReleaseRequest) error {
+	vfh.handle.Close()
+	vfh.handle = nil
+
+	vfh.node.release(req.Handle)
+	return nil
+}

util.go

@@ -32,14 +32,20 @@ import (
 	"strconv"
 	"sync/atomic"
 	"time"
+
+	"bazil.org/fuse"
 )
 
-var inodeCnt uint64
+var inodeCnt, handleCnt uint64
 
 func allocInode() uint64 {
 	return atomic.AddUint64(&inodeCnt, 1)
 }
 
+func allocHandleId() fuse.HandleID {
+	return fuse.HandleID(atomic.AddUint64(&handleCnt, 1))
+}
+
 func copyFile(src, dst string) (int64, error) {
 	srcFile, err := os.Open(src)
 	if err != nil {