vfs: add --vfs-writeback option to delay writes back to cloud storage

This is enabled by default and can be disabled with --vfs-writeback 0

vfs/dir_handle_test.go

@@ -12,9 +12,8 @@ import (
 )
 
 func TestDirHandleMethods(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, dir, _, cleanup := dirCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	_, dir, _ := dirCreate(t, r)
 
 	h, err := dir.Open(os.O_RDONLY)
 	require.NoError(t, err)
@@ -40,9 +39,8 @@ func TestDirHandleMethods(t *testing.T) {
 }
 
 func TestDirHandleReaddir(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, cleanup := newTestVFS(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs := New(r.Fremote, nil)
 
 	file1 := r.WriteObject(context.Background(), "dir/file1", "file1 contents", t1)
 	file2 := r.WriteObject(context.Background(), "dir/file2", "file2- contents", t2)
@@ -96,9 +94,8 @@ func TestDirHandleReaddir(t *testing.T) {
 }
 
 func TestDirHandleReaddirnames(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, dir, _, cleanup := dirCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	_, dir, _ := dirCreate(t, r)
 
 	fh, err := dir.Open(os.O_RDONLY)
 	require.NoError(t, err)

vfs/dir_test.go

@@ -14,8 +14,8 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func dirCreate(t *testing.T, r *fstest.Run) (*VFS, *Dir, fstest.Item) {
+func dirCreate(t *testing.T) (r *fstest.Run, vfs *VFS, dir *Dir, item fstest.Item, cleanup func()) {
-	vfs := New(r.Fremote, nil)
+	r, vfs, cleanup = newTestVFS(t)
 
 	file1 := r.WriteObject(context.Background(), "dir/file1", "file1 contents", t1)
 	fstest.CheckItems(t, r.Fremote, file1)
@@ -24,13 +24,12 @@ func dirCreate(t *testing.T, r *fstest.Run) (*VFS, *Dir, fstest.Item) {
 	require.NoError(t, err)
 	require.True(t, node.IsDir())
 
-	return vfs, node.(*Dir), file1
+	return r, vfs, node.(*Dir), file1, cleanup
 }
 
 func TestDirMethods(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, vfs, dir, _, cleanup := dirCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, dir, _ := dirCreate(t, r)
 
 	// String
 	assert.Equal(t, "dir/", dir.String())
@@ -81,9 +80,8 @@ func TestDirMethods(t *testing.T) {
 }
 
 func TestDirForgetAll(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, vfs, dir, file1, cleanup := dirCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, dir, file1 := dirCreate(t, r)
 
 	// Make sure / and dir are in cache
 	_, err := vfs.Stat(file1.Path)
@@ -110,9 +108,8 @@ func TestDirForgetAll(t *testing.T) {
 }
 
 func TestDirForgetPath(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, vfs, dir, file1, cleanup := dirCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, dir, file1 := dirCreate(t, r)
 
 	// Make sure / and dir are in cache
 	_, err := vfs.Stat(file1.Path)
@@ -143,9 +140,8 @@ func TestDirForgetPath(t *testing.T) {
 }
 
 func TestDirWalk(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, _, file1, cleanup := dirCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, _, file1 := dirCreate(t, r)
 
 	file2 := r.WriteObject(context.Background(), "fil/a/b/c", "super long file", t1)
 	fstest.CheckItems(t, r.Fremote, file1, file2)
@@ -213,9 +209,8 @@ func TestDirWalk(t *testing.T) {
 }
 
 func TestDirSetModTime(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, vfs, dir, _, cleanup := dirCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, dir, _ := dirCreate(t, r)
 
 	err := dir.SetModTime(t1)
 	require.NoError(t, err)
@@ -231,9 +226,8 @@ func TestDirSetModTime(t *testing.T) {
 }
 
 func TestDirStat(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, dir, _, cleanup := dirCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	_, dir, _ := dirCreate(t, r)
 
 	node, err := dir.Stat("file1")
 	require.NoError(t, err)
@@ -258,9 +252,8 @@ func checkListing(t *testing.T, dir *Dir, want []string) {
 }
 
 func TestDirReadDirAll(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, cleanup := newTestVFS(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs := New(r.Fremote, nil)
 
 	file1 := r.WriteObject(context.Background(), "dir/file1", "file1 contents", t1)
 	file2 := r.WriteObject(context.Background(), "dir/file2", "file2- contents", t2)
@@ -287,9 +280,8 @@ func TestDirReadDirAll(t *testing.T) {
 }
 
 func TestDirOpen(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, dir, _, cleanup := dirCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	_, dir, _ := dirCreate(t, r)
 
 	fd, err := dir.Open(os.O_RDONLY)
 	require.NoError(t, err)
@@ -302,9 +294,8 @@ func TestDirOpen(t *testing.T) {
 }
 
 func TestDirCreate(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, vfs, dir, _, cleanup := dirCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, dir, _ := dirCreate(t, r)
 
 	file, err := dir.Create("potato", os.O_WRONLY|os.O_CREATE)
 	require.NoError(t, err)
@@ -336,9 +327,8 @@ func TestDirCreate(t *testing.T) {
 }
 
 func TestDirMkdir(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, dir, file1, cleanup := dirCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, dir, file1 := dirCreate(t, r)
 
 	_, err := dir.Mkdir("file1")
 	assert.Error(t, err)
@@ -359,9 +349,8 @@ func TestDirMkdir(t *testing.T) {
 }
 
 func TestDirMkdirSub(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, dir, file1, cleanup := dirCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, dir, file1 := dirCreate(t, r)
 
 	_, err := dir.Mkdir("file1")
 	assert.Error(t, err)
@@ -386,9 +375,8 @@ func TestDirMkdirSub(t *testing.T) {
 }
 
 func TestDirRemove(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, dir, _, cleanup := dirCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, dir, _ := dirCreate(t, r)
 
 	// check directory is there
 	node, err := vfs.Stat("dir")
@@ -427,9 +415,8 @@ func TestDirRemove(t *testing.T) {
 }
 
 func TestDirRemoveAll(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, dir, _, cleanup := dirCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, dir, _ := dirCreate(t, r)
 
 	// Remove the directory and contents
 	err := dir.RemoveAll()
@@ -450,9 +437,8 @@ func TestDirRemoveAll(t *testing.T) {
 }
 
 func TestDirRemoveName(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, dir, _, cleanup := dirCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, dir, _ := dirCreate(t, r)
 
 	err := dir.RemoveName("file1")
 	require.NoError(t, err)
@@ -471,15 +457,14 @@ func TestDirRemoveName(t *testing.T) {
 }
 
 func TestDirRename(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, dir, file1, cleanup := dirCreate(t)
-	defer r.Finalise()
+	defer cleanup()
 
 	features := r.Fremote.Features()
 	if features.DirMove == nil && features.Move == nil && features.Copy == nil {
-		return // skip as can't rename directories
+		t.Skip("can't rename directories")
 	}
 
-	vfs, dir, file1 := dirCreate(t, r)
 	file3 := r.WriteObject(context.Background(), "dir/file3", "file3 contents!", t1)
 	fstest.CheckListingWithPrecision(t, r.Fremote, []fstest.Item{file1, file3}, []string{"dir"}, r.Fremote.Precision())
 

vfs/file.go

@@ -325,6 +325,18 @@ func (f *File) Size() int64 {
 	f.mu.RLock()
 	defer f.mu.RUnlock()
 
+	// Read the size from a dirty item if it exists
+	if f.d.vfs.Opt.CacheMode >= vfscommon.CacheModeMinimal {
+		if item := f.d.vfs.cache.DirtyItem(f._path()); item != nil {
+			size, err := item.GetSize()
+			if err != nil {
+				fs.Errorf(f._path(), "Size: Item GetSize failed: %v", err)
+			} else {
+				return size
+			}
+		}
+	}
+
 	// if o is nil it isn't valid yet or there are writers, so return the size so far
 	if f._writingInProgress() {
 		return atomic.LoadInt64(&f.size)

vfs/file_test.go

@@ -16,10 +16,11 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func fileCreate(t *testing.T, r *fstest.Run, mode vfscommon.CacheMode) (*VFS, *File, fstest.Item) {
+func fileCreate(t *testing.T, mode vfscommon.CacheMode) (r *fstest.Run, vfs *VFS, fh *File, item fstest.Item, cleanup func()) {
 	opt := vfscommon.DefaultOpt
 	opt.CacheMode = mode
-	vfs := New(r.Fremote, &opt)
+	opt.WriteBack = writeBackDelay
+	r, vfs, cleanup = newTestVFSOpt(t, &opt)
 
 	file1 := r.WriteObject(context.Background(), "dir/file1", "file1 contents", t1)
 	fstest.CheckItems(t, r.Fremote, file1)
@@ -28,13 +29,12 @@ func fileCreate(t *testing.T, r *fstest.Run, mode vfscommon.CacheMode) (*VFS, *F
 	require.NoError(t, err)
 	require.True(t, node.Mode().IsRegular())
 
-	return vfs, node.(*File), file1
+	return r, vfs, node.(*File), file1, cleanup
 }
 
 func TestFileMethods(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, file, _, cleanup := fileCreate(t, vfscommon.CacheModeOff)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, file, _ := fileCreate(t, r, vfscommon.CacheModeOff)
 
 	// String
 	assert.Equal(t, "dir/file1", file.String())
@@ -88,12 +88,11 @@ func TestFileMethods(t *testing.T) {
 }
 
 func TestFileSetModTime(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, file, file1, cleanup := fileCreate(t, vfscommon.CacheModeOff)
+	defer cleanup()
 	if !canSetModTime(t, r) {
-		return
+		t.Skip("can't set mod time")
 	}
-	defer r.Finalise()
-	vfs, file, file1 := fileCreate(t, r, vfscommon.CacheModeOff)
 
 	err := file.SetModTime(t2)
 	require.NoError(t, err)
@@ -118,9 +117,8 @@ func fileCheckContents(t *testing.T, file *File) {
 }
 
 func TestFileOpenRead(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, file, _, cleanup := fileCreate(t, vfscommon.CacheModeOff)
-	defer r.Finalise()
+	defer cleanup()
-	_, file, _ := fileCreate(t, r, vfscommon.CacheModeOff)
 
 	fileCheckContents(t, file)
 }
@@ -146,6 +144,7 @@ func TestFileOpenReadUnknownSize(t *testing.T) {
 
 	// create a VFS from that mockfs
 	vfs := New(f, nil)
+	defer cleanupVFS(t, vfs)
 
 	// find the file
 	node, err := vfs.Stat(remote)
@@ -171,9 +170,8 @@ func TestFileOpenReadUnknownSize(t *testing.T) {
 }
 
 func TestFileOpenWrite(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, vfs, file, _, cleanup := fileCreate(t, vfscommon.CacheModeOff)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, file, _ := fileCreate(t, r, vfscommon.CacheModeOff)
 
 	fd, err := file.openWrite(os.O_WRONLY | os.O_TRUNC)
 	require.NoError(t, err)
@@ -192,9 +190,8 @@ func TestFileOpenWrite(t *testing.T) {
 }
 
 func TestFileRemove(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, file, _, cleanup := fileCreate(t, vfscommon.CacheModeOff)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, file, _ := fileCreate(t, r, vfscommon.CacheModeOff)
 
 	err := file.Remove()
 	require.NoError(t, err)
@@ -207,9 +204,8 @@ func TestFileRemove(t *testing.T) {
 }
 
 func TestFileRemoveAll(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, file, _, cleanup := fileCreate(t, vfscommon.CacheModeOff)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, file, _ := fileCreate(t, r, vfscommon.CacheModeOff)
 
 	err := file.RemoveAll()
 	require.NoError(t, err)
@@ -222,9 +218,8 @@ func TestFileRemoveAll(t *testing.T) {
 }
 
 func TestFileOpen(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, file, _, cleanup := fileCreate(t, vfscommon.CacheModeOff)
-	defer r.Finalise()
+	defer cleanup()
-	_, file, _ := fileCreate(t, r, vfscommon.CacheModeOff)
 
 	fd, err := file.Open(os.O_RDONLY)
 	require.NoError(t, err)
@@ -242,15 +237,15 @@ func TestFileOpen(t *testing.T) {
 	assert.NoError(t, err)
 	_, ok = fd.(*WriteFileHandle)
 	assert.True(t, ok)
+	require.NoError(t, fd.Close())
 
 	_, err = file.Open(3)
 	assert.Equal(t, EPERM, err)
 }
 
 func testFileRename(t *testing.T, mode vfscommon.CacheMode) {
-	r := fstest.NewRun(t)
+	r, vfs, file, item, cleanup := fileCreate(t, mode)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, file, item := fileCreate(t, r, mode)
 
 	if !operations.CanServerSideMove(r.Fremote) {
 		t.Skip("skip as can't rename files")
@@ -326,6 +321,7 @@ func testFileRename(t *testing.T, mode vfscommon.CacheMode) {
 
 	// Check file has now been renamed on the remote
 	item.Path = "newLeaf"
+	vfs.WaitForWriters(waitForWritersDelay)
 	fstest.CheckListingWithPrecision(t, r.Fremote, []fstest.Item{newItem}, nil, fs.ModTimeNotSupported)
 }
 

vfs/read_test.go

@@ -12,8 +12,8 @@ import (
 )
 
 // Open a file for write
-func readHandleCreate(t *testing.T, r *fstest.Run) (*VFS, *ReadFileHandle) {
+func readHandleCreate(t *testing.T) (r *fstest.Run, vfs *VFS, fh *ReadFileHandle, cleanup func()) {
-	vfs := New(r.Fremote, nil)
+	r, vfs, cleanup = newTestVFS(t)
 
 	file1 := r.WriteObject(context.Background(), "dir/file1", "0123456789abcdef", t1)
 	fstest.CheckItems(t, r.Fremote, file1)
@@ -23,7 +23,7 @@ func readHandleCreate(t *testing.T, r *fstest.Run) (*VFS, *ReadFileHandle) {
 	fh, ok := h.(*ReadFileHandle)
 	require.True(t, ok)
 
-	return vfs, fh
+	return r, vfs, fh, cleanup
 }
 
 // read data from the string
@@ -37,9 +37,8 @@ func readString(t *testing.T, fh *ReadFileHandle, n int) string {
 }
 
 func TestReadFileHandleMethods(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, fh, cleanup := readHandleCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	_, fh := readHandleCreate(t, r)
 
 	// String
 	assert.Equal(t, "dir/file1 (r)", fh.String())
@@ -81,9 +80,8 @@ func TestReadFileHandleMethods(t *testing.T) {
 }
 
 func TestReadFileHandleSeek(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, fh, cleanup := readHandleCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	_, fh := readHandleCreate(t, r)
 
 	assert.Equal(t, "0", readString(t, fh, 1))
 
@@ -125,9 +123,8 @@ func TestReadFileHandleSeek(t *testing.T) {
 }
 
 func TestReadFileHandleReadAt(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, fh, cleanup := readHandleCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	_, fh := readHandleCreate(t, r)
 
 	// read from start
 	buf := make([]byte, 1)
@@ -182,9 +179,8 @@ func TestReadFileHandleReadAt(t *testing.T) {
 }
 
 func TestReadFileHandleFlush(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, fh, cleanup := readHandleCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	_, fh := readHandleCreate(t, r)
 
 	// Check Flush does nothing if read not called
 	err := fh.Flush()
@@ -212,9 +208,8 @@ func TestReadFileHandleFlush(t *testing.T) {
 }
 
 func TestReadFileHandleRelease(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, fh, cleanup := readHandleCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	_, fh := readHandleCreate(t, r)
 
 	// Check Release does nothing if file not read from
 	err := fh.Release()

vfs/read_write.go

@@ -36,7 +36,7 @@ func newRWFileHandle(d *Dir, f *File, flags int) (fh *RWFileHandle, err error) {
 	// get an item to represent this from the cache
 	item := d.vfs.cache.Item(f.Path())
 
-	exists := f.exists() // || item.Exists()
+	exists := f.exists() || item.Exists()
 
 	// if O_CREATE and O_EXCL are set and if path already exists, then return EEXIST
 	if flags&(os.O_CREATE|os.O_EXCL) == os.O_CREATE|os.O_EXCL && exists {
@@ -51,7 +51,7 @@ func newRWFileHandle(d *Dir, f *File, flags int) (fh *RWFileHandle, err error) {
 	}
 
 	// truncate immediately if O_TRUNC is set or O_CREATE is set and file doesn't exist
-	if !fh.readOnly() && (fh.flags&os.O_TRUNC != 0 || (fh.flags&os.O_CREATE != 0 && !(exists || item.Exists()))) {
+	if !fh.readOnly() && (fh.flags&os.O_TRUNC != 0 || (fh.flags&os.O_CREATE != 0 && !exists)) {
 		err = fh.Truncate(0)
 		if err != nil {
 			return nil, errors.Wrap(err, "cache open with O_TRUNC: failed to truncate")

vfs/read_write_test.go

@@ -29,17 +29,12 @@ var (
 	_ Handle      = (*RWFileHandle)(nil)
 )
 
-func cleanup(t *testing.T, r *fstest.Run, vfs *VFS) {
-	assert.NoError(t, vfs.CleanUp())
-	vfs.Shutdown()
-	r.Finalise()
-}
-
 // Create a file and open it with the flags passed in
-func rwHandleCreateFlags(t *testing.T, r *fstest.Run, create bool, filename string, flags int) (*VFS, *RWFileHandle) {
+func rwHandleCreateFlags(t *testing.T, create bool, filename string, flags int) (r *fstest.Run, vfs *VFS, fh *RWFileHandle, cleanup func()) {
 	opt := vfscommon.DefaultOpt
 	opt.CacheMode = vfscommon.CacheModeFull
-	vfs := New(r.Fremote, &opt)
+	opt.WriteBack = writeBackDelay
+	r, vfs, cleanup = newTestVFSOpt(t, &opt)
 
 	if create {
 		file1 := r.WriteObject(context.Background(), filename, "0123456789abcdef", t1)
@@ -51,17 +46,17 @@ func rwHandleCreateFlags(t *testing.T, r *fstest.Run, create bool, filename stri
 	fh, ok := h.(*RWFileHandle)
 	require.True(t, ok)
 
-	return vfs, fh
+	return r, vfs, fh, cleanup
 }
 
 // Open a file for read
-func rwHandleCreateReadOnly(t *testing.T, r *fstest.Run) (*VFS, *RWFileHandle) {
+func rwHandleCreateReadOnly(t *testing.T) (r *fstest.Run, vfs *VFS, fh *RWFileHandle, cleanup func()) {
-	return rwHandleCreateFlags(t, r, true, "dir/file1", os.O_RDONLY)
+	return rwHandleCreateFlags(t, true, "dir/file1", os.O_RDONLY)
 }
 
 // Open a file for write
-func rwHandleCreateWriteOnly(t *testing.T, r *fstest.Run) (*VFS, *RWFileHandle) {
+func rwHandleCreateWriteOnly(t *testing.T) (r *fstest.Run, vfs *VFS, fh *RWFileHandle, cleanup func()) {
-	return rwHandleCreateFlags(t, r, false, "file1", os.O_WRONLY|os.O_CREATE)
+	return rwHandleCreateFlags(t, false, "file1", os.O_WRONLY|os.O_CREATE)
 }
 
 // read data from the string
@@ -75,9 +70,8 @@ func rwReadString(t *testing.T, fh *RWFileHandle, n int) string {
 }
 
 func TestRWFileHandleMethodsRead(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, fh, cleanup := rwHandleCreateReadOnly(t)
-	vfs, fh := rwHandleCreateReadOnly(t, r)
+	defer cleanup()
-	defer cleanup(t, r, vfs)
 
 	// String
 	assert.Equal(t, "dir/file1 (rw)", fh.String())
@@ -123,9 +117,8 @@ func TestRWFileHandleMethodsRead(t *testing.T) {
 }
 
 func TestRWFileHandleSeek(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, fh, cleanup := rwHandleCreateReadOnly(t)
-	vfs, fh := rwHandleCreateReadOnly(t, r)
+	defer cleanup()
-	defer cleanup(t, r, vfs)
 
 	assert.Equal(t, fh.opened, false)
 
@@ -174,9 +167,8 @@ func TestRWFileHandleSeek(t *testing.T) {
 }
 
 func TestRWFileHandleReadAt(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, fh, cleanup := rwHandleCreateReadOnly(t)
-	vfs, fh := rwHandleCreateReadOnly(t, r)
+	defer cleanup()
-	defer cleanup(t, r, vfs)
 
 	// read from start
 	buf := make([]byte, 1)
@@ -225,9 +217,8 @@ func TestRWFileHandleReadAt(t *testing.T) {
 }
 
 func TestRWFileHandleFlushRead(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, fh, cleanup := rwHandleCreateReadOnly(t)
-	vfs, fh := rwHandleCreateReadOnly(t, r)
+	defer cleanup()
-	defer cleanup(t, r, vfs)
 
 	// Check Flush does nothing if read not called
 	err := fh.Flush()
@@ -255,9 +246,8 @@ func TestRWFileHandleFlushRead(t *testing.T) {
 }
 
 func TestRWFileHandleReleaseRead(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, fh, cleanup := rwHandleCreateReadOnly(t)
-	vfs, fh := rwHandleCreateReadOnly(t, r)
+	defer cleanup()
-	defer cleanup(t, r, vfs)
 
 	// Read data
 	buf := make([]byte, 256)
@@ -279,9 +269,8 @@ func TestRWFileHandleReleaseRead(t *testing.T) {
 /// ------------------------------------------------------------
 
 func TestRWFileHandleMethodsWrite(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, fh, cleanup := rwHandleCreateWriteOnly(t)
-	vfs, fh := rwHandleCreateWriteOnly(t, r)
+	defer cleanup()
-	defer cleanup(t, r, vfs)
 
 	// String
 	assert.Equal(t, "file1 (rw)", fh.String())
@@ -351,13 +340,13 @@ func TestRWFileHandleMethodsWrite(t *testing.T) {
 
 	// check the underlying r.Fremote but not the modtime
 	file1 := fstest.NewItem("file1", "hello world", t1)
+	vfs.WaitForWriters(waitForWritersDelay)
 	fstest.CheckListingWithPrecision(t, r.Fremote, []fstest.Item{file1}, []string{}, fs.ModTimeNotSupported)
 }
 
 func TestRWFileHandleWriteAt(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, fh, cleanup := rwHandleCreateWriteOnly(t)
-	vfs, fh := rwHandleCreateWriteOnly(t, r)
+	defer cleanup()
-	defer cleanup(t, r, vfs)
 
 	offset := func() int64 {
 		n, err := fh.Seek(0, io.SeekCurrent)
@@ -399,13 +388,13 @@ func TestRWFileHandleWriteAt(t *testing.T) {
 
 	// check the underlying r.Fremote but not the modtime
 	file1 := fstest.NewItem("file1", "hello world", t1)
+	vfs.WaitForWriters(waitForWritersDelay)
 	fstest.CheckListingWithPrecision(t, r.Fremote, []fstest.Item{file1}, []string{}, fs.ModTimeNotSupported)
 }
 
 func TestRWFileHandleWriteNoWrite(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, fh, cleanup := rwHandleCreateWriteOnly(t)
-	vfs, fh := rwHandleCreateWriteOnly(t, r)
+	defer cleanup()
-	defer cleanup(t, r, vfs)
 
 	// Close the file without writing to it
 	err := fh.Close()
@@ -433,13 +422,13 @@ func TestRWFileHandleWriteNoWrite(t *testing.T) {
 	// check the underlying r.Fremote but not the modtime
 	file1 := fstest.NewItem("file1", "", t1)
 	file2 := fstest.NewItem("file2", "", t1)
+	vfs.WaitForWriters(waitForWritersDelay)
 	fstest.CheckListingWithPrecision(t, r.Fremote, []fstest.Item{file1, file2}, []string{}, fs.ModTimeNotSupported)
 }
 
 func TestRWFileHandleFlushWrite(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, fh, cleanup := rwHandleCreateWriteOnly(t)
-	vfs, fh := rwHandleCreateWriteOnly(t, r)
+	defer cleanup()
-	defer cleanup(t, r, vfs)
 
 	// Check that the file has been create and is open
 	assert.True(t, fh.opened)
@@ -467,9 +456,8 @@ func TestRWFileHandleFlushWrite(t *testing.T) {
 }
 
 func TestRWFileHandleReleaseWrite(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, fh, cleanup := rwHandleCreateWriteOnly(t)
-	vfs, fh := rwHandleCreateWriteOnly(t, r)
+	defer cleanup()
-	defer cleanup(t, r, vfs)
 
 	// Write some data
 	n, err := fh.Write([]byte("hello"))
@@ -498,9 +486,8 @@ func assertSize(t *testing.T, vfs *VFS, fh *RWFileHandle, filepath string, size
 }
 
 func TestRWFileHandleSizeTruncateExisting(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, vfs, fh, cleanup := rwHandleCreateFlags(t, true, "dir/file1", os.O_WRONLY|os.O_TRUNC)
-	vfs, fh := rwHandleCreateFlags(t, r, true, "dir/file1", os.O_WRONLY|os.O_TRUNC)
+	defer cleanup()
-	defer cleanup(t, r, vfs)
 
 	// check initial size after opening
 	assertSize(t, vfs, fh, "dir/file1", 0)
@@ -521,9 +508,8 @@ func TestRWFileHandleSizeTruncateExisting(t *testing.T) {
 }
 
 func TestRWFileHandleSizeCreateExisting(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, vfs, fh, cleanup := rwHandleCreateFlags(t, true, "dir/file1", os.O_WRONLY|os.O_CREATE)
-	vfs, fh := rwHandleCreateFlags(t, r, true, "dir/file1", os.O_WRONLY|os.O_CREATE)
+	defer cleanup()
-	defer cleanup(t, r, vfs)
 
 	// check initial size after opening
 	assertSize(t, vfs, fh, "dir/file1", 16)
@@ -552,9 +538,8 @@ func TestRWFileHandleSizeCreateExisting(t *testing.T) {
 }
 
 func TestRWFileHandleSizeCreateNew(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, vfs, fh, cleanup := rwHandleCreateFlags(t, false, "file1", os.O_WRONLY|os.O_CREATE)
-	vfs, fh := rwHandleCreateFlags(t, r, false, "file1", os.O_WRONLY|os.O_CREATE)
+	defer cleanup()
-	defer cleanup(t, r, vfs)
 
 	// check initial size after opening
 	assertSize(t, vfs, fh, "file1", 0)
@@ -653,11 +638,11 @@ func testRWFileHandleOpenTest(t *testing.T, vfs *VFS, test *openTest) {
 }
 
 func TestRWFileHandleOpenTests(t *testing.T) {
-	r := fstest.NewRun(t)
 	opt := vfscommon.DefaultOpt
 	opt.CacheMode = vfscommon.CacheModeFull
-	vfs := New(r.Fremote, &opt)
+	opt.WriteBack = writeBackDelay
-	defer cleanup(t, r, vfs)
+	_, vfs, cleanup := newTestVFSOpt(t, &opt)
+	defer cleanup()
 
 	for _, test := range openTests {
 		t.Run(test.what, func(t *testing.T) {
@@ -668,12 +653,11 @@ func TestRWFileHandleOpenTests(t *testing.T) {
 
 // tests mod time on open files
 func TestRWFileModTimeWithOpenWriters(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, fh, cleanup := rwHandleCreateWriteOnly(t)
-	defer r.Finalise()
+	defer cleanup()
 	if !canSetModTime(t, r) {
-		return
+		t.Skip("can't set mod time")
 	}
-	vfs, fh := rwHandleCreateWriteOnly(t, r)
 
 	mtime := time.Date(2012, time.November, 18, 17, 32, 31, 0, time.UTC)
 
@@ -700,21 +684,21 @@ func TestRWFileModTimeWithOpenWriters(t *testing.T) {
 	}
 
 	file1 := fstest.NewItem("file1", "hi", mtime)
+	vfs.WaitForWriters(waitForWritersDelay)
 	fstest.CheckItems(t, r.Fremote, file1)
 }
 
 func TestRWCacheRename(t *testing.T) {
-	r := fstest.NewRun(t)
+	opt := vfscommon.DefaultOpt
-	defer r.Finalise()
+	opt.CacheMode = vfscommon.CacheModeFull
+	opt.WriteBack = writeBackDelay
+	r, vfs, cleanup := newTestVFSOpt(t, &opt)
+	defer cleanup()
 
 	if !operations.CanServerSideMove(r.Fremote) {
 		t.Skip("skip as can't rename files")
 	}
 
-	opt := vfscommon.DefaultOpt
-	opt.CacheMode = vfscommon.CacheModeFull
-	vfs := New(r.Fremote, &opt)
-
 	h, err := vfs.OpenFile("rename_me", os.O_WRONLY|os.O_CREATE, 0777)
 	require.NoError(t, err)
 	_, err = h.WriteString("hello")

vfs/vfs.go

@@ -265,7 +265,7 @@ func (vfs *VFS) FlushDirCache() {
 // time.Duration has elapsed
 func (vfs *VFS) WaitForWriters(timeout time.Duration) {
 	defer log.Trace(nil, "timeout=%v", timeout)("")
-	const tickTime = 1 * time.Second
+	tickTime := 10 * time.Millisecond
 	deadline := time.NewTimer(timeout)
 	defer deadline.Stop()
 	tick := time.NewTimer(tickTime)
@@ -273,18 +273,26 @@ func (vfs *VFS) WaitForWriters(timeout time.Duration) {
 	tick.Stop()
 	for {
 		writers := vfs.root.countActiveWriters()
-		if writers == 0 {
+		cacheInUse := 0
+		if vfs.cache != nil {
+			cacheInUse = vfs.cache.TotalInUse()
+		}
+		if writers == 0 && cacheInUse == 0 {
 			return
 		}
-		fs.Debugf(nil, "Still %d writers active, waiting %v", writers, tickTime)
+		fs.Debugf(nil, "Still %d writers active and %d cache items in use, waiting %v", writers, cacheInUse, tickTime)
 		tick.Reset(tickTime)
 		select {
 		case <-tick.C:
 			break
 		case <-deadline.C:
-			fs.Errorf(nil, "Exiting even though %d writers are active after %v", writers, timeout)
+			fs.Errorf(nil, "Exiting even though %d writers active and %d cache items in use after %v\n%s", writers, cacheInUse, timeout, vfs.cache.Dump())
 			return
 		}
+		tickTime *= 2
+		if tickTime > time.Second {
+			tickTime = time.Second
+		}
 	}
 }
 

vfs/vfs_case_test.go

@@ -36,10 +36,12 @@ func TestCaseSensitivity(t *testing.T) {
 	optCS := vfscommon.DefaultOpt
 	optCS.CaseInsensitive = false
 	vfsCS := New(r.Fremote, &optCS)
+	defer cleanupVFS(t, vfsCS)
 
 	optCI := vfscommon.DefaultOpt
 	optCI.CaseInsensitive = true
 	vfsCI := New(r.Fremote, &optCI)
+	defer cleanupVFS(t, vfsCI)
 
 	// Run basic checks that must pass on VFS of any type.
 	assertFileDataVFS(t, vfsCI, "FiLeA", "data1")

vfs/vfs_test.go

@@ -8,6 +8,7 @@ import (
 	"io"
 	"os"
 	"testing"
+	"time"
 
 	"github.com/pkg/errors"
 	_ "github.com/rclone/rclone/backend/all" // import all the backends
@@ -25,11 +26,41 @@ var (
 	t3 = fstest.Time("2011-12-30T12:59:59.000000000Z")
 )
 
+// Constants uses in the tests
+const (
+	writeBackDelay      = 100 * time.Millisecond // A short writeback delay for testing
+	waitForWritersDelay = 10 * time.Second       // time to wait for exiting writiers
+)
+
 // TestMain drives the tests
 func TestMain(m *testing.M) {
 	fstest.TestMain(m)
 }
 
+// Clean up a test VFS
+func cleanupVFS(t *testing.T, vfs *VFS) {
+	vfs.WaitForWriters(waitForWritersDelay)
+	err := vfs.CleanUp()
+	require.NoError(t, err)
+	vfs.Shutdown()
+}
+
+// Create a new VFS
+func newTestVFSOpt(t *testing.T, opt *vfscommon.Options) (r *fstest.Run, vfs *VFS, cleanup func()) {
+	r = fstest.NewRun(t)
+	vfs = New(r.Fremote, opt)
+	cleanup = func() {
+		cleanupVFS(t, vfs)
+		r.Finalise()
+	}
+	return r, vfs, cleanup
+}
+
+// Create a new VFS with default options
+func newTestVFS(t *testing.T) (r *fstest.Run, vfs *VFS, cleanup func()) {
+	return newTestVFSOpt(t, nil)
+}
+
 // Check baseHandle performs as advertised
 func TestVFSbaseHandle(t *testing.T) {
 	fh := baseHandle{}
@@ -97,31 +128,33 @@ func TestVFSbaseHandle(t *testing.T) {
 
 // TestNew sees if the New command works properly
 func TestVFSNew(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, cleanup := newTestVFS(t)
-	defer r.Finalise()
+	defer cleanup()
 
 	// Check making a VFS with nil options
-	vfs := New(r.Fremote, nil)
 	var defaultOpt = vfscommon.DefaultOpt
 	defaultOpt.DirPerms |= os.ModeDir
 	assert.Equal(t, vfs.Opt, defaultOpt)
 	assert.Equal(t, vfs.f, r.Fremote)
+}
 
-	// Check the initialisation
+// TestNew sees if the New command works properly
+func TestVFSNewWithOpts(t *testing.T) {
 	var opt = vfscommon.DefaultOpt
 	opt.DirPerms = 0777
 	opt.FilePerms = 0666
 	opt.Umask = 0002
-	vfs = New(r.Fremote, &opt)
+	_, vfs, cleanup := newTestVFSOpt(t, &opt)
+	defer cleanup()
+
 	assert.Equal(t, os.FileMode(0775)|os.ModeDir, vfs.Opt.DirPerms)
 	assert.Equal(t, os.FileMode(0664), vfs.Opt.FilePerms)
 }
 
 // TestRoot checks root directory is present and correct
 func TestVFSRoot(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, vfs, cleanup := newTestVFS(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs := New(r.Fremote, nil)
 
 	root, err := vfs.Root()
 	require.NoError(t, err)
@@ -131,9 +164,8 @@ func TestVFSRoot(t *testing.T) {
 }
 
 func TestVFSStat(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, cleanup := newTestVFS(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs := New(r.Fremote, nil)
 
 	file1 := r.WriteObject(context.Background(), "file1", "file1 contents", t1)
 	file2 := r.WriteObject(context.Background(), "dir/file2", "file2 contents", t2)
@@ -168,9 +200,8 @@ func TestVFSStat(t *testing.T) {
 }
 
 func TestVFSStatParent(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, cleanup := newTestVFS(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs := New(r.Fremote, nil)
 
 	file1 := r.WriteObject(context.Background(), "file1", "file1 contents", t1)
 	file2 := r.WriteObject(context.Background(), "dir/file2", "file2 contents", t2)
@@ -202,9 +233,8 @@ func TestVFSStatParent(t *testing.T) {
 }
 
 func TestVFSOpenFile(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, cleanup := newTestVFS(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs := New(r.Fremote, nil)
 
 	file1 := r.WriteObject(context.Background(), "file1", "file1 contents", t1)
 	file2 := r.WriteObject(context.Background(), "dir/file2", "file2 contents", t2)
@@ -238,13 +268,13 @@ func TestVFSOpenFile(t *testing.T) {
 }
 
 func TestVFSRename(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, cleanup := newTestVFS(t)
-	defer r.Finalise()
+	defer cleanup()
+
 	features := r.Fremote.Features()
 	if features.Move == nil && features.Copy == nil {
-		return // skip as can't rename files
+		t.Skip("skip as can't rename files")
 	}
-	vfs := New(r.Fremote, nil)
 
 	file1 := r.WriteObject(context.Background(), "dir/file2", "file2 contents", t2)
 	fstest.CheckItems(t, r.Fremote, file1)
@@ -267,9 +297,8 @@ func TestVFSRename(t *testing.T) {
 }
 
 func TestVFSStatfs(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, cleanup := newTestVFS(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs := New(r.Fremote, nil)
 
 	// pre-conditions
 	assert.Nil(t, vfs.usage)

vfs/vfscache/cache.go

@@ -18,7 +18,6 @@ import (
 	fscache "github.com/rclone/rclone/fs/cache"
 	"github.com/rclone/rclone/fs/config"
 	"github.com/rclone/rclone/fs/hash"
-	"github.com/rclone/rclone/fs/log"
 	"github.com/rclone/rclone/fs/operations"
 	"github.com/rclone/rclone/lib/file"
 	"github.com/rclone/rclone/vfs/vfscommon"
@@ -43,6 +42,7 @@ type Cache struct {
 	metaRoot   string             // root of the cache metadata directory
 	hashType   hash.Type          // hash to use locally and remotely
 	hashOption *fs.HashesOption   // corresponding OpenOption
+	writeback  *writeBack         // holds Items for writeback
 
 	mu   sync.Mutex       // protects the following variables
 	item map[string]*Item // files/directories in the cache
@@ -87,6 +87,7 @@ func New(ctx context.Context, fremote fs.Fs, opt *vfscommon.Options) (*Cache, er
 		item:       make(map[string]*Item),
 		hashType:   hashType,
 		hashOption: hashOption,
+		writeback:  newWriteBack(ctx, opt),
 	}
 
 	// Make sure cache directories exist
@@ -200,6 +201,20 @@ func (c *Cache) InUse(name string) bool {
 	return item.inUse()
 }
 
+// DirtyItem the Item if it exists in the cache and is Dirty
+//
+// name should be a remote path not an osPath
+func (c *Cache) DirtyItem(name string) (item *Item) {
+	name = clean(name)
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	item = c.item[name]
+	if item != nil && !item.IsDirty() {
+		item = nil
+	}
+	return item
+}
+
 // get gets a file name from the cache or creates a new one
 //
 // It returns the item and found as to whether this item was found in
@@ -224,20 +239,14 @@ func (c *Cache) Item(name string) (item *Item) {
 	return item
 }
 
-// Exists checks to see if the file exists in the cache or not
+// Exists checks to see if the file exists in the cache or not.
 //
-// FIXME check the metadata exists here too?
+// This is done by bringing the item into the cache which will
+// validate the backing file and metadata and then asking if the Item
+// exists or not.
 func (c *Cache) Exists(name string) bool {
-	osPath := c.toOSPath(name)
+	item, _ := c.get(name)
-	fi, err := os.Stat(osPath)
+	return item.Exists()
-	if err != nil {
-		return false
-	}
-	// checks for non-regular files (e.g. directories, symlinks, devices, etc.)
-	if !fi.Mode().IsRegular() {
-		return false
-	}
-	return true
 }
 
 // rename with os.Rename and more checking
@@ -300,8 +309,13 @@ func (c *Cache) Rename(name string, newName string, newObj fs.Object) (err error
 
 // Remove should be called if name is deleted
 func (c *Cache) Remove(name string) {
-	item, _ := c.get(name)
+	name = clean(name)
+	c.mu.Lock()
+	item, _ := c._get(name)
+	delete(c.item, name)
+	c.mu.Unlock()
 	item.remove("file deleted")
+
 }
 
 // SetModTime should be called to set the modification time of the cache file
@@ -506,9 +520,30 @@ func (c *Cache) cleaner(ctx context.Context) {
 	}
 }
 
-// Check the local file is up to date in the cache
+// TotalInUse returns the number of items in the cache which are InUse
-func (c *Cache) Check(ctx context.Context, o fs.Object, remote string) (err error) {
+func (c *Cache) TotalInUse() (n int) {
-	defer log.Trace(o, "remote=%q", remote)("err=%v", &err)
+	c.mu.Lock()
-	item, _ := c.get(remote)
+	defer c.mu.Unlock()
-	return item.checkObject(o)
+	for _, item := range c.item {
+		if item.inUse() {
+			n++
+		}
+	}
+	return n
+}
+
+// Dump the cache into a string for debugging purposes
+func (c *Cache) Dump() string {
+	if c == nil {
+		return "Cache: <nil>\n"
+	}
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	var out strings.Builder
+	out.WriteString("Cache{\n")
+	for name, item := range c.item {
+		fmt.Fprintf(&out, "\t%q: %+v,\n", name, item)
+	}
+	out.WriteString("}\n")
+	return out.String()
 }

vfs/vfscache/cache_test.go

@@ -33,22 +33,59 @@ func itemAsString(c *Cache) []string {
 	return out
 }
 
-func TestCacheNew(t *testing.T) {
+// open an item and write to it
-	r := fstest.NewRun(t)
+func itemWrite(t *testing.T, item *Item, contents string) {
-	defer r.Finalise()
+	require.NoError(t, item.Open(nil))
+	_, err := item.WriteAt([]byte(contents), 0)
+	require.NoError(t, err)
+}
+
+func assertPathNotExist(t *testing.T, path string) {
+	_, err := os.Stat(path)
+	assert.True(t, os.IsNotExist(err))
+}
+
+func assertPathExist(t *testing.T, path string) os.FileInfo {
+	fi, err := os.Stat(path)
+	assert.NoError(t, err)
+	return fi
+}
+
+func newTestCacheOpt(t *testing.T, opt vfscommon.Options) (r *fstest.Run, c *Cache, cleanup func()) {
+	r = fstest.NewRun(t)
 
 	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
 
-	// FIXME need to be writing to the actual file here
-	// need a item.WriteAt/item.ReadAt method I think
-
-	// Disable the cache cleaner as it interferes with these tests
-	opt := vfscommon.DefaultOpt
-	opt.CachePollInterval = 0
 	c, err := New(ctx, r.Fremote, &opt)
 	require.NoError(t, err)
 
+	cleanup = func() {
+		err := c.CleanUp()
+		require.NoError(t, err)
+		assertPathNotExist(t, c.root)
+		cancel()
+		r.Finalise()
+	}
+
+	return r, c, cleanup
+}
+
+func newTestCache(t *testing.T) (r *fstest.Run, c *Cache, cleanup func()) {
+	opt := vfscommon.DefaultOpt
+
+	// Disable the cache cleaner as it interferes with these tests
+	opt.CachePollInterval = 0
+
+	// Enable synchronous write
+	opt.WriteBack = 0
+
+	return newTestCacheOpt(t, opt)
+}
+
+func TestCacheNew(t *testing.T) {
+	r, c, cleanup := newTestCache(t)
+	defer cleanup()
+
 	assert.Contains(t, c.root, "vfs")
 	assert.Contains(t, c.fcache.Root(), filepath.Base(r.Fremote.Root()))
 	assert.Equal(t, []string(nil), itemAsString(c))
@@ -59,8 +96,7 @@ func TestCacheNew(t *testing.T) {
 	assert.Equal(t, "potato", filepath.Base(p))
 	assert.Equal(t, []string(nil), itemAsString(c))
 
-	fi, err := os.Stat(filepath.Dir(p))
+	fi := assertPathExist(t, filepath.Dir(p))
-	require.NoError(t, err)
 	assert.True(t, fi.IsDir())
 
 	// get
@@ -85,13 +121,6 @@ func TestCacheNew(t *testing.T) {
 	require.NoError(t, potato.Truncate(5))
 	atime := time.Now()
 	potato.info.ATime = atime
-	// err = ioutil.WriteFile(p, []byte("hello"), 0600)
-	// require.NoError(t, err)
-
-	// read its atime
-
-	// updateAtimes
-	//potato.ATime = time.Now().Add(-24 * time.Hour)
 
 	assert.Equal(t, []string{
 		`name="potato" opens=1 size=5`,
@@ -100,8 +129,7 @@ func TestCacheNew(t *testing.T) {
 
 	// try purging with file open
 	c.purgeOld(10 * time.Second)
-	// _, err = os.Stat(p)
+	assertPathExist(t, p)
-	// assert.NoError(t, err)
 
 	// close
 	assert.Equal(t, []string{
@@ -121,35 +149,19 @@ func TestCacheNew(t *testing.T) {
 
 	// try purging with file closed
 	c.purgeOld(10 * time.Second)
-	// ...nothing should happend
+	assertPathExist(t, p)
-	// _, err = os.Stat(p)
-	// assert.NoError(t, err)
 
 	//.. purge again with -ve age
 	c.purgeOld(-10 * time.Second)
-	_, err = os.Stat(p)
+	assertPathNotExist(t, p)
-	assert.True(t, os.IsNotExist(err))
 
 	// clean - have tested the internals already
 	c.clean()
-
-	// cleanup
-	err = c.CleanUp()
-	require.NoError(t, err)
-	_, err = os.Stat(c.root)
-	assert.True(t, os.IsNotExist(err))
 }
 
 func TestCacheOpens(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, c, cleanup := newTestCache(t)
-	defer r.Finalise()
+	defer cleanup()
-
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	c, err := New(ctx, r.Fremote, &vfscommon.DefaultOpt)
-	require.NoError(t, err)
-	defer func() { require.NoError(t, c.CleanUp()) }()
 
 	assert.Equal(t, []string(nil), itemAsString(c))
 	potato := c.Item("potato")
@@ -197,18 +209,8 @@ func TestCacheOpens(t *testing.T) {
 
 // test the open, mkdir, purge, close, purge sequence
 func TestCacheOpenMkdir(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, c, cleanup := newTestCache(t)
-	defer r.Finalise()
+	defer cleanup()
-
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	// Disable the cache cleaner as it interferes with these tests
-	opt := vfscommon.DefaultOpt
-	opt.CachePollInterval = 0
-	c, err := New(ctx, r.Fremote, &opt)
-	require.NoError(t, err)
-	defer func() { require.NoError(t, c.CleanUp()) }()
 
 	// open
 	potato := c.Item("sub/potato")
@@ -227,16 +229,14 @@ func TestCacheOpenMkdir(t *testing.T) {
 	}, itemAsString(c))
 
 	// test directory exists
-	fi, err := os.Stat(filepath.Dir(p))
+	fi := assertPathExist(t, filepath.Dir(p))
-	require.NoError(t, err)
 	assert.True(t, fi.IsDir())
 
 	// clean the cache
 	c.purgeOld(-10 * time.Second)
 
 	// test directory still exists
-	fi, err = os.Stat(filepath.Dir(p))
+	fi = assertPathExist(t, filepath.Dir(p))
-	require.NoError(t, err)
 	assert.True(t, fi.IsDir())
 
 	// close
@@ -252,39 +252,23 @@ func TestCacheOpenMkdir(t *testing.T) {
 
 	assert.Equal(t, []string(nil), itemAsString(c))
 
-	// FIXME test directory does not exist
+	// test directory does not exist
-	// _, err = os.Stat(filepath.Dir(p))
+	assertPathNotExist(t, filepath.Dir(p))
-	// require.True(t, os.IsNotExist(err))
 }
 
 func TestCachePurgeOld(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, c, cleanup := newTestCache(t)
-	defer r.Finalise()
+	defer cleanup()
-
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	c, err := New(ctx, r.Fremote, &vfscommon.DefaultOpt)
-	require.NoError(t, err)
-	defer func() { require.NoError(t, c.CleanUp()) }()
 
 	// Test funcs
 	var removed []string
-	//removedDir := true
 	removeFile := func(item *Item) {
 		removed = append(removed, item.name)
 		item._remove("TestCachePurgeOld")
 	}
-	// removeDir := func(name string) bool {
-	// 	if removedDir {
-	// 		removed = append(removed, filepath.ToSlash(name)+"/")
-	// 	}
-	// 	return removedDir
-	// }
 
 	removed = nil
 	c._purgeOld(-10*time.Second, removeFile)
-	// FIXME c._purgeEmptyDirs(removeDir)
 	assert.Equal(t, []string(nil), removed)
 
 	potato2 := c.Item("sub/dir2/potato2")
@@ -300,9 +284,7 @@ func TestCachePurgeOld(t *testing.T) {
 	}, itemAsString(c))
 
 	removed = nil
-	// removedDir = true
 	c._purgeOld(-10*time.Second, removeFile)
-	// FIXME c._purgeEmptyDirs(removeDir)
 	assert.Equal(t, []string{
 		"sub/dir2/potato2",
 	}, removed)
@@ -310,9 +292,7 @@ func TestCachePurgeOld(t *testing.T) {
 	require.NoError(t, potato.Close(nil))
 
 	removed = nil
-	// removedDir = true
 	c._purgeOld(-10*time.Second, removeFile)
-	// FIXME c._purgeEmptyDirs(removeDir)
 	assert.Equal(t, []string(nil), removed)
 
 	require.NoError(t, potato.Close(nil))
@@ -322,9 +302,7 @@ func TestCachePurgeOld(t *testing.T) {
 	}, itemAsString(c))
 
 	removed = nil
-	// removedDir = false
 	c._purgeOld(10*time.Second, removeFile)
-	// FIXME c._purgeEmptyDirs(removeDir)
 	assert.Equal(t, []string(nil), removed)
 
 	assert.Equal(t, []string{
@@ -332,9 +310,7 @@ func TestCachePurgeOld(t *testing.T) {
 	}, itemAsString(c))
 
 	removed = nil
-	// removedDir = true
 	c._purgeOld(-10*time.Second, removeFile)
-	// FIXME c._purgeEmptyDirs(removeDir)
 	assert.Equal(t, []string{
 		"sub/dir/potato",
 	}, removed)
@@ -343,17 +319,8 @@ func TestCachePurgeOld(t *testing.T) {
 }
 
 func TestCachePurgeOverQuota(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, c, cleanup := newTestCache(t)
-	defer r.Finalise()
+	defer cleanup()
-
-	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-
-	// Disable the cache cleaner as it interferes with these tests
-	opt := vfscommon.DefaultOpt
-	opt.CachePollInterval = 0
-	c, err := New(ctx, r.Fremote, &opt)
-	require.NoError(t, err)
 
 	// Test funcs
 	var removed []string
@@ -376,12 +343,10 @@ func TestCachePurgeOverQuota(t *testing.T) {
 
 	// Make some test files
 	potato := c.Item("sub/dir/potato")
-	require.NoError(t, potato.Open(nil))
+	itemWrite(t, potato, "hello")
-	require.NoError(t, potato.Truncate(5))
 
 	potato2 := c.Item("sub/dir2/potato2")
-	require.NoError(t, potato2.Open(nil))
+	itemWrite(t, potato2, "hello2")
-	require.NoError(t, potato2.Truncate(6))
 
 	assert.Equal(t, []string{
 		`name="sub/dir/potato" opens=1 size=5`,
@@ -407,7 +372,6 @@ func TestCachePurgeOverQuota(t *testing.T) {
 
 	// make potato2 definitely after potato
 	t1 := time.Now().Add(10 * time.Second)
-	require.NoError(t, potato2.Truncate(6))
 	potato2.info.ATime = t1
 
 	// Check only potato removed to get below quota
@@ -470,3 +434,210 @@ func TestCachePurgeOverQuota(t *testing.T) {
 	assert.Equal(t, int64(0), c.used)
 	assert.Equal(t, []string(nil), itemAsString(c))
 }
+
+func TestCacheInUse(t *testing.T) {
+	_, c, cleanup := newTestCache(t)
+	defer cleanup()
+
+	assert.False(t, c.InUse("potato"))
+
+	potato := c.Item("potato")
+
+	assert.False(t, c.InUse("potato"))
+
+	require.NoError(t, potato.Open(nil))
+
+	assert.True(t, c.InUse("potato"))
+
+	require.NoError(t, potato.Close(nil))
+
+	assert.False(t, c.InUse("potato"))
+}
+
+func TestCacheDirtyItem(t *testing.T) {
+	_, c, cleanup := newTestCache(t)
+	defer cleanup()
+
+	assert.Nil(t, c.DirtyItem("potato"))
+
+	potato := c.Item("potato")
+
+	assert.Nil(t, c.DirtyItem("potato"))
+
+	require.NoError(t, potato.Open(nil))
+	require.NoError(t, potato.Truncate(5))
+
+	assert.Equal(t, potato, c.DirtyItem("potato"))
+
+	require.NoError(t, potato.Close(nil))
+
+	assert.Nil(t, c.DirtyItem("potato"))
+}
+
+func TestCacheExistsAndRemove(t *testing.T) {
+	_, c, cleanup := newTestCache(t)
+	defer cleanup()
+
+	assert.False(t, c.Exists("potato"))
+
+	potato := c.Item("potato")
+
+	assert.False(t, c.Exists("potato"))
+
+	require.NoError(t, potato.Open(nil))
+
+	assert.True(t, c.Exists("potato"))
+
+	require.NoError(t, potato.Close(nil))
+
+	assert.True(t, c.Exists("potato"))
+
+	c.Remove("potato")
+
+	assert.False(t, c.Exists("potato"))
+
+}
+
+func TestCacheRename(t *testing.T) {
+	_, c, cleanup := newTestCache(t)
+	defer cleanup()
+
+	// setup
+
+	assert.False(t, c.Exists("potato"))
+	potato := c.Item("potato")
+	require.NoError(t, potato.Open(nil))
+	require.NoError(t, potato.Close(nil))
+	assert.True(t, c.Exists("potato"))
+
+	osPath := c.toOSPath("potato")
+	osPathMeta := c.toOSPathMeta("potato")
+	assertPathExist(t, osPath)
+	assertPathExist(t, osPathMeta)
+
+	// rename potato -> newPotato
+
+	require.NoError(t, c.Rename("potato", "newPotato", nil))
+	assertPathNotExist(t, osPath)
+	assertPathNotExist(t, osPathMeta)
+	assert.False(t, c.Exists("potato"))
+
+	osPath = c.toOSPath("newPotato")
+	osPathMeta = c.toOSPathMeta("newPotato")
+	assertPathExist(t, osPath)
+	assertPathExist(t, osPathMeta)
+	assert.True(t, c.Exists("newPotato"))
+
+	// rename newPotato -> sub/newPotato
+
+	require.NoError(t, c.Rename("newPotato", "sub/newPotato", nil))
+	assertPathNotExist(t, osPath)
+	assertPathNotExist(t, osPathMeta)
+	assert.False(t, c.Exists("potato"))
+
+	osPath = c.toOSPath("sub/newPotato")
+	osPathMeta = c.toOSPathMeta("sub/newPotato")
+	assertPathExist(t, osPath)
+	assertPathExist(t, osPathMeta)
+	assert.True(t, c.Exists("sub/newPotato"))
+
+	// remove
+
+	c.Remove("sub/newPotato")
+	assertPathNotExist(t, osPath)
+	assertPathNotExist(t, osPathMeta)
+	assert.False(t, c.Exists("sub/newPotato"))
+
+	// non existent file - is ignored
+	assert.NoError(t, c.Rename("nonexist", "nonexist2", nil))
+}
+
+func TestCacheCleaner(t *testing.T) {
+	opt := vfscommon.DefaultOpt
+	opt.CachePollInterval = 10 * time.Millisecond
+	opt.CacheMaxAge = 20 * time.Millisecond
+	_, c, cleanup := newTestCacheOpt(t, opt)
+	defer cleanup()
+
+	time.Sleep(2 * opt.CachePollInterval)
+
+	potato := c.Item("potato")
+	potato2, found := c.get("potato")
+	assert.Equal(t, potato, potato2)
+	assert.True(t, found)
+
+	time.Sleep(10 * opt.CachePollInterval)
+
+	potato2, found = c.get("potato")
+	assert.NotEqual(t, potato, potato2)
+	assert.False(t, found)
+}
+
+func TestCacheSetModTime(t *testing.T) {
+	_, c, cleanup := newTestCache(t)
+	defer cleanup()
+
+	t1 := time.Date(2010, 1, 2, 3, 4, 5, 9, time.UTC)
+
+	potato := c.Item("potato")
+	require.NoError(t, potato.Open(nil))
+	require.NoError(t, potato.Truncate(5))
+	require.NoError(t, potato.Close(nil))
+
+	c.SetModTime("potato", t1)
+	osPath := potato.c.toOSPath("potato")
+	fi, err := os.Stat(osPath)
+	require.NoError(t, err)
+
+	fstest.AssertTimeEqualWithPrecision(t, "potato", t1, fi.ModTime(), time.Second)
+}
+
+func TestCacheTotaInUse(t *testing.T) {
+	_, c, cleanup := newTestCache(t)
+	defer cleanup()
+
+	assert.Equal(t, int(0), c.TotalInUse())
+
+	potato := c.Item("potato")
+	assert.Equal(t, int(0), c.TotalInUse())
+
+	require.NoError(t, potato.Open(nil))
+	assert.Equal(t, int(1), c.TotalInUse())
+
+	require.NoError(t, potato.Truncate(5))
+	assert.Equal(t, int(1), c.TotalInUse())
+
+	potato2 := c.Item("potato2")
+	assert.Equal(t, int(1), c.TotalInUse())
+
+	require.NoError(t, potato2.Open(nil))
+	assert.Equal(t, int(2), c.TotalInUse())
+
+	require.NoError(t, potato2.Close(nil))
+	assert.Equal(t, int(1), c.TotalInUse())
+
+	require.NoError(t, potato.Close(nil))
+	assert.Equal(t, int(0), c.TotalInUse())
+}
+
+func TestCacheDump(t *testing.T) {
+	_, c, cleanup := newTestCache(t)
+	defer cleanup()
+
+	out := (*Cache)(nil).Dump()
+	assert.Equal(t, "Cache: <nil>\n", out)
+
+	out = c.Dump()
+	assert.Equal(t, "Cache{\n}\n", out)
+
+	c.Item("potato")
+
+	out = c.Dump()
+	want := "Cache{\n\t\"potato\": "
+	assert.Equal(t, want, out[:len(want)])
+
+	c.Remove("potato")
+
+	out = c.Dump()
+	assert.Equal(t, "Cache{\n}\n", out)
+}

vfs/vfscache/downloader.go

@@ -60,11 +60,12 @@ func newDownloader(item *Item, fcache fs.Fs, remote string, src fs.Object) (dl *
 	if err == nil {
 		// do nothing
 	} else if os.IsNotExist(err) {
-		fs.Debugf(src, "creating empty file")
+		return nil, errors.New("vfs cache: internal error: newDownloader: called before Item.Open")
-		err = item._truncateToCurrentSize()
+		// fs.Debugf(src, "creating empty file")
-		if err != nil {
+		// err = item._truncateToCurrentSize()
-			return nil, errors.Wrap(err, "newDownloader: failed to create empty file")
+		// if err != nil {
-		}
+		// 	return nil, errors.Wrap(err, "newDownloader: failed to create empty file")
+		// }
 	} else {
 		return nil, errors.Wrap(err, "newDownloader: failed to stat cache file")
 	}

vfs/vfscache/item.go

@@ -145,6 +145,13 @@ func (item *Item) getATime() time.Time {
 	return item.info.ATime
 }
 
+// getName returns the name of the item
+func (item *Item) getName() string {
+	item.mu.Lock()
+	defer item.mu.Unlock()
+	return item.name
+}
+
 // getDiskSize returns the size on disk (approximately) of the item
 //
 // We return the sizes of the chunks we have fetched, however there is
@@ -374,6 +381,13 @@ func (item *Item) Dirty() {
 	item.mu.Unlock()
 }
 
+// IsDirty returns true if the item is dirty
+func (item *Item) IsDirty() bool {
+	item.mu.Lock()
+	defer item.mu.Unlock()
+	return item.metaDirty || item.info.Dirty
+}
+
 // Open the local file from the object passed in (which may be nil)
 // which implies we are about to create the file
 func (item *Item) Open(o fs.Object) (err error) {
@@ -445,10 +459,9 @@ func (item *Item) Open(o fs.Object) (err error) {
 // Store stores the local cache file to the remote object, returning
 // the new remote object. objOld is the old object if known.
 //
-// call with item lock held
+// Call with lock held
-func (item *Item) _store() (err error) {
+func (item *Item) _store(ctx context.Context, storeFn StoreFn) (err error) {
 	defer log.Trace(item.name, "item=%p", item)("err=%v", &err)
-	ctx := context.Background()
 
 	// Ensure any segments not transferred are brought in
 	err = item._ensure(0, item.info.Size)
@@ -462,23 +475,51 @@ func (item *Item) _store() (err error) {
 		return errors.Wrap(err, "vfs cache: failed to find cache file")
 	}
 
+	item.mu.Unlock()
 	o, err := operations.Copy(ctx, item.c.fremote, item.o, item.name, cacheObj)
+	item.mu.Lock()
 	if err != nil {
 		return errors.Wrap(err, "vfs cache: failed to transfer file from cache to remote")
 	}
 	item.o = o
 	item._updateFingerprint()
+	item.info.Dirty = false
+	err = item._save()
+	if err != nil {
+		fs.Errorf(item.name, "Failed to write metadata file: %v", err)
+	}
+	if storeFn != nil && item.o != nil {
+		// Write the object back to the VFS layer as last
+		// thing we do with mutex unlocked
+		item.mu.Unlock()
+		storeFn(item.o)
+		item.mu.Lock()
+	}
 	return nil
 }
 
+// Store stores the local cache file to the remote object, returning
+// the new remote object. objOld is the old object if known.
+func (item *Item) store(ctx context.Context, storeFn StoreFn) (err error) {
+	item.mu.Lock()
+	defer item.mu.Unlock()
+	return item._store(ctx, storeFn)
+}
+
 // Close the cache file
 func (item *Item) Close(storeFn StoreFn) (err error) {
 	defer log.Trace(item.o, "Item.Close")("err=%v", &err)
 	var (
-		downloader *downloader
+		downloader    *downloader
-		o          fs.Object
+		syncWriteBack = item.c.opt.WriteBack <= 0
 	)
-	// close downloader and set item with mutex unlocked
+	// FIXME need to unlock to kill downloader - should we
+	// re-arrange locking so this isn't necessary?  maybe
+	// downloader should use the item mutex for locking? or put a
+	// finer lock on Rs?
+	//
+	// close downloader with mutex unlocked
+	// downloader.Write calls ensure which needs the lock
 	defer func() {
 		if downloader != nil {
 			closeErr := downloader.close(nil)
@@ -486,9 +527,11 @@ func (item *Item) Close(storeFn StoreFn) (err error) {
 				err = closeErr
 			}
 		}
-		if err == nil && storeFn != nil && o != nil {
+		// save the metadata once more since it may be dirty
-			// Write the object back to the VFS layer
+		// after the downloader
-			storeFn(item.o)
+		saveErr := item._save()
+		if saveErr != nil && err == nil {
+			err = errors.Wrap(saveErr, "close failed to save item")
 		}
 	}()
 	item.mu.Lock()
@@ -533,15 +576,14 @@ func (item *Item) Close(storeFn StoreFn) (err error) {
 
 	// upload the file to backing store if changed
 	if item.info.Dirty {
-		fs.Debugf(item.name, "item changed - writeback")
+		fs.Debugf(item.name, "item changed - writeback in %v", item.c.opt.WriteBack)
-		err = item._store()
+		if syncWriteBack {
-		if err != nil {
+			// do synchronous writeback
-			fs.Errorf(item.name, "%v", err)
+			err = item._store(context.Background(), storeFn)
-			return err
+		} else {
+			// asynchronous writeback
+			item.c.writeback.add(item, storeFn)
 		}
-		fs.Debugf(item.o, "transferred to remote")
-		item.info.Dirty = false
-		o = item.o
 	}
 
 	return err
@@ -590,16 +632,6 @@ func (item *Item) _checkObject(o fs.Object) error {
 	return nil
 }
 
-// check the fingerprint of an object and update the item or delete
-// the cached file accordingly.
-//
-// It ensures the file is the correct size for the object
-func (item *Item) checkObject(o fs.Object) error {
-	item.mu.Lock()
-	defer item.mu.Unlock()
-	return item._checkObject(o)
-}
-
 // remove the cached file
 //
 // call with lock held
@@ -760,6 +792,10 @@ func (item *Item) setModTime(modTime time.Time) {
 	item.mu.Lock()
 	item._updateFingerprint()
 	item._setModTime(modTime)
+	err := item._save()
+	if err != nil {
+		fs.Errorf(item.name, "vfs cache: setModTime: failed to save item info: %v", err)
+	}
 	item.mu.Unlock()
 }
 
@@ -796,6 +832,10 @@ func (item *Item) WriteAt(b []byte, off int64) (n int, err error) {
 	if n > 0 {
 		item._dirty()
 	}
+	end := off + int64(n)
+	if end > item.info.Size {
+		item.info.Size = end
+	}
 	item.mu.Unlock()
 	return n, err
 }

vfs/vfscache/writeback.go

@@ -0,0 +1,311 @@
+// This keeps track of the files which need to be written back
+
+package vfscache
+
+import (
+	"container/heap"
+	"context"
+	"sync"
+	"time"
+
+	"github.com/rclone/rclone/fs"
+	"github.com/rclone/rclone/vfs/vfscommon"
+)
+
+const (
+	uploadDelay       = 10 * time.Second // delay betwen upload attempts
+	maxUploadAttempts = 10               // max number of times to try to upload
+)
+
+// writeBack keeps track of the items which need to be written back to the disk at some point
+type writeBack struct {
+	mu      sync.Mutex
+	items   writeBackItems           // priority queue of *writeBackItem
+	lookup  map[*Item]*writeBackItem // for getting a *writeBackItem from a *Item
+	opt     *vfscommon.Options       // VFS options
+	timer   *time.Timer              // next scheduled time for the uploader
+	kick    chan struct{}            // send on this channel to wake up the uploader
+	uploads int                      // number of uploads in progress
+}
+
+// make a new writeBack
+//
+// cancel the context to stop the background goroutine
+func newWriteBack(ctx context.Context, opt *vfscommon.Options) *writeBack {
+	wb := &writeBack{
+		items:  writeBackItems{},
+		lookup: make(map[*Item]*writeBackItem),
+		opt:    opt,
+		timer:  time.NewTimer(time.Second),
+		kick:   make(chan struct{}, 1),
+	}
+	wb.timer.Stop()
+	heap.Init(&wb.items)
+	go wb.uploader(ctx)
+	return wb
+}
+
+// writeBackItem stores an Item awaiting writeback
+//
+// writeBack.mu must be held to manipulate this
+type writeBackItem struct {
+	index     int                // index into the priority queue for update
+	item      *Item              // Item that needs writeback
+	expiry    time.Time          // When this expires we will write it back
+	uploading bool               // If we are uploading the item
+	cancel    context.CancelFunc // To cancel the upload with
+	storeFn   StoreFn            // To write the object back with
+	tries     int                // number of times we have tried to upload
+	delay     time.Duration      // delay between upload attempts
+}
+
+// A writeBackItems implements a priority queue by implementing
+// heap.Interface and holds writeBackItems.
+type writeBackItems []*writeBackItem
+
+func (ws writeBackItems) Len() int { return len(ws) }
+
+func (ws writeBackItems) Less(i, j int) bool {
+	return ws[i].expiry.Sub(ws[j].expiry) < 0
+}
+
+func (ws writeBackItems) Swap(i, j int) {
+	ws[i], ws[j] = ws[j], ws[i]
+	ws[i].index = i
+	ws[j].index = j
+}
+
+func (ws *writeBackItems) Push(x interface{}) {
+	n := len(*ws)
+	item := x.(*writeBackItem)
+	item.index = n
+	*ws = append(*ws, item)
+}
+
+func (ws *writeBackItems) Pop() interface{} {
+	old := *ws
+	n := len(old)
+	item := old[n-1]
+	old[n-1] = nil  // avoid memory leak
+	item.index = -1 // for safety
+	*ws = old[0 : n-1]
+	return item
+}
+
+// update modifies the expiry of an Item in the queue.
+//
+// call with lock held
+func (ws *writeBackItems) _update(item *writeBackItem, expiry time.Time) {
+	item.expiry = expiry
+	heap.Fix(ws, item.index)
+}
+
+// return a new expiry time based from now until the WriteBack timeout
+//
+// call with lock held
+func (wb *writeBack) _newExpiry() time.Time {
+	expiry := time.Now()
+	if wb.opt.WriteBack > 0 {
+		expiry = expiry.Add(wb.opt.WriteBack)
+	}
+	return expiry
+}
+
+// make a new writeBackItem
+//
+// call with the lock held
+func (wb *writeBack) _newItem(item *Item) *writeBackItem {
+	wbItem := &writeBackItem{
+		item:   item,
+		expiry: wb._newExpiry(),
+		delay:  uploadDelay,
+	}
+	wb._addItem(wbItem)
+	wb._pushItem(wbItem)
+	return wbItem
+}
+
+// add a writeBackItem to the lookup map
+//
+// call with the lock held
+func (wb *writeBack) _addItem(wbItem *writeBackItem) {
+	wb.lookup[wbItem.item] = wbItem
+}
+
+// delete a writeBackItem from the lookup map
+//
+// call with the lock held
+func (wb *writeBack) _delItem(wbItem *writeBackItem) {
+	delete(wb.lookup, wbItem.item)
+}
+
+// pop a writeBackItem from the items heap
+//
+// call with the lock held
+func (wb *writeBack) _popItem() (wbItem *writeBackItem) {
+	return heap.Pop(&wb.items).(*writeBackItem)
+}
+
+// push a writeBackItem onto the items heap
+//
+// call with the lock held
+func (wb *writeBack) _pushItem(wbItem *writeBackItem) {
+	heap.Push(&wb.items, wbItem)
+}
+
+// peek the oldest writeBackItem - may be nil
+//
+// call with the lock held
+func (wb *writeBack) _peekItem() (wbItem *writeBackItem) {
+	if len(wb.items) == 0 {
+		return nil
+	}
+	return wb.items[0]
+}
+
+// reset the timer which runs the expiries
+func (wb *writeBack) _resetTimer() {
+	wbItem := wb._peekItem()
+	if wbItem == nil {
+		wb.timer.Stop()
+	} else {
+		dt := time.Until(wbItem.expiry)
+		if dt < 0 {
+			dt = 0
+		}
+		wb.timer.Reset(dt)
+	}
+}
+
+// add adds an item to the writeback queue or resets its timer if it
+// is already there
+func (wb *writeBack) add(item *Item, storeFn StoreFn) {
+	wb.mu.Lock()
+	defer wb.mu.Unlock()
+
+	wbItem, ok := wb.lookup[item]
+	if !ok {
+		wbItem = wb._newItem(item)
+	} else {
+		if wbItem.uploading {
+			// We are uploading already so cancel the upload
+			wb._cancelUpload(wbItem)
+		}
+		// Kick the timer on
+		wb.items._update(wbItem, wb._newExpiry())
+	}
+	wbItem.storeFn = storeFn
+	wb._resetTimer()
+}
+
+// kick the upload checker
+//
+// This should be called at the end of uploads just in case we had to
+// pause uploades because max items was exceeded
+//
+// call with the lock held
+func (wb *writeBack) _kickUploader() {
+	select {
+	case wb.kick <- struct{}{}:
+	default:
+	}
+}
+
+// upload the item - called as a goroutine
+func (wb *writeBack) upload(ctx context.Context, wbItem *writeBackItem) {
+	wb.mu.Lock()
+	defer wb.mu.Unlock()
+	item := wbItem.item
+	wbItem.tries++
+
+	wb.mu.Unlock()
+	err := item.store(ctx, wbItem.storeFn)
+	wb.mu.Lock()
+
+	wbItem.cancel() // cancel context to release resources since store done
+	if wbItem.uploading {
+		wbItem.uploading = false
+		wb.uploads--
+	}
+
+	if err != nil {
+		if wbItem.tries < maxUploadAttempts {
+			fs.Errorf(item.getName(), "vfs cache: failed to upload, will retry in %v: %v", wb.opt.WriteBack, err)
+			// push the item back on the queue for retry
+			wb._pushItem(wbItem)
+			wb.items._update(wbItem, time.Now().Add(wbItem.delay))
+			wbItem.delay *= 2
+		} else {
+			fs.Errorf(item.getName(), "vfs cache: failed to upload, will retry in %v: %v", wb.opt.WriteBack, err)
+		}
+	} else {
+		// show that we are done with the item
+		wb._delItem(wbItem)
+	}
+	wb._kickUploader()
+}
+
+// cancel the upload
+//
+// call with lock held
+func (wb *writeBack) _cancelUpload(wbItem *writeBackItem) {
+	if !wbItem.uploading {
+		return
+	}
+	fs.Debugf(wbItem.item.getName(), "vfs cache: canceling upload")
+	if wbItem.cancel != nil {
+		// Cancel the upload - this may or may not be effective
+		// we don't wait for the completion
+		wbItem.cancel()
+	}
+	if wbItem.uploading {
+		wbItem.uploading = false
+		wb.uploads--
+	}
+	// uploading items are not on the heap so add them back
+	wb._pushItem(wbItem)
+}
+
+// this uploads as many items as possible
+func (wb *writeBack) processItems(ctx context.Context) {
+	wb.mu.Lock()
+	defer wb.mu.Unlock()
+
+	resetTimer := false
+	for wbItem := wb._peekItem(); wbItem != nil && time.Until(wbItem.expiry) <= 0; wbItem = wb._peekItem() {
+		// If reached transfer limit don't restart the timer
+		if wb.uploads >= fs.Config.Transfers {
+			fs.Debugf(wbItem.item.getName(), "vfs cache: delaying writeback as --transfers exceeded")
+			resetTimer = false
+			break
+		}
+		resetTimer = true
+		// Pop the item, mark as uploading and start the uploader
+		wbItem = wb._popItem()
+		wbItem.uploading = true
+		wb.uploads++
+		newCtx, cancel := context.WithCancel(ctx)
+		wbItem.cancel = cancel
+		go wb.upload(newCtx, wbItem)
+	}
+
+	if resetTimer {
+		wb._resetTimer()
+	}
+}
+
+// Looks for items which need writing back and write them back until
+// the context is cancelled
+func (wb *writeBack) uploader(ctx context.Context) {
+	for {
+		select {
+		case <-ctx.Done():
+			wb.timer.Stop()
+			return
+		case <-wb.timer.C:
+			wb.processItems(ctx)
+		case <-wb.kick:
+			wb.processItems(ctx)
+		}
+	}
+}

vfs/vfscommon/options.go

@@ -30,6 +30,7 @@ type Options struct {
 	CaseInsensitive   bool
 	WriteWait         time.Duration // time to wait for in-sequence write
 	ReadWait          time.Duration // time to wait for in-sequence read
+	WriteBack         time.Duration // time to wait before writing back dirty files
 }
 
 // DefaultOpt is the default values uses for Opt
@@ -54,4 +55,5 @@ var DefaultOpt = Options{
 	CaseInsensitive:   runtime.GOOS == "windows" || runtime.GOOS == "darwin", // default to true on Windows and Mac, false otherwise
 	WriteWait:         1000 * time.Millisecond,
 	ReadWait:          20 * time.Millisecond,
+	WriteBack:         5 * time.Second,
 }

vfs/vfsflags/vfsflags.go

@@ -35,5 +35,6 @@ func AddFlags(flagSet *pflag.FlagSet) {
 	flags.BoolVarP(flagSet, &Opt.CaseInsensitive, "vfs-case-insensitive", "", Opt.CaseInsensitive, "If a file name not found, find a case insensitive match.")
 	flags.DurationVarP(flagSet, &Opt.WriteWait, "vfs-write-wait", "", Opt.WriteWait, "Time to wait for in-sequence write before giving error.")
 	flags.DurationVarP(flagSet, &Opt.ReadWait, "vfs-read-wait", "", Opt.ReadWait, "Time to wait for in-sequence read before seeking.")
+	flags.DurationVarP(flagSet, &Opt.WriteBack, "vfs-writeback", "", Opt.ReadWait, "Time to writeback files after last use when using cache.")
 	platformFlags(flagSet)
 }

vfs/vfstest/fs.go

@@ -46,17 +46,25 @@ var (
 func RunTests(t *testing.T, useVFS bool, fn MountFn) {
 	mountFn = fn
 	flag.Parse()
-	cacheModes := []vfscommon.CacheMode{
+	tests := []struct {
-		vfscommon.CacheModeOff,
+		cacheMode vfscommon.CacheMode
-		vfscommon.CacheModeMinimal,
+		writeBack time.Duration
-		vfscommon.CacheModeWrites,
+	}{
-		vfscommon.CacheModeFull,
+		{cacheMode: vfscommon.CacheModeOff},
+		{cacheMode: vfscommon.CacheModeMinimal},
+		{cacheMode: vfscommon.CacheModeWrites},
+		{cacheMode: vfscommon.CacheModeFull},
+		{cacheMode: vfscommon.CacheModeFull, writeBack: 100 * time.Millisecond},
 	}
 	run = newRun(useVFS)
-	for _, cacheMode := range cacheModes {
+	for _, test := range tests {
-		run.cacheMode(cacheMode)
+		run.cacheMode(test.cacheMode, test.writeBack)
-		log.Printf("Starting test run with cache mode %v", cacheMode)
+		what := fmt.Sprintf("CacheMode=%v", test.cacheMode)
-		ok := t.Run(fmt.Sprintf("CacheMode=%v", cacheMode), func(t *testing.T) {
+		if test.writeBack > 0 {
+			what += fmt.Sprintf(",WriteBack=%v", test.writeBack)
+		}
+		log.Printf("Starting test run with %s", what)
+		ok := t.Run(what, func(t *testing.T) {
 			t.Run("TestTouchAndDelete", TestTouchAndDelete)
 			t.Run("TestRenameOpenHandle", TestRenameOpenHandle)
 			t.Run("TestDirLs", TestDirLs)
@@ -84,7 +92,7 @@ func RunTests(t *testing.T, useVFS bool, fn MountFn) {
 			t.Run("TestWriteFileDup", TestWriteFileDup)
 			t.Run("TestWriteFileAppend", TestWriteFileAppend)
 		})
-		log.Printf("Finished test run with cache mode %v (ok=%v)", cacheMode, ok)
+		log.Printf("Finished test run with %s (ok=%v)", what, ok)
 		if !ok {
 			break
 		}
@@ -218,8 +226,8 @@ func (r *Run) umount() {
 	}
 }
 
-// cacheMode flushes the VFS and changes the CacheMode
+// cacheMode flushes the VFS and changes the CacheMode and the writeBack time
-func (r *Run) cacheMode(cacheMode vfscommon.CacheMode) {
+func (r *Run) cacheMode(cacheMode vfscommon.CacheMode, writeBack time.Duration) {
 	if r.skip {
 		log.Printf("FUSE not found so skipping cacheMode")
 		return
@@ -239,6 +247,7 @@ func (r *Run) cacheMode(cacheMode vfscommon.CacheMode) {
 	}
 	// Reset the cache mode
 	r.vfs.SetCacheMode(cacheMode)
+	r.vfs.Opt.WriteBack = writeBack
 	// Flush the directory cache
 	r.vfs.FlushDirCache()
 

vfs/write_test.go

@@ -17,21 +17,20 @@ import (
 )
 
 // Open a file for write
-func writeHandleCreate(t *testing.T, r *fstest.Run) (*VFS, *WriteFileHandle) {
+func writeHandleCreate(t *testing.T) (r *fstest.Run, vfs *VFS, fh *WriteFileHandle, cleanup func()) {
-	vfs := New(r.Fremote, nil)
+	r, vfs, cleanup = newTestVFS(t)
 
 	h, err := vfs.OpenFile("file1", os.O_WRONLY|os.O_CREATE, 0777)
 	require.NoError(t, err)
 	fh, ok := h.(*WriteFileHandle)
 	require.True(t, ok)
 
-	return vfs, fh
+	return r, vfs, fh, cleanup
 }
 
 func TestWriteFileHandleMethods(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, fh, cleanup := writeHandleCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, fh := writeHandleCreate(t, r)
 
 	// String
 	assert.Equal(t, "file1 (w)", fh.String())
@@ -133,9 +132,8 @@ func TestWriteFileHandleMethods(t *testing.T) {
 }
 
 func TestWriteFileHandleWriteAt(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, fh, cleanup := writeHandleCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, fh := writeHandleCreate(t, r)
 
 	// Preconditions
 	assert.Equal(t, int64(0), fh.offset)
@@ -179,9 +177,8 @@ func TestWriteFileHandleWriteAt(t *testing.T) {
 }
 
 func TestWriteFileHandleFlush(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, vfs, fh, cleanup := writeHandleCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, fh := writeHandleCreate(t, r)
 
 	// Check Flush already creates file for unwritten handles, without closing it
 	err := fh.Flush()
@@ -213,9 +210,8 @@ func TestWriteFileHandleFlush(t *testing.T) {
 }
 
 func TestWriteFileHandleRelease(t *testing.T) {
-	r := fstest.NewRun(t)
+	_, _, fh, cleanup := writeHandleCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	_, fh := writeHandleCreate(t, r)
 
 	// Check Release closes file
 	err := fh.Release()
@@ -262,12 +258,12 @@ func canSetModTime(t *testing.T, r *fstest.Run) bool {
 
 // tests mod time on open files
 func TestWriteFileModTimeWithOpenWriters(t *testing.T) {
-	r := fstest.NewRun(t)
+	r, vfs, fh, cleanup := writeHandleCreate(t)
-	defer r.Finalise()
+	defer cleanup()
+
 	if !canSetModTime(t, r) {
-		return
+		t.Skip("can't set mod time")
 	}
-	vfs, fh := writeHandleCreate(t, r)
 
 	mtime := time.Date(2012, time.November, 18, 17, 32, 31, 0, time.UTC)
 
@@ -290,9 +286,8 @@ func TestWriteFileModTimeWithOpenWriters(t *testing.T) {
 }
 
 func testFileReadAt(t *testing.T, n int) {
-	r := fstest.NewRun(t)
+	_, vfs, fh, cleanup := writeHandleCreate(t)
-	defer r.Finalise()
+	defer cleanup()
-	vfs, fh := writeHandleCreate(t, r)
 
 	contents := []byte(random.String(n))
 	if n != 0 {