Look for Fs in the cache rather than calling NewFs directly

This will save operations when rclone is used in remote control mode
or with the same remote multiple times in the command line.

backend/cache/cache.go

@@ -20,6 +20,7 @@ import (
 
 	"github.com/ncw/rclone/backend/crypt"
 	"github.com/ncw/rclone/fs"
+	"github.com/ncw/rclone/fs/cache"
 	"github.com/ncw/rclone/fs/config"
 	"github.com/ncw/rclone/fs/config/configmap"
 	"github.com/ncw/rclone/fs/config/configstruct"
@@ -481,7 +482,7 @@ func NewFs(name, rootPath string, m configmap.Mapper) (fs.Fs, error) {
 			return nil, errors.Wrapf(err, "failed to create cache directory %v", f.opt.TempWritePath)
 		}
 		f.opt.TempWritePath = filepath.ToSlash(f.opt.TempWritePath)
-		f.tempFs, err = fs.NewFs(f.opt.TempWritePath)
+		f.tempFs, err = cache.Get(f.opt.TempWritePath)
 		if err != nil {
 			return nil, errors.Wrapf(err, "failed to create temp fs: %v", err)
 		}

backend/union/union.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/ncw/rclone/fs"
+	"github.com/ncw/rclone/fs/cache"
 	"github.com/ncw/rclone/fs/config/configmap"
 	"github.com/ncw/rclone/fs/config/configstruct"
 	"github.com/ncw/rclone/fs/hash"
@@ -342,7 +343,7 @@ func NewFs(name, root string, m configmap.Mapper) (fs.Fs, error) {
 		if configName != "local" {
 			rootString = configName + ":" + rootString
 		}
-		myFs, err := fs.NewFs(rootString)
+		myFs, err := cache.Get(rootString)
 		if err != nil {
 			if err == fs.ErrorIsFile {
 				return myFs, err

cmd/cmd.go

@@ -22,6 +22,7 @@ import (
 
 	"github.com/ncw/rclone/fs"
 	"github.com/ncw/rclone/fs/accounting"
+	"github.com/ncw/rclone/fs/cache"
 	"github.com/ncw/rclone/fs/config/configflags"
 	"github.com/ncw/rclone/fs/config/flags"
 	"github.com/ncw/rclone/fs/filter"
@@ -83,7 +84,7 @@ func NewFsFile(remote string) (fs.Fs, string) {
 		fs.CountError(err)
 		log.Fatalf("Failed to create file system for %q: %v", remote, err)
 	}
-	f, err := fs.NewFs(remote)
+	f, err := cache.Get(remote)
 	switch err {
 	case fs.ErrorIsFile:
 		return f, path.Base(fsPath)
@@ -131,7 +132,7 @@ func NewFsSrc(args []string) fs.Fs {
 //
 // This must point to a directory
 func newFsDir(remote string) fs.Fs {
-	f, err := fs.NewFs(remote)
+	f, err := cache.Get(remote)
 	if err != nil {
 		fs.CountError(err)
 		log.Fatalf("Failed to create file system for %q: %v", remote, err)
@@ -180,7 +181,7 @@ func NewFsSrcDstFiles(args []string) (fsrc fs.Fs, srcFileName string, fdst fs.Fs
 			log.Fatalf("%q is a directory", args[1])
 		}
 	}
-	fdst, err := fs.NewFs(dstRemote)
+	fdst, err := cache.Get(dstRemote)
 	switch err {
 	case fs.ErrorIsFile:
 		fs.CountError(err)

fs/sync/sync.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/ncw/rclone/fs"
 	"github.com/ncw/rclone/fs/accounting"
+	"github.com/ncw/rclone/fs/cache"
 	"github.com/ncw/rclone/fs/filter"
 	"github.com/ncw/rclone/fs/fserrors"
 	"github.com/ncw/rclone/fs/hash"
@@ -123,7 +124,7 @@ func newSyncCopyMove(fdst, fsrc fs.Fs, deleteMode fs.DeleteMode, DoMove bool, de
 	// Make Fs for --backup-dir if required
 	if fs.Config.BackupDir != "" {
 		var err error
-		s.backupDir, err = fs.NewFs(fs.Config.BackupDir)
+		s.backupDir, err = cache.Get(fs.Config.BackupDir)
 		if err != nil {
 			return nil, fserrors.FatalError(errors.Errorf("Failed to make fs for --backup-dir %q: %v", fs.Config.BackupDir, err))
 		}

vfs/cache.go

@@ -16,6 +16,7 @@ import (
 
 	"github.com/djherbis/times"
 	"github.com/ncw/rclone/fs"
+	fscache "github.com/ncw/rclone/fs/cache"
 	"github.com/ncw/rclone/fs/config"
 	"github.com/pkg/errors"
 )
@@ -100,7 +101,7 @@ func newCache(ctx context.Context, f fs.Fs, opt *Options) (*cache, error) {
 	root := filepath.Join(config.CacheDir, "vfs", f.Name(), fRoot)
 	fs.Debugf(nil, "vfs cache root is %q", root)
 
-	f, err := fs.NewFs(root)
+	f, err := fscache.Get(root)
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to create cache remote")
 	}