backup: By default, do not save the access time

This can be re-enabled with `--with-atime`.

cmd/restic/cmd_backup.go

@@ -65,6 +65,7 @@ type BackupOptions struct {
 	Hostname         string
 	FilesFrom        string
 	TimeStamp        string
+	WithAtime        bool
 }
 
 var backupOptions BackupOptions
@@ -86,6 +87,7 @@ func init() {
 	f.StringVar(&backupOptions.Hostname, "hostname", "", "set the `hostname` for the snapshot manually. To prevent an expensive rescan use the \"parent\" flag")
 	f.StringVar(&backupOptions.FilesFrom, "files-from", "", "read the files to backup from file (can be combined with file args)")
 	f.StringVar(&backupOptions.TimeStamp, "time", "", "time of the backup (ex. '2012-11-01 22:08:41') (default: now)")
+	f.BoolVar(&backupOptions.WithAtime, "with-atime", false, "store the atime for all files and directories")
 }
 
 func newScanProgress(gopts GlobalOptions) *restic.Progress {
@@ -452,6 +454,7 @@ func runBackup(opts BackupOptions, gopts GlobalOptions, args []string) error {
 	arch := archiver.New(repo)
 	arch.Excludes = opts.Excludes
 	arch.SelectFilter = selectFilter
+	arch.WithAccessTime = opts.WithAtime
 
 	arch.Warn = func(dir string, fi os.FileInfo, err error) {
 		// TODO: make ignoring errors configurable

internal/archiver/archiver.go

@@ -45,6 +45,8 @@ type Archiver struct {
 	Warn         func(dir string, fi os.FileInfo, err error)
 	SelectFilter pipe.SelectFunc
 	Excludes     []string
+
+	WithAccessTime bool
 }
 
 // New returns a new archiver.
@@ -129,6 +131,10 @@ func (arch *Archiver) SaveTreeJSON(ctx context.Context, tree *restic.Tree) (rest
 }
 
 func (arch *Archiver) reloadFileIfChanged(node *restic.Node, file fs.File) (*restic.Node, error) {
+	if !arch.WithAccessTime {
+		node.AccessTime = node.ModTime
+	}
+
 	fi, err := file.Stat()
 	if err != nil {
 		return nil, errors.Wrap(err, "restic.Stat")
@@ -146,6 +152,10 @@ func (arch *Archiver) reloadFileIfChanged(node *restic.Node, file fs.File) (*res
 		arch.Warn(node.Path, fi, err)
 	}
 
+	if !arch.WithAccessTime {
+		node.AccessTime = node.ModTime
+	}
+
 	return node, nil
 }
 
@@ -282,6 +292,10 @@ func (arch *Archiver) fileWorker(ctx context.Context, wg *sync.WaitGroup, p *res
 				arch.Warn(e.Fullpath(), e.Info(), err)
 			}
 
+			if !arch.WithAccessTime {
+				node.AccessTime = node.ModTime
+			}
+
 			// try to use old node, if present
 			if e.Node != nil {
 				debug.Log("   %v use old data", e.Path())
@@ -410,6 +424,10 @@ func (arch *Archiver) dirWorker(ctx context.Context, wg *sync.WaitGroup, p *rest
 					arch.Warn(dir.Path(), dir.Info(), err)
 				}
 				node = n
+
+				if !arch.WithAccessTime {
+					node.AccessTime = node.ModTime
+				}
 			}
 
 			if err := dir.Error(); err != nil {