From 641390103df726f2023c93377fec35379a72a485 Mon Sep 17 00:00:00 2001
From: Michael Eischer <michael.eischer@fau.de>
Date: Sun, 3 Nov 2024 16:01:59 +0100
Subject: [PATCH 1/3] fs: inline ExtendedStat

---
 cmd/restic/cmd_backup_integration_test.go  |  2 +-
 internal/archiver/archiver.go              | 15 +++---
 internal/archiver/archiver_test.go         | 22 ++++-----
 internal/archiver/archiver_unix_test.go    | 22 ++++-----
 internal/archiver/archiver_windows_test.go | 22 +++++----
 internal/archiver/exclude.go               | 42 ++++++----------
 internal/archiver/exclude_test.go          |  2 +-
 internal/archiver/scanner.go               |  5 +-
 internal/archiver/scanner_test.go          |  2 +-
 internal/fs/deviceid_unix.go               | 31 ------------
 internal/fs/deviceid_windows.go            | 16 -------
 internal/fs/fs_local.go                    | 36 +++++++-------
 internal/fs/fs_local_test.go               |  4 +-
 internal/fs/fs_local_vss.go                |  3 +-
 internal/fs/fs_reader.go                   | 56 +++++++++-------------
 internal/fs/fs_reader_test.go              |  6 +--
 internal/fs/interface.go                   |  7 +--
 internal/fs/node.go                        | 15 +++---
 internal/fs/stat.go                        |  2 +-
 internal/fs/stat_bsd.go                    |  6 +--
 internal/fs/stat_unix.go                   |  6 +--
 internal/fs/stat_windows.go                |  4 +-
 22 files changed, 121 insertions(+), 205 deletions(-)
 delete mode 100644 internal/fs/deviceid_unix.go
 delete mode 100644 internal/fs/deviceid_windows.go

diff --git a/cmd/restic/cmd_backup_integration_test.go b/cmd/restic/cmd_backup_integration_test.go
index 4278f07ca..06d71e345 100644
--- a/cmd/restic/cmd_backup_integration_test.go
+++ b/cmd/restic/cmd_backup_integration_test.go
@@ -132,7 +132,7 @@ type vssDeleteOriginalFS struct {
 	hasRemoved bool
 }
 
-func (f *vssDeleteOriginalFS) Lstat(name string) (os.FileInfo, error) {
+func (f *vssDeleteOriginalFS) Lstat(name string) (*fs.ExtendedFileInfo, error) {
 	if !f.hasRemoved {
 		// call Lstat to trigger snapshot creation
 		_, _ = f.FS.Lstat(name)
diff --git a/internal/archiver/archiver.go b/internal/archiver/archiver.go
index 5d4648e03..f730fe0a5 100644
--- a/internal/archiver/archiver.go
+++ b/internal/archiver/archiver.go
@@ -25,7 +25,7 @@ type SelectByNameFunc func(item string) bool
 
 // SelectFunc returns true for all items that should be included (files and
 // dirs). If false is returned, files are ignored and dirs are not even walked.
-type SelectFunc func(item string, fi os.FileInfo, fs fs.FS) bool
+type SelectFunc func(item string, fi *fs.ExtendedFileInfo, fs fs.FS) bool
 
 // ErrorFunc is called when an error during archiving occurs. When nil is
 // returned, the archiver continues, otherwise it aborts and passes the error
@@ -189,7 +189,7 @@ func New(repo archiverRepo, filesystem fs.FS, opts Options) *Archiver {
 	arch := &Archiver{
 		Repo:         repo,
 		SelectByName: func(_ string) bool { return true },
-		Select:       func(_ string, _ os.FileInfo, _ fs.FS) bool { return true },
+		Select:       func(_ string, _ *fs.ExtendedFileInfo, _ fs.FS) bool { return true },
 		FS:           filesystem,
 		Options:      opts.ApplyDefaults(),
 
@@ -618,27 +618,26 @@ func (arch *Archiver) save(ctx context.Context, snPath, target string, previous
 // fileChanged tries to detect whether a file's content has changed compared
 // to the contents of node, which describes the same path in the parent backup.
 // It should only be run for regular files.
-func fileChanged(fs fs.FS, fi os.FileInfo, node *restic.Node, ignoreFlags uint) bool {
+func fileChanged(fs fs.FS, fi *fs.ExtendedFileInfo, node *restic.Node, ignoreFlags uint) bool {
 	switch {
 	case node == nil:
 		return true
 	case node.Type != restic.NodeTypeFile:
 		// We're only called for regular files, so this is a type change.
 		return true
-	case uint64(fi.Size()) != node.Size:
+	case uint64(fi.Size) != node.Size:
 		return true
-	case !fi.ModTime().Equal(node.ModTime):
+	case !fi.ModTime.Equal(node.ModTime):
 		return true
 	}
 
 	checkCtime := ignoreFlags&ChangeIgnoreCtime == 0
 	checkInode := ignoreFlags&ChangeIgnoreInode == 0
 
-	extFI := fs.ExtendedStat(fi)
 	switch {
-	case checkCtime && !extFI.ChangeTime.Equal(node.ChangeTime):
+	case checkCtime && !fi.ChangeTime.Equal(node.ChangeTime):
 		return true
-	case checkInode && node.Inode != extFI.Inode:
+	case checkInode && node.Inode != fi.Inode:
 		return true
 	}
 
diff --git a/internal/archiver/archiver_test.go b/internal/archiver/archiver_test.go
index f57c4894b..038afd11d 100644
--- a/internal/archiver/archiver_test.go
+++ b/internal/archiver/archiver_test.go
@@ -516,13 +516,13 @@ func chmodTwice(t testing.TB, name string) {
 	rtest.OK(t, err)
 }
 
-func lstat(t testing.TB, name string) os.FileInfo {
+func lstat(t testing.TB, name string) *fs.ExtendedFileInfo {
 	fi, err := os.Lstat(name)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	return fi
+	return fs.ExtendedStat(fi)
 }
 
 func setTimestamp(t testing.TB, filename string, atime, mtime time.Time) {
@@ -660,7 +660,7 @@ func TestFileChanged(t *testing.T) {
 				rename(t, filename, tempname)
 				save(t, filename, defaultContent)
 				remove(t, tempname)
-				setTimestamp(t, filename, fi.ModTime(), fi.ModTime())
+				setTimestamp(t, filename, fi.ModTime, fi.ModTime)
 			},
 			ChangeIgnore: ChangeIgnoreCtime | ChangeIgnoreInode,
 			SameFile:     true,
@@ -1520,7 +1520,7 @@ func TestArchiverSnapshotSelect(t *testing.T) {
 				},
 				"other": TestFile{Content: "another file"},
 			},
-			selFn: func(item string, fi os.FileInfo, _ fs.FS) bool {
+			selFn: func(item string, fi *fs.ExtendedFileInfo, _ fs.FS) bool {
 				return true
 			},
 		},
@@ -1537,7 +1537,7 @@ func TestArchiverSnapshotSelect(t *testing.T) {
 				},
 				"other": TestFile{Content: "another file"},
 			},
-			selFn: func(item string, fi os.FileInfo, _ fs.FS) bool {
+			selFn: func(item string, fi *fs.ExtendedFileInfo, _ fs.FS) bool {
 				return false
 			},
 			err: "snapshot is empty",
@@ -1564,7 +1564,7 @@ func TestArchiverSnapshotSelect(t *testing.T) {
 				},
 				"other": TestFile{Content: "another file"},
 			},
-			selFn: func(item string, fi os.FileInfo, _ fs.FS) bool {
+			selFn: func(item string, fi *fs.ExtendedFileInfo, _ fs.FS) bool {
 				return filepath.Ext(item) != ".txt"
 			},
 		},
@@ -1588,7 +1588,7 @@ func TestArchiverSnapshotSelect(t *testing.T) {
 				},
 				"other": TestFile{Content: "another file"},
 			},
-			selFn: func(item string, fi os.FileInfo, fs fs.FS) bool {
+			selFn: func(item string, fi *fs.ExtendedFileInfo, fs fs.FS) bool {
 				return fs.Base(item) != "subdir"
 			},
 		},
@@ -1597,7 +1597,7 @@ func TestArchiverSnapshotSelect(t *testing.T) {
 			src: TestDir{
 				"foo": TestFile{Content: "foo"},
 			},
-			selFn: func(item string, fi os.FileInfo, fs fs.FS) bool {
+			selFn: func(item string, fi *fs.ExtendedFileInfo, fs fs.FS) bool {
 				return fs.IsAbs(item)
 			},
 		},
@@ -2202,7 +2202,7 @@ func snapshot(t testing.TB, repo archiverRepo, fs fs.FS, parent *restic.Snapshot
 
 type overrideFS struct {
 	fs.FS
-	overrideFI    os.FileInfo
+	overrideFI    *fs.ExtendedFileInfo
 	resetFIOnRead bool
 	overrideNode  *restic.Node
 	overrideErr   error
@@ -2225,7 +2225,7 @@ type overrideFile struct {
 	ofs *overrideFS
 }
 
-func (f overrideFile) Stat() (os.FileInfo, error) {
+func (f overrideFile) Stat() (*fs.ExtendedFileInfo, error) {
 	if f.ofs.overrideFI == nil {
 		return f.File.Stat()
 	}
@@ -2497,7 +2497,7 @@ type missingFile struct {
 	fs.File
 }
 
-func (f *missingFile) Stat() (os.FileInfo, error) {
+func (f *missingFile) Stat() (*fs.ExtendedFileInfo, error) {
 	return nil, os.ErrNotExist
 }
 
diff --git a/internal/archiver/archiver_unix_test.go b/internal/archiver/archiver_unix_test.go
index deeab6459..d3e87b57e 100644
--- a/internal/archiver/archiver_unix_test.go
+++ b/internal/archiver/archiver_unix_test.go
@@ -29,7 +29,7 @@ func (fi wrappedFileInfo) Mode() os.FileMode {
 }
 
 // wrapFileInfo returns a new os.FileInfo with the mode, owner, and group fields changed.
-func wrapFileInfo(fi os.FileInfo) os.FileInfo {
+func wrapFileInfo(fi *fs.ExtendedFileInfo) *fs.ExtendedFileInfo {
 	// get the underlying stat_t and modify the values
 	stat := fi.Sys().(*syscall.Stat_t)
 	stat.Mode = mockFileInfoMode
@@ -37,22 +37,22 @@ func wrapFileInfo(fi os.FileInfo) os.FileInfo {
 	stat.Gid = mockFileInfoGID
 
 	// wrap the os.FileInfo so we can return a modified stat_t
-	res := wrappedFileInfo{
-		FileInfo: fi,
+	return fs.ExtendedStat(wrappedFileInfo{
+		FileInfo: fi.FileInfo,
 		sys:      stat,
 		mode:     mockFileInfoMode,
-	}
-
-	return res
+	})
 }
 
 // wrapIrregularFileInfo returns a new os.FileInfo with the mode changed to irregular file
-func wrapIrregularFileInfo(fi os.FileInfo) os.FileInfo {
+func wrapIrregularFileInfo(fi *fs.ExtendedFileInfo) *fs.ExtendedFileInfo {
 	// wrap the os.FileInfo so we can return a modified stat_t
-	return wrappedFileInfo{
-		FileInfo: fi,
-		sys:      fi.Sys().(*syscall.Stat_t),
-		mode:     (fi.Mode() &^ os.ModeType) | os.ModeIrregular,
+	return &fs.ExtendedFileInfo{
+		FileInfo: wrappedFileInfo{
+			FileInfo: fi.FileInfo,
+			sys:      fi.Sys(),
+			mode:     (fi.Mode() &^ os.ModeType) | os.ModeIrregular,
+		},
 	}
 }
 
diff --git a/internal/archiver/archiver_windows_test.go b/internal/archiver/archiver_windows_test.go
index ac8a67f2b..2e873c1b7 100644
--- a/internal/archiver/archiver_windows_test.go
+++ b/internal/archiver/archiver_windows_test.go
@@ -5,6 +5,8 @@ package archiver
 
 import (
 	"os"
+
+	"github.com/restic/restic/internal/fs"
 )
 
 type wrappedFileInfo struct {
@@ -17,20 +19,20 @@ func (fi wrappedFileInfo) Mode() os.FileMode {
 }
 
 // wrapFileInfo returns a new os.FileInfo with the mode, owner, and group fields changed.
-func wrapFileInfo(fi os.FileInfo) os.FileInfo {
+func wrapFileInfo(fi *fs.ExtendedFileInfo) *fs.ExtendedFileInfo {
 	// wrap the os.FileInfo and return the modified mode, uid and gid are ignored on Windows
-	res := wrappedFileInfo{
-		FileInfo: fi,
+	return fs.ExtendedStat(wrappedFileInfo{
+		FileInfo: fi.FileInfo,
 		mode:     mockFileInfoMode,
-	}
-
-	return res
+	})
 }
 
 // wrapIrregularFileInfo returns a new os.FileInfo with the mode changed to irregular file
-func wrapIrregularFileInfo(fi os.FileInfo) os.FileInfo {
-	return wrappedFileInfo{
-		FileInfo: fi,
-		mode:     (fi.Mode() &^ os.ModeType) | os.ModeIrregular,
+func wrapIrregularFileInfo(fi *fs.ExtendedFileInfo) *fs.ExtendedFileInfo {
+	return &fs.ExtendedFileInfo{
+		FileInfo: wrappedFileInfo{
+			FileInfo: fi.FileInfo,
+			mode:     (fi.Mode() &^ os.ModeType) | os.ModeIrregular,
+		},
 	}
 }
diff --git a/internal/archiver/exclude.go b/internal/archiver/exclude.go
index 418517fd9..e1939d292 100644
--- a/internal/archiver/exclude.go
+++ b/internal/archiver/exclude.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"runtime"
 	"strings"
 	"sync"
 
@@ -21,7 +22,7 @@ type RejectByNameFunc func(path string) bool
 // RejectFunc is a function that takes a filename and os.FileInfo of a
 // file that would be included in the backup. The function returns true if it
 // should be excluded (rejected) from the backup.
-type RejectFunc func(path string, fi os.FileInfo, fs fs.FS) bool
+type RejectFunc func(path string, fi *fs.ExtendedFileInfo, fs fs.FS) bool
 
 func CombineRejectByNames(funcs []RejectByNameFunc) SelectByNameFunc {
 	return func(item string) bool {
@@ -35,7 +36,7 @@ func CombineRejectByNames(funcs []RejectByNameFunc) SelectByNameFunc {
 }
 
 func CombineRejects(funcs []RejectFunc) SelectFunc {
-	return func(item string, fi os.FileInfo, fs fs.FS) bool {
+	return func(item string, fi *fs.ExtendedFileInfo, fs fs.FS) bool {
 		for _, reject := range funcs {
 			if reject(item, fi, fs) {
 				return false
@@ -104,7 +105,7 @@ func RejectIfPresent(excludeFileSpec string, warnf func(msg string, args ...inte
 	}
 	debug.Log("using %q as exclusion tagfile", tf)
 	rc := newRejectionCache()
-	return func(filename string, _ os.FileInfo, fs fs.FS) bool {
+	return func(filename string, _ *fs.ExtendedFileInfo, fs fs.FS) bool {
 		return isExcludedByFile(filename, tf, tc, rc, fs, warnf)
 	}, nil
 }
@@ -186,6 +187,10 @@ type deviceMap map[string]uint64
 
 // newDeviceMap creates a new device map from the list of source paths.
 func newDeviceMap(allowedSourcePaths []string, fs fs.FS) (deviceMap, error) {
+	if runtime.GOOS == "windows" {
+		return nil, errors.New("Device IDs are not supported on Windows")
+	}
+
 	deviceMap := make(map[string]uint64)
 
 	for _, item := range allowedSourcePaths {
@@ -199,12 +204,7 @@ func newDeviceMap(allowedSourcePaths []string, fs fs.FS) (deviceMap, error) {
 			return nil, err
 		}
 
-		id, err := fs.DeviceID(fi)
-		if err != nil {
-			return nil, err
-		}
-
-		deviceMap[item] = id
+		deviceMap[item] = fi.DeviceID
 	}
 
 	if len(deviceMap) == 0 {
@@ -254,15 +254,8 @@ func RejectByDevice(samples []string, filesystem fs.FS) (RejectFunc, error) {
 	}
 	debug.Log("allowed devices: %v\n", deviceMap)
 
-	return func(item string, fi os.FileInfo, fs fs.FS) bool {
-		id, err := fs.DeviceID(fi)
-		if err != nil {
-			// This should never happen because gatherDevices() would have
-			// errored out earlier. If it still does that's a reason to panic.
-			panic(err)
-		}
-
-		allowed, err := deviceMap.IsAllowed(fs.Clean(item), id, fs)
+	return func(item string, fi *fs.ExtendedFileInfo, fs fs.FS) bool {
+		allowed, err := deviceMap.IsAllowed(fs.Clean(item), fi.DeviceID, fs)
 		if err != nil {
 			// this should not happen
 			panic(fmt.Sprintf("error checking device ID of %v: %v", item, err))
@@ -290,14 +283,7 @@ func RejectByDevice(samples []string, filesystem fs.FS) (RejectFunc, error) {
 			return true
 		}
 
-		parentDeviceID, err := fs.DeviceID(parentFI)
-		if err != nil {
-			debug.Log("item %v: getting device ID of parent directory: %v", item, err)
-			// if in doubt, reject
-			return true
-		}
-
-		parentAllowed, err := deviceMap.IsAllowed(parentDir, parentDeviceID, fs)
+		parentAllowed, err := deviceMap.IsAllowed(parentDir, parentFI.DeviceID, fs)
 		if err != nil {
 			debug.Log("item %v: error checking parent directory: %v", item, err)
 			// if in doubt, reject
@@ -315,13 +301,13 @@ func RejectByDevice(samples []string, filesystem fs.FS) (RejectFunc, error) {
 }
 
 func RejectBySize(maxSize int64) (RejectFunc, error) {
-	return func(item string, fi os.FileInfo, _ fs.FS) bool {
+	return func(item string, fi *fs.ExtendedFileInfo, _ fs.FS) bool {
 		// directory will be ignored
 		if fi.IsDir() {
 			return false
 		}
 
-		filesize := fi.Size()
+		filesize := fi.Size
 		if filesize > maxSize {
 			debug.Log("file %s is oversize: %d", item, filesize)
 			return true
diff --git a/internal/archiver/exclude_test.go b/internal/archiver/exclude_test.go
index 7eb24b08b..9bfa5d83f 100644
--- a/internal/archiver/exclude_test.go
+++ b/internal/archiver/exclude_test.go
@@ -193,7 +193,7 @@ func TestIsExcludedByFileSize(t *testing.T) {
 			return err
 		}
 
-		excluded := sizeExclude(p, fi, nil)
+		excluded := sizeExclude(p, fs.ExtendedStat(fi), nil)
 		// the log message helps debugging in case the test fails
 		t.Logf("%q: dir:%t; size:%d; excluded:%v", p, fi.IsDir(), fi.Size(), excluded)
 		m[p] = !excluded
diff --git a/internal/archiver/scanner.go b/internal/archiver/scanner.go
index debd09aa3..ebcca0df1 100644
--- a/internal/archiver/scanner.go
+++ b/internal/archiver/scanner.go
@@ -2,7 +2,6 @@ package archiver
 
 import (
 	"context"
-	"os"
 	"sort"
 
 	"github.com/restic/restic/internal/debug"
@@ -25,7 +24,7 @@ func NewScanner(filesystem fs.FS) *Scanner {
 	return &Scanner{
 		FS:           filesystem,
 		SelectByName: func(_ string) bool { return true },
-		Select:       func(_ string, _ os.FileInfo, _ fs.FS) bool { return true },
+		Select:       func(_ string, _ *fs.ExtendedFileInfo, _ fs.FS) bool { return true },
 		Error:        func(_ string, err error) error { return err },
 		Result:       func(_ string, _ ScanStats) {},
 	}
@@ -121,7 +120,7 @@ func (s *Scanner) scan(ctx context.Context, stats ScanStats, target string) (Sca
 	switch {
 	case fi.Mode().IsRegular():
 		stats.Files++
-		stats.Bytes += uint64(fi.Size())
+		stats.Bytes += uint64(fi.Size)
 	case fi.Mode().IsDir():
 		names, err := fs.Readdirnames(s.FS, target, fs.O_NOFOLLOW)
 		if err != nil {
diff --git a/internal/archiver/scanner_test.go b/internal/archiver/scanner_test.go
index e4e2c9f59..0504cb8bd 100644
--- a/internal/archiver/scanner_test.go
+++ b/internal/archiver/scanner_test.go
@@ -56,7 +56,7 @@ func TestScanner(t *testing.T) {
 					},
 				},
 			},
-			selFn: func(item string, fi os.FileInfo, fs fs.FS) bool {
+			selFn: func(item string, fi *fs.ExtendedFileInfo, fs fs.FS) bool {
 				if fi.IsDir() {
 					return true
 				}
diff --git a/internal/fs/deviceid_unix.go b/internal/fs/deviceid_unix.go
deleted file mode 100644
index 4d5593335..000000000
--- a/internal/fs/deviceid_unix.go
+++ /dev/null
@@ -1,31 +0,0 @@
-//go:build !windows
-// +build !windows
-
-package fs
-
-import (
-	"os"
-	"syscall"
-
-	"github.com/restic/restic/internal/errors"
-)
-
-// deviceID extracts the device ID from an os.FileInfo object by casting it
-// to syscall.Stat_t
-func deviceID(fi os.FileInfo) (deviceID uint64, err error) {
-	if fi == nil {
-		return 0, errors.New("unable to determine device: fi is nil")
-	}
-
-	if fi.Sys() == nil {
-		return 0, errors.New("unable to determine device: fi.Sys() is nil")
-	}
-
-	if st, ok := fi.Sys().(*syscall.Stat_t); ok {
-		// st.Dev is uint32 on Darwin and uint64 on Linux. Just cast
-		// everything to uint64.
-		return uint64(st.Dev), nil
-	}
-
-	return 0, errors.New("Could not cast to syscall.Stat_t")
-}
diff --git a/internal/fs/deviceid_windows.go b/internal/fs/deviceid_windows.go
deleted file mode 100644
index bfb22dc9a..000000000
--- a/internal/fs/deviceid_windows.go
+++ /dev/null
@@ -1,16 +0,0 @@
-//go:build windows
-// +build windows
-
-package fs
-
-import (
-	"os"
-
-	"github.com/restic/restic/internal/errors"
-)
-
-// deviceID extracts the device ID from an os.FileInfo object by casting it
-// to syscall.Stat_t
-func deviceID(_ os.FileInfo) (deviceID uint64, err error) {
-	return 0, errors.New("Device IDs are not supported on Windows")
-}
diff --git a/internal/fs/fs_local.go b/internal/fs/fs_local.go
index 5e6c72d0a..fc6c69cf2 100644
--- a/internal/fs/fs_local.go
+++ b/internal/fs/fs_local.go
@@ -36,19 +36,12 @@ func (fs Local) OpenFile(name string, flag int, metadataOnly bool) (File, error)
 // If the file is a symbolic link, the returned FileInfo
 // describes the symbolic link.  Lstat makes no attempt to follow the link.
 // If there is an error, it will be of type *PathError.
-func (fs Local) Lstat(name string) (os.FileInfo, error) {
-	return os.Lstat(fixpath(name))
-}
-
-// DeviceID extracts the DeviceID from the given FileInfo. If the fs does
-// not support a DeviceID, it returns an error instead
-func (fs Local) DeviceID(fi os.FileInfo) (id uint64, err error) {
-	return deviceID(fi)
-}
-
-// ExtendedStat converts the give FileInfo into ExtendedFileInfo.
-func (fs Local) ExtendedStat(fi os.FileInfo) ExtendedFileInfo {
-	return ExtendedStat(fi)
+func (fs Local) Lstat(name string) (*ExtendedFileInfo, error) {
+	fi, err := os.Lstat(fixpath(name))
+	if err != nil {
+		return nil, err
+	}
+	return extendedStat(fi), nil
 }
 
 // Join joins any number of path elements into a single path, adding a
@@ -96,7 +89,7 @@ type localFile struct {
 	name string
 	flag int
 	f    *os.File
-	fi   os.FileInfo
+	fi   *ExtendedFileInfo
 }
 
 // See the File interface for a description of each method
@@ -137,18 +130,23 @@ func (f *localFile) cacheFI() error {
 	if f.fi != nil {
 		return nil
 	}
+	var fi os.FileInfo
 	var err error
 	if f.f != nil {
-		f.fi, err = f.f.Stat()
+		fi, err = f.f.Stat()
 	} else if f.flag&O_NOFOLLOW != 0 {
-		f.fi, err = os.Lstat(f.name)
+		fi, err = os.Lstat(f.name)
 	} else {
-		f.fi, err = os.Stat(f.name)
+		fi, err = os.Stat(f.name)
 	}
-	return err
+	if err != nil {
+		return err
+	}
+	f.fi = extendedStat(fi)
+	return nil
 }
 
-func (f *localFile) Stat() (os.FileInfo, error) {
+func (f *localFile) Stat() (*ExtendedFileInfo, error) {
 	err := f.cacheFI()
 	// the call to cacheFI MUST happen before reading from f.fi
 	return f.fi, err
diff --git a/internal/fs/fs_local_test.go b/internal/fs/fs_local_test.go
index b1e85de0a..74cc8b48c 100644
--- a/internal/fs/fs_local_test.go
+++ b/internal/fs/fs_local_test.go
@@ -84,13 +84,13 @@ func checkMetadata(t *testing.T, f File, path string, follow bool, nodeType rest
 		fi2, err = os.Lstat(path)
 	}
 	rtest.OK(t, err)
-	assertFIEqual(t, fi2, fi)
+	assertFIEqual(t, fi2, fi.FileInfo)
 
 	node, err := f.ToNode(false)
 	rtest.OK(t, err)
 
 	// ModTime is likely unique per file, thus it provides a good indication that it is from the correct file
-	rtest.Equals(t, fi.ModTime(), node.ModTime, "node ModTime")
+	rtest.Equals(t, fi.ModTime, node.ModTime, "node ModTime")
 	rtest.Equals(t, nodeType, node.Type, "node Type")
 }
 
diff --git a/internal/fs/fs_local_vss.go b/internal/fs/fs_local_vss.go
index fe82b85e1..dfee31779 100644
--- a/internal/fs/fs_local_vss.go
+++ b/internal/fs/fs_local_vss.go
@@ -1,7 +1,6 @@
 package fs
 
 import (
-	"os"
 	"path/filepath"
 	"runtime"
 	"strings"
@@ -131,7 +130,7 @@ func (fs *LocalVss) OpenFile(name string, flag int, metadataOnly bool) (File, er
 }
 
 // Lstat wraps the Lstat method of the underlying file system.
-func (fs *LocalVss) Lstat(name string) (os.FileInfo, error) {
+func (fs *LocalVss) Lstat(name string) (*ExtendedFileInfo, error) {
 	return fs.FS.Lstat(fs.snapshotPath(name))
 }
 
diff --git a/internal/fs/fs_reader.go b/internal/fs/fs_reader.go
index 8728b274c..8b7668730 100644
--- a/internal/fs/fs_reader.go
+++ b/internal/fs/fs_reader.go
@@ -5,6 +5,7 @@ import (
 	"io"
 	"os"
 	"path"
+	"slices"
 	"sync"
 	"syscall"
 	"time"
@@ -40,12 +41,14 @@ func (fs *Reader) VolumeName(_ string) string {
 	return ""
 }
 
-func (fs *Reader) fi() os.FileInfo {
-	return fakeFileInfo{
-		name:    fs.Name,
-		size:    fs.Size,
-		mode:    fs.Mode,
-		modtime: fs.ModTime,
+func (fs *Reader) fi() *ExtendedFileInfo {
+	return &ExtendedFileInfo{
+		FileInfo: fakeFileInfo{
+			name:    fs.Name,
+			size:    fs.Size,
+			mode:    fs.Mode,
+			modtime: fs.ModTime,
+		},
 	}
 }
 
@@ -68,7 +71,7 @@ func (fs *Reader) OpenFile(name string, flag int, _ bool) (f File, err error) {
 		return f, nil
 	case "/", ".":
 		f = fakeDir{
-			entries: []os.FileInfo{fs.fi()},
+			entries: []string{fs.fi().Name()},
 		}
 		return f, nil
 	}
@@ -80,15 +83,15 @@ func (fs *Reader) OpenFile(name string, flag int, _ bool) (f File, err error) {
 // If the file is a symbolic link, the returned FileInfo
 // describes the symbolic link.  Lstat makes no attempt to follow the link.
 // If there is an error, it will be of type *os.PathError.
-func (fs *Reader) Lstat(name string) (os.FileInfo, error) {
-	getDirInfo := func(name string) os.FileInfo {
+func (fs *Reader) Lstat(name string) (*ExtendedFileInfo, error) {
+	getDirInfo := func(name string) *ExtendedFileInfo {
 		fi := fakeFileInfo{
 			name:    fs.Base(name),
 			size:    0,
 			mode:    os.ModeDir | 0755,
 			modtime: time.Now(),
 		}
-		return fi
+		return &ExtendedFileInfo{FileInfo: fi}
 	}
 
 	switch name {
@@ -112,16 +115,6 @@ func (fs *Reader) Lstat(name string) (os.FileInfo, error) {
 	return nil, pathError("lstat", name, os.ErrNotExist)
 }
 
-func (fs *Reader) DeviceID(_ os.FileInfo) (deviceID uint64, err error) {
-	return 0, errors.New("Device IDs are not supported")
-}
-
-func (fs *Reader) ExtendedStat(fi os.FileInfo) ExtendedFileInfo {
-	return ExtendedFileInfo{
-		FileInfo: fi,
-	}
-}
-
 // Join joins any number of path elements into a single path, adding a
 // Separator if necessary. Join calls Clean on the result; in particular, all
 // empty strings are ignored. On Windows, the result is a UNC path if and only
@@ -165,13 +158,13 @@ func (fs *Reader) Dir(p string) string {
 	return path.Dir(p)
 }
 
-func newReaderFile(rd io.ReadCloser, fi os.FileInfo, allowEmptyFile bool) *readerFile {
+func newReaderFile(rd io.ReadCloser, fi *ExtendedFileInfo, allowEmptyFile bool) *readerFile {
 	return &readerFile{
 		ReadCloser:     rd,
 		AllowEmptyFile: allowEmptyFile,
 		fakeFile: fakeFile{
-			FileInfo: fi,
-			name:     fi.Name(),
+			fi:   fi,
+			name: fi.Name(),
 		},
 	}
 }
@@ -213,7 +206,7 @@ var _ File = &readerFile{}
 // except Stat()
 type fakeFile struct {
 	name string
-	os.FileInfo
+	fi   *ExtendedFileInfo
 }
 
 // ensure that fakeFile implements File
@@ -235,12 +228,12 @@ func (f fakeFile) Close() error {
 	return nil
 }
 
-func (f fakeFile) Stat() (os.FileInfo, error) {
-	return f.FileInfo, nil
+func (f fakeFile) Stat() (*ExtendedFileInfo, error) {
+	return f.fi, nil
 }
 
 func (f fakeFile) ToNode(_ bool) (*restic.Node, error) {
-	node := buildBasicNode(f.name, f.FileInfo)
+	node := buildBasicNode(f.name, f.fi.FileInfo)
 
 	// fill minimal info with current values for uid, gid
 	node.UID = uint32(os.Getuid())
@@ -252,7 +245,7 @@ func (f fakeFile) ToNode(_ bool) (*restic.Node, error) {
 
 // fakeDir implements Readdirnames and Readdir, everything else is delegated to fakeFile.
 type fakeDir struct {
-	entries []os.FileInfo
+	entries []string
 	fakeFile
 }
 
@@ -260,12 +253,7 @@ func (d fakeDir) Readdirnames(n int) ([]string, error) {
 	if n > 0 {
 		return nil, pathError("readdirnames", d.name, errors.New("not implemented"))
 	}
-	names := make([]string, 0, len(d.entries))
-	for _, entry := range d.entries {
-		names = append(names, entry.Name())
-	}
-
-	return names, nil
+	return slices.Clone(d.entries), nil
 }
 
 // fakeFileInfo implements the bare minimum of os.FileInfo.
diff --git a/internal/fs/fs_reader_test.go b/internal/fs/fs_reader_test.go
index 7e7f6e77c..f2e8b2013 100644
--- a/internal/fs/fs_reader_test.go
+++ b/internal/fs/fs_reader_test.go
@@ -60,7 +60,7 @@ func verifyDirectoryContents(t testing.TB, fs FS, dir string, want []string) {
 	}
 }
 
-func checkFileInfo(t testing.TB, fi os.FileInfo, filename string, modtime time.Time, mode os.FileMode, isdir bool) {
+func checkFileInfo(t testing.TB, fi *ExtendedFileInfo, filename string, modtime time.Time, mode os.FileMode, isdir bool) {
 	if fi.IsDir() != isdir {
 		t.Errorf("IsDir returned %t, want %t", fi.IsDir(), isdir)
 	}
@@ -69,8 +69,8 @@ func checkFileInfo(t testing.TB, fi os.FileInfo, filename string, modtime time.T
 		t.Errorf("Mode() returned wrong value, want 0%o, got 0%o", mode, fi.Mode())
 	}
 
-	if !modtime.Equal(time.Time{}) && !fi.ModTime().Equal(modtime) {
-		t.Errorf("ModTime() returned wrong value, want %v, got %v", modtime, fi.ModTime())
+	if !modtime.Equal(time.Time{}) && !fi.FileInfo.ModTime().Equal(modtime) {
+		t.Errorf("ModTime() returned wrong value, want %v, got %v", modtime, fi.FileInfo.ModTime())
 	}
 
 	if path.Base(fi.Name()) != fi.Name() {
diff --git a/internal/fs/interface.go b/internal/fs/interface.go
index 7ff777138..d75b0a91d 100644
--- a/internal/fs/interface.go
+++ b/internal/fs/interface.go
@@ -2,7 +2,6 @@ package fs
 
 import (
 	"io"
-	"os"
 
 	"github.com/restic/restic/internal/restic"
 )
@@ -18,9 +17,7 @@ type FS interface {
 	//
 	// Only the O_NOFOLLOW and O_DIRECTORY flags are supported.
 	OpenFile(name string, flag int, metadataOnly bool) (File, error)
-	Lstat(name string) (os.FileInfo, error)
-	DeviceID(fi os.FileInfo) (deviceID uint64, err error)
-	ExtendedStat(fi os.FileInfo) ExtendedFileInfo
+	Lstat(name string) (*ExtendedFileInfo, error)
 
 	Join(elem ...string) string
 	Separator() string
@@ -47,7 +44,7 @@ type File interface {
 	io.Closer
 
 	Readdirnames(n int) ([]string, error)
-	Stat() (os.FileInfo, error)
+	Stat() (*ExtendedFileInfo, error)
 	// ToNode returns a restic.Node for the File. The internally used os.FileInfo
 	// must be consistent with that returned by Stat(). In particular, the metadata
 	// returned by consecutive calls to Stat() and ToNode() must match.
diff --git a/internal/fs/node.go b/internal/fs/node.go
index 065969537..be91562a4 100644
--- a/internal/fs/node.go
+++ b/internal/fs/node.go
@@ -15,15 +15,14 @@ import (
 
 // nodeFromFileInfo returns a new node from the given path and FileInfo. It
 // returns the first error that is encountered, together with a node.
-func nodeFromFileInfo(path string, fi os.FileInfo, ignoreXattrListError bool) (*restic.Node, error) {
-	node := buildBasicNode(path, fi)
+func nodeFromFileInfo(path string, fi *ExtendedFileInfo, ignoreXattrListError bool) (*restic.Node, error) {
+	node := buildBasicNode(path, fi.FileInfo)
 
-	stat := ExtendedStat(fi)
-	if err := nodeFillExtendedStat(node, path, &stat); err != nil {
+	if err := nodeFillExtendedStat(node, path, fi); err != nil {
 		return node, err
 	}
 
-	err := nodeFillGenericAttributes(node, path, &stat)
+	err := nodeFillGenericAttributes(node, path, fi)
 	err = errors.Join(err, nodeFillExtendedAttributes(node, path, ignoreXattrListError))
 	return node, err
 }
@@ -37,15 +36,15 @@ func buildBasicNode(path string, fi os.FileInfo) *restic.Node {
 		ModTime: fi.ModTime(),
 	}
 
-	node.Type = nodeTypeFromFileInfo(fi)
+	node.Type = nodeTypeFromFileInfo(fi.Mode())
 	if node.Type == restic.NodeTypeFile {
 		node.Size = uint64(fi.Size())
 	}
 	return node
 }
 
-func nodeTypeFromFileInfo(fi os.FileInfo) restic.NodeType {
-	switch fi.Mode() & os.ModeType {
+func nodeTypeFromFileInfo(mode os.FileMode) restic.NodeType {
+	switch mode & os.ModeType {
 	case 0:
 		return restic.NodeTypeFile
 	case os.ModeDir:
diff --git a/internal/fs/stat.go b/internal/fs/stat.go
index e1006fd61..9e5be51e1 100644
--- a/internal/fs/stat.go
+++ b/internal/fs/stat.go
@@ -26,7 +26,7 @@ type ExtendedFileInfo struct {
 }
 
 // ExtendedStat returns an ExtendedFileInfo constructed from the os.FileInfo.
-func ExtendedStat(fi os.FileInfo) ExtendedFileInfo {
+func ExtendedStat(fi os.FileInfo) *ExtendedFileInfo {
 	if fi == nil {
 		panic("os.FileInfo is nil")
 	}
diff --git a/internal/fs/stat_bsd.go b/internal/fs/stat_bsd.go
index 11e075b50..de2254d24 100644
--- a/internal/fs/stat_bsd.go
+++ b/internal/fs/stat_bsd.go
@@ -10,10 +10,10 @@ import (
 )
 
 // extendedStat extracts info into an ExtendedFileInfo for unix based operating systems.
-func extendedStat(fi os.FileInfo) ExtendedFileInfo {
+func extendedStat(fi os.FileInfo) *ExtendedFileInfo {
 	s := fi.Sys().(*syscall.Stat_t)
 
-	extFI := ExtendedFileInfo{
+	return &ExtendedFileInfo{
 		FileInfo:  fi,
 		DeviceID:  uint64(s.Dev),
 		Inode:     uint64(s.Ino),
@@ -29,6 +29,4 @@ func extendedStat(fi os.FileInfo) ExtendedFileInfo {
 		ModTime:    time.Unix(s.Mtimespec.Unix()),
 		ChangeTime: time.Unix(s.Ctimespec.Unix()),
 	}
-
-	return extFI
 }
diff --git a/internal/fs/stat_unix.go b/internal/fs/stat_unix.go
index c55571031..46077402f 100644
--- a/internal/fs/stat_unix.go
+++ b/internal/fs/stat_unix.go
@@ -10,10 +10,10 @@ import (
 )
 
 // extendedStat extracts info into an ExtendedFileInfo for unix based operating systems.
-func extendedStat(fi os.FileInfo) ExtendedFileInfo {
+func extendedStat(fi os.FileInfo) *ExtendedFileInfo {
 	s := fi.Sys().(*syscall.Stat_t)
 
-	extFI := ExtendedFileInfo{
+	return &ExtendedFileInfo{
 		FileInfo:  fi,
 		DeviceID:  uint64(s.Dev),
 		Inode:     s.Ino,
@@ -29,6 +29,4 @@ func extendedStat(fi os.FileInfo) ExtendedFileInfo {
 		ModTime:    time.Unix(s.Mtim.Unix()),
 		ChangeTime: time.Unix(s.Ctim.Unix()),
 	}
-
-	return extFI
 }
diff --git a/internal/fs/stat_windows.go b/internal/fs/stat_windows.go
index 57f330fb5..0dbc429fb 100644
--- a/internal/fs/stat_windows.go
+++ b/internal/fs/stat_windows.go
@@ -11,7 +11,7 @@ import (
 )
 
 // extendedStat extracts info into an ExtendedFileInfo for Windows.
-func extendedStat(fi os.FileInfo) ExtendedFileInfo {
+func extendedStat(fi os.FileInfo) *ExtendedFileInfo {
 	s, ok := fi.Sys().(*syscall.Win32FileAttributeData)
 	if !ok {
 		panic(fmt.Sprintf("conversion to syscall.Win32FileAttributeData failed, type is %T", fi.Sys()))
@@ -31,5 +31,5 @@ func extendedStat(fi os.FileInfo) ExtendedFileInfo {
 	// Windows does not have the concept of a "change time" in the sense Unix uses it, so we're using the LastWriteTime here.
 	extFI.ChangeTime = extFI.ModTime
 
-	return extFI
+	return &extFI
 }

From 847b2efba2ba330b873395d00d7ab34ddd2d30e6 Mon Sep 17 00:00:00 2001
From: Michael Eischer <michael.eischer@fau.de>
Date: Sat, 16 Nov 2024 16:53:34 +0100
Subject: [PATCH 2/3] archiver: remove fs parameter from fileChanged function

---
 internal/archiver/archiver.go      |  4 ++--
 internal/archiver/archiver_test.go | 15 ++++++++-------
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/internal/archiver/archiver.go b/internal/archiver/archiver.go
index f730fe0a5..a89663084 100644
--- a/internal/archiver/archiver.go
+++ b/internal/archiver/archiver.go
@@ -510,7 +510,7 @@ func (arch *Archiver) save(ctx context.Context, snPath, target string, previous
 
 		// check if the file has not changed before performing a fopen operation (more expensive, specially
 		// in network filesystems)
-		if previous != nil && !fileChanged(arch.FS, fi, previous, arch.ChangeIgnoreFlags) {
+		if previous != nil && !fileChanged(fi, previous, arch.ChangeIgnoreFlags) {
 			if arch.allBlobsPresent(previous) {
 				debug.Log("%v hasn't changed, using old list of blobs", target)
 				arch.trackItem(snPath, previous, previous, ItemStats{}, time.Since(start))
@@ -618,7 +618,7 @@ func (arch *Archiver) save(ctx context.Context, snPath, target string, previous
 // fileChanged tries to detect whether a file's content has changed compared
 // to the contents of node, which describes the same path in the parent backup.
 // It should only be run for regular files.
-func fileChanged(fs fs.FS, fi *fs.ExtendedFileInfo, node *restic.Node, ignoreFlags uint) bool {
+func fileChanged(fi *fs.ExtendedFileInfo, node *restic.Node, ignoreFlags uint) bool {
 	switch {
 	case node == nil:
 		return true
diff --git a/internal/archiver/archiver_test.go b/internal/archiver/archiver_test.go
index 038afd11d..0a3fba028 100644
--- a/internal/archiver/archiver_test.go
+++ b/internal/archiver/archiver_test.go
@@ -683,10 +683,11 @@ func TestFileChanged(t *testing.T) {
 			save(t, filename, content)
 
 			fs := &fs.Local{}
-			fiBefore := lstat(t, filename)
+			fiBefore, err := fs.Lstat(filename)
+			rtest.OK(t, err)
 			node := nodeFromFile(t, fs, filename)
 
-			if fileChanged(fs, fiBefore, node, 0) {
+			if fileChanged(fiBefore, node, 0) {
 				t.Fatalf("unchanged file detected as changed")
 			}
 
@@ -696,12 +697,12 @@ func TestFileChanged(t *testing.T) {
 
 			if test.SameFile {
 				// file should be detected as unchanged
-				if fileChanged(fs, fiAfter, node, test.ChangeIgnore) {
+				if fileChanged(fiAfter, node, test.ChangeIgnore) {
 					t.Fatalf("unmodified file detected as changed")
 				}
 			} else {
 				// file should be detected as changed
-				if !fileChanged(fs, fiAfter, node, test.ChangeIgnore) && !test.SameFile {
+				if !fileChanged(fiAfter, node, test.ChangeIgnore) && !test.SameFile {
 					t.Fatalf("modified file detected as unchanged")
 				}
 			}
@@ -718,7 +719,7 @@ func TestFilChangedSpecialCases(t *testing.T) {
 
 	t.Run("nil-node", func(t *testing.T) {
 		fi := lstat(t, filename)
-		if !fileChanged(&fs.Local{}, fi, nil, 0) {
+		if !fileChanged(fi, nil, 0) {
 			t.Fatal("nil node detected as unchanged")
 		}
 	})
@@ -727,7 +728,7 @@ func TestFilChangedSpecialCases(t *testing.T) {
 		fi := lstat(t, filename)
 		node := nodeFromFile(t, &fs.Local{}, filename)
 		node.Type = restic.NodeTypeSymlink
-		if !fileChanged(&fs.Local{}, fi, node, 0) {
+		if !fileChanged(fi, node, 0) {
 			t.Fatal("node with changed type detected as unchanged")
 		}
 	})
@@ -2304,7 +2305,7 @@ func TestMetadataChanged(t *testing.T) {
 
 	// modify the mode by wrapping it in a new struct, uses the consts defined above
 	fs.overrideFI = wrapFileInfo(fi)
-	rtest.Assert(t, !fileChanged(fs, fs.overrideFI, node2, 0), "testfile must not be considered as changed")
+	rtest.Assert(t, !fileChanged(fs.overrideFI, node2, 0), "testfile must not be considered as changed")
 
 	// set the override values in the 'want' node which
 	want.Mode = 0400

From 9a99141a5fe188b59bef37795de9ac9582fd541d Mon Sep 17 00:00:00 2001
From: Michael Eischer <michael.eischer@fau.de>
Date: Sat, 30 Nov 2024 16:58:04 +0100
Subject: [PATCH 3/3] fs: remove os.FileInfo from fs.ExtendedFileInfo

Only the `Sys()` value from os.FileInfo is kept as field `sys` to
support Windows. The os.FileInfo removal ensures that for values like
`ModTime` that existed in both data structures there's no more confusion
which value is actually used.
---
 internal/archiver/archiver.go              |  8 +--
 internal/archiver/archiver_test.go         | 23 ++++++---
 internal/archiver/archiver_unix_test.go    | 44 ----------------
 internal/archiver/archiver_windows_test.go | 38 --------------
 internal/archiver/exclude.go               |  4 +-
 internal/archiver/scanner.go               |  4 +-
 internal/archiver/scanner_test.go          |  2 +-
 internal/fs/fs_local_test.go               | 15 +++---
 internal/fs/fs_local_vss_test.go           |  4 +-
 internal/fs/fs_reader.go                   | 59 +++++-----------------
 internal/fs/fs_reader_test.go              | 20 ++++----
 internal/fs/node.go                        | 14 ++---
 internal/fs/node_windows.go                |  2 +-
 internal/fs/stat.go                        |  6 ++-
 internal/fs/stat_bsd.go                    |  4 +-
 internal/fs/stat_unix.go                   |  4 +-
 internal/fs/stat_windows.go                |  7 ++-
 17 files changed, 80 insertions(+), 178 deletions(-)
 delete mode 100644 internal/archiver/archiver_windows_test.go

diff --git a/internal/archiver/archiver.go b/internal/archiver/archiver.go
index a89663084..55b6ee4b3 100644
--- a/internal/archiver/archiver.go
+++ b/internal/archiver/archiver.go
@@ -505,7 +505,7 @@ func (arch *Archiver) save(ctx context.Context, snPath, target string, previous
 	}
 
 	switch {
-	case fi.Mode().IsRegular():
+	case fi.Mode.IsRegular():
 		debug.Log("  %v regular file", target)
 
 		// check if the file has not changed before performing a fopen operation (more expensive, specially
@@ -555,7 +555,7 @@ func (arch *Archiver) save(ctx context.Context, snPath, target string, previous
 		}
 
 		// make sure it's still a file
-		if !fi.Mode().IsRegular() {
+		if !fi.Mode.IsRegular() {
 			err = errors.Errorf("file %q changed type, refusing to archive", target)
 			return filterError(err)
 		}
@@ -571,7 +571,7 @@ func (arch *Archiver) save(ctx context.Context, snPath, target string, previous
 			arch.trackItem(snPath, previous, node, stats, time.Since(start))
 		})
 
-	case fi.IsDir():
+	case fi.Mode.IsDir():
 		debug.Log("  %v dir", target)
 
 		snItem := snPath + "/"
@@ -592,7 +592,7 @@ func (arch *Archiver) save(ctx context.Context, snPath, target string, previous
 			return futureNode{}, false, err
 		}
 
-	case fi.Mode()&os.ModeSocket > 0:
+	case fi.Mode&os.ModeSocket > 0:
 		debug.Log("  %v is a socket, ignoring", target)
 		return futureNode{}, true, nil
 
diff --git a/internal/archiver/archiver_test.go b/internal/archiver/archiver_test.go
index 0a3fba028..fcc3d465d 100644
--- a/internal/archiver/archiver_test.go
+++ b/internal/archiver/archiver_test.go
@@ -2303,19 +2303,26 @@ func TestMetadataChanged(t *testing.T) {
 		t.Fatalf("metadata does not match:\n%v", cmp.Diff(want, node2))
 	}
 
-	// modify the mode by wrapping it in a new struct, uses the consts defined above
-	fs.overrideFI = wrapFileInfo(fi)
+	// modify the mode and UID/GID
+	modFI := *fi
+	modFI.Mode = mockFileInfoMode
+	if runtime.GOOS != "windows" {
+		modFI.UID = mockFileInfoUID
+		modFI.GID = mockFileInfoGID
+	}
+
+	fs.overrideFI = &modFI
 	rtest.Assert(t, !fileChanged(fs.overrideFI, node2, 0), "testfile must not be considered as changed")
 
 	// set the override values in the 'want' node which
-	want.Mode = 0400
+	want.Mode = mockFileInfoMode
 	// ignore UID and GID on Windows
 	if runtime.GOOS != "windows" {
-		want.UID = 51234
-		want.GID = 51235
+		want.UID = mockFileInfoUID
+		want.GID = mockFileInfoGID
 	}
 	// update mock node accordingly
-	fs.overrideNode.Mode = 0400
+	fs.overrideNode.Mode = want.Mode
 	fs.overrideNode.UID = want.UID
 	fs.overrideNode.GID = want.GID
 
@@ -2456,10 +2463,12 @@ func TestIrregularFile(t *testing.T) {
 
 	tempfile := filepath.Join(tempdir, "testfile")
 	fi := lstat(t, "testfile")
+	// patch mode to irregular
+	fi.Mode = (fi.Mode &^ os.ModeType) | os.ModeIrregular
 
 	override := &overrideFS{
 		FS:         fs.Local{},
-		overrideFI: wrapIrregularFileInfo(fi),
+		overrideFI: fi,
 		overrideNode: &restic.Node{
 			Type: restic.NodeTypeIrregular,
 		},
diff --git a/internal/archiver/archiver_unix_test.go b/internal/archiver/archiver_unix_test.go
index d3e87b57e..b6cc1ba4e 100644
--- a/internal/archiver/archiver_unix_test.go
+++ b/internal/archiver/archiver_unix_test.go
@@ -4,8 +4,6 @@
 package archiver
 
 import (
-	"os"
-	"syscall"
 	"testing"
 
 	"github.com/restic/restic/internal/feature"
@@ -14,48 +12,6 @@ import (
 	rtest "github.com/restic/restic/internal/test"
 )
 
-type wrappedFileInfo struct {
-	os.FileInfo
-	sys  interface{}
-	mode os.FileMode
-}
-
-func (fi wrappedFileInfo) Sys() interface{} {
-	return fi.sys
-}
-
-func (fi wrappedFileInfo) Mode() os.FileMode {
-	return fi.mode
-}
-
-// wrapFileInfo returns a new os.FileInfo with the mode, owner, and group fields changed.
-func wrapFileInfo(fi *fs.ExtendedFileInfo) *fs.ExtendedFileInfo {
-	// get the underlying stat_t and modify the values
-	stat := fi.Sys().(*syscall.Stat_t)
-	stat.Mode = mockFileInfoMode
-	stat.Uid = mockFileInfoUID
-	stat.Gid = mockFileInfoGID
-
-	// wrap the os.FileInfo so we can return a modified stat_t
-	return fs.ExtendedStat(wrappedFileInfo{
-		FileInfo: fi.FileInfo,
-		sys:      stat,
-		mode:     mockFileInfoMode,
-	})
-}
-
-// wrapIrregularFileInfo returns a new os.FileInfo with the mode changed to irregular file
-func wrapIrregularFileInfo(fi *fs.ExtendedFileInfo) *fs.ExtendedFileInfo {
-	// wrap the os.FileInfo so we can return a modified stat_t
-	return &fs.ExtendedFileInfo{
-		FileInfo: wrappedFileInfo{
-			FileInfo: fi.FileInfo,
-			sys:      fi.Sys(),
-			mode:     (fi.Mode() &^ os.ModeType) | os.ModeIrregular,
-		},
-	}
-}
-
 func statAndSnapshot(t *testing.T, repo archiverRepo, name string) (*restic.Node, *restic.Node) {
 	want := nodeFromFile(t, &fs.Local{}, name)
 	_, node := snapshot(t, repo, &fs.Local{}, nil, name)
diff --git a/internal/archiver/archiver_windows_test.go b/internal/archiver/archiver_windows_test.go
deleted file mode 100644
index 2e873c1b7..000000000
--- a/internal/archiver/archiver_windows_test.go
+++ /dev/null
@@ -1,38 +0,0 @@
-//go:build windows
-// +build windows
-
-package archiver
-
-import (
-	"os"
-
-	"github.com/restic/restic/internal/fs"
-)
-
-type wrappedFileInfo struct {
-	os.FileInfo
-	mode os.FileMode
-}
-
-func (fi wrappedFileInfo) Mode() os.FileMode {
-	return fi.mode
-}
-
-// wrapFileInfo returns a new os.FileInfo with the mode, owner, and group fields changed.
-func wrapFileInfo(fi *fs.ExtendedFileInfo) *fs.ExtendedFileInfo {
-	// wrap the os.FileInfo and return the modified mode, uid and gid are ignored on Windows
-	return fs.ExtendedStat(wrappedFileInfo{
-		FileInfo: fi.FileInfo,
-		mode:     mockFileInfoMode,
-	})
-}
-
-// wrapIrregularFileInfo returns a new os.FileInfo with the mode changed to irregular file
-func wrapIrregularFileInfo(fi *fs.ExtendedFileInfo) *fs.ExtendedFileInfo {
-	return &fs.ExtendedFileInfo{
-		FileInfo: wrappedFileInfo{
-			FileInfo: fi.FileInfo,
-			mode:     (fi.Mode() &^ os.ModeType) | os.ModeIrregular,
-		},
-	}
-}
diff --git a/internal/archiver/exclude.go b/internal/archiver/exclude.go
index e1939d292..6db62aa20 100644
--- a/internal/archiver/exclude.go
+++ b/internal/archiver/exclude.go
@@ -267,7 +267,7 @@ func RejectByDevice(samples []string, filesystem fs.FS) (RejectFunc, error) {
 		}
 
 		// reject everything except directories
-		if !fi.IsDir() {
+		if !fi.Mode.IsDir() {
 			return true
 		}
 
@@ -303,7 +303,7 @@ func RejectByDevice(samples []string, filesystem fs.FS) (RejectFunc, error) {
 func RejectBySize(maxSize int64) (RejectFunc, error) {
 	return func(item string, fi *fs.ExtendedFileInfo, _ fs.FS) bool {
 		// directory will be ignored
-		if fi.IsDir() {
+		if fi.Mode.IsDir() {
 			return false
 		}
 
diff --git a/internal/archiver/scanner.go b/internal/archiver/scanner.go
index ebcca0df1..2e6b7210c 100644
--- a/internal/archiver/scanner.go
+++ b/internal/archiver/scanner.go
@@ -118,10 +118,10 @@ func (s *Scanner) scan(ctx context.Context, stats ScanStats, target string) (Sca
 	}
 
 	switch {
-	case fi.Mode().IsRegular():
+	case fi.Mode.IsRegular():
 		stats.Files++
 		stats.Bytes += uint64(fi.Size)
-	case fi.Mode().IsDir():
+	case fi.Mode.IsDir():
 		names, err := fs.Readdirnames(s.FS, target, fs.O_NOFOLLOW)
 		if err != nil {
 			return stats, s.Error(target, err)
diff --git a/internal/archiver/scanner_test.go b/internal/archiver/scanner_test.go
index 0504cb8bd..a47952388 100644
--- a/internal/archiver/scanner_test.go
+++ b/internal/archiver/scanner_test.go
@@ -57,7 +57,7 @@ func TestScanner(t *testing.T) {
 				},
 			},
 			selFn: func(item string, fi *fs.ExtendedFileInfo, fs fs.FS) bool {
-				if fi.IsDir() {
+				if fi.Mode.IsDir() {
 					return true
 				}
 
diff --git a/internal/fs/fs_local_test.go b/internal/fs/fs_local_test.go
index 74cc8b48c..8fd8eb136 100644
--- a/internal/fs/fs_local_test.go
+++ b/internal/fs/fs_local_test.go
@@ -84,7 +84,7 @@ func checkMetadata(t *testing.T, f File, path string, follow bool, nodeType rest
 		fi2, err = os.Lstat(path)
 	}
 	rtest.OK(t, err)
-	assertFIEqual(t, fi2, fi.FileInfo)
+	assertFIEqual(t, fi2, fi)
 
 	node, err := f.ToNode(false)
 	rtest.OK(t, err)
@@ -94,13 +94,12 @@ func checkMetadata(t *testing.T, f File, path string, follow bool, nodeType rest
 	rtest.Equals(t, nodeType, node.Type, "node Type")
 }
 
-func assertFIEqual(t *testing.T, want os.FileInfo, got os.FileInfo) {
+func assertFIEqual(t *testing.T, want os.FileInfo, got *ExtendedFileInfo) {
 	t.Helper()
-	rtest.Equals(t, want.Name(), got.Name(), "Name")
-	rtest.Equals(t, want.IsDir(), got.IsDir(), "IsDir")
-	rtest.Equals(t, want.ModTime(), got.ModTime(), "ModTime")
-	rtest.Equals(t, want.Mode(), got.Mode(), "Mode")
-	rtest.Equals(t, want.Size(), got.Size(), "Size")
+	rtest.Equals(t, want.Name(), got.Name, "Name")
+	rtest.Equals(t, want.ModTime(), got.ModTime, "ModTime")
+	rtest.Equals(t, want.Mode(), got.Mode, "Mode")
+	rtest.Equals(t, want.Size(), got.Size, "Size")
 }
 
 func TestFSLocalRead(t *testing.T) {
@@ -206,7 +205,7 @@ func TestFSLocalTypeChange(t *testing.T) {
 
 	fi, err := f.Stat()
 	rtest.OK(t, err)
-	if !fi.IsDir() {
+	if !fi.Mode.IsDir() {
 		// a file handle based implementation should still reference the file
 		checkMetadata(t, f, pathNew, false, restic.NodeTypeFile)
 
diff --git a/internal/fs/fs_local_vss_test.go b/internal/fs/fs_local_vss_test.go
index 33c412fe9..b64897d1c 100644
--- a/internal/fs/fs_local_vss_test.go
+++ b/internal/fs/fs_local_vss_test.go
@@ -325,7 +325,7 @@ func TestVSSFS(t *testing.T) {
 
 	lstatFi, err := localVss.Lstat(tempfile)
 	rtest.OK(t, err)
-	rtest.Equals(t, origFi.Mode(), lstatFi.Mode())
+	rtest.Equals(t, origFi.Mode, lstatFi.Mode)
 
 	f, err := localVss.OpenFile(tempfile, os.O_RDONLY, false)
 	rtest.OK(t, err)
@@ -335,7 +335,7 @@ func TestVSSFS(t *testing.T) {
 
 	node, err := f.ToNode(false)
 	rtest.OK(t, err)
-	rtest.Equals(t, node.Mode, lstatFi.Mode())
+	rtest.Equals(t, node.Mode, lstatFi.Mode)
 
 	rtest.OK(t, f.Close())
 }
diff --git a/internal/fs/fs_reader.go b/internal/fs/fs_reader.go
index 8b7668730..bbe5c95ab 100644
--- a/internal/fs/fs_reader.go
+++ b/internal/fs/fs_reader.go
@@ -43,12 +43,10 @@ func (fs *Reader) VolumeName(_ string) string {
 
 func (fs *Reader) fi() *ExtendedFileInfo {
 	return &ExtendedFileInfo{
-		FileInfo: fakeFileInfo{
-			name:    fs.Name,
-			size:    fs.Size,
-			mode:    fs.Mode,
-			modtime: fs.ModTime,
-		},
+		Name:    fs.Name,
+		Mode:    fs.Mode,
+		ModTime: fs.ModTime,
+		Size:    fs.Size,
 	}
 }
 
@@ -71,7 +69,7 @@ func (fs *Reader) OpenFile(name string, flag int, _ bool) (f File, err error) {
 		return f, nil
 	case "/", ".":
 		f = fakeDir{
-			entries: []string{fs.fi().Name()},
+			entries: []string{fs.fi().Name},
 		}
 		return f, nil
 	}
@@ -85,13 +83,12 @@ func (fs *Reader) OpenFile(name string, flag int, _ bool) (f File, err error) {
 // If there is an error, it will be of type *os.PathError.
 func (fs *Reader) Lstat(name string) (*ExtendedFileInfo, error) {
 	getDirInfo := func(name string) *ExtendedFileInfo {
-		fi := fakeFileInfo{
-			name:    fs.Base(name),
-			size:    0,
-			mode:    os.ModeDir | 0755,
-			modtime: time.Now(),
+		return &ExtendedFileInfo{
+			Name:    fs.Base(name),
+			Size:    0,
+			Mode:    os.ModeDir | 0755,
+			ModTime: time.Now(),
 		}
-		return &ExtendedFileInfo{FileInfo: fi}
 	}
 
 	switch name {
@@ -164,7 +161,7 @@ func newReaderFile(rd io.ReadCloser, fi *ExtendedFileInfo, allowEmptyFile bool)
 		AllowEmptyFile: allowEmptyFile,
 		fakeFile: fakeFile{
 			fi:   fi,
-			name: fi.Name(),
+			name: fi.Name,
 		},
 	}
 }
@@ -233,7 +230,7 @@ func (f fakeFile) Stat() (*ExtendedFileInfo, error) {
 }
 
 func (f fakeFile) ToNode(_ bool) (*restic.Node, error) {
-	node := buildBasicNode(f.name, f.fi.FileInfo)
+	node := buildBasicNode(f.name, f.fi)
 
 	// fill minimal info with current values for uid, gid
 	node.UID = uint32(os.Getuid())
@@ -256,38 +253,6 @@ func (d fakeDir) Readdirnames(n int) ([]string, error) {
 	return slices.Clone(d.entries), nil
 }
 
-// fakeFileInfo implements the bare minimum of os.FileInfo.
-type fakeFileInfo struct {
-	name    string
-	size    int64
-	mode    os.FileMode
-	modtime time.Time
-}
-
-func (fi fakeFileInfo) Name() string {
-	return fi.name
-}
-
-func (fi fakeFileInfo) Size() int64 {
-	return fi.size
-}
-
-func (fi fakeFileInfo) Mode() os.FileMode {
-	return fi.mode
-}
-
-func (fi fakeFileInfo) ModTime() time.Time {
-	return fi.modtime
-}
-
-func (fi fakeFileInfo) IsDir() bool {
-	return fi.mode&os.ModeDir > 0
-}
-
-func (fi fakeFileInfo) Sys() interface{} {
-	return nil
-}
-
 func pathError(op, name string, err error) *os.PathError {
 	return &os.PathError{Op: op, Path: name, Err: err}
 }
diff --git a/internal/fs/fs_reader_test.go b/internal/fs/fs_reader_test.go
index f2e8b2013..257bfbbac 100644
--- a/internal/fs/fs_reader_test.go
+++ b/internal/fs/fs_reader_test.go
@@ -61,24 +61,24 @@ func verifyDirectoryContents(t testing.TB, fs FS, dir string, want []string) {
 }
 
 func checkFileInfo(t testing.TB, fi *ExtendedFileInfo, filename string, modtime time.Time, mode os.FileMode, isdir bool) {
-	if fi.IsDir() != isdir {
-		t.Errorf("IsDir returned %t, want %t", fi.IsDir(), isdir)
+	if fi.Mode.IsDir() != isdir {
+		t.Errorf("IsDir returned %t, want %t", fi.Mode.IsDir(), isdir)
 	}
 
-	if fi.Mode() != mode {
-		t.Errorf("Mode() returned wrong value, want 0%o, got 0%o", mode, fi.Mode())
+	if fi.Mode != mode {
+		t.Errorf("Mode has wrong value, want 0%o, got 0%o", mode, fi.Mode)
 	}
 
-	if !modtime.Equal(time.Time{}) && !fi.FileInfo.ModTime().Equal(modtime) {
-		t.Errorf("ModTime() returned wrong value, want %v, got %v", modtime, fi.FileInfo.ModTime())
+	if !modtime.Equal(time.Time{}) && !fi.ModTime.Equal(modtime) {
+		t.Errorf("ModTime has wrong value, want %v, got %v", modtime, fi.ModTime)
 	}
 
-	if path.Base(fi.Name()) != fi.Name() {
-		t.Errorf("Name() returned is not base, want %q, got %q", path.Base(fi.Name()), fi.Name())
+	if path.Base(fi.Name) != fi.Name {
+		t.Errorf("Name is not base, want %q, got %q", path.Base(fi.Name), fi.Name)
 	}
 
-	if fi.Name() != path.Base(filename) {
-		t.Errorf("Name() returned wrong value, want %q, got %q", path.Base(filename), fi.Name())
+	if fi.Name != path.Base(filename) {
+		t.Errorf("Name has wrong value, want %q, got %q", path.Base(filename), fi.Name)
 	}
 }
 
diff --git a/internal/fs/node.go b/internal/fs/node.go
index be91562a4..058d9cc7b 100644
--- a/internal/fs/node.go
+++ b/internal/fs/node.go
@@ -16,7 +16,7 @@ import (
 // nodeFromFileInfo returns a new node from the given path and FileInfo. It
 // returns the first error that is encountered, together with a node.
 func nodeFromFileInfo(path string, fi *ExtendedFileInfo, ignoreXattrListError bool) (*restic.Node, error) {
-	node := buildBasicNode(path, fi.FileInfo)
+	node := buildBasicNode(path, fi)
 
 	if err := nodeFillExtendedStat(node, path, fi); err != nil {
 		return node, err
@@ -27,18 +27,18 @@ func nodeFromFileInfo(path string, fi *ExtendedFileInfo, ignoreXattrListError bo
 	return node, err
 }
 
-func buildBasicNode(path string, fi os.FileInfo) *restic.Node {
+func buildBasicNode(path string, fi *ExtendedFileInfo) *restic.Node {
 	mask := os.ModePerm | os.ModeType | os.ModeSetuid | os.ModeSetgid | os.ModeSticky
 	node := &restic.Node{
 		Path:    path,
-		Name:    fi.Name(),
-		Mode:    fi.Mode() & mask,
-		ModTime: fi.ModTime(),
+		Name:    fi.Name,
+		Mode:    fi.Mode & mask,
+		ModTime: fi.ModTime,
 	}
 
-	node.Type = nodeTypeFromFileInfo(fi.Mode())
+	node.Type = nodeTypeFromFileInfo(fi.Mode)
 	if node.Type == restic.NodeTypeFile {
-		node.Size = uint64(fi.Size())
+		node.Size = uint64(fi.Size)
 	}
 	return node
 }
diff --git a/internal/fs/node_windows.go b/internal/fs/node_windows.go
index c0f8b08b0..74cf6c0e5 100644
--- a/internal/fs/node_windows.go
+++ b/internal/fs/node_windows.go
@@ -361,7 +361,7 @@ func nodeFillGenericAttributes(node *restic.Node, path string, stat *ExtendedFil
 		}
 	}
 
-	winFI := stat.Sys().(*syscall.Win32FileAttributeData)
+	winFI := stat.sys.(*syscall.Win32FileAttributeData)
 
 	// Add Windows attributes
 	node.GenericAttributes, err = restic.WindowsAttrsToGenericAttributes(restic.WindowsAttributes{
diff --git a/internal/fs/stat.go b/internal/fs/stat.go
index 9e5be51e1..bd3993f41 100644
--- a/internal/fs/stat.go
+++ b/internal/fs/stat.go
@@ -8,7 +8,8 @@ import (
 // ExtendedFileInfo is an extended stat_t, filled with attributes that are
 // supported by most operating systems. The original FileInfo is embedded.
 type ExtendedFileInfo struct {
-	os.FileInfo
+	Name string
+	Mode os.FileMode
 
 	DeviceID  uint64 // ID of device containing the file
 	Inode     uint64 // Inode number
@@ -23,6 +24,9 @@ type ExtendedFileInfo struct {
 	AccessTime time.Time // last access time stamp
 	ModTime    time.Time // last (content) modification time stamp
 	ChangeTime time.Time // last status change time stamp
+
+	// nolint:unused // only used on Windows
+	sys any // Value returned by os.FileInfo.Sys()
 }
 
 // ExtendedStat returns an ExtendedFileInfo constructed from the os.FileInfo.
diff --git a/internal/fs/stat_bsd.go b/internal/fs/stat_bsd.go
index de2254d24..165064153 100644
--- a/internal/fs/stat_bsd.go
+++ b/internal/fs/stat_bsd.go
@@ -14,7 +14,9 @@ func extendedStat(fi os.FileInfo) *ExtendedFileInfo {
 	s := fi.Sys().(*syscall.Stat_t)
 
 	return &ExtendedFileInfo{
-		FileInfo:  fi,
+		Name: fi.Name(),
+		Mode: fi.Mode(),
+
 		DeviceID:  uint64(s.Dev),
 		Inode:     uint64(s.Ino),
 		Links:     uint64(s.Nlink),
diff --git a/internal/fs/stat_unix.go b/internal/fs/stat_unix.go
index 46077402f..723ac8b19 100644
--- a/internal/fs/stat_unix.go
+++ b/internal/fs/stat_unix.go
@@ -14,7 +14,9 @@ func extendedStat(fi os.FileInfo) *ExtendedFileInfo {
 	s := fi.Sys().(*syscall.Stat_t)
 
 	return &ExtendedFileInfo{
-		FileInfo:  fi,
+		Name: fi.Name(),
+		Mode: fi.Mode(),
+
 		DeviceID:  uint64(s.Dev),
 		Inode:     s.Ino,
 		Links:     uint64(s.Nlink),
diff --git a/internal/fs/stat_windows.go b/internal/fs/stat_windows.go
index 0dbc429fb..a2dfa5f6d 100644
--- a/internal/fs/stat_windows.go
+++ b/internal/fs/stat_windows.go
@@ -18,8 +18,11 @@ func extendedStat(fi os.FileInfo) *ExtendedFileInfo {
 	}
 
 	extFI := ExtendedFileInfo{
-		FileInfo: fi,
-		Size:     int64(s.FileSizeLow) | (int64(s.FileSizeHigh) << 32),
+		Name: fi.Name(),
+		Mode: fi.Mode(),
+
+		Size: int64(s.FileSizeLow) | (int64(s.FileSizeHigh) << 32),
+		sys:  fi.Sys(),
 	}
 
 	atime := syscall.NsecToTimespec(s.LastAccessTime.Nanoseconds())