backend: consistently use os package for filesystem access

The go std library should be good enough to manage the files in the
backend and cache folders.

internal/backend/cache/cache.go

@@ -12,7 +12,6 @@ import (
 	"github.com/pkg/errors"
 	"github.com/restic/restic/internal/backend"
 	"github.com/restic/restic/internal/debug"
-	"github.com/restic/restic/internal/fs"
 	"github.com/restic/restic/internal/restic"
 )
 
@@ -54,7 +53,7 @@ const cachedirTagSignature = "Signature: 8a477f597d28d172789f06886806bc55\n"
 
 func writeCachedirTag(dir string) error {
 	tagfile := filepath.Join(dir, "CACHEDIR.TAG")
-	f, err := fs.OpenFile(tagfile, os.O_CREATE|os.O_EXCL|os.O_WRONLY, fileMode)
+	f, err := os.OpenFile(tagfile, os.O_CREATE|os.O_EXCL|os.O_WRONLY, fileMode)
 	if err != nil {
 		if errors.Is(err, os.ErrExist) {
 			return nil
@@ -85,7 +84,7 @@ func New(id string, basedir string) (c *Cache, err error) {
 		}
 	}
 
-	err = fs.MkdirAll(basedir, dirMode)
+	err = os.MkdirAll(basedir, dirMode)
 	if err != nil {
 		return nil, errors.WithStack(err)
 	}
@@ -113,7 +112,7 @@ func New(id string, basedir string) (c *Cache, err error) {
 
 	case errors.Is(err, os.ErrNotExist):
 		// Create the repo cache dir. The parent exists, so Mkdir suffices.
-		err := fs.Mkdir(cachedir, dirMode)
+		err := os.Mkdir(cachedir, dirMode)
 		switch {
 		case err == nil:
 			created = true
@@ -134,7 +133,7 @@ func New(id string, basedir string) (c *Cache, err error) {
 	}
 
 	for _, p := range cacheLayoutPaths {
-		if err = fs.MkdirAll(filepath.Join(cachedir, p), dirMode); err != nil {
+		if err = os.MkdirAll(filepath.Join(cachedir, p), dirMode); err != nil {
 			return nil, errors.WithStack(err)
 		}
 	}
@@ -152,7 +151,7 @@ func New(id string, basedir string) (c *Cache, err error) {
 // directory d to the current time.
 func updateTimestamp(d string) error {
 	t := time.Now()
-	return fs.Chtimes(d, t, t)
+	return os.Chtimes(d, t, t)
 }
 
 // MaxCacheAge is the default age (30 days) after which cache directories are considered old.
@@ -165,7 +164,7 @@ func validCacheDirName(s string) bool {
 
 // listCacheDirs returns the list of cache directories.
 func listCacheDirs(basedir string) ([]os.FileInfo, error) {
-	f, err := fs.Open(basedir)
+	f, err := os.Open(basedir)
 	if err != nil {
 		if errors.Is(err, os.ErrNotExist) {
 			err = nil

internal/backend/cache/file.go

@@ -12,7 +12,6 @@ import (
 	"github.com/restic/restic/internal/backend/util"
 	"github.com/restic/restic/internal/crypto"
 	"github.com/restic/restic/internal/debug"
-	"github.com/restic/restic/internal/fs"
 	"github.com/restic/restic/internal/restic"
 )
 
@@ -44,7 +43,7 @@ func (c *Cache) load(h backend.Handle, length int, offset int64) (io.ReadCloser,
 		return nil, false, errors.New("cannot be cached")
 	}
 
-	f, err := fs.Open(c.filename(h))
+	f, err := os.Open(c.filename(h))
 	if err != nil {
 		return nil, false, errors.WithStack(err)
 	}
@@ -91,7 +90,7 @@ func (c *Cache) save(h backend.Handle, rd io.Reader) error {
 
 	finalname := c.filename(h)
 	dir := filepath.Dir(finalname)
-	err := fs.Mkdir(dir, 0700)
+	err := os.Mkdir(dir, 0700)
 	if err != nil && !errors.Is(err, os.ErrExist) {
 		return err
 	}
@@ -106,26 +105,26 @@ func (c *Cache) save(h backend.Handle, rd io.Reader) error {
 	n, err := io.Copy(f, rd)
 	if err != nil {
 		_ = f.Close()
-		_ = fs.Remove(f.Name())
+		_ = os.Remove(f.Name())
 		return errors.Wrap(err, "Copy")
 	}
 
 	if n <= int64(crypto.CiphertextLength(0)) {
 		_ = f.Close()
-		_ = fs.Remove(f.Name())
+		_ = os.Remove(f.Name())
 		debug.Log("trying to cache truncated file %v, removing", h)
 		return nil
 	}
 
 	// Close, then rename. Windows doesn't like the reverse order.
 	if err = f.Close(); err != nil {
-		_ = fs.Remove(f.Name())
+		_ = os.Remove(f.Name())
 		return errors.WithStack(err)
 	}
 
-	err = fs.Rename(f.Name(), finalname)
+	err = os.Rename(f.Name(), finalname)
 	if err != nil {
-		_ = fs.Remove(f.Name())
+		_ = os.Remove(f.Name())
 	}
 	if runtime.GOOS == "windows" && errors.Is(err, os.ErrPermission) {
 		// On Windows, renaming over an existing file is ok
@@ -162,7 +161,7 @@ func (c *Cache) remove(h backend.Handle) (bool, error) {
 		return false, nil
 	}
 
-	err := fs.Remove(c.filename(h))
+	err := os.Remove(c.filename(h))
 	removed := err == nil
 	if errors.Is(err, os.ErrNotExist) {
 		err = nil
@@ -189,7 +188,7 @@ func (c *Cache) Clear(t restic.FileType, valid restic.IDSet) error {
 		}
 
 		// ignore ErrNotExist to gracefully handle multiple processes running Clear() concurrently
-		if err = fs.Remove(c.filename(backend.Handle{Type: t, Name: id.String()})); err != nil && !errors.Is(err, os.ErrNotExist) {
+		if err = os.Remove(c.filename(backend.Handle{Type: t, Name: id.String()})); err != nil && !errors.Is(err, os.ErrNotExist) {
 			return err
 		}
 	}
@@ -236,6 +235,6 @@ func (c *Cache) Has(h backend.Handle) bool {
 		return false
 	}
 
-	_, err := fs.Stat(c.filename(h))
+	_, err := os.Stat(c.filename(h))
 	return err == nil
 }

internal/backend/cache/file_test.go

@@ -12,7 +12,6 @@ import (
 
 	"github.com/restic/restic/internal/backend"
 	"github.com/restic/restic/internal/errors"
-	"github.com/restic/restic/internal/fs"
 	"github.com/restic/restic/internal/restic"
 	rtest "github.com/restic/restic/internal/test"
 
@@ -278,7 +277,7 @@ func TestFileSaveConcurrent(t *testing.T) {
 
 func TestFileSaveAfterDamage(t *testing.T) {
 	c := TestNewCache(t)
-	rtest.OK(t, fs.RemoveAll(c.path))
+	rtest.OK(t, os.RemoveAll(c.path))
 
 	// save a few bytes of data in the cache
 	data := rtest.Random(123456789, 42)