Remove OS-specific versions of fs.MkdirAll

Go has supported Windows paths correctly since 1.11, see
https://github.com/golang/go/issues/10900 and the commit referenced
there.

internal/fs/file.go

@@ -12,6 +12,14 @@ func Mkdir(name string, perm os.FileMode) error {
 	return os.Mkdir(fixpath(name), perm)
 }
 
+// MkdirAll creates a directory named path, along with any necessary parents,
+// and returns nil, or else returns an error. The permission bits perm are used
+// for all directories that MkdirAll creates. If path is already a directory,
+// MkdirAll does nothing and returns nil.
+func MkdirAll(path string, perm os.FileMode) error {
+	return os.MkdirAll(fixpath(path), perm)
+}
+
 // Readlink returns the destination of the named symbolic link.
 // If there is an error, it will be of type *PathError.
 func Readlink(name string) (string, error) {

internal/fs/file_unix.go

@@ -14,14 +14,6 @@ func fixpath(name string) string {
 	return name
 }
 
-// MkdirAll creates a directory named path, along with any necessary parents,
-// and returns nil, or else returns an error. The permission bits perm are used
-// for all directories that MkdirAll creates. If path is already a directory,
-// MkdirAll does nothing and returns nil.
-func MkdirAll(path string, perm os.FileMode) error {
-	return os.MkdirAll(fixpath(path), perm)
-}
-
 // TempFile creates a temporary file which has already been deleted (on
 // supported platforms)
 func TempFile(dir, prefix string) (f *os.File, err error) {

internal/fs/file_windows.go

@@ -5,7 +5,6 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
-	"syscall"
 )
 
 // fixpath returns an absolute path on windows, so restic can open long file
@@ -31,62 +30,6 @@ func fixpath(name string) string {
 	return name
 }
 
-// MkdirAll creates a directory named path, along with any necessary parents,
-// and returns nil, or else returns an error. The permission bits perm are used
-// for all directories that MkdirAll creates. If path is already a directory,
-// MkdirAll does nothing and returns nil.
-//
-// Adapted from the stdlib MkdirAll, added test for volume name.
-func MkdirAll(path string, perm os.FileMode) error {
-	// Fast path: if we can tell whether path is a directory or file, stop with success or error.
-	dir, err := os.Stat(path)
-	if err == nil {
-		if dir.IsDir() {
-			return nil
-		}
-		return &os.PathError{
-			Op:   "mkdir",
-			Path: path,
-			Err:  syscall.ENOTDIR,
-		}
-	}
-
-	// Slow path: make sure parent exists and then call Mkdir for path.
-	i := len(path)
-	for i > 0 && os.IsPathSeparator(path[i-1]) { // Skip trailing path separator.
-		i--
-	}
-
-	j := i
-	for j > 0 && !os.IsPathSeparator(path[j-1]) { // Scan backward over element.
-		j--
-	}
-
-	if j > 1 {
-		// Create parent
-		parent := path[0 : j-1]
-		if parent != filepath.VolumeName(parent) {
-			err = MkdirAll(parent, perm)
-			if err != nil {
-				return err
-			}
-		}
-	}
-
-	// Parent now exists; invoke Mkdir and use its result.
-	err = os.Mkdir(path, perm)
-	if err != nil {
-		// Handle arguments like "foo/." by
-		// double-checking that directory doesn't exist.
-		dir, err1 := os.Lstat(path)
-		if err1 == nil && dir.IsDir() {
-			return nil
-		}
-		return err
-	}
-	return nil
-}
-
 // TempFile creates a temporary file.
 func TempFile(dir, prefix string) (f *os.File, err error) {
 	return ioutil.TempFile(dir, prefix)