From 348e966daa0c73a2ba9a905c903f86f2cd37601a Mon Sep 17 00:00:00 2001
From: greatroar <61184462+greatroar@users.noreply.github.com>
Date: Fri, 11 Nov 2022 14:53:42 +0100
Subject: [PATCH] backend/local: Ignore ENOTTY for fsync on Mac

Fixes #4016.
---
 changelog/unreleased/issue-4016         |  8 ++++++++
 internal/backend/local/local.go         |  2 +-
 internal/backend/local/local_unix.go    | 14 +++++++++++++-
 internal/backend/local/local_windows.go |  3 +++
 4 files changed, 25 insertions(+), 2 deletions(-)
 create mode 100644 changelog/unreleased/issue-4016

diff --git a/changelog/unreleased/issue-4016 b/changelog/unreleased/issue-4016
new file mode 100644
index 000000000..bf0b86409
--- /dev/null
+++ b/changelog/unreleased/issue-4016
@@ -0,0 +1,8 @@
+Bugfix: Support ExFAT-formatted local backends on macOS Ventura
+
+ExFAT-formatted disks could not be used as local backends starting from macOS
+Ventura. Restic commands would fail with "inappropriate ioctl for device". This
+has been fixed.
+
+https://github.com/restic/restic/issues/4016
+https://github.com/restic/restic/pull/4021
diff --git a/internal/backend/local/local.go b/internal/backend/local/local.go
index bce83d768..71f341dfa 100644
--- a/internal/backend/local/local.go
+++ b/internal/backend/local/local.go
@@ -177,7 +177,7 @@ func (b *Local) Save(ctx context.Context, h restic.Handle, rd restic.RewindReade
 
 	// Ignore error if filesystem does not support fsync.
 	err = f.Sync()
-	syncNotSup := errors.Is(err, syscall.ENOTSUP)
+	syncNotSup := err != nil && (errors.Is(err, syscall.ENOTSUP) || isMacENOTTY(err))
 	if err != nil && !syncNotSup {
 		return errors.WithStack(err)
 	}
diff --git a/internal/backend/local/local_unix.go b/internal/backend/local/local_unix.go
index 3dde753a8..e3256ed7a 100644
--- a/internal/backend/local/local_unix.go
+++ b/internal/backend/local/local_unix.go
@@ -6,6 +6,7 @@ package local
 import (
 	"errors"
 	"os"
+	"runtime"
 	"syscall"
 
 	"github.com/restic/restic/internal/fs"
@@ -19,7 +20,9 @@ func fsyncDir(dir string) error {
 	}
 
 	err = d.Sync()
-	if errors.Is(err, syscall.ENOTSUP) || errors.Is(err, syscall.ENOENT) || errors.Is(err, syscall.EINVAL) {
+	if err != nil &&
+		(errors.Is(err, syscall.ENOTSUP) || errors.Is(err, syscall.ENOENT) ||
+			errors.Is(err, syscall.EINVAL) || isMacENOTTY(err)) {
 		err = nil
 	}
 
@@ -31,6 +34,15 @@ func fsyncDir(dir string) error {
 	return err
 }
 
+// The ExFAT driver on some versions of macOS can return ENOTTY,
+// "inappropriate ioctl for device", for fsync.
+//
+// https://github.com/restic/restic/issues/4016
+// https://github.com/realm/realm-core/issues/5789
+func isMacENOTTY(err error) bool {
+	return runtime.GOOS == "darwin" && errors.Is(err, syscall.ENOTTY)
+}
+
 // set file to readonly
 func setFileReadonly(f string, mode os.FileMode) error {
 	return fs.Chmod(f, mode&^0222)
diff --git a/internal/backend/local/local_windows.go b/internal/backend/local/local_windows.go
index 72ced630c..d69b9eec8 100644
--- a/internal/backend/local/local_windows.go
+++ b/internal/backend/local/local_windows.go
@@ -7,6 +7,9 @@ import (
 // Can't explicitly flush directory changes on Windows.
 func fsyncDir(dir string) error { return nil }
 
+// Windows is not macOS.
+func isMacENOTTY(err error) bool { return false }
+
 // We don't modify read-only on windows,
 // since it will make us unable to delete the file,
 // and this isn't common practice on this platform.