Merge pull request #223 from dmcgowan/support-darwin-clonefile

Support darwin clonefile

fs/copy.go

@@ -184,6 +184,10 @@ func copyDirectory(dst, src string, inodes map[uint64]string, o *copyDirOpts) er
 // CopyFile copies the source file to the target.
 // The most efficient means of copying is used for the platform.
 func CopyFile(target, source string) error {
+	return copyFile(target, source)
+}
+
+func openAndCopyFile(target, source string) error {
 	src, err := os.Open(source)
 	if err != nil {
 		return fmt.Errorf("failed to open source %s: %w", source, err)

fs/copy_darwin.go

@@ -0,0 +1,35 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package fs
+
+import (
+	"errors"
+	"fmt"
+
+	"golang.org/x/sys/unix"
+)
+
+func copyFile(target, source string) error {
+	if err := unix.Clonefile(source, target, unix.CLONE_NOFOLLOW); err != nil {
+		if !errors.Is(err, unix.ENOTSUP) {
+			return fmt.Errorf("clonefile failed: %w", err)
+		}
+
+		return openAndCopyFile(target, source)
+	}
+	return nil
+}

fs/copy_nondarwin.go

@@ -0,0 +1,22 @@
+//go:build !darwin
+// +build !darwin
+
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package fs
+
+var copyFile = openAndCopyFile

fs/copy_test.go

@@ -19,6 +19,7 @@ package fs
 import (
 	_ "crypto/sha256"
 	"fmt"
+	"os"
 	"testing"
 	"time"
 
@@ -89,3 +90,37 @@ func testCopy(t testing.TB, apply fstest.Applier) error {
 
 	return fstest.CheckDirectoryEqual(t1, t2)
 }
+
+func BenchmarkLargeCopy100MB(b *testing.B) {
+	benchmarkLargeCopyFile(b, 100*1024*1024)
+}
+
+func BenchmarkLargeCopy1GB(b *testing.B) {
+	benchmarkLargeCopyFile(b, 1024*1024*1024)
+}
+
+func benchmarkLargeCopyFile(b *testing.B, size int64) {
+	b.StopTimer()
+	base := b.TempDir()
+	apply := fstest.Apply(
+		fstest.CreateRandomFile("/large", time.Now().UnixNano(), size, 0o644),
+	)
+	if err := apply.Apply(base); err != nil {
+		b.Fatal("failed to apply changes:", err)
+	}
+
+	for i := 0; i < b.N; i++ {
+		copied := b.TempDir()
+		b.StartTimer()
+		if err := CopyDir(copied, base); err != nil {
+			b.Fatal("failed to copy:", err)
+		}
+		b.StopTimer()
+		if i == 0 {
+			if err := fstest.CheckDirectoryEqual(base, copied); err != nil {
+				b.Fatal("check failed:", err)
+			}
+		}
+		os.RemoveAll(copied)
+	}
+}