Block dev for restore (#10013)

* add block dev operations for block uploader restore

Signed-off-by: Lyndon-Li <lyonghui@vmware.com>

* add block dev operations for block uploader restore

Signed-off-by: Lyndon-Li <lyonghui@vmware.com>

---------

Signed-off-by: Lyndon-Li <lyonghui@vmware.com>

changelogs/unreleased/10013-Lyndon-Li

@@ -0,0 +1 @@
+Add block dev restore operations for block data mover

pkg/uploader/block/dev_linux.go

@@ -23,6 +23,7 @@ import (
 	"os"
 	"path/filepath"
 	"syscall"
+	"unsafe"
 
 	"github.com/cockroachdb/errors"
 )
@@ -76,3 +77,29 @@ func resolveSymlink(path string) (string, error) {
 
 	return filepath.EvalSymlinks(path)
 }
+
+func blkZeroOut(dest *os.File, start int64, length int64) error {
+	const BLKZEROOUT = 0x127b
+
+	zeroRange := [2]uint64{uint64(start), uint64(length)}
+
+	rawConn, err := dest.SyscallConn()
+	if err != nil {
+		return errors.Wrap(err, "error getting raw connection")
+	}
+
+	ioctlErr := syscall.Errno(0)
+	if err := rawConn.Control(func(fd uintptr) {
+		if _, _, errno := syscall.Syscall(syscall.SYS_IOCTL, fd, BLKZEROOUT, uintptr(unsafe.Pointer(&zeroRange[0]))); errno != 0 {
+			ioctlErr = errno
+		}
+	}); err != nil {
+		return errors.Wrap(err, "error controlling block dev")
+	}
+
+	if ioctlErr != 0 {
+		return errors.Wrapf(ioctlErr, "error calling ioctl on block dev")
+	}
+
+	return nil
+}

pkg/uploader/block/dev_linux_test.go

@@ -26,6 +26,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/cockroachdb/errors"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -356,3 +357,30 @@ func TestOpenBlockDevice(t *testing.T) {
 		})
 	}
 }
+
+func TestBlkZeroOut(t *testing.T) {
+	t.Run("closed file returns error", func(t *testing.T) {
+		f, err := os.CreateTemp(t.TempDir(), "blkzeroout-test-*")
+		require.NoError(t, err)
+		err = f.Close()
+		require.NoError(t, err)
+
+		err = blkZeroOut(f, 0, 1024)
+		assert.Error(t, err)
+	})
+
+	t.Run("regular file returns ioctl error", func(t *testing.T) {
+		f, err := os.CreateTemp(t.TempDir(), "blkzeroout-test-*")
+		require.NoError(t, err)
+		defer f.Close()
+
+		err = blkZeroOut(f, 0, 1024)
+		require.Error(t, err)
+		assert.Contains(t, err.Error(), "error calling ioctl on block dev")
+
+		// On regular files, ioctl with BLKZEROOUT should fail with ENOTTY (inappropriate ioctl for device) or EINVAL
+		isENOTTY := errors.Is(err, syscall.ENOTTY)
+		isEINVAL := errors.Is(err, syscall.EINVAL)
+		assert.True(t, isENOTTY || isEINVAL, "expected error to be ENOTTY or EINVAL, got: %v", err)
+	})
+}

pkg/uploader/block/dev_other.go

@@ -27,3 +27,7 @@ import (
 func openBlockDevice(_ string, _ bool) (*os.File, error) {
 	return nil, fmt.Errorf("block mode is not supported for non-linux platforms")
 }
+
+func blkZeroOut(_ *os.File, _ int64, _ int64) error {
+	return fmt.Errorf("block mode is not supported for non-linux platforms")
+}