From 1cb9e9b44e7140d14dd42d48b2a7c038b65e8f16 Mon Sep 17 00:00:00 2001
From: John Howard <jhoward@microsoft.com>
Date: Mon, 8 Aug 2016 14:25:33 -0700
Subject: [PATCH] Windows: Block ReFS file systems

Signed-off-by: John Howard <jhoward@microsoft.com>
---
 daemon/graphdriver/windows/windows.go | 41 +++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/daemon/graphdriver/windows/windows.go b/daemon/graphdriver/windows/windows.go
index 7c34b2039b..1bb2d94bac 100644
--- a/daemon/graphdriver/windows/windows.go
+++ b/daemon/graphdriver/windows/windows.go
@@ -6,6 +6,7 @@ import (
 	"bufio"
 	"bytes"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -67,6 +68,15 @@ func isTP5OrOlder() bool {
 // InitFilter returns a new Windows storage filter driver.
 func InitFilter(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (graphdriver.Driver, error) {
 	logrus.Debugf("WindowsGraphDriver InitFilter at %s", home)
+
+	fsType, err := getFileSystemType(string(home[0]))
+	if err != nil {
+		return nil, err
+	}
+	if strings.ToLower(fsType) == "refs" {
+		return nil, fmt.Errorf("%s is on an ReFS volume - ReFS volumes are not supported", home)
+	}
+
 	d := &Driver{
 		info: hcsshim.DriverInfo{
 			HomeDir: home,
@@ -78,6 +88,37 @@ func InitFilter(home string, options []string, uidMaps, gidMaps []idtools.IDMap)
 	return d, nil
 }
 
+// win32FromHresult is a helper function to get the win32 error code from an HRESULT
+func win32FromHresult(hr uintptr) uintptr {
+	if hr&0x1fff0000 == 0x00070000 {
+		return hr & 0xffff
+	}
+	return hr
+}
+
+// getFileSystemType obtains the type of a file system through GetVolumeInformation
+// https://msdn.microsoft.com/en-us/library/windows/desktop/aa364993(v=vs.85).aspx
+func getFileSystemType(drive string) (fsType string, hr error) {
+	var (
+		modkernel32              = syscall.NewLazyDLL("kernel32.dll")
+		procGetVolumeInformation = modkernel32.NewProc("GetVolumeInformationW")
+		buf                      = make([]uint16, 255)
+		size                     = syscall.MAX_PATH + 1
+	)
+	if len(drive) != 1 {
+		hr = errors.New("getFileSystemType must be called with a drive letter")
+		return
+	}
+	drive += `:\`
+	n := uintptr(unsafe.Pointer(nil))
+	r0, _, _ := syscall.Syscall9(procGetVolumeInformation.Addr(), 8, uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(drive))), n, n, n, n, n, uintptr(unsafe.Pointer(&buf[0])), uintptr(size), 0)
+	if int32(r0) < 0 {
+		hr = syscall.Errno(win32FromHresult(r0))
+	}
+	fsType = syscall.UTF16ToString(buf)
+	return
+}
+
 // String returns the string representation of a driver. This should match
 // the name the graph driver has been registered with.
 func (d *Driver) String() string {