devmapper: don't create too new xfs

Since the update to Debian Stretch, devmapper unit test fails. One
reason is, the combination of somewhat old (less than 3.16) kernel and
relatively new xfsprogs leads to creating a filesystem which is not supported
by the kernel:

> [12206.467518] XFS (dm-1): Superblock has unknown read-only compatible features (0x1) enabled.
> [12206.472046] XFS (dm-1): Attempted to mount read-only compatible filesystem read-write.
> Filesystem can only be safely mounted read only.
> [12206.472079] XFS (dm-1): SB validate failed with error 22.

Ideally, that would be automatically and implicitly handled by xfsprogs.
In real life, we have to take care about it here. Sigh.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

daemon/graphdriver/devmapper/deviceset.go

@@ -25,6 +25,7 @@ import (
 	"github.com/docker/docker/pkg/loopback"
 	"github.com/docker/docker/pkg/mount"
 	"github.com/docker/docker/pkg/parsers"
+	"github.com/docker/docker/pkg/parsers/kernel"
 	units "github.com/docker/go-units"
 	"github.com/opencontainers/selinux/go-selinux/label"
 	"github.com/pkg/errors"
@@ -572,13 +573,19 @@ func determineDefaultFS() string {
 	return "ext4"
 }
 
-func (devices *DeviceSet) createFilesystem(info *devInfo) (err error) {
-	devname := info.DevName()
+// mkfsOptions tries to figure out whether some additional mkfs options are required
+func mkfsOptions(fs string) []string {
+	if fs == "xfs" && !kernel.CheckKernelVersion(3, 16, 0) {
+		// For kernels earlier than 3.16 (and newer xfsutils),
+		// some xfs features need to be explicitly disabled.
+		return []string{"-m", "crc=0,finobt=0"}
+	}
 
-	args := []string{}
-	args = append(args, devices.mkfsArgs...)
+	return []string{}
+}
 
-	args = append(args, devname)
+func (devices *DeviceSet) createFilesystem(info *devInfo) (err error) {
+	devname := info.DevName()
 
 	if devices.filesystem == "" {
 		devices.filesystem = determineDefaultFS()
@@ -587,7 +594,11 @@ func (devices *DeviceSet) createFilesystem(info *devInfo) (err error) {
 		return err
 	}
 
-	logrus.Infof("devmapper: Creating filesystem %s on device %s", devices.filesystem, info.Name())
+	args := mkfsOptions(devices.filesystem)
+	args = append(args, devices.mkfsArgs...)
+	args = append(args, devname)
+
+	logrus.Infof("devmapper: Creating filesystem %s on device %s, mkfs args: %v", devices.filesystem, info.Name(), args)
 	defer func() {
 		if err != nil {
 			logrus.Infof("devmapper: Error while creating filesystem %s on device %s: %v", devices.filesystem, info.Name(), err)