@@ -353,6 +353,9 @@ func AttachLoopDevice(filename string) (*os.File, error) {

 	var fd C.int

 	res := C.attach_loop_device(c_filename, &fd)

 	if res == nil {

+		if os.Getenv("DEBUG") != "" {

+			C.perror(C.CString(fmt.Sprintf("[debug] Error attach_loop_device(%s, $#v)", c_filename, &fd)))

+		}

 		return nil, ErrAttachLoopbackDevice

 	}

 	defer free(res)

@@ -1,6 +1,7 @@

 package docker

 import (

+	"path"

 	"bytes"

 	"fmt"

 	"github.com/dotcloud/docker/devmapper"

@@ -107,12 +108,15 @@ func removeDev(name string) error {

 }

 func cleanupDevMapper() error {

+	filter := "docker-" + path.Base(unitTestStoreBase)

+	utils.Debugf("Filtering out %s\n", filter)

 	// Unmount any leftover mounts from previous unit test runs

 	if data, err := ioutil.ReadFile("/proc/mounts"); err != nil {

 		return err

 	} else {

 		for _, line := range strings.Split(string(data), "\n") {

-			if cols := strings.Split(line, " "); len(cols) >= 2 && strings.HasPrefix(cols[0], "/dev/mapper/docker-unit-tests-devices") {

+			if cols := strings.Split(line, " "); len(cols) >= 2 && strings.HasPrefix(cols[0], path.Join("/dev/mapper", filter)) {

+				utils.Debugf("[devmapper cleanup] Unmounting device: %s", cols[1])

 				if err := syscall.Unmount(cols[1], 0); err != nil {

 					return fmt.Errorf("Unable to unmount %s needed to get a freash unit test environment: %s", cols[1], err)

 				}

@@ -120,6 +124,7 @@ func cleanupDevMapper() error {

 		}

 	}

+	utils.Debugf("[devmapper cleanup] looking for leftover devices")

 	// Remove any leftover devmapper devices from previous unit run tests

 	infos, err := ioutil.ReadDir("/dev/mapper")

 	if err != nil {

@@ -131,8 +136,8 @@ func cleanupDevMapper() error {

 	}

 	pools := []string{}

 	for _, info := range infos {

-		if name := info.Name(); strings.HasPrefix(name, "docker-unit-tests-devices-") {

-			if name == "docker-unit-tests-devices-pool" {

+		if name := info.Name(); strings.HasPrefix(name, filter + "-") {

+			if strings.HasSuffix(name, "-pool") {

 				pools = append(pools, name)

 			} else {

 				if err := removeDev(name); err != nil {

@@ -143,6 +148,7 @@ func cleanupDevMapper() error {

 	}

 	// We need to remove the pool last as the other devices block it

 	for _, pool := range pools {

+		utils.Debugf("[devmapper cleanup] Removing pool: %s", pool)

 		if err := removeDev(pool); err != nil {

 			return err

 		}