Merge pull request #18651 from vbatts/dm-cleanup

loopback (and devicemapper) cleanup

daemon/graphdriver/devmapper/deviceset.go

@@ -24,6 +24,7 @@ import (
 	"github.com/docker/docker/daemon/graphdriver"
 	"github.com/docker/docker/pkg/devicemapper"
 	"github.com/docker/docker/pkg/idtools"
+	"github.com/docker/docker/pkg/loopback"
 	"github.com/docker/docker/pkg/mount"
 	"github.com/docker/docker/pkg/parsers"
 	"github.com/docker/go-units"
@@ -1170,7 +1171,7 @@ func (devices *DeviceSet) ResizePool(size int64) error {
 		return fmt.Errorf("devmapper: Can't shrink file")
 	}
 
-	dataloopback := devicemapper.FindLoopDeviceFor(datafile)
+	dataloopback := loopback.FindLoopDeviceFor(datafile)
 	if dataloopback == nil {
 		return fmt.Errorf("devmapper: Unable to find loopback mount for: %s", datafilename)
 	}
@@ -1182,7 +1183,7 @@ func (devices *DeviceSet) ResizePool(size int64) error {
 	}
 	defer metadatafile.Close()
 
-	metadataloopback := devicemapper.FindLoopDeviceFor(metadatafile)
+	metadataloopback := loopback.FindLoopDeviceFor(metadatafile)
 	if metadataloopback == nil {
 		return fmt.Errorf("devmapper: Unable to find loopback mount for: %s", metadatafilename)
 	}
@@ -1194,8 +1195,8 @@ func (devices *DeviceSet) ResizePool(size int64) error {
 	}
 
 	// Reload size for loopback device
-	if err := devicemapper.LoopbackSetCapacity(dataloopback); err != nil {
+	if err := loopback.SetCapacity(dataloopback); err != nil {
-		return fmt.Errorf("devmapper: Unable to update loopback capacity: %s", err)
+		return fmt.Errorf("Unable to update loopback capacity: %s", err)
 	}
 
 	// Suspend the pool
@@ -1414,7 +1415,7 @@ func getLoopFileDeviceMajMin(filename string) (string, uint64, uint64, error) {
 	}
 
 	defer file.Close()
-	loopbackDevice := devicemapper.FindLoopDeviceFor(file)
+	loopbackDevice := loopback.FindLoopDeviceFor(file)
 	if loopbackDevice == nil {
 		return "", 0, 0, fmt.Errorf("devmapper: Unable to find loopback mount for: %s", filename)
 	}
@@ -1622,7 +1623,7 @@ func (devices *DeviceSet) initDevmapper(doInit bool) error {
 				return err
 			}
 
-			dataFile, err = devicemapper.AttachLoopDevice(data)
+			dataFile, err = loopback.AttachLoopDevice(data)
 			if err != nil {
 				return err
 			}
@@ -1655,7 +1656,7 @@ func (devices *DeviceSet) initDevmapper(doInit bool) error {
 				return err
 			}
 
-			metadataFile, err = devicemapper.AttachLoopDevice(metadata)
+			metadataFile, err = loopback.AttachLoopDevice(metadata)
 			if err != nil {
 				return err
 			}

pkg/devicemapper/devmapper.go

@@ -60,7 +60,6 @@ var (
 	ErrTaskDeferredRemove   = errors.New("dm_task_deferred_remove failed")
 	ErrTaskSetCookie        = errors.New("dm_task_set_cookie failed")
 	ErrNilCookie            = errors.New("cookie ptr can't be nil")
-	ErrAttachLoopbackDevice   = errors.New("loopback mounting failed")
 	ErrGetBlockSize         = errors.New("Can't get block size")
 	ErrUdevWait             = errors.New("wait on udev cookie failed")
 	ErrSetDevDir            = errors.New("dm_set_dev_dir failed")
@@ -68,8 +67,6 @@ var (
 	ErrCreateRemoveTask     = errors.New("Can't create task of type deviceRemove")
 	ErrRunRemoveDevice      = errors.New("running RemoveDevice failed")
 	ErrInvalidAddNode       = errors.New("Invalid AddNode type")
-	ErrGetLoopbackBackingFile = errors.New("Unable to get loopback backing file")
-	ErrLoopbackSetCapacity    = errors.New("Unable set loopback capacity")
 	ErrBusy                 = errors.New("Device is Busy")
 	ErrDeviceIDExists       = errors.New("Device Id Exists")
 	ErrEnxio                = errors.New("No such device or address")
@@ -257,58 +254,6 @@ func (t *Task) getNextTarget(next unsafe.Pointer) (nextPtr unsafe.Pointer, start
 		start, length, targetType, params
 }
 
-func getLoopbackBackingFile(file *os.File) (uint64, uint64, error) {
-	loopInfo, err := ioctlLoopGetStatus64(file.Fd())
-	if err != nil {
-		logrus.Errorf("devicemapper: Error get loopback backing file: %s", err)
-		return 0, 0, ErrGetLoopbackBackingFile
-	}
-	return loopInfo.loDevice, loopInfo.loInode, nil
-}
-
-// LoopbackSetCapacity reloads the size for the loopback device.
-func LoopbackSetCapacity(file *os.File) error {
-	if err := ioctlLoopSetCapacity(file.Fd(), 0); err != nil {
-		logrus.Errorf("devicemapper: Error loopbackSetCapacity: %s", err)
-		return ErrLoopbackSetCapacity
-	}
-	return nil
-}
-
-// FindLoopDeviceFor returns a loopback device file for the specified file which
-// is backing file of a loop back device.
-func FindLoopDeviceFor(file *os.File) *os.File {
-	stat, err := file.Stat()
-	if err != nil {
-		return nil
-	}
-	targetInode := stat.Sys().(*syscall.Stat_t).Ino
-	targetDevice := stat.Sys().(*syscall.Stat_t).Dev
-
-	for i := 0; true; i++ {
-		path := fmt.Sprintf("/dev/loop%d", i)
-
-		file, err := os.OpenFile(path, os.O_RDWR, 0)
-		if err != nil {
-			if os.IsNotExist(err) {
-				return nil
-			}
-
-			// Ignore all errors until the first not-exist
-			// we want to continue looking for the file
-			continue
-		}
-
-		dev, inode, err := getLoopbackBackingFile(file)
-		if err == nil && dev == targetDevice && inode == targetInode {
-			return file
-		}
-		file.Close()
-	}
-
-	return nil
-}
-
 // UdevWait waits for any processes that are waiting for udev to complete the specified cookie.
 func UdevWait(cookie *uint) error {
 	if res := DmUdevWait(*cookie); res != 1 {

pkg/devicemapper/devmapper_wrapper.go

@@ -5,17 +5,8 @@ package devicemapper
 /*
 #cgo LDFLAGS: -L. -ldevmapper
 #include <libdevmapper.h>
-#include <linux/loop.h> // FIXME: present only for defines, maybe we can remove it?
 #include <linux/fs.h>   // FIXME: present only for BLKGETSIZE64, maybe we can remove it?
 
-#ifndef LOOP_CTL_GET_FREE
-  #define LOOP_CTL_GET_FREE 0x4C82
-#endif
-
-#ifndef LO_FLAGS_PARTSCAN
-  #define LO_FLAGS_PARTSCAN 8
-#endif
-
 // FIXME: Can't we find a way to do the logging in pure Go?
 extern void DevmapperLogCallback(int level, char *file, int line, int dm_errno_or_class, char *str);
 
@@ -45,45 +36,12 @@ import (
 
 type (
 	cdmTask C.struct_dm_task
-
-	cLoopInfo64 C.struct_loop_info64
-	loopInfo64  struct {
-		loDevice         uint64 /* ioctl r/o */
-		loInode          uint64 /* ioctl r/o */
-		loRdevice        uint64 /* ioctl r/o */
-		loOffset         uint64
-		loSizelimit      uint64 /* bytes, 0 == max available */
-		loNumber         uint32 /* ioctl r/o */
-		loEncryptType    uint32
-		loEncryptKeySize uint32 /* ioctl w/o */
-		loFlags          uint32 /* ioctl r/o */
-		loFileName       [LoNameSize]uint8
-		loCryptName      [LoNameSize]uint8
-		loEncryptKey     [LoKeySize]uint8 /* ioctl w/o */
-		loInit           [2]uint64
-	}
 )
 
 // IOCTL consts
 const (
 	BlkGetSize64 = C.BLKGETSIZE64
 	BlkDiscard   = C.BLKDISCARD
-
-	LoopSetFd       = C.LOOP_SET_FD
-	LoopCtlGetFree  = C.LOOP_CTL_GET_FREE
-	LoopGetStatus64 = C.LOOP_GET_STATUS64
-	LoopSetStatus64 = C.LOOP_SET_STATUS64
-	LoopClrFd       = C.LOOP_CLR_FD
-	LoopSetCapacity = C.LOOP_SET_CAPACITY
-)
-
-// LOOP consts.
-const (
-	LoFlagsAutoClear = C.LO_FLAGS_AUTOCLEAR
-	LoFlagsReadOnly  = C.LO_FLAGS_READ_ONLY
-	LoFlagsPartScan  = C.LO_FLAGS_PARTSCAN
-	LoKeySize        = C.LO_KEY_SIZE
-	LoNameSize       = C.LO_NAME_SIZE
 )
 
 // Devicemapper cookie flags.

pkg/devicemapper/ioctl.go

@@ -7,51 +7,6 @@ import (
 	"unsafe"
 )
 
-func ioctlLoopCtlGetFree(fd uintptr) (int, error) {
-	index, _, err := syscall.Syscall(syscall.SYS_IOCTL, fd, LoopCtlGetFree, 0)
-	if err != 0 {
-		return 0, err
-	}
-	return int(index), nil
-}
-
-func ioctlLoopSetFd(loopFd, sparseFd uintptr) error {
-	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, loopFd, LoopSetFd, sparseFd); err != 0 {
-		return err
-	}
-	return nil
-}
-
-func ioctlLoopSetStatus64(loopFd uintptr, loopInfo *loopInfo64) error {
-	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, loopFd, LoopSetStatus64, uintptr(unsafe.Pointer(loopInfo))); err != 0 {
-		return err
-	}
-	return nil
-}
-
-func ioctlLoopClrFd(loopFd uintptr) error {
-	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, loopFd, LoopClrFd, 0); err != 0 {
-		return err
-	}
-	return nil
-}
-
-func ioctlLoopGetStatus64(loopFd uintptr) (*loopInfo64, error) {
-	loopInfo := &loopInfo64{}
-
-	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, loopFd, LoopGetStatus64, uintptr(unsafe.Pointer(loopInfo))); err != 0 {
-		return nil, err
-	}
-	return loopInfo, nil
-}
-
-func ioctlLoopSetCapacity(loopFd uintptr, value int) error {
-	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, loopFd, LoopSetCapacity, uintptr(value)); err != 0 {
-		return err
-	}
-	return nil
-}
-
 func ioctlBlkGetSize64(fd uintptr) (int64, error) {
 	var size int64
 	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, fd, BlkGetSize64, uintptr(unsafe.Pointer(&size))); err != 0 {

pkg/loopback/attach_loopback.go

@@ -1,8 +1,9 @@
 // +build linux
 
-package devicemapper
+package loopback
 
 import (
+	"errors"
 	"fmt"
 	"os"
 	"syscall"
@@ -10,6 +11,13 @@ import (
 	"github.com/Sirupsen/logrus"
 )
 
+// Loopback related errors
+var (
+	ErrAttachLoopbackDevice   = errors.New("loopback attach failed")
+	ErrGetLoopbackBackingFile = errors.New("Unable to get loopback backing file")
+	ErrSetCapacity            = errors.New("Unable set loopback capacity")
+)
+
 func stringToLoopName(src string) [LoNameSize]uint8 {
 	var dst [LoNameSize]uint8
 	copy(dst[:], src[:])

pkg/loopback/ioctl.go

@@ -0,0 +1,53 @@
+// +build linux
+
+package loopback
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+func ioctlLoopCtlGetFree(fd uintptr) (int, error) {
+	index, _, err := syscall.Syscall(syscall.SYS_IOCTL, fd, LoopCtlGetFree, 0)
+	if err != 0 {
+		return 0, err
+	}
+	return int(index), nil
+}
+
+func ioctlLoopSetFd(loopFd, sparseFd uintptr) error {
+	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, loopFd, LoopSetFd, sparseFd); err != 0 {
+		return err
+	}
+	return nil
+}
+
+func ioctlLoopSetStatus64(loopFd uintptr, loopInfo *loopInfo64) error {
+	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, loopFd, LoopSetStatus64, uintptr(unsafe.Pointer(loopInfo))); err != 0 {
+		return err
+	}
+	return nil
+}
+
+func ioctlLoopClrFd(loopFd uintptr) error {
+	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, loopFd, LoopClrFd, 0); err != 0 {
+		return err
+	}
+	return nil
+}
+
+func ioctlLoopGetStatus64(loopFd uintptr) (*loopInfo64, error) {
+	loopInfo := &loopInfo64{}
+
+	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, loopFd, LoopGetStatus64, uintptr(unsafe.Pointer(loopInfo))); err != 0 {
+		return nil, err
+	}
+	return loopInfo, nil
+}
+
+func ioctlLoopSetCapacity(loopFd uintptr, value int) error {
+	if _, _, err := syscall.Syscall(syscall.SYS_IOCTL, loopFd, LoopSetCapacity, uintptr(value)); err != 0 {
+		return err
+	}
+	return nil
+}

pkg/loopback/loop_wrapper.go

@@ -0,0 +1,52 @@
+// +build linux
+
+package loopback
+
+/*
+#include <linux/loop.h> // FIXME: present only for defines, maybe we can remove it?
+
+#ifndef LOOP_CTL_GET_FREE
+  #define LOOP_CTL_GET_FREE 0x4C82
+#endif
+
+#ifndef LO_FLAGS_PARTSCAN
+  #define LO_FLAGS_PARTSCAN 8
+#endif
+
+*/
+import "C"
+
+type loopInfo64 struct {
+	loDevice         uint64 /* ioctl r/o */
+	loInode          uint64 /* ioctl r/o */
+	loRdevice        uint64 /* ioctl r/o */
+	loOffset         uint64
+	loSizelimit      uint64 /* bytes, 0 == max available */
+	loNumber         uint32 /* ioctl r/o */
+	loEncryptType    uint32
+	loEncryptKeySize uint32 /* ioctl w/o */
+	loFlags          uint32 /* ioctl r/o */
+	loFileName       [LoNameSize]uint8
+	loCryptName      [LoNameSize]uint8
+	loEncryptKey     [LoKeySize]uint8 /* ioctl w/o */
+	loInit           [2]uint64
+}
+
+// IOCTL consts
+const (
+	LoopSetFd       = C.LOOP_SET_FD
+	LoopCtlGetFree  = C.LOOP_CTL_GET_FREE
+	LoopGetStatus64 = C.LOOP_GET_STATUS64
+	LoopSetStatus64 = C.LOOP_SET_STATUS64
+	LoopClrFd       = C.LOOP_CLR_FD
+	LoopSetCapacity = C.LOOP_SET_CAPACITY
+)
+
+// LOOP consts.
+const (
+	LoFlagsAutoClear = C.LO_FLAGS_AUTOCLEAR
+	LoFlagsReadOnly  = C.LO_FLAGS_READ_ONLY
+	LoFlagsPartScan  = C.LO_FLAGS_PARTSCAN
+	LoKeySize        = C.LO_KEY_SIZE
+	LoNameSize       = C.LO_NAME_SIZE
+)

pkg/loopback/loopback.go

@@ -0,0 +1,63 @@
+// +build linux
+
+package loopback
+
+import (
+	"fmt"
+	"os"
+	"syscall"
+
+	"github.com/Sirupsen/logrus"
+)
+
+func getLoopbackBackingFile(file *os.File) (uint64, uint64, error) {
+	loopInfo, err := ioctlLoopGetStatus64(file.Fd())
+	if err != nil {
+		logrus.Errorf("Error get loopback backing file: %s", err)
+		return 0, 0, ErrGetLoopbackBackingFile
+	}
+	return loopInfo.loDevice, loopInfo.loInode, nil
+}
+
+// SetCapacity reloads the size for the loopback device.
+func SetCapacity(file *os.File) error {
+	if err := ioctlLoopSetCapacity(file.Fd(), 0); err != nil {
+		logrus.Errorf("Error loopbackSetCapacity: %s", err)
+		return ErrSetCapacity
+	}
+	return nil
+}
+
+// FindLoopDeviceFor returns a loopback device file for the specified file which
+// is backing file of a loop back device.
+func FindLoopDeviceFor(file *os.File) *os.File {
+	stat, err := file.Stat()
+	if err != nil {
+		return nil
+	}
+	targetInode := stat.Sys().(*syscall.Stat_t).Ino
+	targetDevice := stat.Sys().(*syscall.Stat_t).Dev
+
+	for i := 0; true; i++ {
+		path := fmt.Sprintf("/dev/loop%d", i)
+
+		file, err := os.OpenFile(path, os.O_RDWR, 0)
+		if err != nil {
+			if os.IsNotExist(err) {
+				return nil
+			}
+
+			// Ignore all errors until the first not-exist
+			// we want to continue looking for the file
+			continue
+		}
+
+		dev, inode, err := getLoopbackBackingFile(file)
+		if err == nil && dev == targetDevice && inode == targetInode {
+			return file
+		}
+		file.Close()
+	}
+
+	return nil
+}