Merge pull request #12190 from rhvgoyal/deferred-removal

Devicemapper: Provide deferred device removal capability

devicemapper/devmapper.go

@@ -55,6 +55,7 @@ var (
 	ErrTaskGetDeps            = errors.New("dm_task_get_deps failed")
 	ErrTaskGetInfo            = errors.New("dm_task_get_info failed")
 	ErrTaskGetDriverVersion   = errors.New("dm_task_get_driver_version failed")
+	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")
@@ -69,9 +70,11 @@ var (
 	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")
 
 	dmSawBusy  bool
 	dmSawExist bool
+	dmSawEnxio bool // No Such Device or Address
 )
 
 type (
@@ -94,6 +97,7 @@ type (
 		Minor          uint32
 		ReadOnly       int
 		TargetCount    int32
+		DeferredRemove int
 	}
 	TaskType    int
 	AddNodeType int
@@ -219,6 +223,14 @@ func (t *Task) GetInfo() (*Info, error) {
 	return info, nil
 }
 
+func (t *Task) GetInfoWithDeferred() (*Info, error) {
+	info := &Info{}
+	if res := DmTaskGetInfoWithDeferred(t.unmanaged, info); res != 1 {
+		return nil, ErrTaskGetInfo
+	}
+	return info, nil
+}
+
 func (t *Task) GetDriverVersion() (string, error) {
 	res := DmTaskGetDriverVersion(t.unmanaged)
 	if res == "" {
@@ -371,6 +383,55 @@ func RemoveDevice(name string) error {
 	return nil
 }
 
+func RemoveDeviceDeferred(name string) error {
+	logrus.Debugf("[devmapper] RemoveDeviceDeferred START(%s)", name)
+	defer logrus.Debugf("[devmapper] RemoveDeviceDeferred END(%s)", name)
+	task, err := TaskCreateNamed(DeviceRemove, name)
+	if task == nil {
+		return err
+	}
+
+	if err := DmTaskDeferredRemove(task.unmanaged); err != 1 {
+		return ErrTaskDeferredRemove
+	}
+
+	if err = task.Run(); err != nil {
+		return fmt.Errorf("Error running RemoveDeviceDeferred %s", err)
+	}
+
+	return nil
+}
+
+// Useful helper for cleanup
+func CancelDeferredRemove(deviceName string) error {
+	task, err := TaskCreateNamed(DeviceTargetMsg, deviceName)
+	if task == nil {
+		return err
+	}
+
+	if err := task.SetSector(0); err != nil {
+		return fmt.Errorf("Can't set sector %s", err)
+	}
+
+	if err := task.SetMessage(fmt.Sprintf("@cancel_deferred_remove")); err != nil {
+		return fmt.Errorf("Can't set message %s", err)
+	}
+
+	dmSawBusy = false
+	dmSawEnxio = false
+	if err := task.Run(); err != nil {
+		// A device might be being deleted already
+		if dmSawBusy {
+			return ErrBusy
+		} else if dmSawEnxio {
+			return ErrEnxio
+		}
+		return fmt.Errorf("Error running CancelDeferredRemove %s", err)
+
+	}
+	return nil
+}
+
 func GetBlockDeviceSize(file *os.File) (uint64, error) {
 	size, err := ioctlBlkGetSize64(file.Fd())
 	if err != nil {
@@ -479,6 +540,17 @@ func GetInfo(name string) (*Info, error) {
 	return task.GetInfo()
 }
 
+func GetInfoWithDeferred(name string) (*Info, error) {
+	task, err := TaskCreateNamed(DeviceInfo, name)
+	if task == nil {
+		return nil, err
+	}
+	if err := task.Run(); err != nil {
+		return nil, err
+	}
+	return task.GetInfoWithDeferred()
+}
+
 func GetDriverVersion() (string, error) {
 	task := TaskCreate(DeviceVersion)
 	if task == nil {

devicemapper/devmapper_log.go

@@ -22,6 +22,10 @@ func DevmapperLogCallback(level C.int, file *C.char, line C.int, dm_errno_or_cla
 		if strings.Contains(msg, "File exists") {
 			dmSawExist = true
 		}
+
+		if strings.Contains(msg, "No such device or address") {
+			dmSawEnxio = true
+		}
 	}
 
 	if dmLogger != nil {

devicemapper/devmapper_wrapper.go

@@ -112,6 +112,8 @@ var (
 	DmUdevGetSyncSupport      = dmUdevGetSyncSupportFct
 	DmCookieSupported         = dmCookieSupportedFct
 	LogWithErrnoInit          = logWithErrnoInitFct
+	DmTaskDeferredRemove      = dmTaskDeferredRemoveFct
+	DmTaskGetInfoWithDeferred = dmTaskGetInfoWithDeferredFct
 )
 
 func free(p *C.char) {

devicemapper/devmapper_wrapper_deferred_remove.go

@@ -0,0 +1,33 @@
+// +build linux,!libdm_no_deferred_remove
+
+package devicemapper
+
+/*
+#cgo LDFLAGS: -L. -ldevmapper
+#include <libdevmapper.h>
+*/
+import "C"
+
+const LibraryDeferredRemovalSupport = true
+
+func dmTaskDeferredRemoveFct(task *CDmTask) int {
+	return int(C.dm_task_deferred_remove((*C.struct_dm_task)(task)))
+}
+
+func dmTaskGetInfoWithDeferredFct(task *CDmTask, info *Info) int {
+	Cinfo := C.struct_dm_info{}
+	defer func() {
+		info.Exists = int(Cinfo.exists)
+		info.Suspended = int(Cinfo.suspended)
+		info.LiveTable = int(Cinfo.live_table)
+		info.InactiveTable = int(Cinfo.inactive_table)
+		info.OpenCount = int32(Cinfo.open_count)
+		info.EventNr = uint32(Cinfo.event_nr)
+		info.Major = uint32(Cinfo.major)
+		info.Minor = uint32(Cinfo.minor)
+		info.ReadOnly = int(Cinfo.read_only)
+		info.TargetCount = int32(Cinfo.target_count)
+		info.DeferredRemove = int(Cinfo.deferred_remove)
+	}()
+	return int(C.dm_task_get_info((*C.struct_dm_task)(task), &Cinfo))
+}

devicemapper/devmapper_wrapper_no_deferred_remove.go

@@ -0,0 +1,14 @@
+// +build linux,libdm_no_deferred_remove
+
+package devicemapper
+
+const LibraryDeferredRemovalSupport = false
+
+func dmTaskDeferredRemoveFct(task *CDmTask) int {
+	// Error. Nobody should be calling it.
+	return -1
+}
+
+func dmTaskGetInfoWithDeferredFct(task *CDmTask, info *Info) int {
+	return -1
+}