devicemapper: Create a method to get device info with deferred remove field

Deferred reove functionality was added to library later. So in old version
of library it did not report deferred_remove field. 

Create a new function which also gets deferred_remove field and it will be
called only on newer version of library. 

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>

devicemapper/devmapper.go

@@ -97,6 +97,7 @@ type (
 		Minor          uint32
 		ReadOnly       int
 		TargetCount    int32
+		DeferredRemove int
 	}
 	TaskType    int
 	AddNodeType int
@@ -222,6 +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 == "" {
@@ -531,6 +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_wrapper.go

@@ -113,6 +113,7 @@ var (
 	DmCookieSupported         = dmCookieSupportedFct
 	LogWithErrnoInit          = logWithErrnoInitFct
 	DmTaskDeferredRemove      = dmTaskDeferredRemoveFct
+	DmTaskGetInfoWithDeferred = dmTaskGetInfoWithDeferredFct
 )
 
 func free(p *C.char) {

devicemapper/devmapper_wrapper_deferred_remove.go

@@ -13,3 +13,21 @@ 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

@@ -8,3 +8,7 @@ func dmTaskDeferredRemoveFct(task *CDmTask) int {
 	// Error. Nobody should be calling it.
 	return -1
 }
+
+func dmTaskGetInfoWithDeferredFct(task *CDmTask, info *Info) int {
+	return -1
+}