Functions to set hold, release and list user references on snapshots

a_test.go

@@ -25,6 +25,7 @@ func Test(t *testing.T) {
 	zfsTestDatasetSnapshot(t)
 	zfsTestDatasetOpenAll(t)
 	zfsTestDatasetSetProperty(t)
+	zfsTestDatasetHoldRelease(t)
 
 	zfsTestDatasetDestroy(t)
 

zfs.go

@@ -11,6 +11,7 @@ import (
 	"errors"
 	"fmt"
 	"strings"
+	"time"
 	"unsafe"
 )
 
@@ -37,6 +38,12 @@ const (
 	DatasetTypeBookmark = (1 << 4)
 )
 
+// HoldTag - user holds  tags
+type HoldTag struct {
+	Name      string
+	Timestamp time.Time
+}
+
 // Dataset - ZFS dataset object
 type Dataset struct {
 	list       C.dataset_list_ptr
@@ -99,6 +106,16 @@ func DatasetCloseAll(datasets []Dataset) {
 
 // DatasetOpen open dataset and all of its recursive children datasets
 func DatasetOpen(path string) (d Dataset, err error) {
+	if d, err = DatasetOpenSingle(path); err != nil {
+		return
+	}
+	err = d.openChildren()
+	return
+}
+
+// DatasetOpenSingle open dataset without opening all of its recursive
+// children datasets
+func DatasetOpenSingle(path string) (d Dataset, err error) {
 	csPath := C.CString(path)
 	d.list = C.dataset_open(csPath)
 	C.free(unsafe.Pointer(csPath))
@@ -117,7 +134,6 @@ func DatasetOpen(path string) (d Dataset, err error) {
 	if err != nil {
 		return
 	}
-	err = d.openChildren()
 	return
 }
 
@@ -201,6 +217,16 @@ func (d *Dataset) Destroy(Defer bool) (err error) {
 	return
 }
 
+// IsSnapshot - retrun true if datset is snapshot
+func (d *Dataset) IsSnapshot() (ok bool, err error) {
+	var path string
+	if path, err = d.Path(); err != nil {
+		return
+	}
+	ok = d.Type == DatasetTypeSnapshot || strings.Contains(path, "@")
+	return
+}
+
 // DestroyRecursive recursively destroy children of dataset and dataset.
 func (d *Dataset) DestroyRecursive() (err error) {
 	var path string
@@ -306,6 +332,7 @@ func (d *Dataset) GetProperty(p Prop) (prop Property, err error) {
 	return
 }
 
+// GetUserProperty - lookup and return user propery
 func (d *Dataset) GetUserProperty(p string) (prop Property, err error) {
 	if d.list == nil {
 		err = errors.New(msgDatasetIsNil)
@@ -345,6 +372,7 @@ func (d *Dataset) SetProperty(p Prop, value string) (err error) {
 	return
 }
 
+// SetUserProperty -
 func (d *Dataset) SetUserProperty(prop, value string) (err error) {
 	if d.list == nil {
 		err = errors.New(msgDatasetIsNil)
@@ -517,6 +545,93 @@ func (d *Dataset) UnmountAll(flags int) (err error) {
 	return d.Unmount(flags)
 }
 
+// Hold - Adds a single reference, named with the tag argument, to the snapshot.
+// Each snapshot has its own tag namespace, and tags must be unique within that space.
+func (d *Dataset) Hold(flag string) (err error) {
+	var path string
+	var pd Dataset
+	if path, err = d.Path(); err != nil {
+		return
+	}
+	if !strings.Contains(path, "@") {
+		err = fmt.Errorf("'%s' is not a snapshot", path)
+		return
+	}
+	pd, err = DatasetOpenSingle(path[:strings.Index(path, "@")])
+	if err != nil {
+		return
+	}
+	defer pd.Close()
+	csSnapName := C.CString(path[strings.Index(path, "@")+1:])
+	defer C.free(unsafe.Pointer(csSnapName))
+	csFlag := C.CString(flag)
+	defer C.free(unsafe.Pointer(csFlag))
+	if 0 != C.zfs_hold(pd.list.zh, csSnapName, csFlag, booleanT(false), -1) {
+		err = LastError()
+	}
+	return
+}
+
+// Release - Removes a single reference, named with the tag argument, from the specified snapshot.
+// The tag must already exist for each snapshot.  If a hold exists on a snapshot, attempts to destroy
+//  that snapshot by using the zfs destroy command return EBUSY.
+func (d *Dataset) Release(flag string) (err error) {
+	var path string
+	var pd Dataset
+	if path, err = d.Path(); err != nil {
+		return
+	}
+	if !strings.Contains(path, "@") {
+		err = fmt.Errorf("'%s' is not a snapshot", path)
+		return
+	}
+	pd, err = DatasetOpenSingle(path[:strings.Index(path, "@")])
+	if err != nil {
+		return
+	}
+	defer pd.Close()
+	csSnapName := C.CString(path[strings.Index(path, "@")+1:])
+	defer C.free(unsafe.Pointer(csSnapName))
+	csFlag := C.CString(flag)
+	defer C.free(unsafe.Pointer(csFlag))
+	if 0 != C.zfs_release(pd.list.zh, csSnapName, csFlag, booleanT(false)) {
+		err = LastError()
+	}
+	return
+}
+
+// Holds - Lists all existing user references for the given snapshot
+func (d *Dataset) Holds() (tags []HoldTag, err error) {
+	var nvl *C.nvlist_t
+	var nvp *C.nvpair_t
+	var tu64 C.uint64_t
+	var path string
+	if path, err = d.Path(); err != nil {
+		return
+	}
+	if !strings.Contains(path, "@") {
+		err = fmt.Errorf("'%s' is not a snapshot", path)
+		return
+	}
+	if 0 != C.zfs_get_holds(d.list.zh, &nvl) {
+		err = LastError()
+		return
+	}
+	defer C.nvlist_free(nvl)
+	tags = make([]HoldTag, 0, 5)
+	for nvp = C.nvlist_next_nvpair(nvl, nvp); nvp != nil; {
+		tag := C.nvpair_name(nvp)
+		C.nvpair_value_uint64(nvp, &tu64)
+		tags = append(tags, HoldTag{
+			Name:      C.GoString(tag),
+			Timestamp: time.Unix(int64(tu64), 0),
+		})
+
+		nvp = C.nvlist_next_nvpair(nvl, nvp)
+	}
+	return
+}
+
 // DatasetPropertyToName convert property to name
 // ( returns built in string representation of property name).
 // This is optional, you can represent each property with string

zfs_test.go

@@ -147,6 +147,47 @@ func zfsTestDatasetSnapshot(t *testing.T) {
 	print("PASS\n\n")
 }
 
+func zfsTestDatasetHoldRelease(t *testing.T) {
+	println("TEST Hold/Release(", TSTDatasetPathSnap, ", true, ...) ... ")
+	d, err := zfs.DatasetOpen(TSTDatasetPathSnap)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	defer d.Close()
+	err = d.Hold("keep")
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	var tags []zfs.HoldTag
+	tags, err = d.Holds()
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	for _, tag := range tags {
+		println("tag:", tag.Name, "timestamp:", tag.Timestamp.String())
+	}
+
+	err = d.Release("keep")
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	tags, err = d.Holds()
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	for _, tag := range tags {
+		println("* tag:", tag.Name, "timestamp:", tag.Timestamp.String())
+	}
+	print("PASS\n\n")
+}
+
 func zfsTestDatasetDestroy(t *testing.T) {
 	println("TEST DATASET Destroy( ", TSTDatasetPath, " ) ... ")
 	d, err := zfs.DatasetOpen(TSTDatasetPath)

zpool_test.go

@@ -1,7 +1,6 @@
 package zfs_test
 
 import (
-	"encoding/json"
 	"fmt"
 	"io/ioutil"
 	"os"
@@ -531,33 +530,33 @@ func ExamplePool_State() {
 	println("POOL TESTPOOL state:", zfs.PoolStateToName(pstate))
 }
 
-func TestPool_VDevTree(t *testing.T) {
-	type fields struct {
-		poolName string
-	}
-	tests := []struct {
-		name    string
-		fields  fields
-		wantErr bool
-	}{
-		// TODO: Add test cases.
-		{
-			name:    "test1",
-			fields:  fields{"TESTPOOL"},
-			wantErr: false,
-		},
-	}
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			pool, _ := zfs.PoolOpen(tt.fields.poolName)
-			defer pool.Close()
-			gotVdevs, err := pool.VDevTree()
-			if (err != nil) != tt.wantErr {
-				t.Errorf("Pool.VDevTree() error = %v, wantErr %v", err, tt.wantErr)
-				return
-			}
-			jsonData, _ := json.MarshalIndent(gotVdevs, "", "\t")
-			t.Logf("gotVdevs: %s", string(jsonData))
-		})
-	}
-}
+// func TestPool_VDevTree(t *testing.T) {
+// 	type fields struct {
+// 		poolName string
+// 	}
+// 	tests := []struct {
+// 		name    string
+// 		fields  fields
+// 		wantErr bool
+// 	}{
+// 		// TODO: Add test cases.
+// 		{
+// 			name:    "test1",
+// 			fields:  fields{"TESTPOOL"},
+// 			wantErr: false,
+// 		},
+// 	}
+// 	for _, tt := range tests {
+// 		t.Run(tt.name, func(t *testing.T) {
+// 			pool, _ := zfs.PoolOpen(tt.fields.poolName)
+// 			defer pool.Close()
+// 			gotVdevs, err := pool.VDevTree()
+// 			if (err != nil) != tt.wantErr {
+// 				t.Errorf("Pool.VDevTree() error = %v, wantErr %v", err, tt.wantErr)
+// 				return
+// 			}
+// 			jsonData, _ := json.MarshalIndent(gotVdevs, "", "\t")
+// 			t.Logf("gotVdevs: %s", string(jsonData))
+// 		})
+// 	}
+// }