rbd: add GetSnapGroupNamespace() to get details about group snapshots

rbd_snap_get_group_namespace() can be used to get details about
snapshots of an image, that were created as part of a group.

Signed-off-by: Niels de Vos <ndevos@ibm.com>

docs/api-status.json

@@ -1924,6 +1924,12 @@
         "comment": "Resize2 resizes an rbd image and allows configuration of allow_shrink and a callback function. The callback\nfunction will be called with the first argument as the progress, the second argument as the total, and the third\nargument as an opaque value that is passed to the Resize2 function's data argument in each callback execution.\nThe resize operation will be aborted if the progress callback returns a non-zero value.\n\nImplements:\n\n\tint rbd_resize2(rbd_image_t image, uint64_t size, allow_shrink bool, librbd_progress_fn_t cb, void *cbdata);\n",
         "added_in_version": "v0.25.0",
         "expected_stable_version": "v0.27.0"
+      },
+      {
+        "name": "Image.GetSnapGroupNamespace",
+        "comment": "GetSnapGroupNamespace returns the SnapGroupNamespace of the snapshot which\nis part of a group. The caller should make sure that the snapshot ID passed\nin this function belongs to a snapshot that was taken as part of a group\nsnapshot.\n\nImplements:\n\n\t\tint rbd_snap_get_group_namespace(rbd_image_t image, uint64_t snap_id,\n\t                                      rbd_snap_group_namespace_t *group_snap,\n\t                                      size_t group_snap_size)\n",
+        "added_in_version": "$NEXT_RELEASE",
+        "expected_stable_version": "$NEXT_RELEASE_STABLE"
       }
     ]
   },

docs/api-status.md

@@ -21,6 +21,7 @@ No Preview/Deprecated APIs found. All APIs are considered stable.
 Name | Added in Version | Expected Stable Version | 
 ---- | ---------------- | ----------------------- | 
 Image.Resize2 | v0.25.0 | v0.27.0 | 
+Image.GetSnapGroupNamespace | $NEXT_RELEASE | $NEXT_RELEASE_STABLE | 
 
 ### Deprecated APIs
 

rbd/snap_group_namespace.go

@@ -0,0 +1,53 @@
+//go:build ceph_preview
+
+package rbd
+
+// #cgo LDFLAGS: -lrbd
+// #include <rbd/librbd.h>
+import "C"
+
+// SnapGroupNamespace provides details about a single snapshot that was taken
+// as part of an RBD group.
+type SnapGroupNamespace struct {
+	Pool          uint64
+	GroupName     string
+	GroupSnapName string
+}
+
+// GetSnapGroupNamespace returns the SnapGroupNamespace of the snapshot which
+// is part of a group. The caller should make sure that the snapshot ID passed
+// in this function belongs to a snapshot that was taken as part of a group
+// snapshot.
+//
+// Implements:
+//
+//		int rbd_snap_get_group_namespace(rbd_image_t image, uint64_t snap_id,
+//	                                      rbd_snap_group_namespace_t *group_snap,
+//	                                      size_t group_snap_size)
+func (image *Image) GetSnapGroupNamespace(snapID uint64) (*SnapGroupNamespace, error) {
+	if err := image.validate(imageIsOpen); err != nil {
+		return nil, err
+	}
+
+	var (
+		err error
+		sgn C.rbd_snap_group_namespace_t
+	)
+
+	ret := C.rbd_snap_get_group_namespace(image.image,
+		C.uint64_t(snapID),
+		&sgn,
+		C.sizeof_rbd_snap_group_namespace_t)
+	err = getError(ret)
+	if err != nil {
+		return nil, err
+	}
+
+	defer C.rbd_snap_group_namespace_cleanup(&sgn, C.sizeof_rbd_snap_group_namespace_t)
+
+	return &SnapGroupNamespace{
+		Pool:          uint64(sgn.group_pool),
+		GroupName:     C.GoString(sgn.group_name),
+		GroupSnapName: C.GoString(sgn.group_snap_name),
+	}, nil
+}

rbd/snap_group_namespace_test.go

@@ -0,0 +1,95 @@
+//go:build ceph_preview
+
+package rbd
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestGetSnapGroupNamespace(t *testing.T) {
+	conn := radosConnect(t)
+	defer conn.Shutdown()
+
+	poolname := GetUUID()
+	err := conn.MakePool(poolname)
+	require.NoError(t, err)
+	defer conn.DeletePool(poolname)
+
+	ioctx, err := conn.OpenIOContext(poolname)
+	require.NoError(t, err)
+	defer ioctx.Destroy()
+
+	imageName := "parent"
+	groupName := "myGroup"
+	groupSnapName := "myGroupSnap"
+	options := NewRbdImageOptions()
+	defer options.Destroy()
+	err = options.SetUint64(ImageOptionOrder, uint64(testImageOrder))
+	assert.NoError(t, err)
+	err = options.SetUint64(ImageOptionFeatures, 1)
+	assert.NoError(t, err)
+
+	err = CreateImage(ioctx, imageName, testImageSize, options)
+	assert.NoError(t, err)
+
+	img, err := OpenImage(ioctx, imageName, NoSnapshot)
+	assert.NoError(t, err)
+	defer func() {
+		assert.NoError(t, img.Close())
+		assert.NoError(t, img.Remove())
+	}()
+
+	err = GroupCreate(ioctx, groupName)
+	require.NoError(t, err)
+	defer func() {
+		assert.NoError(t, GroupRemove(ioctx, groupName))
+	}()
+
+	err = GroupImageAdd(ioctx, groupName, ioctx, imageName)
+	require.NoError(t, err)
+	defer func() {
+		assert.NoError(t, GroupImageRemove(ioctx, groupName, ioctx, imageName))
+	}()
+
+	err = GroupSnapCreate(ioctx, groupName, groupSnapName)
+	require.NoError(t, err)
+	defer func() {
+		assert.NoError(t, GroupSnapRemove(ioctx, groupName, groupSnapName))
+	}()
+
+	// Take the details of the 1st snapshot of the image.
+	snapInfoList, err := img.GetSnapshotNames()
+	assert.NoError(t, err)
+	snapInfo := snapInfoList[0]
+	assert.Positive(t, snapInfo.Id)
+	assert.Regexp(t, "^\\.group\\.", snapInfo.Name)
+
+	// The snapshot is expected to be in the 'group' namespace.
+	nsType, err := img.GetSnapNamespaceType(snapInfo.Id)
+	assert.NoError(t, err)
+	assert.Equal(t, nsType, SnapNamespaceTypeGroup)
+
+	// Get the info from the snapshot in the group.
+	sgn, err := img.GetSnapGroupNamespace(snapInfo.Id)
+	assert.NoError(t, err)
+	require.NotNil(t, sgn)
+	assert.Equal(t, groupName, sgn.GroupName)
+
+	// Negative testing follows.
+	invalidSnapID := uint64(22)
+
+	t.Run("InvalidSnapID", func(t *testing.T) {
+		_, err := img.GetSnapGroupNamespace(invalidSnapID)
+		assert.Error(t, err)
+	})
+
+	t.Run("InvalidImage", func(t *testing.T) {
+		invalidImgName := GetUUID()
+		invalidImg := GetImage(ioctx, invalidImgName)
+		_, err := invalidImg.GetSnapGroupNamespace(invalidSnapID)
+		assert.Error(t, err)
+	})
+}