rbd: add support for CloneImageByID()

RBD image groups can be used to create consistent snapshots of all
images that are part of the group. The new rbd_clone4() API makes it
possible to create a new RBD image from a single snapshot that was
created as part of the group snapshot.

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

docs/api-status.json

@@ -1956,6 +1956,12 @@
         "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": "v0.27.0",
         "expected_stable_version": "v0.29.0"
+      },
+      {
+        "name": "CloneImageByID",
+        "comment": "CloneImageByID creates a clone of the image from a snapshot with the given\nID in the provided io-context with the given name and image options.\n\nImplements:\n\n\tint rbd_clone4(rados_ioctx_t p_ioctx, const char *p_name,\n\t               uint64_t p_snap_id, rados_ioctx_t c_ioctx,\n\t               const char *c_name, rbd_image_options_t c_opts);\n",
+        "added_in_version": "$NEXT_RELEASE",
+        "expected_stable_version": "$NEXT_RELEASE_STABLE"
       }
     ]
   },
@@ -2259,4 +2265,4 @@
       }
     ]
   }
-}
+}

docs/api-status.md

@@ -31,6 +31,7 @@ WriteOp.Exec | $NEXT_RELEASE | $NEXT_RELEASE_STABLE |
 Name | Added in Version | Expected Stable Version | 
 ---- | ---------------- | ----------------------- | 
 Image.GetSnapGroupNamespace | v0.27.0 | v0.29.0 | 
+CloneImageByID | $NEXT_RELEASE | $NEXT_RELEASE_STABLE | 
 
 ### Deprecated APIs
 

rbd/clone_image_by_id.go

@@ -0,0 +1,46 @@
+//go:build !(nautilus || octopus || pacific || quincy || reef) && ceph_preview
+
+package rbd
+
+// #cgo LDFLAGS: -lrbd
+// #include <errno.h>
+// #include <stdlib.h>
+// #include <rados/librados.h>
+// #include <rbd/librbd.h>
+import "C"
+
+import (
+	"unsafe"
+
+	"github.com/ceph/go-ceph/rados"
+)
+
+// CloneImageByID creates a clone of the image from a snapshot with the given
+// ID in the provided io-context with the given name and image options.
+//
+// Implements:
+//
+//	int rbd_clone4(rados_ioctx_t p_ioctx, const char *p_name,
+//	               uint64_t p_snap_id, rados_ioctx_t c_ioctx,
+//	               const char *c_name, rbd_image_options_t c_opts);
+func CloneImageByID(ioctx *rados.IOContext, parentName string, snapID uint64,
+	destctx *rados.IOContext, name string, rio *ImageOptions) error {
+
+	if rio == nil {
+		return rbdError(C.EINVAL)
+	}
+
+	cParentName := C.CString(parentName)
+	defer C.free(unsafe.Pointer(cParentName))
+	cCloneName := C.CString(name)
+	defer C.free(unsafe.Pointer(cCloneName))
+
+	ret := C.rbd_clone4(
+		cephIoctx(ioctx),
+		cParentName,
+		C.uint64_t(snapID),
+		cephIoctx(destctx),
+		cCloneName,
+		C.rbd_image_options_t(rio.options))
+	return getError(ret)
+}

rbd/clone_image_by_id_test.go

@@ -0,0 +1,154 @@
+//go:build !(nautilus || octopus || pacific || quincy || reef) && ceph_preview
+
+package rbd
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestCloneImageByID(t *testing.T) {
+	// tests are done as subtests to avoid creating pools, images, etc
+	// over and over again.
+	conn := radosConnect(t)
+	require.NotNil(t, conn)
+	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()
+
+	// create a group, some images, and add images to the group
+	gname := "snapme"
+	err = GroupCreate(ioctx, gname)
+	assert.NoError(t, err)
+	defer func() {
+		assert.NoError(t, GroupRemove(ioctx, gname))
+	}()
+
+	options := NewRbdImageOptions()
+	assert.NoError(t,
+		options.SetUint64(ImageOptionOrder, uint64(testImageOrder)))
+	defer options.Destroy()
+
+	name1 := GetUUID()
+	err = CreateImage(ioctx, name1, testImageSize, options)
+	require.NoError(t, err)
+	defer func() {
+		assert.NoError(t, RemoveImage(ioctx, name1))
+	}()
+
+	name2 := GetUUID()
+	err = CreateImage(ioctx, name2, testImageSize, options)
+	require.NoError(t, err)
+	defer func() {
+		assert.NoError(t, RemoveImage(ioctx, name2))
+	}()
+
+	err = GroupImageAdd(ioctx, gname, ioctx, name1)
+	assert.NoError(t, err)
+	defer func() {
+		assert.NoError(t, GroupImageRemove(ioctx, gname, ioctx, name1))
+	}()
+
+	err = GroupImageAdd(ioctx, gname, ioctx, name2)
+	assert.NoError(t, err)
+	defer func() {
+		assert.NoError(t, GroupImageRemove(ioctx, gname, ioctx, name2))
+	}()
+
+	t.Run("CloneFromSnapshot", func(t *testing.T) {
+		cloneName := "child"
+		optionsClone := NewRbdImageOptions()
+		defer optionsClone.Destroy()
+		err := optionsClone.SetUint64(ImageOptionCloneFormat, 2)
+		assert.NoError(t, err)
+
+		// Get the snapID
+		img, err := OpenImage(ioctx, name1, NoSnapshot)
+		assert.NoError(t, err)
+		defer img.Close()
+
+		snapName := "mysnap"
+		snapshot, err := img.CreateSnapshot(snapName)
+		assert.NoError(t, err)
+		defer func() {
+			assert.NoError(t, snapshot.Remove())
+		}()
+
+		snapInfos, err := img.GetSnapshotNames()
+		assert.NoError(t, err)
+		require.Equal(t, 1, len(snapInfos))
+
+		snapID := snapInfos[0].Id
+
+		// Create a clone of the image using the snapshot.
+		err = CloneImageByID(ioctx, name1, snapID, ioctx, cloneName, optionsClone)
+		assert.NoError(t, err)
+		defer func() { assert.NoError(t, RemoveImage(ioctx, cloneName)) }()
+
+		imgNew, err := OpenImage(ioctx, cloneName, NoSnapshot)
+		defer func() {
+			assert.NoError(t, imgNew.Close())
+		}()
+		assert.NoError(t, err)
+
+		parentInfo, err := imgNew.GetParent()
+		assert.NoError(t, err)
+		assert.Equal(t, parentInfo.Image.ImageName, name1)
+		assert.Equal(t, parentInfo.Image.PoolName, poolname)
+		assert.False(t, parentInfo.Image.Trash)
+		assert.Equal(t, parentInfo.Snap.SnapName, snapName)
+		assert.Equal(t, parentInfo.Snap.ID, snapID)
+	})
+
+	t.Run("CloneFromGroupSnap", func(t *testing.T) {
+		err := GroupSnapCreate(ioctx, gname, "groupsnap")
+		assert.NoError(t, err)
+
+		cloneName := "img-clone"
+		optionsClone := NewRbdImageOptions()
+		defer optionsClone.Destroy()
+		err = optionsClone.SetUint64(ImageOptionCloneFormat, 2)
+		assert.NoError(t, err)
+
+		// Get the snapID of the image
+		img, err := OpenImageReadOnly(ioctx, name1, NoSnapshot)
+		assert.NoError(t, err)
+		defer img.Close()
+
+		snapInfos, err := img.GetSnapshotNames()
+		assert.NoError(t, err)
+		require.Equal(t, 1, len(snapInfos))
+
+		snapID := snapInfos[0].Id
+
+		// Create a clone of the image using the snapshot.
+		err = CloneImageByID(ioctx, name1, snapID, ioctx, cloneName, optionsClone)
+		assert.NoError(t, err)
+		defer func() { assert.NoError(t, RemoveImage(ioctx, cloneName)) }()
+
+		imgNew, err := OpenImage(ioctx, cloneName, NoSnapshot)
+		defer func() {
+			assert.NoError(t, imgNew.Close())
+		}()
+		assert.NoError(t, err)
+
+		parentInfo, err := imgNew.GetParent()
+		assert.NoError(t, err)
+		assert.Equal(t, parentInfo.Image.ImageName, name1)
+		assert.Equal(t, parentInfo.Snap.ID, snapID)
+		assert.Equal(t, parentInfo.Image.PoolName, poolname)
+		assert.False(t, parentInfo.Image.Trash)
+
+		err = GroupSnapRemove(ioctx, gname, "groupsnap")
+		assert.NoError(t, err)
+	})
+}