rbd: dlsym-ify GroupSnapGetInfo

Signed-off-by: Niels de Vos <[email protected]>

rbd/group_snap_info.go

@@ -1,4 +1,4 @@
-//go:build ceph_preview && !(nautilus || octopus || pacific || quincy || reef || squid)
+//go:build ceph_preview
 
 package rbd
 
@@ -8,17 +8,83 @@ package rbd
 #include <stdlib.h>
 #include <rbd/librbd.h>
 
+// Types and constants are copied from librbd.h with added "_" as prefix. This
+// prevents redefinition of the types on librbd versions that have them
+// already.
+
+typedef enum {
+  _RBD_GROUP_SNAP_NAMESPACE_TYPE_USER = 0
+} _rbd_group_snap_namespace_type_t;
+
+typedef struct {
+  char *image_name;
+  int64_t pool_id;
+  uint64_t snap_id;
+} _rbd_group_image_snap_info_t;
+
+typedef struct {
+  char *id;
+  char *name;
+  char *image_snap_name;
+  rbd_group_snap_state_t state;
+  _rbd_group_snap_namespace_type_t namespace_type;
+  size_t image_snaps_count;
+  _rbd_group_image_snap_info_t *image_snaps;
+} _rbd_group_snap_info2_t;
+
+// rbd_group_snap_get_info_fn matches the rbd_group_snap_get_info function signature.
+typedef int(*rbd_group_snap_get_info_fn)(rados_ioctx_t group_p,
+                                         const char *group_name,
+                                         const char *snap_name,
+                                         _rbd_group_snap_info2_t *snaps);
+
+// rbd_group_snap_get_info_dlsym take *fn as rbd_group_snap_get_info_fn and
+// calls the dynamically loaded rbd_group_snap_get_info function passed as 1st
+// argument.
+static inline int rbd_group_snap_get_info_dlsym(void *fn,
+                                                rados_ioctx_t group_p,
+                                                const char *group_name,
+                                                const char *snap_name,
+                                                _rbd_group_snap_info2_t *snaps) {
+  // cast function pointer fn to rbd_group_snap_get_info and call the function
+  return ((rbd_group_snap_get_info_fn) fn)(group_p, group_name, snap_name, snaps);
+}
+
+// rbd_group_snap_get_info_cleanup_fn matches the rbd_group_snap_get_info_cleanup function signature.
+typedef int(*rbd_group_snap_get_info_cleanup_fn)(_rbd_group_snap_info2_t *snaps);
+
+// rbd_group_snap_get_info_cleanup_dlsym take *fn as rbd_group_snap_get_info_cleanup_fn and
+// calls the dynamically loaded rbd_group_snap_get_info_cleanup function passed as 1st
+// argument.
+static inline int rbd_group_snap_get_info_cleanup_dlsym(void *fn,
+                                                _rbd_group_snap_info2_t *snaps) {
+  // cast function pointer fn to rbd_group_snap_get_info_cleanup and call the function
+  return ((rbd_group_snap_get_info_cleanup_fn) fn)(snaps);
+}
 */
 import "C"
 
 import (
+	"fmt"
+	"sync"
 	"unsafe"
 
 	"github.com/ceph/go-ceph/internal/cutil"
+	"github.com/ceph/go-ceph/internal/dlsym"
 	"github.com/ceph/go-ceph/rados"
 )
 
-type imgSnapInfoArray [cutil.MaxIdx]C.rbd_group_image_snap_info_t
+type imgSnapInfoArray [cutil.MaxIdx]C._rbd_group_image_snap_info_t
+
+var (
+	rbdGroupGetSnapInfoOnce sync.Once
+	rbdGroupGetSnapInfo     unsafe.Pointer
+	rbdGroupGetSnapInfoErr  error
+
+	rbdGroupSnapGetInfoCleanupOnce sync.Once
+	rbdGroupSnapGetInfoCleanup     unsafe.Pointer
+	rbdGroupSnapGetInfoCleanupErr  error
+)
 
 // GroupSnapGetInfo returns a slice of RBD image snapshots that are part of a
 // group snapshot.
@@ -30,14 +96,31 @@ type imgSnapInfoArray [cutil.MaxIdx]C.rbd_group_image_snap_info_t
 //	                        const char *snap_name,
 //	                        rbd_group_snap_info2_t *snaps);
 func GroupSnapGetInfo(ioctx *rados.IOContext, group, snap string) (GroupSnapInfo, error) {
+	rbdGroupGetSnapInfoOnce.Do(func() {
+		rbdGroupGetSnapInfo, rbdGroupGetSnapInfoErr = dlsym.LookupSymbol("rbd_group_snap_get_info")
+	})
+
+	if rbdGroupGetSnapInfoErr != nil {
+		return GroupSnapInfo{}, fmt.Errorf("%w: %w", ErrNotImplemented, rbdGroupGetSnapInfoErr)
+	}
+
+	rbdGroupSnapGetInfoCleanupOnce.Do(func() {
+		rbdGroupSnapGetInfoCleanup, rbdGroupSnapGetInfoCleanupErr = dlsym.LookupSymbol("rbd_group_snap_get_info_cleanup")
+	})
+
+	if rbdGroupSnapGetInfoCleanupErr != nil {
+		return GroupSnapInfo{}, fmt.Errorf("%w: %w", ErrNotImplemented, rbdGroupSnapGetInfoCleanupErr)
+	}
+
 	cGroupName := C.CString(group)
 	defer C.free(unsafe.Pointer(cGroupName))
 	cSnapName := C.CString(snap)
 	defer C.free(unsafe.Pointer(cSnapName))
 
-	cSnapInfo := C.rbd_group_snap_info2_t{}
+	cSnapInfo := C._rbd_group_snap_info2_t{}
 
-	ret := C.rbd_group_snap_get_info(
+	ret := C.rbd_group_snap_get_info_dlsym(
+		rbdGroupGetSnapInfo,
 		cephIoctx(ioctx),
 		cGroupName,
 		cSnapName,
@@ -66,6 +149,6 @@ func GroupSnapGetInfo(ioctx *rados.IOContext, group, snap string) (GroupSnapInfo
 	}
 
 	// free C memory allocated by C.rbd_group_snap_get_info call
-	C.rbd_group_snap_get_info_cleanup(&cSnapInfo)
+	C.rbd_group_snap_get_info_cleanup_dlsym(rbdGroupSnapGetInfoCleanup, &cSnapInfo)
 	return snapInfo, nil
 }

rbd/group_snap_test.go

@@ -1,6 +1,7 @@
 package rbd
 
 import (
+	"errors"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -113,6 +114,9 @@ func TestGroupSnapshots(t *testing.T) {
 		}()
 
 		info, err := GroupSnapGetInfo(ioctx, gname, "snapDetails")
+		if errors.Is(err, ErrNotImplemented) {
+			t.Skipf("GroupSnapGetInfo is not supported: %v", err)
+		}
 		assert.NoError(t, err)
 
 		assert.Equal(t, GroupSnapStateComplete, info.State)