rebase: update vendored go-ceph to v0.6

Closes: #1547
Signed-off-by: Niels de Vos <ndevos@redhat.com>

vendor/github.com/ceph/go-ceph/rbd/snapshot_octopus.go

@@ -0,0 +1,66 @@
+// +build octopus
+
+package rbd
+
+// #cgo LDFLAGS: -lrbd
+// #include <stdlib.h>
+// #include <rbd/librbd.h>
+import "C"
+
+import (
+	"unsafe"
+
+	"github.com/ceph/go-ceph/internal/retry"
+)
+
+// GetSnapID returns the snapshot ID for the given snapshot name.
+//
+// Implements:
+//  int rbd_snap_get_id(rbd_image_t image, const char *snapname, uint64_t *snap_id)
+func (image *Image) GetSnapID(snapName string) (uint64, error) {
+	var snapID C.uint64_t
+	if err := image.validate(imageIsOpen); err != nil {
+		return uint64(snapID), err
+	}
+	if snapName == "" {
+		return uint64(snapID), ErrSnapshotNoName
+	}
+
+	cSnapName := C.CString(snapName)
+	defer C.free(unsafe.Pointer(cSnapName))
+
+	ret := C.rbd_snap_get_id(image.image, cSnapName, &snapID)
+	return uint64(snapID), getError(ret)
+}
+
+// GetSnapByID returns the snapshot name for the given snapshot ID.
+//
+// Implements:
+//  int rbd_snap_get_name(rbd_image_t image, uint64_t snap_id, char *snapname, size_t *name_len)
+func (image *Image) GetSnapByID(snapID uint64) (string, error) {
+	if err := image.validate(imageIsOpen); err != nil {
+		return "", err
+	}
+
+	var (
+		buf []byte
+		err error
+	)
+	// range from 1k to 64KiB
+	retry.WithSizes(1024, 1<<16, func(len int) retry.Hint {
+		cLen := C.size_t(len)
+		buf = make([]byte, cLen)
+		ret := C.rbd_snap_get_name(
+			image.image,
+			(C.uint64_t)(snapID),
+			(*C.char)(unsafe.Pointer(&buf[0])),
+			&cLen)
+		err = getError(ret)
+		return retry.Size(int(cLen)).If(err == errRange)
+	})
+
+	if err != nil {
+		return "", err
+	}
+	return C.GoString((*C.char)(unsafe.Pointer(&buf[0]))), nil
+}