librbd: set deleted parent pointer to null

Fixes: http://tracker.ceph.com/issues/22158
Signed-off-by: Jason Dillaman <dillaman@redhat.com>
(cherry picked from commit 7b53256bb825383fc604a96d71bcd51c36668cc4)

diff --git a/src/librbd/image/RefreshParentRequest.cc b/src/librbd/image/RefreshParentRequest.cc
index 28058abe7b557f620eddd7b850979920c02ccfe7..0ed977e54c1c2cc06910565afde09a06e4581789 100644 (file)
--- a/src/librbd/image/RefreshParentRequest.cc
+++ b/src/librbd/image/RefreshParentRequest.cc
@@ -210,6 +210,8 @@ Context *RefreshParentRequest<I>::handle_close_parent(int *result) {
   ldout(cct, 10) << this << " " << __func__ << " r=" << *result << dendl;
 
   delete m_parent_image_ctx;
+  m_parent_image_ctx = nullptr;
+
   if (*result < 0) {
     lderr(cct) << "failed to close parent image: " << cpp_strerror(*result)
                << dendl;