librbd: get_parent_info should protect against invalid parent

get_parent_info should return -ENOENT if the image does not
have an associated parent image.

Signed-off-by: Jason Dillaman <dillaman@redhat.com>
(cherry picked from commit 21afd0ef8e1fb81c5ace5fd403513c542e2413e3)

diff --git a/src/librbd/internal.cc b/src/librbd/internal.cc
index 8f5f040f52a9940098ac6e355f2c123f20509a87..2651ba6208f873702d3240c91c72e4b3bc932b21 100644 (file)
--- a/src/librbd/internal.cc
+++ b/src/librbd/internal.cc
@@ -1426,6 +1426,9 @@ reprotect_and_return_err:
 
     RWLock::RLocker l(ictx->snap_lock);
     RWLock::RLocker l2(ictx->parent_lock);
+    if (ictx->parent == NULL) {
+      return -ENOENT;
+    }
 
     parent_spec parent_spec;