From: Jason Dillaman <dillaman@redhat.com>
Date: Wed, 6 May 2015 21:37:58 +0000 (-0400)
Subject: librbd: fast diff of first snapshot loads incorrect object map
X-Git-Tag: v9.0.2~229^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=refs%2Fpull%2F4593%2Fhead;p=ceph.git

librbd: fast diff of first snapshot loads incorrect object map

The ImageCtx::snaps collection is stored in newest->oldest order,
so the first snapshot id should be retrieved from the back of the
array.

Signed-off-by: Jason Dillaman <dillaman@redhat.com>
---

diff --git a/src/librbd/internal.cc b/src/librbd/internal.cc
index 05be815b3b3..c197c88ff48 100644
--- a/src/librbd/internal.cc
+++ b/src/librbd/internal.cc
@@ -72,7 +72,7 @@ int diff_object_map(ImageCtx* ictx, uint64_t from_snap_id, uint64_t to_snap_id,
   bool diff_from_start = (from_snap_id == 0);
   if (from_snap_id == 0) {
     if (!ictx->snaps.empty()) {
-      from_snap_id = ictx->snaps.front();
+      from_snap_id = ictx->snaps.back();
     } else {
       from_snap_id = CEPH_NOSNAP;
     }