From: Jason Dillaman <dillaman@redhat.com>
Date: Thu, 10 Dec 2020 04:17:24 +0000 (-0500)
Subject: rbd-mirror: do not attempt to unlink from more recent snapshots
X-Git-Tag: v15.2.13~2^2~14^2~4
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=ec9a4e1cf5c9843883c7a32e474da1beacd3ce81;p=ceph.git

rbd-mirror: do not attempt to unlink from more recent snapshots

The snapshot-based mirroring replayer should only attempt to unlink
from any snapshots that are older than the end remote snapshot id to
prevent the remote side from incorrectly deleted the snapshot.

Fixes: https://tracker.ceph.com/issues/48527
Signed-off-by: Jason Dillaman <dillaman@redhat.com>
(cherry picked from commit 78f8abce2d90d7c9bcf7b4bd4d805c3fe0b39b03)
---

diff --git a/src/test/rbd_mirror/image_replayer/snapshot/test_mock_Replayer.cc b/src/test/rbd_mirror/image_replayer/snapshot/test_mock_Replayer.cc
index d1117bb79eb..4ce139d21f4 100644
--- a/src/test/rbd_mirror/image_replayer/snapshot/test_mock_Replayer.cc
+++ b/src/test/rbd_mirror/image_replayer/snapshot/test_mock_Replayer.cc
@@ -783,7 +783,24 @@ TEST_F(TestMockImageReplayerSnapshotReplayer, SyncSnapshot) {
          1, true, 0, {{1, CEPH_NOSNAP}}},
        0, {}, 0, 0, {}}},
     }, 0);
-  expect_is_refresh_required(mock_remote_image_ctx, false);
+  expect_is_refresh_required(mock_remote_image_ctx, true);
+  expect_refresh(
+    mock_remote_image_ctx, {
+      {2U, librbd::SnapInfo{"snap2", cls::rbd::UserSnapshotNamespace{},
+       0, {}, 0, 0, {}}},
+      {3U, librbd::SnapInfo{"snap3", cls::rbd::MirrorSnapshotNamespace{
+         cls::rbd::MIRROR_SNAPSHOT_STATE_PRIMARY, {""},
+         "", CEPH_NOSNAP, true, 0, {}},
+       0, {}, 0, 0, {}}},
+      {4U, librbd::SnapInfo{"snap4", cls::rbd::MirrorSnapshotNamespace{
+         cls::rbd::MIRROR_SNAPSHOT_STATE_PRIMARY, {"remote mirror peer uuid"},
+         "", CEPH_NOSNAP, true, 0, {}},
+       0, {}, 0, 0, {}}},
+      {5U, librbd::SnapInfo{"snap5", cls::rbd::MirrorSnapshotNamespace{
+         cls::rbd::MIRROR_SNAPSHOT_STATE_PRIMARY, {"remote mirror peer uuid"},
+         "", CEPH_NOSNAP, true, 0, {}},
+       0, {}, 0, 0, {}}}
+    }, 0);
   expect_snapshot_copy(mock_snapshot_copy_request, 1, 4, 11,
                        {{1, 11}, {2, 12}, {4, CEPH_NOSNAP}}, 0);
   expect_get_image_state(mock_get_image_state_request, 4, 0);
diff --git a/src/tools/rbd_mirror/image_replayer/snapshot/Replayer.cc b/src/tools/rbd_mirror/image_replayer/snapshot/Replayer.cc
index 6fa7277ef47..f46270c927f 100644
--- a/src/tools/rbd_mirror/image_replayer/snapshot/Replayer.cc
+++ b/src/tools/rbd_mirror/image_replayer/snapshot/Replayer.cc
@@ -555,7 +555,10 @@ void Replayer<I>::scan_remote_mirror_snapshots(
         ceph_assert(m_local_mirror_snap_ns.primary_mirror_uuid ==
                       m_state_builder->remote_mirror_uuid);
 
-        unlink_snap_ids.insert(remote_snap_id);
+        if (m_remote_snap_id_end == CEPH_NOSNAP) {
+          // haven't found the end snap so treat this as a candidate for unlink
+          unlink_snap_ids.insert(remote_snap_id);
+        }
         if (m_local_mirror_snap_ns.complete &&
             m_local_mirror_snap_ns.primary_snap_id >= remote_snap_id) {
           // skip past completed remote snapshot