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: v16.1.0~298^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=refs%2Fpull%2F38517%2Fhead;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>
---

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 f9550dcb5b42..50a155d24182 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 d2c8ee27278e..1b9d08f0b48d 100644
--- a/src/tools/rbd_mirror/image_replayer/snapshot/Replayer.cc
+++ b/src/tools/rbd_mirror/image_replayer/snapshot/Replayer.cc
@@ -552,7 +552,10 @@ 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