From d2d4bb42d59566afba8ce47b2bb1c12a47e5541a Mon Sep 17 00:00:00 2001
From: Jason Dillaman <dillaman@redhat.com>
Date: Mon, 14 Dec 2015 10:31:54 -0500
Subject: [PATCH] librbd: refresh object map after rollback

An image refresh will no longer trigger an automatic object map
reload, therefore explicitly reload the object map after rollback.

Signed-off-by: Jason Dillaman <dillaman@redhat.com>
---
 .../operation/SnapshotRollbackRequest.cc      | 50 ++++++++++++++++++-
 .../operation/SnapshotRollbackRequest.h       | 24 ++++++---
 2 files changed, 66 insertions(+), 8 deletions(-)

diff --git a/src/librbd/operation/SnapshotRollbackRequest.cc b/src/librbd/operation/SnapshotRollbackRequest.cc
index a0cb47cb85f58..f7df78be35e36 100644
--- a/src/librbd/operation/SnapshotRollbackRequest.cc
+++ b/src/librbd/operation/SnapshotRollbackRequest.cc
@@ -36,6 +36,9 @@ std::ostream& operator<<(std::ostream& os,
   case SnapshotRollbackRequest<I>::STATE_ROLLBACK_OBJECTS:
     os << "ROLLBACK_OBJECTS";
     break;
+  case SnapshotRollbackRequest<I>::STATE_REFRESH_OBJECT_MAP:
+    os << "REFRESH_OBJECT_MAP";
+    break;
   case SnapshotRollbackRequest<I>::STATE_INVALIDATE_CACHE:
     os << "INVALIDATE_CACHE";
     break;
@@ -88,7 +91,13 @@ SnapshotRollbackRequest<I>::SnapshotRollbackRequest(I &image_ctx,
                                                     uint64_t snap_size,
                                                     ProgressContext &prog_ctx)
   : Request<I>(image_ctx, on_finish), m_snap_name(snap_name),
-    m_snap_id(snap_id), m_snap_size(snap_size), m_prog_ctx(prog_ctx) {
+    m_snap_id(snap_id), m_snap_size(snap_size), m_prog_ctx(prog_ctx),
+    m_object_map(nullptr) {
+}
+
+template <typename I>
+SnapshotRollbackRequest<I>::~SnapshotRollbackRequest() {
+  delete m_object_map;
 }
 
 template <typename I>
@@ -117,6 +126,9 @@ bool SnapshotRollbackRequest<I>::should_complete(int r) {
     send_rollback_objects();
     break;
   case STATE_ROLLBACK_OBJECTS:
+    finished = send_refresh_object_map();
+    break;
+  case STATE_REFRESH_OBJECT_MAP:
     finished = send_invalidate_cache();
     break;
   case STATE_INVALIDATE_CACHE:
@@ -202,11 +214,36 @@ void SnapshotRollbackRequest<I>::send_rollback_objects() {
   throttle->start_ops(image_ctx.concurrent_management_ops);
 }
 
+template <typename I>
+bool SnapshotRollbackRequest<I>::send_refresh_object_map() {
+  I &image_ctx = this->m_image_ctx;
+  assert(image_ctx.owner_lock.is_locked());
+
+  if (image_ctx.object_map == nullptr) {
+    return send_invalidate_cache();
+  }
+
+  CephContext *cct = image_ctx.cct;
+  ldout(cct, 5) << this << " " << __func__ << dendl;
+  m_state = STATE_REFRESH_OBJECT_MAP;
+
+  m_object_map = image_ctx.create_object_map(CEPH_NOSNAP);
+
+  image_ctx.owner_lock.put_read();
+  Context *ctx = this->create_callback_context();
+  m_object_map->open(ctx);
+  image_ctx.owner_lock.get_read();
+
+  return false;
+}
+
 template <typename I>
 bool SnapshotRollbackRequest<I>::send_invalidate_cache() {
   I &image_ctx = this->m_image_ctx;
   assert(image_ctx.owner_lock.is_locked());
 
+  apply();
+
   if (image_ctx.object_cacher == NULL) {
     return true;
   }
@@ -219,6 +256,17 @@ bool SnapshotRollbackRequest<I>::send_invalidate_cache() {
   return false;
 }
 
+template <typename I>
+void SnapshotRollbackRequest<I>::apply() {
+  I &image_ctx = this->m_image_ctx;
+
+  assert(image_ctx.owner_lock.is_locked());
+  RWLock::WLocker snap_locker(image_ctx.snap_lock);
+  if (image_ctx.object_map != nullptr) {
+    std::swap(m_object_map, image_ctx.object_map);
+  }
+}
+
 } // namespace operation
 } // namespace librbd
 
diff --git a/src/librbd/operation/SnapshotRollbackRequest.h b/src/librbd/operation/SnapshotRollbackRequest.h
index f66fc5ba0b111..54dd742a3da6d 100644
--- a/src/librbd/operation/SnapshotRollbackRequest.h
+++ b/src/librbd/operation/SnapshotRollbackRequest.h
@@ -5,6 +5,7 @@
 #define CEPH_LIBRBD_OPERATION_SNAPSHOT_ROLLBACK_REQUEST_H
 
 #include "librbd/operation/Request.h"
+#include "librbd/ImageCtx.h"
 #include "librbd/internal.h"
 #include <string>
 
@@ -34,13 +35,16 @@ public:
    *  . . . . > STATE_ROLLBACK_OBJECT_MAP
    *  .               |
    *  .               v
-   *  . . . . > STATE_ROLLBACK_OBJECTS . . .
-   *                  |                    .
-   *                  v                    .
-   *            STATE_INVALIDATE_CACHE     .
-   *                  |                    .
-   *                  v                    .
-   *              <finish> < . . . . . . . .
+   *  . . . . > STATE_ROLLBACK_OBJECTS . . . . . . . . . . .
+   *                  |                                    .
+   *                  v                                    .
+   *            STATE_REFRESH_OBJECT_MAP  (skip if object  .
+   *                  |                    map disabled)   .
+   *                  v                                    .
+   *            STATE_INVALIDATE_CACHE                     .
+   *                  |                                    .
+   *                  v                                    .
+   *              <finish> < . . . . . . . . . . . . . . . .
    *
    * @endverbatim
    *
@@ -52,12 +56,14 @@ public:
     STATE_RESIZE_IMAGE,
     STATE_ROLLBACK_OBJECT_MAP,
     STATE_ROLLBACK_OBJECTS,
+    STATE_REFRESH_OBJECT_MAP,
     STATE_INVALIDATE_CACHE
   };
 
   SnapshotRollbackRequest(ImageCtxT &image_ctx, Context *on_finish,
                           const std::string &snap_name, uint64_t snap_id,
                           uint64_t snap_size, ProgressContext &prog_ctx);
+  virtual ~SnapshotRollbackRequest();
 
 protected:
   virtual void send_op();
@@ -76,11 +82,15 @@ private:
   NoOpProgressContext m_no_op_prog_ctx;
   State m_state;
 
+  decltype(ImageCtxT::object_map) m_object_map;
+
   void send_resize_image();
   void send_rollback_object_map();
   void send_rollback_objects();
+  bool send_refresh_object_map();
   bool send_invalidate_cache();
 
+  void apply();
 };
 
 } // namespace operation
-- 
2.39.5