1 files changed, 89 insertions, 0 deletions
diff --git a/src/tools/rbd_mirror/image_map/SimplePolicy.cc b/src/tools/rbd_mirror/image_map/SimplePolicy.cc
new file mode 100644
index 000000000..f26805819
--- /dev/null
+++ b/src/tools/rbd_mirror/image_map/SimplePolicy.cc
@@ -0,0 +1,89 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "common/debug.h"
+#include "common/errno.h"
+
+#include "SimplePolicy.h"
+
+#define dout_context g_ceph_context
+#define dout_subsys ceph_subsys_rbd_mirror
+#undef dout_prefix
+#define dout_prefix *_dout << "rbd::mirror::image_map::SimplePolicy: " << this \
+                           << " " << __func__ << ": "
+namespace rbd {
+namespace mirror {
+namespace image_map {
+
+SimplePolicy::SimplePolicy(librados::IoCtx &ioctx)
+  : Policy(ioctx) {
+}
+
+size_t SimplePolicy::calc_images_per_instance(const InstanceToImageMap& map,
+                                              size_t image_count) {
+  size_t nr_instances = 0;
+  for (auto const &it : map) {
+    if (!Policy::is_dead_instance(it.first)) {
+      ++nr_instances;
+    }
+  }
+  ceph_assert(nr_instances > 0);
+
+  size_t images_per_instance = image_count / nr_instances;
+  if (images_per_instance == 0) {
+    ++images_per_instance;
+  }
+
+  return images_per_instance;
+}
+
+void SimplePolicy::do_shuffle_add_instances(
+    const InstanceToImageMap& map, size_t image_count,
+    std::set<std::string> *remap_global_image_ids) {
+  uint64_t images_per_instance = calc_images_per_instance(map, image_count);
+  dout(5) << "images per instance=" << images_per_instance << dendl;
+
+  for (auto const &instance : map) {
+    if (instance.second.size() <= images_per_instance) {
+      continue;
+    }
+
+    auto it = instance.second.begin();
+    uint64_t cut_off = instance.second.size() - images_per_instance;
+
+    while (it != instance.second.end() && cut_off > 0) {
+      if (Policy::is_image_shuffling(*it)) {
+        --cut_off;
+      } else if (Policy::can_shuffle_image(*it)) {
+        --cut_off;
+        remap_global_image_ids->emplace(*it);
+      }
+
+      ++it;
+    }
+  }
+}
+
+std::string SimplePolicy::do_map(const InstanceToImageMap& map,
+                                 const std::string &global_image_id) {
+  auto min_it = map.end();
+  for (auto it = map.begin(); it != map.end(); ++it) {
+    ceph_assert(it->second.find(global_image_id) == it->second.end());
+    if (Policy::is_dead_instance(it->first)) {
+      continue;
+    } else if (min_it == map.end()) {
+      min_it = it;
+    } else if (it->second.size() < min_it->second.size()) {
+      min_it = it;
+    }
+  }
+
+  ceph_assert(min_it != map.end());
+  dout(20) << "global_image_id=" << global_image_id << " maps to instance_id="
+           << min_it->first << dendl;
+  return min_it->first;
+}
+
+} // namespace image_map
+} // namespace mirror
+} // namespace rbd