1 files changed, 164 insertions, 0 deletions
diff --git a/src/librbd/cache/pwl/DiscardRequest.cc b/src/librbd/cache/pwl/DiscardRequest.cc
new file mode 100644
index 000000000..eaf24137d
--- /dev/null
+++ b/src/librbd/cache/pwl/DiscardRequest.cc
@@ -0,0 +1,164 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "common/dout.h"
+#include "common/errno.h"
+#include "common/hostname.h"
+#include "librbd/asio/ContextWQ.h"
+#include "librbd/cache/pwl/DiscardRequest.h"
+
+#if __has_include(<filesystem>)
+#include <filesystem>
+namespace fs = std::filesystem;
+#elif __has_include(<experimental/filesystem>)
+#include <experimental/filesystem>
+namespace fs = std::experimental::filesystem;
+#endif
+
+#include "librbd/cache/pwl/ImageCacheState.h"
+
+#include "librbd/cache/Types.h"
+#include "librbd/io/ImageDispatcherInterface.h"
+#include "librbd/ImageCtx.h"
+#include "librbd/Utils.h"
+
+
+#define dout_subsys ceph_subsys_rbd_pwl
+#undef dout_prefix
+#define dout_prefix *_dout << "librbd::cache::pwl:DiscardRequest: " \
+                           << this << " " << __func__ << ": "
+
+namespace librbd {
+namespace cache {
+namespace pwl {
+
+using librbd::util::create_async_context_callback;
+using librbd::util::create_context_callback;
+
+template <typename I>
+DiscardRequest<I>* DiscardRequest<I>::create(
+    I &image_ctx,
+    plugin::Api<I>& plugin_api,
+    Context *on_finish) {
+  return new DiscardRequest(image_ctx, plugin_api, on_finish);
+}
+
+template <typename I>
+DiscardRequest<I>::DiscardRequest(
+    I &image_ctx,
+    plugin::Api<I>& plugin_api,
+    Context *on_finish)
+  : m_image_ctx(image_ctx),
+    m_plugin_api(plugin_api),
+    m_on_finish(create_async_context_callback(image_ctx, on_finish)),
+    m_error_result(0) {
+}
+
+template <typename I>
+void DiscardRequest<I>::send() {
+  delete_image_cache_file();
+}
+
+template <typename I>
+void DiscardRequest<I>::delete_image_cache_file() {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 10) << dendl;
+
+  m_cache_state = ImageCacheState<I>::get_image_cache_state(&m_image_ctx, m_plugin_api);
+  if (!m_cache_state) {
+    remove_feature_bit();
+    return;
+  }
+  if (m_cache_state->present &&
+      !m_cache_state->host.compare(ceph_get_short_hostname()) &&
+      fs::exists(m_cache_state->path)) {
+    std::error_code ec;
+    fs::remove(m_cache_state->path, ec);
+    if (ec) {
+      lderr(cct) << "failed to remove persistent cache file: " << ec.message()
+                 << dendl;
+      // not fatal
+    }
+  }
+
+  remove_image_cache_state();
+}
+
+template <typename I>
+void DiscardRequest<I>::remove_image_cache_state() {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 10) << dendl;
+
+  using klass = DiscardRequest<I>;
+  Context *ctx = create_context_callback<klass, &klass::handle_remove_image_cache_state>(
+    this);
+
+  m_cache_state->clear_image_cache_state(ctx);
+}
+
+template <typename I>
+void DiscardRequest<I>::handle_remove_image_cache_state(int r) {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 10) << dendl;
+
+  if (r < 0) {
+    lderr(cct) << "failed to remove the image cache state: " << cpp_strerror(r)
+               << dendl;
+    save_result(r);
+    finish();
+    return;
+  }
+
+  remove_feature_bit();
+}
+
+template <typename I>
+void DiscardRequest<I>::remove_feature_bit() {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 10) << dendl;
+
+  uint64_t new_features = m_image_ctx.features & ~RBD_FEATURE_DIRTY_CACHE;
+  uint64_t features_mask = RBD_FEATURE_DIRTY_CACHE;
+  ldout(cct, 10) << "old_features=" << m_image_ctx.features
+                 << ", new_features=" << new_features
+                 << ", features_mask=" << features_mask
+                 << dendl;
+
+  int r = librbd::cls_client::set_features(&m_image_ctx.md_ctx, m_image_ctx.header_oid,
+                                           new_features, features_mask);
+  m_image_ctx.features &= ~RBD_FEATURE_DIRTY_CACHE;
+  using klass = DiscardRequest<I>;
+  Context *ctx = create_context_callback<klass, &klass::handle_remove_feature_bit>(
+    this);
+  ctx->complete(r);
+}
+
+template <typename I>
+void DiscardRequest<I>::handle_remove_feature_bit(int r) {
+  CephContext *cct = m_image_ctx.cct;
+  ldout(cct, 10) << dendl;
+
+  if (r < 0) {
+    lderr(cct) << "failed to remove the feature bit: " << cpp_strerror(r)
+               << dendl;
+    save_result(r);
+  }
+  finish();
+}
+
+template <typename I>
+void DiscardRequest<I>::finish() {
+  if (m_cache_state) {
+    delete m_cache_state;
+    m_cache_state = nullptr;
+  }
+
+  m_on_finish->complete(m_error_result);
+  delete this;
+}
+
+} // namespace pwl
+} // namespace cache
+} // namespace librbd
+
+template class librbd::cache::pwl::DiscardRequest<librbd::ImageCtx>;