1 files changed, 353 insertions, 0 deletions
diff --git a/src/rocksdb/util/delete_scheduler.cc b/src/rocksdb/util/delete_scheduler.cc
new file mode 100644
index 00000000..f5ee2844
--- /dev/null
+++ b/src/rocksdb/util/delete_scheduler.cc
@@ -0,0 +1,353 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#ifndef ROCKSDB_LITE
+
+#include "util/delete_scheduler.h"
+
+#include <thread>
+#include <vector>
+
+#include "port/port.h"
+#include "rocksdb/env.h"
+#include "util/logging.h"
+#include "util/mutexlock.h"
+#include "util/sst_file_manager_impl.h"
+#include "util/sync_point.h"
+
+namespace rocksdb {
+
+DeleteScheduler::DeleteScheduler(Env* env, int64_t rate_bytes_per_sec,
+                                 Logger* info_log,
+                                 SstFileManagerImpl* sst_file_manager,
+                                 double max_trash_db_ratio,
+                                 uint64_t bytes_max_delete_chunk)
+    : env_(env),
+      total_trash_size_(0),
+      rate_bytes_per_sec_(rate_bytes_per_sec),
+      pending_files_(0),
+      bytes_max_delete_chunk_(bytes_max_delete_chunk),
+      closing_(false),
+      cv_(&mu_),
+      info_log_(info_log),
+      sst_file_manager_(sst_file_manager),
+      max_trash_db_ratio_(max_trash_db_ratio) {
+  assert(sst_file_manager != nullptr);
+  assert(max_trash_db_ratio >= 0);
+  bg_thread_.reset(
+      new port::Thread(&DeleteScheduler::BackgroundEmptyTrash, this));
+}
+
+DeleteScheduler::~DeleteScheduler() {
+  {
+    InstrumentedMutexLock l(&mu_);
+    closing_ = true;
+    cv_.SignalAll();
+  }
+  if (bg_thread_) {
+    bg_thread_->join();
+  }
+}
+
+Status DeleteScheduler::DeleteFile(const std::string& file_path,
+                                   const std::string& dir_to_sync,
+                                   const bool force_bg) {
+  Status s;
+  if (rate_bytes_per_sec_.load() <= 0 || (!force_bg &&
+      total_trash_size_.load() >
+          sst_file_manager_->GetTotalSize() * max_trash_db_ratio_.load())) {
+    // Rate limiting is disabled or trash size makes up more than
+    // max_trash_db_ratio_ (default 25%) of the total DB size
+    TEST_SYNC_POINT("DeleteScheduler::DeleteFile");
+    s = env_->DeleteFile(file_path);
+    if (s.ok()) {
+      sst_file_manager_->OnDeleteFile(file_path);
+    }
+    return s;
+  }
+
+  // Move file to trash
+  std::string trash_file;
+  s = MarkAsTrash(file_path, &trash_file);
+
+  if (!s.ok()) {
+    ROCKS_LOG_ERROR(info_log_, "Failed to mark %s as trash", file_path.c_str());
+    s = env_->DeleteFile(file_path);
+    if (s.ok()) {
+      sst_file_manager_->OnDeleteFile(file_path);
+    }
+    return s;
+  }
+
+  // Update the total trash size
+  uint64_t trash_file_size = 0;
+  env_->GetFileSize(trash_file, &trash_file_size);
+  total_trash_size_.fetch_add(trash_file_size);
+
+  // Add file to delete queue
+  {
+    InstrumentedMutexLock l(&mu_);
+    queue_.emplace(trash_file, dir_to_sync);
+    pending_files_++;
+    if (pending_files_ == 1) {
+      cv_.SignalAll();
+    }
+  }
+  return s;
+}
+
+std::map<std::string, Status> DeleteScheduler::GetBackgroundErrors() {
+  InstrumentedMutexLock l(&mu_);
+  return bg_errors_;
+}
+
+const std::string DeleteScheduler::kTrashExtension = ".trash";
+bool DeleteScheduler::IsTrashFile(const std::string& file_path) {
+  return (file_path.size() >= kTrashExtension.size() &&
+          file_path.rfind(kTrashExtension) ==
+              file_path.size() - kTrashExtension.size());
+}
+
+Status DeleteScheduler::CleanupDirectory(Env* env, SstFileManagerImpl* sfm,
+                                         const std::string& path) {
+  Status s;
+  // Check if there are any files marked as trash in this path
+  std::vector<std::string> files_in_path;
+  s = env->GetChildren(path, &files_in_path);
+  if (!s.ok()) {
+    return s;
+  }
+  for (const std::string& current_file : files_in_path) {
+    if (!DeleteScheduler::IsTrashFile(current_file)) {
+      // not a trash file, skip
+      continue;
+    }
+
+    Status file_delete;
+    std::string trash_file = path + "/" + current_file;
+    if (sfm) {
+      // We have an SstFileManager that will schedule the file delete
+      sfm->OnAddFile(trash_file);
+      file_delete = sfm->ScheduleFileDeletion(trash_file, path);
+    } else {
+      // Delete the file immediately
+      file_delete = env->DeleteFile(trash_file);
+    }
+
+    if (s.ok() && !file_delete.ok()) {
+      s = file_delete;
+    }
+  }
+
+  return s;
+}
+
+Status DeleteScheduler::MarkAsTrash(const std::string& file_path,
+                                    std::string* trash_file) {
+  // Sanity check of the path
+  size_t idx = file_path.rfind("/");
+  if (idx == std::string::npos || idx == file_path.size() - 1) {
+    return Status::InvalidArgument("file_path is corrupted");
+  }
+
+  Status s;
+  if (DeleteScheduler::IsTrashFile(file_path)) {
+    // This is already a trash file
+    *trash_file = file_path;
+    return s;
+  }
+
+  *trash_file = file_path + kTrashExtension;
+  // TODO(tec) : Implement Env::RenameFileIfNotExist and remove
+  //             file_move_mu mutex.
+  int cnt = 0;
+  InstrumentedMutexLock l(&file_move_mu_);
+  while (true) {
+    s = env_->FileExists(*trash_file);
+    if (s.IsNotFound()) {
+      // We found a path for our file in trash
+      s = env_->RenameFile(file_path, *trash_file);
+      break;
+    } else if (s.ok()) {
+      // Name conflict, generate new random suffix
+      *trash_file = file_path + std::to_string(cnt) + kTrashExtension;
+    } else {
+      // Error during FileExists call, we cannot continue
+      break;
+    }
+    cnt++;
+  }
+  if (s.ok()) {
+    sst_file_manager_->OnMoveFile(file_path, *trash_file);
+  }
+  return s;
+}
+
+void DeleteScheduler::BackgroundEmptyTrash() {
+  TEST_SYNC_POINT("DeleteScheduler::BackgroundEmptyTrash");
+
+  while (true) {
+    InstrumentedMutexLock l(&mu_);
+    while (queue_.empty() && !closing_) {
+      cv_.Wait();
+    }
+
+    if (closing_) {
+      return;
+    }
+
+    // Delete all files in queue_
+    uint64_t start_time = env_->NowMicros();
+    uint64_t total_deleted_bytes = 0;
+    int64_t current_delete_rate = rate_bytes_per_sec_.load();
+    while (!queue_.empty() && !closing_) {
+      if (current_delete_rate != rate_bytes_per_sec_.load()) {
+        // User changed the delete rate
+        current_delete_rate = rate_bytes_per_sec_.load();
+        start_time = env_->NowMicros();
+        total_deleted_bytes = 0;
+      }
+
+      // Get new file to delete
+      const FileAndDir& fad = queue_.front();
+      std::string path_in_trash = fad.fname;
+
+      // We dont need to hold the lock while deleting the file
+      mu_.Unlock();
+      uint64_t deleted_bytes = 0;
+      bool is_complete = true;
+      // Delete file from trash and update total_penlty value
+      Status s =
+          DeleteTrashFile(path_in_trash, fad.dir, &deleted_bytes, &is_complete);
+      total_deleted_bytes += deleted_bytes;
+      mu_.Lock();
+      if (is_complete) {
+        queue_.pop();
+      }
+
+      if (!s.ok()) {
+        bg_errors_[path_in_trash] = s;
+      }
+
+      // Apply penlty if necessary
+      uint64_t total_penlty;
+      if (current_delete_rate > 0) {
+        // rate limiting is enabled
+        total_penlty =
+            ((total_deleted_bytes * kMicrosInSecond) / current_delete_rate);
+        while (!closing_ && !cv_.TimedWait(start_time + total_penlty)) {}
+      } else {
+        // rate limiting is disabled
+        total_penlty = 0;
+      }
+      TEST_SYNC_POINT_CALLBACK("DeleteScheduler::BackgroundEmptyTrash:Wait",
+                               &total_penlty);
+
+      if (is_complete) {
+        pending_files_--;
+      }
+      if (pending_files_ == 0) {
+        // Unblock WaitForEmptyTrash since there are no more files waiting
+        // to be deleted
+        cv_.SignalAll();
+      }
+    }
+  }
+}
+
+Status DeleteScheduler::DeleteTrashFile(const std::string& path_in_trash,
+                                        const std::string& dir_to_sync,
+                                        uint64_t* deleted_bytes,
+                                        bool* is_complete) {
+  uint64_t file_size;
+  Status s = env_->GetFileSize(path_in_trash, &file_size);
+  *is_complete = true;
+  TEST_SYNC_POINT("DeleteScheduler::DeleteTrashFile:DeleteFile");
+  if (s.ok()) {
+    bool need_full_delete = true;
+    if (bytes_max_delete_chunk_ != 0 && file_size > bytes_max_delete_chunk_) {
+      uint64_t num_hard_links = 2;
+      // We don't have to worry aobut data race between linking a new
+      // file after the number of file link check and ftruncte because
+      // the file is now in trash and no hardlink is supposed to create
+      // to trash files by RocksDB.
+      Status my_status = env_->NumFileLinks(path_in_trash, &num_hard_links);
+      if (my_status.ok()) {
+        if (num_hard_links == 1) {
+          std::unique_ptr<WritableFile> wf;
+          my_status =
+              env_->ReopenWritableFile(path_in_trash, &wf, EnvOptions());
+          if (my_status.ok()) {
+            my_status = wf->Truncate(file_size - bytes_max_delete_chunk_);
+            if (my_status.ok()) {
+              TEST_SYNC_POINT("DeleteScheduler::DeleteTrashFile:Fsync");
+              my_status = wf->Fsync();
+            }
+          }
+          if (my_status.ok()) {
+            *deleted_bytes = bytes_max_delete_chunk_;
+            need_full_delete = false;
+            *is_complete = false;
+          } else {
+            ROCKS_LOG_WARN(info_log_,
+                           "Failed to partially delete %s from trash -- %s",
+                           path_in_trash.c_str(), my_status.ToString().c_str());
+          }
+        } else {
+          ROCKS_LOG_INFO(info_log_,
+                         "Cannot delete %s slowly through ftruncate from trash "
+                         "as it has other links",
+                         path_in_trash.c_str());
+        }
+      } else if (!num_link_error_printed_) {
+        ROCKS_LOG_INFO(
+            info_log_,
+            "Cannot delete files slowly through ftruncate from trash "
+            "as Env::NumFileLinks() returns error: %s",
+            my_status.ToString().c_str());
+        num_link_error_printed_ = true;
+      }
+    }
+
+    if (need_full_delete) {
+      s = env_->DeleteFile(path_in_trash);
+      if (!dir_to_sync.empty()) {
+        std::unique_ptr<Directory> dir_obj;
+        if (s.ok()) {
+          s = env_->NewDirectory(dir_to_sync, &dir_obj);
+        }
+        if (s.ok()) {
+          s = dir_obj->Fsync();
+          TEST_SYNC_POINT_CALLBACK(
+              "DeleteScheduler::DeleteTrashFile::AfterSyncDir",
+              reinterpret_cast<void*>(const_cast<std::string*>(&dir_to_sync)));
+        }
+      }
+      *deleted_bytes = file_size;
+      sst_file_manager_->OnDeleteFile(path_in_trash);
+    }
+  }
+  if (!s.ok()) {
+    // Error while getting file size or while deleting
+    ROCKS_LOG_ERROR(info_log_, "Failed to delete %s from trash -- %s",
+                    path_in_trash.c_str(), s.ToString().c_str());
+    *deleted_bytes = 0;
+  } else {
+    total_trash_size_.fetch_sub(*deleted_bytes);
+  }
+
+  return s;
+}
+
+void DeleteScheduler::WaitForEmptyTrash() {
+  InstrumentedMutexLock l(&mu_);
+  while (pending_files_ > 0 && !closing_) {
+    cv_.Wait();
+  }
+}
+
+}  // namespace rocksdb
+
+#endif  // ROCKSDB_LITE