1 files changed, 124 insertions, 0 deletions
diff --git a/src/rocksdb/db/error_handler.h b/src/rocksdb/db/error_handler.h
new file mode 100644
index 000000000..34e08a525
--- /dev/null
+++ b/src/rocksdb/db/error_handler.h
@@ -0,0 +1,124 @@
+//  Copyright (c) 2018-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).
+#pragma once
+
+#include "monitoring/instrumented_mutex.h"
+#include "options/db_options.h"
+#include "rocksdb/io_status.h"
+#include "rocksdb/listener.h"
+#include "rocksdb/status.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+class DBImpl;
+
+// This structure is used to store the DB recovery context. The context is
+// the information that related to the recover actions. For example, it contains
+// FlushReason, which tells the flush job why this flush is called.
+struct DBRecoverContext {
+  FlushReason flush_reason;
+
+  DBRecoverContext() : flush_reason(FlushReason::kErrorRecovery) {}
+
+  DBRecoverContext(FlushReason reason) : flush_reason(reason) {}
+};
+
+class ErrorHandler {
+ public:
+  ErrorHandler(DBImpl* db, const ImmutableDBOptions& db_options,
+               InstrumentedMutex* db_mutex)
+      : db_(db),
+        db_options_(db_options),
+        cv_(db_mutex),
+        end_recovery_(false),
+        recovery_thread_(nullptr),
+        db_mutex_(db_mutex),
+        auto_recovery_(false),
+        recovery_in_prog_(false),
+        soft_error_no_bg_work_(false),
+        is_db_stopped_(false),
+        bg_error_stats_(db_options.statistics) {
+    // Clear the checked flag for uninitialized errors
+    bg_error_.PermitUncheckedError();
+    recovery_error_.PermitUncheckedError();
+    recovery_io_error_.PermitUncheckedError();
+  }
+
+  void EnableAutoRecovery() { auto_recovery_ = true; }
+
+  Status::Severity GetErrorSeverity(BackgroundErrorReason reason,
+                                    Status::Code code, Status::SubCode subcode);
+
+  const Status& SetBGError(const Status& bg_err, BackgroundErrorReason reason);
+
+  Status GetBGError() const { return bg_error_; }
+
+  Status GetRecoveryError() const { return recovery_error_; }
+
+  Status ClearBGError();
+
+  bool IsDBStopped() { return is_db_stopped_.load(std::memory_order_acquire); }
+
+  bool IsBGWorkStopped() {
+    assert(db_mutex_);
+    db_mutex_->AssertHeld();
+    return !bg_error_.ok() &&
+           (bg_error_.severity() >= Status::Severity::kHardError ||
+            !auto_recovery_ || soft_error_no_bg_work_);
+  }
+
+  bool IsSoftErrorNoBGWork() { return soft_error_no_bg_work_; }
+
+  bool IsRecoveryInProgress() { return recovery_in_prog_; }
+
+  Status RecoverFromBGError(bool is_manual = false);
+  void CancelErrorRecovery();
+
+  void EndAutoRecovery();
+
+ private:
+  DBImpl* db_;
+  const ImmutableDBOptions& db_options_;
+  Status bg_error_;
+  // A separate Status variable used to record any errors during the
+  // recovery process from hard errors
+  Status recovery_error_;
+  // A separate IO Status variable used to record any IO errors during
+  // the recovery process. At the same time, recovery_error_ is also set.
+  IOStatus recovery_io_error_;
+  // The condition variable used with db_mutex during auto resume for time
+  // wait.
+  InstrumentedCondVar cv_;
+  bool end_recovery_;
+  std::unique_ptr<port::Thread> recovery_thread_;
+
+  InstrumentedMutex* db_mutex_;
+  // A flag indicating whether automatic recovery from errors is enabled
+  bool auto_recovery_;
+  bool recovery_in_prog_;
+  // A flag to indicate that for the soft error, we should not allow any
+  // background work except the work is from recovery.
+  bool soft_error_no_bg_work_;
+
+  // Used to store the context for recover, such as flush reason.
+  DBRecoverContext recover_context_;
+  std::atomic<bool> is_db_stopped_;
+
+  // The pointer of DB statistics.
+  std::shared_ptr<Statistics> bg_error_stats_;
+
+  const Status& HandleKnownErrors(const Status& bg_err,
+                                  BackgroundErrorReason reason);
+  Status OverrideNoSpaceError(const Status& bg_error, bool* auto_recovery);
+  void RecoverFromNoSpace();
+  const Status& StartRecoverFromRetryableBGIOError(const IOStatus& io_error);
+  void RecoverFromRetryableBGIOError();
+  // First, if it is in recovery and the recovery_error is ok. Set the
+  // recovery_error_ to bg_err. Second, if the severity is higher than the
+  // current bg_error_, overwrite it.
+  void CheckAndSetRecoveryAndBGError(const Status& bg_err);
+};
+
+}  // namespace ROCKSDB_NAMESPACE