// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
 * Ceph - scalable distributed file system
 *
 * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
 *
 * This is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License version 2.1, as published by the Free Software
 * Foundation.  See file COPYING.
 *
 */

#ifndef CEPH_MBACKFILL_H
#define CEPH_MBACKFILL_H

#include "msg/Message.h"
#include "messages/MOSDPeeringOp.h"
#include "osd/PGPeeringEvent.h"

class MBackfillReserve : public MOSDPeeringOp {
private:
  static constexpr int HEAD_VERSION = 5;
  static constexpr int COMPAT_VERSION = 4;
public:
  spg_t pgid;
  epoch_t query_epoch;
  enum {
    REQUEST = 0,   // primary->replica: please reserve a slot
    GRANT = 1,     // replica->primary: ok, i reserved it
    REJECT_TOOFULL = 2,    // replica->primary: too full, sorry, try again later (*)
    RELEASE = 3,   // primary->replcia: release the slot i reserved before
    REVOKE_TOOFULL = 4,   // replica->primary: too full, stop backfilling
    REVOKE = 5,    // replica->primary: i'm taking back the slot i gave you
    // (*) NOTE: prior to luminous, REJECT was overloaded to also mean release
  };
  uint32_t type;
  uint32_t priority;
  int64_t primary_num_bytes;
  int64_t shard_num_bytes;

  spg_t get_spg() const {
    return pgid;
  }
  epoch_t get_map_epoch() const {
    return query_epoch;
  }
  epoch_t get_min_epoch() const {
    return query_epoch;
  }

  PGPeeringEvent *get_event() override {
    switch (type) {
    case REQUEST:
      return new PGPeeringEvent(
	query_epoch,
	query_epoch,
	RequestBackfillPrio(priority, primary_num_bytes, shard_num_bytes));
    case GRANT:
      return new PGPeeringEvent(
	query_epoch,
	query_epoch,
	RemoteBackfillReserved());
    case REJECT_TOOFULL:
      // NOTE: this is replica -> primary "i reject your request"
      //      and also primary -> replica "cancel my previously-granted request"
      //                                  (for older peers)
      //      and also replica -> primary "i revoke your reservation"
      //                                  (for older peers)
      return new PGPeeringEvent(
	query_epoch,
	query_epoch,
	RemoteReservationRejectedTooFull());
    case RELEASE:
      return new PGPeeringEvent(
	query_epoch,
	query_epoch,
	RemoteReservationCanceled());
    case REVOKE_TOOFULL:
      return new PGPeeringEvent(
	query_epoch,
	query_epoch,
	RemoteReservationRevokedTooFull());
    case REVOKE:
      return new PGPeeringEvent(
	query_epoch,
	query_epoch,
	RemoteReservationRevoked());
    default:
      ceph_abort();
    }
  }

  MBackfillReserve()
    : MOSDPeeringOp{MSG_OSD_BACKFILL_RESERVE, HEAD_VERSION, COMPAT_VERSION},
      query_epoch(0), type(-1), priority(-1), primary_num_bytes(0),
      shard_num_bytes(0) {}
  MBackfillReserve(int type,
		   spg_t pgid,
		   epoch_t query_epoch, unsigned prio = -1,
		   int64_t primary_num_bytes = 0,
                   int64_t shard_num_bytes = 0)
    : MOSDPeeringOp{MSG_OSD_BACKFILL_RESERVE, HEAD_VERSION, COMPAT_VERSION},
      pgid(pgid), query_epoch(query_epoch),
      type(type), priority(prio), primary_num_bytes(primary_num_bytes),
      shard_num_bytes(shard_num_bytes) {}

  std::string_view get_type_name() const override {
    return "MBackfillReserve";
  }

  void inner_print(std::ostream& out) const override {
    switch (type) {
    case REQUEST:
      out << "REQUEST";
      break;
    case GRANT:
      out << "GRANT";
      break;
    case REJECT_TOOFULL:
      out << "REJECT_TOOFULL";
      break;
    case RELEASE:
      out << "RELEASE";
      break;
    case REVOKE_TOOFULL:
      out << "REVOKE_TOOFULL";
      break;
    case REVOKE:
      out << "REVOKE";
      break;
    }
    if (type == REQUEST) out << " prio: " << priority;
    return;
  }

  void decode_payload() override {
    auto p = payload.cbegin();
    using ceph::decode;
    decode(pgid.pgid, p);
    decode(query_epoch, p);
    decode(type, p);
    decode(priority, p);
    decode(pgid.shard, p);
    if (header.version >= 5) {
      decode(primary_num_bytes, p);
      decode(shard_num_bytes, p);
    } else {
      primary_num_bytes = 0;
      shard_num_bytes = 0;
    }
  }

  void encode_payload(uint64_t features) override {
    using ceph::encode;
    if (!HAVE_FEATURE(features, RECOVERY_RESERVATION_2)) {
      header.version = 3;
      header.compat_version = 3;
      encode(pgid.pgid, payload);
      encode(query_epoch, payload);
      encode((type == RELEASE || type == REVOKE_TOOFULL || type == REVOKE) ?
	       REJECT_TOOFULL : type, payload);
      encode(priority, payload);
      encode(pgid.shard, payload);
      return;
    }
    header.version = HEAD_VERSION;
    header.compat_version = COMPAT_VERSION;
    encode(pgid.pgid, payload);
    encode(query_epoch, payload);
    encode(type, payload);
    encode(priority, payload);
    encode(pgid.shard, payload);
    encode(primary_num_bytes, payload);
    encode(shard_num_bytes, payload);
  }
};

#endif