Adding upstream version 18.2.2.upstream/18.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 687 insertions, 0 deletions

diff --git a/src/osd/ECBackend.h b/src/osd/ECBackend.h
new file mode 100644
index 000000000..d710aacb7
--- /dev/null
+++ b/src/osd/ECBackend.h
@@ -0,0 +1,687 @@
+// -*- 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) 2013 Inktank Storage, Inc.
+ *
+ * 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 ECBACKEND_H
+#define ECBACKEND_H
+
+#include <boost/intrusive/set.hpp>
+#include <boost/intrusive/list.hpp>
+
+#include "OSD.h"
+#include "PGBackend.h"
+#include "erasure-code/ErasureCodeInterface.h"
+#include "ECUtil.h"
+#include "ECTransaction.h"
+#include "ExtentCache.h"
+
+//forward declaration
+struct ECSubWrite;
+struct ECSubWriteReply;
+struct ECSubRead;
+struct ECSubReadReply;
+
+struct RecoveryMessages;
+class ECBackend : public PGBackend {
+public:
+  RecoveryHandle *open_recovery_op() override;
+
+  void run_recovery_op(
+    RecoveryHandle *h,
+    int priority
+    ) override;
+
+  int recover_object(
+    const hobject_t &hoid,
+    eversion_t v,
+    ObjectContextRef head,
+    ObjectContextRef obc,
+    RecoveryHandle *h
+    ) override;
+
+  bool _handle_message(
+    OpRequestRef op
+    ) override;
+  bool can_handle_while_inactive(
+    OpRequestRef op
+    ) override;
+  friend struct SubWriteApplied;
+  friend struct SubWriteCommitted;
+  void sub_write_committed(
+    ceph_tid_t tid,
+    eversion_t version,
+    eversion_t last_complete,
+    const ZTracer::Trace &trace);
+  void handle_sub_write(
+    pg_shard_t from,
+    OpRequestRef msg,
+    ECSubWrite &op,
+    const ZTracer::Trace &trace
+    );
+  void handle_sub_read(
+    pg_shard_t from,
+    const ECSubRead &op,
+    ECSubReadReply *reply,
+    const ZTracer::Trace &trace
+    );
+  void handle_sub_write_reply(
+    pg_shard_t from,
+    const ECSubWriteReply &op,
+    const ZTracer::Trace &trace
+    );
+  void handle_sub_read_reply(
+    pg_shard_t from,
+    ECSubReadReply &op,
+    RecoveryMessages *m,
+    const ZTracer::Trace &trace
+    );
+
+  /// @see ReadOp below
+  void check_recovery_sources(const OSDMapRef& osdmap) override;
+
+  void on_change() override;
+  void clear_recovery_state() override;
+
+  void dump_recovery_info(ceph::Formatter *f) const override;
+
+  void call_write_ordered(std::function<void(void)> &&cb) override;
+
+  void submit_transaction(
+    const hobject_t &hoid,
+    const object_stat_sum_t &delta_stats,
+    const eversion_t &at_version,
+    PGTransactionUPtr &&t,
+    const eversion_t &trim_to,
+    const eversion_t &min_last_complete_ondisk,
+    std::vector<pg_log_entry_t>&& log_entries,
+    std::optional<pg_hit_set_history_t> &hset_history,
+    Context *on_all_commit,
+    ceph_tid_t tid,
+    osd_reqid_t reqid,
+    OpRequestRef op
+    ) override;
+
+  int objects_read_sync(
+    const hobject_t &hoid,
+    uint64_t off,
+    uint64_t len,
+    uint32_t op_flags,
+    ceph::buffer::list *bl) override;
+
+  /**
+   * Async read mechanism
+   *
+   * Async reads use the same async read mechanism as does recovery.
+   * CallClientContexts is responsible for reconstructing the response
+   * buffer as well as for calling the callbacks.
+   *
+   * One tricky bit is that two reads may possibly not read from the same
+   * std::set of replicas.  This could result in two reads completing in the
+   * wrong (from the interface user's point of view) order.  Thus, we
+   * maintain a queue of in progress reads (@see in_progress_client_reads)
+   * to ensure that we always call the completion callback in order.
+   *
+   * Another subtly is that while we may read a degraded object, we will
+   * still only perform a client read from shards in the acting std::set.  This
+   * ensures that we won't ever have to restart a client initiated read in
+   * check_recovery_sources.
+   */
+  void objects_read_and_reconstruct(
+    const std::map<hobject_t, std::list<boost::tuple<uint64_t, uint64_t, uint32_t> >
+    > &reads,
+    bool fast_read,
+    GenContextURef<std::map<hobject_t,std::pair<int, extent_map> > &&> &&func);
+
+  friend struct CallClientContexts;
+  struct ClientAsyncReadStatus {
+    unsigned objects_to_read;
+    GenContextURef<std::map<hobject_t,std::pair<int, extent_map> > &&> func;
+    std::map<hobject_t,std::pair<int, extent_map> > results;
+    explicit ClientAsyncReadStatus(
+      unsigned objects_to_read,
+      GenContextURef<std::map<hobject_t,std::pair<int, extent_map> > &&> &&func)
+      : objects_to_read(objects_to_read), func(std::move(func)) {}
+    void complete_object(
+      const hobject_t &hoid,
+      int err,
+      extent_map &&buffers) {
+      ceph_assert(objects_to_read);
+      --objects_to_read;
+      ceph_assert(!results.count(hoid));
+      results.emplace(hoid, std::make_pair(err, std::move(buffers)));
+    }
+    bool is_complete() const {
+      return objects_to_read == 0;
+    }
+    void run() {
+      func.release()->complete(std::move(results));
+    }
+  };
+  std::list<ClientAsyncReadStatus> in_progress_client_reads;
+  void objects_read_async(
+    const hobject_t &hoid,
+    const std::list<std::pair<boost::tuple<uint64_t, uint64_t, uint32_t>,
+		    std::pair<ceph::buffer::list*, Context*> > > &to_read,
+    Context *on_complete,
+    bool fast_read = false) override;
+
+  template <typename Func>
+  void objects_read_async_no_cache(
+    const std::map<hobject_t,extent_set> &to_read,
+    Func &&on_complete) {
+    std::map<hobject_t,std::list<boost::tuple<uint64_t, uint64_t, uint32_t> > > _to_read;
+    for (auto &&hpair: to_read) {
+      auto &l = _to_read[hpair.first];
+      for (auto extent: hpair.second) {
+	l.emplace_back(extent.first, extent.second, 0);
+      }
+    }
+    objects_read_and_reconstruct(
+      _to_read,
+      false,
+      make_gen_lambda_context<
+      std::map<hobject_t,std::pair<int, extent_map> > &&, Func>(
+	  std::forward<Func>(on_complete)));
+  }
+  void kick_reads() {
+    while (in_progress_client_reads.size() &&
+	   in_progress_client_reads.front().is_complete()) {
+      in_progress_client_reads.front().run();
+      in_progress_client_reads.pop_front();
+    }
+  }
+
+private:
+  friend struct ECRecoveryHandle;
+  uint64_t get_recovery_chunk_size() const {
+    return round_up_to(cct->_conf->osd_recovery_max_chunk,
+			sinfo.get_stripe_width());
+  }
+
+  void get_want_to_read_shards(std::set<int> *want_to_read) const {
+    const std::vector<int> &chunk_mapping = ec_impl->get_chunk_mapping();
+    for (int i = 0; i < (int)ec_impl->get_data_chunk_count(); ++i) {
+      int chunk = (int)chunk_mapping.size() > i ? chunk_mapping[i] : i;
+      want_to_read->insert(chunk);
+    }
+  }
+
+  /**
+   * Recovery
+   *
+   * Recovery uses the same underlying read mechanism as client reads
+   * with the slight difference that recovery reads may come from non
+   * acting shards.  Thus, check_recovery_sources may wind up calling
+   * cancel_pull for a read originating with RecoveryOp.
+   *
+   * The recovery process is expressed as a state machine:
+   * - IDLE: Nothing is currently in progress, reads will be started and
+   *         we will transition to READING
+   * - READING: We are awaiting a pending read op.  Once complete, we will
+   *            decode the buffers and proceed to WRITING
+   * - WRITING: We are awaiting a completed push.  Once complete, we will
+   *            either transition to COMPLETE or to IDLE to continue.
+   * - COMPLETE: complete
+   *
+   * We use the existing Push and PushReply messages and structures to
+   * handle actually shuffling the data over to the replicas.  recovery_info
+   * and recovery_progress are expressed in terms of the logical offset
+   * space except for data_included which is in terms of the chunked object
+   * space (to match the passed buffer).
+   *
+   * xattrs are requested on the first read and used to initialize the
+   * object_context if missing on completion of the first read.
+   *
+   * In order to batch up reads and writes, we batch Push, PushReply,
+   * Transaction, and reads in a RecoveryMessages object which is passed
+   * among the recovery methods.
+   */
+  struct RecoveryOp {
+    hobject_t hoid;
+    eversion_t v;
+    std::set<pg_shard_t> missing_on;
+    std::set<shard_id_t> missing_on_shards;
+
+    ObjectRecoveryInfo recovery_info;
+    ObjectRecoveryProgress recovery_progress;
+
+    enum state_t { IDLE, READING, WRITING, COMPLETE } state;
+
+    static const char* tostr(state_t state) {
+      switch (state) {
+      case ECBackend::RecoveryOp::IDLE:
+	return "IDLE";
+      case ECBackend::RecoveryOp::READING:
+	return "READING";
+      case ECBackend::RecoveryOp::WRITING:
+	return "WRITING";
+      case ECBackend::RecoveryOp::COMPLETE:
+	return "COMPLETE";
+      default:
+	ceph_abort();
+	return "";
+      }
+    }
+
+    // must be filled if state == WRITING
+    std::map<int, ceph::buffer::list> returned_data;
+    std::map<std::string, ceph::buffer::list, std::less<>> xattrs;
+    ECUtil::HashInfoRef hinfo;
+    ObjectContextRef obc;
+    std::set<pg_shard_t> waiting_on_pushes;
+
+    // valid in state READING
+    std::pair<uint64_t, uint64_t> extent_requested;
+
+    void dump(ceph::Formatter *f) const;
+
+    RecoveryOp() : state(IDLE) {}
+  };
+  friend ostream &operator<<(ostream &lhs, const RecoveryOp &rhs);
+  std::map<hobject_t, RecoveryOp> recovery_ops;
+
+  void continue_recovery_op(
+    RecoveryOp &op,
+    RecoveryMessages *m);
+  void dispatch_recovery_messages(RecoveryMessages &m, int priority);
+  friend struct OnRecoveryReadComplete;
+  void handle_recovery_read_complete(
+    const hobject_t &hoid,
+    boost::tuple<uint64_t, uint64_t, std::map<pg_shard_t, ceph::buffer::list> > &to_read,
+    std::optional<std::map<std::string, ceph::buffer::list, std::less<>> > attrs,
+    RecoveryMessages *m);
+  void handle_recovery_push(
+    const PushOp &op,
+    RecoveryMessages *m,
+    bool is_repair);
+  void handle_recovery_push_reply(
+    const PushReplyOp &op,
+    pg_shard_t from,
+    RecoveryMessages *m);
+  void get_all_avail_shards(
+    const hobject_t &hoid,
+    const std::set<pg_shard_t> &error_shards,
+    std::set<int> &have,
+    std::map<shard_id_t, pg_shard_t> &shards,
+    bool for_recovery);
+
+public:
+  /**
+   * Low level async read mechanism
+   *
+   * To avoid duplicating the logic for requesting and waiting for
+   * multiple object shards, there is a common async read mechanism
+   * taking a std::map of hobject_t->read_request_t which defines callbacks
+   * taking read_result_ts as arguments.
+   *
+   * tid_to_read_map gives open read ops.  check_recovery_sources uses
+   * shard_to_read_map and ReadOp::source_to_obj to restart reads
+   * involving down osds.
+   *
+   * The user is responsible for specifying replicas on which to read
+   * and for reassembling the buffer on the other side since client
+   * reads require the original object buffer while recovery only needs
+   * the missing pieces.
+   *
+   * Rather than handling reads on the primary directly, we simply send
+   * ourselves a message.  This avoids a dedicated primary path for that
+   * part.
+   */
+  struct read_result_t {
+    int r;
+    std::map<pg_shard_t, int> errors;
+    std::optional<std::map<std::string, ceph::buffer::list, std::less<>> > attrs;
+    std::list<
+      boost::tuple<
+	uint64_t, uint64_t, std::map<pg_shard_t, ceph::buffer::list> > > returned;
+    read_result_t() : r(0) {}
+  };
+  struct read_request_t {
+    const std::list<boost::tuple<uint64_t, uint64_t, uint32_t> > to_read;
+    std::map<pg_shard_t, std::vector<std::pair<int, int>>> need;
+    bool want_attrs;
+    GenContext<std::pair<RecoveryMessages *, read_result_t& > &> *cb;
+    read_request_t(
+      const std::list<boost::tuple<uint64_t, uint64_t, uint32_t> > &to_read,
+      const std::map<pg_shard_t, std::vector<std::pair<int, int>>> &need,
+      bool want_attrs,
+      GenContext<std::pair<RecoveryMessages *, read_result_t& > &> *cb)
+      : to_read(to_read), need(need), want_attrs(want_attrs),
+	cb(cb) {}
+  };
+  friend ostream &operator<<(ostream &lhs, const read_request_t &rhs);
+
+  struct ReadOp {
+    int priority;
+    ceph_tid_t tid;
+    OpRequestRef op; // may be null if not on behalf of a client
+    // True if redundant reads are issued, false otherwise,
+    // this is useful to tradeoff some resources (redundant ops) for
+    // low latency read, especially on relatively idle cluster
+    bool do_redundant_reads;
+    // True if reading for recovery which could possibly reading only a subset
+    // of the available shards.
+    bool for_recovery;
+
+    ZTracer::Trace trace;
+
+    std::map<hobject_t, std::set<int>> want_to_read;
+    std::map<hobject_t, read_request_t> to_read;
+    std::map<hobject_t, read_result_t> complete;
+
+    std::map<hobject_t, std::set<pg_shard_t>> obj_to_source;
+    std::map<pg_shard_t, std::set<hobject_t> > source_to_obj;
+
+    void dump(ceph::Formatter *f) const;
+
+    std::set<pg_shard_t> in_progress;
+
+    ReadOp(
+      int priority,
+      ceph_tid_t tid,
+      bool do_redundant_reads,
+      bool for_recovery,
+      OpRequestRef op,
+      std::map<hobject_t, std::set<int>> &&_want_to_read,
+      std::map<hobject_t, read_request_t> &&_to_read)
+      : priority(priority), tid(tid), op(op), do_redundant_reads(do_redundant_reads),
+	for_recovery(for_recovery), want_to_read(std::move(_want_to_read)),
+	to_read(std::move(_to_read)) {
+      for (auto &&hpair: to_read) {
+	auto &returned = complete[hpair.first].returned;
+	for (auto &&extent: hpair.second.to_read) {
+	  returned.push_back(
+	    boost::make_tuple(
+	      extent.get<0>(),
+	      extent.get<1>(),
+	      std::map<pg_shard_t, ceph::buffer::list>()));
+	}
+      }
+    }
+    ReadOp() = delete;
+    ReadOp(const ReadOp &) = default;
+    ReadOp(ReadOp &&) = default;
+  };
+  friend struct FinishReadOp;
+  void filter_read_op(
+    const OSDMapRef& osdmap,
+    ReadOp &op);
+  void complete_read_op(ReadOp &rop, RecoveryMessages *m);
+  friend ostream &operator<<(ostream &lhs, const ReadOp &rhs);
+  std::map<ceph_tid_t, ReadOp> tid_to_read_map;
+  std::map<pg_shard_t, std::set<ceph_tid_t> > shard_to_read_map;
+  void start_read_op(
+    int priority,
+    std::map<hobject_t, std::set<int>> &want_to_read,
+    std::map<hobject_t, read_request_t> &to_read,
+    OpRequestRef op,
+    bool do_redundant_reads, bool for_recovery);
+
+  void do_read_op(ReadOp &rop);
+  int send_all_remaining_reads(
+    const hobject_t &hoid,
+    ReadOp &rop);
+
+
+  /**
+   * Client writes
+   *
+   * ECTransaction is responsible for generating a transaction for
+   * each shard to which we need to send the write.  As required
+   * by the PGBackend interface, the ECBackend write mechanism
+   * passes trim information with the write and last_complete back
+   * with the reply.
+   *
+   * As with client reads, there is a possibility of out-of-order
+   * completions. Thus, callbacks and completion are called in order
+   * on the writing std::list.
+   */
+  struct Op : boost::intrusive::list_base_hook<> {
+    /// From submit_transaction caller, describes operation
+    hobject_t hoid;
+    object_stat_sum_t delta_stats;
+    eversion_t version;
+    eversion_t trim_to;
+    std::optional<pg_hit_set_history_t> updated_hit_set_history;
+    std::vector<pg_log_entry_t> log_entries;
+    ceph_tid_t tid;
+    osd_reqid_t reqid;
+    ZTracer::Trace trace;
+
+    eversion_t roll_forward_to; /// Soon to be generated internally
+
+    /// Ancillary also provided from submit_transaction caller
+    std::map<hobject_t, ObjectContextRef> obc_map;
+
+    /// see call_write_ordered
+    std::list<std::function<void(void)> > on_write;
+
+    /// Generated internally
+    std::set<hobject_t> temp_added;
+    std::set<hobject_t> temp_cleared;
+
+    ECTransaction::WritePlan plan;
+    bool requires_rmw() const { return !plan.to_read.empty(); }
+    bool invalidates_cache() const { return plan.invalidates_cache; }
+
+    // must be true if requires_rmw(), must be false if invalidates_cache()
+    bool using_cache = true;
+
+    /// In progress read state;
+    std::map<hobject_t,extent_set> pending_read; // subset already being read
+    std::map<hobject_t,extent_set> remote_read;  // subset we must read
+    std::map<hobject_t,extent_map> remote_read_result;
+    bool read_in_progress() const {
+      return !remote_read.empty() && remote_read_result.empty();
+    }
+
+    /// In progress write state.
+    std::set<pg_shard_t> pending_commit;
+    // we need pending_apply for pre-mimic peers so that we don't issue a
+    // read on a remote shard before it has applied a previous write.  We can
+    // remove this after nautilus.
+    std::set<pg_shard_t> pending_apply;
+    bool write_in_progress() const {
+      return !pending_commit.empty() || !pending_apply.empty();
+    }
+
+    /// optional, may be null, for tracking purposes
+    OpRequestRef client_op;
+
+    /// pin for cache
+    ExtentCache::write_pin pin;
+
+    /// Callbacks
+    Context *on_all_commit = nullptr;
+    ~Op() {
+      delete on_all_commit;
+    }
+  };
+  using op_list = boost::intrusive::list<Op>;
+  friend ostream &operator<<(ostream &lhs, const Op &rhs);
+
+  ExtentCache cache;
+  std::map<ceph_tid_t, Op> tid_to_op_map; /// Owns Op structure
+
+  /**
+   * We model the possible rmw states as a std::set of waitlists.
+   * All writes at this time complete in order, so a write blocked
+   * at waiting_state blocks all writes behind it as well (same for
+   * other states).
+   *
+   * Future work: We can break this up into a per-object pipeline
+   * (almost).  First, provide an ordering token to submit_transaction
+   * and require that all operations within a single transaction take
+   * place on a subset of hobject_t space partitioned by that token
+   * (the hashid seem about right to me -- even works for temp objects
+   * if you recall that a temp object created for object head foo will
+   * only ever be referenced by other transactions on foo and aren't
+   * reused).  Next, factor this part into a class and maintain one per
+   * ordering token.  Next, fixup PrimaryLogPG's repop queue to be
+   * partitioned by ordering token.  Finally, refactor the op pipeline
+   * so that the log entries passed into submit_transaction aren't
+   * versioned.  We can't assign versions to them until we actually
+   * submit the operation.  That's probably going to be the hard part.
+   */
+  class pipeline_state_t {
+    enum {
+      CACHE_VALID = 0,
+      CACHE_INVALID = 1
+    } pipeline_state = CACHE_VALID;
+  public:
+    bool caching_enabled() const {
+      return pipeline_state == CACHE_VALID;
+    }
+    bool cache_invalid() const {
+      return !caching_enabled();
+    }
+    void invalidate() {
+      pipeline_state = CACHE_INVALID;
+    }
+    void clear() {
+      pipeline_state = CACHE_VALID;
+    }
+    friend ostream &operator<<(ostream &lhs, const pipeline_state_t &rhs);
+  } pipeline_state;
+
+
+  op_list waiting_state;        /// writes waiting on pipe_state
+  op_list waiting_reads;        /// writes waiting on partial stripe reads
+  op_list waiting_commit;       /// writes waiting on initial commit
+  eversion_t completed_to;
+  eversion_t committed_to;
+  void start_rmw(Op *op, PGTransactionUPtr &&t);
+  bool try_state_to_reads();
+  bool try_reads_to_commit();
+  bool try_finish_rmw();
+  void check_ops();
+
+  ceph::ErasureCodeInterfaceRef ec_impl;
+
+
+  /**
+   * ECRecPred
+   *
+   * Determines the whether _have is sufficient to recover an object
+   */
+  class ECRecPred : public IsPGRecoverablePredicate {
+    std::set<int> want;
+    ceph::ErasureCodeInterfaceRef ec_impl;
+  public:
+    explicit ECRecPred(ceph::ErasureCodeInterfaceRef ec_impl) : ec_impl(ec_impl) {
+      for (unsigned i = 0; i < ec_impl->get_chunk_count(); ++i) {
+	want.insert(i);
+      }
+    }
+    bool operator()(const std::set<pg_shard_t> &_have) const override {
+      std::set<int> have;
+      for (std::set<pg_shard_t>::const_iterator i = _have.begin();
+	   i != _have.end();
+	   ++i) {
+	have.insert(i->shard);
+      }
+      std::map<int, std::vector<std::pair<int, int>>> min;
+      return ec_impl->minimum_to_decode(want, have, &min) == 0;
+    }
+  };
+  IsPGRecoverablePredicate *get_is_recoverable_predicate() const override {
+    return new ECRecPred(ec_impl);
+  }
+
+  int get_ec_data_chunk_count() const override {
+    return ec_impl->get_data_chunk_count();
+  }
+  int get_ec_stripe_chunk_size() const override {
+    return sinfo.get_chunk_size();
+  }
+
+  /**
+   * ECReadPred
+   *
+   * Determines the whether _have is sufficient to read an object
+   */
+  class ECReadPred : public IsPGReadablePredicate {
+    pg_shard_t whoami;
+    ECRecPred rec_pred;
+  public:
+    ECReadPred(
+      pg_shard_t whoami,
+      ceph::ErasureCodeInterfaceRef ec_impl) : whoami(whoami), rec_pred(ec_impl) {}
+    bool operator()(const std::set<pg_shard_t> &_have) const override {
+      return _have.count(whoami) && rec_pred(_have);
+    }
+  };
+  IsPGReadablePredicate *get_is_readable_predicate() const override {
+    return new ECReadPred(get_parent()->whoami_shard(), ec_impl);
+  }
+
+
+  const ECUtil::stripe_info_t sinfo;
+  /// If modified, ensure that the ref is held until the update is applied
+  SharedPtrRegistry<hobject_t, ECUtil::HashInfo> unstable_hashinfo_registry;
+  ECUtil::HashInfoRef get_hash_info(const hobject_t &hoid, bool create = false,
+				    const std::map<std::string, ceph::buffer::ptr, std::less<>> *attr = NULL);
+
+public:
+  ECBackend(
+    PGBackend::Listener *pg,
+    const coll_t &coll,
+    ObjectStore::CollectionHandle &ch,
+    ObjectStore *store,
+    CephContext *cct,
+    ceph::ErasureCodeInterfaceRef ec_impl,
+    uint64_t stripe_width);
+
+  /// Returns to_read replicas sufficient to reconstruct want
+  int get_min_avail_to_read_shards(
+    const hobject_t &hoid,     ///< [in] object
+    const std::set<int> &want,      ///< [in] desired shards
+    bool for_recovery,         ///< [in] true if we may use non-acting replicas
+    bool do_redundant_reads,   ///< [in] true if we want to issue redundant reads to reduce latency
+    std::map<pg_shard_t, std::vector<std::pair<int, int>>> *to_read   ///< [out] shards, corresponding subchunks to read
+    ); ///< @return error code, 0 on success
+
+  int get_remaining_shards(
+    const hobject_t &hoid,
+    const std::set<int> &avail,
+    const std::set<int> &want,
+    const read_result_t &result,
+    std::map<pg_shard_t, std::vector<std::pair<int, int>>> *to_read,
+    bool for_recovery);
+
+  int objects_get_attrs(
+    const hobject_t &hoid,
+    std::map<std::string, ceph::buffer::list, std::less<>> *out) override;
+
+  void rollback_append(
+    const hobject_t &hoid,
+    uint64_t old_size,
+    ObjectStore::Transaction *t) override;
+
+  bool auto_repair_supported() const override { return true; }
+
+  int be_deep_scrub(
+    const hobject_t &poid,
+    ScrubMap &map,
+    ScrubMapBuilder &pos,
+    ScrubMap::object &o) override;
+
+  uint64_t be_get_ondisk_size(uint64_t logical_size) const final {
+    return sinfo.logical_to_next_chunk_offset(logical_size);
+  }
+  void _failed_push(const hobject_t &hoid,
+    std::pair<RecoveryMessages *, ECBackend::read_result_t &> &in);
+};
+ostream &operator<<(ostream &lhs, const ECBackend::pipeline_state_t &rhs);
+
+#endif