ceph/src/os/filestore/Journal.h

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3 /*
   4  * Ceph - scalable distributed file system
   5  *
   6  * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
   7  *
   8  * This is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License version 2.1, as published by the Free Software
  11  * Foundation.  See file COPYING.
  12  *
  13  */
  14
  15
  16 #ifndef CEPH_JOURNAL_H
  17 #define CEPH_JOURNAL_H
  18
  19 #include <errno.h>
  20
  21 #include "include/buffer_fwd.h"
  22 #include "include/Context.h"
  23 #include "common/Finisher.h"
  24 #include "common/TrackedOp.h"
  25 #include "os/ObjectStore.h"
  26 #include "common/zipkin_trace.h"
  27
  28 class PerfCounters;
  29
  30 class Journal {
  31 protected:
  32   uuid_d fsid;
  33   Finisher *finisher;
  34 public:
  35   CephContext* cct;
  36   PerfCounters *logger;
  37 protected:
  38   Cond *do_sync_cond;
  39   bool wait_on_full;
  40
  41 public:
  42   Journal(CephContext* cct, uuid_d f, Finisher *fin, Cond *c=0) :
  43     fsid(f), finisher(fin), cct(cct), logger(NULL),
  44     do_sync_cond(c),
  45     wait_on_full(false) { }
  46   virtual ~Journal() { }
  47
  48   virtual int check() = 0;   ///< check if journal appears valid
  49   virtual int create() = 0;  ///< create a fresh journal
  50   virtual int open(uint64_t fs_op_seq) = 0;  ///< open an existing journal
  51   virtual void close() = 0;  ///< close an open journal
  52
  53   virtual void flush() = 0;
  54
  55   /**
  56    * reserve_throttle_and_backoff
  57    *
  58    * Implementation may throttle or backoff based on ops
  59    * reserved here but not yet released using committed_thru.
  60    */
  61   virtual void reserve_throttle_and_backoff(uint64_t count) = 0;
  62
  63   virtual int dump(ostream& out) { return -EOPNOTSUPP; }
  64
  65   void set_wait_on_full(bool b) { wait_on_full = b; }
  66
  67   // writes
  68   virtual bool is_writeable() = 0;
  69   virtual int make_writeable() = 0;
  70   virtual void submit_entry(uint64_t seq, bufferlist& e, uint32_t orig_len,
  71                             Context *oncommit,
  72                             TrackedOpRef osd_op = TrackedOpRef()) = 0;
  73   virtual void commit_start(uint64_t seq) = 0;
  74   virtual void committed_thru(uint64_t seq) = 0;
  75
  76   /// Read next journal entry - asserts on invalid journal
  77   virtual bool read_entry(
  78     bufferlist &bl, ///< [out] payload on successful read
  79     uint64_t &seq   ///< [in,out] sequence number on last successful read
  80     ) = 0; ///< @return true on successful read, false on journal end
  81
  82   virtual bool should_commit_now() = 0;
  83
  84   virtual int prepare_entry(vector<ObjectStore::Transaction>& tls, bufferlist* tbl) = 0;
  85
  86   virtual off64_t get_journal_size_estimate() { return 0; }
  87
  88   // reads/recovery
  89
  90 };
  91
  92 #endif