ceph/src/mds/JournalPointer.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 JOURNAL_POINTER_H
  17 #define JOURNAL_POINTER_H
  18
  19 #include "include/encoding.h"
  20 #include "mdstypes.h"
  21
  22 class Objecter;
  23 class Mutex;
  24
  25 // This always lives in the same location for a given MDS
  26 // instance, it tells the daemon where to look for the journal.
  27 class JournalPointer {
  28   // MDS rank
  29   int node_id;
  30   // Metadata pool ID
  31   int64_t pool_id;
  32
  33   std::string get_object_id() const;
  34
  35   public:
  36   // The currently active journal
  37   inodeno_t front;
  38   // The backup journal, if any (may be 0)
  39   inodeno_t back;
  40
  41   void encode(bufferlist &bl) const {
  42     ENCODE_START(1, 1, bl);
  43     ::encode(front, bl);
  44     ::encode(back, bl);
  45     ENCODE_FINISH(bl);
  46   }
  47
  48   void decode(bufferlist::iterator &bl) {
  49     DECODE_START(1, bl);
  50     ::decode(front, bl);
  51     ::decode(back, bl);
  52     DECODE_FINISH(bl);
  53   }
  54
  55   JournalPointer(int node_id_, int64_t pool_id_) : node_id(node_id_), pool_id(pool_id_),
  56     front(0), back(0) {}
  57
  58   JournalPointer() : node_id(-1), pool_id(-1), front(0), back(0) {}
  59
  60   int load(Objecter *objecter);
  61   int save(Objecter *objecter) const;
  62   void save(Objecter *objecter, Context *completion) const;
  63
  64   bool is_null() const {
  65     return front == 0 && back == 0;
  66   }
  67
  68   void dump(Formatter *f) const {
  69     f->open_object_section("journal_pointer");
  70     {
  71       f->dump_unsigned("front", front);
  72       f->dump_unsigned("back", back);
  73     }
  74     f->close_section(); // journal_header
  75   }
  76
  77   static void generate_test_instances(std::list<JournalPointer*> &ls)
  78   {
  79     ls.push_back(new JournalPointer());
  80     ls.push_back(new JournalPointer());
  81     ls.back()->front = 0xdeadbeef;
  82     ls.back()->back = 0xfeedbead;
  83   }
  84 };
  85 WRITE_CLASS_ENCODER(JournalPointer)
  86
  87 #endif // JOURNAL_POINTER_H