ceph/src/os/filestore/IndexManager.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 #ifndef OS_INDEXMANAGER_H
  15 #define OS_INDEXMANAGER_H
  16
  17 #include "include/unordered_map.h"
  18
  19 #include "common/ceph_mutex.h"
  20 #include "common/Cond.h"
  21 #include "common/config.h"
  22 #include "common/debug.h"
  23
  24 #include "CollectionIndex.h"
  25 #include "HashIndex.h"
  26
  27
  28 /// Public type for Index
  29 struct Index {
  30   CollectionIndex *index;
  31
  32   Index() : index(NULL) {}
  33   explicit Index(CollectionIndex* index) : index(index) {}
  34
  35   CollectionIndex *operator->() { return index; }
  36   CollectionIndex &operator*() { return *index; }
  37 };
  38
  39
  40 /**
  41  * Encapsulates mutual exclusion for CollectionIndexes.
  42  *
  43  * Allowing a modification (removal or addition of an object) to occur
  44  * while a read is occurring (lookup of an object's path and use of
  45  * that path) may result in the path becoming invalid.  Thus, during
  46  * the lifetime of a CollectionIndex object and any paths returned
  47  * by it, no other concurrent accesses may be allowed.
  48  * This is enforced by using CollectionIndex::access_lock
  49  */
  50 class IndexManager {
  51   CephContext* cct;
  52   /// Lock for Index Manager
  53   ceph::shared_mutex lock = ceph::make_shared_mutex("IndexManager lock");
  54   bool upgrade;
  55   ceph::unordered_map<coll_t, CollectionIndex* > col_indices;
  56
  57   /**
  58    * Index factory
  59    *
  60    * Encapsulates logic for handling legacy FileStore
  61    * layouts
  62    *
  63    * @param [in] c Collection for which to get index
  64    * @param [in] path Path to collection
  65    * @param [out] index Index for c
  66    * @return error code
  67    */
  68   int build_index(coll_t c, const char *path, CollectionIndex **index);
  69   bool get_index_optimistic(coll_t c, Index *index);
  70 public:
  71   /// Constructor
  72   explicit IndexManager(CephContext* cct,
  73                         bool upgrade) : cct(cct),
  74                                         upgrade(upgrade) {}
  75
  76   ~IndexManager();
  77
  78   /**
  79    * Reserve and return index for c
  80    *
  81    * @param [in] c Collection for which to get index
  82    * @param [in] baseDir base directory of collections
  83    * @param [out] index Index for c
  84    * @return error code
  85    */
  86   int get_index(coll_t c, const std::string& baseDir, Index *index);
  87
  88   /**
  89    * Initialize index for collection c at path
  90    *
  91    * @param [in] c Collection for which to init Index
  92    * @param [in] path Path to collection
  93    * @param [in] filestore_version version of containing FileStore
  94    * @return error code
  95    */
  96   int init_index(coll_t c, const char *path, uint32_t filestore_version);
  97 };
  98
  99 #endif