src/fs/rock/RockRebuild.h

   1 /*
   2  * Copyright (C) 1996-2023 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #ifndef SQUID_SRC_FS_ROCK_ROCKREBUILD_H
  10 #define SQUID_SRC_FS_ROCK_ROCKREBUILD_H
  11
  12 #include "base/AsyncJob.h"
  13 #include "base/RunnersRegistry.h"
  14 #include "cbdata.h"
  15 #include "fs/rock/forward.h"
  16 #include "ipc/mem/Pointer.h"
  17 #include "ipc/StoreMap.h"
  18 #include "MemBuf.h"
  19 #include "store_rebuild.h"
  20
  21 namespace Rock
  22 {
  23
  24 class LoadingEntry;
  25 class LoadingSlot;
  26 class LoadingParts;
  27
  28 /// \ingroup Rock
  29 /// manages store rebuild process: loading meta information from db on disk
  30 class Rebuild: public AsyncJob, private IndependentRunner
  31 {
  32     CBDATA_CHILD(Rebuild);
  33
  34 public:
  35     /// cache_dir indexing statistics shared across same-kid process restarts
  36     class Stats
  37     {
  38     public:
  39         static SBuf Path(const char *dirPath);
  40         static Ipc::Mem::Owner<Stats> *Init(const SwapDir &);
  41
  42         static size_t SharedMemorySize() { return sizeof(Stats); }
  43         size_t sharedMemorySize() const { return SharedMemorySize(); }
  44
  45         /// whether the rebuild is finished already
  46         bool completed(const SwapDir &) const;
  47
  48         StoreRebuildData counts;
  49     };
  50
  51     /// starts indexing the given cache_dir if that indexing is necessary
  52     /// \returns whether the indexing was necessary (and, hence, started)
  53     static bool Start(SwapDir &dir);
  54
  55     /* AsyncJob API */
  56     virtual void callException(const std::exception &) override;
  57
  58 protected:
  59     /// whether the current kid is responsible for rebuilding the given cache_dir
  60     static bool IsResponsible(const SwapDir &);
  61
  62     Rebuild(SwapDir *dir, const Ipc::Mem::Pointer<Stats> &);
  63     ~Rebuild() override;
  64
  65     /* Registered Runner API */
  66     void startShutdown() override;
  67
  68     /* AsyncJob API */
  69     void start() override;
  70     bool doneAll() const override;
  71     void swanSong() override;
  72
  73     bool doneLoading() const;
  74     bool doneValidating() const;
  75
  76 private:
  77     void checkpoint();
  78     void steps();
  79     void loadingSteps();
  80     void validationSteps();
  81     void loadOneSlot();
  82     void validateOneEntry(const sfileno fileNo);
  83     void validateOneSlot(const SlotId slotId);
  84     bool importEntry(Ipc::StoreMapAnchor &anchor, const sfileno slotId, const DbCellHeader &header);
  85     void freeBadEntry(const sfileno fileno, const char *eDescription);
  86
  87     void failure(const char *msg, int errNo = 0);
  88
  89     LoadingEntry loadingEntry(const sfileno fileNo);
  90     void startNewEntry(const sfileno fileno, const SlotId slotId, const DbCellHeader &header);
  91     void primeNewEntry(Ipc::StoreMapAnchor &anchor, const sfileno fileno, const DbCellHeader &header);
  92     void finalizeOrFree(const sfileno fileNo, LoadingEntry &le);
  93     void finalizeOrThrow(const sfileno fileNo, LoadingEntry &le);
  94     void addSlotToEntry(const sfileno fileno, const SlotId slotId, const DbCellHeader &header);
  95     void useNewSlot(const SlotId slotId, const DbCellHeader &header);
  96
  97     LoadingSlot loadingSlot(const SlotId slotId);
  98     void mapSlot(const SlotId slotId, const DbCellHeader &header);
  99     void freeUnusedSlot(const SlotId slotId, const bool invalid);
 100     void freeSlot(const SlotId slotId, const bool invalid);
 101
 102     template <class SlotIdType>
 103     void chainSlots(SlotIdType &from, const SlotId to);
 104
 105     bool sameEntry(const sfileno fileno, const DbCellHeader &header) const;
 106
 107     SBuf progressDescription() const;
 108
 109     SwapDir *sd;
 110     LoadingParts *parts; ///< parts of store entries being loaded from disk
 111
 112     Ipc::Mem::Pointer<Stats> stats; ///< indexing statistics in shared memory
 113
 114     int64_t dbSize;
 115     int dbSlotSize; ///< the size of a db cell, including the cell header
 116     int64_t dbSlotLimit; ///< total number of db cells
 117     int64_t dbEntryLimit; ///< maximum number of entries that can be stored in db
 118
 119     int fd; // store db file descriptor
 120     int64_t dbOffset; // TODO: calculate in a method, using loadingPos
 121     int64_t loadingPos; ///< index of the db slot being loaded from disk now
 122     int64_t validationPos; ///< index of the loaded db slot being validated now
 123     MemBuf buf; ///< space to load current db slot (and entry metadata) into
 124
 125     StoreRebuildData &counts; ///< a reference to the shared memory counters
 126
 127     /// whether we have started indexing this cache_dir before,
 128     /// presumably in the previous process performing the same-kid role
 129     const bool resuming;
 130
 131     static void Steps(void *data);
 132 };
 133
 134 } // namespace Rock
 135
 136 #endif /* SQUID_SRC_FS_ROCK_ROCKREBUILD_H */
 137