src/store/Disk.h

   1 /*
   2  * Copyright (C) 1996-2015 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_STORE_DISK_H
  10 #define SQUID_STORE_DISK_H
  11
  12 #include "store/Controlled.h"
  13 #include "StoreIOState.h"
  14
  15
  16 class ConfigOption;
  17 class RemovalPolicy;
  18
  19 namespace Store {
  20
  21 /// manages a single cache_dir
  22 class Disk: public Controlled
  23 {
  24
  25 public:
  26     typedef RefCount<Disk> Pointer;
  27
  28     explicit Disk(char const *aType);
  29     virtual ~Disk();
  30     virtual void reconfigure() = 0;
  31     char const *type() const;
  32
  33     virtual bool needsDiskStrand() const; ///< needs a dedicated kid process
  34     virtual bool active() const; ///< may be used in this strand
  35     /// whether stat should be reported by this SwapDir
  36     virtual bool doReportStat() const { return active(); }
  37     /// whether SwapDir may benefit from unlinkd
  38     virtual bool unlinkdUseful() const = 0;
  39
  40     /**
  41      * Notify this disk that it is full.
  42      \todo XXX move into a protected api call between store files and their stores, rather than a top level api call
  43      */
  44     virtual void diskFull();
  45
  46     /* Controlled API */
  47     virtual void create() override;
  48     virtual StoreEntry *get(const cache_key *) override;
  49     virtual uint64_t maxSize() const override { return max_size; }
  50     virtual uint64_t minSize() const override;
  51     virtual int64_t maxObjectSize() const override;
  52     virtual void getStats(StoreInfoStats &stats) const override;
  53     virtual void stat(StoreEntry &) const override;
  54     virtual void reference(StoreEntry &e) override;
  55     virtual bool dereference(StoreEntry &e) override;
  56     virtual void maintain() override;
  57
  58     /// configure the maximum object size for this storage area.
  59     /// May be any size up to the total storage area.
  60     void maxObjectSize(int64_t newMax);
  61
  62     /// whether we can store an object of the given size
  63     /// negative objSize means the object size is currently unknown
  64     bool objectSizeIsAcceptable(int64_t objSize) const;
  65
  66     /// called when the entry is about to forget its association with cache_dir
  67     virtual void disconnect(StoreEntry &) {}
  68
  69     /// called when entry swap out is complete
  70     virtual void swappedOut(const StoreEntry &e) = 0;
  71
  72 protected:
  73     void parseOptions(int reconfiguring);
  74     void dumpOptions(StoreEntry * e) const;
  75     virtual ConfigOption *getOptionTree() const;
  76     virtual bool allowOptionReconfigure(const char *const) const { return true; }
  77
  78     int64_t sizeInBlocks(const int64_t size) const { return (size + fs.blksize - 1) / fs.blksize; }
  79
  80 private:
  81     bool optionReadOnlyParse(char const *option, const char *value, int reconfiguring);
  82     void optionReadOnlyDump(StoreEntry * e) const;
  83     bool optionObjectSizeParse(char const *option, const char *value, int reconfiguring);
  84     void optionObjectSizeDump(StoreEntry * e) const;
  85     char const *theType;
  86
  87 protected:
  88     uint64_t max_size;        ///< maximum allocatable size of the storage area
  89     int64_t min_objsize;      ///< minimum size of any object stored here (-1 for no limit)
  90     int64_t max_objsize;      ///< maximum size of any object stored here (-1 for no limit)
  91
  92 public:
  93     char *path;
  94     int index;          /* This entry's index into the swapDirs array */
  95     int disker; ///< disker kid id dedicated to this SwapDir or -1
  96     RemovalPolicy *repl;
  97     int removals;
  98     int scanned;
  99
 100     struct Flags {
 101         Flags() : selected(false), read_only(false) {}
 102         bool selected;
 103         bool read_only;
 104     } flags;
 105
 106     virtual void dump(StoreEntry &)const;   /* Dump fs config snippet */
 107     virtual bool doubleCheck(StoreEntry &); /* Double check the obj integrity */
 108     virtual void statfs(StoreEntry &) const;    /* Dump fs statistics */
 109
 110     /// check whether we can store the entry; if we can, report current load
 111     virtual bool canStore(const StoreEntry &e, int64_t diskSpaceNeeded, int &load) const = 0;
 112
 113     virtual StoreIOState::Pointer createStoreIO(StoreEntry &, StoreIOState::STFNCB *, StoreIOState::STIOCB *, void *) = 0;
 114     virtual StoreIOState::Pointer openStoreIO(StoreEntry &, StoreIOState::STFNCB *, StoreIOState::STIOCB *, void *) = 0;
 115
 116     bool canLog(StoreEntry const &e)const;
 117     virtual void openLog();
 118     virtual void closeLog();
 119     virtual void logEntry(const StoreEntry & e, int op) const;
 120
 121     class CleanLog
 122     {
 123
 124     public:
 125         virtual ~CleanLog() {}
 126
 127         virtual const StoreEntry *nextEntry() = 0;
 128         virtual void write(StoreEntry const &) = 0;
 129     };
 130
 131     CleanLog *cleanLog;
 132     virtual int writeCleanStart();
 133     virtual void writeCleanDone();
 134     virtual void parse(int index, char *path) = 0;
 135
 136     struct {
 137         int blksize;
 138     } fs;
 139 };
 140
 141 } // namespace Store
 142
 143 #endif /* SQUID_STORE_DISK_H */
 144