src/store/Disk.h

   1 /*
   2  * Copyright (C) 1996-2016 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 class ConfigOption;
  16 class RemovalPolicy;
  17
  18 namespace Store {
  19
  20 /// manages a single cache_dir
  21 class Disk: public Controlled
  22 {
  23
  24 public:
  25     typedef RefCount<Disk> Pointer;
  26
  27     explicit Disk(char const *aType);
  28     virtual ~Disk();
  29     virtual void reconfigure() = 0;
  30     char const *type() const;
  31
  32     virtual bool needsDiskStrand() const; ///< needs a dedicated kid process
  33     virtual bool active() const; ///< may be used in this strand
  34     /// whether stat should be reported by this SwapDir
  35     virtual bool doReportStat() const { return active(); }
  36     /// whether SwapDir may benefit from unlinkd
  37     virtual bool unlinkdUseful() const = 0;
  38
  39     /**
  40      * Notify this disk that it is full.
  41      \todo XXX move into a protected api call between store files and their stores, rather than a top level api call
  42      */
  43     virtual void diskFull();
  44
  45     /* Controlled API */
  46     virtual void create() override;
  47     virtual StoreEntry *get(const cache_key *) override;
  48     virtual uint64_t maxSize() const override { return max_size; }
  49     virtual uint64_t minSize() const override;
  50     virtual int64_t maxObjectSize() const override;
  51     virtual void getStats(StoreInfoStats &stats) const override;
  52     virtual void stat(StoreEntry &) const override;
  53     virtual void reference(StoreEntry &e) override;
  54     virtual bool dereference(StoreEntry &e) override;
  55     virtual void maintain() override;
  56     virtual bool smpAware() const override { return false; }
  57
  58     /// the size of the smallest entry this cache_dir can store
  59     int64_t minObjectSize() const;
  60
  61     /// configure the maximum object size for this storage area.
  62     /// May be any size up to the total storage area.
  63     void maxObjectSize(int64_t newMax);
  64
  65     /// whether we can store an object of the given size
  66     /// negative objSize means the object size is currently unknown
  67     bool objectSizeIsAcceptable(int64_t objSize) const;
  68
  69     /// called when the entry is about to forget its association with cache_dir
  70     virtual void disconnect(StoreEntry &) {}
  71
  72     /// called when entry swap out is complete
  73     virtual void swappedOut(const StoreEntry &e) = 0;
  74
  75 protected:
  76     void parseOptions(int reconfiguring);
  77     void dumpOptions(StoreEntry * e) const;
  78     virtual ConfigOption *getOptionTree() const;
  79     virtual bool allowOptionReconfigure(const char *const) const { return true; }
  80
  81     int64_t sizeInBlocks(const int64_t size) const { return (size + fs.blksize - 1) / fs.blksize; }
  82
  83 private:
  84     bool optionReadOnlyParse(char const *option, const char *value, int reconfiguring);
  85     void optionReadOnlyDump(StoreEntry * e) const;
  86     bool optionObjectSizeParse(char const *option, const char *value, int reconfiguring);
  87     void optionObjectSizeDump(StoreEntry * e) const;
  88     char const *theType;
  89
  90 protected:
  91     uint64_t max_size;        ///< maximum allocatable size of the storage area
  92     int64_t min_objsize;      ///< minimum size of any object stored here (-1 for no limit)
  93     int64_t max_objsize;      ///< maximum size of any object stored here (-1 for no limit)
  94
  95 public:
  96     char *path;
  97     int index;          /* This entry's index into the swapDirs array */
  98     int disker; ///< disker kid id dedicated to this SwapDir or -1
  99     RemovalPolicy *repl;
 100     int removals;
 101     int scanned;
 102
 103     struct Flags {
 104         Flags() : selected(false), read_only(false) {}
 105         bool selected;
 106         bool read_only;
 107     } flags;
 108
 109     virtual void dump(StoreEntry &)const;   /* Dump fs config snippet */
 110     virtual bool doubleCheck(StoreEntry &); /* Double check the obj integrity */
 111     virtual void statfs(StoreEntry &) const;    /* Dump fs statistics */
 112
 113     /// check whether we can store the entry; if we can, report current load
 114     virtual bool canStore(const StoreEntry &e, int64_t diskSpaceNeeded, int &load) const = 0;
 115
 116     virtual StoreIOState::Pointer createStoreIO(StoreEntry &, StoreIOState::STFNCB *, StoreIOState::STIOCB *, void *) = 0;
 117     virtual StoreIOState::Pointer openStoreIO(StoreEntry &, StoreIOState::STFNCB *, StoreIOState::STIOCB *, void *) = 0;
 118
 119     bool canLog(StoreEntry const &e)const;
 120     virtual void openLog();
 121     virtual void closeLog();
 122     virtual void logEntry(const StoreEntry & e, int op) const;
 123
 124     class CleanLog
 125     {
 126
 127     public:
 128         virtual ~CleanLog() {}
 129
 130         virtual const StoreEntry *nextEntry() = 0;
 131         virtual void write(StoreEntry const &) = 0;
 132     };
 133
 134     CleanLog *cleanLog;
 135     virtual int writeCleanStart();
 136     virtual void writeCleanDone();
 137     virtual void parse(int index, char *path) = 0;
 138
 139     struct {
 140         int blksize;
 141     } fs;
 142 };
 143
 144 } // namespace Store
 145
 146 #endif /* SQUID_STORE_DISK_H */
 147