add policy cache for 'open'

A fusepath -> basepath cache for `open` to limit the overhead of FUSE in 'open, read/write, close' patterns (such as Transmission).

README.md

@@ -84,6 +84,7 @@ mergerfs does **not** support the copy-on-write (CoW) behavior found in **aufs**
 * **fsname=name**: sets the name of the filesystem as seen in **mount**, **df**, etc. Defaults to a list of the source paths concatenated together with the longest common prefix removed.
 * **func.<func>=<policy>**: sets the specific FUSE function's policy. See below for the list of value types. Example: **func.getattr=newest**
 * **category.<category>=<policy>**: Sets policy of all FUSE functions in the provided category. Example: **category.create=mfs**
+* **cache.open=<int>**: 'open' policy cache timeout in seconds. (default: 0)
 
 **NOTE:** Options are evaluated in the order listed so if the options are **func.rmdir=rand,category.action=ff** the **action** category setting will override the **rmdir** setting.
 
@@ -491,6 +492,15 @@ It's a difficult balance between memory usage, cache bloat & duplication, and pe
 Given the relatively high cost of FUSE due to the kernel <-> userspace round trips there are kernel side caches for file entries and attributes. The entry cache limits the `lookup` calls to mergerfs which ask if a file exists. The attribute cache limits the need to make `getattr` calls to mergerfs which provide file attributes (mode, size, type, etc.). As with the page cache these should not be used if the underlying filesystems are being manipulated at the same time as it could lead to odd behavior or data corruption. The options for setting these are `entry_timeout` and `negative_timeout` for the entry cache and `attr_timeout` for the attributes cache. `negative_timeout` refers to the timeout for negative responses to lookups (non-existant files).
 
 
+#### policy caching
+
+Policies are run every time a function is called. These policies can be expensive depending on the setup and usage patterns. Generally we wouldn't want to cache policy results because it may result in stale responses if the underlying drives are used directly.
+
+The `open` policy cache will cache the result of an `open` policy for a particular input for `cache.open` seconds or until the file is unlinked. Each file close (release) will randomly chose to clean up the cache of expired entries.
+
+This cache is useful in cases like that of **Transmission** which has a "open, read/write, close" pattern (which is much more costly due to the FUSE overhead than normal.)
+
+
 #### writeback caching
 
 writeback caching is a technique for improving write speeds by batching writes at a faster device and then bulk writing to the slower device. With FUSE the kernel will wait for a number of writes to be made and then send it to the filesystem as one request. mergerfs currently uses a slightly modified and vendored libfuse 2.9.7 which does not support writeback caching. However, a prototype port to libfuse 3.x has been made and the writeback cache appears to work as expected (though performance improvements greatly depend on the way the client app writes data). Once the port is complete and thoroughly tested writeback caching will be available.

libfuse/configure.ac

@@ -1,4 +1,4 @@
-AC_INIT(fuse, 2.9.8-mergerfs)
+AC_INIT(fuse, 2.9.7-mergerfs_2.26.0)
 
 AC_PREREQ(2.59d)
 AC_CONFIG_MACRO_DIR([m4])

man/mergerfs.1

@@ -211,6 +211,9 @@ Example: \f[B]func.getattr=newest\f[]
 \f[B]category.<category>=<policy>\f[]: Sets policy of all FUSE functions
 in the provided category.
 Example: \f[B]category.create=mfs\f[]
+.IP \[bu] 2
+\f[B]cache.open=\f[]: \[aq]open\[aq] policy cache timeout in seconds.
+(default: 0)
 .PP
 \f[B]NOTE:\f[] Options are evaluated in the order listed so if the
 options are \f[B]func.rmdir=rand,category.action=ff\f[] the
@@ -1034,6 +1037,23 @@ The options for setting these are \f[C]entry_timeout\f[] and
 for the attributes cache.
 \f[C]negative_timeout\f[] refers to the timeout for negative responses
 to lookups (non\-existant files).
+.SS policy caching
+.PP
+Policies are run every time a function is called.
+These policies can be expensive depending on the setup and usage
+patterns.
+Generally we wouldn\[aq]t want to cache policy results because it may
+result in stale responses if the underlying drives are used directly.
+.PP
+The \f[C]open\f[] policy cache will cache the result of an \f[C]open\f[]
+policy for a particular input for \f[C]cache.open\f[] seconds or until
+the file is unlinked.
+Each file close (release) will randomly chose to clean up the cache of
+expired entries.
+.PP
+This cache is useful in cases like that of \f[B]Transmission\f[] which
+has a "open, read/write, close" pattern (which is much more costly due
+to the FUSE overhead than normal.)
 .SS writeback caching
 .PP
 writeback caching is a technique for improving write speeds by batching

src/access.cpp

@@ -26,8 +26,6 @@
 
 using std::string;
 using std::vector;
-using mergerfs::Policy;
-using mergerfs::Category;
 
 static
 int

src/category.cpp

@@ -22,41 +22,38 @@
 
 #define CATEGORY(X) Category(Category::Enum::X,#X)
 
-namespace mergerfs
+const std::vector<Category> Category::_categories_ =
+  buildvector<Category,true>
+  (CATEGORY(invalid))
+  (CATEGORY(action))
+  (CATEGORY(create))
+  (CATEGORY(search));
+
+const Category * const Category::categories = &_categories_[1];
+
+const Category &Category::invalid = Category::categories[Category::Enum::invalid];
+const Category &Category::action  = Category::categories[Category::Enum::action];
+const Category &Category::create  = Category::categories[Category::Enum::create];
+const Category &Category::search  = Category::categories[Category::Enum::search];
+
+const Category&
+Category::find(const std::string &str)
 {
-  const std::vector<Category> Category::_categories_ =
-    buildvector<Category,true>
-    (CATEGORY(invalid))
-    (CATEGORY(action))
-    (CATEGORY(create))
-    (CATEGORY(search));
-
-  const Category * const Category::categories = &_categories_[1];
-
-  const Category &Category::invalid = Category::categories[Category::Enum::invalid];
-  const Category &Category::action  = Category::categories[Category::Enum::action];
-  const Category &Category::create  = Category::categories[Category::Enum::create];
-  const Category &Category::search  = Category::categories[Category::Enum::search];
-
-  const Category&
-  Category::find(const std::string &str)
-  {
-    for(int i = Enum::BEGIN; i != Enum::END; ++i)
-      {
-        if(categories[i] == str)
-          return categories[i];
-      }
-
-    return invalid;
-  }
-
-  const Category&
-  Category::find(const Category::Enum::Type i)
-  {
-    if(i >= Category::Enum::BEGIN &&
-       i  < Category::Enum::END)
-      return categories[i];
-
-    return invalid;
-  }
+  for(int i = Enum::BEGIN; i != Enum::END; ++i)
+    {
+      if(categories[i] == str)
+        return categories[i];
+    }
+
+  return invalid;
+}
+
+const Category&
+Category::find(const Category::Enum::Type i)
+{
+  if(i >= Category::Enum::BEGIN &&
+     i  < Category::Enum::END)
+    return categories[i];
+
+  return invalid;
 }

src/category.hpp

@@ -19,69 +19,66 @@
 #include <string>
 #include <vector>
 
-namespace mergerfs
+class Category
 {
-  class Category
+public:
+  struct Enum
   {
-  public:
-    struct Enum
-    {
-      enum Type
-        {
-          invalid = -1,
-          BEGIN   = 0,
-          action  = BEGIN,
-          create,
-          search,
-          END
-        };
-    };
+    enum Type
+      {
+        invalid = -1,
+        BEGIN   = 0,
+        action  = BEGIN,
+        create,
+        search,
+        END
+      };
+  };
 
-  private:
-    Enum::Type  _enum;
-    std::string _str;
+private:
+  Enum::Type  _enum;
+  std::string _str;
 
-  public:
-    Category()
-      : _enum(invalid),
-        _str(invalid)
-    {
-    }
+public:
+  Category()
+    : _enum(invalid),
+      _str(invalid)
+  {
+  }
 
-    Category(const Enum::Type   enum_,
-             const std::string &str_)
-      : _enum(enum_),
-        _str(str_)
-    {
-    }
+  Category(const Enum::Type   enum_,
+           const std::string &str_)
+    : _enum(enum_),
+      _str(str_)
+  {
+  }
 
-  public:
-    operator const Enum::Type() const { return _enum; }
-    operator const std::string&() const { return _str; }
-    operator const Category*() const { return this; }
+public:
+  operator const Enum::Type() const { return _enum; }
+  operator const std::string&() const { return _str; }
+  operator const Category*() const { return this; }
 
-    bool operator==(const std::string &str_) const
-    { return _str == str_; }
+  bool operator==(const std::string &str_) const
+  { return _str == str_; }
 
-    bool operator==(const Enum::Type enum_) const
-    { return _enum == enum_; }
+  bool operator==(const Enum::Type enum_) const
+  { return _enum == enum_; }
 
-    bool operator!=(const Category &r) const
-    { return _enum != r._enum; }
+  bool operator!=(const Category &r) const
+  { return _enum != r._enum; }
 
-    bool operator<(const Category &r) const
-    { return _enum < r._enum; }
+  bool operator<(const Category &r) const
+  { return _enum < r._enum; }
 
-  public:
-    static const Category &find(const std::string&);
-    static const Category &find(const Enum::Type);
+public:
+  static const Category &find(const std::string&);
+  static const Category &find(const Enum::Type);
 
-  public:
-    static const std::vector<Category>  _categories_;
-    static const Category * const       categories;
-    static const Category              &invalid;
-    static const Category              &action;
-    static const Category              &create;
-    static const Category              &search;
-  };
-}
+public:
+  static const std::vector<Category>  _categories_;
+  static const Category * const       categories;
+  static const Category              &invalid;
+  static const Category              &action;
+  static const Category              &create;
+  static const Category              &search;
+};

src/chmod.cpp

@@ -29,7 +29,6 @@
 
 using std::string;
 using std::vector;
-using mergerfs::Policy;
 
 static
 int

src/chown.cpp

@@ -29,7 +29,6 @@
 
 using std::string;
 using std::vector;
-using mergerfs::Policy;
 using mergerfs::Config;
 
 static

src/config.hpp

@@ -19,6 +19,7 @@
 #include "branch.hpp"
 #include "fusefunc.hpp"
 #include "policy.hpp"
+#include "policy_cache.hpp"
 
 #include <fuse.h>
 
@@ -102,6 +103,9 @@ namespace mergerfs
     const Policy *&unlink;
     const Policy *&utimens;
 
+  public:
+    mutable PolicyCache open_cache;
+
   public:
     const std::string controlfile;
 

src/getattr.cpp

@@ -30,7 +30,6 @@
 
 using std::string;
 using std::vector;
-using mergerfs::Policy;
 
 static
 int

src/getxattr.cpp

@@ -306,6 +306,8 @@ _getxattr_controlfile(const Config &config,
         _getxattr_controlfile_category_policy(config,attr[3],attrvalue);
       else if(attr[2] == "func")
         _getxattr_controlfile_fusefunc_policy(config,attr[3],attrvalue);
+      else if((attr[2] == "cache") && (attr[3] == "open"))
+        _getxattr_controlfile_uint64_t(config.open_cache.timeout,attrvalue);
       break;
     }
 

src/link.cpp

@@ -30,7 +30,6 @@
 
 using std::string;
 using std::vector;
-using mergerfs::Policy;
 using namespace mergerfs;
 
 static

src/listxattr.cpp

@@ -43,24 +43,26 @@ _listxattr_controlfile(char         *list,
   string xattrs;
   const vector<string> strs =
     buildvector<string>
-    ("user.mergerfs.srcmounts")
     ("user.mergerfs.branches")
-    ("user.mergerfs.minfreespace")
-    ("user.mergerfs.moveonenospc")
+    ("user.mergerfs.cache.open")
+    ("user.mergerfs.direct_io")
     ("user.mergerfs.dropcacheonclose")
-    ("user.mergerfs.symlinkify")
-    ("user.mergerfs.symlinkify_timeout")
-    ("user.mergerfs.nullrw")
     ("user.mergerfs.ignorepponrename")
     ("user.mergerfs.link_cow")
+    ("user.mergerfs.minfreespace")
+    ("user.mergerfs.moveonenospc")
+    ("user.mergerfs.nullrw")
+    ("user.mergerfs.pid")
+    ("user.mergerfs.policies")
     ("user.mergerfs.security_capability")
-    ("user.mergerfs.xattr")
+    ("user.mergerfs.srcmounts")
     ("user.mergerfs.statfs")
     ("user.mergerfs.statfs_ignore")
-    ("user.mergerfs.direct_io")
-    ("user.mergerfs.policies")
+    ("user.mergerfs.symlinkify")
+    ("user.mergerfs.symlinkify_timeout")
     ("user.mergerfs.version")
-    ("user.mergerfs.pid");
+    ("user.mergerfs.xattr")
+    ;
 
   xattrs.reserve(1024);
   for(size_t i = 0; i < strs.size(); i++)

src/open.cpp

@@ -20,6 +20,7 @@
 #include "fs_base_open.hpp"
 #include "fs_cow.hpp"
 #include "fs_path.hpp"
+#include "policy_cache.hpp"
 #include "rwlock.hpp"
 #include "ugid.hpp"
 
@@ -28,11 +29,8 @@
 #include <string>
 #include <vector>
 
-#include <fcntl.h>
-
 using std::string;
 using std::vector;
-using mergerfs::Policy;
 
 namespace local
 {
@@ -64,6 +62,7 @@ namespace local
   static
   int
   open(Policy::Func::Search  searchFunc_,
+       PolicyCache          &cache,
        const Branches       &branches_,
        const uint64_t        minfreespace_,
        const char           *fusepath_,
@@ -72,13 +71,13 @@ namespace local
        uint64_t             *fh_)
   {
     int rv;
-    vector<const string*> basepaths;
+    string basepath;
 
-    rv = searchFunc_(branches_,fusepath_,minfreespace_,basepaths);
+    rv = cache(searchFunc_,branches_,fusepath_,minfreespace_,&basepath);
     if(rv == -1)
       return -errno;
 
-    return local::open_core(*basepaths[0],fusepath_,flags_,link_cow_,fh_);
+    return local::open_core(basepath,fusepath_,flags_,link_cow_,fh_);
   }
 }
 
@@ -97,6 +96,7 @@ namespace mergerfs
 
       ffi_->direct_io = config.direct_io;
       return local::open(config.open,
+                         config.open_cache,
                          config.branches,
                          config.minfreespace,
                          fusepath_,

src/option_parser.cpp

@@ -202,6 +202,18 @@ parse_and_process_statfsignore(const std::string          &value_,
   return 0;
 }
 
+static
+int
+parse_and_process_cache(Config &config_,
+                        const string &func_,
+                        const string &value_)
+{
+  if(func_ == "open")
+    return parse_and_process(value_,config_.open_cache.timeout);
+
+  return 1;
+}
+
 static
 int
 parse_and_process_arg(Config            &config,
@@ -233,6 +245,8 @@ parse_and_process_kv_arg(Config            &config,
         rv = config.set_func_policy(keypart[1],value);
       else if(keypart[0] == "category")
         rv = config.set_category_policy(keypart[1],value);
+      else if(keypart[0] == "cache")
+        rv = parse_and_process_cache(config,keypart[1],value);
     }
   else
     {
@@ -336,6 +350,8 @@ usage(void)
     "                           splice_write, splice_move\n"
     "    -o func.<f>=<p>        Set function <f> to policy <p>\n"
     "    -o category.<c>=<p>    Set functions in category <c> to <p>\n"
+    "    -o cache.open=<int>    'open' policy cache timeout in seconds.\n"
+    "                           default = 0 (disabled)\n"
     "    -o direct_io           Bypass page caching, may increase write\n"
     "                           speeds at the cost of reads. Please read docs\n"
     "                           for more details as there are tradeoffs.\n"

src/policy.cpp

@@ -24,65 +24,63 @@
 #define PRESERVES_PATH true
 #define DOESNT_PRESERVE_PATH false
 
-namespace mergerfs
-{
-  const std::vector<Policy> Policy::_policies_ =
-    buildvector<Policy,true>
-    (POLICY(invalid,DOESNT_PRESERVE_PATH))
-    (POLICY(all,DOESNT_PRESERVE_PATH))
-    (POLICY(epall,PRESERVES_PATH))
-    (POLICY(epff,PRESERVES_PATH))
-    (POLICY(eplfs,PRESERVES_PATH))
-    (POLICY(eplus,PRESERVES_PATH))
-    (POLICY(epmfs,PRESERVES_PATH))
-    (POLICY(eprand,PRESERVES_PATH))
-    (POLICY(erofs,DOESNT_PRESERVE_PATH))
-    (POLICY(ff,DOESNT_PRESERVE_PATH))
-    (POLICY(lfs,DOESNT_PRESERVE_PATH))
-    (POLICY(lus,DOESNT_PRESERVE_PATH))
-    (POLICY(mfs,DOESNT_PRESERVE_PATH))
-    (POLICY(newest,DOESNT_PRESERVE_PATH))
-    (POLICY(rand,DOESNT_PRESERVE_PATH));
+const std::vector<Policy> Policy::_policies_ =
+  buildvector<Policy,true>
+  (POLICY(invalid,DOESNT_PRESERVE_PATH))
+  (POLICY(all,DOESNT_PRESERVE_PATH))
+  (POLICY(epall,PRESERVES_PATH))
+  (POLICY(epff,PRESERVES_PATH))
+  (POLICY(eplfs,PRESERVES_PATH))
+  (POLICY(eplus,PRESERVES_PATH))
+  (POLICY(epmfs,PRESERVES_PATH))
+  (POLICY(eprand,PRESERVES_PATH))
+  (POLICY(erofs,DOESNT_PRESERVE_PATH))
+  (POLICY(ff,DOESNT_PRESERVE_PATH))
+  (POLICY(lfs,DOESNT_PRESERVE_PATH))
+  (POLICY(lus,DOESNT_PRESERVE_PATH))
+  (POLICY(mfs,DOESNT_PRESERVE_PATH))
+  (POLICY(newest,DOESNT_PRESERVE_PATH))
+  (POLICY(rand,DOESNT_PRESERVE_PATH));
 
-  const Policy * const Policy::policies = &_policies_[1];
+const Policy * const Policy::policies = &_policies_[1];
 
 #define CONST_POLICY(X) const Policy &Policy::X = Policy::policies[Policy::Enum::X]
 
-  CONST_POLICY(invalid);
-  CONST_POLICY(all);
-  CONST_POLICY(epall);
-  CONST_POLICY(epff);
-  CONST_POLICY(eplfs);
-  CONST_POLICY(eplus);
-  CONST_POLICY(epmfs);
-  CONST_POLICY(eprand);
-  CONST_POLICY(erofs);
-  CONST_POLICY(ff);
-  CONST_POLICY(lfs);
-  CONST_POLICY(lus);
-  CONST_POLICY(mfs);
-  CONST_POLICY(newest);
-  CONST_POLICY(rand);
+CONST_POLICY(invalid);
+CONST_POLICY(all);
+CONST_POLICY(epall);
+CONST_POLICY(epff);
+CONST_POLICY(eplfs);
+CONST_POLICY(eplus);
+CONST_POLICY(epmfs);
+CONST_POLICY(eprand);
+CONST_POLICY(erofs);
+CONST_POLICY(ff);
+CONST_POLICY(lfs);
+CONST_POLICY(lus);
+CONST_POLICY(mfs);
+CONST_POLICY(newest);
+CONST_POLICY(rand);
 
-  const Policy&
-  Policy::find(const std::string &str)
+const Policy&
+Policy::find(const std::string &str)
+{
+for(int i = Enum::BEGIN; i != Enum::END; ++i)
   {
-    for(int i = Enum::BEGIN; i != Enum::END; ++i)
-      {
-        if(policies[i] == str)
-          return policies[i];
-      }
-
-    return invalid;
+    if(policies[i] == str)
+      return policies[i];
   }
 
-  const Policy&
-  Policy::find(const Policy::Enum::Type i)
-  {
-    if(i >= Policy::Enum::BEGIN &&
-       i  < Policy::Enum::END)
-      return policies[i];
+ return invalid;
+}
 
-    return invalid;
-  }
+const Policy&
+Policy::find(const Policy::Enum::Type i)
+{
+  if(i >= Policy::Enum::BEGIN &&
+     i  < Policy::Enum::END)
+    return policies[i];
+
+  return invalid;
 }
+

src/policy.hpp

@@ -24,168 +24,178 @@
 #include <string>
 #include <vector>
 
-namespace mergerfs
+class Policy
 {
-  class Policy
+public:
+  struct Enum
   {
-  public:
-    struct Enum
-    {
-      enum Type
-        {
-          invalid = -1,
-          BEGIN   = 0,
-          all     = BEGIN,
-          epall,
-          epff,
-          eplfs,
-          eplus,
-          epmfs,
-          eprand,
-          erofs,
-          ff,
-          lfs,
-          lus,
-          mfs,
-          newest,
-          rand,
-          END
-        };
-
-      static size_t begin() { return BEGIN; }
-      static size_t end()   { return END; }
-    };
-
-    struct Func
-    {
-      typedef std::string string;
-      typedef std::vector<string> strvec;
-      typedef std::vector<const string*> cstrptrvec;
-      typedef const string cstring;
-      typedef const uint64_t cuint64_t;
-      typedef const strvec cstrvec;
-      typedef const Category::Enum::Type CType;
-
-      typedef int (*Ptr)(CType,const Branches &,const char *,cuint64_t,cstrptrvec &);
-
-      template <CType T>
-      class Base
+    enum Type
       {
-      public:
-        Base(const Policy *p)
-          : func(p->_func)
-        {}
-
-        int
-        operator()(const Branches &b,const char *c,cuint64_t d,cstrptrvec &e)
-        {
-          return func(T,b,c,d,e);
-        }
-
-        int
-        operator()(const Branches &b,const string &c,cuint64_t d,cstrptrvec &e)
-        {
-          return func(T,b,c.c_str(),d,e);
-        }
-
-      private:
-        const Ptr func;
+        invalid = -1,
+        BEGIN   = 0,
+        all     = BEGIN,
+        epall,
+        epff,
+        eplfs,
+        eplus,
+        epmfs,
+        eprand,
+        erofs,
+        ff,
+        lfs,
+        lus,
+        mfs,
+        newest,
+        rand,
+        END
       };
 
-      typedef Base<Category::Enum::action> Action;
-      typedef Base<Category::Enum::create> Create;
-      typedef Base<Category::Enum::search> Search;
-
-      static int invalid(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
-      static int all(CType,const Branches&,const char*,cuint64_t,cstrptrvec&);
-      static int epall(CType,const Branches&,const char*,cuint64_t,cstrptrvec&);
-      static int epff(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
-      static int eplfs(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
-      static int eplus(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
-      static int epmfs(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
-      static int eprand(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
-      static int erofs(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
-      static int ff(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
-      static int lfs(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
-      static int lus(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
-      static int mfs(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
-      static int newest(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
-      static int rand(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
-    };
+    static size_t begin() { return BEGIN; }
+    static size_t end()   { return END; }
+  };
 
-  private:
-    Enum::Type  _enum;
-    std::string _str;
-    Func::Ptr   _func;
-    bool        _path_preserving;
-
-  public:
-    Policy()
-      : _enum(invalid),
-        _str(invalid),
-        _func(invalid),
-        _path_preserving(false)
-    {
-    }
-
-    Policy(const Enum::Type   enum_,
-           const std::string &str_,
-           const Func::Ptr    func_,
-           const bool         path_preserving_)
-      : _enum(enum_),
-        _str(str_),
-        _func(func_),
-        _path_preserving(path_preserving_)
+  struct Func
+  {
+    typedef std::string string;
+    typedef std::vector<string> strvec;
+    typedef std::vector<const string*> cstrptrvec;
+    typedef const string cstring;
+    typedef const uint64_t cuint64_t;
+    typedef const strvec cstrvec;
+    typedef const Category::Enum::Type CType;
+
+    typedef int (*Ptr)(CType,const Branches &,const char *,cuint64_t,cstrptrvec &);
+
+    template <CType T>
+    class Base
     {
-    }
+    public:
+      Base(const Policy *p)
+        : func(p->_func)
+      {}
 
-    bool
-    path_preserving() const
-    {
-      return _path_preserving;
-    }
-
-  public:
-    operator const Enum::Type() const { return _enum; }
-    operator const std::string&() const { return _str; }
-    operator const Func::Ptr() const { return _func; }
-    operator const Policy*() const { return this; }
-
-    bool operator==(const Enum::Type enum_) const
-    { return _enum == enum_; }
-    bool operator==(const std::string &str_) const
-    { return _str == str_; }
-    bool operator==(const Func::Ptr func_) const
-    { return _func == func_; }
-
-    bool operator!=(const Policy &r) const
-    { return _enum != r._enum; }
-
-    bool operator<(const Policy &r) const
-    { return _enum < r._enum; }
-
-  public:
-    static const Policy &find(const std::string&);
-    static const Policy &find(const Enum::Type);
-
-  public:
-    static const std::vector<Policy> _policies_;
-    static const Policy * const      policies;
-
-    static const Policy &invalid;
-    static const Policy &all;
-    static const Policy &epall;
-    static const Policy &epff;
-    static const Policy &eplfs;
-    static const Policy &eplus;
-    static const Policy &epmfs;
-    static const Policy &eprand;
-    static const Policy &erofs;
-    static const Policy &ff;
-    static const Policy &lfs;
-    static const Policy &lus;
-    static const Policy &mfs;
-    static const Policy &newest;
-    static const Policy &rand;
+      int
+      operator()(const Branches &b,const char *c,cuint64_t d,cstrptrvec &e)
+      {
+        return func(T,b,c,d,e);
+      }
+
+      int
+      operator()(const Branches &b,const string &c,cuint64_t d,cstrptrvec &e)
+      {
+        return func(T,b,c.c_str(),d,e);
+      }
+
+      int
+      operator()(const Branches &b,const char *c,cuint64_t d,string *e)
+      {
+        int rv;
+        cstrptrvec v;
+
+        rv = func(T,b,c,d,v);
+        if(!v.empty())
+          *e = *v[0];
+
+        return rv;
+      }
+
+    private:
+      const Ptr func;
+    };
+
+    typedef Base<Category::Enum::action> Action;
+    typedef Base<Category::Enum::create> Create;
+    typedef Base<Category::Enum::search> Search;
+
+    static int invalid(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
+    static int all(CType,const Branches&,const char*,cuint64_t,cstrptrvec&);
+    static int epall(CType,const Branches&,const char*,cuint64_t,cstrptrvec&);
+    static int epff(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
+    static int eplfs(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
+    static int eplus(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
+    static int epmfs(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
+    static int eprand(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
+    static int erofs(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
+    static int ff(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
+    static int lfs(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
+    static int lus(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
+    static int mfs(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
+    static int newest(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
+    static int rand(CType,const Branches&,const char *,cuint64_t,cstrptrvec&);
   };
-}
+
+private:
+  Enum::Type  _enum;
+  std::string _str;
+  Func::Ptr   _func;
+  bool        _path_preserving;
+
+public:
+  Policy()
+    : _enum(invalid),
+      _str(invalid),
+      _func(invalid),
+      _path_preserving(false)
+  {
+  }
+
+  Policy(const Enum::Type   enum_,
+         const std::string &str_,
+         const Func::Ptr    func_,
+         const bool         path_preserving_)
+    : _enum(enum_),
+      _str(str_),
+      _func(func_),
+      _path_preserving(path_preserving_)
+  {
+  }
+
+  bool
+  path_preserving() const
+  {
+    return _path_preserving;
+  }
+
+public:
+  operator const Enum::Type() const { return _enum; }
+  operator const std::string&() const { return _str; }
+  operator const Func::Ptr() const { return _func; }
+  operator const Policy*() const { return this; }
+
+  bool operator==(const Enum::Type enum_) const
+  { return _enum == enum_; }
+  bool operator==(const std::string &str_) const
+  { return _str == str_; }
+  bool operator==(const Func::Ptr func_) const
+  { return _func == func_; }
+
+  bool operator!=(const Policy &r) const
+  { return _enum != r._enum; }
+
+  bool operator<(const Policy &r) const
+  { return _enum < r._enum; }
+
+public:
+  static const Policy &find(const std::string&);
+  static const Policy &find(const Enum::Type);
+
+public:
+  static const std::vector<Policy> _policies_;
+  static const Policy * const      policies;
+
+  static const Policy &invalid;
+  static const Policy &all;
+  static const Policy &epall;
+  static const Policy &epff;
+  static const Policy &eplfs;
+  static const Policy &eplus;
+  static const Policy &epmfs;
+  static const Policy &eprand;
+  static const Policy &erofs;
+  static const Policy &ff;
+  static const Policy &lfs;
+  static const Policy &lus;
+  static const Policy &mfs;
+  static const Policy &newest;
+  static const Policy &rand;
+};

src/policy_all.cpp

@@ -65,18 +65,15 @@ namespace all
   }
 }
 
-namespace mergerfs
+int
+Policy::Func::all(const Category::Enum::Type  type,
+                  const Branches             &branches_,
+                  const char                 *fusepath,
+                  const uint64_t              minfreespace,
+                  vector<const string*>      &paths)
 {
-  int
-  Policy::Func::all(const Category::Enum::Type  type,
-                    const Branches             &branches_,
-                    const char                 *fusepath,
-                    const uint64_t              minfreespace,
-                    vector<const string*>      &paths)
-  {
-    if(type == Category::Enum::create)
-      return all::create(branches_,minfreespace,paths);
+  if(type == Category::Enum::create)
+    return all::create(branches_,minfreespace,paths);
 
-    return Policy::Func::epall(type,branches_,fusepath,minfreespace,paths);
-  }
+  return Policy::Func::epall(type,branches_,fusepath,minfreespace,paths);
 }

src/policy_cache.cpp

@@ -0,0 +1,128 @@
+#include "policy_cache.hpp"
+
+#include <cstdlib>
+#include <map>
+#include <string>
+#include <vector>
+
+#include <sys/time.h>
+
+using std::map;
+using std::string;
+using std::vector;
+
+static const uint64_t DEFAULT_TIMEOUT = 0;
+
+namespace local
+{
+  static
+  uint64_t
+  get_time(void)
+  {
+    uint64_t rv;
+    struct timeval now;
+
+    ::gettimeofday(&now,NULL);
+
+    rv = now.tv_sec;
+
+    return rv;
+  }
+}
+
+
+PolicyCache::Value::Value()
+  : time(0),
+    path()
+{
+
+}
+
+PolicyCache::PolicyCache(void)
+  : timeout(DEFAULT_TIMEOUT)
+{
+}
+
+void
+PolicyCache::erase(const char *fusepath_)
+{
+  pthread_mutex_lock(&_lock);
+
+  _cache.erase(fusepath_);
+
+  pthread_mutex_unlock(&_lock);
+}
+
+void
+PolicyCache::cleanup(const int prob_)
+{
+  uint64_t now;
+  map<string,Value>::iterator i;
+
+  if(rand() % prob_)
+    return;
+
+  now = local::get_time();
+
+  pthread_mutex_lock(&_lock);
+
+  i = _cache.begin();
+  while(i != _cache.end())
+    {
+      if((now - i->second.time) >= timeout)
+        _cache.erase(i++);
+      else
+        ++i;
+    }
+
+  pthread_mutex_unlock(&_lock);
+}
+
+void
+PolicyCache::clear(void)
+{
+  pthread_mutex_lock(&_lock);
+
+  _cache.clear();
+
+  pthread_mutex_unlock(&_lock);
+}
+
+int
+PolicyCache::operator()(Policy::Func::Search &func_,
+                        const Branches       &branches_,
+                        const char           *fusepath_,
+                        const uint64_t        minfreespace_,
+                        std::string          *branch_)
+{
+  int rv;
+  Value *v;
+  uint64_t now;
+  string branch;
+
+  if(timeout == 0)
+    return func_(branches_,fusepath_,minfreespace_,branch_);
+
+  now = local::get_time();
+
+  pthread_mutex_lock(&_lock);
+  v = &_cache[fusepath_];
+
+  if((now - v->time) >= timeout)
+    {
+      pthread_mutex_unlock(&_lock);
+      rv = func_(branches_,fusepath_,minfreespace_,&branch);
+      if(rv == -1)
+        return -1;
+
+      pthread_mutex_lock(&_lock);
+      v->time = now;
+      v->path = branch;
+    }
+
+  *branch_ = v->path;
+
+  pthread_mutex_unlock(&_lock);
+
+  return 0;
+}

src/policy_cache.hpp

@@ -0,0 +1,61 @@
+/*
+  ISC License
+
+  Copyright (c) 2019, Antonio SJ Musumeci <trapexit@spawn.link>
+
+  Permission to use, copy, modify, and/or distribute this software for any
+  purpose with or without fee is hereby granted, provided that the above
+  copyright notice and this permission notice appear in all copies.
+
+  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#pragma once
+
+#include "policy.hpp"
+
+#include <string>
+#include <map>
+
+#include <pthread.h>
+#include <stdint.h>
+
+class PolicyCache
+{
+public:
+  struct Value
+  {
+    Value();
+
+    uint64_t    time;
+    std::string path;
+  };
+
+public:
+  PolicyCache(void);
+
+public:
+  void erase(const char *fusepath_);
+  void cleanup(const int prob_ = 1);
+  void clear(void);
+
+public:
+  int operator()(Policy::Func::Search &func_,
+                 const Branches       &branches_,
+                 const char           *fusepath_,
+                 const uint64_t        minfreespace_,
+                 std::string          *branch_);
+
+public:
+  uint64_t timeout;
+
+private:
+  pthread_mutex_t             _lock;
+  std::map<std::string,Value> _cache;
+};

src/policy_epall.cpp

@@ -128,24 +128,21 @@ namespace epall
   }
 }
 
-namespace mergerfs
+int
+Policy::Func::epall(const Category::Enum::Type  type,
+                    const Branches             &branches_,
+                    const char                 *fusepath,
+                    const uint64_t              minfreespace,
+                    vector<const string*>      &paths)
 {
-  int
-  Policy::Func::epall(const Category::Enum::Type  type,
-                      const Branches             &branches_,
-                      const char                 *fusepath,
-                      const uint64_t              minfreespace,
-                      vector<const string*>      &paths)
-  {
-    switch(type)
-      {
-      case Category::Enum::create:
-        return epall::create(branches_,fusepath,minfreespace,paths);
-      case Category::Enum::action:
-        return epall::action(branches_,fusepath,paths);
-      case Category::Enum::search:
-      default:
-        return epall::search(branches_,fusepath,paths);
-      }
-  }
+  switch(type)
+    {
+    case Category::Enum::create:
+      return epall::create(branches_,fusepath,minfreespace,paths);
+    case Category::Enum::action:
+      return epall::action(branches_,fusepath,paths);
+    case Category::Enum::search:
+    default:
+      return epall::search(branches_,fusepath,paths);
+    }
 }

src/policy_epff.cpp

@@ -27,7 +27,6 @@
 
 using std::string;
 using std::vector;
-using mergerfs::Category;
 
 namespace epff
 {
@@ -126,24 +125,21 @@ namespace epff
   }
 }
 
-namespace mergerfs
+int
+Policy::Func::epff(const Category::Enum::Type  type,
+                   const Branches             &branches_,
+                   const char                 *fusepath,
+                   const uint64_t              minfreespace,
+                   vector<const string*>      &paths)
 {
-  int
-  Policy::Func::epff(const Category::Enum::Type  type,
-                     const Branches             &branches_,
-                     const char                 *fusepath,
-                     const uint64_t              minfreespace,
-                     vector<const string*>      &paths)
-  {
-    switch(type)
-      {
-      case Category::Enum::create:
-        return epff::create(branches_,fusepath,minfreespace,paths);
-      case Category::Enum::action:
-        return epff::action(branches_,fusepath,paths);
-      case Category::Enum::search:
-      default:
-        return epff::search(branches_,fusepath,paths);
-      }
-  }
+  switch(type)
+    {
+    case Category::Enum::create:
+      return epff::create(branches_,fusepath,minfreespace,paths);
+    case Category::Enum::action:
+      return epff::action(branches_,fusepath,paths);
+    case Category::Enum::search:
+    default:
+      return epff::search(branches_,fusepath,paths);
+    }
 }

src/policy_eplfs.cpp

@@ -28,7 +28,6 @@
 
 using std::string;
 using std::vector;
-using mergerfs::Category;
 
 namespace eplfs
 {
@@ -162,24 +161,21 @@ namespace eplfs
   }
 }
 
-namespace mergerfs
+int
+Policy::Func::eplfs(const Category::Enum::Type  type,
+                    const Branches             &branches_,
+                    const char                 *fusepath,
+                    const uint64_t              minfreespace,
+                    vector<const string*>      &paths)
 {
-  int
-  Policy::Func::eplfs(const Category::Enum::Type  type,
-                      const Branches             &branches_,
-                      const char                 *fusepath,
-                      const uint64_t              minfreespace,
-                      vector<const string*>      &paths)
-  {
-    switch(type)
-      {
-      case Category::Enum::create:
-        return eplfs::create(branches_,fusepath,minfreespace,paths);
-      case Category::Enum::action:
-        return eplfs::action(branches_,fusepath,paths);
-      case Category::Enum::search:
-      default:
-        return eplfs::search(branches_,fusepath,paths);
-      }
-  }
+  switch(type)
+    {
+    case Category::Enum::create:
+      return eplfs::create(branches_,fusepath,minfreespace,paths);
+    case Category::Enum::action:
+      return eplfs::action(branches_,fusepath,paths);
+    case Category::Enum::search:
+    default:
+      return eplfs::search(branches_,fusepath,paths);
+    }
 }

src/policy_eplus.cpp

@@ -28,7 +28,6 @@
 
 using std::string;
 using std::vector;
-using mergerfs::Category;
 
 namespace eplus
 {
@@ -162,24 +161,21 @@ namespace eplus
   }
 }
 
-namespace mergerfs
+int
+Policy::Func::eplus(const Category::Enum::Type  type,
+                    const Branches             &branches_,
+                    const char                 *fusepath,
+                    const uint64_t              minfreespace,
+                    vector<const string*>      &paths)
 {
-  int
-  Policy::Func::eplus(const Category::Enum::Type  type,
-                      const Branches             &branches_,
-                      const char                 *fusepath,
-                      const uint64_t              minfreespace,
-                      vector<const string*>      &paths)
-  {
-    switch(type)
-      {
-      case Category::Enum::create:
-        return eplus::create(branches_,fusepath,minfreespace,paths);
-      case Category::Enum::action:
-        return eplus::action(branches_,fusepath,paths);
-      case Category::Enum::search:
-      default:
-        return eplus::search(branches_,fusepath,paths);
-      }
-  }
+  switch(type)
+    {
+    case Category::Enum::create:
+      return eplus::create(branches_,fusepath,minfreespace,paths);
+    case Category::Enum::action:
+      return eplus::action(branches_,fusepath,paths);
+    case Category::Enum::search:
+    default:
+      return eplus::search(branches_,fusepath,paths);
+    }
 }

src/policy_epmfs.cpp

@@ -28,7 +28,6 @@
 
 using std::string;
 using std::vector;
-using mergerfs::Category;
 
 namespace epmfs
 {
@@ -162,24 +161,21 @@ namespace epmfs
   }
 }
 
-namespace mergerfs
+int
+Policy::Func::epmfs(const Category::Enum::Type  type,
+                    const Branches             &branches_,
+                    const char                 *fusepath,
+                    const uint64_t              minfreespace,
+                    vector<const string*>      &paths)
 {
-  int
-  Policy::Func::epmfs(const Category::Enum::Type  type,
-                      const Branches             &branches_,
-                      const char                 *fusepath,
-                      const uint64_t              minfreespace,
-                      vector<const string*>      &paths)
-  {
-    switch(type)
-      {
-      case Category::Enum::create:
-        return epmfs::create(branches_,fusepath,minfreespace,paths);
-      case Category::Enum::action:
-        return epmfs::action(branches_,fusepath,paths);
-      case Category::Enum::search:
-      default:
-        return epmfs::search(branches_,fusepath,paths);
-      }
-  }
+  switch(type)
+    {
+    case Category::Enum::create:
+      return epmfs::create(branches_,fusepath,minfreespace,paths);
+    case Category::Enum::action:
+      return epmfs::action(branches_,fusepath,paths);
+    case Category::Enum::search:
+    default:
+      return epmfs::search(branches_,fusepath,paths);
+    }
 }

src/policy_eprand.cpp

@@ -24,21 +24,18 @@
 using std::string;
 using std::vector;
 
-namespace mergerfs
+int
+Policy::Func::eprand(const Category::Enum::Type  type,
+                     const Branches             &branches_,
+                     const char                 *fusepath,
+                     const uint64_t              minfreespace,
+                     vector<const string*>      &paths)
 {
-  int
-  Policy::Func::eprand(const Category::Enum::Type  type,
-                       const Branches             &branches_,
-                       const char                 *fusepath,
-                       const uint64_t              minfreespace,
-                       vector<const string*>      &paths)
-  {
-    int rv;
-
-    rv = Policy::Func::epall(type,branches_,fusepath,minfreespace,paths);
-    if(rv == 0)
-      std::random_shuffle(paths.begin(),paths.end());
-
-    return rv;
-  }
+  int rv;
+
+  rv = Policy::Func::epall(type,branches_,fusepath,minfreespace,paths);
+  if(rv == 0)
+    std::random_shuffle(paths.begin(),paths.end());
+
+  return rv;
 }

src/policy_erofs.cpp

@@ -23,15 +23,12 @@
 using std::string;
 using std::vector;
 
-namespace mergerfs
+int
+Policy::Func::erofs(const Category::Enum::Type  type,
+                    const Branches             &branches_,
+                    const char                 *fusepath,
+                    const uint64_t              minfreespace,
+                    vector<const string*>      &paths)
 {
-  int
-  Policy::Func::erofs(const Category::Enum::Type  type,
-                      const Branches             &branches_,
-                      const char                 *fusepath,
-                      const uint64_t              minfreespace,
-                      vector<const string*>      &paths)
-  {
-    return (errno=EROFS,-1);
-  }
+  return (errno=EROFS,-1);
 }

src/policy_ff.cpp

@@ -65,18 +65,15 @@ namespace ff
   }
 }
 
-namespace mergerfs
+int
+Policy::Func::ff(const Category::Enum::Type  type,
+                 const Branches             &branches_,
+                 const char                 *fusepath,
+                 const uint64_t              minfreespace,
+                 vector<const string*>      &paths)
 {
-  int
-  Policy::Func::ff(const Category::Enum::Type  type,
-                   const Branches             &branches_,
-                   const char                 *fusepath,
-                   const uint64_t              minfreespace,
-                   vector<const string*>      &paths)
-  {
-    if(type == Category::Enum::create)
-      return ff::create(branches_,minfreespace,paths);
+  if(type == Category::Enum::create)
+    return ff::create(branches_,minfreespace,paths);
 
-    return Policy::Func::epff(type,branches_,fusepath,minfreespace,paths);
-  }
+  return Policy::Func::epff(type,branches_,fusepath,minfreespace,paths);
 }

src/policy_invalid.cpp

@@ -23,15 +23,12 @@
 using std::string;
 using std::vector;
 
-namespace mergerfs
+int
+Policy::Func::invalid(const Category::Enum::Type  type,
+                      const Branches             &branches_,
+                      const char                 *fusepath,
+                      const uint64_t              minfreespace,
+                      vector<const string*>      &paths)
 {
-  int
-  Policy::Func::invalid(const Category::Enum::Type  type,
-                        const Branches             &branches_,
-                        const char                 *fusepath,
-                        const uint64_t              minfreespace,
-                        vector<const string*>      &paths)
-  {
-    return (errno=EINVAL,-1);
-  }
+  return (errno=EINVAL,-1);
 }

src/policy_lfs.cpp

@@ -28,7 +28,6 @@
 
 using std::string;
 using std::vector;
-using mergerfs::Category;
 
 namespace lfs
 {
@@ -77,18 +76,15 @@ namespace lfs
   }
 }
 
-namespace mergerfs
+int
+Policy::Func::lfs(const Category::Enum::Type  type,
+                  const Branches             &branches_,
+                  const char                 *fusepath,
+                  const uint64_t              minfreespace,
+                  vector<const string*>      &paths)
 {
-  int
-  Policy::Func::lfs(const Category::Enum::Type  type,
-                    const Branches             &branches_,
-                    const char                 *fusepath,
-                    const uint64_t              minfreespace,
-                    vector<const string*>      &paths)
-  {
-    if(type == Category::Enum::create)
-      return lfs::create(branches_,minfreespace,paths);
+  if(type == Category::Enum::create)
+    return lfs::create(branches_,minfreespace,paths);
 
-    return Policy::Func::eplfs(type,branches_,fusepath,minfreespace,paths);
-  }
+  return Policy::Func::eplfs(type,branches_,fusepath,minfreespace,paths);
 }

src/policy_lus.cpp

@@ -28,7 +28,6 @@
 
 using std::string;
 using std::vector;
-using mergerfs::Category;
 
 namespace lus
 {
@@ -77,18 +76,15 @@ namespace lus
   }
 }
 
-namespace mergerfs
+int
+Policy::Func::lus(const Category::Enum::Type  type,
+                  const Branches             &branches_,
+                  const char                 *fusepath,
+                  const uint64_t              minfreespace,
+                  vector<const string*>      &paths)
 {
-  int
-  Policy::Func::lus(const Category::Enum::Type  type,
-                    const Branches             &branches_,
-                    const char                 *fusepath,
-                    const uint64_t              minfreespace,
-                    vector<const string*>      &paths)
-  {
-    if(type == Category::Enum::create)
-      return lus::create(branches_,minfreespace,paths);
+  if(type == Category::Enum::create)
+    return lus::create(branches_,minfreespace,paths);
 
-    return Policy::Func::eplus(type,branches_,fusepath,minfreespace,paths);
-  }
+  return Policy::Func::eplus(type,branches_,fusepath,minfreespace,paths);
 }

src/policy_mfs.cpp

@@ -27,7 +27,6 @@
 
 using std::string;
 using std::vector;
-using mergerfs::Category;
 
 namespace mfs
 {
@@ -76,18 +75,15 @@ namespace mfs
   }
 }
 
-namespace mergerfs
+int
+Policy::Func::mfs(const Category::Enum::Type  type,
+                  const Branches             &branches_,
+                  const char                 *fusepath,
+                  const uint64_t              minfreespace,
+                  vector<const string*>      &paths)
 {
-  int
-  Policy::Func::mfs(const Category::Enum::Type  type,
-                    const Branches             &branches_,
-                    const char                 *fusepath,
-                    const uint64_t              minfreespace,
-                    vector<const string*>      &paths)
-  {
-    if(type == Category::Enum::create)
-      return mfs::create(branches_,minfreespace,paths);
+  if(type == Category::Enum::create)
+    return mfs::create(branches_,minfreespace,paths);
 
-    return Policy::Func::epmfs(type,branches_,fusepath,minfreespace,paths);
-  }
+  return Policy::Func::epmfs(type,branches_,fusepath,minfreespace,paths);
 }

src/policy_newest.cpp

@@ -161,24 +161,21 @@ namespace newest
   }
 }
 
-namespace mergerfs
+int
+Policy::Func::newest(const Category::Enum::Type  type,
+                     const Branches             &branches_,
+                     const char                 *fusepath,
+                     const uint64_t              minfreespace,
+                     vector<const string*>      &paths)
 {
-  int
-  Policy::Func::newest(const Category::Enum::Type  type,
-                       const Branches             &branches_,
-                       const char                 *fusepath,
-                       const uint64_t              minfreespace,
-                       vector<const string*>      &paths)
-  {
-    switch(type)
-      {
-      case Category::Enum::create:
-        return newest::create(branches_,fusepath,minfreespace,paths);
-      case Category::Enum::action:
-        return newest::action(branches_,fusepath,paths);
-      case Category::Enum::search:
-      default:
-        return newest::search(branches_,fusepath,paths);
-      }
-  }
+  switch(type)
+    {
+    case Category::Enum::create:
+      return newest::create(branches_,fusepath,minfreespace,paths);
+    case Category::Enum::action:
+      return newest::action(branches_,fusepath,paths);
+    case Category::Enum::search:
+    default:
+      return newest::search(branches_,fusepath,paths);
+    }
 }

src/policy_rand.cpp

@@ -24,21 +24,18 @@
 using std::string;
 using std::vector;
 
-namespace mergerfs
+int
+Policy::Func::rand(const Category::Enum::Type  type,
+                   const Branches             &branches_,
+                   const char                 *fusepath,
+                   const uint64_t              minfreespace,
+                   vector<const string*>      &paths)
 {
-  int
-  Policy::Func::rand(const Category::Enum::Type  type,
-                     const Branches             &branches_,
-                     const char                 *fusepath,
-                     const uint64_t              minfreespace,
-                     vector<const string*>      &paths)
-  {
-    int rv;
-
-    rv = Policy::Func::all(type,branches_,fusepath,minfreespace,paths);
-    if(rv == 0)
-      std::random_shuffle(paths.begin(),paths.end());
-
-    return rv;
-  }
+  int rv;
+
+  rv = Policy::Func::all(type,branches_,fusepath,minfreespace,paths);
+  if(rv == 0)
+    std::random_shuffle(paths.begin(),paths.end());
+
+  return rv;
 }

src/readlink.cpp

@@ -29,7 +29,6 @@
 
 using std::string;
 using std::vector;
-using mergerfs::Policy;
 
 static
 int

src/release.cpp

@@ -14,34 +14,37 @@
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
-#include <fuse.h>
-
-#include <string>
-
 #include "config.hpp"
 #include "errno.hpp"
 #include "fileinfo.hpp"
 #include "fs_base_close.hpp"
 #include "fs_base_fadvise.hpp"
 
-static
-int
-_release(FileInfo   *fi,
-         const bool  dropcacheonclose)
+#include <fuse.h>
+
+#include <string>
+
+namespace local
 {
-  // according to Feh of nocache calling it once doesn't always work
-  // https://github.com/Feh/nocache
-  if(dropcacheonclose)
-    {
-      fs::fadvise_dontneed(fi->fd);
-      fs::fadvise_dontneed(fi->fd);
-    }
+  static
+  int
+  release(FileInfo   *fi_,
+          const bool  dropcacheonclose_)
+  {
+    // according to Feh of nocache calling it once doesn't always work
+    // https://github.com/Feh/nocache
+    if(dropcacheonclose_)
+      {
+        fs::fadvise_dontneed(fi_->fd);
+        fs::fadvise_dontneed(fi_->fd);
+      }
 
-  fs::close(fi->fd);
+    fs::close(fi_->fd);
 
-  delete fi;
+    delete fi_;
 
-  return 0;
+    return 0;
+  }
 }
 
 namespace mergerfs
@@ -49,13 +52,15 @@ namespace mergerfs
   namespace fuse
   {
     int
-    release(const char     *fusepath,
-            fuse_file_info *ffi)
+    release(const char     *fusepath_,
+            fuse_file_info *ffi_)
     {
       const Config &config = Config::get();
-      FileInfo     *fi     = reinterpret_cast<FileInfo*>(ffi->fh);
+      FileInfo     *fi     = reinterpret_cast<FileInfo*>(ffi_->fh);
+
+      config.open_cache.cleanup(10);
 
-      return _release(fi,config.dropcacheonclose);
+      return local::release(fi,config.dropcacheonclose);
     }
   }
 }

src/releasedir.cpp

@@ -14,17 +14,21 @@
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
-#include <fuse.h>
-
+#include "config.hpp"
 #include "dirinfo.hpp"
 
-static
-int
-_releasedir(DirInfo *di)
+#include <fuse.h>
+
+namespace local
 {
-  delete di;
+  static
+  int
+  releasedir(DirInfo *di_)
+  {
+    delete di_;
 
-  return 0;
+    return 0;
+  }
 }
 
 namespace mergerfs
@@ -32,12 +36,15 @@ namespace mergerfs
   namespace fuse
   {
     int
-    releasedir(const char     *fusepath,
-               fuse_file_info *ffi)
+    releasedir(const char     *fusepath_,
+               fuse_file_info *ffi_)
     {
-      DirInfo *di = reinterpret_cast<DirInfo*>(ffi->fh);
+      const Config &config = Config::get();
+      DirInfo      *di     = reinterpret_cast<DirInfo*>(ffi_->fh);
+
+      config.open_cache.cleanup(10);
 
-      return ::_releasedir(di);
+      return local::releasedir(di);
     }
   }
 }

src/removexattr.cpp

@@ -29,7 +29,6 @@
 
 using std::string;
 using std::vector;
-using mergerfs::Policy;
 
 static
 int

src/rename.cpp

@@ -283,6 +283,8 @@ namespace mergerfs
       const ugid::Set          ugid(fc->uid,fc->gid);
       const rwlock::ReadGuard  readlock(&config.branches_lock);
 
+      config.open_cache.erase(oldpath);
+
       if(config.create->path_preserving() && !config.ignorepponrename)
         return _rename_preserve_path(config.getattr,
                                      config.rename,

src/rmdir.cpp

@@ -30,7 +30,6 @@
 
 using std::string;
 using std::vector;
-using mergerfs::Policy;
 
 static
 int

src/setxattr.cpp

@@ -37,7 +37,6 @@ static const char SECURITY_CAPABILITY[] = "security.capability";
 
 using std::string;
 using std::vector;
-using mergerfs::Policy;
 using mergerfs::FuseFunc;
 using namespace mergerfs;
 
@@ -229,6 +228,9 @@ _setxattr_controlfile_func_policy(Config       &config,
   if((flags & XATTR_CREATE) == XATTR_CREATE)
     return -EEXIST;
 
+  if(funcname == "open")
+    config.open_cache.clear();
+
   rv = config.set_func_policy(funcname,attrval);
   if(rv == -1)
     return -errno;
@@ -248,6 +250,9 @@ _setxattr_controlfile_category_policy(Config       &config,
   if((flags & XATTR_CREATE) == XATTR_CREATE)
     return -EEXIST;
 
+  if(categoryname == "search")
+    config.open_cache.clear();
+
   rv = config.set_category_policy(categoryname,attrval);
   if(rv == -1)
     return -errno;
@@ -340,6 +345,10 @@ _setxattr_controlfile(Config       &config,
                                                  attr[3],
                                                  attrval,
                                                  flags);
+      else if((attr[2] == "cache") && (attr[3] == "open"))
+        return _setxattr_uint64_t(attrval,
+                                  flags,
+                                  config.open_cache.timeout);
       break;
 
     default:

src/truncate.cpp

@@ -32,7 +32,6 @@
 
 using std::string;
 using std::vector;
-using mergerfs::Policy;
 
 static
 int

src/unlink.cpp

@@ -1,5 +1,5 @@
 /*
-  Copyright (c) 2016, Antonio SJ Musumeci <trapexit@spawn.link>
+  Copyright (c) 2019, Antonio SJ Musumeci <trapexit@spawn.link>
 
   Permission to use, copy, modify, and/or distribute this software for any
   purpose with or without fee is hereby granted, provided that the above
@@ -14,13 +14,6 @@
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
-#include <fuse.h>
-
-#include <unistd.h>
-
-#include <string>
-#include <vector>
-
 #include "config.hpp"
 #include "errno.hpp"
 #include "fs_base_unlink.hpp"
@@ -29,57 +22,66 @@
 #include "rwlock.hpp"
 #include "ugid.hpp"
 
+#include <fuse.h>
+
+#include <string>
+#include <vector>
+
+#include <unistd.h>
+
 using std::string;
 using std::vector;
-using mergerfs::Policy;
 
-static
-int
-_unlink_loop_core(const string *basepath,
-                  const char   *fusepath,
-                  const int     error)
+namespace local
 {
-  int rv;
-  string fullpath;
+  static
+  int
+  unlink_loop_core(const string *basepath_,
+                   const char   *fusepath_,
+                   const int     error_)
+  {
+    int rv;
+    string fullpath;
 
-  fs::path::make(basepath,fusepath,fullpath);
+    fs::path::make(basepath_,fusepath_,fullpath);
 
-  rv = fs::unlink(fullpath);
+    rv = fs::unlink(fullpath);
 
-  return error::calc(rv,error,errno);
-}
+    return error::calc(rv,error_,errno);
+  }
 
-static
-int
-_unlink_loop(const vector<const string*> &basepaths,
-             const char *fusepath)
-{
-  int error;
+  static
+  int
+  unlink_loop(const vector<const string*> &basepaths_,
+              const char                  *fusepath_)
+  {
+    int error;
 
-  error = -1;
-  for(size_t i = 0, ei = basepaths.size(); i != ei; i++)
-    {
-      error = _unlink_loop_core(basepaths[i],fusepath,error);
-    }
+    error = -1;
+    for(size_t i = 0, ei = basepaths_.size(); i != ei; i++)
+      {
+        error = local::unlink_loop_core(basepaths_[i],fusepath_,error);
+      }
 
-  return -error;
-}
+    return -error;
+  }
 
-static
-int
-_unlink(Policy::Func::Action  actionFunc,
-        const Branches       &branches_,
-        const uint64_t        minfreespace,
-        const char           *fusepath)
-{
-  int rv;
-  vector<const string*> basepaths;
+  static
+  int
+  unlink(Policy::Func::Action  actionFunc_,
+         const Branches       &branches_,
+         const uint64_t        minfreespace_,
+         const char           *fusepath_)
+  {
+    int rv;
+    vector<const string*> basepaths;
 
-  rv = actionFunc(branches_,fusepath,minfreespace,basepaths);
-  if(rv == -1)
-    return -errno;
+    rv = actionFunc_(branches_,fusepath_,minfreespace_,basepaths);
+    if(rv == -1)
+      return -errno;
 
-  return _unlink_loop(basepaths,fusepath);
+    return local::unlink_loop(basepaths,fusepath_);
+  }
 }
 
 namespace mergerfs
@@ -87,17 +89,19 @@ namespace mergerfs
   namespace fuse
   {
     int
-    unlink(const char *fusepath)
+    unlink(const char *fusepath_)
     {
       const fuse_context      *fc     = fuse_get_context();
       const Config            &config = Config::get(fc);
       const ugid::Set          ugid(fc->uid,fc->gid);
       const rwlock::ReadGuard  readlock(&config.branches_lock);
 
-      return _unlink(config.unlink,
-                     config.branches,
-                     config.minfreespace,
-                     fusepath);
+      config.open_cache.erase(fusepath_);
+
+      return local::unlink(config.unlink,
+                           config.branches,
+                           config.minfreespace,
+                           fusepath_);
     }
   }
 }

src/utimens.cpp

@@ -31,7 +31,6 @@
 
 using std::string;
 using std::vector;
-using mergerfs::Policy;
 
 static
 int