add existing path, least free space policy. closes #216

src/link.cpp

@@ -246,16 +246,16 @@ namespace mergerfs
       const ugid::Set          ugid(fc->uid,fc->gid);
       const rwlock::ReadGuard  readlock(&config.srcmountslock);
 
-      if(config.create != Policy::epmfs)
-        return _link_create_path(config.link,
+      if(config.create->path_preserving())
+        return _link_preserve_path(config.getattr,
+                                   config.link,
                                    config.create,
                                    config.srcmounts,
                                    config.minfreespace,
                                    from,
                                    to);
 
-      return _link_preserve_path(config.getattr,
-                                 config.link,
+      return _link_create_path(config.link,
                                config.create,
                                config.srcmounts,
                                config.minfreespace,

src/policy.cpp

@@ -20,27 +20,30 @@
 #include "fs.hpp"
 #include "buildvector.hpp"
 
-#define POLICY(X) (Policy(Policy::Enum::X,#X,Policy::Func::X))
+#define POLICY(X,PP) (Policy(Policy::Enum::X,#X,Policy::Func::X,PP))
+#define PRESERVES_PATH true
+#define DOESNT_PRESERVE_PATH false
 
 namespace mergerfs
 {
   const std::vector<Policy> Policy::_policies_ =
     buildvector<Policy,true>
-    (POLICY(invalid))
-    (POLICY(all))
-    (POLICY(einval))
-    (POLICY(enosys))
-    (POLICY(enotsup))
-    (POLICY(epmfs))
-    (POLICY(erofs))
-    (POLICY(exdev))
-    (POLICY(ff))
-    (POLICY(ffwp))
-    (POLICY(fwfs))
-    (POLICY(lfs))
-    (POLICY(mfs))
-    (POLICY(newest))
-    (POLICY(rand));
+    (POLICY(invalid,DOESNT_PRESERVE_PATH))
+    (POLICY(all,DOESNT_PRESERVE_PATH))
+    (POLICY(einval,DOESNT_PRESERVE_PATH))
+    (POLICY(enosys,DOESNT_PRESERVE_PATH))
+    (POLICY(enotsup,DOESNT_PRESERVE_PATH))
+    (POLICY(eplfs,PRESERVES_PATH))
+    (POLICY(epmfs,PRESERVES_PATH))
+    (POLICY(erofs,DOESNT_PRESERVE_PATH))
+    (POLICY(exdev,DOESNT_PRESERVE_PATH))
+    (POLICY(ff,DOESNT_PRESERVE_PATH))
+    (POLICY(ffwp,DOESNT_PRESERVE_PATH))
+    (POLICY(fwfs,DOESNT_PRESERVE_PATH))
+    (POLICY(lfs,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];
 
@@ -51,6 +54,7 @@ namespace mergerfs
   CONST_POLICY(einval);
   CONST_POLICY(enosys);
   CONST_POLICY(enotsup);
+  CONST_POLICY(eplfs);
   CONST_POLICY(epmfs);
   CONST_POLICY(erofs);
   CONST_POLICY(exdev);

src/policy.hpp

@@ -39,6 +39,7 @@ namespace mergerfs
           einval,
           enosys,
           enotsup,
+          eplfs,
           epmfs,
           erofs,
           exdev,
@@ -95,6 +96,7 @@ namespace mergerfs
       static int einval(CType,cstrvec&,const char*,csize_t,cstrptrvec&);
       static int enosys(CType,cstrvec&,const char *,csize_t,cstrptrvec&);
       static int enotsup(CType,cstrvec&,const char *,csize_t,cstrptrvec&);
+      static int eplfs(CType,cstrvec&,const char *,csize_t,cstrptrvec&);
       static int epmfs(CType,cstrvec&,const char *,csize_t,cstrptrvec&);
       static int erofs(CType,cstrvec&,const char *,csize_t,cstrptrvec&);
       static int exdev(CType,cstrvec&,const char *,csize_t,cstrptrvec&);
@@ -112,24 +114,34 @@ namespace mergerfs
     Enum::Type  _enum;
     std::string _str;
     Func::Ptr   _func;
+    bool        _path_preserving;
 
   public:
     Policy()
       : _enum(invalid),
         _str(invalid),
-        _func(invalid)
+        _func(invalid),
+        _path_preserving(false)
     {
     }
 
     Policy(const Enum::Type   enum_,
            const std::string &str_,
-           const Func::Ptr    func_)
+           const Func::Ptr    func_,
+           const bool         path_preserving_)
       : _enum(enum_),
         _str(str_),
-        _func(func_)
+        _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; }
@@ -162,6 +174,7 @@ namespace mergerfs
     static const Policy &einval;
     static const Policy &enosys;
     static const Policy &enotsup;
+    static const Policy &eplfs;
     static const Policy &epmfs;
     static const Policy &erofs;
     static const Policy &exdev;

src/policy_eplfs.cpp

@@ -0,0 +1,108 @@
+/*
+  Copyright (c) 2016, 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.
+*/
+
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <sys/statvfs.h>
+
+#include <string>
+#include <vector>
+
+#include "fs_path.hpp"
+#include "policy.hpp"
+
+using std::string;
+using std::vector;
+using std::size_t;
+using mergerfs::Policy;
+using mergerfs::Category;
+typedef struct statvfs statvfs_t;
+
+static
+void
+_calc_lfs(const statvfs_t  &fsstats,
+          const string     *basepath,
+          const size_t      minfreespace,
+          fsblkcnt_t       &lfs,
+          const string    *&lfsbasepath)
+{
+  fsblkcnt_t spaceavail;
+
+  spaceavail = (fsstats.f_frsize * fsstats.f_bavail);
+  if((spaceavail > minfreespace) && (spaceavail < lfs))
+    {
+      lfs         = spaceavail;
+      lfsbasepath = basepath;
+    }
+}
+
+static
+int
+_eplfs(const Category::Enum::Type  type,
+       const vector<string>       &basepaths,
+       const char                 *fusepath,
+       const size_t                minfreespace,
+       vector<const string*>      &paths)
+{
+  int rv;
+  string fullpath;
+  statvfs_t fsstats;
+  fsblkcnt_t eplfs;
+  const string *eplfsbasepath;
+
+  eplfs = -1;
+  eplfsbasepath = NULL;
+  for(size_t i = 0, ei = basepaths.size(); i != ei; i++)
+    {
+      const string *basepath = &basepaths[i];
+
+      fs::path::make(basepath,fusepath,fullpath);
+
+      rv = ::statvfs(fullpath.c_str(),&fsstats);
+      if(rv == 0)
+        _calc_lfs(fsstats,basepath,minfreespace,eplfs,eplfsbasepath);
+    }
+
+  if(eplfsbasepath == NULL)
+    return -ENOENT;
+
+  paths.push_back(eplfsbasepath);
+
+  return 0;
+}
+
+namespace mergerfs
+{
+  int
+  Policy::Func::eplfs(const Category::Enum::Type  type,
+                      const vector<string>       &basepaths,
+                      const char                 *fusepath,
+                      const size_t                minfreespace,
+                      vector<const string*>     &paths)
+  {
+    int rv;
+    const size_t minfs =
+      ((type == Category::Enum::create) ? minfreespace : 0);
+
+    rv = _eplfs(type,basepaths,fusepath,minfs,paths);
+    if(rv != 0)
+      rv = Policy::Func::lfs(type,basepaths,fusepath,minfreespace,paths);
+
+    return rv;
+  }
+}

src/rename.cpp

@@ -275,16 +275,16 @@ namespace mergerfs
       const ugid::Set          ugid(fc->uid,fc->gid);
       const rwlock::ReadGuard  readlock(&config.srcmountslock);
 
-      if(config.create != Policy::epmfs)
-        return _rename_create_path(config.rename,
+      if(config.create->path_preserving())
+        return _rename_preserve_path(config.getattr,
+                                     config.rename,
                                      config.create,
                                      config.srcmounts,
                                      config.minfreespace,
                                      oldpath,
                                      newpath);
 
-      return _rename_preserve_path(config.getattr,
-                                   config.rename,
+      return _rename_create_path(config.rename,
                                  config.create,
                                  config.srcmounts,
                                  config.minfreespace,