ignore drives mounted as readonly from create policies. closes #224

src/fs.cpp

@@ -31,28 +31,76 @@
 #include "fs_attr.hpp"
 #include "fs_path.hpp"
 #include "fs_xattr.hpp"
+#include "statvfs_util.hpp"
 #include "str.hpp"
+#include "success_fail.hpp"
 
 using std::string;
 using std::vector;
 
 namespace fs
 {
+  bool
+  exists(const string &path,
+         struct stat  &st)
+  {
+    int rv;
+
+    rv = ::lstat(path.c_str(),&st);
+
+    return LSTAT_SUCCEEDED(rv);
+  }
+
+  bool
+  exists(const string   &path,
+         struct statvfs &st)
+  {
+    int rv;
+
+    rv = ::statvfs(path.c_str(),&st);
+
+    return STATVFS_SUCCEEDED(rv);
+  }
+
+  bool
+  exists(const string &path)
+  {
+    struct stat st;
+
+    return exists(path,st);
+  }
+
+  bool
+  exists_on_rw_fs(const string   &path,
+                  struct statvfs &st)
+  {
+    int rv;
+
+    rv = ::statvfs(path.c_str(),&st);
+
+    return (STATVFS_SUCCEEDED(rv) && !StatVFS::readonly(st));
+  }
+
+  bool
+  exists_on_rw_fs(const string &path)
+  {
+    struct statvfs st;
+
+    return exists_on_rw_fs(path,st);
+  }
+
   void
   findallfiles(const vector<string> &srcmounts,
                const char           *fusepath,
                vector<string>       &paths)
   {
-    int rv;
     string fullpath;
-    struct stat st;
 
     for(size_t i = 0, ei = srcmounts.size(); i != ei; i++)
       {
         fs::path::make(&srcmounts[i],fusepath,fullpath);
 
-        rv = ::lstat(fullpath.c_str(),&st);
-        if(rv == 0)
+        if(fs::exists(fullpath))
           paths.push_back(fullpath);
       }
   }
@@ -145,16 +193,14 @@ namespace fs
     mfsidx = -1;
     for(size_t i = 0, ei = basepaths.size(); i != ei; i++)
       {
-        int rv;
-        struct statvfs fsstats;
+        struct statvfs st;
         const string &basepath = basepaths[i];
 
-        rv = ::statvfs(basepath.c_str(),&fsstats);
-        if(rv == 0)
+        if(fs::exists(basepath,st))
           {
             fsblkcnt_t spaceavail;
 
-            spaceavail = (fsstats.f_frsize * fsstats.f_bavail);
+            spaceavail = StatVFS::spaceavail(st);
             if((spaceavail > mfs) && (spaceavail >= minfreespace))
               {
                 mfs    = spaceavail;
@@ -170,4 +216,23 @@ namespace fs
 
     return 0;
   }
+
+  bool
+  available(const string   &path,
+            const bool      needswritablefs,
+            struct statvfs &st)
+  {
+    return (needswritablefs ?
+            fs::exists_on_rw_fs(path,st) :
+            fs::exists(path,st));
+  }
+
+  bool
+  available(const string &path,
+            const bool    needswritablefs)
+  {
+    return (needswritablefs ?
+            fs::exists_on_rw_fs(path) :
+            fs::exists(path));
+  }
 };

src/fs.hpp

@@ -26,6 +26,16 @@ namespace fs
   using std::string;
   using std::vector;
 
+  bool exists(const string &path,
+              struct stat  &st);
+  bool exists(const string   &path,
+              struct statvfs &st);
+  bool exists(const string &path);
+
+  bool exists_on_rw_fs(const string   &path,
+                       struct statvfs &st);
+  bool exists_on_rw_fs(const string &path);
+
   void findallfiles(const vector<string> &srcmounts,
                     const char           *fusepath,
                     vector<string>       &paths);
@@ -45,6 +55,13 @@ namespace fs
   int mfs(const vector<string> &srcs,
           const size_t          minfreespace,
           string               &path);
+
+  bool available(const string &path,
+                 const bool    needswritablefs);
+
+  bool available(const string   &path,
+                 const bool      needswritablefs,
+                 struct statvfs &st);
 };
 
 #endif // __FS_HPP__

src/policy_all.cpp

@@ -14,17 +14,14 @@
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
 #include <errno.h>
 
 #include <string>
 #include <vector>
 
+#include "fs.hpp"
 #include "fs_path.hpp"
 #include "policy.hpp"
-#include "success_fail.hpp"
 
 using std::string;
 using std::vector;
@@ -34,10 +31,9 @@ static
 int
 _all(const vector<string>  &basepaths,
      const char            *fusepath,
+     const bool             needswritablefs,
      vector<const string*> &paths)
 {
-  int rv;
-  struct stat st;
   string fullpath;
 
   for(size_t i = 0, ei = basepaths.size(); i != ei; i++)
@@ -46,8 +42,9 @@ _all(const vector<string>  &basepaths,
 
       fs::path::make(basepath,fusepath,fullpath);
 
-      rv = ::lstat(fullpath.c_str(),&st);
-      if(LSTAT_SUCCEEDED(rv))
+      if(!fs::available(fullpath,needswritablefs))
+        continue;
+
       paths.push_back(basepath);
     }
 
@@ -68,7 +65,9 @@ namespace mergerfs
   {
     const char *fp =
       ((type == Category::Enum::create) ? "" : fusepath);
+    const bool needswritablefs =
+      (type == Category::Enum::create);
 
-    return _all(basepaths,fp,paths);
+    return _all(basepaths,fp,needswritablefs,paths);
   }
 }

src/policy_eplfs.cpp

@@ -15,28 +15,25 @@
 */
 
 #include <errno.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
 #include <sys/statvfs.h>
 
 #include <string>
 #include <vector>
 
+#include "fs.hpp"
 #include "fs_path.hpp"
 #include "policy.hpp"
-#include "success_fail.hpp"
+#include "statvfs_util.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,
+_calc_lfs(const struct statvfs  &st,
           const string          *basepath,
           const size_t           minfreespace,
           fsblkcnt_t            &lfs,
@@ -44,7 +41,7 @@ _calc_lfs(const statvfs_t  &fsstats,
 {
   fsblkcnt_t spaceavail;
 
-  spaceavail = (fsstats.f_frsize * fsstats.f_bavail);
+  spaceavail = StatVFS::spaceavail(st);
   if((spaceavail > minfreespace) && (spaceavail < lfs))
     {
       lfs         = spaceavail;
@@ -54,15 +51,14 @@ _calc_lfs(const statvfs_t  &fsstats,
 
 static
 int
-_eplfs(const Category::Enum::Type  type,
-       const vector<string>       &basepaths,
+_eplfs(const vector<string>  &basepaths,
        const char            *fusepath,
        const size_t           minfreespace,
+       const bool             needswritablefs,
        vector<const string*> &paths)
 {
-  int rv;
   string fullpath;
-  statvfs_t fsstats;
+  struct statvfs st;
   fsblkcnt_t eplfs;
   const string *eplfsbasepath;
 
@@ -74,9 +70,10 @@ _eplfs(const Category::Enum::Type  type,
 
       fs::path::make(basepath,fusepath,fullpath);
 
-      rv = ::statvfs(fullpath.c_str(),&fsstats);
-      if(STATVFS_SUCCEEDED(rv))
-        _calc_lfs(fsstats,basepath,minfreespace,eplfs,eplfsbasepath);
+      if(!fs::available(fullpath,needswritablefs,st))
+        continue;
+
+      _calc_lfs(st,basepath,minfreespace,eplfs,eplfsbasepath);
     }
 
   if(eplfsbasepath == NULL)
@@ -97,10 +94,12 @@ namespace mergerfs
                       vector<const string*>      &paths)
   {
     int rv;
+    const bool needswritablefs =
+      (type == Category::Enum::create);
     const size_t minfs =
       ((type == Category::Enum::create) ? minfreespace : 0);
 
-    rv = _eplfs(type,basepaths,fusepath,minfs,paths);
+    rv = _eplfs(basepaths,fusepath,minfs,needswritablefs,paths);
     if(POLICY_FAILED(rv))
       rv = Policy::Func::lfs(type,basepaths,fusepath,minfreespace,paths);
 

src/policy_epmfs.cpp

@@ -15,28 +15,25 @@
 */
 
 #include <errno.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
 #include <sys/statvfs.h>
 
 #include <string>
 #include <vector>
 
+#include "fs.hpp"
 #include "fs_path.hpp"
 #include "policy.hpp"
-#include "success_fail.hpp"
+#include "statvfs_util.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_mfs(const statvfs_t  &fsstats,
+_calc_mfs(const struct statvfs  &st,
           const string          *basepath,
           const size_t           minfreespace,
           fsblkcnt_t            &mfs,
@@ -44,7 +41,7 @@ _calc_mfs(const statvfs_t  &fsstats,
 {
   fsblkcnt_t spaceavail;
 
-  spaceavail = (fsstats.f_frsize * fsstats.f_bavail);
+  spaceavail = StatVFS::spaceavail(st);
   if((spaceavail > minfreespace) && (spaceavail > mfs))
     {
       mfs         = spaceavail;
@@ -57,11 +54,11 @@ int
 _epmfs(const vector<string>  &basepaths,
        const char            *fusepath,
        const size_t           minfreespace,
+       const bool             needswritablefs,
        vector<const string*> &paths)
 {
-  int rv;
   string fullpath;
-  statvfs_t fsstats;
+  struct statvfs st;
   fsblkcnt_t epmfs;
   const string *epmfsbasepath;
 
@@ -73,9 +70,10 @@ _epmfs(const vector<string>  &basepaths,
 
       fs::path::make(basepath,fusepath,fullpath);
 
-      rv = ::statvfs(fullpath.c_str(),&fsstats);
-      if(STATVFS_SUCCEEDED(rv))
-        _calc_mfs(fsstats,basepath,minfreespace,epmfs,epmfsbasepath);
+      if(!fs::available(fullpath,needswritablefs,st))
+        continue;
+
+      _calc_mfs(st,basepath,minfreespace,epmfs,epmfsbasepath);
     }
 
   if(epmfsbasepath == NULL)
@@ -98,8 +96,10 @@ namespace mergerfs
     int rv;
     const size_t minfs =
       ((type == Category::Enum::create) ? minfreespace : 0);
+    const bool needswritablefs =
+      (type == Category::Enum::create);
 
-    rv = _epmfs(basepaths,fusepath,minfs,paths);
+    rv = _epmfs(basepaths,fusepath,minfs,needswritablefs,paths);
     if(POLICY_FAILED(rv))
       rv = Policy::Func::mfs(type,basepaths,fusepath,minfreespace,paths);
 

src/policy_ff.cpp

@@ -14,17 +14,16 @@
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
 #include <errno.h>
+#include <sys/statvfs.h>
 
 #include <string>
 #include <vector>
 
+#include "fs.hpp"
 #include "fs_path.hpp"
 #include "policy.hpp"
-#include "success_fail.hpp"
+#include "statvfs_util.hpp"
 
 using std::string;
 using std::vector;
@@ -34,11 +33,12 @@ static
 int
 _ff(const vector<string>  &basepaths,
     const char            *fusepath,
+    const bool             needswritablefs,
     vector<const string*> &paths)
 {
-  int rv;
   string fullpath;
-  struct stat st;
+  struct statvfs st;
+  const string *fallback = NULL;
 
   for(size_t i = 0, ei = basepaths.size(); i != ei; i++)
     {
@@ -46,15 +46,27 @@ _ff(const vector<string>  &basepaths,
 
       fs::path::make(basepath,fusepath,fullpath);
 
-      rv = ::lstat(fullpath.c_str(),&st);
-      if(LSTAT_FAILED(rv))
+      if(!fs::exists(fullpath,st))
         continue;
 
+      if(needswritablefs && StatVFS::readonly(st))
+        {
+          if(fallback == NULL)
+            fallback = basepath;
+          continue;
+        }
+
       paths.push_back(basepath);
 
       return POLICY_SUCCESS;
     }
 
+  if(fallback != NULL)
+    {
+      paths.push_back(fallback);
+      return POLICY_SUCCESS;
+    }
+
   return (errno=ENOENT,POLICY_FAIL);
 }
 
@@ -69,7 +81,9 @@ namespace mergerfs
   {
     const char *fp =
       ((type == Category::Enum::create) ? "" : fusepath);
+    const bool needswritablefs =
+      (type == Category::Enum::create);
 
-    return _ff(basepaths,fp,paths);
+    return _ff(basepaths,fp,needswritablefs,paths);
   }
 }

src/policy_ffwp.cpp

@@ -14,10 +14,8 @@
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
 #include <errno.h>
+#include <sys/stat.h>
 
 #include <string>
 #include <vector>

src/policy_fwfs.cpp

@@ -14,15 +14,16 @@
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
-#include <sys/statvfs.h>
 #include <errno.h>
+#include <sys/statvfs.h>
 
 #include <string>
 #include <vector>
 
+#include "fs.hpp"
 #include "fs_path.hpp"
 #include "policy.hpp"
-#include "success_fail.hpp"
+#include "statvfs_util.hpp"
 
 using std::string;
 using std::vector;
@@ -35,11 +36,11 @@ int
 _fwfs(const vector<string>  &basepaths,
       const char            *fusepath,
       const size_t           minfreespace,
+      const bool             needswritablefs,
       vector<const string*> &paths)
 {
-  int rv;
   string fullpath;
-  struct statvfs fsstats;
+  struct statvfs st;
 
   for(size_t i = 0, size = basepaths.size(); i != size; i++)
     {
@@ -47,20 +48,16 @@ _fwfs(const vector<string>  &basepaths,
 
       fs::path::make(basepath,fusepath,fullpath);
 
-      rv = ::statvfs(fullpath.c_str(),&fsstats);
-      if(STATVFS_SUCCEEDED(rv))
-        {
-          fsblkcnt_t spaceavail;
+      if(!fs::available(fullpath,needswritablefs,st))
+        continue;
 
-          spaceavail = (fsstats.f_frsize * fsstats.f_bavail);
-          if(spaceavail < minfreespace)
+      if(StatVFS::spaceavail(st) < minfreespace)
         continue;
 
       paths.push_back(basepath);
 
       return POLICY_SUCCESS;
     }
-    }
 
   return (errno=ENOENT,POLICY_FAIL);
 }
@@ -77,8 +74,10 @@ namespace mergerfs
     int rv;
     const char *fp =
       ((type == Category::Enum::create) ? "" : fusepath);
+    const bool needswritablefs =
+      (type == Category::Enum::create);
 
-    rv = _fwfs(basepaths,fp,minfreespace,paths);
+    rv = _fwfs(basepaths,fp,minfreespace,needswritablefs,paths);
     if(POLICY_FAILED(rv))
       rv = Policy::Func::mfs(type,basepaths,fusepath,minfreespace,paths);
 

src/policy_lfs.cpp

@@ -14,18 +14,16 @@
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/statvfs.h>
-#include <unistd.h>
 #include <errno.h>
+#include <sys/statvfs.h>
 
 #include <string>
 #include <vector>
 
+#include "fs.hpp"
 #include "fs_path.hpp"
 #include "policy.hpp"
-#include "success_fail.hpp"
+#include "statvfs_util.hpp"
 
 using std::string;
 using std::vector;
@@ -35,7 +33,7 @@ using mergerfs::Category;
 
 static
 void
-_calc_lfs(const struct statvfs  &fsstats,
+_calc_lfs(const struct statvfs  &st,
           const string          *basepath,
           const size_t           minfreespace,
           fsblkcnt_t            &lfs,
@@ -43,7 +41,7 @@ _calc_lfs(const struct statvfs  &fsstats,
 {
   fsblkcnt_t spaceavail;
 
-  spaceavail = (fsstats.f_frsize * fsstats.f_bavail);
+  spaceavail = StatVFS::spaceavail(st);
   if((spaceavail > minfreespace) && (spaceavail < lfs))
     {
       lfs         = spaceavail;
@@ -56,11 +54,11 @@ int
 _lfs(const vector<string>  &basepaths,
      const char            *fusepath,
      const size_t           minfreespace,
+     const bool             needswritablefs,
      vector<const string*> &paths)
 {
-  int rv;
   string fullpath;
-  struct statvfs fsstats;
+  struct statvfs st;
   fsblkcnt_t lfs;
   const string *lfsbasepath;
 
@@ -72,9 +70,10 @@ _lfs(const vector<string>  &basepaths,
 
       fs::path::make(basepath,fusepath,fullpath);
 
-      rv = ::statvfs(fullpath.c_str(),&fsstats);
-      if(STATVFS_SUCCEEDED(rv))
-        _calc_lfs(fsstats,basepath,minfreespace,lfs,lfsbasepath);
+      if(!fs::available(fullpath,needswritablefs,st))
+        continue;
+
+      _calc_lfs(st,basepath,minfreespace,lfs,lfsbasepath);
     }
 
   if(lfsbasepath == NULL)
@@ -97,8 +96,10 @@ namespace mergerfs
     int rv;
     const char *fp =
       ((type == Category::Enum::create) ? "" : fusepath);
+    const bool needswritablefs =
+      (type == Category::Enum::create);
 
-    rv = _lfs(basepaths,fp,minfreespace,paths);
+    rv = _lfs(basepaths,fp,minfreespace,needswritablefs,paths);
     if(POLICY_FAILED(rv))
       rv = Policy::Func::mfs(type,basepaths,fusepath,minfreespace,paths);
 

src/policy_mfs.cpp

@@ -14,15 +14,16 @@
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
-#include <sys/statvfs.h>
 #include <errno.h>
+#include <sys/statvfs.h>
 
 #include <string>
 #include <vector>
 
+#include "fs.hpp"
 #include "fs_path.hpp"
 #include "policy.hpp"
-#include "success_fail.hpp"
+#include "statvfs_util.hpp"
 
 using std::string;
 using std::vector;
@@ -30,14 +31,14 @@ using std::size_t;
 
 static
 void
-_calc_mfs(const struct statvfs  &fsstats,
+_calc_mfs(const struct statvfs  &st,
           const string          *basepath,
           fsblkcnt_t            &mfs,
           const string         *&mfsbasepath)
 {
   fsblkcnt_t spaceavail;
 
-  spaceavail = (fsstats.f_frsize * fsstats.f_bavail);
+  spaceavail = StatVFS::spaceavail(st);
   if(spaceavail > mfs)
     {
       mfs         = spaceavail;
@@ -49,11 +50,11 @@ static
 int
 _mfs(const vector<string>  &basepaths,
      const char            *fusepath,
+     const bool             needswritablefs,
      vector<const string*> &paths)
 {
-  int rv;
   string fullpath;
-  struct statvfs fsstats;
+  struct statvfs st;
   fsblkcnt_t mfs;
   const string *mfsbasepath;
 
@@ -65,9 +66,10 @@ _mfs(const vector<string>  &basepaths,
 
       fs::path::make(basepath,fusepath,fullpath);
 
-      rv = ::statvfs(fullpath.c_str(),&fsstats);
-      if(STATVFS_SUCCEEDED(rv))
-        _calc_mfs(fsstats,basepath,mfs,mfsbasepath);
+      if(!fs::available(fullpath,needswritablefs,st))
+        continue;
+
+      _calc_mfs(st,basepath,mfs,mfsbasepath);
     }
 
   if(mfsbasepath == NULL)
@@ -87,9 +89,16 @@ namespace mergerfs
                     const size_t                minfreespace,
                     vector<const string*>      &paths)
   {
+    int rv;
     const char *fp =
       ((type == Category::Enum::create) ? "" : fusepath);
+    const bool needswritablefs =
+      (type == Category::Enum::create);
+
+    rv = _mfs(basepaths,fp,needswritablefs,paths);
+    if(POLICY_FAILED(rv))
+      rv = Policy::Func::ff(type,basepaths,fusepath,minfreespace,paths);
 
-    return _mfs(basepaths,fp,paths);
+    return rv;
   }
 }

src/policy_newest.cpp

@@ -14,10 +14,9 @@
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
 #include <errno.h>
+#include <sys/stat.h>
+#include <sys/statvfs.h>
 
 #include <string>
 #include <vector>
@@ -26,6 +25,7 @@
 #include "fs_path.hpp"
 #include "policy.hpp"
 #include "success_fail.hpp"
+#include "statvfs_util.hpp"
 
 using std::string;
 using std::vector;
@@ -35,12 +35,12 @@ static
 int
 _newest(const vector<string>  &basepaths,
         const char            *fusepath,
+        const bool             needswritablefs,
         vector<const string*> &paths)
 {
-  int rv;
-  struct stat st;
-  string fullpath;
   time_t newest;
+  string fullpath;
+  struct stat st;
   const string *newestbasepath;
 
   newest = std::numeric_limits<time_t>::min();
@@ -51,13 +51,16 @@ _newest(const vector<string>  &basepaths,
 
       fs::path::make(basepath,fusepath,fullpath);
 
-      rv = ::lstat(fullpath.c_str(),&st);
-      if(LSTAT_SUCCEEDED(rv) && (st.st_mtime >= newest))
-        {
+      if(!fs::exists(fullpath,st))
+        continue;
+      if(st.st_mtime < newest)
+        continue;
+      if(needswritablefs && !fs::exists_on_rw_fs(fullpath))
+        continue;
+
       newest         = st.st_mtime;
       newestbasepath = basepath;
     }
-    }
 
   if(newestbasepath == NULL)
     return (errno=ENOENT,POLICY_FAIL);
@@ -76,6 +79,9 @@ namespace mergerfs
                        const size_t                minfreespace,
                        vector<const string*>      &paths)
   {
-    return _newest(basepaths,fusepath,paths);
+    const bool needswritablefs =
+      (type == Category::Enum::create);
+
+    return _newest(basepaths,fusepath,needswritablefs,paths);
   }
 }

src/statvfs_util.hpp

@@ -0,0 +1,55 @@
+/*
+  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 <sys/statvfs.h>
+
+#include <string>
+
+#include "success_fail.hpp"
+
+namespace StatVFS
+{
+  static
+  inline
+  bool
+  readonly(const struct statvfs &st)
+  {
+    return (st.f_flag & ST_RDONLY);
+  }
+
+  static
+  inline
+  bool
+  readonly(const std::string &path)
+  {
+    int rv;
+    struct statvfs st;
+
+    rv = ::statvfs(path.c_str(),&st);
+    if(STATVFS_FAILED(rv))
+      return false;
+
+    return readonly(st);
+  }
+
+  static
+  inline
+  fsblkcnt_t
+  spaceavail(const struct statvfs &st)
+  {
+    return (st.f_frsize * st.f_bavail);
+  }
+}