add flush callback. closes #16

src/flush.cpp

@@ -0,0 +1,61 @@
+/*
+   The MIT License (MIT)
+
+   Copyright (c) 2014 Antonio SJ Musumeci <trapexit@spawn.link>
+
+   Permission is hereby granted, free of charge, to any person obtaining a copy
+   of this software and associated documentation files (the "Software"), to deal
+   in the Software without restriction, including without limitation the rights
+   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+   copies of the Software, and to permit persons to whom the Software is
+   furnished to do so, subject to the following conditions:
+
+   The above copyright notice and this permission notice shall be included in
+   all copies or substantial portions of the Software.
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+   THE SOFTWARE.
+*/
+
+#include <fuse.h>
+
+#include <unistd.h>
+#include <errno.h>
+
+#include "ugid.hpp"
+#include "fileinfo.hpp"
+
+static
+int
+_flush(const int fd)
+{
+  int rv;
+
+  rv = dup(fd);
+  if(rv == -1)
+    errno = EIO;
+  else
+    rv = close(rv);
+
+  return ((rv == -1) ? -errno : 0);
+}
+
+namespace mergerfs
+{
+  namespace flush
+  {
+    int
+    flush(const char            *path,
+          struct fuse_file_info *fi)
+    {
+      const ugid::SetResetGuard ugid;
+
+      return _flush(((FileInfo*)fi->fh)->fd);
+    }
+  }
+}

src/flush.hpp

@@ -0,0 +1,33 @@
+/*
+   The MIT License (MIT)
+
+   Copyright (c) 2014 Antonio SJ Musumeci <trapexit@spawn.link>
+
+   Permission is hereby granted, free of charge, to any person obtaining a copy
+   of this software and associated documentation files (the "Software"), to deal
+   in the Software without restriction, including without limitation the rights
+   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+   copies of the Software, and to permit persons to whom the Software is
+   furnished to do so, subject to the following conditions:
+
+   The above copyright notice and this permission notice shall be included in
+   all copies or substantial portions of the Software.
+
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+   THE SOFTWARE.
+*/
+
+namespace mergerfs
+{
+  namespace flush
+  {
+    int
+    flush(const char            *path,
+          struct fuse_file_info *fi);
+  }
+}

src/mergerfs.cpp

@@ -40,6 +40,7 @@
 #include "create.hpp"
 #include "fallocate.hpp"
 #include "fgetattr.hpp"
+#include "flush.hpp"
 #include "fsync.hpp"
 #include "ftruncate.hpp"
 #include "getattr.hpp"
@@ -85,7 +86,7 @@ get_fuse_operations()
   ops.fallocate   = mergerfs::fallocate::fallocate;
   ops.fgetattr    = mergerfs::fgetattr::fgetattr;
   ops.flock       = NULL;
-  ops.flush       = NULL;       /* called on close() of fd */
+  ops.flush       = mergerfs::flush::flush;
   ops.fsync       = mergerfs::fsync::fsync;
   ops.fsyncdir    = NULL;
   ops.ftruncate   = mergerfs::ftruncate::ftruncate;