3 files changed, 23 insertions, 2 deletions
diff --git a/lib/kernel/src/file.erl b/lib/kernel/src/file.erl
index 46ffa9d708..5da359fdf1 100644
--- a/lib/kernel/src/file.erl
+++ b/lib/kernel/src/file.erl
@@ -40,7 +40,7 @@
 	 read/2, write/2, 
 	 pread/2, pread/3, pwrite/2, pwrite/3,
 	 read_line/1,
-	 position/2, truncate/1, sync/1,
+	 position/2, truncate/1, datasync/1, sync/1,
 	 copy/2, copy/3]).
 %% High level operations
 -export([consult/1, path_consult/2]).
@@ -472,6 +472,16 @@ pwrite(#file_descriptor{module = Module} = Handle, Offs, Bytes) ->
 pwrite(_, _, _) ->
     {error, badarg}.
 
+-spec datasync(File :: io_device()) -> 'ok' | {'error', posix()}.
+
+datasync(File) when is_pid(File) ->
+    R = file_request(File, datasync),
+    wait_file_reply(File, R);
+datasync(#file_descriptor{module = Module} = Handle) ->
+    Module:datasync(Handle);
+datasync(_) ->
+    {error, badarg}.
+
 -spec sync(File :: io_device()) -> 'ok' | {'error', posix()}.
 
 sync(File) when is_pid(File) ->
diff --git a/lib/kernel/src/file_io_server.erl b/lib/kernel/src/file_io_server.erl
index 3ac35a209d..d0b30192b3 100644
--- a/lib/kernel/src/file_io_server.erl
+++ b/lib/kernel/src/file_io_server.erl
@@ -219,6 +219,14 @@ file_request({pwrite,At,Data},
 	Reply ->
 	    std_reply(Reply, State)
     end;
+file_request(datasync,
+	     #state{handle=Handle}=State) ->
+    case ?PRIM_FILE:datasync(Handle) of
+	{error,_}=Reply ->
+	    {stop,normal,Reply,State};
+	Reply ->
+	    {reply,Reply,State}
+    end;
 file_request(sync, 
 	     #state{handle=Handle}=State) ->
     case ?PRIM_FILE:sync(Handle) of
diff --git a/lib/kernel/src/ram_file.erl b/lib/kernel/src/ram_file.erl
index d996650948..0230cb4e0a 100644
--- a/lib/kernel/src/ram_file.erl
+++ b/lib/kernel/src/ram_file.erl
@@ -24,7 +24,7 @@
 -export([open/2, close/1]).
 -export([write/2, read/2, copy/3,
 	 pread/2, pread/3, pwrite/2, pwrite/3, 
-	 position/2, truncate/1, sync/1]).
+	 position/2, truncate/1, datasync/1, sync/1]).
 
 %% Specialized file operations
 -export([get_size/1, get_file/1, set_file/2, get_file_close/1]).
@@ -60,6 +60,7 @@
 -define(RAM_FILE_TRUNCATE,       14).
 -define(RAM_FILE_PREAD,          17).
 -define(RAM_FILE_PWRITE,         18).
+-define(RAM_FILE_FDATASYNC,      19).
 
 %% Other operations
 -define(RAM_FILE_GET,            30).
@@ -167,6 +168,8 @@ copy(#file_descriptor{module = ?MODULE} = Source,
     %% XXX Should be moved down to the driver for optimization.
     file:copy_opened(Source, Dest, Length).
 
+datasync(#file_descriptor{module = ?MODULE, data = Port}) ->
+    call_port(Port, <<?RAM_FILE_FDATASYNC>>).
 
 sync(#file_descriptor{module = ?MODULE, data = Port}) -> 
     call_port(Port, <<?RAM_FILE_FSYNC>>).