3 files changed, 24 insertions, 1 deletions
diff --git a/lib/kernel/src/file.erl b/lib/kernel/src/file.erl
index de3eaad5a1..16f2dde464 100644
--- a/lib/kernel/src/file.erl
+++ b/lib/kernel/src/file.erl
@@ -38,7 +38,7 @@
 %% Specialized
 -export([ipread_s32bu_p32bu/3]).
 %% Generic file contents.
--export([open/2, close/1, advise/4,
+-export([open/2, close/1, advise/4, allocate/3,
 	 read/2, write/2, 
 	 pread/2, pread/3, pwrite/2, pwrite/3,
 	 read_line/1,
@@ -490,6 +490,18 @@ advise(#file_descriptor{module = Module} = Handle, Offset, Length, Advise) ->
 advise(_, _, _, _) ->
     {error, badarg}.
 
+-spec allocate(File, Offset, Length) ->
+	'ok' | {'error', posix()} when
+      File :: io_device(),
+      Offset :: non_neg_integer(),
+      Length :: non_neg_integer().
+
+allocate(File, Offset, Length) when is_pid(File) ->
+    R = file_request(File, {allocate, Offset, Length}),
+    wait_file_reply(File, R);
+allocate(#file_descriptor{module = Module} = Handle, Offset, Length) ->
+    Module:allocate(Handle, Offset, Length).
+
 -spec read(IoDevice, Number) -> {ok, Data} | eof | {error, Reason} when
       IoDevice :: io_device() | atom(),
       Number :: non_neg_integer(),
diff --git a/lib/kernel/src/file_io_server.erl b/lib/kernel/src/file_io_server.erl
index acaffe1e41..fad2ed7fb3 100644
--- a/lib/kernel/src/file_io_server.erl
+++ b/lib/kernel/src/file_io_server.erl
@@ -211,6 +211,10 @@ file_request({advise,Offset,Length,Advise},
     Reply ->
         {reply,Reply,State}
     end;
+file_request({allocate, Offset, Length},
+         #state{handle = Handle} = State) ->
+    Reply = ?PRIM_FILE:allocate(Handle, Offset, Length),
+    {reply, Reply, State};
 file_request({pread,At,Sz}, 
 	     #state{handle=Handle,buf=Buf,read_mode=ReadMode}=State) ->
     case position(Handle, At, Buf) of
diff --git a/lib/kernel/src/ram_file.erl b/lib/kernel/src/ram_file.erl
index 48ea871433..ca881ff8a4 100644
--- a/lib/kernel/src/ram_file.erl
+++ b/lib/kernel/src/ram_file.erl
@@ -29,6 +29,7 @@
 %% Specialized file operations
 -export([get_size/1, get_file/1, set_file/2, get_file_close/1]).
 -export([compress/1, uncompress/1, uuencode/1, uudecode/1, advise/4]).
+-export([allocate/3]).
 
 -export([open_mode/1]).  %% used by ftp-file
 
@@ -72,6 +73,7 @@
 -define(RAM_FILE_UUDECODE,       36).
 -define(RAM_FILE_SIZE,           37).
 -define(RAM_FILE_ADVISE,         38).
+-define(RAM_FILE_ALLOCATE,       39).
 
 %% Open modes for RAM_FILE_OPEN
 -define(RAM_FILE_MODE_READ,       1).
@@ -383,6 +385,11 @@ advise(#file_descriptor{module = ?MODULE, data = Port}, Offset,
 advise(#file_descriptor{}, _Offset, _Length, _Advise) ->
     {error, enotsup}.
 
+allocate(#file_descriptor{module = ?MODULE, data = Port}, Offset, Length) ->
+    call_port(Port, <<?RAM_FILE_ALLOCATE, Offset:64/signed, Length:64/signed>>);
+allocate(#file_descriptor{}, _Offset, _Length) ->
+    {error, enotsup}.
+
 
 
 %%%-----------------------------------------------------------------