Merge branch 'fdm/file-allocate/OTP-10680'

* fdm/file-allocate/OTP-10680:
  Update preloaded prim_file.beam
  erts: Fix xcomp configure for fallocate
  Add file:allocate/3 operation

6 files changed, 180 insertions, 3 deletions

diff --git a/lib/kernel/doc/src/file.xml b/lib/kernel/doc/src/file.xml
index 536b98b5f5..e30ade1bd2 100644
--- a/lib/kernel/doc/src/file.xml
+++ b/lib/kernel/doc/src/file.xml
@@ -170,6 +170,18 @@
       </desc>
     </func>
     <func>
+      <name name="allocate" arity="3"/>
+      <fsummary>Allocate file space</fsummary>
+      <desc>
+        <p><c>allocate/3</c> can be used to preallocate space for a file.</p>
+        <p>This function only succeeds in platforms that implement this
+          feature. When it succeeds, space is preallocated for the file but
+          the file size might not be updated. This behaviour depends on the
+          preallocation implementation. To guarantee the file size is updated
+          one must truncate the file to the new size.</p>
+      </desc>
+    </func>
+    <func>
       <name name="change_group" arity="2"/>
       <fsummary>Change group of a file</fsummary>
       <desc>
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}.
+
 
 
 %%%-----------------------------------------------------------------
diff --git a/lib/kernel/test/file_SUITE.erl b/lib/kernel/test/file_SUITE.erl
index 9c507fd437..914f0d6127 100644
--- a/lib/kernel/test/file_SUITE.erl
+++ b/lib/kernel/test/file_SUITE.erl
@@ -84,6 +84,8 @@
 
 -export([advise/1]).
 
+-export([allocate/1]).
+
 -export([standard_io/1,mini_server/1]).
 
 %% Debug exports
@@ -116,7 +118,7 @@ groups() ->
      {files, [],
       [{group, open}, {group, pos}, {group, file_info},
        {group, consult}, {group, eval}, {group, script},
-       truncate, sync, datasync, advise]},
+       truncate, sync, datasync, advise, allocate]},
      {open, [],
       [open1, old_modes, new_modes, path_open, close, access,
        read_write, pread_write, append, open_errors,
@@ -1617,6 +1619,74 @@ advise(Config) when is_list(Config) ->
     ?line test_server:timetrap_cancel(Dog),
     ok.
 
+allocate(suite) -> [];
+allocate(doc) -> "Tests that ?FILE_MODULE:allocate/3 at least doesn't crash.";
+allocate(Config) when is_list(Config) ->
+    ?line Dog = test_server:timetrap(test_server:seconds(5)),
+    ?line PrivDir = ?config(priv_dir, Config),
+    ?line Allocate = filename:join(PrivDir,
+			       atom_to_list(?MODULE)
+			       ++"_allocate.fil"),
+
+    Line1 = "Hello\n",
+    Line2 = "World!\n",
+
+    ?line {ok, Fd} = ?FILE_MODULE:open(Allocate, [write, binary]),
+    allocate_and_assert(Fd, 1, iolist_size([Line1, Line2])),
+    ?line ok = io:format(Fd, "~s", [Line1]),
+    ?line ok = io:format(Fd, "~s", [Line2]),
+    ?line ok = ?FILE_MODULE:close(Fd),
+
+    ?line {ok, Fd2} = ?FILE_MODULE:open(Allocate, [write, binary]),
+    allocate_and_assert(Fd2, 1, iolist_size(Line1)),
+    ?line ok = io:format(Fd2, "~s", [Line1]),
+    ?line ok = io:format(Fd2, "~s", [Line2]),
+    ?line ok = ?FILE_MODULE:close(Fd2),
+
+    ?line {ok, Fd3} = ?FILE_MODULE:open(Allocate, [write, binary]),
+    allocate_and_assert(Fd3, 1, iolist_size(Line1) + 1),
+    ?line ok = io:format(Fd3, "~s", [Line1]),
+    ?line ok = io:format(Fd3, "~s", [Line2]),
+    ?line ok = ?FILE_MODULE:close(Fd3),
+
+    ?line {ok, Fd4} = ?FILE_MODULE:open(Allocate, [write, binary]),
+    allocate_and_assert(Fd4, 1, 4 * iolist_size([Line1, Line2])),
+    ?line ok = io:format(Fd4, "~s", [Line1]),
+    ?line ok = io:format(Fd4, "~s", [Line2]),
+    ?line ok = ?FILE_MODULE:close(Fd4),
+
+    ?line [] = flush(),
+    ?line test_server:timetrap_cancel(Dog),
+    ok.
+
+allocate_and_assert(Fd, Offset, Length) ->
+    % Just verify that calls to ?PRIM_FILE:allocate/3 don't crash or have
+    % any other negative side effect. We can't really asssert against a
+    % specific return value, because support for file space pre-allocation
+    % depends on the OS, OS version and underlying filesystem.
+    %
+    % The Linux kernel added support for fallocate() in version 2.6.23,
+    % which currently works only for the ext4, ocfs2, xfs and btrfs file
+    % systems. posix_fallocate() is available in glibc as of version
+    % 2.1.94, but it was buggy until glibc version 2.7.
+    %
+    % Mac OS X, as of version 10.3, supports the fcntl operation F_PREALLOCATE.
+    %
+    % Solaris supports posix_fallocate() but only for the UFS file system
+    % apparently (not supported for ZFS).
+    %
+    % FreeBSD 9.0 is the first FreeBSD release supporting posix_fallocate().
+    %
+    % For Windows there's apparently no way to pre-allocate file space, at
+    % least with same semantics as posix_fallocate(), fallocate() and
+    % fcntl F_PREALLOCATE.
+    Result = ?FILE_MODULE:allocate(Fd, Offset, Length),
+    case os:type() of
+        {win32, _} ->
+            ?line {error, enotsup} = Result;
+        _ ->
+            ?line _ = Result
+    end.
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
diff --git a/lib/kernel/test/prim_file_SUITE.erl b/lib/kernel/test/prim_file_SUITE.erl
index a56746bbc4..4e93a593b3 100644
--- a/lib/kernel/test/prim_file_SUITE.erl
+++ b/lib/kernel/test/prim_file_SUITE.erl
@@ -57,6 +57,8 @@
 %% System probe functions that might be handy to check from the shell
 -export([unix_free/1]).
 
+-export([allocate/1]).
+
 -include_lib("test_server/include/test_server.hrl").
 -include_lib("kernel/include/file.hrl").
 
@@ -87,7 +89,7 @@ groups() ->
        cur_dir_1a, cur_dir_1b]},
      {files, [],
       [{group, open}, {group, pos}, {group, file_info},
-       truncate, sync, datasync, advise, large_write]},
+       truncate, sync, datasync, advise, large_write, allocate]},
      {open, [],
       [open1, modes, close, access, read_write, pread_write,
        append, exclusive]},
@@ -1359,6 +1361,76 @@ check_large_write(Dog, Fd, _, _, []) ->
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
+allocate(suite) -> [];
+allocate(doc) -> "Tests that ?PRIM_FILE:allocate/3 at least doesn't crash.";
+allocate(Config) when is_list(Config) ->
+    ?line Dog = test_server:timetrap(test_server:seconds(5)),
+    ?line PrivDir = ?config(priv_dir, Config),
+    ?line Allocate = filename:join(PrivDir,
+			       atom_to_list(?MODULE)
+			       ++"_allocate.fil"),
+
+    Line1 = "Hello\n",
+    Line2 = "World!\n",
+
+    ?line {ok, Fd} = ?PRIM_FILE:open(Allocate, [write, binary]),
+    allocate_and_assert(Fd, 1, iolist_size([Line1, Line2])),
+    ?line ok = ?PRIM_FILE:write(Fd, Line1),
+    ?line ok = ?PRIM_FILE:write(Fd, Line2),
+    ?line ok = ?PRIM_FILE:close(Fd),
+
+    ?line {ok, Fd2} = ?PRIM_FILE:open(Allocate, [write, binary]),
+    allocate_and_assert(Fd2, 1, iolist_size(Line1)),
+    ?line ok = ?PRIM_FILE:write(Fd2, Line1),
+    ?line ok = ?PRIM_FILE:write(Fd2, Line2),
+    ?line ok = ?PRIM_FILE:close(Fd2),
+
+    ?line {ok, Fd3} = ?PRIM_FILE:open(Allocate, [write, binary]),
+    allocate_and_assert(Fd3, 1, iolist_size(Line1) + 1),
+    ?line ok = ?PRIM_FILE:write(Fd3, Line1),
+    ?line ok = ?PRIM_FILE:write(Fd3, Line2),
+    ?line ok = ?PRIM_FILE:close(Fd3),
+
+    ?line {ok, Fd4} = ?PRIM_FILE:open(Allocate, [write, binary]),
+    allocate_and_assert(Fd4, 1, 4 * iolist_size([Line1, Line2])),
+    ?line ok = ?PRIM_FILE:write(Fd4, Line1),
+    ?line ok = ?PRIM_FILE:write(Fd4, Line2),
+    ?line ok = ?PRIM_FILE:close(Fd4),
+
+    ?line test_server:timetrap_cancel(Dog),
+    ok.
+
+allocate_and_assert(Fd, Offset, Length) ->
+    % Just verify that calls to ?PRIM_FILE:allocate/3 don't crash or have
+    % any other negative side effect. We can't really asssert against a
+    % specific return value, because support for file space pre-allocation
+    % depends on the OS, OS version and underlying filesystem.
+    %
+    % The Linux kernel added support for fallocate() in version 2.6.23,
+    % which currently works only for the ext4, ocfs2, xfs and btrfs file
+    % systems. posix_fallocate() is available in glibc as of version
+    % 2.1.94, but it was buggy until glibc version 2.7.
+    %
+    % Mac OS X, as of version 10.3, supports the fcntl operation F_PREALLOCATE.
+    %
+    % Solaris supports posix_fallocate() but only for the UFS file system
+    % apparently (not supported for ZFS).
+    %
+    % FreeBSD 9.0 is the first FreeBSD release supporting posix_fallocate().
+    %
+    % For Windows there's apparently no way to pre-allocate file space, at
+    % least with similar API/semantics as posix_fallocate(), fallocate() or
+    % fcntl F_PREALLOCATE.
+    Result = ?PRIM_FILE:allocate(Fd, Offset, Length),
+    case os:type() of
+        {win32, _} ->
+            ?line {error, enotsup} = Result;
+        _ ->
+            ?line _ = Result
+    end.
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
 delete_a(suite) -> [];
 delete_a(doc) -> [];
 delete_a(Config) when is_list(Config) ->