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-rw-r--r--lib/kernel/doc/src/file.xml12
-rw-r--r--lib/kernel/src/file.erl14
-rw-r--r--lib/kernel/src/file_io_server.erl4
-rw-r--r--lib/kernel/src/ram_file.erl7
-rw-r--r--lib/kernel/test/file_SUITE.erl72
-rw-r--r--lib/kernel/test/prim_file_SUITE.erl74
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) ->
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-27 15:34:48 +0000