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-rw-r--r--erts/configure.in37
-rw-r--r--erts/emulator/drivers/common/efile_drv.c31
-rw-r--r--erts/emulator/drivers/common/erl_efile.h1
-rw-r--r--erts/emulator/drivers/common/ram_file_drv.c8
-rw-r--r--erts/emulator/drivers/unix/unix_efile.c92
-rw-r--r--erts/emulator/drivers/win32/win_efile.c10
-rw-r--r--erts/preloaded/src/prim_file.erl8
-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
13 files changed, 363 insertions, 7 deletions
diff --git a/erts/configure.in b/erts/configure.in
index 3256b0cb59..be9a753f7f 100644
--- a/erts/configure.in
+++ b/erts/configure.in
@@ -1075,8 +1075,43 @@ fi
AC_SUBST(ERTS_BUILD_SMP_EMU)
-AC_CHECK_FUNCS([posix_fadvise])
+AC_CHECK_FUNCS([posix_fadvise, fallocate])
+AC_CHECK_HEADERS([linux/falloc.h])
+dnl * Old glibcs have broken posix_fallocate(). Make sure not to use it.
+dnl * It may also be broken in AIX.
+AC_CACHE_CHECK([whether posix_fallocate() works],i_cv_posix_fallocate_works,[
+ AC_TRY_RUN([
+ #if !defined(__sun) && !defined(__sun__)
+ #define _XOPEN_SOURCE 600
+ #endif
+ #include <stdio.h>
+ #include <stdlib.h>
+ #include <fcntl.h>
+ #include <unistd.h>
+ #if defined(__GLIBC__) && (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ < 7))
+ possibly broken posix_fallocate
+ #endif
+ int main() {
+ int fd = creat("conftest.temp", 0600);
+ int ret;
+ if (-1 == fd) {
+ perror("creat()");
+ return 2;
+ }
+ ret = posix_fallocate(fd, 1024, 1024) < 0 ? 1 : 0;
+ unlink("conftest.temp");
+ return ret;
+ }
+ ], [
+ i_cv_posix_fallocate_works=yes
+ ], [
+ i_cv_posix_fallocate_works=no
+ ])
+])
+if test $i_cv_posix_fallocate_works = yes; then
+ AC_DEFINE(HAVE_POSIX_FALLOCATE,, Define if you have a working posix_fallocate())
+fi
#
# Figure out if the emulator should use threads. The default is set above
diff --git a/erts/emulator/drivers/common/efile_drv.c b/erts/emulator/drivers/common/efile_drv.c
index 912f5d3d8b..2c38e7256a 100644
--- a/erts/emulator/drivers/common/efile_drv.c
+++ b/erts/emulator/drivers/common/efile_drv.c
@@ -56,6 +56,7 @@
#define FILE_FDATASYNC 30
#define FILE_FADVISE 31
#define FILE_SENDFILE 32
+#define FILE_FALLOCATE 33
/* Return codes */
@@ -503,6 +504,10 @@ struct t_data
Uint64 written;
} sendfile;
#endif /* HAVE_SENDFILE */
+ struct {
+ Sint64 offset;
+ Sint64 length;
+ } fallocate;
} c;
char b[1];
};
@@ -1953,6 +1958,17 @@ static int flush_sendfile(file_descriptor *desc,void *_) {
#endif /* HAVE_SENDFILE */
+static void invoke_fallocate(void *data)
+{
+ struct t_data *d = (struct t_data *) data;
+ int fd = (int) d->fd;
+ Sint64 offset = d->c.fallocate.offset;
+ Sint64 length = d->c.fallocate.length;
+
+ d->again = 0;
+ d->result_ok = efile_fallocate(&d->errInfo, fd, offset, length);
+}
+
static void free_readdir(void *data)
{
struct t_data *d = (struct t_data *) data;
@@ -2348,6 +2364,7 @@ file_async_ready(ErlDrvData e, ErlDrvThreadData data)
case FILE_RENAME:
case FILE_WRITE_INFO:
case FILE_FADVISE:
+ case FILE_FALLOCATE:
reply(desc, d->result_ok, &d->errInfo);
free_data(data);
break;
@@ -2958,6 +2975,20 @@ file_output(ErlDrvData e, char* buf, ErlDrvSizeT count)
goto done;
}
+ case FILE_FALLOCATE:
+ {
+ d = EF_SAFE_ALLOC(sizeof(struct t_data));
+
+ d->fd = fd;
+ d->command = command;
+ d->invoke = invoke_fallocate;
+ d->free = free_data;
+ d->level = 2;
+ d->c.fallocate.offset = get_int64((uchar*) buf);
+ d->c.fallocate.length = get_int64(((uchar*) buf) + sizeof(Sint64));
+ goto done;
+ }
+
}
/*
diff --git a/erts/emulator/drivers/common/erl_efile.h b/erts/emulator/drivers/common/erl_efile.h
index 69ad02633c..b29b4f971c 100644
--- a/erts/emulator/drivers/common/erl_efile.h
+++ b/erts/emulator/drivers/common/erl_efile.h
@@ -185,3 +185,4 @@ int efile_fadvise(Efile_error* errInfo, int fd, Sint64 offset, Sint64 length,
int efile_sendfile(Efile_error* errInfo, int in_fd, int out_fd,
off_t *offset, Uint64 *nbytes, struct t_sendfile_hdtl *hdtl);
#endif /* HAVE_SENDFILE */
+int efile_fallocate(Efile_error* errInfo, int fd, Sint64 offset, Sint64 length);
diff --git a/erts/emulator/drivers/common/ram_file_drv.c b/erts/emulator/drivers/common/ram_file_drv.c
index a109e40333..7f7cd7cd91 100644
--- a/erts/emulator/drivers/common/ram_file_drv.c
+++ b/erts/emulator/drivers/common/ram_file_drv.c
@@ -48,6 +48,7 @@
#define RAM_FILE_SIZE 37 /* get file size */
#define RAM_FILE_ADVISE 38 /* predeclare the access
* pattern for file data */
+#define RAM_FILE_ALLOCATE 39 /* allocate space for a file */
/* possible new operations include:
DES_ENCRYPT
DES_DECRYPT
@@ -720,6 +721,13 @@ static void rfile_command(ErlDrvData e, char* buf, ErlDrvSizeT count)
else
reply(f, 1, 0);
break;
+
+ case RAM_FILE_ALLOCATE:
+ if (f->flags == 0)
+ error_reply(f, EBADF);
+ else
+ reply(f, 1, 0);
+ break;
}
/*
* Ignore anything else -- let the caller hang.
diff --git a/erts/emulator/drivers/unix/unix_efile.c b/erts/emulator/drivers/unix/unix_efile.c
index cf7af71b92..558651fff9 100644
--- a/erts/emulator/drivers/unix/unix_efile.c
+++ b/erts/emulator/drivers/unix/unix_efile.c
@@ -22,6 +22,12 @@
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
+#if defined(HAVE_POSIX_FALLOCATE) && !defined(__sun) && !defined(__sun__)
+#define _XOPEN_SOURCE 600
+#endif
+#if !defined(_GNU_SOURCE) && defined(HAVE_LINUX_FALLOC_H)
+#define _GNU_SOURCE
+#endif
#include "sys.h"
#include "erl_driver.h"
#include "erl_efile.h"
@@ -41,9 +47,13 @@
#define DARWIN 1
#endif
-#ifdef DARWIN
+#if defined(DARWIN) || defined(HAVE_LINUX_FALLOC_H) || defined(HAVE_POSIX_FALLOCATE)
#include <fcntl.h>
-#endif /* DARWIN */
+#endif
+
+#ifdef HAVE_LINUX_FALLOC_H
+#include <linux/falloc.h>
+#endif
#ifdef SUNOS4
# define getcwd(buf, size) getwd(buf)
@@ -967,3 +977,81 @@ efile_sendfile(Efile_error* errInfo, int in_fd, int out_fd,
return check_error(retval, errInfo);
}
#endif /* HAVE_SENDFILE */
+
+#ifdef HAVE_POSIX_FALLOCATE
+static int
+call_posix_fallocate(int fd, Sint64 offset, Sint64 length)
+{
+ int ret;
+
+ /*
+ * On Linux and Solaris for example, posix_fallocate() returns
+ * a positive error number on error and it does not set errno.
+ * On FreeBSD however (9.0 at least), it returns -1 on error
+ * and it sets errno.
+ */
+ do {
+ ret = posix_fallocate(fd, (off_t) offset, (off_t) length);
+ if (ret > 0) {
+ errno = ret;
+ ret = -1;
+ }
+ } while (ret != 0 && errno == EINTR);
+
+ return ret;
+}
+#endif /* HAVE_POSIX_FALLOCATE */
+
+int
+efile_fallocate(Efile_error* errInfo, int fd, Sint64 offset, Sint64 length)
+{
+#if defined HAVE_FALLOCATE
+ /* Linux specific, more efficient than posix_fallocate. */
+ int ret;
+
+ do {
+ ret = fallocate(fd, FALLOC_FL_KEEP_SIZE, (off_t) offset, (off_t) length);
+ } while (ret != 0 && errno == EINTR);
+
+#if defined HAVE_POSIX_FALLOCATE
+ /* Fallback to posix_fallocate if available. */
+ if (ret != 0) {
+ ret = call_posix_fallocate(fd, offset, length);
+ }
+#endif
+
+ return check_error(ret, errInfo);
+#elif defined F_PREALLOCATE
+ /* Mac OS X specific, equivalent to posix_fallocate. */
+ int ret;
+ fstore_t fs;
+
+ memset(&fs, 0, sizeof(fs));
+ fs.fst_flags = F_ALLOCATECONTIG;
+ fs.fst_posmode = F_VOLPOSMODE;
+ fs.fst_offset = (off_t) offset;
+ fs.fst_length = (off_t) length;
+
+ ret = fcntl(fd, F_PREALLOCATE, &fs);
+
+ if (-1 == ret) {
+ fs.fst_flags = F_ALLOCATEALL;
+ ret = fcntl(fd, F_PREALLOCATE, &fs);
+
+#if defined HAVE_POSIX_FALLOCATE
+ /* Fallback to posix_fallocate if available. */
+ if (-1 == ret) {
+ ret = call_posix_fallocate(fd, offset, length);
+ }
+#endif
+ }
+
+ return check_error(ret, errInfo);
+#elif defined HAVE_POSIX_FALLOCATE
+ /* Other Unixes, use posix_fallocate if available. */
+ return check_error(call_posix_fallocate(fd, offset, length), errInfo);
+#else
+ errno = ENOTSUP;
+ return check_error(-1, errInfo);
+#endif
+}
diff --git a/erts/emulator/drivers/win32/win_efile.c b/erts/emulator/drivers/win32/win_efile.c
index dc7add01f7..f5011d11a5 100644
--- a/erts/emulator/drivers/win32/win_efile.c
+++ b/erts/emulator/drivers/win32/win_efile.c
@@ -1558,3 +1558,13 @@ efile_fadvise(Efile_error* errInfo, int fd, Sint64 offset,
errno = ERROR_SUCCESS;
return check_error(0, errInfo);
}
+
+int
+efile_fallocate(Efile_error* errInfo, int fd, Sint64 offset, Sint64 length)
+{
+ /* No file preallocation method available in Windows. */
+ errno = errno_map(ERROR_NOT_SUPPORTED);
+ SetLastError(ERROR_NOT_SUPPORTED);
+
+ return check_error(-1, errInfo);
+}
diff --git a/erts/preloaded/src/prim_file.erl b/erts/preloaded/src/prim_file.erl
index eafab1bae4..c412b7faf2 100644
--- a/erts/preloaded/src/prim_file.erl
+++ b/erts/preloaded/src/prim_file.erl
@@ -27,7 +27,7 @@
%% Generic file contents operations
-export([open/2, close/1, datasync/1, sync/1, advise/4, position/2, truncate/1,
write/2, pwrite/2, pwrite/3, read/2, read_line/1, pread/2, pread/3,
- copy/3, sendfile/10]).
+ copy/3, sendfile/10, allocate/3]).
%% Specialized file operations
-export([open/1, open/3]).
@@ -100,6 +100,7 @@
-define(FILE_FDATASYNC, 30).
-define(FILE_ADVISE, 31).
-define(FILE_SENDFILE, 32).
+-define(FILE_ALLOCATE, 33).
%% Driver responses
-define(FILE_RESP_OK, 0).
@@ -293,6 +294,11 @@ advise(#file_descriptor{module = ?MODULE, data = {Port, _}},
end.
%% Returns {error, Reason} | ok.
+allocate(#file_descriptor{module = ?MODULE, data = {Port, _}}, Offset, Length) ->
+ Cmd = <<?FILE_ALLOCATE, Offset:64/signed, Length:64/signed>>,
+ drv_command(Port, Cmd).
+
+%% Returns {error, Reason} | ok.
write(#file_descriptor{module = ?MODULE, data = {Port, _}}, Bytes) ->
case drv_command_nt(Port, [?FILE_WRITE,erlang:dt_prepend_vm_tag_data(Bytes)],undefined) of
{ok, _Size} ->
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) ->