Remove configure probe for fdatasync.

fdatasync() is in SUSv2, and all targeted Unix systems have it.  We have
a replacement function for Windows.

We retain the probe for the function declaration, which allows us to
supply the mysteriously missing declaration for macOS, and also for
Windows.  No need to keep a HAVE_FDATASYNC macro around.

Also rename src/port/fdatasync.c to win32fdatasync.c since it's only for
Windows.

Reviewed-by: Tom Lane <[email protected]>
Reviewed-by: Andres Freund <[email protected]>
Discussion: https://postgr.es/m/CA+hUKGJ3LHeP9w5Fgzdr4G8AnEtJ=z=p6hGDEm4qYGEUX5B6fQ@mail.gmail.com
Discussion: https://postgr.es/m/CA%2BhUKGJZJVO%3DiX%2Beb-PXi2_XS9ZRqnn_4URh0NUQOwt6-_51xQ%40mail.gmail.com

12 files changed, 15 insertions, 48 deletions

diff --git a/configure b/configure
index 21f4520f810..da28a6bb8b0 100755
--- a/configure
+++ b/configure
@@ -16039,7 +16039,7 @@ fi
 LIBS_including_readline="$LIBS"
 LIBS=`echo "$LIBS" | sed -e 's/-ledit//g' -e 's/-lreadline//g'`
 
-for ac_func in backtrace_symbols copyfile fdatasync getifaddrs getpeerucred inet_pton kqueue mbstowcs_l memset_s posix_fallocate ppoll pthread_is_threaded_np setproctitle setproctitle_fast strchrnul strsignal syncfs sync_file_range uselocale wcstombs_l
+for ac_func in backtrace_symbols copyfile getifaddrs getpeerucred inet_pton kqueue mbstowcs_l memset_s posix_fallocate ppoll pthread_is_threaded_np setproctitle setproctitle_fast strchrnul strsignal syncfs sync_file_range uselocale wcstombs_l
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
@@ -16930,12 +16930,6 @@ fi
 esac
 
   case " $LIBOBJS " in
-  *" fdatasync.$ac_objext "* ) ;;
-  *) LIBOBJS="$LIBOBJS fdatasync.$ac_objext"
- ;;
-esac
-
-  case " $LIBOBJS " in
   *" getrusage.$ac_objext "* ) ;;
   *) LIBOBJS="$LIBOBJS getrusage.$ac_objext"
  ;;
@@ -16978,6 +16972,12 @@ esac
 esac
 
   case " $LIBOBJS " in
+  *" win32fdatasync.$ac_objext "* ) ;;
+  *) LIBOBJS="$LIBOBJS win32fdatasync.$ac_objext"
+ ;;
+esac
+
+  case " $LIBOBJS " in
   *" win32link.$ac_objext "* ) ;;
   *) LIBOBJS="$LIBOBJS win32link.$ac_objext"
  ;;
diff --git a/configure.ac b/configure.ac
index a7ab6601790..fada092cf38 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1792,7 +1792,6 @@ LIBS=`echo "$LIBS" | sed -e 's/-ledit//g' -e 's/-lreadline//g'`
 AC_CHECK_FUNCS(m4_normalize([
 	backtrace_symbols
 	copyfile
-	fdatasync
 	getifaddrs
 	getpeerucred
 	inet_pton
@@ -1928,7 +1927,6 @@ if test "$PORTNAME" = "win32"; then
   AC_CHECK_FUNCS(_configthreadlocale)
   AC_REPLACE_FUNCS(gettimeofday)
   AC_LIBOBJ(dirmod)
-  AC_LIBOBJ(fdatasync)
   AC_LIBOBJ(getrusage)
   AC_LIBOBJ(kill)
   AC_LIBOBJ(open)
@@ -1936,6 +1934,7 @@ if test "$PORTNAME" = "win32"; then
   AC_LIBOBJ(win32dlopen)
   AC_LIBOBJ(win32env)
   AC_LIBOBJ(win32error)
+  AC_LIBOBJ(win32fdatasync)
   AC_LIBOBJ(win32link)
   AC_LIBOBJ(win32ntdll)
   AC_LIBOBJ(win32pread)
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index eb5115fd5a8..34f0150d1ee 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -168,9 +168,7 @@ const struct config_enum_entry sync_method_options[] = {
 #ifdef HAVE_FSYNC_WRITETHROUGH
 	{"fsync_writethrough", SYNC_METHOD_FSYNC_WRITETHROUGH, false},
 #endif
-#ifdef HAVE_FDATASYNC
 	{"fdatasync", SYNC_METHOD_FDATASYNC, false},
-#endif
 #ifdef O_SYNC
 	{"open_sync", SYNC_METHOD_OPEN, false},
 #endif
@@ -8015,12 +8013,10 @@ issue_xlog_fsync(int fd, XLogSegNo segno, TimeLineID tli)
 				msg = _("could not fsync write-through file \"%s\": %m");
 			break;
 #endif
-#ifdef HAVE_FDATASYNC
 		case SYNC_METHOD_FDATASYNC:
 			if (pg_fdatasync(fd) != 0)
 				msg = _("could not fdatasync file \"%s\": %m");
 			break;
-#endif
 		case SYNC_METHOD_OPEN:
 		case SYNC_METHOD_OPEN_DSYNC:
 			/* not reachable */
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index 5a2eb012381..ccb540d6178 100644
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -442,20 +442,12 @@ pg_fsync_writethrough(int fd)
 
 /*
  * pg_fdatasync --- same as fdatasync except does nothing if enableFsync is off
- *
- * Not all platforms have fdatasync; treat as fsync if not available.
  */
 int
 pg_fdatasync(int fd)
 {
 	if (enableFsync)
-	{
-#ifdef HAVE_FDATASYNC
 		return fdatasync(fd);
-#else
-		return fsync(fd);
-#endif
-	}
 	else
 		return 0;
 }
diff --git a/src/bin/pg_test_fsync/pg_test_fsync.c b/src/bin/pg_test_fsync/pg_test_fsync.c
index 8f0ef8e66b9..77f0db0376b 100644
--- a/src/bin/pg_test_fsync/pg_test_fsync.c
+++ b/src/bin/pg_test_fsync/pg_test_fsync.c
@@ -331,7 +331,6 @@ test_sync(int writes_per_op)
 	printf(LABEL_FORMAT, "fdatasync");
 	fflush(stdout);
 
-#ifdef HAVE_FDATASYNC
 	if ((tmpfile = open(filename, O_RDWR | PG_BINARY, 0)) == -1)
 		die("could not open output file");
 	START_TIMER;
@@ -347,9 +346,6 @@ test_sync(int writes_per_op)
 	}
 	STOP_TIMER;
 	close(tmpfile);
-#else
-	printf(NA_FORMAT, _("n/a"));
-#endif
 
 /*
  * Test fsync
diff --git a/src/include/access/xlogdefs.h b/src/include/access/xlogdefs.h
index 810cd1fd86a..49e581925c9 100644
--- a/src/include/access/xlogdefs.h
+++ b/src/include/access/xlogdefs.h
@@ -67,8 +67,7 @@ typedef uint16 RepOriginId;
 /*
  * This chunk of hackery attempts to determine which file sync methods
  * are available on the current platform, and to choose an appropriate
- * default method.  We assume that fsync() is always available, and that
- * configure determined whether fdatasync() is.
+ * default method.
  *
  * Note that we define our own O_DSYNC on Windows, but not O_SYNC.
  */
@@ -76,10 +75,8 @@ typedef uint16 RepOriginId;
 #define DEFAULT_SYNC_METHOD		PLATFORM_DEFAULT_SYNC_METHOD
 #elif defined(O_DSYNC) && (!defined(O_SYNC) || O_DSYNC != O_SYNC)
 #define DEFAULT_SYNC_METHOD		SYNC_METHOD_OPEN_DSYNC
-#elif defined(HAVE_FDATASYNC)
-#define DEFAULT_SYNC_METHOD		SYNC_METHOD_FDATASYNC
 #else
-#define DEFAULT_SYNC_METHOD		SYNC_METHOD_FSYNC
+#define DEFAULT_SYNC_METHOD		SYNC_METHOD_FDATASYNC
 #endif
 
 #endif							/* XLOG_DEFS_H */
diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
index 6505a842118..2a0d08d10f5 100644
--- a/src/include/pg_config.h.in
+++ b/src/include/pg_config.h.in
@@ -170,9 +170,6 @@
 /* Define to 1 if you have the `explicit_bzero' function. */
 #undef HAVE_EXPLICIT_BZERO
 
-/* Define to 1 if you have the `fdatasync' function. */
-#undef HAVE_FDATASYNC
-
 /* Define to 1 if fseeko (and presumably ftello) exists and is declared. */
 #undef HAVE_FSEEKO
 
diff --git a/src/include/port/freebsd.h b/src/include/port/freebsd.h
index 2e2e749a6b6..0e3fde55d6d 100644
--- a/src/include/port/freebsd.h
+++ b/src/include/port/freebsd.h
@@ -5,6 +5,4 @@
  * would prefer open_datasync on FreeBSD 13+, but that is not a good choice on
  * many systems.
  */
-#ifdef HAVE_FDATASYNC
 #define PLATFORM_DEFAULT_SYNC_METHOD	SYNC_METHOD_FDATASYNC
-#endif
diff --git a/src/include/port/win32_port.h b/src/include/port/win32_port.h
index 336e11b3ba4..0eaa97561a0 100644
--- a/src/include/port/win32_port.h
+++ b/src/include/port/win32_port.h
@@ -83,14 +83,6 @@
 #define HAVE_FSYNC_WRITETHROUGH
 #define FSYNC_WRITETHROUGH_IS_FSYNC
 
-/*
- * We have a replacement for fdatasync() in src/port/fdatasync.c, which is
- * unconditionally used by MSVC and Mingw builds.
- */
-#ifndef HAVE_FDATASYNC
-#define HAVE_FDATASYNC
-#endif
-
 #define USES_WINSOCK
 
 /*
diff --git a/src/port/fdatasync.c b/src/port/win32fdatasync.c
index afef853aa3c..31d631c6962 100644
--- a/src/port/fdatasync.c
+++ b/src/port/win32fdatasync.c
@@ -1,12 +1,12 @@
 /*-------------------------------------------------------------------------
  *
- * fdatasync.c
+ * win32fdatasync.c
  *	   Win32 fdatasync() replacement
  *
  *
- * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
  *
- * src/port/fdatasync.c
+ * src/port/win32fdatasync.c
  *
  *-------------------------------------------------------------------------
  */
diff --git a/src/tools/msvc/Mkvcbuild.pm b/src/tools/msvc/Mkvcbuild.pm
index a06dbcae4d2..8d88e78f051 100644
--- a/src/tools/msvc/Mkvcbuild.pm
+++ b/src/tools/msvc/Mkvcbuild.pm
@@ -99,7 +99,7 @@ sub mkvcbuild
 	$solution = CreateSolution($vsVersion, $config);
 
 	our @pgportfiles = qw(
-	  chklocale.c explicit_bzero.c fdatasync.c
+	  chklocale.c explicit_bzero.c
 	  getpeereid.c getrusage.c inet_aton.c
 	  getaddrinfo.c gettimeofday.c inet_net_ntop.c kill.c open.c
 	  snprintf.c strlcat.c strlcpy.c dirmod.c noblock.c path.c
@@ -110,6 +110,7 @@ sub mkvcbuild
 	  strerror.c tar.c
 	  win32dlopen.c
 	  win32env.c win32error.c
+	  win32fdatasync.c
 	  win32link.c
 	  win32pread.c
 	  win32pwrite.c
diff --git a/src/tools/msvc/Solution.pm b/src/tools/msvc/Solution.pm
index bd8b755b964..d7ab6ab2587 100644
--- a/src/tools/msvc/Solution.pm
+++ b/src/tools/msvc/Solution.pm
@@ -252,7 +252,6 @@ sub GenerateFiles
 		HAVE_EDITLINE_READLINE_H                    => undef,
 		HAVE_EXECINFO_H                             => undef,
 		HAVE_EXPLICIT_BZERO                         => undef,
-		HAVE_FDATASYNC                              => 1,
 		HAVE_FSEEKO                                 => 1,
 		HAVE_FUNCNAME__FUNC                         => undef,
 		HAVE_FUNCNAME__FUNCTION                     => 1,