diff --git a/configure.ac b/configure.ac
index 6fd16bd36..51be1ff7b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -992,7 +992,7 @@ AC_MSG_RESULT(unsigned $glib_size_type)
 # Check for some functions
 AC_CHECK_FUNCS(lstat strerror strsignal memmove vsnprintf stpcpy strcasecmp strncasecmp poll getcwd vasprintf setenv unsetenv getc_unlocked readlink symlink fdwalk memmem)
 AC_CHECK_FUNCS(chown lchmod lchown fchmod fchown link utimes getgrgid getpwuid getresuid)
-AC_CHECK_FUNCS(getmntent_r setmntent endmntent hasmntopt getfsstat getvfsstat)
+AC_CHECK_FUNCS(getmntent_r setmntent endmntent hasmntopt getfsstat getvfsstat posix_fallocate)
 # Check for high-resolution sleep functions
 AC_CHECK_FUNCS(splice)
 AC_CHECK_FUNCS(prlimit)
diff --git a/glib/gfileutils.c b/glib/gfileutils.c
index 3c1b135ef..235064391 100644
--- a/glib/gfileutils.c
+++ b/glib/gfileutils.c
@@ -1059,6 +1059,13 @@ write_to_temp_file (const gchar  *contents,
   if (length > 0)
     {
       gsize n_written;
+
+#ifdef HAVE_POSIX_FALLOCATE
+      /* We do this on a 'best effort' basis... It may not be supported
+       * on the underlying filesystem.
+       */
+      (void) posix_fallocate (fd, 0, length);
+#endif
       
       errno = 0;