dosfs: Remove fat_file_datasync()

The fat_file_datasync() read every cluster of the file into the cache
and then synchronized it step-by-step.  For unmodified buffers this is a
non-operation.  For modified buffers this will wake-up the swapout task
which performs then a single buffer write operation.  This is usually
quite inefficient.  Firstly we do single buffer writes, secondly we
may perform a lot of unnecessary read operations (for huge files this is
really bad), and thirdly this leads likely to cache evictions.

The synchronization procedure is replaced by a simple
rtems_bdbuf_sync_dev().  This has the side-effect that also buffers not
related to the file are synchronized, but since the modified list is
normally short this should be acceptable.

6 files changed, 205 insertions, 0 deletions

diff --git a/testsuites/fstests/Makefile.am b/testsuites/fstests/Makefile.am
index f765a89af4..43832760a0 100644
--- a/testsuites/fstests/Makefile.am
+++ b/testsuites/fstests/Makefile.am
@@ -5,6 +5,7 @@
 ACLOCAL_AMFLAGS = -I ../aclocal
 
 SUBDIRS = 
+SUBDIRS += fsdosfssync01
 SUBDIRS += imfs_fserror
 SUBDIRS += imfs_fslink
 SUBDIRS += imfs_fspatheval
diff --git a/testsuites/fstests/configure.ac b/testsuites/fstests/configure.ac
index 833a85c21a..ccf9ee0bcf 100644
--- a/testsuites/fstests/configure.ac
+++ b/testsuites/fstests/configure.ac
@@ -79,6 +79,7 @@ AC_CHECK_SIZEOF([blkcnt_t])
 
 # Explicitly list all Makefiles here
 AC_CONFIG_FILES([Makefile
+fsdosfssync01/Makefile
 imfs_fserror/Makefile
 imfs_fslink/Makefile
 imfs_fspatheval/Makefile
diff --git a/testsuites/fstests/fsdosfssync01/Makefile.am b/testsuites/fstests/fsdosfssync01/Makefile.am
new file mode 100644
index 0000000000..eb557f11e2
--- /dev/null
+++ b/testsuites/fstests/fsdosfssync01/Makefile.am
@@ -0,0 +1,19 @@
+rtems_tests_PROGRAMS = fsdosfssync01
+fsdosfssync01_SOURCES = init.c
+
+dist_rtems_tests_DATA = fsdosfssync01.scn fsdosfssync01.doc
+
+include $(RTEMS_ROOT)/make/custom/@RTEMS_BSP@.cfg
+include $(top_srcdir)/../automake/compile.am
+include $(top_srcdir)/../automake/leaf.am
+
+AM_CPPFLAGS += -I$(top_srcdir)/../support/include
+
+LINK_OBJS = $(fsdosfssync01_OBJECTS)
+LINK_LIBS = $(fsdosfssync01_LDLIBS)
+
+fsdosfssync01$(EXEEXT): $(fsdosfssync01_OBJECTS) $(fsdosfssync01_DEPENDENCIES)
+	@rm -f fsdosfssync01$(EXEEXT)
+	$(make-exe)
+
+include $(top_srcdir)/../automake/local.am
diff --git a/testsuites/fstests/fsdosfssync01/fsdosfssync01.doc b/testsuites/fstests/fsdosfssync01/fsdosfssync01.doc
new file mode 100644
index 0000000000..98b558a4f5
--- /dev/null
+++ b/testsuites/fstests/fsdosfssync01/fsdosfssync01.doc
@@ -0,0 +1,11 @@
+This file describes the directives and concepts tested by this test set.
+
+test set name: fsdosfssync01
+
+directives:
+
+  TBD
+
+concepts:
+
+  TBD
diff --git a/testsuites/fstests/fsdosfssync01/fsdosfssync01.scn b/testsuites/fstests/fsdosfssync01/fsdosfssync01.scn
new file mode 100644
index 0000000000..c181dbf72c
--- /dev/null
+++ b/testsuites/fstests/fsdosfssync01/fsdosfssync01.scn
@@ -0,0 +1,2 @@
+*** TEST FSDOSFSSYNC 1 ***
+*** END OF TEST FSDOSFSSYNC 1 ***
diff --git a/testsuites/fstests/fsdosfssync01/init.c b/testsuites/fstests/fsdosfssync01/init.c
new file mode 100644
index 0000000000..72481b29b8
--- /dev/null
+++ b/testsuites/fstests/fsdosfssync01/init.c
@@ -0,0 +1,171 @@
+/*
+ * Copyright (c) 2012 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Obere Lagerstr. 30
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.com/license/LICENSE.
+ */
+
+#ifdef HAVE_CONFIG_H
+  #include "config.h"
+#endif
+
+#include "tmacros.h"
+
+#include <sys/stat.h>
+#include <errno.h>
+#include <string.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include <rtems/libio.h>
+#include <rtems/blkdev.h>
+#include <rtems/dosfs.h>
+#include <rtems/ramdisk.h>
+
+static void create_file(const char *file)
+{
+  int fd;
+  int rv;
+
+  fd = creat(file, S_IRWXU | S_IRWXG | S_IRWXO);
+  rtems_test_assert(fd >= 0);
+
+  rv = fsync(fd);
+  rtems_test_assert(rv == 0);
+
+  rv = close(fd);
+  rtems_test_assert(rv == 0);
+}
+
+static void write_to_file(const char *file, bool sync)
+{
+  int fd;
+  char buf [1];
+  ssize_t n;
+  off_t pos;
+  int rv;
+
+  fd = open(file, O_RDWR);
+  rtems_test_assert(fd >= 0);
+
+  n = write(fd, buf, sizeof(buf));
+  rtems_test_assert(n == (ssize_t) sizeof(buf));
+
+  pos = lseek(fd, 0, SEEK_END);
+  rtems_test_assert(pos == sizeof(buf));
+
+  if (sync) {
+    rv = fsync(fd);
+    rtems_test_assert(rv == 0);
+  }
+
+  rv = close(fd);
+  rtems_test_assert(rv == 0);
+}
+
+static void check_file_size(const char *file, off_t size)
+{
+  int fd;
+  off_t pos;
+  int rv;
+
+  fd = open(file, O_RDWR);
+  rtems_test_assert(fd >= 0);
+
+  pos = lseek(fd, 0, SEEK_END);
+  rtems_test_assert(pos == size);
+
+  rv = close(fd);
+  rtems_test_assert(rv == 0);
+}
+
+static void test(const char *rda, const char *mnt, const char *file)
+{
+  rtems_status_code sc;
+  int disk_fd;
+  int rv;
+
+  sc = rtems_disk_io_initialize();
+  rtems_test_assert(sc == RTEMS_SUCCESSFUL);
+
+  disk_fd = open(rda, O_RDWR);
+  rtems_test_assert(disk_fd >= 0);
+
+  rv = msdos_format(rda, NULL);
+  rtems_test_assert(rv == 0);
+
+  rv = mount_and_make_target_path(
+    rda,
+    mnt,
+    RTEMS_FILESYSTEM_TYPE_DOSFS,
+    RTEMS_FILESYSTEM_READ_WRITE,
+    NULL
+  );
+  rtems_test_assert(rv == 0);
+
+  create_file(file);
+  rv = rtems_disk_fd_purge(disk_fd);
+  rtems_test_assert(rv == 0);
+
+  write_to_file(file, false);
+  rv = rtems_disk_fd_purge(disk_fd);
+  rtems_test_assert(rv == 0);
+  check_file_size(file, 0);
+
+  write_to_file(file, true);
+  rv = rtems_disk_fd_purge(disk_fd);
+  rtems_test_assert(rv == 0);
+  check_file_size(file, 1);
+
+  rv = unmount(mnt);
+  rtems_test_assert(rv == 0);
+
+  rv = close(disk_fd);
+  rtems_test_assert(rv == 0);
+}
+
+static void Init(rtems_task_argument arg)
+{
+  puts("\n\n*** TEST FSDOSFSSYNC 1 ***");
+
+  test("/dev/rda", "/mnt", "/mnt/file");
+
+  puts("*** END OF TEST FSDOSFSSYNC 1 ***");
+
+  rtems_test_exit(0);
+}
+
+rtems_ramdisk_config rtems_ramdisk_configuration [] = {
+  { .block_size = 512, .block_num = 1024 }
+};
+
+size_t rtems_ramdisk_configuration_size = 1;
+
+#define CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER
+#define CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER
+#define CONFIGURE_APPLICATION_EXTRA_DRIVERS RAMDISK_DRIVER_TABLE_ENTRY
+#define CONFIGURE_APPLICATION_NEEDS_LIBBLOCK
+
+#define CONFIGURE_LIBIO_MAXIMUM_FILE_DESCRIPTORS 6
+
+#define CONFIGURE_USE_IMFS_AS_BASE_FILESYSTEM
+
+#define CONFIGURE_FILESYSTEM_DOSFS
+
+#define CONFIGURE_MAXIMUM_TASKS 2
+
+#define CONFIGURE_EXTRA_TASK_STACKS (8 * 1024)
+
+#define CONFIGURE_RTEMS_INIT_TASKS_TABLE
+
+#define CONFIGURE_INIT
+
+#include <rtems/confdefs.h>