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.

14 files changed, 278 insertions, 179 deletions

diff --git a/cpukit/libfs/src/dosfs/fat_file.c b/cpukit/libfs/src/dosfs/fat_file.c
index a10347ccc4..73ea076819 100644
--- a/cpukit/libfs/src/dosfs/fat_file.c
+++ b/cpukit/libfs/src/dosfs/fat_file.c
@@ -774,65 +774,6 @@ fat_file_mark_removed(
     fat_fd->flags |= FAT_FILE_REMOVED;
 }
 
-/* fat_file_datasync --
- *     Synchronize fat-file -  flush all buffered data to the media.
- *
- * PARAMETERS:
- *     mt_entry - mount table entry
- *     fat_fd   - fat-file descriptor
- *
- * RETURNS:
- *     RC_OK on success, or -1 if error occured and errno set appropriately
- */
-int
-fat_file_datasync(
-    rtems_filesystem_mount_table_entry_t *mt_entry,
-    fat_file_fd_t                        *fat_fd
-    )
-{
-    int                 rc = RC_OK;
-    rtems_status_code   sc = RTEMS_SUCCESSFUL;
-    fat_fs_info_t      *fs_info = mt_entry->fs_info;
-    uint32_t            cur_cln = fat_fd->cln;
-    rtems_bdbuf_buffer *block = NULL;
-    uint32_t            sec = 0;
-    uint32_t            i = 0;
-
-    if (fat_fd->fat_file_size == 0)
-        return RC_OK;
-
-    /*
-     * we can use only one bdbuf :( and we also know that cache is useless
-     * for sync operation, so don't use it
-     */
-    rc = fat_buf_release(fs_info);
-    if (rc != RC_OK)
-        return rc;
-
-    /* for each cluster of the file ... */
-    while ((cur_cln & fs_info->vol.mask) < fs_info->vol.eoc_val)
-    {
-        sec = fat_cluster_num_to_sector_num(mt_entry, cur_cln);
-        /* for each sector in cluster ... */
-        for ( i = 0; i < fs_info->vol.spc; i++ )
-        {
-            /* ... sync it */
-            sc = rtems_bdbuf_read(fs_info->vol.dd, (sec + i), &block);
-            if (sc != RTEMS_SUCCESSFUL)
-                rtems_set_errno_and_return_minus_one( EIO );
-
-            sc = rtems_bdbuf_sync(block);
-            if ( sc != RTEMS_SUCCESSFUL )
-                rtems_set_errno_and_return_minus_one( EIO );
-        }
-
-        rc = fat_get_fat_cluster(mt_entry, cur_cln, &cur_cln);
-        if ( rc != RC_OK )
-            return rc;
-    }
-    return rc;
-}
-
 /* fat_file_size --
  *     Calculate fat-file size - fat-file is nothing that clusters chain, so
  *     go through all clusters in the chain and count it. Only
diff --git a/cpukit/libfs/src/dosfs/fat_file.h b/cpukit/libfs/src/dosfs/fat_file.h
index 30614c8f46..3a338a59ea 100644
--- a/cpukit/libfs/src/dosfs/fat_file.h
+++ b/cpukit/libfs/src/dosfs/fat_file.h
@@ -168,11 +168,6 @@ fat_file_truncate(rtems_filesystem_mount_table_entry_t *mt_entry,
                   uint32_t                              new_length);
 
 int
-fat_file_datasync(rtems_filesystem_mount_table_entry_t *mt_entry,
-                  fat_file_fd_t                        *fat_fd);
-
-
-int
 fat_file_ioctl(rtems_filesystem_mount_table_entry_t *mt_entry,
                fat_file_fd_t                        *fat_fd,
                int                                   cmd,
diff --git a/cpukit/libfs/src/dosfs/msdos.h b/cpukit/libfs/src/dosfs/msdos.h
index 0696b8f1fb..409c41897e 100644
--- a/cpukit/libfs/src/dosfs/msdos.h
+++ b/cpukit/libfs/src/dosfs/msdos.h
@@ -399,6 +399,10 @@ int msdos_get_dotdot_dir_info_cluster_num_and_offset(
     char                                 *dir_entry
 );
 
+int msdos_sync_unprotected(msdos_fs_info_t *fs_info);
+
+int msdos_sync(rtems_libio_t *iop);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/cpukit/libfs/src/dosfs/msdos_dir.c b/cpukit/libfs/src/dosfs/msdos_dir.c
index 38ea6675f7..8bd807dc1b 100644
--- a/cpukit/libfs/src/dosfs/msdos_dir.c
+++ b/cpukit/libfs/src/dosfs/msdos_dir.c
@@ -457,34 +457,3 @@ msdos_dir_stat(
  * RETURNS:
  *
  */
-
-/* msdos_dir_sync --
- *     The following routine does a syncronization on a MSDOS directory node.
- *     DIR_WrtTime, DIR_WrtDate and DIR_fileSize fields of 32 Bytes Directory
- *     Entry Structure should not be updated for directories, so only call
- *     to corresponding fat-file routine.
- *
- * PARAMETERS:
- *     iop - file control block
- *
- * RETURNS:
- *     RC_OK on success, or -1 if error occured (errno set apropriately).
- */
-int
-msdos_dir_sync(rtems_libio_t *iop)
-{
-    int                rc = RC_OK;
-    rtems_status_code  sc = RTEMS_SUCCESSFUL;
-    fat_file_fd_t     *fat_fd = iop->pathinfo.node_access;
-    msdos_fs_info_t   *fs_info = iop->pathinfo.mt_entry->fs_info;
-
-    sc = rtems_semaphore_obtain(fs_info->vol_sema, RTEMS_WAIT,
-                                MSDOS_VOLUME_SEMAPHORE_TIMEOUT);
-    if (sc != RTEMS_SUCCESSFUL)
-        rtems_set_errno_and_return_minus_one(EIO);
-
-    rc = fat_file_datasync(iop->pathinfo.mt_entry, fat_fd);
-
-    rtems_semaphore_release(fs_info->vol_sema);
-    return rc;
-}
diff --git a/cpukit/libfs/src/dosfs/msdos_file.c b/cpukit/libfs/src/dosfs/msdos_file.c
index f68e44f948..176ec8e8db 100644
--- a/cpukit/libfs/src/dosfs/msdos_file.c
+++ b/cpukit/libfs/src/dosfs/msdos_file.c
@@ -27,30 +27,11 @@
 
 #include "msdos.h"
 
-/* msdos_file_close --
- *     Close fat-file which correspondes to the file. If fat-file descriptor
- *     which correspondes to the file is not marked "removed", synchronize
- *     size, first cluster number, write time and date fields of the file.
- *
- * PARAMETERS:
- *     iop - file control block
- *
- * RETURNS:
- *     RC_OK, if file closed successfully, or -1 if error occured (errno set
- *     appropriately)
- */
-int
-msdos_file_close(rtems_libio_t *iop)
+static int
+msdos_file_update(rtems_libio_t *iop)
 {
-    int                rc = RC_OK;
-    rtems_status_code  sc = RTEMS_SUCCESSFUL;
-    msdos_fs_info_t   *fs_info = iop->pathinfo.mt_entry->fs_info;
-    fat_file_fd_t     *fat_fd = iop->pathinfo.node_access;
-
-    sc = rtems_semaphore_obtain(fs_info->vol_sema, RTEMS_WAIT,
-                                MSDOS_VOLUME_SEMAPHORE_TIMEOUT);
-    if (sc != RTEMS_SUCCESSFUL)
-        rtems_set_errno_and_return_minus_one(EIO);
+    int              rc = RC_OK;
+    fat_file_fd_t   *fat_fd = iop->pathinfo.node_access;
 
     /*
      * if fat-file descriptor is not marked as "removed", synchronize
@@ -61,25 +42,51 @@ msdos_file_close(rtems_libio_t *iop)
         rc = msdos_set_first_cluster_num(iop->pathinfo.mt_entry, fat_fd);
         if (rc != RC_OK)
         {
-            rtems_semaphore_release(fs_info->vol_sema);
             return rc;
         }
 
         rc = msdos_set_file_size(iop->pathinfo.mt_entry, fat_fd);
         if (rc != RC_OK)
         {
-            rtems_semaphore_release(fs_info->vol_sema);
             return rc;
         }
 
         rc = msdos_set_dir_wrt_time_and_date(iop->pathinfo.mt_entry, fat_fd);
         if (rc != RC_OK)
         {
-            rtems_semaphore_release(fs_info->vol_sema);
             return rc;
         }
     }
 
+    return rc;
+}
+
+/* msdos_file_close --
+ *     Close fat-file which correspondes to the file. If fat-file descriptor
+ *     which correspondes to the file is not marked "removed", synchronize
+ *     size, first cluster number, write time and date fields of the file.
+ *
+ * PARAMETERS:
+ *     iop - file control block
+ *
+ * RETURNS:
+ *     RC_OK, if file closed successfully, or -1 if error occured (errno set
+ *     appropriately)
+ */
+int
+msdos_file_close(rtems_libio_t *iop)
+{
+    int                rc = RC_OK;
+    rtems_status_code  sc = RTEMS_SUCCESSFUL;
+    msdos_fs_info_t   *fs_info = iop->pathinfo.mt_entry->fs_info;
+
+    sc = rtems_semaphore_obtain(fs_info->vol_sema, RTEMS_WAIT,
+                                MSDOS_VOLUME_SEMAPHORE_TIMEOUT);
+    if (sc != RTEMS_SUCCESSFUL)
+        rtems_set_errno_and_return_minus_one(EIO);
+
+    rc = msdos_file_update(iop);
+
     rtems_semaphore_release(fs_info->vol_sema);
     return rc;
 }
@@ -276,67 +283,14 @@ msdos_file_sync(rtems_libio_t *iop)
     if (sc != RTEMS_SUCCESSFUL)
         rtems_set_errno_and_return_minus_one(EIO);
 
-    /* synchronize file data */
-    rc = fat_file_datasync(iop->pathinfo.mt_entry, fat_fd);
+    rc = msdos_file_update(iop);
     if (rc != RC_OK)
     {
         rtems_semaphore_release(fs_info->vol_sema);
         return rc;
     }
 
-    /*
-     * if fat-file descriptor is not marked "removed" - synchronize file
-     * metadata
-     */
-    if (!FAT_FILE_IS_REMOVED(fat_fd))
-    {
-        rc = msdos_set_first_cluster_num(iop->pathinfo.mt_entry, fat_fd);
-        if (rc != RC_OK)
-        {
-            rtems_semaphore_release(fs_info->vol_sema);
-            return rc;
-        }
-        rc = msdos_set_file_size(iop->pathinfo.mt_entry, fat_fd);
-        if (rc != RC_OK)
-        {
-            rtems_semaphore_release(fs_info->vol_sema);
-            return rc;
-        }
-        rc = msdos_set_dir_wrt_time_and_date(iop->pathinfo.mt_entry, fat_fd);
-        if (rc != RC_OK)
-        {
-            rtems_semaphore_release(fs_info->vol_sema);
-            return rc;
-        }
-    }
-
-    rtems_semaphore_release(fs_info->vol_sema);
-    return RC_OK;
-}
-
-/* msdos_file_datasync --
- *     Synchronize file - synchronize only file data (metadata is letf intact).
- *
- * PARAMETERS:
- *     iop - file control block
- *
- * RETURNS:
- *     RC_OK on success, or -1 if error occured (errno set appropriately)
- */
-int
-msdos_file_datasync(rtems_libio_t *iop)
-{
-    rtems_status_code  sc = RTEMS_SUCCESSFUL;
-    fat_file_fd_t     *fat_fd = iop->pathinfo.node_access;
-    msdos_fs_info_t   *fs_info = iop->pathinfo.mt_entry->fs_info;
-
-    sc = rtems_semaphore_obtain(fs_info->vol_sema, RTEMS_WAIT,
-                                MSDOS_VOLUME_SEMAPHORE_TIMEOUT);
-    if (sc != RTEMS_SUCCESSFUL)
-        rtems_set_errno_and_return_minus_one(EIO);
-
-    /* synchronize file data */
-    fat_file_datasync(iop->pathinfo.mt_entry, fat_fd);
+    rc = msdos_sync_unprotected(fs_info);
 
     rtems_semaphore_release(fs_info->vol_sema);
     return RC_OK;
diff --git a/cpukit/libfs/src/dosfs/msdos_handlers_dir.c b/cpukit/libfs/src/dosfs/msdos_handlers_dir.c
index 8c7dcdc0a5..7da9c1ec77 100644
--- a/cpukit/libfs/src/dosfs/msdos_handlers_dir.c
+++ b/cpukit/libfs/src/dosfs/msdos_handlers_dir.c
@@ -27,7 +27,7 @@ const rtems_filesystem_file_handlers_r msdos_dir_handlers = {
     rtems_filesystem_default_lseek_directory,
     msdos_dir_stat,
     rtems_filesystem_default_ftruncate_directory,
-    msdos_dir_sync,
-    msdos_dir_sync,
+    msdos_sync,
+    msdos_sync,
     rtems_filesystem_default_fcntl
 };
diff --git a/cpukit/libfs/src/dosfs/msdos_handlers_file.c b/cpukit/libfs/src/dosfs/msdos_handlers_file.c
index 12cdaa048e..e4494f884e 100644
--- a/cpukit/libfs/src/dosfs/msdos_handlers_file.c
+++ b/cpukit/libfs/src/dosfs/msdos_handlers_file.c
@@ -28,6 +28,6 @@ const rtems_filesystem_file_handlers_r msdos_file_handlers = {
     msdos_file_stat,
     msdos_file_ftruncate,
     msdos_file_sync,
-    msdos_file_datasync,
+    msdos_sync,
     rtems_filesystem_default_fcntl
 };
diff --git a/cpukit/libfs/src/dosfs/msdos_misc.c b/cpukit/libfs/src/dosfs/msdos_misc.c
index d11bd83f52..511ac44dda 100644
--- a/cpukit/libfs/src/dosfs/msdos_misc.c
+++ b/cpukit/libfs/src/dosfs/msdos_misc.c
@@ -1646,3 +1646,34 @@ int msdos_find_node_by_cluster_num_in_fat_file(
     }
     return MSDOS_NAME_NOT_FOUND_ERR;
 }
+
+int
+msdos_sync_unprotected(msdos_fs_info_t *fs_info)
+{
+    int rc = fat_buf_release(&fs_info->fat);
+    rtems_status_code sc = rtems_bdbuf_syncdev(fs_info->fat.vol.dd);
+    if (sc != RTEMS_SUCCESSFUL) {
+	errno = EIO;
+	rc = -1;
+    }
+
+    return rc;
+}
+
+int
+msdos_sync(rtems_libio_t *iop)
+{
+    int                rc = RC_OK;
+    rtems_status_code  sc = RTEMS_SUCCESSFUL;
+    msdos_fs_info_t   *fs_info = iop->pathinfo.mt_entry->fs_info;
+
+    sc = rtems_semaphore_obtain(fs_info->vol_sema, RTEMS_WAIT,
+                                MSDOS_VOLUME_SEMAPHORE_TIMEOUT);
+    if (sc != RTEMS_SUCCESSFUL)
+        rtems_set_errno_and_return_minus_one(EIO);
+
+    rc = msdos_sync_unprotected(fs_info);
+
+    rtems_semaphore_release(fs_info->vol_sema);
+    return rc;
+}
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>