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.

8 files changed, 73 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;
+}