exofs: Avoid using file_fsync()

The use of file_fsync() in exofs_file_sync() is not necessary since it
does some extra stuff not used by exofs. Open code just the parts that
are currently needed.

TODO: Farther optimization can be done to sync the sb only on inode
update of new files, Usually the sb update is not needed in exofs.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
diff --git a/fs/exofs/exofs.h b/fs/exofs/exofs.h
index c413b74..5ec72e0 100644
--- a/fs/exofs/exofs.h
+++ b/fs/exofs/exofs.h
@@ -154,6 +154,9 @@
 int exofs_set_link(struct inode *, struct exofs_dir_entry *, struct page *,
 		    struct inode *);
 
+/* super.c               */
+int exofs_sync_fs(struct super_block *sb, int wait);
+
 /*********************
  * operation vectors *
  *********************/