ntfs: Use new syncing helpers and update comments

Use new syncing helpers in .write and .aio_write functions. Also
remove superfluous syncing in ntfs_file_buffered_write() and update
comments about generic_osync_inode().

CC: Anton Altaparmakov <aia21@cantab.net>
CC: linux-ntfs-dev@lists.sourceforge.net
Signed-off-by: Jan Kara <jack@suse.cz>
diff --git a/fs/ntfs/file.c b/fs/ntfs/file.c
index 3140a44..4350d49 100644
--- a/fs/ntfs/file.c
+++ b/fs/ntfs/file.c
@@ -2076,14 +2076,6 @@
 	*ppos = pos;
 	if (cached_page)
 		page_cache_release(cached_page);
-	/* For now, when the user asks for O_SYNC, we actually give O_DSYNC. */
-	if (likely(!status)) {
-		if (unlikely((file->f_flags & O_SYNC) || IS_SYNC(vi))) {
-			if (!mapping->a_ops->writepage || !is_sync_kiocb(iocb))
-				status = generic_osync_inode(vi, mapping,
-						OSYNC_METADATA|OSYNC_DATA);
-		}
-  	}
 	pagevec_lru_add_file(&lru_pvec);
 	ntfs_debug("Done.  Returning %s (written 0x%lx, status %li).",
 			written ? "written" : "status", (unsigned long)written,
@@ -2145,8 +2137,8 @@
 	mutex_lock(&inode->i_mutex);
 	ret = ntfs_file_aio_write_nolock(iocb, iov, nr_segs, &iocb->ki_pos);
 	mutex_unlock(&inode->i_mutex);
-	if (ret > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
-		int err = sync_page_range(inode, mapping, pos, ret);
+	if (ret > 0) {
+		int err = generic_write_sync(file, pos, ret);
 		if (err < 0)
 			ret = err;
 	}
@@ -2173,8 +2165,8 @@
 	if (ret == -EIOCBQUEUED)
 		ret = wait_on_sync_kiocb(&kiocb);
 	mutex_unlock(&inode->i_mutex);
-	if (ret > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
-		int err = sync_page_range(inode, mapping, *ppos - ret, ret);
+	if (ret > 0) {
+		int err = generic_write_sync(file, *ppos - ret, ret);
 		if (err < 0)
 			ret = err;
 	}