lift file_*_write out of do_splice_direct()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/read_write.c

@@ -1129,7 +1129,9 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
 	if (in.file->f_flags & O_NONBLOCK)
 		fl = SPLICE_F_NONBLOCK;
 #endif
+	file_start_write(out.file);
 	retval = do_splice_direct(in.file, &pos, out.file, &out_pos, count, fl);
+	file_end_write(out.file);
 
 	if (retval > 0) {
 		add_rchar(current, retval);