From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-fsdevel-owner@vger.kernel.org>
Received: from TYO201.gate.nec.co.jp ([210.143.35.51]:42895 "EHLO
	tyo201.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1753255AbcC2Agm convert rfc822-to-8bit (ORCPT
	<rfc822;linux-fsdevel@vger.kernel.org>);
	Mon, 28 Mar 2016 20:36:42 -0400
From: Junichi Nomura <j-nomura@ce.jp.nec.com>
To: Al Viro <viro@zeniv.linux.org.uk>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>
Subject: [regression 4.6-rc1] autofs lookup fails with -ENOENT
Date: Tue, 29 Mar 2016 00:35:11 +0000
Message-ID: <56F9CDBF.7060306@ce.jp.nec.com>
Content-Language: ja-JP
Content-Type: text/plain; charset="iso-2022-jp"
Content-ID: <D8BF40E2369BF946AD04E15DC811C7B3@gisp.nec.co.jp>
Content-Transfer-Encoding: 8BIT
MIME-Version: 1.0
Sender: linux-fsdevel-owner@vger.kernel.org
List-ID: <linux-fsdevel.vger.kernel.org>

Lookup of autofs files starts failing with -ENOENT on 4.6-rc1.

git-bisect tells commit e3c13928086f1 "namei: massage lookup_slow() to
be usable by lookup_one_len_unlocked()" as the first bad commit.

With the change, walk_component() does this:

    path.dentry = lookup_slow(&nd->last, nd->path.dentry,
                                          nd->flags);
    if (IS_ERR(path.dentry))
            return PTR_ERR(path.dentry);
    if (unlikely(d_is_negative(path.dentry))) {
            dput(path.dentry);
            return -ENOENT;
    }
    path.mnt = nd->path.mnt;
    err = follow_managed(&path, nd);
    if (unlikely(err < 0))
            return err;

It returns -ENOENT before handling automount in follow_managed().
Shouldn't it call follow_managed() before checking d_is_negative()?

--
Jun'ichi Nomura, NEC Corporation