From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0260FC4332E for ; Mon, 23 Mar 2020 19:15:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C5D53206C3 for ; Mon, 23 Mar 2020 19:15:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="icqF0/uC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727646AbgCWTPa (ORCPT ); Mon, 23 Mar 2020 15:15:30 -0400 Received: from mail-io1-f67.google.com ([209.85.166.67]:42682 "EHLO mail-io1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727218AbgCWTPa (ORCPT ); Mon, 23 Mar 2020 15:15:30 -0400 Received: by mail-io1-f67.google.com with SMTP id q128so15512461iof.9 for ; Mon, 23 Mar 2020 12:15:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=6qjt3tOTpTkCadoLmRyd0WlPaO2sndLsTPYlubINSJs=; b=icqF0/uCvcIASg7KwMtOmgkH+gWdJ2L15TICEkaS2pYA67eqRFf+PhKBT7yFpbf4ml zRRnop32ZDGPmyCNZp8Dh3Qlnu3Svm1KQ+9yPdiyMfyC7Oy6JTwr9SCnShbBKy4rXaaN NXaHMmLqd+mt/aey7e1wJUEqLutnsTYIhrMDGePopo1PWIVCy7Bsx0dVU/JEt23w7AG/ rh3XtvqGci1itB9y+gr8ELMrvkWSZ6fbHE3Ids2NoS5L+gyGEu1izgyGBMQwwl5Tq98m BLwGV+bbActsVpXf5zkcWJ/lv/ybRv/JMylw6gzRCrTBSKau4vrKXF/zk6iy/vjchtCy U64g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=6qjt3tOTpTkCadoLmRyd0WlPaO2sndLsTPYlubINSJs=; b=p25d9FiKQ95n8lQ3tz+GamnGpZwZKaKio+OMjgkp7WHAawTH5wn6nYnv4kQR3rRXoy /vn2yH8YYaSLPGWRJ79VwkhiRIituntK/NqldSRllbznfI+wRt/gfL1YlKHbOlYfy/8r 3CQxsc97MgNRCnOtpxKbu4iodcWEftGXB21bZEO/HQyuIAUPTCXDasSG+VRVk72pXSw5 sIvCZrkrUrxZPn/KdbqOW6G0+zh4WxiINAGkbK50PRnUraUX7X+F+9DBTC1+Imgyh12c wOIKL8Hd9C0A6matscBWJ8m1IQOVf1bha2Oqs+x2xz06DQX3Qqx3zNc+Pv+FIQJlWag4 9N9A== X-Gm-Message-State: ANhLgQ2cFT7wD64PWVKHGocc8oDEqJZMxgPq0u2fc7jYLelKuJe6pwl2 IYkoWQyeYwVRQBjHcQPB14kHCkB0/NfU8AerE2s= X-Google-Smtp-Source: ADFU+vsTPxnHJYF9N4DWvN6jIBPabldaHoeKoGkckvsOz/5ZJhq8xCXnol1gD6/Kw2sCZtrOeXFqRQegtxK26Mg34kM= X-Received: by 2002:a02:304a:: with SMTP id q71mr21306789jaq.123.1584990929308; Mon, 23 Mar 2020 12:15:29 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Amir Goldstein Date: Mon, 23 Mar 2020 21:15:17 +0200 Message-ID: Subject: Re: Kernel warnings in fs/inode.c:302 drop_nlink+0x28/0x40 To: Miklos Szeredi Cc: Phasip , overlayfs Content-Type: text/plain; charset="UTF-8" Sender: linux-unionfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-unionfs@vger.kernel.org On Mon, Mar 23, 2020 at 7:27 PM Amir Goldstein wrote: > > On Mon, Mar 23, 2020 at 4:53 PM Miklos Szeredi wrote: > > > > On Mon, Mar 23, 2020 at 3:21 PM Miklos Szeredi wrote: > > > > > > On Mon, Mar 23, 2020 at 2:24 PM Amir Goldstein wrote: > > > > > > IDGI. coming from vfs_unlink() and vfs_rename() it doesn't look like > > > > it is possible for victim inode not to have a hashed alias, so the > > > > alias test seems futile. > > > > > > Yeah, needs a comment: both ovl_remove_upper() and > > > ovl_remove_and_whiteout() unhash the dentry before returning, so > > > d_find_alias() will find another hashed dentry or none. > > > > Except that doesn't seem to be true for the overwriting rename case... > > > > Attached patch should work for both. > > > > It still looks quite hacky. > Why do we not look at upper->i_nlink in order to fix the situation? > > For index=on, there is already code to handle lower hardlink skew case, > including pr_warn and several xfstests (overlay/034 for example). > The check is buried in ovl_nlink_end() => ovl_cleanup_index(). > It's keeping overlay i_nlink above upper i_nlink. > > In fact, if you change one line in overlay/034 it triggers the reported > bug, so we can just fork this test. > > -lowerdir=$OVL_BASE_SCRATCH_MNT/$OVL_LOWER > +lowerdir=$OVL_BASE_SCRATCH_MNT/$OVL_UPPER > workdir=$OVL_BASE_SCRATCH_MNT/$OVL_WORK > > How about adding a check in ovl_nlink_start() to fix overlay i_nlink > below upper i_link? > It would be a valid check for both index=off and on. > I will try to write it up later. > https://lore.kernel.org/linux-unionfs/20200323190850.3091-1-amir73il@gmail.com/T/#u Sorry, Phasip, forgot to CC you. Thanks, Amir.