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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 C70CDC433E0 for ; Wed, 27 May 2020 19:49:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 92D0A20890 for ; Wed, 27 May 2020 19:49:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="LlVy+jVz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728115AbgE0Ttc (ORCPT ); Wed, 27 May 2020 15:49:32 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:36795 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726114AbgE0Ttb (ORCPT ); Wed, 27 May 2020 15:49:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1590608969; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=4/jJDAC3mkkPrzSCt25HqCWPfSxbyQweSaAiyOJWMCI=; b=LlVy+jVzhGKrNVpXo8wNPYdiRpPxoaNqkb8DmwbrsPKTyZrNtRhykJcNBoNWZvi4GI7v9K G7P1cFWUN46fEm6uXIADm/Dk0uGWaQ/HLdk4wiIMwiFVOc56qtcFeHOUL5UrVwnyFjRiOa kvihbcaPZ2AEHUgqW/1PbXj+6gSCzJk= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-491-zVAbjP5nPde-dbId330wfg-1; Wed, 27 May 2020 15:49:27 -0400 X-MC-Unique: zVAbjP5nPde-dbId330wfg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A4E1C108BD0A; Wed, 27 May 2020 19:49:26 +0000 (UTC) Received: from horse.redhat.com (ovpn-116-83.rdu2.redhat.com [10.10.116.83]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1F6D760E1C; Wed, 27 May 2020 19:49:26 +0000 (UTC) Received: by horse.redhat.com (Postfix, from userid 10451) id A3A1D220391; Wed, 27 May 2020 15:49:25 -0400 (EDT) Date: Wed, 27 May 2020 15:49:25 -0400 From: Vivek Goyal To: Amir Goldstein Cc: yangerkun , Miklos Szeredi , overlayfs Subject: Re: [PATCH] ovl: fix some bug exist in ovl_get_inode Message-ID: <20200527194925.GD140950@redhat.com> References: <20200527041711.60219-1-yangerkun@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Sender: linux-unionfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-unionfs@vger.kernel.org On Wed, May 27, 2020 at 02:16:00PM +0300, Amir Goldstein wrote: > On Wed, May 27, 2020 at 6:45 AM yangerkun wrote: > > > > Run generic/461 with ext4 upper/lower layer sometimes may trigger the > > bug as below(linux 4.19): > > > > [ 551.001349] overlayfs: failed to get metacopy (-5) > > [ 551.003464] overlayfs: failed to get inode (-5) > > [ 551.004243] overlayfs: cleanup of 'd44/fd51' failed (-5) > > [ 551.004941] overlayfs: failed to get origin (-5) > > [ 551.005199] ------------[ cut here ]------------ > > [ 551.006697] WARNING: CPU: 3 PID: 24674 at fs/inode.c:1528 iput+0x33b/0x400 > > ... > > [ 551.027219] Call Trace: > > [ 551.027623] ovl_create_object+0x13f/0x170 > > [ 551.028268] ovl_create+0x27/0x30 > > [ 551.028799] path_openat+0x1a35/0x1ea0 > > [ 551.029377] do_filp_open+0xad/0x160 > > [ 551.029944] ? vfs_writev+0xe9/0x170 > > [ 551.030499] ? page_counter_try_charge+0x77/0x120 > > [ 551.031245] ? __alloc_fd+0x160/0x2a0 > > [ 551.031832] ? do_sys_open+0x189/0x340 > > [ 551.032417] ? get_unused_fd_flags+0x34/0x40 > > [ 551.033081] do_sys_open+0x189/0x340 > > [ 551.033632] __x64_sys_creat+0x24/0x30 > > [ 551.034219] do_syscall_64+0xd5/0x430 > > [ 551.034800] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > ... > > [ 556.107515] BUG: Dentry 000000006bc1d73f{i=4129c,n=fd51} still in use (-1) [unmount of ext4 sdb] > > [ 556.108946] ------------[ cut here ]------------ > > [ 556.109686] WARNING: CPU: 1 PID: 24682 at fs/dcache.c:1557 umount_check+0x95/0xc0 > > [ 556.130343] d_walk+0x10d/0x430 > > [ 556.130832] do_one_tree+0x30/0x60 > > [ 556.131365] shrink_dcache_for_umount+0x38/0xe0 > > [ 556.132063] generic_shutdown_super+0x2e/0x1c0 > > [ 556.132747] kill_block_super+0x29/0x80 > > [ 556.133338] deactivate_locked_super+0x7a/0x100 > > [ 556.134034] deactivate_super+0x9d/0xb0 > > [ 556.134627] cleanup_mnt+0x67/0x100 > > [ 556.135173] __cleanup_mnt+0x16/0x20 > > [ 556.135731] task_work_run+0xdb/0x110 > > [ 556.136306] exit_to_usermode_loop+0x197/0x1b0 > > [ 556.136991] do_syscall_64+0x3ce/0x430 > > [ 556.137571] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > ... > > [ 556.378140] VFS: Busy inodes after unmount of sdb. Self-destruct in 5 seconds. Have a nice day... > > > > After check the code, there may some bug need to fix: > > 1. We need to call iput once ovl_check_metacopy_xattr fail. > > 2. We need to call unlock_new_inode or the above iput(also with iput in > > ovl_create_object) will trigger the a WARN_ON since the I_NEW still > > exists. > > 3. We should move the init for upperdentry to the place below > > ovl_check_metacopy_xattr. Or the dentry reference will decrease to > > -1(error path in ovl_create_upper will inc, ovl_destroy_inode too). > > > > OR we don't check metacopy xattr in ovl_get_inode(). > > In ovl_lookup() we already checked metacopy xattr. > No reason to check it again in this subtle context. > > In ovl_lookup() can store value of upper metacopy and after we get > the inode, set the OVL_UPPERDATA inode flag according to > upperdentry && !uppermetacopy. > > That would be consistent with ovl_obtain_alias() which sets the > OVL_UPPERDATA inode flag after getting the inode. Hi Amir, This patch implements what you are suggesting. Compile tested only. Does this look ok? May be I don't need to split it up in lmetacopy and umetacopy. Ideally, lookup in lower layers should stop if an upper regular file is not metacopy. IOW, (upperdentry && !metacopy) might be sufficient check. Will look closely if this patch looks fine. Thanks Vivek --- fs/overlayfs/inode.c | 11 +---------- fs/overlayfs/namei.c | 12 +++++++----- 2 files changed, 8 insertions(+), 15 deletions(-) Index: redhat-linux/fs/overlayfs/namei.c =================================================================== --- redhat-linux.orig/fs/overlayfs/namei.c 2020-04-13 13:52:53.438294244 -0400 +++ redhat-linux/fs/overlayfs/namei.c 2020-05-27 15:28:38.242809626 -0400 @@ -823,7 +823,7 @@ struct dentry *ovl_lookup(struct inode * struct dentry *this; unsigned int i; int err; - bool metacopy = false; + bool lmetacopy = false, umetacopy=false; struct ovl_lookup_data d = { .sb = dentry->d_sb, .name = dentry->d_name, @@ -869,7 +869,7 @@ struct dentry *ovl_lookup(struct inode * goto out_put_upper; if (d.metacopy) - metacopy = true; + umetacopy = true; } if (d.redirect) { @@ -941,7 +941,7 @@ struct dentry *ovl_lookup(struct inode * } if (d.metacopy) - metacopy = true; + lmetacopy = true; /* * Do not store intermediate metacopy dentries in chain, * except top most lower metacopy dentry @@ -982,7 +982,7 @@ struct dentry *ovl_lookup(struct inode * } } - if (metacopy) { + if (lmetacopy || umetacopy) { /* * Found a metacopy dentry but did not find corresponding * data dentry @@ -1023,7 +1023,7 @@ struct dentry *ovl_lookup(struct inode * * * Always lookup index of non-dir non-metacopy and non-upper. */ - if (ctr && (!upperdentry || (!d.is_dir && !metacopy))) + if (ctr && (!upperdentry || (!d.is_dir && !(lmetacopy || umetacopy)))) origin = stack[0].dentry; if (origin && ovl_indexdir(dentry->d_sb) && @@ -1074,6 +1074,8 @@ struct dentry *ovl_lookup(struct inode * err = PTR_ERR(inode); if (IS_ERR(inode)) goto out_free_oe; + if (upperdentry && !umetacopy) + ovl_set_flag(OVL_UPPERDATA, inode); } ovl_dentry_update_reval(dentry, upperdentry, Index: redhat-linux/fs/overlayfs/inode.c =================================================================== --- redhat-linux.orig/fs/overlayfs/inode.c 2020-04-22 11:32:28.237700957 -0400 +++ redhat-linux/fs/overlayfs/inode.c 2020-05-27 15:30:21.059809626 -0400 @@ -939,7 +939,7 @@ struct inode *ovl_get_inode(struct super bool bylower = ovl_hash_bylower(sb, upperdentry, lowerdentry, oip->index); int fsid = bylower ? lowerpath->layer->fsid : 0; - bool is_dir, metacopy = false; + bool is_dir; unsigned long ino = 0; int err = oip->newinode ? -EEXIST : -ENOMEM; @@ -1000,15 +1000,6 @@ struct inode *ovl_get_inode(struct super if (oip->index) ovl_set_flag(OVL_INDEX, inode); - if (upperdentry) { - err = ovl_check_metacopy_xattr(upperdentry); - if (err < 0) - goto out_err; - metacopy = err; - if (!metacopy) - ovl_set_flag(OVL_UPPERDATA, inode); - } - OVL_I(inode)->redirect = oip->redirect; if (bylower)