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=-2.7 required=3.0 tests=BAYES_00,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 2A413C4361B for ; Thu, 17 Dec 2020 20:26:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E5DCA239FE for ; Thu, 17 Dec 2020 20:26:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731461AbgLQU0B (ORCPT ); Thu, 17 Dec 2020 15:26:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34966 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731439AbgLQU0B (ORCPT ); Thu, 17 Dec 2020 15:26:01 -0500 Received: from mail-io1-xd29.google.com (mail-io1-xd29.google.com [IPv6:2607:f8b0:4864:20::d29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CB23EC0617B0 for ; Thu, 17 Dec 2020 12:25:20 -0800 (PST) Received: by mail-io1-xd29.google.com with SMTP id m23so14034545ioy.2 for ; Thu, 17 Dec 2020 12:25:20 -0800 (PST) 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=9InF5AX9RnmhRuG6A7VtjhBT7FM4uZS/FjiBjJOFlgA=; b=NEGfcUAUh8Q3n3smS6RWVO8bobwTIBMIqTLvZxoxK6+Wv00u7d/BxqWlS6do7eK7jV llLZX0/+JVlM0d4Ft3PSaPd2KWmMBzhwQHJfmOYRVI998lV5Hk5K1gFAdBYK7Sc4Mqu+ 552VWYzOmdmXZGaazAQ1RJ+Fl3VlXJ7sXi8hbJW1xc+NnlluQVU7zhrEFPSm5YPs+hUP bvZXsRvR/KC3GQ3MRKqJOjtZKHnYMpMPbJi0u8JUH7U7afl9c73xoA3dL0oPVHUSzd9V FsOsUlNdhCAImnKc2Qi0YcS55p/P+7CAWI6tsoIEWiOvE9scK1aI3geULPF5O8/64y3P 9ZOA== 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=9InF5AX9RnmhRuG6A7VtjhBT7FM4uZS/FjiBjJOFlgA=; b=ldVR69MYM3Nb5Qn/6eT550FHPzkTXUScJUxqjQnu0DV6QNmesZMV7n8JXiRpMx2oh+ Ajy0BI4QWZar/H+VQSAey3gXsmQUD5CHcblWWIoNBFSIsNSKVkYwccvvsOkm7XTVTTPT Qkm/4fmNmC/HakJ4MjSVhlv3dgc+8QUjgg/DOqcL27nies/iF5yJ2bRytfEIRBJH4NxO YYCHEOQmOtCYmYNGEfd6CAEDJcUBQcdRayfu0MdxS39SdPpzHQU24FD2WW5ztodP5KXK cypWknaj6+1aGgvIl1rE/vpUkMM6fQTzbNJUVLhU/JgckYHT3Vbos40rU6icqNaDdB6/ 5MFQ== X-Gm-Message-State: AOAM532IWChB1GULFkBPNygCz2A/zwsv9FULidOqadzRy2zv4LYmy68g CPOdX2Qj6+kSzNQzuwlg6fbVTxZFSXpU0v6py0Y= X-Google-Smtp-Source: ABdhPJzcR8udmQcCnFEav1XCykIMCIMWPUzCMMMBcTW5fbh1Q83Upe/h1ydePEBc4omFWoKCUAf+WPbfKqNA8P5DBqc= X-Received: by 2002:a02:9f19:: with SMTP id z25mr641147jal.30.1608236720147; Thu, 17 Dec 2020 12:25:20 -0800 (PST) MIME-Version: 1.0 References: <2nv9d47zt7.fsf@aldarion.sourceruckus.org> <2n1rfrf5l0.fsf@aldarion.sourceruckus.org> In-Reply-To: From: Amir Goldstein Date: Thu, 17 Dec 2020 22:25:08 +0200 Message-ID: Subject: Re: failed open: No data available To: Michael Labriola Cc: overlayfs , Miklos Szeredi Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-unionfs@vger.kernel.org On Thu, Dec 17, 2020 at 9:46 PM Michael Labriola wrote: > > On Thu, Dec 17, 2020 at 1:07 PM Amir Goldstein wrote: > > > > On Thu, Dec 17, 2020 at 6:22 PM Michael Labriola > *snip* > > > On Thu, Dec 17, 2020 at 7:00 AM Amir Goldstein wrote: > > > Thanks, Amir. I didn't have CONFIG_DYNAMIC_DEBUG enabled, so > > > > I honestly don't expect to find much in the existing overlay debug prints > > but you never know.. > > I suspect you will have to add debug prints to find the problem. > > Ok, here goes. I had to setup a new virtual machine that doesn't use > overlayfs for its root filesystem because turning on dynamic debug > gave way too much output for a nice controlled test. It's exhibiting > the same behavior as my previous tests (5.8 good, 5.9 bad). The is > with a freshly compiled 5.9.15 w/ CONFIG_OVERLAY_FS_XINO_AUTO turned > off and CONFIG_DYNAMIC_DEBUG turned on. Here's what we get: > > echo "file fs/overlayfs/* +p" > /sys/kernel/debug/dynamic_debug/control > mount borky2.sqsh t > mount -t tmpfs tmp tt > mkdir -p tt/upper/{upper,work} > mount -t overlay -o \ > lowerdir=t,upperdir=tt/upper/upper,workdir=tt/upper/work blarg ttt > [ 164.505193] overlayfs: mkdir(work/work, 040000) = 0 > [ 164.505204] overlayfs: tmpfile(work/work, 0100000) = 0 > [ 164.505209] overlayfs: create(work/#3, 0100000) = 0 > [ 164.505210] overlayfs: rename(work/#3, work/#4, 0x4) > [ 164.505216] overlayfs: unlink(work/#3) = 0 > [ 164.505217] overlayfs: unlink(work/#4) = 0 > [ 164.505221] overlayfs: setxattr(work/work, > "trusted.overlay.opaque", "0", 1, 0x0) = 0 > > touch ttt/FOO > touch: cannot touch 'ttt/FOO': No data available > [ 191.919498] overlayfs: setxattr(upper/upper, > "trusted.overlay.impure", "y", 1, 0x0) = 0 > [ 191.919523] overlayfs: tmpfile(work/work, 0100644) = 0 > [ 191.919788] overlayfs: tmpfile(work/work, 0100644) = 0 > > That give you any hints? I'll start reading through the overlayfs > code. I've never actually looked at it, so I'll be planting printk > calls at random. ;-) We have seen that open("FOO", O_WRONLY) fails We know that FOO is lower at that time so that brings us to ovl_open ovl_maybe_copy_up ovl_copy_up_flags ovl_copy_up_one ovl_do_copy_up ovl_set_impure [ 191.919498] overlayfs: setxattr(upper/upper, "trusted.overlay.impure", "y", 1, 0x0) = 0 ovl_copy_up_tmpfile ovl_do_tmpfile [ 191.919523] overlayfs: tmpfile(work/work, 0100644) = 0 ovl_copy_up_inode This must be were we fail and likely in: ovl_copy_xattr vfs_getxattr which can return -ENODATA, but it is not expected because the xattrs returned by vfs_listxattr should exist... So first guess would be to add a debug print for xattr 'name' and return value of vfs_getxattr(). Good luck! Thanks, Amir.