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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 8C58FC00307 for ; Fri, 6 Sep 2019 14:48:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 652FE206A5 for ; Fri, 6 Sep 2019 14:48:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394586AbfIFOsi (ORCPT ); Fri, 6 Sep 2019 10:48:38 -0400 Received: from fieldses.org ([173.255.197.46]:57420 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730799AbfIFOsi (ORCPT ); Fri, 6 Sep 2019 10:48:38 -0400 Received: by fieldses.org (Postfix, from userid 2815) id C0C951C9D; Fri, 6 Sep 2019 10:48:37 -0400 (EDT) Date: Fri, 6 Sep 2019 10:48:37 -0400 From: "J. Bruce Fields" To: Jason L Tibbitts III Cc: Wolfgang Walter , linux-nfs@vger.kernel.org, km@cm4all.com, linux-kernel@vger.kernel.org Subject: Re: Regression in 5.1.20: Reading long directory fails Message-ID: <20190906144837.GD17204@fieldses.org> References: <4418877.15LTP4gqqJ@stwm.de> <4198657.JbNDGbLXiX@h2o.as.studentenwerk.mhn.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 03, 2019 at 08:50:39PM -0500, Jason L Tibbitts III wrote: > I asked the XFS folks who mentioned that the issues with 64 bit inodes > are old, constrained to larger filesystems than what I'm using, not an > issue with nfsv4, and not present on anything but 32bit clients with old > userspace. > > In any case, I have been experimenting a bit and somehow the issue seems > to be related to exporting with sec=krb5i:krb5p or sec=krb5i. If I > export with just sec=krb5p, things magically begin to work. That's interesting! We've occasionally had bugs that are rare corner cases in the xdr code--e.g. if the encoded directory data hits some limit at the same time that we reach the end of a page, and the end of the page falls at some offset with respect to the entry we're encoding. Something like switching between krb5i and krb5p could affect the offsets in a way that affected the likelihood of hitting such a case. That's one guess, anyway. > Anyway, I hope this helps to pinpoint the problem. I now have a really > easy way to reproduce this without having to kick people off of the > server, and if the successes aren't just some kind of false positives > then I guess I also have a workaround. I'm still at a loss as to why a > revert of the readdir changes makes any difference at all here. Those readdir changes were client-side, right? Based on that I'd been assuming a client bug, but maybe it'd be worth getting a full packet capture of the readdir reply to make sure it's legit. Looking at it in wireshark should tell us quickly whether it's corrupted somehow. --b.