From: "J. Bruce Fields" <bfields@fieldses.org>
To: Jason L Tibbitts III <tibbs@math.uh.edu>
Cc: Wolfgang Walter <linux@stwm.de>,
linux-nfs@vger.kernel.org, km@cm4all.com,
linux-kernel@vger.kernel.org
Subject: Re: Regression in 5.1.20: Reading long directory fails
Date: Fri, 6 Sep 2019 10:48:37 -0400 [thread overview]
Message-ID: <20190906144837.GD17204@fieldses.org> (raw)
In-Reply-To: <ufad0ggrfrk.fsf@epithumia.math.uh.edu>
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.
next prev parent reply other threads:[~2019-09-06 14:48 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-13 15:08 Regression in 5.1.20: Reading long directory fails Jason L Tibbitts III
2019-08-13 17:00 ` Jason L Tibbitts III
2019-08-22 19:39 ` Jason L Tibbitts III
2019-08-28 17:46 ` J. Bruce Fields
2019-08-28 18:29 ` Jason L Tibbitts III
2019-08-28 18:33 ` J. Bruce Fields
2019-09-03 15:49 ` Jason L Tibbitts III
2019-09-03 18:02 ` Wolfgang Walter
2019-09-03 19:06 ` Jason L Tibbitts III
2019-09-03 19:08 ` Chuck Lever
2019-09-03 21:37 ` Wolfgang Walter
2019-09-04 1:50 ` Jason L Tibbitts III
2019-09-06 14:48 ` J. Bruce Fields [this message]
2019-09-06 20:47 ` Jason L Tibbitts III
2019-09-06 20:50 ` Chuck Lever
2019-09-08 11:39 ` Benjamin Coddington
2019-09-08 15:19 ` Trond Myklebust
2019-09-08 15:48 ` Chuck Lever
2019-09-08 16:47 ` Trond Myklebust
2019-09-08 16:51 ` Chuck Lever
2019-09-11 16:25 ` Benjamin Coddington
2019-09-11 16:39 ` Chuck Lever
2019-09-11 17:26 ` Benjamin Coddington
2019-09-11 17:27 ` Benjamin Coddington
2019-09-11 17:29 ` Chuck Lever
2019-09-11 17:40 ` Benjamin Coddington
2019-09-11 17:43 ` Chuck Lever
2019-09-11 17:59 ` Benjamin Coddington
2019-09-11 17:50 ` Benjamin Coddington
2019-09-11 17:54 ` Chuck Lever
2019-09-12 12:29 ` Benjamin Coddington
2019-09-12 12:53 ` Trond Myklebust
2019-09-12 13:08 ` Benjamin Coddington
2019-09-12 13:13 ` J. Bruce Fields
2019-09-12 13:25 ` Trond Myklebust
2019-09-12 13:35 ` Benjamin Coddington
2019-09-12 13:14 ` Trond Myklebust
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