Message-ID: <7b70e66ec03fecd9f0d93f77c737393fa4ab7fb5.camel@kernel.org>
Subject: Re: [PATCH 0/7] lockd: fix races that can result in stuck filelocks
From:   Jeff Layton <jlayton@kernel.org>
To:     Amir Goldstein <amir73il@gmail.com>,
        Chuck Lever III <chuck.lever@oracle.com>
Cc:     Trond Myklebust <trond.myklebust@hammerspace.com>,
        Anna Schumaker <anna@kernel.org>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        "yoyang@redhat.com" <yoyang@redhat.com>
Date:   Mon, 13 Mar 2023 06:45:24 -0400
In-Reply-To: <CAOQ4uxhwN9Lgzn0_YB33Jfzy1idRene2=tBrr4s9T5PYefJm_Q@mail.gmail.com>
References: <20230303121603.132103-1-jlayton@kernel.org>
         <0FC66364-4F59-4590-9211-EB54E918C97D@oracle.com>
         <CAOQ4uxhwN9Lgzn0_YB33Jfzy1idRene2=tBrr4s9T5PYefJm_Q@mail.gmail.com>
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On Sun, 2023-03-12 at 17:33 +0200, Amir Goldstein wrote:
> On Fri, Mar 3, 2023 at 4:54=E2=80=AFPM Chuck Lever III <chuck.lever@oracl=
e.com> wrote:
> >=20
> >=20
> >=20
> > > On Mar 3, 2023, at 7:15 AM, Jeff Layton <jlayton@kernel.org> wrote:
> > >=20
> > > I sent the first patch in this series the other day, but didn't get a=
ny
> > > responses.
> >=20
> > We'll have to work out who will take which patches in this set.
> > Once fully reviewed, I can take the set if the client maintainers
> > send Acks for 2-4 and 6-7.
> >=20
> > nfsd-next for v6.4 is not yet open. I can work on setting that up
> > today.
> >=20
> >=20
> > > Since then I've had time to follow up on the client-side part
> > > of this problem, which eventually also pointed out yet another bug on
> > > the server side. There are also a couple of cleanup patches in here t=
oo,
> > > and a patch to add some tracepoints that I found useful while diagnos=
ing
> > > this.
> > >=20
> > > With this set on both client and server, I'm now able to run Yongchen=
g's
> > > test for an hour straight with no stuck locks.
>=20
> My nfstest_lock test occasionally gets into an endless wait loop for the =
lock in
> one of the optests.
>=20
> AFAIK, this started happening after I upgraded my client machine to v5.15=
.88.
> Does this seem related to the client bug fixes in this patch set?
>=20
> If so, is this bug a regression? and why are the fixes aimed for v6.4?
>=20

Most of this (lockd) code hasn't changed in well over a decade, so if
this is a regression then it's a very old one. I suppose it's possible
that this regressed after the BKL was removed from this code, but that
was a long time ago now and I'm not sure I can identify a commit that
this fixes.

I'm fine with this going in sooner than v6.4, but given that this has
been broken so long, I didn't see the need to rush.

Cheers,
--=20
Jeff Layton <jlayton@kernel.org>