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Subject: Re: NFS Mount Hangs
From:   Jason Breitman <jbreitman@tildenparkcapital.com>
In-Reply-To: <2b13577bb30faf3b475d2d602be57aa135023a53.camel@hammerspace.com>
Date:   Mon, 8 Mar 2021 17:22:10 -0500
Cc:     "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>
Message-Id: <15CD7763-6DE5-4DBA-8FAE-859964AA90AC@tildenparkcapital.com>
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 <2b13577bb30faf3b475d2d602be57aa135023a53.camel@hammerspace.com>
To:     Trond Myklebust <trondmy@hammerspace.com>
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Thank you.
Do you know which kernel version is fixed?
If not, is there something I can look for in the source code that will indicate that the kernel is fixed.

Jason Breitman


On Mar 8, 2021, at 5:15 PM, Trond Myklebust <trondmy@hammerspace.com> wrote:

On Mon, 2021-03-08 at 13:16 -0500, Jason Breitman wrote:
> Issue
> NFSv4 mounts periodically hang on the NFS Client.
> 
> During this time, it is possible to manually mount from another NFS
> Server on the NFS Client having issues.
> Also, other NFS Clients are successfully mounting from the NFS Server
> in question.
> Rebooting the NFS Client appears to be the only solution.
> 
> I believe this issue has been discussed in the past so I included an
> article that matched my symptoms.
> I do not see a case statement for FIN_WAIT2 at
> https://elixir.bootlin.com/linux/v4.19.171/source/net/sunrpc/xprtsock.c
> .
> 
> NFS Client
> OS:             Debian Buster 10.8
> Kernel: 4.19.171-2
> Protocol:       NFSv4 with Kerberos Security
> Mount Options:  nfs-
> server.domain.com:/data     /mnt/data       nfs4    lookupcache=pos,n
> oresvport,sec=krb5,hard,rsize=1048576,wsize=1048576    00
> 
> Output from the NFS Client when the issue occurs
> # netstat -an | grep NFS.Server.IP.X
> tcp        0      0 NFS.Client.IP.X:46896     
> NFS.Server.IP.X:2049       FIN_WAIT2
> 

Your client has closed the connection, and is waiting for the server to
close the connection on its side.

I'd suggest using a newer kernel, or else getting someone in the Debian
project to fix theirs.

-- 
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@hammerspace.com