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From: Zhitao Li <zhitao.li@smartx.com>
Date: Thu, 22 Feb 2024 11:05:53 +0800
Message-ID: <CAPKjjnpvO_VUwgxEKu1JP8xNnt0hct6koTtOSxZ0bN1D_55JGg@mail.gmail.com>
Subject: Re: PROBLEM: NFS client IO fails with ERESTARTSYS when another mount
 point with the same export is unmounted with force [NFS] [SUNRPC]
To: Trond Myklebust <trondmy@hammerspace.com>
Cc: "chuck.lever@oracle.com" <chuck.lever@oracle.com>, "tom@talpey.com" <tom@talpey.com>, 
	"anna@kernel.org" <anna@kernel.org>, "Dai.Ngo@oracle.com" <Dai.Ngo@oracle.com>, 
	"jlayton@kernel.org" <jlayton@kernel.org>, "neilb@suse.de" <neilb@suse.de>, 
	"kolga@netapp.com" <kolga@netapp.com>, "huangping@smartx.com" <huangping@smartx.com>, 
	"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>, 
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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Forced unmount is used in a casual way to some degree by our team. We
will adjust the usage of forced unmount and multiple mount points for
the same export.

As you said, all of the above is well known. Actually, this phenomenon
is unexpected for us. Could you give some more information?  Are they
issues? And if they are issues, is there any plan to fix them?

Best regards,
Zhitao Li, in SmartX.

On Wed, Feb 21, 2024 at 9:48=E2=80=AFPM Trond Myklebust <trondmy@hammerspac=
e.com> wrote:
>
> On Wed, 2024-02-21 at 16:20 +0800, Zhitao Li wrote:
> > [You don't often get email from zhitao.li@smartx.com. Learn why this
> > is important at https://aka.ms/LearnAboutSenderIdentification ]
> >
> > Hi, everyone,
> >
> > - Facts:
> > I have a remote NFS export and I mount the same export on two
> > different directories in my OS with the same options. There is an
> > inflight IO under one mounted directory. And then I unmount another
> > mounted directory with force. The inflight IO ends up with "Unknown
> > error 512", which is ERESTARTSYS.
> >
>
> All of the above is well known. That's because forced umount affects
> the entire filesystem. Why are you using it here in the first place? It
> is not intended for casual use.
>
> --
> Trond Myklebust
> Linux NFS client maintainer, Hammerspace
> trond.myklebust@hammerspace.com
>
>