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Subject: Re: [RFC-PATCH] nfsd: provide a procfs entry to release stateids of a
 particular local filesystem
From:   Chuck Lever <chuck.lever@oracle.com>
In-Reply-To: <CANHi-ReAFifZwBrRniLBiRnQOWeJKu-EYp18LDHwtr50eifVMw@mail.gmail.com>
Date:   Tue, 17 Sep 2019 10:16:20 -0400
Cc:     alex@zadara.com, Linux NFS Mailing List <linux-nfs@vger.kernel.org>
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 <CANHi-ReAFifZwBrRniLBiRnQOWeJKu-EYp18LDHwtr50eifVMw@mail.gmail.com>
To:     John Gallagher <john.gallagher@delphix.com>
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> On Sep 16, 2019, at 6:28 PM, John Gallagher =
<john.gallagher@delphix.com> wrote:
>=20
> On Tue, Sep 3, 2019 at 6:57 AM Alex Lyakas <alex@zadara.com> wrote:
>> This patch allows user-space to tell nfsd to release stateids of a =
particular local filesystem.
>> After that, it is possible to unmount the local filesystem.
>=20
> We recently ran into this exact same issue. A solution along these
> lines would be very useful to us as well. I am curious, though, is it
> feasible to release all state related to a filesystem immediately when
> it is unexported? It seems like that would be ideal from the
> perspective of the administrator of the server, but perhaps there are
> technical reasons why that isn't easy or even possible.

My two cents: I was surprised by Bruce's claim that simply unexporting a
local filesystem does not reliably render it unmountable. IMO that =
behavior
would also be surprising (and possibly inconvenient) to server =
administrators,
especially in this era of elastic and automated system configuration.


--
Chuck Lever