From:   "Benjamin Coddington" <bcodding@redhat.com>
To:     "Trond Myklebust" <trondmy@hammerspace.com>
Cc:     anna.schumaker@netapp.com, linux-nfs@vger.kernel.org
Subject: Re: [PATCH] NFS: Don't use page_file_mapping after removing the page
Date:   Mon, 04 Feb 2019 14:07:24 -0500
Message-ID: <C1BFD544-69A6-4AE4-87EA-2C711C6ABB3B@redhat.com>
In-Reply-To: <22D43CDC-BB14-4C8F-A10E-DF7816EBF0B0@redhat.com>
References: <b85247642d77ea12153d042a4dce85b94d7624ca.1549303962.git.bcodding@redhat.com>
 <c525031691d77cff46adc30dc16bf1d19fb46900.camel@hammerspace.com>
 <22D43CDC-BB14-4C8F-A10E-DF7816EBF0B0@redhat.com>
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On 4 Feb 2019, at 14:03, Benjamin Coddington wrote:

> On 4 Feb 2019, at 13:32, Trond Myklebust wrote:
>
>> On Mon, 2019-02-04 at 13:13 -0500, Benjamin Coddington wrote:
>>> If nfs_page_async_flush() removes the page from the mapping, then we
>>> can't
>>> use page_file_mapping() on it as nfs_updatepate() is wont to do when
>>> receiving an error.  Instead, simplify nfs_zap_mapping() to take the
>>> inode.
>>>
>>
>> Won't this break NFS swap?
>
> I guess it may, but then I wonder: is that a thing that anyone does?  It
> sounds like a terrible idea..
>
> I'm curious enough though, and doing some research on it.

There's enough to commits in the tree fixing problem or supporting swap on
NFS, so I suppose I've just missed all that.

.. back to the code to find another way.

Ben