From:   Chuck Lever III <chuck.lever@oracle.com>
To:     Jeff Layton <jlayton@kernel.org>
CC:     Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        "dcritch@redhat.com" <dcritch@redhat.com>,
        "d.lesca@solinos.it" <d.lesca@solinos.it>
Subject: Re: [PATCH 1/2] nfsd: don't replace page in rq_pages if it's a
 continuation of last page
Thread-Topic: [PATCH 1/2] nfsd: don't replace page in rq_pages if it's a
 continuation of last page
Thread-Index: AQHZWL8bpLhVrwRqqEan4MoWlxHuRa7+8Q2AgAATp4CAAAwUgIAAASiA
Date:   Fri, 17 Mar 2023 15:04:05 +0000
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References: <20230317105608.19393-1-jlayton@kernel.org>
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> On Mar 17, 2023, at 10:59 AM, Jeff Layton <jlayton@kernel.org> wrote:
>=20
> On Fri, 2023-03-17 at 14:16 +0000, Chuck Lever III wrote:
>=20
>> In the patch description, would you mention that this case
>> arises if the READ request is not page-aligned?
>=20
> Does it though? I'm not sure that page alignment has that much to do
> with it. I imagine you can hit this even with aligned I/Os.

Maybe, but no-one has actually seen that. The vast majority of
reports of this problem are with unaligned I/O, which POSIX OS
NFS clients (like the Linux NFS client) usually avoid.

I didn't mean to exclude the possibility of hitting this issue
in other ways, but simply observing a common way it is hit.


--
Chuck Lever