Re: [PATCH 0/3] NFS: Disable READ_PLUS by default

["Mkrtchyan, Tigran" <tigran.mkrtchyan@desy.de>]

I agree with Olga, especially that disabling doesn't fixes my issue.
Unfortunately I have no idea how kernel's vm works, but I am
ready to test as many times as needed.

Thanks,
   Tigran.

----- Original Message -----
> From: "Olga Kornievskaia" <aglo@umich.edu>
> To: "Tigran Mkrtchyan" <tigran.mkrtchyan@desy.de>
> Cc: "schumaker anna" <schumaker.anna@gmail.com>, "linux-nfs" <linux-nfs@vger.kernel.org>, "Anna Schumaker"
> <Anna.Schumaker@netapp.com>
> Sent: Friday, 4 December, 2020 21:00:32
> Subject: Re: [PATCH 0/3] NFS: Disable READ_PLUS by default

> I object to putting the disable patch in, I think we need to fix the problem.
> 
> The current problem is generic/263 is failing because the end of the
> buffer is corrupted since we lost the bytes when hole was expanded. I
> don't know what the solution is: (1) hole expanding handling needs to
> be fixed to not lose data or (2) we shouldnt be reporting that we read
> the bytes we lost.
> 
> On Fri, Dec 4, 2020 at 10:49 AM Mkrtchyan, Tigran
> <tigran.mkrtchyan@desy.de> wrote:
>>
>> Hi Anna,
>>
>> I see problems with gedeviceinfo and bisected it to
>> c567552612ece787b178e3b147b5854ad422a836.
>> The commit itself doesn't look that can break it, but might
>> be can help you find the problem.
>>
>> What I see, that after xdr_read_pages call the xdr stream points
>> to a some random point (or wrong page)
>>
>> Regards,
>>    Tigran.
>>
>>
>> ----- Original Message -----
>> > From: "schumaker anna" <schumaker.anna@gmail.com>
>> > To: "linux-nfs" <linux-nfs@vger.kernel.org>
>> > Cc: "Anna Schumaker" <Anna.Schumaker@Netapp.com>
>> > Sent: Thursday, 3 December, 2020 21:18:38
>> > Subject: [PATCH 0/3] NFS: Disable READ_PLUS by default
>>
>> > From: Anna Schumaker <Anna.Schumaker@Netapp.com>
>> >
>> > I've been scratching my head about what's going on with xfstests generic/091
>> > and generic/263, but I'm not sure what else to look at at this point.
>> > This patchset disables READ_PLUS by default by marking it as a
>> > developer-only kconfig option.
>> >
>> > I also included a couple of patches fixing some other issues that were
>> > noticed while inspecting the code. These patches don't help the tests
>> > pass, but they do fail later on after applying so it does feel like
>> > progress.
>> >
>> > I'm hopeful the remaning issues can be worked out in the future.
>> >
>> > Thanks,
>> > Anna
>> >
>> >
>> > Anna Schumaker (3):
>> >  NFS: Disable READ_PLUS by default
>> >  NFS: Allocate a scratch page for READ_PLUS
>> >  SUNRPC: Keep buf->len in sync with xdr->nwords when expanding holes
>> >
>> > fs/nfs/Kconfig          |  9 +++++++++
>> > fs/nfs/nfs42xdr.c       |  2 ++
>> > fs/nfs/nfs4proc.c       |  2 +-
>> > fs/nfs/read.c           | 13 +++++++++++--
>> > include/linux/nfs_xdr.h |  1 +
>> > net/sunrpc/xdr.c        |  3 ++-
>> > 6 files changed, 26 insertions(+), 4 deletions(-)
>> >
>> > --
> > > 2.29.2