Re: [linux-next][XFS][trinity] WARNING: CPU: 32 PID: 31369 at fs/iomap.c:993

From	Jens Axboe <axboe@kernel.dk>
Newsgroups	linux.kernel
Subject	Re: [linux-next][XFS][trinity] WARNING: CPU: 32 PID: 31369 at fs/iomap.c:993
Date	2017-09-18 18:00 +0200
Message-ID	<ur6CK-8bR-9@gated-at.bofh.it> (permalink)
References	<ur5GG-7D9-31@gated-at.bofh.it> <ur69I-82d-9@gated-at.bofh.it> <ur69I-82d-13@gated-at.bofh.it> <ur6jq-85s-47@gated-at.bofh.it> <ur6t4-88P-11@gated-at.bofh.it>
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On 09/18/2017 09:43 AM, Al Viro wrote:
> On Mon, Sep 18, 2017 at 05:39:47PM +0200, Christoph Hellwig wrote:
>> On Mon, Sep 18, 2017 at 09:28:55AM -0600, Jens Axboe wrote:
>>> If it's expected, why don't we kill the WARN_ON_ONCE()? I get it all
>>> the time running xfstests as well.
>>
>> Dave insisted on it to decourage users/applications from mixing
>> mmap and direct I/O.
>>
>> In many ways a tracepoint might be the better way to diagnose these.
> 
> sysctl suppressing those two, perhaps?

I'd rather just make it a trace point, but don't care too much.

The code doesn't even have a comment as to why that WARN_ON() is
there or expected. Seems pretty sloppy to me, not a great way
to "discourage" users to mix mmap/dio.

-- 
Jens Axboe

Thread

Re: [linux-next][XFS][trinity] WARNING: CPU: 32 PID: 31369 at         fs/iomap.c:993 Christoph Hellwig <hch@lst.de> - 2017-09-18 17:30 +0200
  Re: [linux-next][XFS][trinity] WARNING: CPU: 32 PID: 31369 at  fs/iomap.c:993 Jens Axboe <axboe@kernel.dk> - 2017-09-18 17:30 +0200
    Re: [linux-next][XFS][trinity] WARNING: CPU: 32 PID: 31369 at         fs/iomap.c:993 Christoph Hellwig <hch@lst.de> - 2017-09-18 17:40 +0200
      Re: [linux-next][XFS][trinity] WARNING: CPU: 32 PID: 31369 at  fs/iomap.c:993 Al Viro <viro@ZenIV.linux.org.uk> - 2017-09-18 17:50 +0200
        Re: [linux-next][XFS][trinity] WARNING: CPU: 32 PID: 31369 at  fs/iomap.c:993 Jens Axboe <axboe@kernel.dk> - 2017-09-18 18:00 +0200
          Re: [linux-next][XFS][trinity] WARNING: CPU: 32 PID: 31369 at  fs/iomap.c:993 Dave Chinner <david@fromorbit.com> - 2017-09-19 00:00 +0200
    Re: [linux-next][XFS][trinity] WARNING: CPU: 32 PID: 31369 at  fs/iomap.c:993 Dave Chinner <david@fromorbit.com> - 2017-09-18 23:40 +0200
      Re: [linux-next][XFS][trinity] WARNING: CPU: 32 PID: 31369 at  fs/iomap.c:993 Eric Sandeen <sandeen@sandeen.net> - 2017-09-19 00:10 +0200
        Re: [linux-next][XFS][trinity] WARNING: CPU: 32 PID: 31369 at  fs/iomap.c:993 "Darrick J. Wong" <darrick.wong@oracle.com> - 2017-09-19 00:10 +0200
        Re: [linux-next][XFS][trinity] WARNING: CPU: 32 PID: 31369 at  fs/iomap.c:993 Dave Chinner <david@fromorbit.com> - 2017-09-19 00:10 +0200

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