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From: Christoph Hellwig <hch@lst.de>
To: Brian Foster <bfoster@redhat.com>
Cc: Paul Menzel <pmenzel@molgen.mpg.de>,
	linux-nfs@vger.kernel.org, linux-xfs@vger.kernel.org,
	it+linux-nfs@molgen.mpg.de, Christoph Hellwig <hch@lst.de>
Subject: Re: Locking problems with Linux 4.9 with NFSD and `fs/iomap.c`
Date: Tue, 9 May 2017 11:05:34 +0200	[thread overview]
Message-ID: <20170509090534.GB2378@lst.de> (raw)
In-Reply-To: <20170508131843.GB29840@bfoster.bfoster>

On Mon, May 08, 2017 at 09:18:46AM -0400, Brian Foster wrote:
> What exactly is a NULL call? Can this be reproduced easily?

It's a sunrpc concept of a dummy procedure that does nothing but
ensures the communication works.

> It may also be interesting to enable the xfs_zero_eof() tracepoint
> (trace-cmd start -e 'xfs:xfs_zero_eof') and see what the last few
> entries are from /sys/kernel/debug/tracing/trace_pipe.

Yeah.  I have a customer that uses Linux 4.9-stable with XFS and
nfsd exports in a product, so it's certainly not something that happens
too easily, but memory pressure might be a factor.   I'll see if
I can figure out what happens if I inject ENOMEM in the said
spot.

  reply	other threads:[~2017-05-09  9:05 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-07 19:09 Locking problems with Linux 4.9 with NFSD and `fs/iomap.c` Paul Menzel
2017-05-08 13:18 ` Brian Foster
2017-05-09  9:05   ` Christoph Hellwig [this message]
     [not found]     ` <7ae18b0d-38e3-9b12-0989-ede68956ad43@molgen.mpg.de>
     [not found]       ` <358037e8-6784-ebca-9fbb-ec7eef3977d6@molgen.mpg.de>
     [not found]         ` <20170510171757.GA10534@localhost.localdomain>
2017-06-27 11:59           ` Locking problems with Linux 4.9 and 4.11 " Paul Menzel
2017-06-28 16:41             ` Christoph Hellwig
2017-08-01 17:49             ` Paul Menzel
2017-08-01 22:51               ` Dave Chinner
2017-08-10 14:11                 ` Paul Menzel
2017-08-10 19:54                   ` AW: " Markus Stockhausen
2017-08-11 10:15                     ` Christoph Hellwig
2017-08-11 15:14                       ` Paul Menzel
2017-05-10  9:08   ` Locking problems with Linux 4.9 " Paul Menzel
2017-05-10 17:23     ` J. Bruce Fields

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