linux-kernel - Re: nfsv2 ref leak in 2.6.24?

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Message-Id: <200710200233.l9K2X5qx015844@agora.fsl.cs.sunysb.edu>
Date:	Fri, 19 Oct 2007 22:33:05 -0400
From:	Erez Zadok <ezk@...sunysb.edu>
To:	Trond Myklebust <trond.myklebust@....uio.no>
Cc:	Erez Zadok <ezk@...sunysb.edu>, bfields@...ldses.org,
	nfs@...ts.sourceforge.net, neilb@...e.de,
	linux-kernel@...r.kernel.org
Subject: Re: nfsv2 ref leak in 2.6.24? 

Trond, good news.  I was able to narrow down the problem to purely the
client-side, probably dcache/readdir related, and I have a shell script that
deterministically triggers the problem each time for me (this is a FC6 image
under Vmware 6.0.1).  Here's a short shell script which reliably triggers
the "lost files" problem -- I create a file via nfs2 on the client side, and
sometimes it doesn't show up in readdir, but it is there if you stat it
directly.

BTW, since this is a client-side bug, I also tried your last set of posted
client patches for Linus, but it didn't help.

Happy hunting. :-)

Erez.

##############################################################################
#!/bin/sh

dd if=/dev/zero of=/tmp/fs.$$.0 bs=1024k count=1 seek=100
losetup /dev/loop0 /tmp/fs.$$.0
mkfs -t ext2 -q /dev/loop0
mkdir -p /n/export/b0
mount -t ext2 /dev/loop0 /n/export/b0
exportfs -o no_root_squash,rw localhost:/n/export/b0
mkdir -p /n/client/b0
mount -t nfs -o nfsvers=2 localhost:/n/export/b0 /n/client/b0

count=0
while true; do
    cfile="/n/client/b0/F.$count"

    if touch $cfile ; then
	echo $cfile created
    else
	echo "touch $cfile failed"
	exit 1
    fi

    if `ls -1 /n/client/b0 | egrep -q F.$count'$'` ; then
	:
    else
	echo "$cfile doesn't exist (but it should)"
	ls -l /n/client/b0
	ls -l /n/export/b0
	stat $cfile
	exit 1
    fi

    let count=count+1
done
##############################################################################
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