From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org ([198.137.202.9]:50838 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754622AbcFPPBr (ORCPT ); Thu, 16 Jun 2016 11:01:47 -0400 Received: from hch by bombadil.infradead.org with local (Exim 4.80.1 #2 (Red Hat Linux)) id 1bDYnj-0004xy-1u for linux-nfs@vger.kernel.org; Thu, 16 Jun 2016 15:01:47 +0000 Date: Thu, 16 Jun 2016 08:01:47 -0700 From: Christoph Hellwig To: linux-nfs@vger.kernel.org Subject: odd sillyrename bug in 4.6 / 4.7-rc Message-ID: <20160616150146.GA14015@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-nfs-owner@vger.kernel.org List-ID: I've run into an odd bug when testing the clone / reflink functionality, and managed to isolate a testcase not relying on clones. The issue is that after a lot of direct I/O hitting ENOSPC on a NFS mount I run into a silly rename that never gets cleaned up after cleaning up the directory. Note that so far I've only managed to reproduce it against a Linux server running XFS (ext4 and btrfs seem fine) despite looking like a client bug, and although once in a while a single run of the testcase cause the bug I usually need a few iterations. All over it seems like some odd dentry refcount race where we see a spurious reference for one reason or another. Below is a patch to xfstests to add this reproducer: diff --git a/tests/generic/700 b/tests/generic/700 new file mode 100755 index 0000000..33505b0 --- /dev/null +++ b/tests/generic/700 @@ -0,0 +1,130 @@ +#! /bin/bash +# FS QA Test No. 700 +# +# Dumbed down Copy of the original version of generic/187 that reproduced +# NFS silly rename issues. +#----------------------------------------------------------------------- +# Copyright (c) 2015, Oracle and/or its affiliates. All Rights Reserved. +# +# This program is free software; you can redistribute it and/or +# modify it under the terms of the GNU General Public License as +# published by the Free Software Foundation. +# +# This program is distributed in the hope that it would be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program; if not, write the Free Software Foundation, +# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA +#----------------------------------------------------------------------- + +seq=`basename $0` +seqres=$RESULT_DIR/$seq +echo "QA output created by $seq" + +here=`pwd` +tmp=/tmp/$$ +status=1 # failure is the default! +trap "_cleanup; exit \$status" 0 1 2 3 15 + +_cleanup() +{ + cd / + rm -rf $tmp.* $testdir +} + +# get standard environment, filters and checks +. ./common/rc +. ./common/filter + +# real QA test starts here +_supported_os Linux +_require_xfs_io_command "falloc" +_require_xfs_io_command "fpunch" +test $FSTYP = "btrfs" && _notrun "Can't fragment free space on btrfs." +_require_odirect + +rm -f $seqres.full + +_fragment_freesp() +{ + file=$1 + + # consume nearly all available space (leave ~1MB) + avail=`_get_available_space $SCRATCH_MNT` + echo "$avail bytes left" + filesize=$((avail - 1048576)) + $XFS_IO_PROG -fc "truncate $filesize" $file + + chunks=20 + chunksizemb=$((filesize / chunks / 1048576)) + seq 1 $chunks | while read f; do + echo "$((f * chunksizemb)) file size $f / 20" + $XFS_IO_PROG -fc "falloc -k $(( (f - 1) * chunksizemb))m ${chunksizemb}m" $file + done + + chunks=100 + chunksizemb=$((filesize / chunks / 1048576)) + seq 80 $chunks | while read f; do + echo "$((f * chunksizemb)) file size $f / $chunks" + $XFS_IO_PROG -fc "falloc -k $(( (f - 1) * chunksizemb))m ${chunksizemb}m" $file + done + + filesizemb=$((filesize / 1048576)) + $XFS_IO_PROG -fc "falloc -k 0 ${filesizemb}m" $file + + # Try again anyway + avail=`_get_available_space $SCRATCH_MNT` + $XFS_IO_PROG -fc "pwrite -S 0x65 0 $avail" ${file}.${i} + + # Punch out whatever we need + seq 1 $((nr * 4)) | while read f; do + $XFS_IO_PROG -f -c "fpunch $((f * 2 * blksz)) $blksz" $file + done +} + +echo "Format and mount" +_scratch_mkfs > $seqres.full 2>&1 +_scratch_mount >> $seqres.full 2>&1 + +testdir=$SCRATCH_MNT/test-$seq +mkdir $testdir + +echo "Create the original files" +blksz=65536 +nr=1024 +filesize=$((blksz * nr)) +_pwrite_byte 0x61 0 $filesize $testdir/file1 >> $seqres.full +_pwrite_byte 0x62 0 $filesize $testdir/file2 >> $seqres.full +seq 0 2 $((nr-1)) | while read f; do +# _reflink_range $testdir/file1 $((blksz * f)) $testdir/file3 $((blksz * f)) $blksz >> $seqres.full + touch $testdir/file3 + _pwrite_byte 0x61 $((blksz * f)) $blksz $testdir/file3.chk >> $seqres.full +done +seq 1 2 $((nr-1)) | while read f; do + touch $testdir/file3 +# _reflink_range $testdir/file2 $((blksz * f)) $testdir/file3 $((blksz * f)) $blksz >> $seqres.full + _pwrite_byte 0x62 $((blksz * f)) $blksz $testdir/file3.chk >> $seqres.full +done +_scratch_cycle_mount +_fragment_freesp $testdir/bigfile >> $seqres.full 2>&1 +filesize=$((blksz * nr)) +_scratch_cycle_mount + +echo "Overwrite" +cowoff=$((filesize / 4)) +cowsz=$((filesize / 2)) +$XFS_IO_PROG -d -f -c "pwrite -S 0x63 -b $cowsz $cowoff $cowsz" $testdir/file3 >> $seqres.full +_pwrite_byte 0x63 $cowoff $cowsz $testdir/file3.chk >> $seqres.full + +# mount / unmount +_scratch_cycle_mount + +echo "Deleting" +rm -r $testdir + +# success, all done +status=0 +exit diff --git a/tests/generic/700.out b/tests/generic/700.out new file mode 100644 index 0000000..9f7ce0f --- /dev/null +++ b/tests/generic/700.out @@ -0,0 +1,5 @@ +QA output created by 700 +Format and mount +Create the original files +Overwrite +Deleting diff --git a/tests/generic/group b/tests/generic/group index 2bd40a1..46a796a 100644 --- a/tests/generic/group +++ b/tests/generic/group @@ -354,6 +354,7 @@ 349 blockdev quick rw 350 blockdev quick rw 351 blockdev quick rw +700 auto nfs 923 auto quick clone 924 auto quick clone 925 auto quick clone