On Tue, Dec 13, 2016 at 5:35 AM, Eryu Guan <eguan@xxxxxxxxxx> wrote: > On Mon, Dec 12, 2016 at 12:29:21PM +0200, Amir Goldstein wrote: >> Introduce a new test to demonstrate a known issue with overlayfs: >> - file A and B are hardlinked in lower >> - modify A to trigger copy up >> - file A is no longer a hardlink of file B >> >> There is no fix for this issue at this time. > > Is this something we want to fix eventually? This is a question for Miklos to answer, but here is a quote from him on the stable inode POC thread: https://marc.info/?l=linux-unionfs&m=148045641305234&w=3 "... The following issues are left: - performance of readdir; - what to do if not all layers are on the same fs; - hard link copy ups. " > If not, do we want a test > that is failing forever? I ask because I heard that this is something > not easy/worth fixing, at least low priority. But things may change now. > And another quote from Miklos on an answer to similar question on the overlay/016 tests thread: https://marc.info/?l=fstests&m=148041025721866&w=3 "... > What is the preferred timing for merging these sort of tests? > Is it productive to have these tests merged before a fix is merged to master? > Before a fix is queued for next? > Before a fix is available? IMO adding a test doesn't hurt, it'll just indicate that the current version is broken. It doesn't have to have any synchronization with the actual fix. " >> >> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx> >> --- >> tests/overlay/019 | 88 +++++++++++++++++++++++++++++++++++++++++++++++++++ >> tests/overlay/019.out | 2 ++ >> tests/overlay/group | 1 + >> 3 files changed, 91 insertions(+) >> create mode 100755 tests/overlay/019 >> create mode 100644 tests/overlay/019.out >> >> diff --git a/tests/overlay/019 b/tests/overlay/019 >> new file mode 100755 >> index 0000000..382e4ee >> --- /dev/null >> +++ b/tests/overlay/019 >> @@ -0,0 +1,88 @@ >> +#! /bin/bash >> +# FSQA Test No. 019 >> +# >> +# Test hardlink breakage >> +# >> +# This simple test demonstrates a known issue with overlayfs: >> +# - file A and B are hardlinked in lower >> +# - modify A to trigger copy up >> +# - file A is no longer a hardlink of file B >> +# >> +#----------------------------------------------------------------------- >> +# >> +# Copyright (C) 2016 CTERA Networks. All Rights Reserved. >> +# Author: Amir Goldstein <amir73il@xxxxxxxxx> >> +# >> +# 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" >> + >> +tmp=/tmp/$$ >> +status=1 # failure is the default! >> +trap "_cleanup; exit \$status" 0 1 2 3 15 >> + >> +_cleanup() >> +{ >> + cd / >> + rm -f $tmp.* >> +} >> + >> +# get standard environment, filters and checks >> +. ./common/rc >> +. ./common/filter >> + >> +# real QA test starts here >> +_supported_fs overlay >> +_supported_os Linux >> +_require_scratch >> + >> +rm -f $seqres.full >> + >> +_scratch_mkfs >>$seqres.full 2>&1 >> + >> +# Create 2 hardlinked files in lower >> +lowerdir=$SCRATCH_DEV/$OVERLAY_LOWER_DIR >> +mkdir -p $lowerdir >> +echo "patient zero" >> $lowerdir/foo >> +ln $lowerdir/foo $lowerdir/bar >> + >> + >> +_scratch_mount >> + >> +cd $SCRATCH_MNT > > It's uncommon to cd to $SCRATCH_MNT in fstests, if it can be done > without doing so. Usually we do > > testfile1=$SCRATCH_MNT/foo > testfile2=$SCRATCH_MNT/bar > > <do tests on $testfile1 and $testfile2> > > Can this test be updated in this way? And patch "overlay: test unstable > inode number"? Sorry that I forgot about this yesterday.. > No problem. > Thanks! > > Eryu > >> + >> +rm -f $tmp.before $tmp.after >> + >> +# Record inode number and nlink before copy up >> +ls -li foo bar | awk '{ print $1, $3 }' > $tmp.before >> + >> +# Modify content of one of the hardlinks >> +echo "mutated" >> foo >> + >> +# Record inode number and nlink after copy up >> +ls -li foo bar | awk '{ print $1, $3 }' > $tmp.after >> + >> +# Compare ino/nlink before..after - expect silence >> +diff $tmp.before $tmp.after >> + >> +# Compare content of files - expect silence >> +diff foo bar >> + >> +echo "Silence is golden" >> +status=0 >> +exit >> diff --git a/tests/overlay/019.out b/tests/overlay/019.out >> new file mode 100644 >> index 0000000..163484b >> --- /dev/null >> +++ b/tests/overlay/019.out >> @@ -0,0 +1,2 @@ >> +QA output created by 019 >> +Silence is golden >> diff --git a/tests/overlay/group b/tests/overlay/group >> index fb6610d..f266b0a 100644 >> --- a/tests/overlay/group >> +++ b/tests/overlay/group >> @@ -20,3 +20,4 @@ >> 015 auto quick whiteout >> 016 auto quick copyup >> 018 auto quick copyup >> +019 auto quick copyup >> -- >> 2.7.4 >> -- To unsubscribe from this list: send the line "unsubscribe fstests" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
