On 2019/9/14 1:36, Brian Foster wrote:
> On Wed, Sep 11, 2019 at 09:17:08PM +0800, kaixuxia wrote:
>> There is ABBA deadlock bug between the AGI and AGF when performing
>> rename() with RENAME_WHITEOUT flag, and add this testcase to make
>> sure the rename() call works well.
>>
>> Signed-off-by: kaixuxia <kaixuxia@xxxxxxxxxxx>
>> ---
>> tests/xfs/512 | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> tests/xfs/512.out | 2 ++
>> tests/xfs/group | 1 +
>> 3 files changed, 102 insertions(+)
>> create mode 100755 tests/xfs/512
>> create mode 100644 tests/xfs/512.out
>>
>> diff --git a/tests/xfs/512 b/tests/xfs/512
>> new file mode 100755
>> index 0000000..754f102
>> --- /dev/null
>> +++ b/tests/xfs/512
>> @@ -0,0 +1,99 @@
>> +#! /bin/bash
>> +# SPDX-License-Identifier: GPL-2.0
>> +# Copyright (c) 2019 Tencent. All Rights Reserved.
>> +#
>> +# FS QA Test 512
>> +#
>> +# Test the ABBA deadlock case between the AGI and AGF When performing
>> +# rename operation with RENAME_WHITEOUT flag.
>> +#
>> +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 -f $tmp.*
>> +}
>> +
>> +# get standard environment, filters and checks
>> +. ./common/rc
>> +. ./common/filter
>> +. ./common/renameat2
>> +
>> +rm -f $seqres.full
>> +
>> +# real QA test starts here
>> +_supported_fs xfs
>> +_supported_os Linux
>> +_require_scratch_nocheck
>
> Why _nocheck? AFAICT the filesystem shouldn't end up intentionally
> corrupted.
Will add the comment in the next version.
>
>> +_requires_renameat2 whiteout
>> +
>> +prepare_file()
>> +{
>> + # create many small files for the rename with RENAME_WHITEOUT
>> + i=0
>> + while [ $i -le $files ]; do
>> + file=$SCRATCH_MNT/f$i
>> + echo > $file >/dev/null 2>&1
>> + let i=$i+1
>> + done
>
> Something like the following is a bit more simple, IMO:
>
> for i in $(seq 1 $files); do
> touch $SCRATCH_MNT/f.$i
> done
>
> The same goes for the other while loops below that increment up to
> $files.
>
>> +}
>> +
>> +rename_whiteout()
>> +{
>> + # create the rename targetdir
>> + renamedir=$SCRATCH_MNT/renamedir
>> + mkdir $renamedir
>> +
>> + # a long filename could increase the possibility that target_dp
>> + # allocate new blocks(acquire the AGF lock) to store the filename
>> + longnamepre=FFFsafdsagafsadfagasdjfalskdgakdlsglkasdg
>> +
>
> The max filename length is 256 bytes. You could do something like the
> following to increase name length (leaving room for the file index and
> terminating NULL) if it helps the test:
>
> prefix=`for i in $(seq 0 245); do echo -n a; done`
>
>> + # now try to do rename with RENAME_WHITEOUT flag
>> + i=0
>> + while [ $i -le $files ]; do
>> + src/renameat2 -w $SCRATCH_MNT/f$i $renamedir/$longnamepre$i >/dev/null 2>&1
>> + let i=$i+1
>> + done
>> +}
>> +
>> +create_file()
>> +{
>> + # create the targetdir
>> + createdir=$SCRATCH_MNT/createdir
>> + mkdir $createdir
>> +
>> + # try to create file at the same time to hit the deadlock
>> + i=0
>> + while [ $i -le $files ]; do
>> + file=$createdir/f$i
>> + echo > $file >/dev/null 2>&1
>> + let i=$i+1
>> + done
>> +}
>
> You could generalize this function to take a target directory parameter
> and just call it twice (once to prepare and again for the create
> workload).
Right.
>
>> +
>> +_scratch_mkfs_xfs -bsize=1024 -dagcount=1 >> $seqres.full 2>&1 ||
>> + _fail "mkfs failed"
>
> Why -bsize=1k? Does that make the reproducer more effective?
>
The smaller block size, the more frequently that the blocks are allocated
when creating files...
>> +_scratch_mount
>> +
>> +files=250000
>> +
>
> Have you tested effectiveness of reproducing the issue with smaller file
> counts? A brief comment here to document where the value comes from
> might be useful. Somewhat related, how long does this test take on fixed
> kernels?
Hmm, 250000 is just a random number big enough for this test. The smaller
file counts maybe is enough. Actually, the create_file() call run fast
than the rename_whiteout() call, so we can choose two different file
counts for them. Anyway, I would address the file counts problem in V3...
>
>> +prepare_file
>> +rename_whiteout &
>> +create_file &
>> +
>> +wait
>> +echo Silence is golden
>> +
>> +# Failure comes in the form of a deadlock.
>> +
>
> I wonder if this should be in the dangerous group as well. I go back and
> forth on that though because I tend to filter out dangerous tests and
> the test won't be so risky once the fix proliferates. Perhaps that's
> just a matter of removing it from the dangerous group after a long
> enough period of time.
>
> Brian
>
>> +# success, all done
>> +status=0
>> +exit
>> diff --git a/tests/xfs/512.out b/tests/xfs/512.out
>> new file mode 100644
>> index 0000000..0aabdef
>> --- /dev/null
>> +++ b/tests/xfs/512.out
>> @@ -0,0 +1,2 @@
>> +QA output created by 512
>> +Silence is golden
>> diff --git a/tests/xfs/group b/tests/xfs/group
>> index a7ad300..ed250d6 100644
>> --- a/tests/xfs/group
>> +++ b/tests/xfs/group
>> @@ -509,3 +509,4 @@
>> 509 auto ioctl
>> 510 auto ioctl quick
>> 511 auto quick quota
>> +512 auto rename
>> --
>> 1.8.3.1
>>
>> --
>> kaixuxia
--
kaixuxia
