Linux-XFS Archive on lore.kernel.org
 help / color / Atom feed
* [PATCH] xfs: test the deadlock between the AGI and AGF with RENAME_WHITEOUT
@ 2019-09-04 10:01 kaixuxia
  2019-09-08 12:39 ` Eryu Guan
  0 siblings, 1 reply; 3+ messages in thread
From: kaixuxia @ 2019-09-04 10:01 UTC (permalink / raw)
  To: fstests; +Cc: linux-xfs, Darrick J. Wong, newtongao, jasperwang

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@tencent.com>
---
 tests/xfs/512     | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/xfs/512.out |   2 ++
 tests/xfs/group   |   1 +
 3 files changed, 103 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..0e95fb7
--- /dev/null
+++ b/tests/xfs/512
@@ -0,0 +1,100 @@
+#! /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
+
+rm -f $seqres.full
+
+# real QA test starts here
+_supported_fs xfs
+_supported_os Linux
+_require_scratch
+
+# Single AG will cause default xfs_repair to fail. This test need a
+# single AG fs, so ignore the check.
+_require_scratch_nocheck
+
+prepare_file()
+{
+	# create many small files for the rename with RENAME_WHITEOUT
+	i=0
+	while [ $i -le $files ]; do
+		file=$SCRATCH_MNT/f$i
+		$XFS_IO_PROG -f -d -c 'pwrite -b 4k 0 4k' $file >/dev/null 2>&1
+		let i=$i+1
+	done
+}
+
+rename_whiteout()
+{
+	# create the rename targetdir
+	renamedir=$SCRATCH_MNT/renamedir
+	mkdir $renamedir
+
+	# just get a random long name...
+	longnamepre=FFFsafdsagafsadfagasdjfalskdgakdlsglkasdg
+
+	# 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
+		$XFS_IO_PROG -f -d -c 'pwrite -b 4k 0 4k' $file >/dev/null 2>&1
+		let i=$i+1
+	done
+}
+
+_scratch_mkfs_xfs -bsize=512 -dagcount=1 >> $seqres.full 2>&1 ||
+	_fail "mkfs failed"
+_scratch_mount
+
+files=250000
+
+prepare_file
+rename_whiteout &
+create_file &
+
+wait
+echo Silence is golden
+
+# Failure comes in the form of a deadlock.
+
+# 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

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] xfs: test the deadlock between the AGI and AGF with RENAME_WHITEOUT
  2019-09-04 10:01 [PATCH] xfs: test the deadlock between the AGI and AGF with RENAME_WHITEOUT kaixuxia
@ 2019-09-08 12:39 ` Eryu Guan
  2019-09-09  9:06   ` kaixuxia
  0 siblings, 1 reply; 3+ messages in thread
From: Eryu Guan @ 2019-09-08 12:39 UTC (permalink / raw)
  To: kaixuxia; +Cc: fstests, linux-xfs, Darrick J. Wong, newtongao, jasperwang

On Wed, Sep 04, 2019 at 06:01:27PM +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@tencent.com>
> ---
>  tests/xfs/512     | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/xfs/512.out |   2 ++
>  tests/xfs/group   |   1 +
>  3 files changed, 103 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..0e95fb7
> --- /dev/null
> +++ b/tests/xfs/512
> @@ -0,0 +1,100 @@
> +#! /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
> +
> +rm -f $seqres.full
> +
> +# real QA test starts here
> +_supported_fs xfs
> +_supported_os Linux
> +_require_scratch

Only _require_scratch_nocheck is suffiecient.

> +
> +# Single AG will cause default xfs_repair to fail. This test need a
> +# single AG fs, so ignore the check.
> +_require_scratch_nocheck

Also need to 

. ./common/rename
...

_requires_renameat2

Also, this test requires RENAME_WHITEOUT, I'd suggest enhance
src/renameat2.c to support check for if a given rename flag is supported
by kernel, and refactor the checks in generic/02[45] and generic/078
into _requires_renameat2 to use the new functionality. e.g.

# without option, behavior stays unchanged, check for renameat2 syscall
# support
_requires_renameat2

# check if renameat2 upports RENAME_WHITEOUT flag
_requires_renameat2 whiteout

# check if renameat2 upports RENAME_EXCHANGE flag
_requires_renameat2 exchange

> +
> +prepare_file()
> +{
> +	# create many small files for the rename with RENAME_WHITEOUT
> +	i=0
> +	while [ $i -le $files ]; do
> +		file=$SCRATCH_MNT/f$i
> +		$XFS_IO_PROG -f -d -c 'pwrite -b 4k 0 4k' $file >/dev/null 2>&1
> +		let i=$i+1

Creating 250000 4k files take a long time. Does file content really
matters? I guess racing RENAME_WHITEOUT with file creation is enough, is
it possible to just create many empty files? e.g.

		echo > $file

this saves a lot time.

> +	done
> +}
> +
> +rename_whiteout()
> +{
> +	# create the rename targetdir
> +	renamedir=$SCRATCH_MNT/renamedir
> +	mkdir $renamedir
> +
> +	# just get a random long name...
> +	longnamepre=FFFsafdsagafsadfagasdjfalskdgakdlsglkasdg

Better to explain why long file name is required.

> +
> +	# 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
> +		$XFS_IO_PROG -f -d -c 'pwrite -b 4k 0 4k' $file >/dev/null 2>&1
> +		let i=$i+1
> +	done

Same here, does creating empty files work?

> +}
> +
> +_scratch_mkfs_xfs -bsize=512 -dagcount=1 >> $seqres.full 2>&1 ||

This doesn't work because crc is on by default, as crc requires minimum
1k block size. Is 512 block size really needed?

> +	_fail "mkfs failed"
> +_scratch_mount
> +
> +files=250000

If we could reduce file number to create, test could run faster as well.
Running test with less than 250000 files couldn't reproduce the
deadlock?

Thanks,
Eryu

> +
> +prepare_file
> +rename_whiteout &
> +create_file &
> +
> +wait
> +echo Silence is golden
> +
> +# Failure comes in the form of a deadlock.
> +
> +# 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

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] xfs: test the deadlock between the AGI and AGF with RENAME_WHITEOUT
  2019-09-08 12:39 ` Eryu Guan
@ 2019-09-09  9:06   ` kaixuxia
  0 siblings, 0 replies; 3+ messages in thread
From: kaixuxia @ 2019-09-09  9:06 UTC (permalink / raw)
  To: Eryu Guan; +Cc: fstests, linux-xfs, Darrick J. Wong, newtongao, jasperwang


On 2019/9/8 20:39, Eryu Guan wrote:
> On Wed, Sep 04, 2019 at 06:01:27PM +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@tencent.com>
>> ---
>>  tests/xfs/512     | 100 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  tests/xfs/512.out |   2 ++
>>  tests/xfs/group   |   1 +
>>  3 files changed, 103 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..0e95fb7
>> --- /dev/null
>> +++ b/tests/xfs/512
>> @@ -0,0 +1,100 @@
>> +#! /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
>> +
>> +rm -f $seqres.full
>> +
>> +# real QA test starts here
>> +_supported_fs xfs
>> +_supported_os Linux
>> +_require_scratch
> 
> Only _require_scratch_nocheck is suffiecient.

Yeah, will fix it.
> 
>> +
>> +# Single AG will cause default xfs_repair to fail. This test need a
>> +# single AG fs, so ignore the check.
>> +_require_scratch_nocheck
> 
> Also need to 
> 
> . ./common/rename
> ...
> 
> _requires_renameat2
> 
> Also, this test requires RENAME_WHITEOUT, I'd suggest enhance
> src/renameat2.c to support check for if a given rename flag is supported
> by kernel, and refactor the checks in generic/02[45] and generic/078
> into _requires_renameat2 to use the new functionality. e.g.
> 
> # without option, behavior stays unchanged, check for renameat2 syscall
> # support
> _requires_renameat2
> 
> # check if renameat2 upports RENAME_WHITEOUT flag
> _requires_renameat2 whiteout
> 
> # check if renameat2 upports RENAME_EXCHANGE flag
> _requires_renameat2 exchange
> 

Right, this testcase requires RENAME_WHITEOUT, it is necessary that check
whether the given rename flag is supported by kernel. I will try to refactor
the corresponding tests and functions.
>> +
>> +prepare_file()
>> +{
>> +	# create many small files for the rename with RENAME_WHITEOUT
>> +	i=0
>> +	while [ $i -le $files ]; do
>> +		file=$SCRATCH_MNT/f$i
>> +		$XFS_IO_PROG -f -d -c 'pwrite -b 4k 0 4k' $file >/dev/null 2>&1
>> +		let i=$i+1
> 
> Creating 250000 4k files take a long time. Does file content really
> matters? I guess racing RENAME_WHITEOUT with file creation is enough, is
> it possible to just create many empty files? e.g.
> 
> 		echo > $file
> 
> this saves a lot time.

Yeah, create empty files is better.
> 
>> +	done
>> +}
>> +
>> +rename_whiteout()
>> +{
>> +	# create the rename targetdir
>> +	renamedir=$SCRATCH_MNT/renamedir
>> +	mkdir $renamedir
>> +
>> +	# just get a random long name...
>> +	longnamepre=FFFsafdsagafsadfagasdjfalskdgakdlsglkasdg
> 
> Better to explain why long file name is required.
> 
Will add the explanation. The long file name will increase the possibility
that target_dp allocate new blocks(acquire the AGF lock) to store the
filename. 
>> +
>> +	# 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
>> +		$XFS_IO_PROG -f -d -c 'pwrite -b 4k 0 4k' $file >/dev/null 2>&1
>> +		let i=$i+1
>> +	done
> 
> Same here, does creating empty files work?

Yeah.
> 
>> +}
>> +
>> +_scratch_mkfs_xfs -bsize=512 -dagcount=1 >> $seqres.full 2>&1 ||
> 
> This doesn't work because crc is on by default, as crc requires minimum
> 1k block size. Is 512 block size really needed?
> 
>> +	_fail "mkfs failed"
>> +_scratch_mount
>> +
>> +files=250000
> 
> If we could reduce file number to create, test could run faster as well.
> Running test with less than 250000 files couldn't reproduce the
> deadlock?

I used this magic number in my local test environment and reproduced
the deadlock every time. Creating empty files would reduce the 
run time...

Thanks.
> 
> Thanks,
> Eryu
> 
>> +
>> +prepare_file
>> +rename_whiteout &
>> +create_file &
>> +
>> +wait
>> +echo Silence is golden
>> +
>> +# Failure comes in the form of a deadlock.
>> +
>> +# 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

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, back to index

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-09-04 10:01 [PATCH] xfs: test the deadlock between the AGI and AGF with RENAME_WHITEOUT kaixuxia
2019-09-08 12:39 ` Eryu Guan
2019-09-09  9:06   ` kaixuxia

Linux-XFS Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-xfs/0 linux-xfs/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-xfs linux-xfs/ https://lore.kernel.org/linux-xfs \
		linux-xfs@vger.kernel.org linux-xfs@archiver.kernel.org
	public-inbox-index linux-xfs


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-xfs


AGPL code for this site: git clone https://public-inbox.org/ public-inbox