Re: [PATCH v3 1/2] f2fs/006: add testcase to check out-of-space case

[Chao Yu <chao@kernel.org>]

On 2024/10/29 14:09, Zorro Lang wrote:
> On Mon, Oct 28, 2024 at 10:17:59PM +0800, Chao Yu wrote:
>> This is a regression test to check whether f2fs handles dirty
>> data correctly when checkpoint is disabled, if lfs mode is on,
>> it will trigger OPU for all overwritten data, this will cost
>> free segments, so f2fs must account overwritten data as OPU
>> data when calculating free space, otherwise, it may run out
>> of free segments in f2fs' allocation function. If kernel config
>> CONFIG_F2FS_CHECK_FS is on, it will cause system panic, otherwise,
>> dd may encounter I/O error.
>>
>> Cc: Jaegeuk Kim <jaegeuk@kernel.org>
>> Signed-off-by: Chao Yu <chao@kernel.org>
>> ---
>> v3:
>> - explain more about behavior on kernel w/ different config
>> - use _filter_scratch to filter $SCRATCH_MNT
>>   tests/f2fs/006     | 42 ++++++++++++++++++++++++++++++++++++++++++
>>   tests/f2fs/006.out |  6 ++++++
>>   2 files changed, 48 insertions(+)
>>   create mode 100755 tests/f2fs/006
>>   create mode 100644 tests/f2fs/006.out
>>
>> diff --git a/tests/f2fs/006 b/tests/f2fs/006
>> new file mode 100755
>> index 00000000..f9560b2b
>> --- /dev/null
>> +++ b/tests/f2fs/006
>> @@ -0,0 +1,42 @@
>> +#! /bin/bash
>> +# SPDX-License-Identifier: GPL-2.0
>> +# Copyright (c) 2024 Oppo.  All Rights Reserved.
>> +#
>> +# FS QA Test No. f2fs/006
>> +#
>> +# This is a regression test to check whether f2fs handles dirty
>> +# data correctly when checkpoint is disabled, if lfs mode is on,
>> +# it will trigger OPU for all overwritten data, this will cost
>> +# free segments, so f2fs must account overwritten data as OPU
>> +# data when calculating free space, otherwise, it may run out
>> +# of free segments in f2fs' allocation function. If kernel config
>> +# CONFIG_F2FS_CHECK_FS is on, it will cause system panic, otherwise,
>> +# dd may encounter I/O error.
>> +#
>> +. ./common/preamble
>> +_begin_fstest auto quick
>> +
>> +_fixed_by_kernel_commit xxxxxxxxxxxx \
>> +	"f2fs: fix to account dirty data in __get_secs_required()"
>> +
>> +# Import common functions.
>> +. ./common/filter
>> +
>> +_require_scratch
>> +_scratch_mkfs_sized $((1024*1024*100)) >> $seqres.full
>> +
>> +# use mode=lfs to let f2fs always triggers OPU
>> +_scratch_mount -o mode=lfs,checkpoint=disable:10%,noinline_dentry >> $seqres.full
>> +
>> +testfile=$SCRATCH_MNT/testfile
>> +
>> +dd if=/dev/zero of=$testfile bs=1M count=50 2>/dev/null
>> +
>> +# it may run out of free space of f2fs and hang kernel
>> +dd if=/dev/zero of=$testfile bs=1M count=50 conv=notrunc conv=fsync
>> +dd if=/dev/zero of=$testfile bs=1M count=50 conv=notrunc conv=fsync 2>&1 | _filter_scratch
>> +
>> +_scratch_remount checkpoint=enable
>> +
>> +status=0
>> +exit
>> diff --git a/tests/f2fs/006.out b/tests/f2fs/006.out
>> new file mode 100644
>> index 00000000..2dc9efda
>> --- /dev/null
>> +++ b/tests/f2fs/006.out
>> @@ -0,0 +1,6 @@
>> +QA output created by 006
>> +50+0 records in
>> +50+0 records out
>> +dd: error writing 'SCRATCH_MNT/testfile': No space left on device
>> +3+0 records in
>> +2+0 records out
> 
> Hi Chao,
> 
> One more question about this patch.
> 
> I'm wondering can this output always be matched? If the test doesn't care the dd output,
> you can filter out them, to avoid it break golden image. Especially the second one, can
> you be sure it always "3 in and 2 out" before returning ENOSPC?

Zorro,

I got your concern, how about using _check_dmesg to catch the kernel
bug instead? since once the bug was triggered, f2fs will call BUG_ON
or WARN_ON optionally anyway.

Thanks,

> 
> Thanks,
> Zorro
> 
>> -- 
>> 2.40.1
>>
>