Re: [PATCH v2] fstests: btrfs: check qgroup doesn't crash when beyond limit

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

On 2021/1/12 下午7:36, Filipe Manana wrote:
>
>
> On 12/01/21 07:40, Qu Wenruo wrote:
>> There is a bug that, when btrfs is beyond qgroup limit, touching a file
>> could crash btrfs.
>>
>> Such beyond limit situation needs to be intentionally created, e.g.
>> writing 1GiB file, then limit the subvolume to 512 MiB.
>> As current qgroup works pretty well at preventing us from reaching the
>> limit.
>>
>> This makes existing qgroup test cases unable to detect it.
>>
>> The regression is introduced by commit c53e9653605d ("btrfs: qgroup: try
>> to flush qgroup space when we get -EDQUOT"), and the fix is titled
>> "btrfs: qgroup: don't commit transaction when we have already
>>   hold a transaction handler"
>
> By the way, the patch subject changed to
>
> "btrfs: qgroup: don't commit transaction when we already hold the handle"
>
> and it's already in Linus' tree, so its commit hash should be referenced.
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6f23277a49e68f8a9355385c846939ad0b1261e7

Yeah, forgot the fix is already merged.

Hopes Eryu can handle it so I don't need to send a v3 version.

Thanks,
Qu
>
> Thanks for refreshing it.
>
>
>
>>
>> Link: https://bugzilla.suse.com/show_bug.cgi?id=1178634
>> Reviewed-by: Filipe Manana <fdmanana@suse.com>
>> Signed-off-by: Qu Wenruo <wqu@suse.com>
>> ---
>> Changelog:
>> v2:
>> - Use "0/5" to replace the double "$SCRATCH_MNT" in btrfs qgroup command
>>    To reduce confusion.
>> ---
>>   tests/btrfs/228     | 59 +++++++++++++++++++++++++++++++++++++++++++++
>>   tests/btrfs/228.out |  2 ++
>>   tests/btrfs/group   |  1 +
>>   3 files changed, 62 insertions(+)
>>   create mode 100755 tests/btrfs/228
>>   create mode 100644 tests/btrfs/228.out
>>
>> diff --git a/tests/btrfs/228 b/tests/btrfs/228
>> new file mode 100755
>> index 00000000..ecca3181
>> --- /dev/null
>> +++ b/tests/btrfs/228
>> @@ -0,0 +1,59 @@
>> +#! /bin/bash
>> +# SPDX-License-Identifier: GPL-2.0
>> +# Copyright (c) 2020 SUSE Linux Products GmbH. All Rights Reserved.
>> +#
>> +# FS QA Test 228
>> +#
>> +# Test if btrfs qgroup would crash if we're modifying the fs
>> +# after exceeding the limit
>> +#
>> +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
>> +
>> +# remove previous $seqres.full before test
>> +rm -f $seqres.full
>> +
>> +# real QA test starts here
>> +
>> +_supported_fs btrfs
>> +
>> +# Need at least 2GiB
>> +_require_scratch_size $((2 * 1024 * 1024))
>> +_scratch_mkfs > /dev/null 2>&1
>> +_scratch_mount
>> +
>> +_pwrite_byte 0xcd 0 1G $SCRATCH_MNT/file >> $seqres.full
>> +# Make sure the data reach disk so later qgroup scan can see it
>> +sync
>> +
>> +$BTRFS_UTIL_PROG quota enable $SCRATCH_MNT
>> +$BTRFS_UTIL_PROG quota rescan -w $SCRATCH_MNT >> $seqres.full
>> +
>> +# Set the limit to just 512MiB, which is way below the existing usage
>> +$BTRFS_UTIL_PROG qgroup limit  512M 0/5 $SCRATCH_MNT
>> +
>> +# Touch above file, if kernel not patched, it will trigger an ASSERT()
>> +#
>> +# Even for patched kernel, we will still get EDQUOT error, but that
>> +# is expected behavior.
>> +touch $SCRATCH_MNT/file 2>&1 | _filter_scratch
>> +
>> +# success, all done
>> +status=0
>> +exit
>> diff --git a/tests/btrfs/228.out b/tests/btrfs/228.out
>> new file mode 100644
>> index 00000000..9c250148
>> --- /dev/null
>> +++ b/tests/btrfs/228.out
>> @@ -0,0 +1,2 @@
>> +QA output created by 228
>> +touch: setting times of 'SCRATCH_MNT/file': Disk quota exceeded
>> diff --git a/tests/btrfs/group b/tests/btrfs/group
>> index 1868208e..9b0dc5ca 100644
>> --- a/tests/btrfs/group
>> +++ b/tests/btrfs/group
>> @@ -230,3 +230,4 @@
>>   225 auto quick volume seed
>>   226 auto quick rw snapshot clone prealloc punch
>>   227 auto quick send
>> +228 auto quick qgroup limit
>>