Re: [PATCH 1/3] btrfs/012 btrfs/136: skip the test if ext* doesn't support the block size

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

在 2025/10/2 06:20, Zorro Lang 写道:
> On Mon, Sep 29, 2025 at 06:12:17AM +0930, Qu Wenruo wrote:
>>
>>
>> 在 2025/9/29 00:24, Zorro Lang 写道:
>>> On Fri, Sep 19, 2025 at 08:13:25AM +0930, Qu Wenruo wrote:
>>>> [FALSE ALERT]
>>>> When testing btrfs bs > ps support, the test cases btrfs/012 and
>>>> btrfs/136 fail like the following:
>>>>
>>>>    FSTYP         -- btrfs
>>>>    PLATFORM      -- Linux/x86_64 btrfs-vm 6.17.0-rc4-custom+ #285 SMP PREEMPT_DYNAMIC Mon Sep 15 14:40:01 ACST 2025
>>>>    MKFS_OPTIONS  -- -s 8k /dev/mapper/test-scratch1
>>>>    MOUNT_OPTIONS -- /dev/mapper/test-scratch1 /mnt/scratch
>>>>
>>>>    btrfs/012       [failed, exit status 1]- output mismatch (see /home/adam/xfstests/results//btrfs/012.out.bad)
>>>>        --- tests/btrfs/012.out	2024-07-17 16:27:18.790000343 +0930
>>>>        +++ /home/adam/xfstests/results//btrfs/012.out.bad	2025-09-15 16:32:55.185922173 +0930
>>>>        @@ -1,7 +1,11 @@
>>>>         QA output created by 012
>>>>        +mount: /mnt/scratch: wrong fs type, bad option, bad superblock on /dev/mapper/test-scratch1, missing codepage or helper program, or other error.
>>>>        +       dmesg(1) may have more information after failed mount system call.
>>>>        +mkdir: cannot create directory '/mnt/scratch/stressdir': File exists
>>>>        +umount: /mnt/scratch: not mounted.
>>>>         Checking converted btrfs against the original one:
>>>>        -OK
>>>>        ...
>>>>        (Run 'diff -u /home/adam/xfstests/tests/btrfs/012.out /home/adam/xfstests/results//btrfs/012.out.bad'  to see the entire diff)
>>>>
>>>>    btrfs/136 3s ... - output mismatch (see /home/adam/xfstests/results//btrfs/136.out.bad)
>>>>        --- tests/btrfs/136.out	2022-05-11 11:25:30.743333331 +0930
>>>>        +++ /home/adam/xfstests/results//btrfs/136.out.bad	2025-09-19 07:00:00.395280850 +0930
>>>>        @@ -1,2 +1,10 @@
>>>>         QA output created by 136
>>>>        +mount: /mnt/scratch: wrong fs type, bad option, bad superblock on /dev/mapper/test-scratch1, missing codepage or helper program, or other error.
>>>>        +       dmesg(1) may have more information after failed mount system call.
>>>>        +umount: /mnt/scratch: not mounted.
>>>>        +mount: /mnt/scratch: wrong fs type, bad option, bad superblock on /dev/mapper/test-scratch1, missing codepage or helper program, or other error.
>>>>        +       dmesg(1) may have more information after failed mount system call.
>>>>        +umount: /mnt/scratch: not mounted.
>>>>        ...
>>>>        (Run 'diff -u /home/adam/xfstests/tests/btrfs/136.out /home/adam/xfstests/results//btrfs/136.out.bad'  to see the entire diff)
>>>>
>>>> [CAUSE]
>>>> Currently ext* doesn't support block size larger than page size, thus
>>>> at mkfs time it will output the following warning:
>>>>
>>>>    Warning: blocksize 8192 not usable on most systems.
>>>>    mke2fs 1.47.3 (8-Jul-2025)
>>>>    Warning: 8192-byte blocks too big for system (max 4096), forced to continue
>>>>
>>>> Furthermore at ext* mount time it will fail with the following dmesg:
>>>>
>>>>    EXT4-fs (loop0): bad block size 8192
>>>>
>>>> [FIX]
>>>> Check if the mount of the newly created ext* succeeded.
>>>>
>>>> If not, since the only extra parameter for mkfs is the block size, we
>>>> know it's some block size ext* not yet supported, and skip the test
>>>> case.
>>>>
>>>> Signed-off-by: Qu Wenruo <wqu@suse.com>
>>>> ---
>>>>    tests/btrfs/012 | 3 +++
>>>>    tests/btrfs/136 | 3 +++
>>>>    2 files changed, 6 insertions(+)
>>>>
>>>> diff --git a/tests/btrfs/012 b/tests/btrfs/012
>>>> index f41d7e4e..665831b9 100755
>>>> --- a/tests/btrfs/012
>>>> +++ b/tests/btrfs/012
>>>> @@ -42,6 +42,9 @@ $MKFS_EXT4_PROG -F -b $BLOCK_SIZE $SCRATCH_DEV > $seqres.full 2>&1 || \
>>>>    	_notrun "Could not create ext4 filesystem"
>>>>    # Manual mount so we don't use -t btrfs or selinux context
>>>>    mount -t ext4 $SCRATCH_DEV $SCRATCH_MNT
>>>> +if [ $? -ne 0 ]; then
>>>> +	_notrun "block size $BLOCK_SIZE is not supported by ext4"
>>>> +fi
>>>
>>> Hmm... the mount failure maybe not caused by the "$BLOCK_SIZE is not supported",
>>> I'm wondering if this _notrun might ignore real bug. How about check the
>>> "blocksize < pagesize" at least?
>>
>> The only extra parameter passed to mkfs.ext* is "-b $BLOCKSIZE", and if it's
>> really some bug inside e2fsprog and it only affects bs > ps, we're still
>> going to miss the bug.
>>
>> Is there any proper way to reliably check the supported block size of ext*?
>> Like some sysfs knobs?
> 
> If there's not a proper way to check ext4 supports LBS, how about check
> blocksize < pagesize" before _notrun directly, e.g:
> 
>    pz=$(_get_page_size)
>    if [ $? -ne 0 -a $BLOCKSIZE -gt $pz ]

OK, I'll just add the manual block size check.

Thanks,
Qu

> 
> Thanks,
> Zorro
> 
>>
>> Thanks,
>> Qu
>>
>>>
>>>>    echo "populating the initial ext fs:" >> $seqres.full
>>>>    mkdir "$SCRATCH_MNT/$BASENAME"
>>>> diff --git a/tests/btrfs/136 b/tests/btrfs/136
>>>> index 65bbcf51..6b4b52e4 100755
>>>> --- a/tests/btrfs/136
>>>> +++ b/tests/btrfs/136
>>>> @@ -45,6 +45,9 @@ $MKFS_EXT4_PROG -F -t ext3 -b $BLOCK_SIZE $SCRATCH_DEV > $seqres.full 2>&1 || \
>>>>    # mount and populate non-extent file
>>>>    mount -t ext3 $SCRATCH_DEV $SCRATCH_MNT
>>>> +if [ $? -ne 0 ]; then
>>>> +	_notrun "block size $BLOCK_SIZE is not supported by ext3"
>>>> +fi
>>>>    populate_data "$SCRATCH_MNT/ext3_ext4_data/ext3"
>>>>    _scratch_unmount
>>>> -- 
>>>> 2.51.0
>>>>
>>>>
>>>
>>>
>>
>