Re: [PATCH 1/2] ext4: check mount's handling for very large s_first_meta_bg

[Xiao Yang <yangx.jy@cn.fujitsu.com>]

On 2017/04/24 16:43, Eryu Guan wrote:
> On Mon, Apr 24, 2017 at 01:52:26PM +0800, Xiao Yang wrote:
>
>>>> +_require_command "$DEBUGFS_PROG" debugfs
>>>> +_require_ext4_mkfs_feature "bigalloc,meta_bg,^resize_inode"
>>>> +
>>>> +echo "Create ext4 fs and modify first_meta_bg's value"
>>>> +$MKFS_EXT4_PROG -F -b 4096 -O bigalloc,meta_bg,^resize_inode $SCRATCH_DEV 16m>>   $seqres.full 2>&1 \
>>>> +	|| _notrun "Could not create ext4 filesystem"
>>> _scratch_mkfs "-O bigalloc,meta_bg,^resize_inode">>   $seqres.full 2>&1
>>>
>>> should be fine, if there're conflicts between MKFS_OPTIONS and these
>>> extra mkfs options _scratch_mkfs will mkfs again only with test-provided
>>> mkfs options.
>>>
>> I will use _scratch_mkfs as you said.  However, i still specify 4096 as
>> block size, because debugfs can't set first_meta_bg
>> to 842150400 on RHEL7 when default block size is 1024.   Please see the
>> following e2fsprogs bug:
>>
>> commit d36b957b345ee6e4b529be99b8fdc8d3e70ccdc1
>> Author: Darrick J. Wong<darrick.wong@oracle.com>
>> Date:   Sat Jan 11 13:58:15 2014 -0500
>>
>>      libext2fs: don't always read backup group descriptors on a 1k-block
>> meta_bg fs
> I noticed this too, debugfs failed to open ext4 fs when block size is 1k
> when testing on my rhel7 host. But I think what should be done is fixing
> e2fsprogs on RHEL7 not workarounding the bug in the test code. The test
> is doing nothing wrong, and it 'finds' a bug (test not run).
>
> This leads me to wonder if we should skip this test if debugfs hanppened
> to fail to set first_meta_bg? So that test would fail explicitly (mount
> succeeds unexpectedly) instead of _notrun and being ignored.
>
Hi Eryu

Agreed, we should indicate various bugs instead of ignoring  them, so i 
will send v3 patch.
Thanks for your comment. :-)

Thanks,
Xiao Yang
> Thanks,
> Eryu
>
>
>