Re: [PATCH v2] xfs/133,4: make sure xfs_db sets negative i_size

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

On 2017/02/22 18:49, Eryu Guan wrote:
> On Wed, Feb 22, 2017 at 05:31:40PM +0800, Xiao Yang wrote:
>> 1) xfs/133 and xfs/134 work abnornamlly on RHEL6.8GA and RHEL6.9Beta
>>     because xfs_db fails to set i_size to -1 or -512 and reports "usage:
>>     write fieldname value".  The special argument "--" is only used to
>>     end option-scanning in getopt().  So we should add "--" for write
>>     command in xfs_db when -c option is supported by write command.
>>     getopt() has been produced by 'commit c9f5e3db22098 ("xfs_db: Allow
>>     writes of corrupted data")'.
>>
>> 2) When xfs_db fails to set a negative i_size due to unknown error, we
>>     can skip these cases which don't trigger the kernel bug.
>>
>> Signed-off-by: Xiao Yang<yangx.jy@cn.fujitsu.com>
> Sorry for the late review on this patch. I just got some time to look at
> xfs/133,4 a bit closely.
>
> It turns out that the EINVAL error you saw is because of
>
> echo m>  $testdir/a
>
> and direct append failed because the write offset is not 512-aligned.
>
> Just "touch $testdir/a" should work (you can see test failure on RHEL6.8
> with current master).
>
Hi Eryu

I saw test failure on RHEL6.8 occasionally when using touch command to 
create file. :-)
I will rewrite this patch as you suggestions.

Best Regards,
Xiao Yang
>> ---
>>   tests/xfs/133 | 13 ++++++++++++-
>>   tests/xfs/134 | 17 ++++++++++++++---
>>   2 files changed, 26 insertions(+), 4 deletions(-)
>>
>> diff --git a/tests/xfs/133 b/tests/xfs/133
>> index d756d2e..91b3b9b 100755
>> --- a/tests/xfs/133
>> +++ b/tests/xfs/133
>> @@ -63,7 +63,18 @@ inum=$(stat -c "%i" $testdir/a)
>>
>>   echo "Corrupt filesystem"
>>   _scratch_unmount
>> -_scratch_xfs_db -x -c "inode ${inum}" -c 'write core.size -- -1'>>  $seqres.full
>> +
>> +# 1) we should add "--" for write command in xfs_db when -c option is
>> +#    supported by write command.
>> +# 2) check whether xfs_db succeeds to set i_size to -1 or not
>> +_scratch_xfs_db -x -c "help" | grep -q "write \[-c\]"
>> +if [ $? -eq 0 ]; then
>> +	_scratch_xfs_db -x -c "inode ${inum}" -c 'write core.size -- -1'>>  $seqres.full 2>&1 || \
>> +	_notrun "Could not set i_size to -1 successfully, skip test."
>> +else
>> +	_scratch_xfs_db -x -c "inode ${inum}" -c 'write core.size -1'>>  $seqres.full 2>&1 || \
>> +	_notrun "Could not set i_size to -1 successfully, skip test."
>> +fi
> This check looks tedious, and xfs_db doesn't return non-zero on error,
> so this will never _notrun.
>
> I'd suggest running the two xfs_db commands unconditionally (with clear
> comments), there has to be one suitable call for the xfs_db version in
> use, and check core.size is -1/-512 by printing it with xfs_db. e.g.
>
> #<comments about these two calls>
> _scratch_xfs_db -x -c "inode ${inum}" -c "write core.size -1">>$seqres.full 2>&1
> _scratch_xfs_db -x -c "inode ${inum}" -c "write core.size -- -1">>$seqres.full 2>&1
>
> # check core.size and _notrun if it's not set correctly
> isize=`_scratch_xfs_db -c "inode ${inum}" -c "print core.size" | $AWK_PROG '{print $3}'`
> if [ $isize -ne -1 ]; then
> 	_notrun "..."
> fi
> Thanks,
> Eryu
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