oops from deliberate block trashing (of course!)

[Michael L. Semon]

On 03/28/2013 02:14 AM, Dave Chinner wrote:
> On Thu, Mar 28, 2013 at 01:18:24AM -0400, Michael L. Semon wrote:
>> ==== SECOND OOPS: xfs_db blocktrash test
>>
>> root at oldsvrhw:~# xfs_db -x /dev/sdb2
>> xfs_db> blockget
>> xfs_db> blocktrash -n 10240 -s 755366564 -3 -x 1 -y 16
>> blocktrash: 0/17856 inode block 6 bits starting 423:0 randomized
>> [lots of blocktrash stuff removed but still available]
>> blocktrash: 3/25387 dir block 2 bits starting 1999:1 randomized
>> xfs_db> quit
>> root at oldsvrhw:~# mount /dev/sdb2 /mnt/hole-test/
>> root at oldsvrhw:~# cd /mnt/hole-test/
>> root at oldsvrhw:/mnt/hole-test# find . -type f
>>
>> XFS (sdb2): Mounting Filesystem
>> XFS (sdb2): Ending clean mount
>> XFS (sdb2): Invalid inode number 0x40000000800084
>> XFS (sdb2): Internal error xfs_dir_ino_validate at line 160 of file
>> fs/xfs/xfs_dir2.c.  Caller 0xc12b9d0d
>>
>> Pid: 97, comm: kworker/0:1H Not tainted 3.9.0-rc1+ #1
>> Call Trace:
>>   [<c1270cbb>] xfs_error_report+0x4b/0x50
>>   [<c12b9d0d>] ? __xfs_dir3_data_check+0x3cd/0x710
>>   [<c12b6326>] xfs_dir_ino_validate+0xb6/0x180
>>   [<c12b9d0d>] ? __xfs_dir3_data_check+0x3cd/0x710
>>   [<c12b9d0d>] __xfs_dir3_data_check+0x3cd/0x710
>>   [<c105ffe8>] ? update_curr.constprop.41+0xa8/0x180
>>   [<c12b7289>] xfs_dir3_block_verify+0x89/0xa0
>
> And here we validating a different directory block, and finding that
> the inode number it points to is invalid. So, same thing - debug
> kernel fires an assert, production kernel returns EFSCORRUPTED.
>
> What you are seeing is that the verifiers are doing their job as
> intended - catching corruption that is on disk as soon as we
> possibly can. i.e. before it has the chance of being propagated
> further.
>
> Cheers,
>
> Dave.

Very good!  It's good to learn that all of those verifiers are doing 
their jobs...that the ASSERTs all have some kind of dedicated 
purpose...and that I shouldn't face this in non-debug mode.

These proof-positve crash reports are excellent.  I just wish I knew how 
to make them on purpose.

Thanks again, Dave.

Michael