Re: [PATCH 0/8] Fixup uninitialized warnings and enable extra checks

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

On 2022/12/17 07:55, Qu Wenruo wrote:
> 
> 
> On 2022/12/17 04:15, Josef Bacik wrote:
>> Hello,
>>
>> We had been failing the raid56 related scrub tests on our overnight 
>> tests since
>> November.  Initially I asked Qu to look into these as I didn't have 
>> time to dig
>> in, and he was unable to reproduce.  I assumed it was some oddity in 
>> my setup,
>> so I ignored it.  However recently I got a report that I regressed 
>> some of these
>> tests with an unrelated change.  When debugging it I found it was 
>> because of an
>> uninitialized return value, which would have been caught by more 
>> modern gcc's
>> with -Wmaybe-uninitialized.
> 
> Any clue which patch is fixing the raid0/raid1 scrub failures?
> 
> As locally, I found my aarch64/x86_64 VMs are all reporting scrub errors 
> for all profiles, including RAID0/RAID1.
> (The failure happens after patch "btrfs: do not check header generation 
> in btrfs_clean_tree_block").
> 
> I didn't notice any of the patches touching the scrub path, or is there 
> some hidden paths involved?

In fact, it's still reproducible reliably here, with all uninitialized 
fixes applied upon "btrfs: do not check header generation in 
btrfs_clean_tree_block".


btrfs/072 30s ... - output mismatch (see 
/home/adam/xfstests/results//btrfs/072.out.bad)
     --- tests/btrfs/072.out	2022-05-11 09:55:30.736666664 +0800
     +++ /home/adam/xfstests/results//btrfs/072.out.bad	2022-12-17 
08:05:26.750000015 +0800
     @@ -1,2 +1,9 @@
      QA output created by 072
      Silence is golden
     +Scrub find errors in "-m dup -d single" test
     +Scrub find errors in "-m raid0 -d raid0" test
     +Scrub find errors in "-m raid0 -d raid0" test
     +Scrub find errors in "-m raid1 -d raid0" test
     +Scrub find errors in "-m raid10 -d raid10" test
     ...
     (Run 'diff -u /home/adam/xfstests/tests/btrfs/072.out 
/home/adam/xfstests/results//btrfs/072.out.bad'  to see the entire diff)
btrfs/074 32s ... - output mismatch (see 
/home/adam/xfstests/results//btrfs/074.out.bad)
     --- tests/btrfs/074.out	2022-05-11 09:55:30.736666664 +0800
     +++ /home/adam/xfstests/results//btrfs/074.out.bad	2022-12-17 
08:06:00.036666681 +0800
     @@ -1,2 +1,3 @@
      QA output created by 074
      Silence is golden
     +Scrub find errors in "-m raid1 -d raid1" test
     ...
     (Run 'diff -u /home/adam/xfstests/tests/btrfs/074.out 
/home/adam/xfstests/results//btrfs/074.out.bad'  to see the entire diff)
Ran: btrfs/072 btrfs/074
Failures: btrfs/072 btrfs/074

Thanks,
Qu

> 
> Thanks,
> Qu
> 
>>
>> In order to avoid these sort of problems in the future lets fix up all 
>> the false
>> positivies that this warning brings, and then enable the option for 
>> btrfs so we
>> can avoid this style of failure in the future.  Thanks,
>>
>> Josef
>>
>> Josef Bacik (8):
>>    btrfs: fix uninit warning in run_one_async_start
>>    btrfs: fix uninit warning in btrfs_cleanup_ordered_extents
>>    btrfs: fix uninit warning from get_inode_gen usage
>>    btrfs: fix uninit warning in btrfs_update_block_group
>>    btrfs: fix uninit warning in __set_extent_bit and convert_extent_bit
>>    btrfs: extract out zone cache usage into it's own helper
>>    btrfs: fix uninit warning in btrfs_sb_log_location
>>    btrfs: turn on -Wmaybe-uninitialized
>>
>>   fs/btrfs/Makefile         |  1 +
>>   fs/btrfs/block-group.c    |  2 +-
>>   fs/btrfs/disk-io.c        |  2 +-
>>   fs/btrfs/extent-io-tree.c |  8 ++---
>>   fs/btrfs/inode.c          |  2 +-
>>   fs/btrfs/send.c           |  8 ++---
>>   fs/btrfs/zoned.c          | 75 ++++++++++++++++++++++++---------------
>>   7 files changed, 57 insertions(+), 41 deletions(-)
>>