Re: [BUG 4.10-rc7] sb_fdblocks inconsistency in xfs/297 test

[Michal Hocko <mhocko@kernel.org>]

On Fri 10-02-17 08:14:18, Michal Hocko wrote:
> On Fri 10-02-17 11:53:48, Eryu Guan wrote:
> > Hi,
> > 
> > I was testing 4.10-rc7 kernel and noticed that xfs_repair reported XFS
> > corruption after fstests xfs/297 test. This didn't happen with 4.10-rc6
> > kernel, and git bisect pointed the first bad commit to
> > 
> > commit d1908f52557b3230fbd63c0429f3b4b748bf2b6d
> > Author: Michal Hocko <mhocko@suse.com>
> > Date:   Fri Feb 3 13:13:26 2017 -0800
> > 
> >     fs: break out of iomap_file_buffered_write on fatal signals
> > 
> >     Tetsuo has noticed that an OOM stress test which performs large write
> >     requests can cause the full memory reserves depletion.  He has tracked
> >     this down to the following path
> > ....
> > 
> > It's the sb_fdblocks field reports inconsistency:
> > ...
> > Phase 2 - using internal log   
> >         - zero log...
> >         - scan filesystem freespace and inode maps...
> > sb_fdblocks 3367765, counted 3367863
> >         - 11:37:41: scanning filesystem freespace - 16 of 16 allocation groups done
> >         - found root inode chunk
> > ...
> > 
> > And it can be reproduced almost 100% with all XFS test configurations
> > (e.g. xfs_4k xfs_2k_reflink), on all test hosts I tried (so I didn't
> > bother pasting my detailed test and host configs, if more info is needed
> > please let me know).
> 
> The patch can lead to short writes when the task is killed. Was there
> any OOM killer triggered during the test? If not who is killing the
> task? I will try to reproduce later today.

I have checked both tests and they are killing the test but none of them
seems to be using SIGKILL. The patch should make a difference only for
fatal signal (aka SIGKILL). Is there any other part that can do SIGKILL
except for the OOM killer?
-- 
Michal Hocko
SUSE Labs