[Trusty] Hang and corruption in dcache_shrink_list

[Dave Chiluk]

I was able to successfully run the xfstests to completion without a hang
or crash, and I was also able to run the script described in
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1354157
without issue as well.  However, I was unable to induce the crash with
that script earlier.  However, the user has reported to me as well that
the above fixes have resolved their issues.

So rtg, I think you are good to go ahead and pull those fixes.

Dave Chiluk



On 08/15/2014 08:42 AM, Tim Gardner wrote:
> Dave - if you would log the type and results of your testing in the bug
> report, I'd be willing to apply this patch set. It looks like these
> patches will solve at least 2 reporters problems.
> 
> rtg
> 
> 
> On 08/14/2014 12:58 PM, Dave Chiluk wrote:
>> I did some more review of the recent dcache changes that have gone in
>> upstream, and I think it's appropriate for us to bring those in as well.
>>
>> I hope pushed my branch 70318 to
>> http://kernel.ubuntu.com/git?p=chiluk/ubuntu-trusty.git;a=shortlog;h=refs/heads/70318
>> for review.
>>
>> Basically I included all upstream patches related to locking (or their
>> requisite code cleanup patches) that pertain to dcache_shrink_list.
>>
>> Dave.
>>
>> On 08/12/2014 08:59 AM, Tim Gardner wrote:
>>> On 08/08/2014 12:18 PM, Dave Chiluk wrote:
>>>> BugLink: http://bugs.launchpad.net/bugs/1354157
>>>>
>>>> The patchset described here and committed to upstream
>>>> https://lkml.org/lkml/2014/5/4/7
>>>> can be cleanly cherry-picked, and has been applied to
>>>> git://kernel.ubuntu.com/chiluk/ubuntu-trusty.git branch 70318
>>>> The end user reports that the above patch set fixes the issue.
>>>>
>>>> I'd like to get some additional review on this patchset before
>>>> submitting it for actual inclusion.
>>>>
>>>> That all being said, I think we should strongly consider pulling in
>>>> 046b961b4
>>>> b2b80195d
>>>> 9f12600fe
>>>> and b2b80195d88
>>>> as well, as these look to be more related to a possible lock starvation
>>>> case.
>>>>
>>>> Open for discussion.
>>>> Dave.
>>>>
>>>
>>> I did an identical patch set for a different bug
>>> (http://bugs.launchpad.net/bugs/1354234). Shall we dup them ?
>>>
>>> The following changes since commit 0a0caf5157bffb6340de804b3a8c94e045f68fb7:
>>>
>>>   ahci_xgene: Use correct OOB tunning parameters for APM X-Gene SoC AHCI
>>> SATA Host controller driver. (2014-08-12 06:40:52 -0600)
>>>
>>> are available in the git repository at:
>>>
>>>   git://kernel.ubuntu.com/rtg/ubuntu-trusty.git
>>> lp1354234-dcache-shrink-list-corruption
>>>
>>> for you to fetch changes up to 3b1cbde08418dbd8cc2d819b9e7412303818deba:
>>>
>>>   dcache: don't need rcu in shrink_dentry_list() (2014-08-12 07:47:39 -0600)
>>>
>>> ----------------------------------------------------------------
>>> Al Viro (7):
>>>       fold d_kill() and d_free()
>>>       fold try_prune_one_dentry()
>>>       new helper: dentry_free()
>>>       expand the call of dentry_lru_del() in dentry_kill()
>>>       dentry_kill(): don't try to remove from shrink list
>>>       don't remove from shrink list in select_collect()
>>>       more graceful recovery in umount_collect()
>>>
>>> Miklos Szeredi (1):
>>>       dcache: don't need rcu in shrink_dentry_list()
>>>
>>>  fs/dcache.c            | 315
>>> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>>>  include/linux/dcache.h |   2 ++
>>>  2 files changed, 103 insertions(+), 214 deletions(-)
>>>
>>>
>>
>>
> 
>