[Ocfs2-devel] [Question] deadlock on chmod when running discontigous block group multiple node testing

[Eric Ren]

Hi Junxiao,

On 10/12/2016 02:47 PM, Junxiao Bi wrote:
> On 10/12/2016 10:36 AM, Eric Ren wrote:
>> Hi,
>>
>> When backporting those patches, I find that they are already in our
>> product kernel, maybe
>> via "stable kernel" policy, although our product kernel is 4.4 while the
>> patches were merged
>> into 4.6.
>>
>> Seems it's another deadlock that happens when doing `chmod -R 777
>> /mnt/ocfs2`
>> among mutilple nodes at the same time.
> Yes, but i just finish running ocfs2 full test on linux next-20161006
> and didn't find any issue.

Thanks a lot, really!

1. What's the size of your ocfs2 disk? My disk is 200G.

2. Did you run discontig block group test with multiple nodes? with this option:

                 " -m ocfs2cts1,ocfs2cts2"

3. Then, I am using fs/dlm. That's a different point.

Thanks,
Eric

>
> Thanks,
> Junxiao.
>
>> Thanks,
>> Eric
>> On 10/12/2016 09:23 AM, Eric Ren wrote:
>>> Hi Junxiao,
>>>
>>>> Hi Eric,
>>>>
>>>> On 10/11/2016 10:42 AM, Eric Ren wrote:
>>>>> Hi Junxiao,
>>>>>
>>>>> As the subject, the testing hung there on a kernel without your
>>>>> patches:
>>>>>
>>>>> "ocfs2: revert using ocfs2_acl_chmod to avoid inode cluster lock hang"
>>>>> and
>>>>> "ocfs2: fix posix_acl_create deadlock"
>>>>>
>>>>> The stack trace is:
>>>>> ```
>>>>> ocfs2cts1:~ # pstree -pl 24133
>>>>> discontig_runne(24133)───activate_discon(21156)───mpirun(15146)─┬─fillup_contig_b(15149)───sudo(15231)───chmod(15232)
>>>>>
>>>>>
>>>>> ocfs2cts1:~ # pgrep -a chmod
>>>>> 15232 /bin/chmod -R 777 /mnt/ocfs2
>>>>>
>>>>> ocfs2cts1:~ # cat /proc/15232/stack
>>>>> [<ffffffffa05377ef>] __ocfs2_cluster_lock.isra.39+0x1bf/0x620 [ocfs2]
>>>>> [<ffffffffa053856d>] ocfs2_inode_lock_full_nested+0x12d/0x840 [ocfs2]
>>>>> [<ffffffffa0538dbb>] ocfs2_inode_lock_atime+0xcb/0x170 [ocfs2]
>>>>> [<ffffffffa0531e61>] ocfs2_readdir+0x41/0x1b0 [ocfs2]
>>>>> [<ffffffff8120d03c>] iterate_dir+0x9c/0x110
>>>>> [<ffffffff8120d453>] SyS_getdents+0x83/0xf0
>>>>> [<ffffffff815e126e>] entry_SYSCALL_64_fastpath+0x12/0x6d
>>>>> [<ffffffffffffffff>] 0xffffffffffffffff
>>>>> ```
>>>>>
>>>>> Do you think this issue can be fixed by your patches?
>>>> Looks not. Those two patches are to fix recursive locking deadlock. But
>>>> from above call trace, there is no recursive lock.
>>> Sorry, the call trace on another node was missing.  Here it is:
>>>
>>> ocfs2cts2:~ # pstree -lp
>>> sshd(4292)─┬─sshd(4745)───sshd(4753)───bash(4754)───orted(4781)───fillup_contig_b(4782)───sudo(4864)───chmod(4865)
>>>
>>>
>>> ocfs2cts2:~ # cat /proc/4865/stack
>>> [<ffffffffa053e7ef>] __ocfs2_cluster_lock.isra.39+0x1bf/0x620 [ocfs2]
>>> [<ffffffffa053f56d>] ocfs2_inode_lock_full_nested+0x12d/0x840 [ocfs2]
>>> [<ffffffffa059c860>] ocfs2_iop_get_acl+0x40/0xf0 [ocfs2]
>>> [<ffffffff812044e6>] generic_permission+0x166/0x1c0
>>> [<ffffffffa0542aca>] ocfs2_permission+0xaa/0xd0 [ocfs2]
>>> [<ffffffff81204596>] __inode_permission+0x56/0xb0
>>> [<ffffffff812068fa>] link_path_walk+0x29a/0x560
>>> [<ffffffff81206cbf>] path_lookupat+0x7f/0x110
>>> [<ffffffff8120929c>] filename_lookup+0x9c/0x150
>>> [<ffffffff811f96c3>] SyS_fchmodat+0x33/0x90
>>> [<ffffffff815e126e>] entry_SYSCALL_64_fastpath+0x12/0x6d
>>> [<ffffffffffffffff>] 0xffffffffffffffff
>>>
>>> Thanks,
>>> Eric
>>>
>>>
>>>> Thanks,
>>>> Junxiao.
>>>>> I will try your patches later, but I am little worried the possibility
>>>>> of reproduction may not be 100%.
>>>>> So ask you to confirm;-)
>>>>>
>>>>> Eric
>>> _______________________________________________
>>> Ocfs2-devel mailing list
>>> Ocfs2-devel at oss.oracle.com
>>> https://oss.oracle.com/mailman/listinfo/ocfs2-devel
>>
>