[Gluster-users] question about info and info.tmp

Fri Nov 11 07:27:03 UTC 2016

On Fri, Nov 11, 2016 at 12:38 PM, songxin <songxin_1980 at 126.com> wrote:

>
> Hi Atin,
> Thank you for your reply.
>
> As you said that the info file can only be changed in the glusterd_store_volinfo()
> sequentially because of the big lock.
>
> I have found the similar issue as below that you mentioned.
> https://bugzilla.redhat.com/show_bug.cgi?id=1308487
>

Great, so this is what I was actually trying to refer in my first email
that I saw a similar issue. Have you got a chance to look at
https://bugzilla.redhat.com/show_bug.cgi?id=1308487#c4 ? But in your case,
did you try to bring down glusterd when there was an ongoing commit
happening?

>
> You said that "This issue is hit at part of the negative testing where
> while gluster volume set was executed at the same point of time glusterd in
> another instance was brought down. In the faulty node we could see
> /var/lib/glusterd/vols/<volname>info file been empty whereas the info.tmp
> file has the correct contents." in comment.
>
> I have two questions for you.
>
> 1.Could you reproduce this issue by gluster volume set glusterd which was brought down?
> 2.Could you be certain that this issue is cause by rename is interrupted in kernel?
>
> In my case there are two files, info and 10.32.1.144.-opt-lvmdir-c2-brick, are both empty.
> But in my view only one rename can be running at the same time because of the big lock.
> Why there are two files are empty?
>
>
> Could rename("info.tmp", "info") and rename("xxx-brick.tmp", "xxx-brick") be running in two thread?
>
> Thanks,
> Xin
>
>
>
>
> 在 2016-11-11 14:36:40，"Atin Mukherjee" <amukherj at redhat.com> 写道：
>
>
>
> On Fri, Nov 11, 2016 at 8:33 AM, songxin <songxin_1980 at 126.com> wrote:
>
>> Hi Atin,
>>
>> Thank you for your reply.
>> I have two questions for you.
>>
>> 1.Are the two files info and info.tmp are only to be created or changed
>> in function glusterd_store_volinfo()? I did not find other point in which
>> the two file are changed.
>>
>
> If we are talking about info file volume then yes, the mentioned function
> actually takes care of it.
>
>
>> 2.I found that glusterd_store_volinfo() will be call in many point by
>> glusterd.Is there a problem of thread synchronization?If so, one thread may
>> open a same file info.tmp using O_TRUNC flag when another thread is
>> writing the info,tmp.Could this case happen?
>>
>
>  In glusterd threads are big lock protected and I don't see a possibility
> (theoretically) to have two glusterd_store_volinfo () calls at a given
> point of time.
>
>
>>
>> Thanks,
>> Xin
>>
>>
>> At 2016-11-10 21:41:06, "Atin Mukherjee" <amukherj at redhat.com> wrote:
>>
>> Did you run out of disk space by any chance? AFAIK, the code is like we
>> write new stuffs to .tmp file and rename it back to the original file. In
>> case of a disk space issue I expect both the files to be of non zero size.
>> But having said that I vaguely remember a similar issue (in the form of a
>> bug or an email) landed up once but we couldn't reproduce it, so something
>> is wrong with the atomic update here is what I guess. I'll be glad if you
>> have a reproducer for the same and then we can dig into it further.
>>
>> On Thu, Nov 10, 2016 at 1:32 PM, songxin <songxin_1980 at 126.com> wrote:
>>
>>> Hi,
>>> When I start the glusterd some error happened.
>>> And the log is following.
>>>
>>> [2016-11-08 07:58:34.989365] I [MSGID: 100030] [glusterfsd.c:2318:main]
>>> 0-/usr/sbin/glusterd: Started running /usr/sbin/glusterd version 3.7.6
>>> (args: /usr/sbin/glusterd -p /var/run/glusterd.pid --log-level INFO)
>>> [2016-11-08 07:58:34.998356] I [MSGID: 106478] [glusterd.c:1350:init]
>>> 0-management: Maximum allowed open file descriptors set to 65536
>>> [2016-11-08 07:58:35.000667] I [MSGID: 106479] [glusterd.c:1399:init]
>>> 0-management: Using /system/glusterd as working directory
>>> [2016-11-08 07:58:35.024508] I [MSGID: 106514]
>>> [glusterd-store.c:2075:glusterd_restore_op_version] 0-management:
>>> Upgrade detected. Setting op-version to minimum : 1
>>> *[2016-11-08 07:58:35.025356] E [MSGID: 106206]
>>> [glusterd-store.c:2562:glusterd_store_update_volinfo] 0-management: Failed
>>> to get next store iter *
>>> *[2016-11-08 07:58:35.025401] E [MSGID: 106207]
>>> [glusterd-store.c:2844:glusterd_store_retrieve_volume] 0-management: Failed
>>> to update volinfo for c_glusterfs volume *
>>> *[2016-11-08 07:58:35.025463] E [MSGID: 106201]
>>> [glusterd-store.c:3042:glusterd_store_retrieve_volumes] 0-management:
>>> Unable to restore volume: c_glusterfs *
>>> *[2016-11-08 07:58:35.025544] E [MSGID: 101019]
>>> [xlator.c:428:xlator_init] 0-management: Initialization of volume
>>> 'management' failed, review your volfile again *
>>> *[2016-11-08 07:58:35.025582] E [graph.c:322:glusterfs_graph_init]
>>> 0-management: initializing translator failed *
>>> *[2016-11-08 07:58:35.025629] E [graph.c:661:glusterfs_graph_activate]
>>> 0-graph: init failed *
>>> [2016-11-08 07:58:35.026109] W [glusterfsd.c:1236:cleanup_and_exit]
>>> (-->/usr/sbin/glusterd(glusterfs_volumes_init-0x1b260) [0x1000a718]
>>> -->/usr/sbin/glusterd(glusterfs_process_volfp-0x1b3b8) [0x1000a5a8]
>>> -->/usr/sbin/glusterd(cleanup_and_exit-0x1c02c) [0x100098bc] ) 0-:
>>> received signum (0), shutting down
>>>
>>>
>>> And then I found that the size of vols/volume_name/info is 0.It cause
>>> glusterd shutdown.
>>> But I found that vols/volume_name_info.tmp is not 0.
>>> And I found that there is a brick file vols/volume_name/bricks/xxxx.brick
>>> is 0, but vols/volume_name/bricks/xxxx.brick.tmp is not 0.
>>>
>>> I read the function code glusterd_store_volinfo () in glusterd-store.c .
>>> I know that the info.tmp will be rename to info in function
>>> glusterd_store_volume_atomic_update().
>>>
>>> But my question is that why the info file is 0 but info.tmp is not 0.
>>>
>>>
>>> Thanks,
>>> Xin
>>>
>>>
>>>
>>>
>>> _______________________________________________
>>> Gluster-users mailing list
>>> Gluster-users at gluster.org
>>> http://www.gluster.org/mailman/listinfo/gluster-users
>>>
>>
>>
>>
>> --
>>
>> ~ Atin (atinm)
>>
>>
>>
>>
>>
>
>
>
> --
>
> ~ Atin (atinm)
>
>
>
>
>

-- 

~ Atin (atinm)
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