[Ocfs2-devel] [PATCH 1/2] ocfs2: dlmfs: not clear USER_LOCK_ATTACHED when destroy lock

[Junxiao Bi]

On 5/16/22 6:58 PM, Joseph Qi wrote:
>
> On 5/17/22 12:30 AM, Junxiao Bi wrote:
>> On 5/15/22 7:57 AM, Joseph Qi wrote:
>>> On 5/14/22 12:27 AM, Junxiao Bi wrote:
>>>> On 5/12/22 7:05 PM, Joseph Qi wrote:
>>>>
>>>>> On 5/11/22 7:22 AM, Junxiao Bi wrote:
>>>>>> The following function is the only place that check USER_LOCK_ATTACHED,
>>>>>> this flag is set when lock request is granted through user_bast() and
>>>>>> only the following function will clear it.
>>>>>>
>>>>> user_ast?
>>>> Good catch, that's a typo, should be user_ast.
>>>>>> Checking of this flag here is to make sure ocfs2_dlm_unlock is not
>>>>>> issued if this lock is never granted. For example, lock file is created
>>>>>> and then get removed, open file never happens.
>>>>>>
>>>>>> Clearing the flag here is not necessary because this is the only function
>>>>>> that checks it, if another flow is executing user_dlm_destroy_lock(), it
>>>>>> will bail out at the beginning because of USER_LOCK_IN_TEARDOWN and never
>>>>>> check USER_LOCK_ATTACHED.
>>>>>> Drop the clear, so we don't need take care it for the following
>>>>>> error handling patch.
>>>>>>
>>>>> Seems it depends on initializing lockres every time, but it seems this
>>>>> is not true for directory now.
>>>> Sorry, i didn't get this. Can you elaborate this?
>>>>
>>> lockres may be reused and if we don't reinitialized, the left flag can
>>> cause unexpected behavior.
>> I don't know how it could get reused since it's going to be removed. Anyway USER_LOCK_IN_TEARDOWN is still set in lockres. All the flow will bail out because of this flag.
>>
> dlmfs_inode_private is allocated from kmem_cache.
> The case I'm thinking about is, calling user_dlm_destroy_lock() without
> a valid ast comming before. So checking USER_LOCK_ATTACHED here may be
> incorrect.
> But look more closer, it seems that lockres is unused for directories.
> So it won't be a real issue.
Yes, lock is only for file, not direcotry.
> Could you please send a new version with update description?

Sorry, little confused, which part of description needs update?

Thanks,

Junxiao.

>
> Thanks,
> Joseph