[Ocfs2-devel] [PATCH] ocfs2/dlm: return DLM_CANCELGRANT if the lock is on granted list and the operation is canceled
piaojun
piaojun at huawei.com
Mon Feb 18 16:47:57 PST 2019
Hi Changwei,
On 2019/2/18 17:25, Changwei Ge wrote:
> Hi Jun,
>
> On 2019/2/15 17:49, piaojun wrote:
>> Hi Changwei,
>>
>> On 2019/2/15 17:27, Changwei Ge wrote:
>>> On 2019/2/15 17:20, piaojun wrote:
>>>> Hi Changwei,
>>>>
>>>> On 2019/2/15 15:56, Changwei Ge wrote:
>>>>> Hi Jun
>>>>>
>>>>> I just read the code around unlock/cancel.
>>>>>
>>>>> On 2019/2/15 15:35, piaojun wrote:
>>>>>> Hi Changwei,
>>>>>>
>>>>>> On 2019/2/15 15:06, Changwei Ge wrote:
>>>>>>> Hi Jun,
>>>>>>>
>>>>>>> On 2019/2/15 14:51, piaojun wrote:
>>>>>>>> Hi Changwei,
>>>>>>>>
>>>>>>>> On 2019/2/14 18:13, Changwei Ge wrote:
>>>>>>>>> On 2019/2/14 17:09, piaojun wrote:
>>>>>>>>>> Hi Changwei,
>>>>>>>>>>
>>>>>>>>>> The problem can't be solved completely if clear ::cancel_pending in
>>>>>>>>>> dlm_proxy_ast_handler, as AST will come at anytime just before
>>>>>>>>>
>>>>>>>>> So how about also add check here bere setting ::cancel_pending in dlmunlock_common() before invoking dlm_send_remote_unlock_request().
>>>>>>>>> If already on grant list just return DLM_CANCELGRANT
>>>>>>>>>
>>>>>>>>> Then a further reference code might look like:
>>>>>>>>>
>>>>>>>>> root at ubuntu16:/home/chge/linux[master]# git diff
>>>>>>>>> diff --git a/fs/ocfs2/dlm/dlmast.c b/fs/ocfs2/dlm/dlmast.c
>>>>>>>>> index 39831fc..812843b 100644
>>>>>>>>> --- a/fs/ocfs2/dlm/dlmast.c
>>>>>>>>> +++ b/fs/ocfs2/dlm/dlmast.c
>>>>>>>>> @@ -372,8 +372,11 @@ int dlm_proxy_ast_handler(struct o2net_msg *msg, u32 len, void *data,
>>>>>>>>> head = &res->converting;
>>>>>>>>> lock = NULL;
>>>>>>>>> list_for_each_entry(lock, head, list) {
>>>>>>>>> - if (lock->ml.cookie == cookie)
>>>>>>>>> + if (lock->ml.cookie == cookie) {
>>>>>>>>> + if (lock->cancel_pending)
>>>>>>>>> + lock->cancel_pending = 0;
>>>>>>>>> goto do_ast;
>>>>>>>>> + }
>>>>>>>>> }
>>>>>>>>>
>>>>>>>>> /* if not on convert, try blocked for ast, granted for bast */
>>>>>>>>> diff --git a/fs/ocfs2/dlm/dlmunlock.c b/fs/ocfs2/dlm/dlmunlock.c
>>>>>>>>> index c8e9b70..b4728b5 100644
>>>>>>>>> --- a/fs/ocfs2/dlm/dlmunlock.c
>>>>>>>>> +++ b/fs/ocfs2/dlm/dlmunlock.c
>>>>>>>>> @@ -174,9 +174,14 @@ static enum dlm_status dlmunlock_common(struct dlm_ctxt *dlm,
>>>>>>>>> if (!master_node) {
>>>>>>>>> owner = res->owner;
>>>>>>>>> /* drop locks and send message */
>>>>>>>>> - if (flags & LKM_CANCEL)
>>>>>>>>> + if (flags & LKM_CANCEL) {
>>>>>>>>> + if (dlm_lock_on_list(&res->granted, lock)) {
>>>>>>>>> + status = DLM_CANCELGRANT;
>>>>>>>>> + goto leave;
>>>>>
>>>>> I found that above code should be useless.
>>>>> As upstream code already take it into consideration that AST has come before cancellation.
>>>>> In dlm_get_cancel_actions()
>>>>> '''
>>>>> } else if (dlm_lock_on_list(&res->granted, lock)) {
>>>>> /* too late, already granted. */
>>>>> status = DLM_CANCELGRANT;
>>>>> *actions = DLM_UNLOCK_CALL_AST;
>>>>> } else {
>>>>> '''
>>>>>
>>>>>>>>
>>>>>>>> If master dead and then lockres is moved to granted list in
>>>>>>>> dlm_move_lockres_to_recovery_list, the OCFS2_LOCK_BUSY is not cleared.
>>>>>>>
>>>>>>> OCFS2_LOCK_BUSY should be cleared in ocfs2_locking_ast() since previous locking AST has come back(moving lock to grant list).
>>>>>>> That's why we return DLM_CANCELGRANT to caller to avoid calling AST. Otherwise ast() will be called twice, which is obviously a BUG.
>>>>>>
>>>>>> I mean master is already dead and ast won't come. So the
>>>>>> OCFS2_LOCK_BUSY is not cleared. And there are two cases that lockres is
>>>>>> moved to grant list:
>>>>>> 1. AST comes back and OCFS2_LOCK_BUSY is cleared.
>>>>>> 2. AST does not come back and OCFS2_LOCK_BUSY remains, recovery process
>>>>>> move it to grant list. In this case, we need do AST for it.
>>>>>
>>>>> For point 2, ocfs2 can handle it, so you still don't have to worry. It's no problem.
>>>>> In dlmconvert_remote()
>>>>
>>>> What I worry about is that OCFS2_LOCK_BUSY won't be cleared if remote
>>>> master is dead, as OCFS2_LOCK_BUSY is cleared in two cases:
>>>> 1. remote AST come, clear it in dlm_proxy_ast_handler.
>>>> 2. remote AST does not come when master dead, clear it in
>>>> o2dlm_unlock_ast_wrapper.
>
> If AST doesn't manage to get back to requested node, why must flag OCFS2_LOCK_BUSY be cleared in o2dlm_unlock_ast_wrapper?
>
> Yes, OCFS2_LOCK_BUSY can be cleared it either o2dlm_unlock_ast_wrapper() or o2dlm_lock_ast_wrapper() with o2cb stack applied.
>
> If we return DLM_CANCELGRANT from ocfs2/dlm to dlm, then we must know that AST has ever come back or master node has moved the lock to grant list itself, thus we clear flag OCFS2_LOCK_BUSY in o2dlm_lock_ast_wrapper().
> Otherwise we ascertain that we can stop current ongoing locking procedure and must clear OCFS2_LOCK_BUSY in o2dlm_unlock_ast_wrapper() (*synchronized*).
>
> Let's summarize this, OCFS2_LOCK_BUSY should be cleared whether by locking success or cancellation success.
>
> And my way already check if the lock is granted then return DLM_CANCELGRANT or not.
>
OCFS2_LOCK_BUSY won't be cleared if DLM_CANCELGRANT is set in
o2dlm_unlock_ast_wrapper, and that's what I'm concerned about:
static void o2dlm_unlock_ast_wrapper(void *astarg, enum dlm_status status)
{
struct ocfs2_dlm_lksb *lksb = astarg;
int error = dlm_status_to_errno(status);
/*
* In o2dlm, you can get both the lock_ast() for the lock being
* granted and the unlock_ast() for the CANCEL failing. A
* successful cancel sends DLM_NORMAL here. If the
* lock grant happened before the cancel arrived, you get
* DLM_CANCELGRANT.
*
* There's no need for the double-ast. If we see DLM_CANCELGRANT,
* we just ignore it. We expect the lock_ast() to handle the
* granted lock.
*/
if (status == DLM_CANCELGRANT)
return;
lksb->lksb_conn->cc_proto->lp_unlock_ast(lksb, error);
}
>>>
>>> Please don't worry about point 2.
>>> Like my previous e-mail, after dlm recovery picking up a new master for corresponding lock resource.
>>> dlmlock() -> convert will retry and send request to new master.
>>> Eventually, this locking(convert) will succeed and ast() will be called for ocfs2 layer to clear OCFS2_LOCK_BUSY.
>>
>> Perhaps you misunderstand my meaning. The AST I meant is for dlmunlock,
>> not for dlmlock, so it won't cause retry sending request to new master.
>
> If the unlocking AST is not back then dlm_send_remote_unlock_request() returns NORMAL.
> Because unlocking AST is synchronized with unlocking request, which means master won't sent back a separated message back(proxy ast type).
> That means *status* returned from dlm_send_remote_unlock_request() indicates AST for unlocking should be called or not.
> How can AST for unlocking can't be invoked.
Sure, unlocking AST will be invoked, but do nothing(including clear
OCFS2_LOCK_BUSY).
>
> You really make me puzzled. :- (((
>
> Thanks,
> Changwei
>
>>
>>>
>>> Thanks,
>>> Changwei
>>>
>>>>
>>>> For case 2, if DLM_CANCELGRANT is set, o2dlm_unlock_ast_wrapper just
>>>> return and won't clear OCFS2_LOCK_BUSY. So in this case, I think we
>>>> should do AST again for it.
>>>>
>>>>>
>>>>>
>>>>> 341 if (status != DLM_NORMAL) {
>>>>> 342 if (status != DLM_NOTQUEUED)
>>>>> 343 dlm_error(status);
>>>>> 344 dlm_revert_pending_convert(res, lock);
>>>>> 345 } else if (!lock->convert_pending) {
>>>>> 346 mlog(0, "%s: res %.*s, owner died and lock has been moved back "
>>>>> 347 "to granted list, retry convert.\n",
>>>>> 348 dlm->name, res->lockname.len, res->lockname.name);
>>>>> 349 status = DLM_RECOVERING;
>>>>> 350 }
>>>>>
>>>>> Thus, dlmlock() will wait until RECOVERY is done.
>>>>> And for ocfs2 layer, it's apparent, it doesn't have to be aware of what happened to DLM.
>>>>
>>>> I do not think the waiting can solve this problem.
>>>>
>>>>>
>>>>> Thanks,
>>>>> Changwei
>>>>>
>>>>>
>>>>>>
>>>>>> Perhaps we need do AST again for it.
>>>>>>
>>>>>>>
>>>>>>>> And this will cause stuck problem when ocfs2_drop_lock. The reason is
>>>>>>>> that unlock ast won't be done when DLM_CANCELGRANT is set. So I think
>>>>>>>
>>>>>>> With above elaboration, you don't have to worry the hang issue anymore.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Changwei
>>>>>>>
>>>>>>>> we need distinguish all the cases of moving lockres to grant list.
>>>>>>>>
>>>>>>>>> + }
>>>>>>>>> +
>>>>>>>>> lock->cancel_pending = 1;
>>>>>>>>> - else
>>>>>>>>> + } else
>>>>>>>>> lock->unlock_pending = 1;
>>>>>>>>> spin_unlock(&lock->spinlock);
>>>>>>>>> spin_unlock(&res->spinlock);
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Thanks,
>>>>>>>>> Changwei
>>>>>>>>>
>>>>>>>>>> ::cancel_pendig is set. If there is not any other better solutions,
>>>>>>>>>> could we accept this patch? This bug is very harmful.
>>>>>>>>>>
>>>>>>>>>> Thanks,
>>>>>>>>>> Jun
>>>>>>>>>>
>>>>>>>>>> On 2018/12/8 18:05, wangjian wrote:
>>>>>>>>>>> Hi Changwei,
>>>>>>>>>>>
>>>>>>>>>>> I understand your idea. But we should be aware that the cancel_convert process and
>>>>>>>>>>> other processes (accepting the AST process, the recovery process) are asynchronous.
>>>>>>>>>>> For example, according to your idea, check if the lock is in the grant queue before
>>>>>>>>>>> calling the dlm_send_remote_unlock_request function in the dlm_proxy_ast_handler function.
>>>>>>>>>>> Then decide whether to clear cancel_pending. But if the AST does not come at this time,
>>>>>>>>>>> the check passes and cancel_pendig will not be cleared. Then AST immediately came over again,
>>>>>>>>>>> which also led to a bug. I personally think that for asynchronous processes we can't guarantee
>>>>>>>>>>> the speed of execution of each process. All we can do is to avoid the BUG scene.
>>>>>>>>>>>
>>>>>>>>>>> As for the question you said ("If you remove the BUG check why you still call dlm_commit_pending_cancel()
>>>>>>>>>>> to move the lock back to grant on matter it's on converting list or not?").
>>>>>>>>>>> I think we should first check if the lock is in the grant queue
>>>>>>>>>>> (at this time, dlm->spinlock and res->spinlock have been added), then decide whether to call
>>>>>>>>>>> dlm_commit_pending_cancel function.
>>>>>>>>>>>
>>>>>>>>>>> Thanks,
>>>>>>>>>>> Jian
>>>>>>>>>>>
>>>>>>>>>>> On 12/7/2018 11:12 AM, Changwei Ge wrote:
>>>>>>>>>>>> Hi Jian,
>>>>>>>>>>>>
>>>>>>>>>>>> I suppose that the situation you described truly exists.
>>>>>>>>>>>> But the way you fix the issue is not in my favor.
>>>>>>>>>>>>
>>>>>>>>>>>> If you remove the BUG check why you still call dlm_commit_pending_cancel() to
>>>>>>>>>>>> move the lock back to grant on matter it's on converting list or not?
>>>>>>>>>>>>
>>>>>>>>>>>> So how about keeping the BUG check in dlm_move_lockres_to_recovery_list().
>>>>>>>>>>>> If the locking _ast_ comes back very fast just check ::cancel_pending in dlm_proxy_ast_handler() and clear it.
>>>>>>>>>>>> Then with the logic checking if the lock is on grant list (in dlmunlock_common() more less like your current method)
>>>>>>>>>>>> or not we can easily tell if the cancellation succeeds or not.
>>>>>>>>>>>>
>>>>>>>>>>>> That complies the original dlm design, which I think is better and easier for maintainers to understand.
>>>>>>>>>>>>
>>>>>>>>>>>> Thanks,
>>>>>>>>>>>> Changwei
>>>>>>>>>>>>
>>>>>>>>>>>> On 2018/12/6 20:06, wangjian wrote:
>>>>>>>>>>>>> Hi Changwei,
>>>>>>>>>>>>>
>>>>>>>>>>>>> I don't fully agree with your point of view. In my opinion, the lock cancellation process and the lock
>>>>>>>>>>>>> conversion process are asynchronous. We can't guarantee that the lock must be in the convert list
>>>>>>>>>>>>> during the lock conversion process, otherwise this BUG will not happen.
>>>>>>>>>>>>> So, I think this is a meaningless BUG.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>> Jian
>>>>>>>>>>>>>
>>>>>>>>>>>>> On 12/5/2018 9:49 AM, Changwei Ge wrote:
>>>>>>>>>>>>>> Hi Jian,
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> I suppose you can't just remove the BUG_ON() check.
>>>>>>>>>>>>>> If you remove it, below code violates the original logic.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> '''
>>>>>>>>>>>>>> 2141 dlm_commit_pending_cancel(res, lock);
>>>>>>>>>>>>>> '''
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> What's more important is *locking cancel* must be against a *locking conversion* progress.
>>>>>>>>>>>>>> So it makes sense to check if this lock is on converting list.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> So I have to NACK to this patch.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>>> Changwei
>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> On 2018/12/3 20:23, wangjian wrote:
>>>>>>>>>>>>>>> In the dlm_move_lockres_to_recovery_list function, if the lock
>>>>>>>>>>>>>>> is in the granted queue and cancel_pending is set, it will
>>>>>>>>>>>>>>> encounter a BUG. I think this is a meaningless BUG,
>>>>>>>>>>>>>>> so be prepared to remove it. A scenario that causes
>>>>>>>>>>>>>>> this BUG will be given below.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> At the beginning, Node 1 is the master and has NL lock,
>>>>>>>>>>>>>>> Node 2 has PR lock, Node 3 has PR lock too.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Node 1 Node 2 Node 3
>>>>>>>>>>>>>>> want to get EX lock.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> want to get EX lock.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Node 3 hinder
>>>>>>>>>>>>>>> Node 2 to get
>>>>>>>>>>>>>>> EX lock, send
>>>>>>>>>>>>>>> Node 3 a BAST.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> receive BAST from
>>>>>>>>>>>>>>> Node 1. downconvert
>>>>>>>>>>>>>>> thread begin to
>>>>>>>>>>>>>>> cancel PR to EX conversion.
>>>>>>>>>>>>>>> In dlmunlock_common function,
>>>>>>>>>>>>>>> downconvert thread has set
>>>>>>>>>>>>>>> lock->cancel_pending,
>>>>>>>>>>>>>>> but did not enter
>>>>>>>>>>>>>>> dlm_send_remote_unlock_request
>>>>>>>>>>>>>>> function.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Node2 dies because
>>>>>>>>>>>>>>> the host is powered down.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> In recovery process,
>>>>>>>>>>>>>>> clean the lock that
>>>>>>>>>>>>>>> related to Node2.
>>>>>>>>>>>>>>> then finish Node 3
>>>>>>>>>>>>>>> PR to EX request.
>>>>>>>>>>>>>>> give Node 3 a AST.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> receive AST from Node 1.
>>>>>>>>>>>>>>> change lock level to EX,
>>>>>>>>>>>>>>> move lock to granted list.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Node1 dies because
>>>>>>>>>>>>>>> the host is powered down.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> In dlm_move_lockres_to_recovery_list
>>>>>>>>>>>>>>> function. the lock is in the
>>>>>>>>>>>>>>> granted queue and cancel_pending
>>>>>>>>>>>>>>> is set. BUG_ON.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> But after clearing this BUG, process will encounter
>>>>>>>>>>>>>>> the second BUG in the ocfs2_unlock_ast function.
>>>>>>>>>>>>>>> Here is a scenario that will cause the second BUG
>>>>>>>>>>>>>>> in ocfs2_unlock_ast as follows:
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> At the beginning, Node 1 is the master and has NL lock,
>>>>>>>>>>>>>>> Node 2 has PR lock, Node 3 has PR lock too.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Node 1 Node 2 Node 3
>>>>>>>>>>>>>>> want to get EX lock.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> want to get EX lock.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Node 3 hinder
>>>>>>>>>>>>>>> Node 2 to get
>>>>>>>>>>>>>>> EX lock, send
>>>>>>>>>>>>>>> Node 3 a BAST.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> receive BAST from
>>>>>>>>>>>>>>> Node 1. downconvert
>>>>>>>>>>>>>>> thread begin to
>>>>>>>>>>>>>>> cancel PR to EX conversion.
>>>>>>>>>>>>>>> In dlmunlock_common function,
>>>>>>>>>>>>>>> downconvert thread has released
>>>>>>>>>>>>>>> lock->spinlock and res->spinlock,
>>>>>>>>>>>>>>> but did not enter
>>>>>>>>>>>>>>> dlm_send_remote_unlock_request
>>>>>>>>>>>>>>> function.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Node2 dies because
>>>>>>>>>>>>>>> the host is powered down.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> In recovery process,
>>>>>>>>>>>>>>> clean the lock that
>>>>>>>>>>>>>>> related to Node2.
>>>>>>>>>>>>>>> then finish Node 3
>>>>>>>>>>>>>>> PR to EX request.
>>>>>>>>>>>>>>> give Node 3 a AST.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> receive AST from Node 1.
>>>>>>>>>>>>>>> change lock level to EX,
>>>>>>>>>>>>>>> move lock to granted list,
>>>>>>>>>>>>>>> set lockres->l_unlock_action
>>>>>>>>>>>>>>> as OCFS2_UNLOCK_INVALID
>>>>>>>>>>>>>>> in ocfs2_locking_ast function.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Node2 dies because
>>>>>>>>>>>>>>> the host is powered down.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Node 3 realize that Node 1
>>>>>>>>>>>>>>> is dead, remove Node 1 from
>>>>>>>>>>>>>>> domain_map. downconvert thread
>>>>>>>>>>>>>>> get DLM_NORMAL from
>>>>>>>>>>>>>>> dlm_send_remote_unlock_request
>>>>>>>>>>>>>>> function and set *call_ast as 1.
>>>>>>>>>>>>>>> Then downconvert thread meet
>>>>>>>>>>>>>>> BUG in ocfs2_unlock_ast function.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> To avoid meet the second BUG, function dlmunlock_common shuold
>>>>>>>>>>>>>>> return DLM_CANCELGRANT if the lock is on granted list and
>>>>>>>>>>>>>>> the operation is canceled.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> Signed-off-by: Jian Wang<wangjian161 at huawei.com>
>>>>>>>>>>>>>>> Reviewed-by: Yiwen Jiang<jiangyiwen at huawei.com>
>>>>>>>>>>>>>>> ---
>>>>>>>>>>>>>>> fs/ocfs2/dlm/dlmrecovery.c | 1 -
>>>>>>>>>>>>>>> fs/ocfs2/dlm/dlmunlock.c | 5 +++++
>>>>>>>>>>>>>>> 2 files changed, 5 insertions(+), 1 deletion(-)
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> diff --git a/fs/ocfs2/dlm/dlmrecovery.c b/fs/ocfs2/dlm/dlmrecovery.c
>>>>>>>>>>>>>>> index 802636d..7489652 100644
>>>>>>>>>>>>>>> --- a/fs/ocfs2/dlm/dlmrecovery.c
>>>>>>>>>>>>>>> +++ b/fs/ocfs2/dlm/dlmrecovery.c
>>>>>>>>>>>>>>> @@ -2134,7 +2134,6 @@ void dlm_move_lockres_to_recovery_list(struct dlm_ctxt *dlm,
>>>>>>>>>>>>>>> * if this had completed successfully
>>>>>>>>>>>>>>> * before sending this lock state to the
>>>>>>>>>>>>>>> * new master */
>>>>>>>>>>>>>>> - BUG_ON(i != DLM_CONVERTING_LIST);
>>>>>>>>>>>>>>> mlog(0, "node died with cancel pending "
>>>>>>>>>>>>>>> "on %.*s. move back to granted list.\n",
>>>>>>>>>>>>>>> res->lockname.len, res->lockname.name);
>>>>>>>>>>>>>>> diff --git a/fs/ocfs2/dlm/dlmunlock.c b/fs/ocfs2/dlm/dlmunlock.c
>>>>>>>>>>>>>>> index 63d701c..505bb6c 100644
>>>>>>>>>>>>>>> --- a/fs/ocfs2/dlm/dlmunlock.c
>>>>>>>>>>>>>>> +++ b/fs/ocfs2/dlm/dlmunlock.c
>>>>>>>>>>>>>>> @@ -183,6 +183,11 @@ static enum dlm_status dlmunlock_common(struct dlm_ctxt *dlm,
>>>>>>>>>>>>>>> flags, owner);
>>>>>>>>>>>>>>> spin_lock(&res->spinlock);
>>>>>>>>>>>>>>> spin_lock(&lock->spinlock);
>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>> + if ((flags & LKM_CANCEL) &&
>>>>>>>>>>>>>>> + dlm_lock_on_list(&res->granted, lock))
>>>>>>>>>>>>>>> + status = DLM_CANCELGRANT;
>>>>>>>>>>>>>>> +
>>>>>>>>>>>>>>> /* if the master told us the lock was already granted,
>>>>>>>>>>>>>>> * let the ast handle all of these actions */
>>>>>>>>>>>>>>> if (status == DLM_CANCELGRANT) {
>>>>>>>>>>>>>>> --
>>>>>>>>>>>>>>> 1.8.3.1
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>> .
>>>>>>>>>>>>>>
>>>>>>>>>>>> .
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> _______________________________________________
>>>>>>>>>>> Ocfs2-devel mailing list
>>>>>>>>>>> Ocfs2-devel at oss.oracle.com
>>>>>>>>>>> https://oss.oracle.com/mailman/listinfo/ocfs2-devel
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>> .
>>>>>>>>>
>>>>>>>>
>>>>>>> .
>>>>>>>
>>>>>>
>>>>> .
>>>>>
>>>>
>>> .
>>>
>>
> .
>
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