On 2017/12/18 19:52, Joseph Qi wrote:
>
>
> On 17/12/18 18:22, alex chen wrote:
>> In dlm_reset_mleres_owner(), we will lock
>> dlm_lock_resource->spinlock after locking dlm_ctxt->master_lock,
>> which breaks the spinlock lock ordering:
>> dlm_domain_lock
>> struct dlm_ctxt->spinlock
>> struct dlm_lock_resource->spinlock
>> struct dlm_ctxt->master_lock
>>
>> Fix it by unlocking dlm_ctxt->master_lock before locking
>> dlm_lock_resource->spinlock and restarting to clean master list.
>>
>> Signed-off-by: Alex Chen <alex.c...@huawei.com>
>> Reviewed-by: Jun Piao <piao...@huawei.com>
>> ---
>> fs/ocfs2/dlm/dlmmaster.c | 13 +++++++++++--
>> 1 file changed, 11 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c
>> index 3e04279..0df939a 100644
>> --- a/fs/ocfs2/dlm/dlmmaster.c
>> +++ b/fs/ocfs2/dlm/dlmmaster.c
>> @@ -3287,14 +3287,23 @@ static struct dlm_lock_resource
>> *dlm_reset_mleres_owner(struct dlm_ctxt *dlm,
>> {
>> struct dlm_lock_resource *res;
>>
>> + assert_spin_locked(&dlm->spinlock);
>> + assert_spin_locked(&dlm->master_lock);
>> +
>> /* Find the lockres associated to the mle and set its owner to UNK */
>> - res = __dlm_lookup_lockres(dlm, mle->mname, mle->mnamelen,
>> + res = __dlm_lookup_lockres_full(dlm, mle->mname, mle->mnamelen,
>> mle->mnamehash);
>> if (res) {
>> spin_unlock(&dlm->master_lock);
>>
>> - /* move lockres onto recovery list */
>> spin_lock(&res->spinlock);
>> + if (res->state & DLM_LOCK_RES_DROPPING_REF) {
>> + spin_unlock(&res->spinlock);
>> + dlm_lockres_put(res);
>> + return NULL;
>> + }
>
> We can't just return NULL here. Please note that we have to:
> return a valid lock resource with master_lock unlocked, or return NULL
> with master_lock.
> You patch will introduce unlocking master_lock twice.
Agree.
>
> Thanks,
> Joseph
>
>> +
>> + /* move lockres onto recovery list */
>> dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
>> dlm_move_lockres_to_recovery_list(dlm, res);
>> spin_unlock(&res->spinlock);
>>
>
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