[Ocfs2-devel] [patch 1/2] ocfs2/dlm: protect 'tracking_list' by 'track_lock'
piaojun
piaojun at huawei.com
Mon Sep 25 17:39:31 PDT 2017
On 2017/9/25 18:35, Joseph Qi wrote:
>
>
> On 17/9/23 11:39, piaojun wrote:
>> 'dlm->tracking_list' need to be protected by 'dlm->track_lock'.
>>
>> Signed-off-by: Jun Piao <piaojun at huawei.com>
>> Reviewed-by: Alex Chen <alex.chen at huawei.com>
>> ---
>> fs/ocfs2/dlm/dlmdomain.c | 7 ++++++-
>> fs/ocfs2/dlm/dlmmaster.c | 4 ++--
>> 2 files changed, 8 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/ocfs2/dlm/dlmdomain.c b/fs/ocfs2/dlm/dlmdomain.c
>> index a2b19fb..b118525 100644
>> --- a/fs/ocfs2/dlm/dlmdomain.c
>> +++ b/fs/ocfs2/dlm/dlmdomain.c
>> @@ -726,12 +726,17 @@ void dlm_unregister_domain(struct dlm_ctxt *dlm)
>> }
>>
>> /* This list should be empty. If not, print remaining lockres */
>> + spin_lock(&dlm->track_lock);
>> if (!list_empty(&dlm->tracking_list)) {
>> mlog(ML_ERROR, "Following lockres' are still on the "
>> "tracking list:\n");
>> - list_for_each_entry(res, &dlm->tracking_list, tracking)
>> + list_for_each_entry(res, &dlm->tracking_list, tracking) {
>> + spin_unlock(&dlm->track_lock);
>
> Um... If we unlock here, the iterator still has chance to be corrupted.
>
> Thanks,
> Joseph
>
we don't need care much about the corrupted 'tracking_list' because we
have already picked up 'res' from 'tracking_list'. then we will get
'track_lock' again to prevent 'tracking_list' from being corrupted. but
I'd better make sure that 'res' is not NULL before printing, just like:
list_for_each_entry(res, &dlm->tracking_list, tracking) {
spin_unlock(&dlm->track_lock);
if (res)
dlm_print_one_lock_resource(res);
spin_lock(&dlm->track_lock);
}
Thanks
Jun
>> dlm_print_one_lock_resource(res);
>> + spin_lock(&dlm->track_lock);
>> + }
>> }
>> + spin_unlock(&dlm->track_lock);
>>
>> dlm_mark_domain_leaving(dlm);
>> dlm_leave_domain(dlm);
>> diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c
>> index 3e04279..44e7d18 100644
>> --- a/fs/ocfs2/dlm/dlmmaster.c
>> +++ b/fs/ocfs2/dlm/dlmmaster.c
>> @@ -589,9 +589,9 @@ static void dlm_init_lockres(struct dlm_ctxt *dlm,
>>
>> res->last_used = 0;
>>
>> - spin_lock(&dlm->spinlock);
>> + spin_lock(&dlm->track_lock);
>> list_add_tail(&res->tracking, &dlm->tracking_list);
>> - spin_unlock(&dlm->spinlock);
>> + spin_unlock(&dlm->track_lock);
>>
>> memset(res->lvb, 0, DLM_LVB_LEN);
>> memset(res->refmap, 0, sizeof(res->refmap));
>>
> .
>
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