| Message ID | 51C2E3F1.5020605@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
it is fine. because when the lock add to the block list. it should be return DLM_NORMAL. Reviewed-by: jensen <shencanquan@huawei.com> On 2013/6/20 19:13, Xue jiufei wrote: > Function dlmlock_master() returns DLM_RECOVERING/DLM_MIGRATING/ > DLM_FORWAR after adding lock to blocked list if lockres has the state > DLM_LOCK_RES_RECOVERING/DLM_LOCK_RES_MIGRATING/ > DLM_LOCK_RES_IN_PROGRESS. so it will retry in dlmlock(). And this may > cause dlm_thread fall into an infinite loop > > Thread1 dlm_thread > calls dlm_lock->dlmlock_master, > if lockresA is in state > DLM_LOCK_RES_RECOVERING, calls > __dlm_wait_on_lockres() and waits > until others threads clear this > state; > > If cannot grant this lock, > adding lock to blocked list, > and return DLM_RECOVERING; > > Grant this lock and move it to > grant list; > > After a while, retry and > calls list_add_tail(), adding lock > to blocked list again. > > Granted and blocked list of this lockres will become the following > conditions: > lock_res->granted.next = dlm_lock->list_head; > lock_res->blocked.next = dlm_lock->list_head; > dlm_lock->list_head.next = dlm_lock_resource->blocked; > When dlm_thread traverses the granted list, it will fall into an > endless loop, checking dlm_lock.list_head, dlm_lock->list_head.next > (i.e.lock_res->blocked), lock_res->blocked.next(i.e.dlm_lock.list_head > again) ..... > > Signed-off-by: joyce <xuejiufei@huawei.com> > --- > fs/ocfs2/dlm/dlmlock.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/fs/ocfs2/dlm/dlmlock.c b/fs/ocfs2/dlm/dlmlock.c > index 975810b..47e67c2 100644 > --- a/fs/ocfs2/dlm/dlmlock.c > +++ b/fs/ocfs2/dlm/dlmlock.c > @@ -178,6 +178,7 @@ static enum dlm_status dlmlock_master(struct dlm_ctxt *dlm, > lock->ml.node); > } > } else { > + status = DLM_NORMAL; > dlm_lock_get(lock); > list_add_tail(&lock->list, &res->blocked); > kick_thread = 1;
Hi Jiufei, On 06/20/2013 07:13 PM, Xue jiufei wrote: > Function dlmlock_master() returns DLM_RECOVERING/DLM_MIGRATING/ > DLM_FORWAR after adding lock to blocked list if lockres has the state > DLM_LOCK_RES_RECOVERING/DLM_LOCK_RES_MIGRATING/ > DLM_LOCK_RES_IN_PROGRESS. so it will retry in dlmlock(). And this may > cause dlm_thread fall into an infinite loop > > Thread1 dlm_thread > calls dlm_lock->dlmlock_master, > if lockresA is in state > DLM_LOCK_RES_RECOVERING, calls > __dlm_wait_on_lockres() and waits > until others threads clear this > state; > > If cannot grant this lock, > adding lock to blocked list, > and return DLM_RECOVERING; > > Grant this lock and move it to > grant list; > > After a while, retry and > calls list_add_tail(), adding lock > to blocked list again. > > Granted and blocked list of this lockres will become the following > conditions: > lock_res->granted.next = dlm_lock->list_head; > lock_res->blocked.next = dlm_lock->list_head; > dlm_lock->list_head.next = dlm_lock_resource->blocked; > When dlm_thread traverses the granted list, it will fall into an > endless loop, checking dlm_lock.list_head, dlm_lock->list_head.next > (i.e.lock_res->blocked), lock_res->blocked.next(i.e.dlm_lock.list_head > again) ..... Thanks for your nice description of this problem and this fix looks good. Let's waiting for an ACK from either Sunil, Mark or Joel. -Jeff > > Signed-off-by: joyce <xuejiufei@huawei.com> > --- > fs/ocfs2/dlm/dlmlock.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/fs/ocfs2/dlm/dlmlock.c b/fs/ocfs2/dlm/dlmlock.c > index 975810b..47e67c2 100644 > --- a/fs/ocfs2/dlm/dlmlock.c > +++ b/fs/ocfs2/dlm/dlmlock.c > @@ -178,6 +178,7 @@ static enum dlm_status dlmlock_master(struct dlm_ctxt *dlm, > lock->ml.node); > } > } else { > + status = DLM_NORMAL; > dlm_lock_get(lock); > list_add_tail(&lock->list, &res->blocked); > kick_thread = 1;
diff --git a/fs/ocfs2/dlm/dlmlock.c b/fs/ocfs2/dlm/dlmlock.c index 975810b..47e67c2 100644 --- a/fs/ocfs2/dlm/dlmlock.c +++ b/fs/ocfs2/dlm/dlmlock.c @@ -178,6 +178,7 @@ static enum dlm_status dlmlock_master(struct dlm_ctxt *dlm, lock->ml.node); } } else { + status = DLM_NORMAL; dlm_lock_get(lock); list_add_tail(&lock->list, &res->blocked); kick_thread = 1;
Function dlmlock_master() returns DLM_RECOVERING/DLM_MIGRATING/ DLM_FORWAR after adding lock to blocked list if lockres has the state DLM_LOCK_RES_RECOVERING/DLM_LOCK_RES_MIGRATING/ DLM_LOCK_RES_IN_PROGRESS. so it will retry in dlmlock(). And this may cause dlm_thread fall into an infinite loop Thread1 dlm_thread calls dlm_lock->dlmlock_master, if lockresA is in state DLM_LOCK_RES_RECOVERING, calls __dlm_wait_on_lockres() and waits until others threads clear this state; If cannot grant this lock, adding lock to blocked list, and return DLM_RECOVERING; Grant this lock and move it to grant list; After a while, retry and calls list_add_tail(), adding lock to blocked list again. Granted and blocked list of this lockres will become the following conditions: lock_res->granted.next = dlm_lock->list_head; lock_res->blocked.next = dlm_lock->list_head; dlm_lock->list_head.next = dlm_lock_resource->blocked; When dlm_thread traverses the granted list, it will fall into an endless loop, checking dlm_lock.list_head, dlm_lock->list_head.next (i.e.lock_res->blocked), lock_res->blocked.next(i.e.dlm_lock.list_head again) ..... Signed-off-by: joyce <xuejiufei@huawei.com> --- fs/ocfs2/dlm/dlmlock.c | 1 + 1 file changed, 1 insertion(+)