xuejiufei
2015-Dec-30 09:56 UTC
[Ocfs2-devel] [PATCH] ocfs2/dlm: ignore cleaning the migration mle that is inuse
Hi Junxiao, You are right. But it may happen that mle->woken is set to 1 in dlm_clean_migration_mle() just after atomic_read() in dlm_migrate_lockres(). Actually we trigger this BUG when dlm_send_one_lockres() return error. And I think dlm_migrate_lockres() should not set owner to target and return 0 when mle->woken is set to 1 in dlm_clean_migration_mle(). This is another problem? Thanks Jiufei. On 2015/12/30 10:52, Junxiao Bi wrote:> Hi Jiufei, > > When target node down, mle is cleared from > dlm_do_local_recovery_cleanup()->dlm_clean_master_list()->dlm_clean_migration_mle()? > mle->woken is set to 1 in dlm_clean_migration_mle(), so the code to > detect target node down(if (dlm_is_node_dead(dlm, target))) will never > be run in dlm_migrate_lockres()? > > > 2621 while (1) { > 2622 ret = wait_event_interruptible_timeout(mle->wq, > 2623 (atomic_read(&mle->woken) > == 1), > 2624 msecs_to_jiffies(5000)); > 2625 > 2626 if (ret >= 0) { > 2627 if (atomic_read(&mle->woken) == 1 || > 2628 res->owner == target) > 2629 break; > 2630 > 2631 mlog(0, "%s:%.*s: timed out during > migration\n", > 2632 dlm->name, res->lockname.len, > res->lockname.name); > 2633 /* avoid hang during shutdown when > migrating lockres > 2634 * to a node which also goes down */ > 2635 if (dlm_is_node_dead(dlm, target)) { > 2636 mlog(0, "%s:%.*s: expected migration " > 2637 "target %u is no longer up, > restarting\n", > 2638 dlm->name, res->lockname.len, > 2639 res->lockname.name, target); > 2640 ret = -EINVAL; > 2641 /* migration failed, detach and > clean up mle */ > 2642 dlm_mle_detach_hb_events(dlm, mle); > 2643 dlm_put_mle(mle); > 2644 dlm_put_mle_inuse(mle); > 2645 spin_lock(&res->spinlock); > 2646 res->state &= ~DLM_LOCK_RES_MIGRATING; > 2647 wake = 1; > 2648 spin_unlock(&res->spinlock); > 2649 goto leave; > 2650 } > 2651 } else > 2652 mlog(0, "%s:%.*s: caught signal during > migration\n", > 2653 dlm->name, res->lockname.len, > res->lockname.name); > 2654 } > > > Thanks, > Junxiao. > On 12/28/2015 03:44 PM, xuejiufei wrote: >> We have found that migration source will trigger a BUG that the >> refcount of mle is already zero before put when the target is >> down during migration. The situation is as follows: >> >> dlm_migrate_lockres >> dlm_add_migration_mle >> dlm_mark_lockres_migrating >> dlm_get_mle_inuse >> <<<<<< Now the refcount of the mle is 2. >> dlm_send_one_lockres and wait for the target to become the >> new master. >> <<<<<< o2hb detect the target down and clean the migration >> mle. Now the refcount is 1. >> >> dlm_migrate_lockres woken, and put the mle twice when found >> the target goes down which trigger the BUG with the following >> message: >> "ERROR: bad mle: ". >> >> Signed-off-by: Jiufei Xue <xuejiufei at huawei.com> >> Reviewed-by: Joseph Qi <joseph.qi at huawei.com> >> --- >> fs/ocfs2/dlm/dlmmaster.c | 26 +++++++++++++++----------- >> 1 file changed, 15 insertions(+), 11 deletions(-) >> >> diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c >> index 936e11b..b713140 100644 >> --- a/fs/ocfs2/dlm/dlmmaster.c >> +++ b/fs/ocfs2/dlm/dlmmaster.c >> @@ -2519,6 +2519,11 @@ static int dlm_migrate_lockres(struct dlm_ctxt *dlm, >> spin_lock(&dlm->master_lock); >> ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name, >> namelen, target, dlm->node_num); >> + /* get an extra reference on the mle. >> + * otherwise the assert_master from the new >> + * master will destroy this. >> + */ >> + dlm_get_mle_inuse(mle); >> spin_unlock(&dlm->master_lock); >> spin_unlock(&dlm->spinlock); >> >> @@ -2554,6 +2559,7 @@ fail: >> if (mle_added) { >> dlm_mle_detach_hb_events(dlm, mle); >> dlm_put_mle(mle); >> + dlm_put_mle_inuse(mle); >> } else if (mle) { >> kmem_cache_free(dlm_mle_cache, mle); >> mle = NULL; >> @@ -2571,17 +2577,6 @@ fail: >> * ensure that all assert_master work is flushed. */ >> flush_workqueue(dlm->dlm_worker); >> >> - /* get an extra reference on the mle. >> - * otherwise the assert_master from the new >> - * master will destroy this. >> - * also, make sure that all callers of dlm_get_mle >> - * take both dlm->spinlock and dlm->master_lock */ >> - spin_lock(&dlm->spinlock); >> - spin_lock(&dlm->master_lock); >> - dlm_get_mle_inuse(mle); >> - spin_unlock(&dlm->master_lock); >> - spin_unlock(&dlm->spinlock); >> - >> /* notify new node and send all lock state */ >> /* call send_one_lockres with migration flag. >> * this serves as notice to the target node that a >> @@ -3312,6 +3307,15 @@ top: >> mle->new_master != dead_node) >> continue; >> >> + if (mle->new_master == dead_node && mle->inuse) { >> + mlog(ML_NOTICE, "%s: target %u died during " >> + "migration from %u, the MLE is " >> + "still keep used, ignore it!\n", >> + dlm->name, dead_node, >> + mle->master); >> + continue; >> + } >> + >> /* If we have reached this point, this mle needs to be >> * removed from the list and freed. */ >> dlm_clean_migration_mle(dlm, mle); >> > > > . >
Junxiao Bi
2015-Dec-31 03:05 UTC
[Ocfs2-devel] [PATCH] ocfs2/dlm: ignore cleaning the migration mle that is inuse
On 12/30/2015 05:56 PM, xuejiufei wrote:> Hi Junxiao, > You are right. But it may happen that mle->woken is set to 1 in > dlm_clean_migration_mle() just after atomic_read() in > dlm_migrate_lockres(). Actually we trigger this BUG when dlm_send_one_lockres() > return error.Yes, that's possible because of that 5s timeout wakeup, I think this timeout is useless and can be removed?> > And I think dlm_migrate_lockres() should not set owner to target and return 0 > when mle->woken is set to 1 in dlm_clean_migration_mle(). This is another problem?Yes, it should be fixed, or the lockres owner will be set to a down node wrongly. Can the following fix these two issue? diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c index 84f2f8079466..d0380ea62340 100644 --- a/fs/ocfs2/dlm/dlmmaster.c +++ b/fs/ocfs2/dlm/dlmmaster.c @@ -2618,39 +2618,22 @@ fail: /* wait for new node to assert master */ - while (1) { - ret = wait_event_interruptible_timeout(mle->wq, - (atomic_read(&mle->woken) == 1), - msecs_to_jiffies(5000)); - - if (ret >= 0) { - if (atomic_read(&mle->woken) == 1 || - res->owner == target) - break; - - mlog(0, "%s:%.*s: timed out during migration\n", - dlm->name, res->lockname.len, res->lockname.name); - /* avoid hang during shutdown when migrating lockres - * to a node which also goes down */ - if (dlm_is_node_dead(dlm, target)) { - mlog(0, "%s:%.*s: expected migration " - "target %u is no longer up, restarting\n", - dlm->name, res->lockname.len, - res->lockname.name, target); - ret = -EINVAL; - /* migration failed, detach and clean up mle */ - dlm_mle_detach_hb_events(dlm, mle); - dlm_put_mle(mle); - dlm_put_mle_inuse(mle); - spin_lock(&res->spinlock); - res->state &= ~DLM_LOCK_RES_MIGRATING; - wake = 1; - spin_unlock(&res->spinlock); - goto leave; - } - } else - mlog(0, "%s:%.*s: caught signal during migration\n", - dlm->name, res->lockname.len, res->lockname.name); + wait_event(mle->wq, ((atomic_read(&mle->woken) == 1) || + (atomic_read(&mle->woken) == 2))); + + /* migrate target down */ + if (atomic_read(&mle->woken) == 2) { + mlog(0, "%s:%.*s: expected migration " + "target %u is no longer up, restarting\n", + dlm->name, res->lockname.len, + res->lockname.name, target); + ret = -EINVAL; + dlm_put_mle_inuse(mle); + spin_lock(&res->spinlock); + res->state &= ~DLM_LOCK_RES_MIGRATING; + wake = 1; + spin_unlock(&res->spinlock); + goto leave; } /* all done, set the owner, clear the flag */ @@ -3227,7 +3210,7 @@ static void dlm_clean_migration_mle(struct dlm_ctxt *dlm, spin_lock(&mle->spinlock); __dlm_unlink_mle(dlm, mle); - atomic_set(&mle->woken, 1); + atomic_set(&mle->woken, 2); spin_unlock(&mle->spinlock); wake_up(&mle->wq); Thanks, Junxiao.> > Thanks > Jiufei. > > On 2015/12/30 10:52, Junxiao Bi wrote: >> Hi Jiufei, >> >> When target node down, mle is cleared from >> dlm_do_local_recovery_cleanup()->dlm_clean_master_list()->dlm_clean_migration_mle()? >> mle->woken is set to 1 in dlm_clean_migration_mle(), so the code to >> detect target node down(if (dlm_is_node_dead(dlm, target))) will never >> be run in dlm_migrate_lockres()? >> >> >> 2621 while (1) { >> 2622 ret = wait_event_interruptible_timeout(mle->wq, >> 2623 (atomic_read(&mle->woken) >> == 1), >> 2624 msecs_to_jiffies(5000)); >> 2625 >> 2626 if (ret >= 0) { >> 2627 if (atomic_read(&mle->woken) == 1 || >> 2628 res->owner == target) >> 2629 break; >> 2630 >> 2631 mlog(0, "%s:%.*s: timed out during >> migration\n", >> 2632 dlm->name, res->lockname.len, >> res->lockname.name); >> 2633 /* avoid hang during shutdown when >> migrating lockres >> 2634 * to a node which also goes down */ >> 2635 if (dlm_is_node_dead(dlm, target)) { >> 2636 mlog(0, "%s:%.*s: expected migration " >> 2637 "target %u is no longer up, >> restarting\n", >> 2638 dlm->name, res->lockname.len, >> 2639 res->lockname.name, target); >> 2640 ret = -EINVAL; >> 2641 /* migration failed, detach and >> clean up mle */ >> 2642 dlm_mle_detach_hb_events(dlm, mle); >> 2643 dlm_put_mle(mle); >> 2644 dlm_put_mle_inuse(mle); >> 2645 spin_lock(&res->spinlock); >> 2646 res->state &= ~DLM_LOCK_RES_MIGRATING; >> 2647 wake = 1; >> 2648 spin_unlock(&res->spinlock); >> 2649 goto leave; >> 2650 } >> 2651 } else >> 2652 mlog(0, "%s:%.*s: caught signal during >> migration\n", >> 2653 dlm->name, res->lockname.len, >> res->lockname.name); >> 2654 } >> >> >> Thanks, >> Junxiao. >> On 12/28/2015 03:44 PM, xuejiufei wrote: >>> We have found that migration source will trigger a BUG that the >>> refcount of mle is already zero before put when the target is >>> down during migration. The situation is as follows: >>> >>> dlm_migrate_lockres >>> dlm_add_migration_mle >>> dlm_mark_lockres_migrating >>> dlm_get_mle_inuse >>> <<<<<< Now the refcount of the mle is 2. >>> dlm_send_one_lockres and wait for the target to become the >>> new master. >>> <<<<<< o2hb detect the target down and clean the migration >>> mle. Now the refcount is 1. >>> >>> dlm_migrate_lockres woken, and put the mle twice when found >>> the target goes down which trigger the BUG with the following >>> message: >>> "ERROR: bad mle: ". >>> >>> Signed-off-by: Jiufei Xue <xuejiufei at huawei.com> >>> Reviewed-by: Joseph Qi <joseph.qi at huawei.com> >>> --- >>> fs/ocfs2/dlm/dlmmaster.c | 26 +++++++++++++++----------- >>> 1 file changed, 15 insertions(+), 11 deletions(-) >>> >>> diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c >>> index 936e11b..b713140 100644 >>> --- a/fs/ocfs2/dlm/dlmmaster.c >>> +++ b/fs/ocfs2/dlm/dlmmaster.c >>> @@ -2519,6 +2519,11 @@ static int dlm_migrate_lockres(struct dlm_ctxt *dlm, >>> spin_lock(&dlm->master_lock); >>> ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name, >>> namelen, target, dlm->node_num); >>> + /* get an extra reference on the mle. >>> + * otherwise the assert_master from the new >>> + * master will destroy this. >>> + */ >>> + dlm_get_mle_inuse(mle); >>> spin_unlock(&dlm->master_lock); >>> spin_unlock(&dlm->spinlock); >>> >>> @@ -2554,6 +2559,7 @@ fail: >>> if (mle_added) { >>> dlm_mle_detach_hb_events(dlm, mle); >>> dlm_put_mle(mle); >>> + dlm_put_mle_inuse(mle); >>> } else if (mle) { >>> kmem_cache_free(dlm_mle_cache, mle); >>> mle = NULL; >>> @@ -2571,17 +2577,6 @@ fail: >>> * ensure that all assert_master work is flushed. */ >>> flush_workqueue(dlm->dlm_worker); >>> >>> - /* get an extra reference on the mle. >>> - * otherwise the assert_master from the new >>> - * master will destroy this. >>> - * also, make sure that all callers of dlm_get_mle >>> - * take both dlm->spinlock and dlm->master_lock */ >>> - spin_lock(&dlm->spinlock); >>> - spin_lock(&dlm->master_lock); >>> - dlm_get_mle_inuse(mle); >>> - spin_unlock(&dlm->master_lock); >>> - spin_unlock(&dlm->spinlock); >>> - >>> /* notify new node and send all lock state */ >>> /* call send_one_lockres with migration flag. >>> * this serves as notice to the target node that a >>> @@ -3312,6 +3307,15 @@ top: >>> mle->new_master != dead_node) >>> continue; >>> >>> + if (mle->new_master == dead_node && mle->inuse) { >>> + mlog(ML_NOTICE, "%s: target %u died during " >>> + "migration from %u, the MLE is " >>> + "still keep used, ignore it!\n", >>> + dlm->name, dead_node, >>> + mle->master); >>> + continue; >>> + } >>> + >>> /* If we have reached this point, this mle needs to be >>> * removed from the list and freed. */ >>> dlm_clean_migration_mle(dlm, mle); >>> >> >> >> . >> >