| Message ID | 5668002C.3070107@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 12/09/2015 06:19 PM, jiangyiwen wrote: > commit f3f854648de6("ocfs2_dlm: Ensure correct ordering of set/clear > refmap bit on lockres") still exists a race which can't ensure the > ordering is exactly correct. > > Node1 Node2 Node3 > umount, migrate > lockres to Node2 > migrate finished, > send migrate request > to Node3 > received migrate request, > create a migration_mle, > respond to Node2. > set DLM_LOCK_RES_SETREF_INPROG > and send assert master to > Node3 > delete migration_mle in > assert_master_handler, > Node3 umount without response > dlm_thread purge > this lockres, send drop > deref message to Node2 > found the flag of > DLM_LOCK_RES_SETREF_INPROG > is set, dispatch > dlm_deref_lockres_worker to > clear refmap, but in function of > dlm_deref_lockres_worker, > only if node in refmap it wait > DLM_LOCK_RES_SETREF_INPROG > to be cleared. So worker is > done successfully > > purge lockres, send > assert master response > to Node1, and finish umount > set Node3 in refmap, and it > won't be cleared forever, thus > lead to umount hung > > so wait until DLM_LOCK_RES_SETREF_INPROG is cleared in > dlm_deref_lockres_worker. > > Signed-off-by: Yiwen Jiang <jiangyiwen@huawei.com> > Reviewed-by: Joseph Qi <joseph.qi@huawei.com> Looks good. Reviewed-by: Junxiao Bi <junxiao.bi@oracle.com> > --- > fs/ocfs2/dlm/dlmmaster.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c > index ce38b4c..666ea67 100644 > --- a/fs/ocfs2/dlm/dlmmaster.c > +++ b/fs/ocfs2/dlm/dlmmaster.c > @@ -2388,8 +2388,8 @@ static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data) > > spin_lock(&res->spinlock); > BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF); > + __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG); > if (test_bit(node, res->refmap)) { > - __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG); > dlm_lockres_clear_refmap_bit(dlm, res, node); > cleared = 1; > } >
diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c index ce38b4c..666ea67 100644 --- a/fs/ocfs2/dlm/dlmmaster.c +++ b/fs/ocfs2/dlm/dlmmaster.c @@ -2388,8 +2388,8 @@ static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data) spin_lock(&res->spinlock); BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF); + __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG); if (test_bit(node, res->refmap)) { - __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG); dlm_lockres_clear_refmap_bit(dlm, res, node); cleared = 1; }
commit f3f854648de6("ocfs2_dlm: Ensure correct ordering of set/clear refmap bit on lockres") still exists a race which can't ensure the ordering is exactly correct. Node1 Node2 Node3 umount, migrate lockres to Node2 migrate finished, send migrate request to Node3 received migrate request, create a migration_mle, respond to Node2. set DLM_LOCK_RES_SETREF_INPROG and send assert master to Node3 delete migration_mle in assert_master_handler, Node3 umount without response dlm_thread purge this lockres, send drop deref message to Node2 found the flag of DLM_LOCK_RES_SETREF_INPROG is set, dispatch dlm_deref_lockres_worker to clear refmap, but in function of dlm_deref_lockres_worker, only if node in refmap it wait DLM_LOCK_RES_SETREF_INPROG to be cleared. So worker is done successfully purge lockres, send assert master response to Node1, and finish umount set Node3 in refmap, and it won't be cleared forever, thus lead to umount hung so wait until DLM_LOCK_RES_SETREF_INPROG is cleared in dlm_deref_lockres_worker. Signed-off-by: Yiwen Jiang <jiangyiwen@huawei.com> Reviewed-by: Joseph Qi <joseph.qi@huawei.com> --- fs/ocfs2/dlm/dlmmaster.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)