piaojun
2016-Jul-12 02:05 UTC
[Ocfs2-devel] [PATCH v2 1/3] ocfs2/dlm: disable BUG_ON when DLM_LOCK_RES_DROPPING_REF is cleared before dlm_deref_lockres_done_handler
We found a BUG situation in which DLM_LOCK_RES_DROPPING_REF is cleared
unexpected that described below. To solve the bug, we disable the BUG_ON
and purge lockres in dlm_do_local_recovery_cleanup.
Node 1 Node 2(master)
dlm_purge_lockres
dlm_deref_lockres_handler
DLM_LOCK_RES_SETREF_INPROG is set
response DLM_DEREF_RESPONSE_INPROG
receive DLM_DEREF_RESPONSE_INPROG
stop puring in dlm_purge_lockres
and wait for DLM_DEREF_RESPONSE_DONE
dispatch dlm_deref_lockres_worker
response DLM_DEREF_RESPONSE_DONE
receive DLM_DEREF_RESPONSE_DONE and
prepare to purge lockres
Node 2 goes down
find Node2 down and do local
clean up for Node2:
dlm_do_local_recovery_cleanup
-> clear DLM_LOCK_RES_DROPPING_REF
when purging lockres, BUG_ON happens
because DLM_LOCK_RES_DROPPING_REF is clear:
dlm_deref_lockres_done_handler
->BUG_ON(!(res->state & DLM_LOCK_RES_DROPPING_REF));
Fixes: 60d663cb5273 ("ocfs2/dlm: add DEREF_DONE message")
Signed-off-by: Jun Piao <piaojun at huawei.com>
Reviewed-by: Joseph Qi <joseph.qi at huawei.com>
Reviewed-by: Jiufei Xue <xuejiufei at huawei.com>
---
fs/ocfs2/dlm/dlmmaster.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/fs/ocfs2/dlm/dlmmaster.c b/fs/ocfs2/dlm/dlmmaster.c
index 9aed6e2..9456217 100644
--- a/fs/ocfs2/dlm/dlmmaster.c
+++ b/fs/ocfs2/dlm/dlmmaster.c
@@ -2416,7 +2416,17 @@ int dlm_deref_lockres_done_handler(struct o2net_msg *msg,
u32 len, void *data,
}
spin_lock(&res->spinlock);
- BUG_ON(!(res->state & DLM_LOCK_RES_DROPPING_REF));
+ if (!(res->state & DLM_LOCK_RES_DROPPING_REF)) {
+ spin_unlock(&res->spinlock);
+ spin_unlock(&dlm->spinlock);
+ mlog(ML_NOTICE, "%s:%.*s: node %u sends deref done "
+ "but it is already derefed!\n", dlm->name,
+ res->lockname.len, res->lockname.name, node);
+ dlm_lockres_put(res);
+ ret = 0;
+ goto done;
+ }
+
if (!list_empty(&res->purge)) {
mlog(0, "%s: Removing res %.*s from purgelist\n",
dlm->name, res->lockname.len, res->lockname.name);
@@ -2455,6 +2465,8 @@ int dlm_deref_lockres_done_handler(struct o2net_msg *msg,
u32 len, void *data,
spin_unlock(&dlm->spinlock);
+ ret = 0;
+
done:
dlm_put(dlm);
return ret;
--
1.8.4.3