[Ocfs2-devel] [PATCH] ocfs2/dlm: wait for dlm recovery done when migrating all lock resources

[piaojun]

Wait for dlm recovery done when migrating all lock resources in case that
new lock resource left after leaving dlm domain. And the left lock
resource will cause other nodes BUG.

      NodeA                       NodeB                NodeC

umount:
  dlm_unregister_domain()
    dlm_migrate_all_locks()

                                 NodeB down

do recovery for NodeB
and collect a new lockres
form other live nodes:

  dlm_do_recovery
    dlm_remaster_locks
      dlm_request_all_locks:

  dlm_mig_lockres_handler
    dlm_new_lockres
      __dlm_insert_lockres

at last NodeA become the
master of the new lockres
and leave domain:
  dlm_leave_domain()

                                                  mount:
                                                    dlm_join_domain()

                                                  touch file and request
                                                  for the owner of the new
                                                  lockres, but all the
                                                  other nodes said 'NO',
                                                  so NodeC decide to be
                                                  the owner, and send do
                                                  assert msg to other
                                                  nodes:
                                                  dlmlock()
                                                    dlm_get_lock_resource()
                                                      dlm_do_assert_master()

                                                  other nodes receive the msg
                                                  and found two masters exist.
                                                  at last cause BUG in
                                                  dlm_assert_master_handler()
                                                  -->BUG();

Fixes: bc9838c4d44a ("dlm: allow dlm do recovery during shutdown")

Signed-off-by: Jun Piao <piaojun at huawei.com>
Reviewed-by: Alex Chen <alex.chen at huawei.com>
Reviewed-by: Yiwen Jiang <jiangyiwen at huawei.com>
---
 fs/ocfs2/dlm/dlmcommon.h   |  1 +
 fs/ocfs2/dlm/dlmdomain.c   | 15 +++++++++++++++
 fs/ocfs2/dlm/dlmrecovery.c | 13 ++++++++++---
 3 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/fs/ocfs2/dlm/dlmcommon.h b/fs/ocfs2/dlm/dlmcommon.h
index 953c200..d06e27e 100644
--- a/fs/ocfs2/dlm/dlmcommon.h
+++ b/fs/ocfs2/dlm/dlmcommon.h
@@ -140,6 +140,7 @@ struct dlm_ctxt
 	u8 node_num;
 	u32 key;
 	u8  joining_node;
+	u8 migrate_done; /* set to 1 means node has migrated all lock resources */
 	wait_queue_head_t dlm_join_events;
 	unsigned long live_nodes_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
 	unsigned long domain_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
diff --git a/fs/ocfs2/dlm/dlmdomain.c b/fs/ocfs2/dlm/dlmdomain.c
index 25b76f0..425081b 100644
--- a/fs/ocfs2/dlm/dlmdomain.c
+++ b/fs/ocfs2/dlm/dlmdomain.c
@@ -461,6 +461,19 @@ static int dlm_migrate_all_locks(struct dlm_ctxt *dlm)
 		cond_resched_lock(&dlm->spinlock);
 		num += n;
 	}
+
+	if (!num) {
+		if (dlm->reco.state & DLM_RECO_STATE_ACTIVE) {
+			mlog(0, "%s: perhaps there are more lock resources "
+			     "need to be migrated after dlm recovery\n", dlm->name);
+			ret = -EAGAIN;
+		} else {
+			mlog(0, "%s: we won't do dlm recovery after migrating "
+			     "all lock resources\n", dlm->name);
+			dlm->migrate_done = 1;
+		}
+	}
+
 	spin_unlock(&dlm->spinlock);
 	wake_up(&dlm->dlm_thread_wq);

@@ -2038,6 +2051,8 @@ static struct dlm_ctxt *dlm_alloc_ctxt(const char *domain,
 	dlm->joining_node = DLM_LOCK_RES_OWNER_UNKNOWN;
 	init_waitqueue_head(&dlm->dlm_join_events);

+	dlm->migrate_done = 0;
+
 	dlm->reco.new_master = O2NM_INVALID_NODE_NUM;
 	dlm->reco.dead_node = O2NM_INVALID_NODE_NUM;

diff --git a/fs/ocfs2/dlm/dlmrecovery.c b/fs/ocfs2/dlm/dlmrecovery.c
index 505ab42..d4336a5 100644
--- a/fs/ocfs2/dlm/dlmrecovery.c
+++ b/fs/ocfs2/dlm/dlmrecovery.c
@@ -423,12 +423,11 @@ void dlm_wait_for_recovery(struct dlm_ctxt *dlm)

 static void dlm_begin_recovery(struct dlm_ctxt *dlm)
 {
-	spin_lock(&dlm->spinlock);
+	assert_spin_locked(&dlm->spinlock);
 	BUG_ON(dlm->reco.state & DLM_RECO_STATE_ACTIVE);
 	printk(KERN_NOTICE "o2dlm: Begin recovery on domain %s for node %u\n",
 	       dlm->name, dlm->reco.dead_node);
 	dlm->reco.state |= DLM_RECO_STATE_ACTIVE;
-	spin_unlock(&dlm->spinlock);
 }

 static void dlm_end_recovery(struct dlm_ctxt *dlm)
@@ -456,6 +455,13 @@ static int dlm_do_recovery(struct dlm_ctxt *dlm)

 	spin_lock(&dlm->spinlock);

+	if (dlm->migrate_done) {
+		mlog(0, "%s: no need do recovery after migrating all "
+		     "lock resources\n", dlm->name);
+		spin_unlock(&dlm->spinlock);
+		return 0;
+	}
+
 	/* check to see if the new master has died */
 	if (dlm->reco.new_master != O2NM_INVALID_NODE_NUM &&
 	    test_bit(dlm->reco.new_master, dlm->recovery_map)) {
@@ -490,12 +496,13 @@ static int dlm_do_recovery(struct dlm_ctxt *dlm)
 	mlog(0, "%s(%d):recovery thread found node %u in the recovery map!\n",
 	     dlm->name, task_pid_nr(dlm->dlm_reco_thread_task),
 	     dlm->reco.dead_node);
-	spin_unlock(&dlm->spinlock);

 	/* take write barrier */
 	/* (stops the list reshuffling thread, proxy ast handling) */
 	dlm_begin_recovery(dlm);

+	spin_unlock(&dlm->spinlock);
+
 	if (dlm->reco.new_master == dlm->node_num)
 		goto master_here;

--