ocfs2/dlm: avoid incorrect bit set in refmap on recovery master

In the following situation, there remains an incorrect bit in refmap on the
recovery master. Finally the recovery master will fail at purging the lockres
due to the incorrect bit in refmap.

1) node A has no interest on lockres A any longer, so it is purging it.
2) the owner of lockres A is node B, so node A is sending de-ref message
to node B.
3) at this time, node B crashed. node C becomes the recovery master. it recovers
lockres A(because the master is the dead node B).
4) node A migrated lockres A to node C with a refbit there.
5) node A failed to send de-ref message to node B because it crashed. The failure
is ignored. no other action is done for lockres A any more.

For mormal, re-send the deref message to it to recovery master can fix it. Well,
ignoring the failure of deref to the original master and not recovering the lockres
to recovery master has the same effect. And the later is simpler.

Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Acked-by: Srinivas Eeda <srinivas.eeda@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Joel Becker <joel.becker@oracle.com>

1 files changed, 10 insertions, 12 deletions

diff --git a/fs/ocfs2/dlm/dlmrecovery.c b/fs/ocfs2/dlm/dlmrecovery.c
index 9dfaac73b36da4..aaaffbcbe9163f 100644
--- a/fs/ocfs2/dlm/dlmrecovery.c
+++ b/fs/ocfs2/dlm/dlmrecovery.c
@@ -1997,6 +1997,8 @@ void dlm_move_lockres_to_recovery_list(struct dlm_ctxt *dlm,
 	struct list_head *queue;
 	struct dlm_lock *lock, *next;
 
+	assert_spin_locked(&dlm->spinlock);
+	assert_spin_locked(&res->spinlock);
 	res->state |= DLM_LOCK_RES_RECOVERING;
 	if (!list_empty(&res->recovering)) {
 		mlog(0,
@@ -2326,19 +2328,15 @@ static void dlm_do_local_recovery_cleanup(struct dlm_ctxt *dlm, u8 dead_node)
 			/* zero the lvb if necessary */
 			dlm_revalidate_lvb(dlm, res, dead_node);
 			if (res->owner == dead_node) {
-				if (res->state & DLM_LOCK_RES_DROPPING_REF)
-					mlog(0, "%s:%.*s: owned by "
-					     "dead node %u, this node was "
-					     "dropping its ref when it died. "
-					     "continue, dropping the flag.\n",
-					     dlm->name, res->lockname.len,
-					     res->lockname.name, dead_node);
-
-				/* the wake_up for this will happen when the
-				 * RECOVERING flag is dropped later */
-				res->state &= ~DLM_LOCK_RES_DROPPING_REF;
+				if (res->state & DLM_LOCK_RES_DROPPING_REF) {
+					mlog(ML_NOTICE, "Ignore %.*s for "
+					     "recovery as it is being freed\n",
+					     res->lockname.len,
+					     res->lockname.name);
+				} else
+					dlm_move_lockres_to_recovery_list(dlm,
+									  res);
 
-				dlm_move_lockres_to_recovery_list(dlm, res);
 			} else if (res->owner == dlm->node_num) {
 				dlm_free_dead_locks(dlm, res, dead_node);
 				__dlm_lockres_calc_usage(dlm, res);