dlm: recover nodes that are removed and re-added

If a node is removed from a lockspace, and then added back before the
dlm is notified of the removal, the dlm will not detect the removal
and won't clear the old state from the node.  This is fixed by using a
list of added nodes so the membership recovery can detect when a newly
added node is already in the member list.

Signed-off-by: David Teigland <teigland@redhat.com>

1 files changed, 29 insertions, 5 deletions

diff --git a/fs/dlm/member.c b/fs/dlm/member.c
index fa17f5a..26133f0 100644
--- a/fs/dlm/member.c
+++ b/fs/dlm/member.c
@@ -210,6 +210,23 @@ int dlm_recover_members(struct dlm_ls *ls, struct dlm_recover *rv, int *neg_out)
 		}
 	}
 
+	/* Add an entry to ls_nodes_gone for members that were removed and
+	   then added again, so that previous state for these nodes will be
+	   cleared during recovery. */
+
+	for (i = 0; i < rv->new_count; i++) {
+		if (!dlm_is_member(ls, rv->new[i]))
+			continue;
+		log_debug(ls, "new nodeid %d is a re-added member", rv->new[i]);
+
+		memb = kzalloc(sizeof(struct dlm_member), GFP_KERNEL);
+		if (!memb)
+			return -ENOMEM;
+		memb->nodeid = rv->new[i];
+		list_add_tail(&memb->list, &ls->ls_nodes_gone);
+		neg++;
+	}
+
 	/* add new members to ls_nodes */
 
 	for (i = 0; i < rv->node_count; i++) {
@@ -314,15 +331,16 @@ int dlm_ls_stop(struct dlm_ls *ls)
 int dlm_ls_start(struct dlm_ls *ls)
 {
 	struct dlm_recover *rv = NULL, *rv_old;
-	int *ids = NULL;
-	int error, count;
+	int *ids = NULL, *new = NULL;
+	int error, ids_count = 0, new_count = 0;
 
 	rv = kzalloc(sizeof(struct dlm_recover), GFP_KERNEL);
 	if (!rv)
 		return -ENOMEM;
 
-	error = count = dlm_nodeid_list(ls->ls_name, &ids);
-	if (error <= 0)
+	error = dlm_nodeid_list(ls->ls_name, &ids, &ids_count,
+				&new, &new_count);
+	if (error < 0)
 		goto fail;
 
 	spin_lock(&ls->ls_recover_lock);
@@ -337,14 +355,19 @@ int dlm_ls_start(struct dlm_ls *ls)
 	}
 
 	rv->nodeids = ids;
-	rv->node_count = count;
+	rv->node_count = ids_count;
+	rv->new = new;
+	rv->new_count = new_count;
 	rv->seq = ++ls->ls_recover_seq;
 	rv_old = ls->ls_recover_args;
 	ls->ls_recover_args = rv;
 	spin_unlock(&ls->ls_recover_lock);
 
 	if (rv_old) {
+		log_error(ls, "unused recovery %llx %d",
+			  (unsigned long long)rv_old->seq, rv_old->node_count);
 		kfree(rv_old->nodeids);
+		kfree(rv_old->new);
 		kfree(rv_old);
 	}
 
@@ -354,6 +377,7 @@ int dlm_ls_start(struct dlm_ls *ls)
  fail:
 	kfree(rv);
 	kfree(ids);
+	kfree(new);
 	return error;
 }