LU-4647 nodemap: fix problem with node reclassification

[fs/lustre-release.git] / lustre / ptlrpc / nodemap_member.c

diff --git a/lustre/ptlrpc/nodemap_member.c b/lustre/ptlrpc/nodemap_member.c
index 00459f1..a4e5063 100644 (file)
--- a/lustre/ptlrpc/nodemap_member.c
+++ b/lustre/ptlrpc/nodemap_member.c
@@ -220,7 +220,7 @@ int nm_member_add(struct lu_nodemap *nodemap, struct obd_export *exp)
        rc = cfs_hash_add_unique(nodemap->nm_member_hash, exp,
                                 &exp->exp_target_data.ted_nodemap_member);
 
-       if (rc == 0 )
+       if (rc == 0)
                class_export_get(exp);
        /* else -EALREADY - exp already in nodemap hash */
 
@@ -247,25 +247,33 @@ static int nm_member_reclassify_cb(cfs_hash_t *hs, cfs_hash_bd_t *bd,
                                   struct hlist_node *hnode, void *data)
 {
        struct obd_export       *exp;
+       struct lu_nodemap       *nodemap;
 
        exp = hlist_entry(hnode, struct obd_export,
                          exp_target_data.ted_nodemap_member);
        if (exp == NULL)
                goto out;
 
-       /* Call member add before del so exp->nodemap is never NULL. Must use
-        * bd_del_locked inside a cfs_hash callback. For those reasons, can't
-        * use member_del.
+       /* Must use bd_del_locked inside a cfs_hash callback, and exp->nodemap
+        * should never be NULL. For those reasons, can't use member_del.
         */
-       nodemap_add_member(exp->exp_connection->c_peer.nid, exp);
-       cfs_hash_bd_del_locked(hs, bd, hnode);
-       class_export_put(exp);
+       read_lock(&nm_range_tree_lock);
+       nodemap = nodemap_classify_nid(exp->exp_connection->c_peer.nid);
+       if (exp->exp_target_data.ted_nodemap != nodemap) {
+               cfs_hash_bd_del_locked(hs, bd, hnode);
+               exp->exp_target_data.ted_nodemap = nodemap;
+               cfs_hash_add_unique(nodemap->nm_member_hash, exp,
+                               &exp->exp_target_data.ted_nodemap_member);
+       }
+       read_unlock(&nm_range_tree_lock);
 
        nm_member_exp_revoke(exp);
 out:
        return 0;
 }
 
+DEFINE_MUTEX(reclassify_nodemap_lock);
+
 /**
  * Reclassify the members of a nodemap after range changes or activation,
  * based on the member export's NID and the nodemap's new NID ranges. Exports
@@ -277,9 +285,12 @@ out:
  */
 void nm_member_reclassify_nodemap(struct lu_nodemap *nodemap)
 {
+       /* reclassify only one nodemap at a time to avoid deadlock */
+       mutex_lock(&reclassify_nodemap_lock);
        cfs_hash_for_each_safe(nodemap->nm_member_hash,
                               nm_member_reclassify_cb,
                               NULL);
+       mutex_unlock(&reclassify_nodemap_lock);
 }
 
 static int nm_member_revoke_locks_cb(cfs_hash_t *hs, cfs_hash_bd_t *bd,