LU-5092 nodemap: add structure to hold nodemap config

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

diff --git a/lustre/ptlrpc/nodemap_member.c b/lustre/ptlrpc/nodemap_member.c
index 81a0980..d4ffc23 100644 (file)
--- a/lustre/ptlrpc/nodemap_member.c
+++ b/lustre/ptlrpc/nodemap_member.c
@@ -126,9 +126,6 @@ static void nm_member_exp_revoke(struct obd_export *exp)
        ldlm_revoke_export_locks(exp);
 }
 
-/* Mutex used to serialize calls to reclassify_nodemap_lock */
-DEFINE_MUTEX(reclassify_nodemap_lock);
-
 /**
  * Reclassify the members of a nodemap after range changes or activation.
  * This function reclassifies the members of a nodemap based on the member
@@ -136,15 +133,8 @@ DEFINE_MUTEX(reclassify_nodemap_lock);
  * classified as being part of this nodemap are moved to the nodemap whose
  * NID ranges contain the export's NID, and their locks are revoked.
  *
- * Calls to this function are serialized due to a potential deadlock: Say there
- * is a nodemap A and a nodemap B that both need to reclassify their members.
- * If there is a member in nodemap A that should be in nodemap B, reclassify
- * will attempt to add the member to nodemap B. If nodemap B is also
- * reclassifying its members, then its hash is locked and nodemap A's attempt
- * to add will block and wait for nodemap B's reclassify to finish. If
- * nodemap B's reclassify then attempts to reclassify a member that should be
- * in nodemap A, it will also try add the member to nodemap A's locked hash,
- * causing a deadlock.
+ * Callers should hold the active_config_lock and active_config
+ * nmc_range_tree_lock.
  *
  * \param      nodemap         nodemap with members to reclassify
  */
@@ -154,17 +144,13 @@ void nm_member_reclassify_nodemap(struct lu_nodemap *nodemap)
        struct obd_export *tmp;
        struct lu_nodemap *new_nodemap;
 
-       /* reclassify only one nodemap at a time to avoid deadlock */
-       mutex_lock(&reclassify_nodemap_lock);
        mutex_lock(&nodemap->nm_member_list_lock);
        list_for_each_entry_safe(exp, tmp, &nodemap->nm_member_list,
                                 exp_target_data.ted_nodemap_member) {
                lnet_nid_t nid = exp->exp_connection->c_peer.nid;
 
-               /* nodemap_classify_nid requires range tree lock */
-               read_lock(&nm_range_tree_lock);
+               /* nodemap_classify_nid requires nmc_range_tree_lock */
                new_nodemap = nodemap_classify_nid(nid);
-               read_unlock(&nm_range_tree_lock);
                if (new_nodemap != nodemap) {
                        /* don't use member_del because ted_nodemap
                         * should never be null
@@ -179,10 +165,13 @@ void nm_member_reclassify_nodemap(struct lu_nodemap *nodemap)
                        mutex_unlock(&new_nodemap->nm_member_list_lock);
                        nm_member_exp_revoke(exp);
                }
+
+               /* This put won't destroy new_nodemap because any nodemap_del
+                * call done on new_nodemap blocks on our active_config_lock
+                */
                nodemap_putref(new_nodemap);
        }
        mutex_unlock(&nodemap->nm_member_list_lock);
-       mutex_unlock(&reclassify_nodemap_lock);
 }
 
 /**