+/*
+ * DLM_DEREF_LOCKRES_MSG
+ */
+
+int dlm_drop_lockres_ref(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
+{
+ struct dlm_deref_lockres deref;
+ int ret = 0, r;
+ const char *lockname;
+ unsigned int namelen;
+
+ lockname = res->lockname.name;
+ namelen = res->lockname.len;
+ BUG_ON(namelen > O2NM_MAX_NAME_LEN);
+
+ mlog(0, "%s:%.*s: sending deref to %d\n",
+ dlm->name, namelen, lockname, res->owner);
+ memset(&deref, 0, sizeof(deref));
+ deref.node_idx = dlm->node_num;
+ deref.namelen = namelen;
+ memcpy(deref.name, lockname, namelen);
+
+ ret = o2net_send_message(DLM_DEREF_LOCKRES_MSG, dlm->key,
+ &deref, sizeof(deref), res->owner, &r);
+ if (ret < 0)
+ mlog_errno(ret);
+ else if (r < 0) {
+ /* BAD. other node says I did not have a ref. */
+ mlog(ML_ERROR,"while dropping ref on %s:%.*s "
+ "(master=%u) got %d.\n", dlm->name, namelen,
+ lockname, res->owner, r);
+ dlm_print_one_lock_resource(res);
+ BUG();
+ }
+ return ret;
+}
+
+int dlm_deref_lockres_handler(struct o2net_msg *msg, u32 len, void *data,
+ void **ret_data)
+{
+ struct dlm_ctxt *dlm = data;
+ struct dlm_deref_lockres *deref = (struct dlm_deref_lockres *)msg->buf;
+ struct dlm_lock_resource *res = NULL;
+ char *name;
+ unsigned int namelen;
+ int ret = -EINVAL;
+ u8 node;
+ unsigned int hash;
+ struct dlm_work_item *item;
+ int cleared = 0;
+ int dispatch = 0;
+
+ if (!dlm_grab(dlm))
+ return 0;
+
+ name = deref->name;
+ namelen = deref->namelen;
+ node = deref->node_idx;
+
+ if (namelen > DLM_LOCKID_NAME_MAX) {
+ mlog(ML_ERROR, "Invalid name length!");
+ goto done;
+ }
+ if (deref->node_idx >= O2NM_MAX_NODES) {
+ mlog(ML_ERROR, "Invalid node number: %u\n", node);
+ goto done;
+ }
+
+ hash = dlm_lockid_hash(name, namelen);
+
+ spin_lock(&dlm->spinlock);
+ res = __dlm_lookup_lockres_full(dlm, name, namelen, hash);
+ if (!res) {
+ spin_unlock(&dlm->spinlock);
+ mlog(ML_ERROR, "%s:%.*s: bad lockres name\n",
+ dlm->name, namelen, name);
+ goto done;
+ }
+ spin_unlock(&dlm->spinlock);
+
+ spin_lock(&res->spinlock);
+ if (res->state & DLM_LOCK_RES_SETREF_INPROG)
+ dispatch = 1;
+ else {
+ BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF);
+ if (test_bit(node, res->refmap)) {
+ dlm_lockres_clear_refmap_bit(node, res);
+ cleared = 1;
+ }
+ }
+ spin_unlock(&res->spinlock);
+
+ if (!dispatch) {
+ if (cleared)
+ dlm_lockres_calc_usage(dlm, res);
+ else {
+ mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref "
+ "but it is already dropped!\n", dlm->name,
+ res->lockname.len, res->lockname.name, node);
+ __dlm_print_one_lock_resource(res);
+ }
+ ret = 0;
+ goto done;
+ }
+
+ item = kzalloc(sizeof(*item), GFP_NOFS);
+ if (!item) {
+ ret = -ENOMEM;
+ mlog_errno(ret);
+ goto done;
+ }
+
+ dlm_init_work_item(dlm, item, dlm_deref_lockres_worker, NULL);
+ item->u.dl.deref_res = res;
+ item->u.dl.deref_node = node;
+
+ spin_lock(&dlm->work_lock);
+ list_add_tail(&item->list, &dlm->work_list);
+ spin_unlock(&dlm->work_lock);
+
+ queue_work(dlm->dlm_worker, &dlm->dispatched_work);
+ return 0;
+
+done:
+ if (res)
+ dlm_lockres_put(res);
+ dlm_put(dlm);
+
+ return ret;
+}
+
+static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data)
+{
+ struct dlm_ctxt *dlm;
+ struct dlm_lock_resource *res;
+ u8 node;
+ u8 cleared = 0;
+
+ dlm = item->dlm;
+ res = item->u.dl.deref_res;
+ node = item->u.dl.deref_node;
+
+ spin_lock(&res->spinlock);
+ BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF);
+ if (test_bit(node, res->refmap)) {
+ __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG);
+ dlm_lockres_clear_refmap_bit(node, res);
+ cleared = 1;
+ }
+ spin_unlock(&res->spinlock);
+
+ if (cleared) {
+ mlog(0, "%s:%.*s node %u ref dropped in dispatch\n",
+ dlm->name, res->lockname.len, res->lockname.name, node);
+ dlm_lockres_calc_usage(dlm, res);
+ } else {
+ mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref "
+ "but it is already dropped!\n", dlm->name,
+ res->lockname.len, res->lockname.name, node);
+ __dlm_print_one_lock_resource(res);
+ }
+
+ dlm_lockres_put(res);
+}
+
+/* Checks whether the lockres can be migrated. Returns 0 if yes, < 0
+ * if not. If 0, numlocks is set to the number of locks in the lockres.
+ */
+static int dlm_is_lockres_migrateable(struct dlm_ctxt *dlm,
+ struct dlm_lock_resource *res,
+ int *numlocks)
+{
+ int ret;
+ int i;
+ int count = 0;
+ struct list_head *queue;
+ struct dlm_lock *lock;
+
+ assert_spin_locked(&res->spinlock);
+
+ ret = -EINVAL;
+ if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
+ mlog(0, "cannot migrate lockres with unknown owner!\n");
+ goto leave;
+ }
+
+ if (res->owner != dlm->node_num) {
+ mlog(0, "cannot migrate lockres this node doesn't own!\n");
+ goto leave;
+ }
+
+ ret = 0;
+ queue = &res->granted;
+ for (i = 0; i < 3; i++) {
+ list_for_each_entry(lock, queue, list) {
+ ++count;
+ if (lock->ml.node == dlm->node_num) {
+ mlog(0, "found a lock owned by this node still "
+ "on the %s queue! will not migrate this "
+ "lockres\n", (i == 0 ? "granted" :
+ (i == 1 ? "converting" :
+ "blocked")));
+ ret = -ENOTEMPTY;
+ goto leave;
+ }
+ }
+ queue++;
+ }
+
+ *numlocks = count;
+ mlog(0, "migrateable lockres having %d locks\n", *numlocks);
+
+leave:
+ return ret;
+}