dlmrecovery.c

linux 内核源代码

	spin_lock(&dlm->spinlock);
	BUG_ON(!(dlm->reco.state & DLM_RECO_STATE_ACTIVE));
	dlm->reco.state &= ~DLM_RECO_STATE_ACTIVE;
	spin_unlock(&dlm->spinlock);
	wake_up(&dlm->reco.event);
}

static int dlm_do_recovery(struct dlm_ctxt *dlm)
{
	int status = 0;
	int ret;

	spin_lock(&dlm->spinlock);

	/* check to see if the new master has died */
	if (dlm->reco.new_master != O2NM_INVALID_NODE_NUM &&
	    test_bit(dlm->reco.new_master, dlm->recovery_map)) {
		mlog(0, "new master %u died while recovering %u!\n",
		     dlm->reco.new_master, dlm->reco.dead_node);
		/* unset the new_master, leave dead_node */
		dlm_set_reco_master(dlm, O2NM_INVALID_NODE_NUM);
	}

	/* select a target to recover */
	if (dlm->reco.dead_node == O2NM_INVALID_NODE_NUM) {
		int bit;

		bit = find_next_bit (dlm->recovery_map, O2NM_MAX_NODES+1, 0);
		if (bit >= O2NM_MAX_NODES || bit < 0)
			dlm_set_reco_dead_node(dlm, O2NM_INVALID_NODE_NUM);
		else
			dlm_set_reco_dead_node(dlm, bit);
	} else if (!test_bit(dlm->reco.dead_node, dlm->recovery_map)) {
		/* BUG? */
		mlog(ML_ERROR, "dead_node %u no longer in recovery map!\n",
		     dlm->reco.dead_node);
		dlm_set_reco_dead_node(dlm, O2NM_INVALID_NODE_NUM);
	}

	if (dlm->reco.dead_node == O2NM_INVALID_NODE_NUM) {
		// mlog(0, "nothing to recover!  sleeping now!\n");
		spin_unlock(&dlm->spinlock);
		/* return to main thread loop and sleep. */
		return 0;
	}
	mlog(0, "%s(%d):recovery thread found node %u in the recovery map!\n",
	     dlm->name, task_pid_nr(dlm->dlm_reco_thread_task),
	     dlm->reco.dead_node);
	spin_unlock(&dlm->spinlock);

	/* take write barrier */
	/* (stops the list reshuffling thread, proxy ast handling) */
	dlm_begin_recovery(dlm);

	if (dlm->reco.new_master == dlm->node_num)
		goto master_here;

	if (dlm->reco.new_master == O2NM_INVALID_NODE_NUM) {
		/* choose a new master, returns 0 if this node
		 * is the master, -EEXIST if it's another node.
		 * this does not return until a new master is chosen
		 * or recovery completes entirely. */
		ret = dlm_pick_recovery_master(dlm);
		if (!ret) {
			/* already notified everyone.  go. */
			goto master_here;
		}
		mlog(0, "another node will master this recovery session.\n");
	}
	mlog(0, "dlm=%s (%d), new_master=%u, this node=%u, dead_node=%u\n",
	     dlm->name, task_pid_nr(dlm->dlm_reco_thread_task), dlm->reco.new_master,
	     dlm->node_num, dlm->reco.dead_node);

	/* it is safe to start everything back up here
	 * because all of the dead node's lock resources
	 * have been marked as in-recovery */
	dlm_end_recovery(dlm);

	/* sleep out in main dlm_recovery_thread loop. */
	return 0;

master_here:
	mlog(0, "(%d) mastering recovery of %s:%u here(this=%u)!\n",
	     task_pid_nr(dlm->dlm_reco_thread_task),
	     dlm->name, dlm->reco.dead_node, dlm->node_num);

	status = dlm_remaster_locks(dlm, dlm->reco.dead_node);
	if (status < 0) {
		/* we should never hit this anymore */
		mlog(ML_ERROR, "error %d remastering locks for node %u, "
		     "retrying.\n", status, dlm->reco.dead_node);
		/* yield a bit to allow any final network messages
		 * to get handled on remaining nodes */
		msleep(100);
	} else {
		/* success!  see if any other nodes need recovery */
		mlog(0, "DONE mastering recovery of %s:%u here(this=%u)!\n",
		     dlm->name, dlm->reco.dead_node, dlm->node_num);
		dlm_reset_recovery(dlm);
	}
	dlm_end_recovery(dlm);

	/* continue and look for another dead node */
	return -EAGAIN;
}

static int dlm_remaster_locks(struct dlm_ctxt *dlm, u8 dead_node)
{
	int status = 0;
	struct dlm_reco_node_data *ndata;
	int all_nodes_done;
	int destroy = 0;
	int pass = 0;

	do {
		/* we have become recovery master.  there is no escaping
		 * this, so just keep trying until we get it. */
		status = dlm_init_recovery_area(dlm, dead_node);
		if (status < 0) {
			mlog(ML_ERROR, "%s: failed to alloc recovery area, "
			     "retrying\n", dlm->name);
			msleep(1000);
		}
	} while (status != 0);

	/* safe to access the node data list without a lock, since this
	 * process is the only one to change the list */
	list_for_each_entry(ndata, &dlm->reco.node_data, list) {
		BUG_ON(ndata->state != DLM_RECO_NODE_DATA_INIT);
		ndata->state = DLM_RECO_NODE_DATA_REQUESTING;

		mlog(0, "requesting lock info from node %u\n",
		     ndata->node_num);

		if (ndata->node_num == dlm->node_num) {
			ndata->state = DLM_RECO_NODE_DATA_DONE;
			continue;
		}

		do {
			status = dlm_request_all_locks(dlm, ndata->node_num,
						       dead_node);
			if (status < 0) {
				mlog_errno(status);
				if (dlm_is_host_down(status)) {
					/* node died, ignore it for recovery */
					status = 0;
					ndata->state = DLM_RECO_NODE_DATA_DEAD;
					/* wait for the domain map to catch up
					 * with the network state. */
					wait_event_timeout(dlm->dlm_reco_thread_wq,
							   dlm_is_node_dead(dlm,
								ndata->node_num),
							   msecs_to_jiffies(1000));
					mlog(0, "waited 1 sec for %u, "
					     "dead? %s\n", ndata->node_num,
					     dlm_is_node_dead(dlm, ndata->node_num) ?
					     "yes" : "no");
				} else {
					/* -ENOMEM on the other node */
					mlog(0, "%s: node %u returned "
					     "%d during recovery, retrying "
					     "after a short wait\n",
					     dlm->name, ndata->node_num,
					     status);
					msleep(100);
				}
			}
		} while (status != 0);

		spin_lock(&dlm_reco_state_lock);
		switch (ndata->state) {
			case DLM_RECO_NODE_DATA_INIT:
			case DLM_RECO_NODE_DATA_FINALIZE_SENT:
			case DLM_RECO_NODE_DATA_REQUESTED:
				BUG();
				break;
			case DLM_RECO_NODE_DATA_DEAD:
				mlog(0, "node %u died after requesting "
				     "recovery info for node %u\n",
				     ndata->node_num, dead_node);
				/* fine.  don't need this node's info.
				 * continue without it. */
				break;
			case DLM_RECO_NODE_DATA_REQUESTING:
				ndata->state = DLM_RECO_NODE_DATA_REQUESTED;
				mlog(0, "now receiving recovery data from "
				     "node %u for dead node %u\n",
				     ndata->node_num, dead_node);
				break;
			case DLM_RECO_NODE_DATA_RECEIVING:
				mlog(0, "already receiving recovery data from "
				     "node %u for dead node %u\n",
				     ndata->node_num, dead_node);
				break;
			case DLM_RECO_NODE_DATA_DONE:
				mlog(0, "already DONE receiving recovery data "
				     "from node %u for dead node %u\n",
				     ndata->node_num, dead_node);
				break;
		}
		spin_unlock(&dlm_reco_state_lock);
	}

	mlog(0, "done requesting all lock info\n");

	/* nodes should be sending reco data now
	 * just need to wait */

	while (1) {
		/* check all the nodes now to see if we are
		 * done, or if anyone died */
		all_nodes_done = 1;
		spin_lock(&dlm_reco_state_lock);
		list_for_each_entry(ndata, &dlm->reco.node_data, list) {
			mlog(0, "checking recovery state of node %u\n",
			     ndata->node_num);
			switch (ndata->state) {
				case DLM_RECO_NODE_DATA_INIT:
				case DLM_RECO_NODE_DATA_REQUESTING:
					mlog(ML_ERROR, "bad ndata state for "
					     "node %u: state=%d\n",
					     ndata->node_num, ndata->state);
					BUG();
					break;
				case DLM_RECO_NODE_DATA_DEAD:
					mlog(0, "node %u died after "
					     "requesting recovery info for "
					     "node %u\n", ndata->node_num,
					     dead_node);
					break;
				case DLM_RECO_NODE_DATA_RECEIVING:
				case DLM_RECO_NODE_DATA_REQUESTED:
					mlog(0, "%s: node %u still in state %s\n",
					     dlm->name, ndata->node_num,
					     ndata->state==DLM_RECO_NODE_DATA_RECEIVING ?
					     "receiving" : "requested");
					all_nodes_done = 0;
					break;
				case DLM_RECO_NODE_DATA_DONE:
					mlog(0, "%s: node %u state is done\n",
					     dlm->name, ndata->node_num);
					break;
				case DLM_RECO_NODE_DATA_FINALIZE_SENT:
					mlog(0, "%s: node %u state is finalize\n",
					     dlm->name, ndata->node_num);
					break;
			}
		}
		spin_unlock(&dlm_reco_state_lock);

		mlog(0, "pass #%d, all_nodes_done?: %s\n", ++pass,
		     all_nodes_done?"yes":"no");
		if (all_nodes_done) {
			int ret;

			/* all nodes are now in DLM_RECO_NODE_DATA_DONE state
	 		 * just send a finalize message to everyone and
	 		 * clean up */
			mlog(0, "all nodes are done! send finalize\n");
			ret = dlm_send_finalize_reco_message(dlm);
			if (ret < 0)
				mlog_errno(ret);

			spin_lock(&dlm->spinlock);
			dlm_finish_local_lockres_recovery(dlm, dead_node,
							  dlm->node_num);
			spin_unlock(&dlm->spinlock);
			mlog(0, "should be done with recovery!\n");

			mlog(0, "finishing recovery of %s at %lu, "
			     "dead=%u, this=%u, new=%u\n", dlm->name,
			     jiffies, dlm->reco.dead_node,
			     dlm->node_num, dlm->reco.new_master);
			destroy = 1;
			status = 0;
			/* rescan everything marked dirty along the way */
			dlm_kick_thread(dlm, NULL);
			break;
		}
		/* wait to be signalled, with periodic timeout
		 * to check for node death */
		wait_event_interruptible_timeout(dlm->dlm_reco_thread_wq,
					 kthread_should_stop(),
					 msecs_to_jiffies(DLM_RECO_THREAD_TIMEOUT_MS));

	}

	if (destroy)
		dlm_destroy_recovery_area(dlm, dead_node);

	mlog_exit(status);
	return status;
}

static int dlm_init_recovery_area(struct dlm_ctxt *dlm, u8 dead_node)
{
	int num=0;
	struct dlm_reco_node_data *ndata;

	spin_lock(&dlm->spinlock);
	memcpy(dlm->reco.node_map, dlm->domain_map, sizeof(dlm->domain_map));
	/* nodes can only be removed (by dying) after dropping
	 * this lock, and death will be trapped later, so this should do */
	spin_unlock(&dlm->spinlock);

	while (1) {
		num = find_next_bit (dlm->reco.node_map, O2NM_MAX_NODES, num);
		if (num >= O2NM_MAX_NODES) {
			break;
		}
		BUG_ON(num == dead_node);

		ndata = kzalloc(sizeof(*ndata), GFP_NOFS);
		if (!ndata) {
			dlm_destroy_recovery_area(dlm, dead_node);
			return -ENOMEM;
		}
		ndata->node_num = num;
		ndata->state = DLM_RECO_NODE_DATA_INIT;
		spin_lock(&dlm_reco_state_lock);
		list_add_tail(&ndata->list, &dlm->reco.node_data);
		spin_unlock(&dlm_reco_state_lock);
		num++;
	}

	return 0;
}

static void dlm_destroy_recovery_area(struct dlm_ctxt *dlm, u8 dead_node)
{
	struct dlm_reco_node_data *ndata, *next;
	LIST_HEAD(tmplist);

	spin_lock(&dlm_reco_state_lock);
	list_splice_init(&dlm->reco.node_data, &tmplist);
	spin_unlock(&dlm_reco_state_lock);

	list_for_each_entry_safe(ndata, next, &tmplist, list) {
		list_del_init(&ndata->list);
		kfree(ndata);
	}
}

static int dlm_request_all_locks(struct dlm_ctxt *dlm, u8 request_from,
				 u8 dead_node)
{
	struct dlm_lock_request lr;
	enum dlm_status ret;

	mlog(0, "\n");


	mlog(0, "dlm_request_all_locks: dead node is %u, sending request "
		  "to %u\n", dead_node, request_from);

	memset(&lr, 0, sizeof(lr));
	lr.node_idx = dlm->node_num;
	lr.dead_node = dead_node;

	// send message
	ret = DLM_NOLOCKMGR;
	ret = o2net_send_message(DLM_LOCK_REQUEST_MSG, dlm->key,
				 &lr, sizeof(lr), request_from, NULL);

	/* negative status is handled by caller */
	if (ret < 0)
		mlog_errno(ret);

	// return from here, then
	// sleep until all received or error
	return ret;

}

int dlm_request_all_locks_handler(struct o2net_msg *msg, u32 len, void *data,
				  void **ret_data)
{
	struct dlm_ctxt *dlm = data;
	struct dlm_lock_request *lr = (struct dlm_lock_request *)msg->buf;
	char *buf = NULL;
	struct dlm_work_item *item = NULL;

	if (!dlm_grab(dlm))
		return -EINVAL;

	if (lr->dead_node != dlm->reco.dead_node) {
		mlog(ML_ERROR, "%s: node %u sent dead_node=%u, but local "
		     "dead_node is %u\n", dlm->name, lr->node_idx,
		     lr->dead_node, dlm->reco.dead_node);
		dlm_print_reco_node_status(dlm);
		/* this is a hack */
		dlm_put(dlm);
		return -ENOMEM;
	}
	BUG_ON(lr->dead_node != dlm->reco.dead_node);

	item = kzalloc(sizeof(*item), GFP_NOFS);
	if (!item) {
		dlm_put(dlm);
		return -ENOMEM;
	}

	/* this will get freed by dlm_request_all_locks_worker */
	buf = (char *) __get_free_page(GFP_NOFS);
	if (!buf) {
		kfree(item);
		dlm_put(dlm);
		return -ENOMEM;
	}

	/* queue up work for dlm_request_all_locks_worker */
	dlm_grab(dlm);  /* get an extra ref for the work item */
	dlm_init_work_item(dlm, item, dlm_request_all_locks_worker, buf);
	item->u.ral.reco_master = lr->node_idx;
	item->u.ral.dead_node = lr->dead_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);

	dlm_put(dlm);
	return 0;
}

static void dlm_request_all_locks_worker(struct dlm_work_item *item, void *data)
{
	struct dlm_migratable_lockres *mres;
	struct dlm_lock_resource *res;
	struct dlm_ctxt *dlm;
	LIST_HEAD(resources);
	int ret;
	u8 dead_node, reco_master;
	int skip_all_done = 0;

	dlm = item->dlm;
	dead_node = item->u.ral.dead_node;
	reco_master = item->u.ral.reco_master;
	mres = (struct dlm_migratable_lockres *)data;