path: root/fs/dlm/recover.c

/******************************************************************************
*******************************************************************************
**
**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
**  Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
**
**  This copyrighted material is made available to anyone wishing to use,
**  modify, copy, or redistribute it subject to the terms and conditions
**  of the GNU General Public License v.2.
**
*******************************************************************************
******************************************************************************/

#include "dlm_internal.h"
#include "lockspace.h"
#include "dir.h"
#include "config.h"
#include "ast.h"
#include "memory.h"
#include "rcom.h"
#include "lock.h"
#include "lowcomms.h"
#include "member.h"
#include "recover.h"


/*
 * Recovery waiting routines: these functions wait for a particular reply from
 * a remote node, or for the remote node to report a certain status.  They need
 * to abort if the lockspace is stopped indicating a node has failed (perhaps
 * the one being waited for).
 */

/*
 * Wait until given function returns non-zero or lockspace is stopped
 * (LS_RECOVERY_STOP set due to failure of a node in ls_nodes).  When another
 * function thinks it could have completed the waited-on task, they should wake
 * up ls_wait_general to get an immediate response rather than waiting for the
 * timeout.  This uses a timeout so it can check periodically if the wait
 * should abort due to node failure (which doesn't cause a wake_up).
 * This should only be called by the dlm_recoverd thread.
 */

int dlm_wait_function(struct dlm_ls *ls, int (*testfn) (struct dlm_ls *ls))
{
	int error = 0;
	int rv;

	while (1) {
		rv = wait_event_timeout(ls->ls_wait_general,
					testfn(ls) || dlm_recovery_stopped(ls),
					dlm_config.ci_recover_timer * HZ);
		if (rv)
			break;
	}

	if (dlm_recovery_stopped(ls)) {
		log_debug(ls, "dlm_wait_function aborted");
		error = -EINTR;
	}
	return error;
}

/*
 * An efficient way for all nodes to wait for all others to have a certain
 * status.  The node with the lowest nodeid polls all the others for their
 * status (wait_status_all) and all the others poll the node with the low id
 * for its accumulated result (wait_status_low).  When all nodes have set
 * status flag X, then status flag X_ALL will be set on the low nodeid.
 */

uint32_t dlm_recover_status(struct dlm_ls *ls)
{
	uint32_t status;
	spin_lock(&ls->ls_recover_lock);
	status = ls->ls_recover_status;
	spin_unlock(&ls->ls_recover_lock);
	return status;
}

static void _set_recover_status(struct dlm_ls *ls, uint32_t status)
{
	ls->ls_recover_status |= status;
}

void dlm_set_recover_status(struct dlm_ls *ls, uint32_t status)
{
	spin_lock(&ls->ls_recover_lock);
	_set_recover_status(ls, status);
	spin_unlock(&ls->ls_recover_lock);
}

static int wait_status_all(struct dlm_ls *ls, uint32_t wait_status,
			   int save_slots)
{
	struct dlm_rcom *rc = ls->ls_recover_buf;
	struct dlm_member *memb;
	int error = 0, delay;

	list_for_each_entry(memb, &ls->ls_nodes, list) {
		delay = 0;
		for (;;) {
			if (dlm_recovery_stopped(ls)) {
				error = -EINTR;
				goto out;
			}

			error = dlm_rcom_status(ls, memb->nodeid, 0);
			if (error)
				goto out;

			if (save_slots)
				dlm_slot_save(ls, rc, memb);

			if (rc->rc_result & wait_status)
				break;
			if (delay < 1000)
				delay += 20;
			msleep(delay);
		}
	}
 out:
	return error;
}

static int wait_status_low(struct dlm_ls *ls, uint32_t wait_status,
			   uint32_t status_flags)
{
	struct dlm_rcom *rc = ls->ls_recover_buf;
	int error = 0, delay = 0, nodeid = ls->ls_low_nodeid;

	for (;;) {
		if (dlm_recovery_stopped(ls)) {
			error = -EINTR;
			goto out;
		}

		error = dlm_rcom_status(ls, nodeid, status_flags);
		if (error)
			break;

		if (rc->rc_result & wait_status)
			break;
		if (delay < 1000)
			delay += 20;
		msleep(delay);
	}
 out:
	return error;
}

static int wait_status(struct dlm_ls *ls, uint32_t status)
{
	uint32_t status_all = status << 1;
	int error;

	if (ls->ls_low_nodeid == dlm_our_nodeid()) {
		error = wait_status_all(ls, status, 0);
		if (!error)
			dlm_set_recover_status(ls, status_all);
	} else
		error = wait_status_low(ls, status_all, 0);

	return error;
}

int dlm_recover_members_wait(struct dlm_ls *ls)
{
	struct dlm_member *memb;
	struct dlm_slot *slots;
	int num_slots, slots_size;
	int error, rv;
	uint32_t gen;

	list_for_each_entry(memb, &ls->ls_nodes, list) {
		memb->slot = -1;
		memb->generation = 0;
	}

	if (ls->ls_low_nodeid == dlm_our_nodeid())