/*

 * CDDL HEADER START

 *

 * The contents of this file are subject to the terms of the

 * Common Development and Distribution License (the "License").

 * You may not use this file except in compliance with the License.

 *

 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE

 * or http://www.opensolaris.org/os/licensing.

 * See the License for the specific language governing permissions

 * and limitations under the License.

 *

 * When distributing Covered Code, include this CDDL HEADER in each

 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.

 * If applicable, add the following below this CDDL HEADER, with the

 * fields enclosed by brackets "[]" replaced with your own identifying

 * information: Portions Copyright [yyyy] [name of copyright owner]

 *

 * CDDL HEADER END

 */

/*

 * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.

 * Use is subject to license terms.

 */

#include <sys/zfs_context.h>

#include <sys/spa.h>

#include <sys/vdev_impl.h>

#include <sys/zio.h>

#include <sys/fs/zfs.h>

/*

 * Virtual device vector for the pool's root vdev.

 */

/*

 * We should be able to tolerate one failure with absolutely no damage

 * to our metadata.  Two failures will take out space maps, a bunch of

 * indirect block trees, meta dnodes, dnodes, etc.  Probably not a happy

 * place to live.  When we get smarter, we can liberalize this policy.

 * e.g. If we haven't lost two consecutive top-level vdevs, then we are

 * probably fine.  Adding bean counters during alloc/free can make this

 * future guesswork more accurate.

 */

static int

too_many_errors(vdev_t *vd, int numerrors)

{

	ASSERT3U(numerrors, <=, vd->vdev_children);

	return (numerrors > 0);

}

static int

vdev_root_open(vdev_t *vd, uint64_t *asize, uint64_t *ashift)

{

	int lasterror = 0;

	int numerrors = 0;

	if (vd->vdev_children == 0) {

		vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;

		return (EINVAL);

	}

	vdev_open_children(vd);

	for (int c = 0; c < vd->vdev_children; c++) {

		vdev_t *cvd = vd->vdev_child[c];

		if (cvd->vdev_open_error && !cvd->vdev_islog) {

			lasterror = cvd->vdev_open_error;

			numerrors++;

		}

	}

	if (too_many_errors(vd, numerrors)) {

		vd->vdev_stat.vs_aux = VDEV_AUX_NO_REPLICAS;

		return (lasterror);

	}

	*asize = 0;

	*ashift = 0;

	return (0);

}

static void

vdev_root_close(vdev_t *vd)

{

	for (int c = 0; c < vd->vdev_children; c++)

		vdev_close(vd->vdev_child[c]);

}

static void

vdev_root_state_change(vdev_t *vd, int faulted, int degraded)

{

	if (too_many_errors(vd, faulted)) {

		vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,

		    VDEV_AUX_NO_REPLICAS);

	} else if (degraded) {

		vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, VDEV_AUX_NONE);

	} else {

		vdev_set_state(vd, B_FALSE, VDEV_STATE_HEALTHY, VDEV_AUX_NONE);

	}

}

vdev_ops_t vdev_root_ops = {

	vdev_root_open,

	vdev_root_close,

	vdev_default_asize,

	NULL,			/* io_start - not applicable to the root */

	NULL,			/* io_done - not applicable to the root */

	vdev_root_state_change,

	NULL,

	NULL,

	VDEV_TYPE_ROOT,		/* name of this vdev type */

	B_FALSE			/* not a leaf vdev */

};