[mirror_zfs-debian.git] / module / zfs / vdev_root.c

/*
 * 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 */
};
Commit	Line	Data
34dc7c2f BB	1	/*
	2	* CDDL HEADER START
	3	*
	4	* The contents of this file are subject to the terms of the
	5	* Common Development and Distribution License (the "License").
	6	* You may not use this file except in compliance with the License.
	7	*
	8	* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
	9	* or http://www.opensolaris.org/os/licensing.
	10	* See the License for the specific language governing permissions
	11	* and limitations under the License.
	12	*
	13	* When distributing Covered Code, include this CDDL HEADER in each
	14	* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
	15	* If applicable, add the following below this CDDL HEADER, with the
	16	* fields enclosed by brackets "[]" replaced with your own identifying
	17	* information: Portions Copyright [yyyy] [name of copyright owner]
	18	*
	19	* CDDL HEADER END
	20	*/
	21	/*
428870ff	22	* Copyright 2010 Sun Microsystems, Inc. All rights reserved.
34dc7c2f BB	23	* Use is subject to license terms.
	24	*/
	25
34dc7c2f BB	26	#include <sys/zfs_context.h>
	27	#include <sys/spa.h>
	28	#include <sys/vdev_impl.h>
	29	#include <sys/zio.h>
	30	#include <sys/fs/zfs.h>
	31
	32	/*
	33	* Virtual device vector for the pool's root vdev.
	34	*/
	35
	36	/*
	37	* We should be able to tolerate one failure with absolutely no damage
	38	* to our metadata. Two failures will take out space maps, a bunch of
	39	* indirect block trees, meta dnodes, dnodes, etc. Probably not a happy
	40	* place to live. When we get smarter, we can liberalize this policy.
	41	* e.g. If we haven't lost two consecutive top-level vdevs, then we are
	42	* probably fine. Adding bean counters during alloc/free can make this
	43	* future guesswork more accurate.
	44	*/
	45	static int
	46	too_many_errors(vdev_t *vd, int numerrors)
	47	{
	48	ASSERT3U(numerrors, <=, vd->vdev_children);
b128c09f	49	return (numerrors > 0);
34dc7c2f BB	50	}
	51
	52	static int
	53	vdev_root_open(vdev_t vd, uint64_t asize, uint64_t *ashift)
	54	{
34dc7c2f BB	55	int lasterror = 0;
	56	int numerrors = 0;
	57
	58	if (vd->vdev_children == 0) {
	59	vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
	60	return (EINVAL);
	61	}
	62
45d1cae3 BB	63	vdev_open_children(vd);
	64
	65	for (int c = 0; c < vd->vdev_children; c++) {
34dc7c2f	66	vdev_t *cvd = vd->vdev_child[c];
34dc7c2f	67
45d1cae3 BB	68	if (cvd->vdev_open_error && !cvd->vdev_islog) {
45d1cae3 BB	69	lasterror = cvd->vdev_open_error;
34dc7c2f	70	numerrors++;
34dc7c2f BB	71	}
	72	}
	73
b128c09f BB	74	if (too_many_errors(vd, numerrors)) {
	75	vd->vdev_stat.vs_aux = VDEV_AUX_NO_REPLICAS;
	76	return (lasterror);
34dc7c2f BB	77	}
	78
	79	*asize = 0;
	80	*ashift = 0;
	81
	82	return (0);
	83	}
	84
	85	static void
	86	vdev_root_close(vdev_t *vd)
	87	{
45d1cae3	88	for (int c = 0; c < vd->vdev_children; c++)
34dc7c2f BB	89	vdev_close(vd->vdev_child[c]);
	90	}
	91
	92	static void
	93	vdev_root_state_change(vdev_t *vd, int faulted, int degraded)
	94	{
b128c09f BB	95	if (too_many_errors(vd, faulted)) {
	96	vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
	97	VDEV_AUX_NO_REPLICAS);
34dc7c2f BB	98	} else if (degraded) {
	99	vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, VDEV_AUX_NONE);
	100	} else {
	101	vdev_set_state(vd, B_FALSE, VDEV_STATE_HEALTHY, VDEV_AUX_NONE);
	102	}
	103	}
	104
	105	vdev_ops_t vdev_root_ops = {
	106	vdev_root_open,
	107	vdev_root_close,
34dc7c2f BB	108	vdev_default_asize,
	109	NULL, /* io_start - not applicable to the root */
	110	NULL, /* io_done - not applicable to the root */
	111	vdev_root_state_change,
428870ff BB	112	NULL,
428870ff BB	113	NULL,
34dc7c2f BB	114	VDEV_TYPE_ROOT, /* name of this vdev type */
	115	B_FALSE /* not a leaf vdev */
	116	};