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/*
22 * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
23 * Use is subject to license terms.
24 */
25
26/*
27 * Copyright (c) 2013 by Delphix. All rights reserved.
28 */
29
30#include <sys/zfs_context.h>
31#include <sys/spa.h>
32#include <sys/vdev_impl.h>
33#include <sys/zio.h>
34#include <sys/fs/zfs.h>
35
36/*
37 * Virtual device vector for the pool's root vdev.
38 */
39
40/*
41 * We should be able to tolerate one failure with absolutely no damage
42 * to our metadata.  Two failures will take out space maps, a bunch of
43 * indirect block trees, meta dnodes, dnodes, etc.  Probably not a happy
44 * place to live.  When we get smarter, we can liberalize this policy.
45 * e.g. If we haven't lost two consecutive top-level vdevs, then we are
46 * probably fine.  Adding bean counters during alloc/free can make this
47 * future guesswork more accurate.
48 */
49static int
50too_many_errors(vdev_t *vd, int numerrors)
51{
52	ASSERT3U(numerrors, <=, vd->vdev_children);
53	return (numerrors > 0);
54}
55
56static int
57vdev_root_open(vdev_t *vd, uint64_t *asize, uint64_t *max_asize,
58    uint64_t *logical_ashift, uint64_t *physical_ashift)
59{
60	int lasterror = 0;
61	int numerrors = 0;
62
63	if (vd->vdev_children == 0) {
64		vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
65		return (SET_ERROR(EINVAL));
66	}
67
68	vdev_open_children(vd);
69
70	for (int c = 0; c < vd->vdev_children; c++) {
71		vdev_t *cvd = vd->vdev_child[c];
72
73		if (cvd->vdev_open_error && !cvd->vdev_islog) {
74			lasterror = cvd->vdev_open_error;
75			numerrors++;
76		}
77	}
78
79	if (too_many_errors(vd, numerrors)) {
80		vd->vdev_stat.vs_aux = VDEV_AUX_NO_REPLICAS;
81		return (lasterror);
82	}
83
84	*asize = 0;
85	*max_asize = 0;
86	*logical_ashift = 0;
87	*physical_ashift = 0;
88
89	return (0);
90}
91
92static void
93vdev_root_close(vdev_t *vd)
94{
95	for (int c = 0; c < vd->vdev_children; c++)
96		vdev_close(vd->vdev_child[c]);
97}
98
99static void
100vdev_root_state_change(vdev_t *vd, int faulted, int degraded)
101{
102	if (too_many_errors(vd, faulted)) {
103		vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
104		    VDEV_AUX_NO_REPLICAS);
105	} else if (degraded) {
106		vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, VDEV_AUX_NONE);
107	} else {
108		vdev_set_state(vd, B_FALSE, VDEV_STATE_HEALTHY, VDEV_AUX_NONE);
109	}
110}
111
112vdev_ops_t vdev_root_ops = {
113	vdev_root_open,
114	vdev_root_close,
115	vdev_default_asize,
116	NULL,			/* io_start - not applicable to the root */
117	NULL,			/* io_done - not applicable to the root */
118	vdev_root_state_change,
119	NULL,
120	NULL,
121	VDEV_TYPE_ROOT,		/* name of this vdev type */
122	B_FALSE			/* not a leaf vdev */
123};
124