xref: /illumos-gate/usr/src/uts/common/fs/zfs/vdev_root.c (revision 6f7938128a2c5e23f4b970ea101137eadd1470a1)
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) 2012, 2014 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 static uint64_t
41 vdev_root_core_tvds(vdev_t *vd)
42 {
43 	uint64_t tvds = 0;
44 
45 	for (uint64_t c = 0; c < vd->vdev_children; c++) {
46 		vdev_t *cvd = vd->vdev_child[c];
47 
48 		if (!cvd->vdev_ishole && !cvd->vdev_islog &&
49 		    cvd->vdev_ops != &vdev_indirect_ops) {
50 			tvds++;
51 		}
52 	}
53 
54 	return (tvds);
55 }
56 
57 /*
58  * We should be able to tolerate one failure with absolutely no damage
59  * to our metadata.  Two failures will take out space maps, a bunch of
60  * indirect block trees, meta dnodes, dnodes, etc.  Probably not a happy
61  * place to live.  When we get smarter, we can liberalize this policy.
62  * e.g. If we haven't lost two consecutive top-level vdevs, then we are
63  * probably fine.  Adding bean counters during alloc/free can make this
64  * future guesswork more accurate.
65  */
66 static boolean_t
67 too_many_errors(vdev_t *vd, uint64_t numerrors)
68 {
69 	uint64_t tvds;
70 
71 	if (numerrors == 0)
72 		return (B_FALSE);
73 
74 	tvds = vdev_root_core_tvds(vd);
75 	ASSERT3U(numerrors, <=, tvds);
76 
77 	if (numerrors == tvds)
78 		return (B_TRUE);
79 
80 	return (numerrors > spa_missing_tvds_allowed(vd->vdev_spa));
81 }
82 
83 static int
84 vdev_root_open(vdev_t *vd, uint64_t *asize, uint64_t *max_asize,
85     uint64_t *ashift)
86 {
87 	spa_t *spa = vd->vdev_spa;
88 	int lasterror = 0;
89 	int numerrors = 0;
90 
91 	if (vd->vdev_children == 0) {
92 		vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
93 		return (SET_ERROR(EINVAL));
94 	}
95 
96 	vdev_open_children(vd);
97 
98 	for (int c = 0; c < vd->vdev_children; c++) {
99 		vdev_t *cvd = vd->vdev_child[c];
100 
101 		if (cvd->vdev_open_error && !cvd->vdev_islog) {
102 			lasterror = cvd->vdev_open_error;
103 			numerrors++;
104 		}
105 	}
106 
107 	if (spa_load_state(spa) != SPA_LOAD_NONE)
108 		spa_set_missing_tvds(spa, numerrors);
109 
110 	if (too_many_errors(vd, numerrors)) {
111 		vd->vdev_stat.vs_aux = VDEV_AUX_NO_REPLICAS;
112 		return (lasterror);
113 	}
114 
115 	*asize = 0;
116 	*max_asize = 0;
117 	*ashift = 0;
118 
119 	return (0);
120 }
121 
122 static void
123 vdev_root_close(vdev_t *vd)
124 {
125 	for (int c = 0; c < vd->vdev_children; c++)
126 		vdev_close(vd->vdev_child[c]);
127 }
128 
129 static void
130 vdev_root_state_change(vdev_t *vd, int faulted, int degraded)
131 {
132 	if (too_many_errors(vd, faulted)) {
133 		vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
134 		    VDEV_AUX_NO_REPLICAS);
135 	} else if (degraded || faulted) {
136 		vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, VDEV_AUX_NONE);
137 	} else {
138 		vdev_set_state(vd, B_FALSE, VDEV_STATE_HEALTHY, VDEV_AUX_NONE);
139 	}
140 }
141 
142 vdev_ops_t vdev_root_ops = {
143 	vdev_root_open,
144 	vdev_root_close,
145 	vdev_default_asize,
146 	NULL,			/* io_start - not applicable to the root */
147 	NULL,			/* io_done - not applicable to the root */
148 	vdev_root_state_change,
149 	NULL,
150 	NULL,
151 	NULL,
152 	VDEV_TYPE_ROOT,		/* name of this vdev type */
153 	B_FALSE			/* not a leaf vdev */
154 };
155