xref: /illumos-gate/usr/src/uts/common/fs/zfs/vdev_root.c (revision cd11837edb943ce20ca539d505e60b469f89bf20)
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 2008 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
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);
49 	return (numerrors > 0);
50 }
51 
52 static int
53 vdev_root_open(vdev_t *vd, uint64_t *asize, uint64_t *ashift)
54 {
55 	int c;
56 	int lasterror = 0;
57 	int numerrors = 0;
58 
59 	if (vd->vdev_children == 0) {
60 		vd->vdev_stat.vs_aux = VDEV_AUX_BAD_LABEL;
61 		return (EINVAL);
62 	}
63 
64 	for (c = 0; c < vd->vdev_children; c++) {
65 		vdev_t *cvd = vd->vdev_child[c];
66 		int error;
67 
68 		if ((error = vdev_open(cvd)) != 0 &&
69 		    !cvd->vdev_islog) {
70 			lasterror = error;
71 			numerrors++;
72 			continue;
73 		}
74 	}
75 
76 	if (too_many_errors(vd, numerrors)) {
77 		vd->vdev_stat.vs_aux = VDEV_AUX_NO_REPLICAS;
78 		return (lasterror);
79 	}
80 
81 	*asize = 0;
82 	*ashift = 0;
83 
84 	return (0);
85 }
86 
87 static void
88 vdev_root_close(vdev_t *vd)
89 {
90 	int c;
91 
92 	for (c = 0; c < vd->vdev_children; c++)
93 		vdev_close(vd->vdev_child[c]);
94 }
95 
96 static void
97 vdev_root_state_change(vdev_t *vd, int faulted, int degraded)
98 {
99 	if (too_many_errors(vd, faulted)) {
100 		vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
101 		    VDEV_AUX_NO_REPLICAS);
102 	} else if (degraded) {
103 		vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, VDEV_AUX_NONE);
104 	} else {
105 		vdev_set_state(vd, B_FALSE, VDEV_STATE_HEALTHY, VDEV_AUX_NONE);
106 	}
107 }
108 
109 vdev_ops_t vdev_root_ops = {
110 	vdev_root_open,
111 	vdev_root_close,
112 	vdev_default_asize,
113 	NULL,			/* io_start - not applicable to the root */
114 	NULL,			/* io_done - not applicable to the root */
115 	vdev_root_state_change,
116 	VDEV_TYPE_ROOT,		/* name of this vdev type */
117 	B_FALSE			/* not a leaf vdev */
118 };
119