xref: /titanic_41/usr/src/uts/common/fs/zfs/vdev_root.c (revision be6fd75a69ae679453d9cda5bff3326111e6d1ca)
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  */
49 static int
too_many_errors(vdev_t * vd,int numerrors)50 too_many_errors(vdev_t *vd, int numerrors)
51 {
52 	ASSERT3U(numerrors, <=, vd->vdev_children);
53 	return (numerrors > 0);
54 }
55 
56 static int
vdev_root_open(vdev_t * vd,uint64_t * asize,uint64_t * max_asize,uint64_t * ashift)57 vdev_root_open(vdev_t *vd, uint64_t *asize, uint64_t *max_asize,
58     uint64_t *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 	*ashift = 0;
87 
88 	return (0);
89 }
90 
91 static void
vdev_root_close(vdev_t * vd)92 vdev_root_close(vdev_t *vd)
93 {
94 	for (int c = 0; c < vd->vdev_children; c++)
95 		vdev_close(vd->vdev_child[c]);
96 }
97 
98 static void
vdev_root_state_change(vdev_t * vd,int faulted,int degraded)99 vdev_root_state_change(vdev_t *vd, int faulted, int degraded)
100 {
101 	if (too_many_errors(vd, faulted)) {
102 		vdev_set_state(vd, B_FALSE, VDEV_STATE_CANT_OPEN,
103 		    VDEV_AUX_NO_REPLICAS);
104 	} else if (degraded) {
105 		vdev_set_state(vd, B_FALSE, VDEV_STATE_DEGRADED, VDEV_AUX_NONE);
106 	} else {
107 		vdev_set_state(vd, B_FALSE, VDEV_STATE_HEALTHY, VDEV_AUX_NONE);
108 	}
109 }
110 
111 vdev_ops_t vdev_root_ops = {
112 	vdev_root_open,
113 	vdev_root_close,
114 	vdev_default_asize,
115 	NULL,			/* io_start - not applicable to the root */
116 	NULL,			/* io_done - not applicable to the root */
117 	vdev_root_state_change,
118 	NULL,
119 	NULL,
120 	VDEV_TYPE_ROOT,		/* name of this vdev type */
121 	B_FALSE			/* not a leaf vdev */
122 };
123