xref: /illumos-gate/usr/src/uts/common/fs/zfs/vdev_missing.c (revision a3874b8b1fe5103fc1f961609557c0587435fec0)
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, 2016 by Delphix. All rights reserved.
28  */
29 
30 /*
31  * The 'missing' vdev is a special vdev type used only during import.  It
32  * signifies a placeholder in the root vdev for some vdev that we know is
33  * missing.  We pass it down to the kernel to allow the rest of the
34  * configuration to parsed and an attempt made to open all available devices.
35  * Because its GUID is always 0, we know that the guid sum will mismatch and we
36  * won't be able to open the pool anyway.
37  */
38 
39 #include <sys/zfs_context.h>
40 #include <sys/spa.h>
41 #include <sys/vdev_impl.h>
42 #include <sys/fs/zfs.h>
43 #include <sys/zio.h>
44 
45 /* ARGSUSED */
46 static int
47 vdev_missing_open(vdev_t *vd, uint64_t *psize, uint64_t *max_psize,
48     uint64_t *ashift)
49 {
50 	/*
51 	 * Really this should just fail.  But then the root vdev will be in the
52 	 * faulted state with VDEV_AUX_NO_REPLICAS, when what we really want is
53 	 * VDEV_AUX_BAD_GUID_SUM.  So we pretend to succeed, knowing that we
54 	 * will fail the GUID sum check before ever trying to open the pool.
55 	 */
56 	*psize = 0;
57 	*max_psize = 0;
58 	*ashift = 0;
59 	return (0);
60 }
61 
62 /* ARGSUSED */
63 static void
64 vdev_missing_close(vdev_t *vd)
65 {
66 }
67 
68 /* ARGSUSED */
69 static void
70 vdev_missing_io_start(zio_t *zio)
71 {
72 	zio->io_error = SET_ERROR(ENOTSUP);
73 	zio_execute(zio);
74 }
75 
76 /* ARGSUSED */
77 static void
78 vdev_missing_io_done(zio_t *zio)
79 {
80 }
81 
82 vdev_ops_t vdev_missing_ops = {
83 	.vdev_op_open = vdev_missing_open,
84 	.vdev_op_close = vdev_missing_close,
85 	.vdev_op_asize = vdev_default_asize,
86 	.vdev_op_io_start = vdev_missing_io_start,
87 	.vdev_op_io_done = vdev_missing_io_done,
88 	.vdev_op_state_change = NULL,
89 	.vdev_op_need_resilver = NULL,
90 	.vdev_op_hold = NULL,
91 	.vdev_op_rele = NULL,
92 	.vdev_op_remap = NULL,
93 	.vdev_op_xlate = NULL,
94 	.vdev_op_type = VDEV_TYPE_MISSING,	/* name of this vdev type */
95 	.vdev_op_leaf = B_TRUE			/* leaf vdev */
96 };
97 
98 vdev_ops_t vdev_hole_ops = {
99 	.vdev_op_open = vdev_missing_open,
100 	.vdev_op_close = vdev_missing_close,
101 	.vdev_op_asize = vdev_default_asize,
102 	.vdev_op_io_start = vdev_missing_io_start,
103 	.vdev_op_io_done = vdev_missing_io_done,
104 	.vdev_op_state_change = NULL,
105 	.vdev_op_need_resilver = NULL,
106 	.vdev_op_hold = NULL,
107 	.vdev_op_rele = NULL,
108 	.vdev_op_remap = NULL,
109 	.vdev_op_xlate = NULL,
110 	.vdev_op_type = VDEV_TYPE_HOLE,		/* name of this vdev type */
111 	.vdev_op_leaf = B_TRUE			/* leaf vdev */
112 };
113