xref: /titanic_41/usr/src/uts/common/fs/zfs/vdev_missing.c (revision 0bb073995ac5a95bd35f2dd790df1ea3d8c2d507)
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 2007 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
27 
28 /*
29  * The 'missing' vdev is a special vdev type used only during import.  It
30  * signifies a placeholder in the root vdev for some vdev that we know is
31  * missing.  We pass it down to the kernel to allow the rest of the
32  * configuration to parsed and an attempt made to open all available devices.
33  * Because its GUID is always 0, we know that the guid sum will mismatch and we
34  * won't be able to open the pool anyway.
35  */
36 
37 #include <sys/zfs_context.h>
38 #include <sys/spa.h>
39 #include <sys/vdev_impl.h>
40 #include <sys/fs/zfs.h>
41 #include <sys/zio.h>
42 
43 /* ARGSUSED */
44 static int
45 vdev_missing_open(vdev_t *vd, uint64_t *psize, uint64_t *ashift)
46 {
47 	/*
48 	 * Really this should just fail.  But then the root vdev will be in the
49 	 * faulted state with VDEV_AUX_NO_REPLICAS, when what we really want is
50 	 * VDEV_AUX_BAD_GUID_SUM.  So we pretend to succeed, knowing that we
51 	 * will fail the GUID sum check before ever trying to open the pool.
52 	 */
53 	*psize = SPA_MINDEVSIZE;
54 	*ashift = SPA_MINBLOCKSHIFT;
55 	return (0);
56 }
57 
58 /* ARGSUSED */
59 static void
60 vdev_missing_close(vdev_t *vd)
61 {
62 }
63 
64 /* ARGSUSED */
65 static int
66 vdev_missing_io_start(zio_t *zio)
67 {
68 	zio->io_error = ENOTSUP;
69 	return (ZIO_PIPELINE_CONTINUE);
70 }
71 
72 /* ARGSUSED */
73 static int
74 vdev_missing_io_done(zio_t *zio)
75 {
76 	return (ZIO_PIPELINE_CONTINUE);
77 }
78 
79 /* ARGSUSED */
80 static int
81 vdev_missing_probe(vdev_t *vd)
82 {
83 	return (0);
84 }
85 
86 vdev_ops_t vdev_missing_ops = {
87 	vdev_missing_open,
88 	vdev_missing_close,
89 	vdev_missing_probe,
90 	vdev_default_asize,
91 	vdev_missing_io_start,
92 	vdev_missing_io_done,
93 	NULL,
94 	VDEV_TYPE_MISSING,	/* name of this vdev type */
95 	B_TRUE			/* leaf vdev */
96 };
97