xref: /onnv-gate/usr/src/uts/common/fs/zfs/vdev_missing.c (revision 5329:33cb98223b2d)
1789Sahrens /*
2789Sahrens  * CDDL HEADER START
3789Sahrens  *
4789Sahrens  * The contents of this file are subject to the terms of the
5*5329Sgw25295  * Common Development and Distribution License (the "License").
6*5329Sgw25295  * You may not use this file except in compliance with the License.
7789Sahrens  *
8789Sahrens  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9789Sahrens  * or http://www.opensolaris.org/os/licensing.
10789Sahrens  * See the License for the specific language governing permissions
11789Sahrens  * and limitations under the License.
12789Sahrens  *
13789Sahrens  * When distributing Covered Code, include this CDDL HEADER in each
14789Sahrens  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15789Sahrens  * If applicable, add the following below this CDDL HEADER, with the
16789Sahrens  * fields enclosed by brackets "[]" replaced with your own identifying
17789Sahrens  * information: Portions Copyright [yyyy] [name of copyright owner]
18789Sahrens  *
19789Sahrens  * CDDL HEADER END
20789Sahrens  */
21789Sahrens /*
22*5329Sgw25295  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
23789Sahrens  * Use is subject to license terms.
24789Sahrens  */
25789Sahrens 
26789Sahrens #pragma ident	"%Z%%M%	%I%	%E% SMI"
27789Sahrens 
28789Sahrens /*
29789Sahrens  * The 'missing' vdev is a special vdev type used only during import.  It
30789Sahrens  * signifies a placeholder in the root vdev for some vdev that we know is
31789Sahrens  * missing.  We pass it down to the kernel to allow the rest of the
32789Sahrens  * configuration to parsed and an attempt made to open all available devices.
33789Sahrens  * Because its GUID is always 0, we know that the guid sum will mismatch and we
34789Sahrens  * won't be able to open the pool anyway.
35789Sahrens  */
36789Sahrens 
37789Sahrens #include <sys/zfs_context.h>
38789Sahrens #include <sys/spa.h>
39789Sahrens #include <sys/vdev_impl.h>
40789Sahrens #include <sys/fs/zfs.h>
41789Sahrens #include <sys/zio.h>
42789Sahrens 
43789Sahrens /* ARGSUSED */
44789Sahrens static int
45789Sahrens vdev_missing_open(vdev_t *vd, uint64_t *psize, uint64_t *ashift)
46789Sahrens {
47789Sahrens 	/*
48789Sahrens 	 * Really this should just fail.  But then the root vdev will be in the
49789Sahrens 	 * faulted state with VDEV_AUX_NO_REPLICAS, when what we really want is
50789Sahrens 	 * VDEV_AUX_BAD_GUID_SUM.  So we pretend to succeed, knowing that we
51789Sahrens 	 * will fail the GUID sum check before ever trying to open the pool.
52789Sahrens 	 */
53789Sahrens 	*psize = SPA_MINDEVSIZE;
54789Sahrens 	*ashift = SPA_MINBLOCKSHIFT;
55789Sahrens 	return (0);
56789Sahrens }
57789Sahrens 
58789Sahrens /* ARGSUSED */
59789Sahrens static void
60789Sahrens vdev_missing_close(vdev_t *vd)
61789Sahrens {
62789Sahrens }
63789Sahrens 
64789Sahrens /* ARGSUSED */
65789Sahrens static void
66789Sahrens vdev_missing_io_start(zio_t *zio)
67789Sahrens {
68789Sahrens 	zio->io_error = ENOTSUP;
69789Sahrens 	zio_next_stage_async(zio);
70789Sahrens }
71789Sahrens 
72789Sahrens /* ARGSUSED */
73789Sahrens static void
74789Sahrens vdev_missing_io_done(zio_t *zio)
75789Sahrens {
76789Sahrens 	zio_next_stage(zio);
77789Sahrens }
78789Sahrens 
79*5329Sgw25295 /* ARGSUSED */
80*5329Sgw25295 static int
81*5329Sgw25295 vdev_missing_probe(vdev_t *vd)
82*5329Sgw25295 {
83*5329Sgw25295 	return (0);
84*5329Sgw25295 }
85*5329Sgw25295 
86789Sahrens vdev_ops_t vdev_missing_ops = {
87789Sahrens 	vdev_missing_open,
88789Sahrens 	vdev_missing_close,
89*5329Sgw25295 	vdev_missing_probe,
90789Sahrens 	vdev_default_asize,
91789Sahrens 	vdev_missing_io_start,
92789Sahrens 	vdev_missing_io_done,
93789Sahrens 	NULL,
94789Sahrens 	VDEV_TYPE_MISSING,	/* name of this vdev type */
95789Sahrens 	B_TRUE			/* leaf vdev */
96789Sahrens };
97