xref: /freebsd/sys/geom/zero/g_zero.c (revision 5a279fc5fcbac39aa590b663618f59b90c1701a6)
1565bc101SPawel Jakub Dawidek /*-
2565bc101SPawel Jakub Dawidek  * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
3565bc101SPawel Jakub Dawidek  * All rights reserved.
4565bc101SPawel Jakub Dawidek  *
5565bc101SPawel Jakub Dawidek  * Redistribution and use in source and binary forms, with or without
6565bc101SPawel Jakub Dawidek  * modification, are permitted provided that the following conditions
7565bc101SPawel Jakub Dawidek  * are met:
8565bc101SPawel Jakub Dawidek  * 1. Redistributions of source code must retain the above copyright
9565bc101SPawel Jakub Dawidek  *    notice, this list of conditions and the following disclaimer.
10565bc101SPawel Jakub Dawidek  * 2. Redistributions in binary form must reproduce the above copyright
11565bc101SPawel Jakub Dawidek  *    notice, this list of conditions and the following disclaimer in the
12565bc101SPawel Jakub Dawidek  *    documentation and/or other materials provided with the distribution.
13565bc101SPawel Jakub Dawidek  *
14565bc101SPawel Jakub Dawidek  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
15565bc101SPawel Jakub Dawidek  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16565bc101SPawel Jakub Dawidek  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17565bc101SPawel Jakub Dawidek  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
18565bc101SPawel Jakub Dawidek  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19565bc101SPawel Jakub Dawidek  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20565bc101SPawel Jakub Dawidek  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21565bc101SPawel Jakub Dawidek  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22565bc101SPawel Jakub Dawidek  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23565bc101SPawel Jakub Dawidek  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24565bc101SPawel Jakub Dawidek  * SUCH DAMAGE.
25565bc101SPawel Jakub Dawidek  */
26565bc101SPawel Jakub Dawidek 
27a1c10dcbSPawel Jakub Dawidek #include <sys/cdefs.h>
28a1c10dcbSPawel Jakub Dawidek __FBSDID("$FreeBSD$");
29a1c10dcbSPawel Jakub Dawidek 
30565bc101SPawel Jakub Dawidek #include <sys/param.h>
31565bc101SPawel Jakub Dawidek #include <sys/bio.h>
32565bc101SPawel Jakub Dawidek #include <sys/kernel.h>
33565bc101SPawel Jakub Dawidek #include <sys/limits.h>
34565bc101SPawel Jakub Dawidek #include <sys/malloc.h>
35565bc101SPawel Jakub Dawidek #include <sys/queue.h>
36565bc101SPawel Jakub Dawidek #include <sys/sysctl.h>
37565bc101SPawel Jakub Dawidek #include <sys/systm.h>
38565bc101SPawel Jakub Dawidek 
39565bc101SPawel Jakub Dawidek #include <geom/geom.h>
40565bc101SPawel Jakub Dawidek 
41565bc101SPawel Jakub Dawidek 
42565bc101SPawel Jakub Dawidek #define	G_ZERO_CLASS_NAME	"ZERO"
43565bc101SPawel Jakub Dawidek 
44565bc101SPawel Jakub Dawidek SYSCTL_DECL(_kern_geom);
45565bc101SPawel Jakub Dawidek SYSCTL_NODE(_kern_geom, OID_AUTO, zero, CTLFLAG_RW, 0, "GEOM_ZERO stuff");
4624e1fdcdSPawel Jakub Dawidek static int g_zero_clear = 1;
4724e1fdcdSPawel Jakub Dawidek SYSCTL_INT(_kern_geom_zero, OID_AUTO, clear, CTLFLAG_RW, &g_zero_clear, 0,
4824e1fdcdSPawel Jakub Dawidek     "Clear read data buffer");
4924e1fdcdSPawel Jakub Dawidek static int g_zero_byte = 0;
5024e1fdcdSPawel Jakub Dawidek SYSCTL_INT(_kern_geom_zero, OID_AUTO, byte, CTLFLAG_RW, &g_zero_byte, 0,
5124e1fdcdSPawel Jakub Dawidek     "Byte (octet) value to clear the buffers with");
52565bc101SPawel Jakub Dawidek 
53565bc101SPawel Jakub Dawidek static void
54565bc101SPawel Jakub Dawidek g_zero_start(struct bio *bp)
55565bc101SPawel Jakub Dawidek {
56565bc101SPawel Jakub Dawidek 	int error = ENXIO;
57565bc101SPawel Jakub Dawidek 
58565bc101SPawel Jakub Dawidek 	switch (bp->bio_cmd) {
59565bc101SPawel Jakub Dawidek 	case BIO_READ:
60565bc101SPawel Jakub Dawidek 		if (g_zero_clear)
6124e1fdcdSPawel Jakub Dawidek 			memset(bp->bio_data, g_zero_byte, bp->bio_length);
62565bc101SPawel Jakub Dawidek 		/* FALLTHROUGH */
63565bc101SPawel Jakub Dawidek 	case BIO_DELETE:
64565bc101SPawel Jakub Dawidek 	case BIO_WRITE:
65565bc101SPawel Jakub Dawidek 		bp->bio_completed = bp->bio_length;
66565bc101SPawel Jakub Dawidek 		error = 0;
67565bc101SPawel Jakub Dawidek 		break;
68565bc101SPawel Jakub Dawidek 	case BIO_GETATTR:
69565bc101SPawel Jakub Dawidek 	default:
70565bc101SPawel Jakub Dawidek 		error = EOPNOTSUPP;
71565bc101SPawel Jakub Dawidek 		break;
72565bc101SPawel Jakub Dawidek 	}
73565bc101SPawel Jakub Dawidek 	g_io_deliver(bp, error);
74565bc101SPawel Jakub Dawidek }
75565bc101SPawel Jakub Dawidek 
76565bc101SPawel Jakub Dawidek static void
77565bc101SPawel Jakub Dawidek g_zero_init(struct g_class *mp)
78565bc101SPawel Jakub Dawidek {
79565bc101SPawel Jakub Dawidek 	struct g_geom *gp;
80565bc101SPawel Jakub Dawidek 	struct g_provider *pp;
81565bc101SPawel Jakub Dawidek 
82565bc101SPawel Jakub Dawidek 	g_topology_assert();
83565bc101SPawel Jakub Dawidek 	gp = g_new_geomf(mp, "gzero");
84565bc101SPawel Jakub Dawidek 	gp->start = g_zero_start;
85565bc101SPawel Jakub Dawidek 	gp->access = g_std_access;
86565bc101SPawel Jakub Dawidek 	pp = g_new_providerf(gp, "%s", gp->name);
87565bc101SPawel Jakub Dawidek 	pp->mediasize = 1152921504606846976LLU;
88565bc101SPawel Jakub Dawidek 	pp->sectorsize = 512;
89565bc101SPawel Jakub Dawidek 	g_error_provider(pp, 0);
90565bc101SPawel Jakub Dawidek }
91565bc101SPawel Jakub Dawidek 
92565bc101SPawel Jakub Dawidek static int
93565bc101SPawel Jakub Dawidek g_zero_destroy_geom(struct gctl_req *req __unused, struct g_class *mp __unused,
94565bc101SPawel Jakub Dawidek     struct g_geom *gp)
95565bc101SPawel Jakub Dawidek {
96565bc101SPawel Jakub Dawidek 	struct g_provider *pp;
97565bc101SPawel Jakub Dawidek 
98565bc101SPawel Jakub Dawidek 	g_topology_assert();
99565bc101SPawel Jakub Dawidek 	if (gp == NULL)
100565bc101SPawel Jakub Dawidek 		return (0);
101565bc101SPawel Jakub Dawidek 	pp = LIST_FIRST(&gp->provider);
102565bc101SPawel Jakub Dawidek 	if (pp == NULL)
103565bc101SPawel Jakub Dawidek 		return (0);
104565bc101SPawel Jakub Dawidek 	if (pp->acr > 0 || pp->acw > 0 || pp->ace > 0)
105565bc101SPawel Jakub Dawidek 		return (EBUSY);
106565bc101SPawel Jakub Dawidek 	g_wither_geom(gp, ENXIO);
107*5a279fc5SJaakko Heinonen 	return (0);
108565bc101SPawel Jakub Dawidek }
109565bc101SPawel Jakub Dawidek 
110565bc101SPawel Jakub Dawidek static struct g_class g_zero_class = {
111565bc101SPawel Jakub Dawidek 	.name = G_ZERO_CLASS_NAME,
112565bc101SPawel Jakub Dawidek 	.version = G_VERSION,
113565bc101SPawel Jakub Dawidek 	.init = g_zero_init,
114565bc101SPawel Jakub Dawidek 	.destroy_geom = g_zero_destroy_geom
115565bc101SPawel Jakub Dawidek };
116565bc101SPawel Jakub Dawidek 
117565bc101SPawel Jakub Dawidek DECLARE_GEOM_CLASS(g_zero_class, g_zero);
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