1 /*- 2 * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 #include <sys/param.h> 30 #include <sys/bio.h> 31 #include <sys/kernel.h> 32 #include <sys/limits.h> 33 #include <sys/malloc.h> 34 #include <sys/queue.h> 35 #include <sys/sysctl.h> 36 #include <sys/systm.h> 37 38 #include <geom/geom.h> 39 40 41 #define G_ZERO_CLASS_NAME "ZERO" 42 43 SYSCTL_DECL(_kern_geom); 44 SYSCTL_NODE(_kern_geom, OID_AUTO, zero, CTLFLAG_RW, 0, "GEOM_ZERO stuff"); 45 static u_int g_zero_clear = 1; 46 SYSCTL_UINT(_kern_geom_zero, OID_AUTO, clear, CTLFLAG_RW, &g_zero_clear, 0, 47 "Zero-fill bio_data."); 48 49 static void 50 g_zero_start(struct bio *bp) 51 { 52 int error = ENXIO; 53 54 switch (bp->bio_cmd) { 55 case BIO_READ: 56 if (g_zero_clear) 57 bzero(bp->bio_data, bp->bio_length); 58 /* FALLTHROUGH */ 59 case BIO_DELETE: 60 case BIO_WRITE: 61 bp->bio_completed = bp->bio_length; 62 error = 0; 63 break; 64 case BIO_GETATTR: 65 default: 66 error = EOPNOTSUPP; 67 break; 68 } 69 g_io_deliver(bp, error); 70 } 71 72 static void 73 g_zero_init(struct g_class *mp) 74 { 75 struct g_geom *gp; 76 struct g_provider *pp; 77 78 g_topology_assert(); 79 gp = g_new_geomf(mp, "gzero"); 80 gp->start = g_zero_start; 81 gp->access = g_std_access; 82 pp = g_new_providerf(gp, "%s", gp->name); 83 pp->mediasize = 1152921504606846976LLU; 84 pp->sectorsize = 512; 85 g_error_provider(pp, 0); 86 } 87 88 static int 89 g_zero_destroy_geom(struct gctl_req *req __unused, struct g_class *mp __unused, 90 struct g_geom *gp) 91 { 92 struct g_provider *pp; 93 94 g_topology_assert(); 95 if (gp == NULL) 96 return (0); 97 pp = LIST_FIRST(&gp->provider); 98 if (pp == NULL) 99 return (0); 100 if (pp->acr > 0 || pp->acw > 0 || pp->ace > 0) 101 return (EBUSY); 102 g_wither_geom(gp, ENXIO); 103 return (EBUSY); 104 } 105 106 static struct g_class g_zero_class = { 107 .name = G_ZERO_CLASS_NAME, 108 .version = G_VERSION, 109 .init = g_zero_init, 110 .destroy_geom = g_zero_destroy_geom 111 }; 112 113 DECLARE_GEOM_CLASS(g_zero_class, g_zero); 114