disksubr.c revision 1.27
1/* $NetBSD: disksubr.c,v 1.27 2008/01/02 11:48:25 ad Exp $ */ 2 3/* 4 * Copyright (c) 1982, 1986, 1988, 1993 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)ufs_disksubr.c 8.5 (Berkeley) 1/21/94 37 */ 38 39#include <sys/cdefs.h> 40__KERNEL_RCSID(0, "$NetBSD: disksubr.c,v 1.27 2008/01/02 11:48:25 ad Exp $"); 41 42#include <sys/param.h> 43#include <sys/systm.h> 44#include <sys/buf.h> 45#include <sys/disk.h> 46#include <sys/disklabel.h> 47 48/* 49 * Attempt to read a disk label from a device using the indicated strategy 50 * routine. The label must be partly set up before this: secpercyl and 51 * anything required in the strategy routine (e.g., sector size) must be 52 * filled in before calling us. Returns null on success and an error 53 * string on failure. 54 */ 55const char * 56readdisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp, 57 struct cpu_disklabel *osdep) 58{ 59 struct buf *bp; 60 struct disklabel *dlp; 61 const char *msg = NULL; 62 int i; 63 64 if (lp->d_secsize == 0) 65 lp->d_secsize = DEV_BSIZE; 66 if (lp->d_secperunit == 0) 67 lp->d_secperunit = 0x1fffffff; 68 if (lp->d_npartitions < RAW_PART + 1) 69 lp->d_npartitions = RAW_PART + 1; 70 for (i = 0; i < RAW_PART; i++) { 71 lp->d_partitions[i].p_size = 0; 72 lp->d_partitions[i].p_offset = 0; 73 } 74 if (lp->d_partitions[RAW_PART].p_size == 0) 75 lp->d_partitions[RAW_PART].p_size = lp->d_secperunit; 76 lp->d_partitions[RAW_PART].p_offset = 0; 77 78 lp->d_partitions[0].p_size = lp->d_partitions[RAW_PART].p_size; 79 lp->d_partitions[0].p_fstype = FS_BSDFFS; 80 81 bp = geteblk((int)lp->d_secsize); 82 bp->b_dev = dev; 83 bp->b_blkno = LABELSECTOR; 84 bp->b_bcount = lp->d_secsize; 85 bp->b_flags |= B_READ; 86 bp->b_cylinder = LABELSECTOR / lp->d_secpercyl; 87 (*strat)(bp); 88 if (biowait(bp)) 89 msg = "I/O error"; 90 else for (dlp = (struct disklabel *)bp->b_data; 91 dlp <= (struct disklabel *)((char *)bp->b_data + 92 DEV_BSIZE - sizeof(*dlp)); 93 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { 94 if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) { 95 if (msg == NULL) 96 msg = "no disk label"; 97 } else if (dlp->d_npartitions > MAXPARTITIONS || 98 dkcksum(dlp) != 0) 99 msg = "disk label corrupted"; 100 else { 101 *lp = *dlp; 102 msg = NULL; 103 break; 104 } 105 } 106 brelse(bp, 0); 107 return msg; 108} 109 110/* 111 * Check new disk label for sensibility before setting it. 112 */ 113int 114setdisklabel(struct disklabel *olp, struct disklabel *nlp, u_long openmask, 115 struct cpu_disklabel *osdep) 116{ 117 int i; 118 struct partition *opp, *npp; 119 120 if (nlp->d_magic != DISKMAGIC || nlp->d_magic2 != DISKMAGIC || 121 dkcksum(nlp) != 0) 122 return EINVAL; 123 while ((i = ffs(openmask)) != 0) { 124 i--; 125 openmask &= ~(1 << i); 126 if (nlp->d_npartitions <= i) 127 return EBUSY; 128 opp = &olp->d_partitions[i]; 129 npp = &nlp->d_partitions[i]; 130 if (npp->p_offset != opp->p_offset || npp->p_size < opp->p_size) 131 return EBUSY; 132 /* 133 * Copy internally-set partition information 134 * if new label doesn't include it. XXX 135 */ 136 if (npp->p_fstype == FS_UNUSED && opp->p_fstype != FS_UNUSED) { 137 npp->p_fstype = opp->p_fstype; 138 npp->p_fsize = opp->p_fsize; 139 npp->p_frag = opp->p_frag; 140 npp->p_cpg = opp->p_cpg; 141 } 142 } 143 nlp->d_checksum = 0; 144 nlp->d_checksum = dkcksum(nlp); 145 *olp = *nlp; 146 return 0; 147} 148 149/* 150 * Write disk label back to device after modification. 151 */ 152int 153writedisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp, 154 struct cpu_disklabel *osdep) 155{ 156 struct buf *bp; 157 struct disklabel *dlp; 158 int labelpart; 159 int error = 0; 160 161 labelpart = DISKPART(dev); 162 if (lp->d_partitions[labelpart].p_offset != 0) { 163 if (lp->d_partitions[0].p_offset != 0) 164 return EXDEV; /* not quite right */ 165 labelpart = 0; 166 } 167 bp = geteblk((int)lp->d_secsize); 168 bp->b_dev = MAKEDISKDEV(major(dev), DISKUNIT(dev), labelpart); 169 bp->b_blkno = LABELSECTOR; 170 bp->b_bcount = lp->d_secsize; 171 bp->b_flags |= B_READ; 172 (*strat)(bp); 173 if ((error = biowait(bp)) != 0) 174 goto done; 175 for (dlp = (struct disklabel *)bp->b_data; 176 dlp <= (struct disklabel *) 177 ((char *)bp->b_data + lp->d_secsize - sizeof(*dlp)); 178 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { 179 if (dlp->d_magic == DISKMAGIC && dlp->d_magic2 == DISKMAGIC && 180 dkcksum(dlp) == 0) { 181 *dlp = *lp; 182 bp->b_oflags &= ~(BO_DONE); 183 bp->b_flags &= ~(B_READ); 184 bp->b_flags |= B_WRITE; 185 (*strat)(bp); 186 error = biowait(bp); 187 goto done; 188 } 189 } 190 error = ESRCH; 191 done: 192 brelse(bp, 0); 193 return error; 194} 195