disksubr.c revision 1.2
1/* 2 * Copyright (c) 1982, 1986, 1988 Regents of the University of California. 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 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * from: @(#)ufs_disksubr.c 7.16 (Berkeley) 5/4/91 34 * $Id: disksubr.c,v 1.2 1994/05/27 09:03:09 glass Exp $ 35 */ 36 37#include "param.h" 38#include "systm.h" 39#include "buf.h" 40#include "disklabel.h" 41#include "syslog.h" 42 43#define b_cylin b_resid 44 45/* 46 * Attempt to read a disk label from a device 47 * using the indicated stategy routine. 48 * The label must be partly set up before this: 49 * secpercyl and anything required in the strategy routine 50 * (e.g., sector size) must be filled in before calling us. 51 * Returns null on success and an error string on failure. 52 */ 53char * 54readdisklabel(dev, strat, lp, osdep) 55 dev_t dev; 56 void (*strat)(); 57 register struct disklabel *lp; 58 struct cpu_disklabel *osdep; 59{ 60 register struct buf *bp; 61 struct disklabel *dlp; 62 char *msg = NULL; 63 64 if (lp->d_secperunit == 0) 65 lp->d_secperunit = 0x1fffffff; 66 lp->d_npartitions = 1; 67 if (lp->d_partitions[0].p_size == 0) 68 lp->d_partitions[0].p_size = 0x1fffffff; 69 lp->d_partitions[0].p_offset = 0; 70 71 bp = geteblk((int)lp->d_secsize); 72 bp->b_dev = dev; 73 bp->b_blkno = LABELSECTOR; 74 bp->b_bcount = lp->d_secsize; 75 bp->b_flags = B_BUSY | B_READ; 76 bp->b_cylin = LABELSECTOR / lp->d_secpercyl; 77 (*strat)(bp); 78 if (biowait(bp)) { 79 msg = "I/O error"; 80 } else for (dlp = (struct disklabel *)bp->b_un.b_addr; 81 dlp <= (struct disklabel *)(bp->b_un.b_addr+DEV_BSIZE-sizeof(*dlp)); 82 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { 83 if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) { 84 if (msg == NULL) 85 msg = "no disk label"; 86 } else if (dlp->d_npartitions > MAXPARTITIONS || 87 dkcksum(dlp) != 0) 88 msg = "disk label corrupted"; 89 else { 90 *lp = *dlp; 91 msg = NULL; 92 break; 93 } 94 } 95 bp->b_flags = B_INVAL | B_AGE; 96 brelse(bp); 97 return (msg); 98} 99 100/* 101 * Check new disk label for sensibility 102 * before setting it. 103 */ 104setdisklabel(olp, nlp, openmask, osdep) 105 register struct disklabel *olp, *nlp; 106 u_long openmask; 107 struct cpu_disklabel *osdep; 108{ 109 register i; 110 register struct partition *opp, *npp; 111 112 if (nlp->d_magic != DISKMAGIC || nlp->d_magic2 != DISKMAGIC || 113 dkcksum(nlp) != 0) 114 return (EINVAL); 115 while ((i = ffs((long)openmask)) != 0) { 116 i--; 117 openmask &= ~(1 << i); 118 if (nlp->d_npartitions <= i) 119 return (EBUSY); 120 opp = &olp->d_partitions[i]; 121 npp = &nlp->d_partitions[i]; 122 if (npp->p_offset != opp->p_offset || npp->p_size < opp->p_size) 123 return (EBUSY); 124 /* 125 * Copy internally-set partition information 126 * if new label doesn't include it. XXX 127 */ 128 if (npp->p_fstype == FS_UNUSED && opp->p_fstype != FS_UNUSED) { 129 npp->p_fstype = opp->p_fstype; 130 npp->p_fsize = opp->p_fsize; 131 npp->p_frag = opp->p_frag; 132 npp->p_cpg = opp->p_cpg; 133 } 134 } 135 nlp->d_checksum = 0; 136 nlp->d_checksum = dkcksum(nlp); 137 *olp = *nlp; 138 return (0); 139} 140 141/* encoding of disk minor numbers, should be elsewhere... */ 142#define dkunit(dev) (minor(dev) >> 3) 143#define dkpart(dev) (minor(dev) & 07) 144#define dkminor(unit, part) (((unit) << 3) | (part)) 145 146/* 147 * Write disk label back to device after modification. 148 */ 149writedisklabel(dev, strat, lp, osdep) 150 dev_t dev; 151 void (*strat)(); 152 register struct disklabel *lp; 153 struct cpu_disklabel *osdep; 154{ 155 struct buf *bp; 156 struct disklabel *dlp; 157 int labelpart; 158 int error = 0; 159 160 labelpart = dkpart(dev); 161 if (lp->d_partitions[labelpart].p_offset != 0) { 162 if (lp->d_partitions[0].p_offset != 0) 163 return (EXDEV); /* not quite right */ 164 labelpart = 0; 165 } 166 bp = geteblk((int)lp->d_secsize); 167 bp->b_dev = makedev(major(dev), dkminor(dkunit(dev), labelpart)); 168 bp->b_blkno = LABELSECTOR; 169 bp->b_bcount = lp->d_secsize; 170 bp->b_flags = B_READ; 171 (*strat)(bp); 172 if (error = biowait(bp)) 173 goto done; 174 for (dlp = (struct disklabel *)bp->b_un.b_addr; 175 dlp <= (struct disklabel *) 176 (bp->b_un.b_addr + lp->d_secsize - sizeof(*dlp)); 177 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { 178 if (dlp->d_magic == DISKMAGIC && dlp->d_magic2 == DISKMAGIC && 179 dkcksum(dlp) == 0) { 180 *dlp = *lp; 181 bp->b_flags = B_WRITE; 182 (*strat)(bp); 183 error = biowait(bp); 184 goto done; 185 } 186 } 187 error = ESRCH; 188done: 189 brelse(bp); 190 return (error); 191} 192