Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_disklabel.c
Version:
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1 /* 2 * Copyright (c) 1982, 1986, 1988, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)ufs_disksubr.c 8.5 (Berkeley) 1/21/94 39 * $FreeBSD: releng/5.0/sys/kern/subr_disklabel.c 103714 2002-09-20 19:36:05Z phk $ 40 */ 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/stdint.h> 45 #include <sys/bio.h> 46 #include <sys/buf.h> 47 #include <sys/conf.h> 48 #include <sys/kernel.h> 49 #include <sys/disk.h> 50 #include <sys/disklabel.h> 51 #include <sys/syslog.h> 52 53 /* 54 * Attempt to read a disk label from a device using the indicated strategy 55 * routine. The label must be partly set up before this: secpercyl, secsize 56 * and anything required in the strategy routine (e.g., dummy bounds for the 57 * partition containing the label) must be filled in before calling us. 58 * Returns NULL on success and an error string on failure. 59 */ 60 char * 61 readdisklabel(dev, lp) 62 dev_t dev; 63 register struct disklabel *lp; 64 { 65 register struct buf *bp; 66 struct disklabel *dlp; 67 char *msg = NULL; 68 69 bp = geteblk((int)lp->d_secsize); 70 bp->b_dev = dev; 71 bp->b_blkno = LABELSECTOR * ((int)lp->d_secsize/DEV_BSIZE); 72 bp->b_bcount = lp->d_secsize; 73 bp->b_flags &= ~B_INVAL; 74 bp->b_iocmd = BIO_READ; 75 DEV_STRATEGY(bp, 1); 76 if (bufwait(bp)) 77 msg = "I/O error"; 78 else if (bp->b_resid != 0) 79 msg = "disk too small for a label"; 80 else for (dlp = (struct disklabel *)bp->b_data; 81 dlp <= (struct disklabel *)((char *)bp->b_data + 82 lp->d_secsize - sizeof(*dlp)); 83 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { 84 if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) { 85 if (msg == NULL) 86 msg = "no disk label"; 87 } else if (dlp->d_npartitions > MAXPARTITIONS || 88 dkcksum(dlp) != 0) 89 msg = "disk label corrupted"; 90 else { 91 *lp = *dlp; 92 msg = NULL; 93 break; 94 } 95 } 96 bp->b_flags |= B_INVAL | B_AGE; 97 brelse(bp); 98 return (msg); 99 } 100 101 /* 102 * Check new disk label for sensibility before setting it. 103 */ 104 int 105 setdisklabel(olp, nlp, openmask) 106 register struct disklabel *olp, *nlp; 107 u_long openmask; 108 { 109 register int i; 110 register struct partition *opp, *npp; 111 112 /* 113 * Check it is actually a disklabel we are looking at. 114 */ 115 if (nlp->d_magic != DISKMAGIC || nlp->d_magic2 != DISKMAGIC || 116 dkcksum(nlp) != 0) 117 return (EINVAL); 118 /* 119 * For each partition that we think is open, 120 */ 121 while ((i = ffs((long)openmask)) != 0) { 122 i--; 123 /* 124 * Check it is not changing.... 125 */ 126 openmask &= ~(1 << i); 127 if (nlp->d_npartitions <= i) 128 return (EBUSY); 129 opp = &olp->d_partitions[i]; 130 npp = &nlp->d_partitions[i]; 131 if (npp->p_offset != opp->p_offset || npp->p_size < opp->p_size) 132 return (EBUSY); 133 /* 134 * Copy internally-set partition information 135 * if new label doesn't include it. XXX 136 * (If we are using it then we had better stay the same type) 137 * This is possibly dubious, as someone else noted (XXX) 138 */ 139 if (npp->p_fstype == FS_UNUSED && opp->p_fstype != FS_UNUSED) { 140 npp->p_fstype = opp->p_fstype; 141 npp->p_fsize = opp->p_fsize; 142 npp->p_frag = opp->p_frag; 143 npp->p_cpg = opp->p_cpg; 144 } 145 } 146 nlp->d_checksum = 0; 147 nlp->d_checksum = dkcksum(nlp); 148 *olp = *nlp; 149 return (0); 150 } 151 152 /* 153 * Write disk label back to device after modification. 154 */ 155 int 156 writedisklabel(dev, lp) 157 dev_t dev; 158 register struct disklabel *lp; 159 { 160 struct buf *bp; 161 struct disklabel *dlp; 162 int error = 0; 163 164 if (lp->d_partitions[RAW_PART].p_offset != 0) 165 return (EXDEV); /* not quite right */ 166 bp = geteblk((int)lp->d_secsize); 167 bp->b_dev = dkmodpart(dev, RAW_PART); 168 bp->b_blkno = LABELSECTOR * ((int)lp->d_secsize/DEV_BSIZE); 169 bp->b_bcount = lp->d_secsize; 170 #if 1 171 /* 172 * We read the label first to see if it's there, 173 * in which case we will put ours at the same offset into the block.. 174 * (I think this is stupid [Julian]) 175 * Note that you can't write a label out over a corrupted label! 176 * (also stupid.. how do you write the first one? by raw writes?) 177 */ 178 bp->b_flags &= ~B_INVAL; 179 bp->b_iocmd = BIO_READ; 180 DEV_STRATEGY(bp, 1); 181 error = bufwait(bp); 182 if (error) 183 goto done; 184 if (bp->b_resid != 0) { 185 error = ENOSPC; 186 goto done; 187 } 188 for (dlp = (struct disklabel *)bp->b_data; 189 dlp <= (struct disklabel *) 190 ((char *)bp->b_data + lp->d_secsize - sizeof(*dlp)); 191 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { 192 if (dlp->d_magic == DISKMAGIC && dlp->d_magic2 == DISKMAGIC && 193 dkcksum(dlp) == 0) { 194 *dlp = *lp; 195 bp->b_flags &= ~B_DONE; 196 bp->b_iocmd = BIO_WRITE; 197 #ifdef __alpha__ 198 alpha_fix_srm_checksum(bp); 199 #endif 200 DEV_STRATEGY(bp, 1); 201 error = bufwait(bp); 202 goto done; 203 } 204 } 205 error = ESRCH; 206 done: 207 #else 208 bzero(bp->b_data, lp->d_secsize); 209 dlp = (struct disklabel *)bp->b_data; 210 *dlp = *lp; 211 bp->b_flags &= ~B_INVAL; 212 bp->b_iocmd = BIO_WRITE; 213 DEV_STRATEGY(bp, 1); 214 error = bufwait(bp); 215 #endif 216 bp->b_flags |= B_INVAL | B_AGE; 217 brelse(bp); 218 return (error); 219 } 220 221 /* 222 * Determine the size of the transfer, and make sure it is 223 * within the boundaries of the partition. Adjust transfer 224 * if needed, and signal errors or early completion. 225 */ 226 int 227 bounds_check_with_label(struct bio *bp, struct disklabel *lp, int wlabel) 228 { 229 struct partition *p = lp->d_partitions + dkpart(bp->bio_dev); 230 int labelsect = lp->d_partitions[0].p_offset; 231 int maxsz = p->p_size, 232 sz = (bp->bio_bcount + DEV_BSIZE - 1) >> DEV_BSHIFT; 233 234 /* overwriting disk label ? */ 235 /* XXX should also protect bootstrap in first 8K */ 236 if (bp->bio_blkno + p->p_offset <= LABELSECTOR + labelsect && 237 #if LABELSECTOR != 0 238 bp->bio_blkno + p->p_offset + sz > LABELSECTOR + labelsect && 239 #endif 240 (bp->bio_cmd == BIO_WRITE) && wlabel == 0) { 241 bp->bio_error = EROFS; 242 goto bad; 243 } 244 245 #if defined(DOSBBSECTOR) && defined(notyet) 246 /* overwriting master boot record? */ 247 if (bp->bio_blkno + p->p_offset <= DOSBBSECTOR && 248 (bp->bio_cmd == BIO_WRITE) && wlabel == 0) { 249 bp->bio_error = EROFS; 250 goto bad; 251 } 252 #endif 253 254 /* beyond partition? */ 255 if (bp->bio_blkno < 0 || bp->bio_blkno + sz > maxsz) { 256 /* if exactly at end of disk, return an EOF */ 257 if (bp->bio_blkno == maxsz) { 258 bp->bio_resid = bp->bio_bcount; 259 return(0); 260 } 261 /* or truncate if part of it fits */ 262 sz = maxsz - bp->bio_blkno; 263 if (sz <= 0) { 264 bp->bio_error = EINVAL; 265 goto bad; 266 } 267 bp->bio_bcount = sz << DEV_BSHIFT; 268 } 269 270 bp->bio_pblkno = bp->bio_blkno + p->p_offset; 271 return(1); 272 273 bad: 274 bp->bio_flags |= BIO_ERROR; 275 return(-1); 276 } 277
Cache object: 6a438804dbc4a951ba3c8cae86e89a03
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