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 are permitted 6 * provided that the above copyright notice and this paragraph are 7 * duplicated in all such forms and that any documentation, 8 * advertising materials, and other materials related to such 9 * distribution and use acknowledge that the software was developed 10 * by the University of California, Berkeley. The name of the 11 * University may not be used to endorse or promote products derived 12 * from this software without specific prior written permission. 13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16 * 17 * @(#)ufs_disksubr.c 7.13 (Berkeley) 01/02/90 18 */ 19 20 #include "param.h" 21 #include "systm.h" 22 #include "buf.h" 23 #include "disklabel.h" 24 #include "syslog.h" 25 #include "user.h" 26 27 /* 28 * Seek sort for disks. We depend on the driver 29 * which calls us using b_resid as the current cylinder number. 30 * 31 * The argument dp structure holds a b_actf activity chain pointer 32 * on which we keep two queues, sorted in ascending cylinder order. 33 * The first queue holds those requests which are positioned after 34 * the current cylinder (in the first request); the second holds 35 * requests which came in after their cylinder number was passed. 36 * Thus we implement a one way scan, retracting after reaching the 37 * end of the drive to the first request on the second queue, 38 * at which time it becomes the first queue. 39 * 40 * A one-way scan is natural because of the way UNIX read-ahead 41 * blocks are allocated. 42 */ 43 44 #define b_cylin b_resid 45 46 disksort(dp, bp) 47 register struct buf *dp, *bp; 48 { 49 register struct buf *ap; 50 51 /* 52 * If nothing on the activity queue, then 53 * we become the only thing. 54 */ 55 ap = dp->b_actf; 56 if(ap == NULL) { 57 dp->b_actf = bp; 58 dp->b_actl = bp; 59 bp->av_forw = NULL; 60 return; 61 } 62 /* 63 * If we lie after the first (currently active) 64 * request, then we must locate the second request list 65 * and add ourselves to it. 66 */ 67 if (bp->b_cylin < ap->b_cylin) { 68 while (ap->av_forw) { 69 /* 70 * Check for an ``inversion'' in the 71 * normally ascending cylinder numbers, 72 * indicating the start of the second request list. 73 */ 74 if (ap->av_forw->b_cylin < ap->b_cylin) { 75 /* 76 * Search the second request list 77 * for the first request at a larger 78 * cylinder number. We go before that; 79 * if there is no such request, we go at end. 80 */ 81 do { 82 if (bp->b_cylin < ap->av_forw->b_cylin) 83 goto insert; 84 if (bp->b_cylin == ap->av_forw->b_cylin && 85 bp->b_blkno < ap->av_forw->b_blkno) 86 goto insert; 87 ap = ap->av_forw; 88 } while (ap->av_forw); 89 goto insert; /* after last */ 90 } 91 ap = ap->av_forw; 92 } 93 /* 94 * No inversions... we will go after the last, and 95 * be the first request in the second request list. 96 */ 97 goto insert; 98 } 99 /* 100 * Request is at/after the current request... 101 * sort in the first request list. 102 */ 103 while (ap->av_forw) { 104 /* 105 * We want to go after the current request 106 * if there is an inversion after it (i.e. it is 107 * the end of the first request list), or if 108 * the next request is a larger cylinder than our request. 109 */ 110 if (ap->av_forw->b_cylin < ap->b_cylin || 111 bp->b_cylin < ap->av_forw->b_cylin || 112 (bp->b_cylin == ap->av_forw->b_cylin && 113 bp->b_blkno < ap->av_forw->b_blkno)) 114 goto insert; 115 ap = ap->av_forw; 116 } 117 /* 118 * Neither a second list nor a larger 119 * request... we go at the end of the first list, 120 * which is the same as the end of the whole schebang. 121 */ 122 insert: 123 bp->av_forw = ap->av_forw; 124 ap->av_forw = bp; 125 if (ap == dp->b_actl) 126 dp->b_actl = bp; 127 } 128 129 /* 130 * Attempt to read a disk label from a device 131 * using the indicated stategy routine. 132 * The label must be partly set up before this: 133 * secpercyl and anything required in the strategy routine 134 * (e.g., sector size) must be filled in before calling us. 135 * Returns null on success and an error string on failure. 136 */ 137 char * 138 readdisklabel(dev, strat, lp) 139 dev_t dev; 140 int (*strat)(); 141 register struct disklabel *lp; 142 { 143 register struct buf *bp; 144 struct disklabel *dlp; 145 char *msg = NULL; 146 147 if (lp->d_secperunit == 0) 148 lp->d_secperunit = 0x1fffffff; 149 lp->d_npartitions = 1; 150 if (lp->d_partitions[0].p_size == 0) 151 lp->d_partitions[0].p_size = 0x1fffffff; 152 lp->d_partitions[0].p_offset = 0; 153 154 bp = geteblk((int)lp->d_secsize); 155 bp->b_dev = dev; 156 bp->b_blkno = LABELSECTOR; 157 bp->b_bcount = lp->d_secsize; 158 bp->b_flags = B_BUSY | B_READ; 159 bp->b_cylin = LABELSECTOR / lp->d_secpercyl; 160 (*strat)(bp); 161 if (biowait(bp)) { 162 msg = "I/O error"; 163 } else for (dlp = (struct disklabel *)bp->b_un.b_addr; 164 dlp <= (struct disklabel *)(bp->b_un.b_addr+DEV_BSIZE-sizeof(*dlp)); 165 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { 166 if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) { 167 if (msg == NULL) 168 msg = "no disk label"; 169 } else if (dlp->d_npartitions > MAXPARTITIONS || 170 dkcksum(dlp) != 0) 171 msg = "disk label corrupted"; 172 else { 173 *lp = *dlp; 174 msg = NULL; 175 break; 176 } 177 } 178 bp->b_flags = B_INVAL | B_AGE; 179 brelse(bp); 180 return (msg); 181 } 182 183 /* 184 * Check new disk label for sensibility 185 * before setting it. 186 */ 187 setdisklabel(olp, nlp, openmask) 188 register struct disklabel *olp, *nlp; 189 u_long openmask; 190 { 191 register i; 192 register struct partition *opp, *npp; 193 194 if (nlp->d_magic != DISKMAGIC || nlp->d_magic2 != DISKMAGIC || 195 dkcksum(nlp) != 0) 196 return (EINVAL); 197 while ((i = ffs((long)openmask)) != 0) { 198 i--; 199 openmask &= ~(1 << i); 200 if (nlp->d_npartitions <= i) 201 return (EBUSY); 202 opp = &olp->d_partitions[i]; 203 npp = &nlp->d_partitions[i]; 204 if (npp->p_offset != opp->p_offset || npp->p_size < opp->p_size) 205 return (EBUSY); 206 /* 207 * Copy internally-set partition information 208 * if new label doesn't include it. XXX 209 */ 210 if (npp->p_fstype == FS_UNUSED && opp->p_fstype != FS_UNUSED) { 211 npp->p_fstype = opp->p_fstype; 212 npp->p_fsize = opp->p_fsize; 213 npp->p_frag = opp->p_frag; 214 npp->p_cpg = opp->p_cpg; 215 } 216 } 217 nlp->d_checksum = 0; 218 nlp->d_checksum = dkcksum(nlp); 219 *olp = *nlp; 220 return (0); 221 } 222 223 /* encoding of disk minor numbers, should be elsewhere... */ 224 #define dkunit(dev) (minor(dev) >> 3) 225 #define dkpart(dev) (minor(dev) & 07) 226 #define dkminor(unit, part) (((unit) << 3) | (part)) 227 228 /* 229 * Write disk label back to device after modification. 230 */ 231 writedisklabel(dev, strat, lp) 232 dev_t dev; 233 int (*strat)(); 234 register struct disklabel *lp; 235 { 236 struct buf *bp; 237 struct disklabel *dlp; 238 int labelpart; 239 int error = 0; 240 241 labelpart = dkpart(dev); 242 if (lp->d_partitions[labelpart].p_offset != 0) { 243 if (lp->d_partitions[0].p_offset != 0) 244 return (EXDEV); /* not quite right */ 245 labelpart = 0; 246 } 247 bp = geteblk((int)lp->d_secsize); 248 bp->b_dev = makedev(major(dev), dkminor(dkunit(dev), labelpart)); 249 bp->b_blkno = LABELSECTOR; 250 bp->b_bcount = lp->d_secsize; 251 bp->b_flags = B_READ; 252 (*strat)(bp); 253 if (error = biowait(bp)) 254 goto done; 255 for (dlp = (struct disklabel *)bp->b_un.b_addr; 256 dlp <= (struct disklabel *) 257 (bp->b_un.b_addr + lp->d_secsize - sizeof(*dlp)); 258 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { 259 if (dlp->d_magic == DISKMAGIC && dlp->d_magic2 == DISKMAGIC && 260 dkcksum(dlp) == 0) { 261 *dlp = *lp; 262 bp->b_flags = B_WRITE; 263 (*strat)(bp); 264 error = biowait(bp); 265 goto done; 266 } 267 } 268 error = ESRCH; 269 done: 270 brelse(bp); 271 return (error); 272 } 273 274 /* 275 * Compute checksum for disk label. 276 */ 277 dkcksum(lp) 278 register struct disklabel *lp; 279 { 280 register u_short *start, *end; 281 register u_short sum = 0; 282 283 start = (u_short *)lp; 284 end = (u_short *)&lp->d_partitions[lp->d_npartitions]; 285 while (start < end) 286 sum ^= *start++; 287 return (sum); 288 } 289 290 /* 291 * Disk error is the preface to plaintive error messages 292 * about failing disk transfers. It prints messages of the form 293 294 hp0g: hard error reading fsbn 12345 of 12344-12347 (hp0 bn %d cn %d tn %d sn %d) 295 296 * if the offset of the error in the transfer and a disk label 297 * are both available. blkdone should be -1 if the position of the error 298 * is unknown; the disklabel pointer may be null from drivers that have not 299 * been converted to use them. The message is printed with printf 300 * if pri is LOG_PRINTF, otherwise it uses log at the specified priority. 301 * The message should be completed (with at least a newline) with printf 302 * or addlog, respectively. There is no trailing space. 303 */ 304 diskerr(bp, dname, what, pri, blkdone, lp) 305 register struct buf *bp; 306 char *dname, *what; 307 int pri, blkdone; 308 register struct disklabel *lp; 309 { 310 int unit = dkunit(bp->b_dev), part = dkpart(bp->b_dev); 311 register int (*pr)(), sn; 312 char partname = 'a' + part; 313 extern printf(), addlog(); 314 315 if (pri != LOG_PRINTF) { 316 log(pri, ""); 317 pr = addlog; 318 } else 319 pr = printf; 320 (*pr)("%s%d%c: %s %sing fsbn ", dname, unit, partname, what, 321 bp->b_flags & B_READ ? "read" : "writ"); 322 sn = bp->b_blkno; 323 if (bp->b_bcount <= DEV_BSIZE) 324 (*pr)("%d", sn); 325 else { 326 if (blkdone >= 0) { 327 sn += blkdone; 328 (*pr)("%d of ", sn); 329 } 330 (*pr)("%d-%d", bp->b_blkno, 331 bp->b_blkno + (bp->b_bcount - 1) / DEV_BSIZE); 332 } 333 if (lp && (blkdone >= 0 || bp->b_bcount <= lp->d_secsize)) { 334 #ifdef tahoe 335 sn *= DEV_BSIZE / lp->d_secsize; /* XXX */ 336 #endif 337 sn += lp->d_partitions[part].p_offset; 338 (*pr)(" (%s%d bn %d; cn %d", dname, unit, sn, 339 sn / lp->d_secpercyl); 340 sn %= lp->d_secpercyl; 341 (*pr)(" tn %d sn %d)", sn / lp->d_nsectors, sn % lp->d_nsectors); 342 } 343 } 344