1 /* 2 * Copyright (c) 1982, 1986, 1988 Regents of the University of California. 3 * All rights reserved. The Berkeley software License Agreement 4 * specifies the terms and conditions for redistribution. 5 * 6 * @(#)ufs_disksubr.c 7.10 (Berkeley) 06/11/88 7 */ 8 9 #include "param.h" 10 #include "systm.h" 11 #include "buf.h" 12 #include "disklabel.h" 13 #include "syslog.h" 14 15 #include "dir.h" 16 #include "user.h" 17 18 /* 19 * Seek sort for disks. We depend on the driver 20 * which calls us using b_resid as the current cylinder number. 21 * 22 * The argument dp structure holds a b_actf activity chain pointer 23 * on which we keep two queues, sorted in ascending cylinder order. 24 * The first queue holds those requests which are positioned after 25 * the current cylinder (in the first request); the second holds 26 * requests which came in after their cylinder number was passed. 27 * Thus we implement a one way scan, retracting after reaching the 28 * end of the drive to the first request on the second queue, 29 * at which time it becomes the first queue. 30 * 31 * A one-way scan is natural because of the way UNIX read-ahead 32 * blocks are allocated. 33 */ 34 35 #define b_cylin b_resid 36 37 disksort(dp, bp) 38 register struct buf *dp, *bp; 39 { 40 register struct buf *ap; 41 42 /* 43 * If nothing on the activity queue, then 44 * we become the only thing. 45 */ 46 ap = dp->b_actf; 47 if(ap == NULL) { 48 dp->b_actf = bp; 49 dp->b_actl = bp; 50 bp->av_forw = NULL; 51 return; 52 } 53 /* 54 * If we lie after the first (currently active) 55 * request, then we must locate the second request list 56 * and add ourselves to it. 57 */ 58 if (bp->b_cylin < ap->b_cylin) { 59 while (ap->av_forw) { 60 /* 61 * Check for an ``inversion'' in the 62 * normally ascending cylinder numbers, 63 * indicating the start of the second request list. 64 */ 65 if (ap->av_forw->b_cylin < ap->b_cylin) { 66 /* 67 * Search the second request list 68 * for the first request at a larger 69 * cylinder number. We go before that; 70 * if there is no such request, we go at end. 71 */ 72 do { 73 if (bp->b_cylin < ap->av_forw->b_cylin) 74 goto insert; 75 if (bp->b_cylin == ap->av_forw->b_cylin && 76 bp->b_blkno < ap->av_forw->b_blkno) 77 goto insert; 78 ap = ap->av_forw; 79 } while (ap->av_forw); 80 goto insert; /* after last */ 81 } 82 ap = ap->av_forw; 83 } 84 /* 85 * No inversions... we will go after the last, and 86 * be the first request in the second request list. 87 */ 88 goto insert; 89 } 90 /* 91 * Request is at/after the current request... 92 * sort in the first request list. 93 */ 94 while (ap->av_forw) { 95 /* 96 * We want to go after the current request 97 * if there is an inversion after it (i.e. it is 98 * the end of the first request list), or if 99 * the next request is a larger cylinder than our request. 100 */ 101 if (ap->av_forw->b_cylin < ap->b_cylin || 102 bp->b_cylin < ap->av_forw->b_cylin || 103 (bp->b_cylin == ap->av_forw->b_cylin && 104 bp->b_blkno < ap->av_forw->b_blkno)) 105 goto insert; 106 ap = ap->av_forw; 107 } 108 /* 109 * Neither a second list nor a larger 110 * request... we go at the end of the first list, 111 * which is the same as the end of the whole schebang. 112 */ 113 insert: 114 bp->av_forw = ap->av_forw; 115 ap->av_forw = bp; 116 if (ap == dp->b_actl) 117 dp->b_actl = bp; 118 } 119 120 /* 121 * Attempt to read a disk label from a device 122 * using the indicated stategy routine. 123 * The label must be partly set up before this: 124 * secpercyl and anything required in the strategy routine 125 * (e.g., sector size) must be filled in before calling us. 126 * Returns null on success and an error string on failure. 127 */ 128 char * 129 readdisklabel(dev, strat, lp) 130 dev_t dev; 131 int (*strat)(); 132 register struct disklabel *lp; 133 { 134 register struct buf *bp; 135 struct disklabel *dlp; 136 char *msg = NULL; 137 138 if (lp->d_secperunit == 0) 139 lp->d_secperunit = 0x1fffffff; 140 lp->d_npartitions = 1; 141 if (lp->d_partitions[0].p_size == 0) 142 lp->d_partitions[0].p_size = 0x1fffffff; 143 lp->d_partitions[0].p_offset = 0; 144 145 bp = geteblk((int)lp->d_secsize); 146 bp->b_dev = dev; 147 bp->b_blkno = LABELSECTOR; 148 bp->b_bcount = lp->d_secsize; 149 bp->b_flags = B_BUSY | B_READ; 150 bp->b_cylin = LABELSECTOR / lp->d_secpercyl; 151 (*strat)(bp); 152 biowait(bp); 153 if (bp->b_flags & B_ERROR) { 154 u.u_error = 0; /* XXX */ 155 msg = "I/O error"; 156 } else for (dlp = (struct disklabel *)bp->b_un.b_addr; 157 dlp <= (struct disklabel *)(bp->b_un.b_addr+DEV_BSIZE-sizeof(*dlp)); 158 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { 159 if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) { 160 if (msg == NULL) 161 msg = "no disk label"; 162 } else if (dkcksum(dlp) != 0) 163 msg = "disk label corrupted"; 164 else { 165 *lp = *dlp; 166 msg = NULL; 167 break; 168 } 169 } 170 if (lp->d_npartitions > MAXPARTITIONS) 171 lp->d_npartitions = MAXPARTITIONS; 172 bp->b_flags = B_INVAL | B_AGE; 173 brelse(bp); 174 return (msg); 175 } 176 177 /* 178 * Check new disk label for sensibility 179 * before setting it. 180 */ 181 setdisklabel(olp, nlp, openmask) 182 register struct disklabel *olp, *nlp; 183 u_long openmask; 184 { 185 register i; 186 register struct partition *opp, *npp; 187 188 if (nlp->d_magic != DISKMAGIC || nlp->d_magic2 != DISKMAGIC || 189 dkcksum(nlp) != 0) 190 return (EINVAL); 191 while ((i = ffs((long)openmask)) != 0) { 192 i--; 193 openmask &= ~(1 << i); 194 if (nlp->d_npartitions <= i) 195 return (EBUSY); 196 opp = &olp->d_partitions[i]; 197 npp = &nlp->d_partitions[i]; 198 if (npp->p_offset != opp->p_offset || npp->p_size < opp->p_size) 199 return (EBUSY); 200 /* 201 * Copy internally-set partition information 202 * if new label doesn't include it. XXX 203 */ 204 if (npp->p_fstype == FS_UNUSED && opp->p_fstype != FS_UNUSED) { 205 npp->p_fstype = opp->p_fstype; 206 npp->p_fsize = opp->p_fsize; 207 npp->p_frag = opp->p_frag; 208 npp->p_cpg = opp->p_cpg; 209 } 210 } 211 nlp->d_checksum = 0; 212 nlp->d_checksum = dkcksum(nlp); 213 *olp = *nlp; 214 return (0); 215 } 216 217 /* encoding of disk minor numbers, should be elsewhere... */ 218 #define dkunit(dev) (minor(dev) >> 3) 219 #define dkpart(dev) (minor(dev) & 07) 220 #define dkminor(unit, part) (((unit) << 3) | (part)) 221 222 /* 223 * Write disk label back to device after modification. 224 */ 225 writedisklabel(dev, strat, lp) 226 dev_t dev; 227 int (*strat)(); 228 register struct disklabel *lp; 229 { 230 struct buf *bp; 231 struct disklabel *dlp; 232 int labelpart; 233 int error = 0; 234 235 labelpart = dkpart(dev); 236 if (lp->d_partitions[labelpart].p_offset != 0) { 237 if (lp->d_partitions[0].p_offset != 0) 238 return (EXDEV); /* not quite right */ 239 labelpart = 0; 240 } 241 bp = geteblk((int)lp->d_secsize); 242 bp->b_dev = makedev(major(dev), dkminor(dkunit(dev), labelpart)); 243 bp->b_blkno = LABELSECTOR; 244 bp->b_bcount = lp->d_secsize; 245 bp->b_flags = B_READ; 246 (*strat)(bp); 247 biowait(bp); 248 if (bp->b_flags & B_ERROR) { 249 error = u.u_error; /* XXX */ 250 u.u_error = 0; 251 goto done; 252 } 253 for (dlp = (struct disklabel *)bp->b_un.b_addr; 254 dlp <= (struct disklabel *) 255 (bp->b_un.b_addr + lp->d_secsize - sizeof(*dlp)); 256 dlp = (struct disklabel *)((char *)dlp + sizeof(long))) { 257 if (dlp->d_magic == DISKMAGIC && dlp->d_magic2 == DISKMAGIC && 258 dkcksum(dlp) == 0) { 259 *dlp = *lp; 260 bp->b_flags = B_WRITE; 261 (*strat)(bp); 262 biowait(bp); 263 if (bp->b_flags & B_ERROR) { 264 error = u.u_error; /* XXX */ 265 u.u_error = 0; 266 } 267 goto done; 268 } 269 } 270 error = ESRCH; 271 done: 272 brelse(bp); 273 return (error); 274 } 275 276 /* 277 * Compute checksum for disk label. 278 */ 279 dkcksum(lp) 280 register struct disklabel *lp; 281 { 282 register u_short *start, *end; 283 register u_short sum = 0; 284 285 start = (u_short *)lp; 286 end = (u_short *)&lp->d_partitions[lp->d_npartitions]; 287 while (start < end) 288 sum ^= *start++; 289 return (sum); 290 } 291 292 /* 293 * Disk error is the preface to plaintive error messages 294 * about failing disk transfers. It prints messages of the form 295 296 hp0g: hard error reading fsbn 12345 of 12344-12347 (hp0 bn %d cn %d tn %d sn %d) 297 298 * if the offset of the error in the transfer and a disk label 299 * are both available. blkdone should be -1 if the position of the error 300 * is unknown; the disklabel pointer may be null from drivers that have not 301 * been converted to use them. The message is printed with printf 302 * if pri is LOG_PRINTF, otherwise it uses log at the specified priority. 303 * The message should be completed (with at least a newline) with printf 304 * or addlog, respectively. There is no trailing space. 305 */ 306 diskerr(bp, dname, what, pri, blkdone, lp) 307 register struct buf *bp; 308 char *dname, *what; 309 int pri, blkdone; 310 register struct disklabel *lp; 311 { 312 int unit = dkunit(bp->b_dev), part = dkpart(bp->b_dev); 313 register int (*pr)(), sn; 314 char partname = 'a' + part; 315 extern printf(), addlog(); 316 317 if (pri != LOG_PRINTF) { 318 log(pri, ""); 319 pr = addlog; 320 } else 321 pr = printf; 322 (*pr)("%s%d%c: %s %sing fsbn ", dname, unit, partname, what, 323 bp->b_flags & B_READ ? "read" : "writ"); 324 sn = bp->b_blkno; 325 if (bp->b_bcount <= DEV_BSIZE) 326 (*pr)("%d", sn); 327 else { 328 if (blkdone >= 0) { 329 sn += blkdone; 330 (*pr)("%d of ", sn); 331 } 332 (*pr)("%d-%d", bp->b_blkno, 333 bp->b_blkno + (bp->b_bcount - 1) / DEV_BSIZE); 334 } 335 if (lp && (blkdone >= 0 || bp->b_bcount <= lp->d_secsize)) { 336 #ifdef tahoe 337 sn *= DEV_BSIZE / lp->d_secsize; /* XXX */ 338 #endif 339 sn += lp->d_partitions[part].p_offset; 340 (*pr)(" (%s%d bn %d; cn %d", dname, unit, sn, 341 sn / lp->d_secpercyl); 342 sn %= lp->d_secpercyl; 343 (*pr)(" tn %d sn %d)", sn / lp->d_ntracks, sn % lp->d_ntracks); 344 } 345 } 346