| 1 | /* ffs_inode.c 4.7 81/11/08 */ |
| 2 | |
| 3 | #include "../h/param.h" |
| 4 | #include "../h/systm.h" |
| 5 | #include "../h/mount.h" |
| 6 | #include "../h/dir.h" |
| 7 | #include "../h/user.h" |
| 8 | #include "../h/inode.h" |
| 9 | #include "../h/ino.h" |
| 10 | #include "../h/filsys.h" |
| 11 | #include "../h/conf.h" |
| 12 | #include "../h/buf.h" |
| 13 | #include "../h/inline.h" |
| 14 | |
| 15 | #define INOHSZ 63 |
| 16 | #define INOHASH(dev,ino) (((dev)+(ino))%INOHSZ) |
| 17 | short inohash[INOHSZ]; |
| 18 | short ifreel; |
| 19 | |
| 20 | /* |
| 21 | * Initialize hash links for inodes |
| 22 | * and build inode free list. |
| 23 | */ |
| 24 | ihinit() |
| 25 | { |
| 26 | register int i; |
| 27 | register struct inode *ip = inode; |
| 28 | |
| 29 | ifreel = 0; |
| 30 | for (i = 0; i < ninode-1; i++, ip++) |
| 31 | ip->i_hlink = i+1; |
| 32 | ip->i_hlink = -1; |
| 33 | for (i = 0; i < INOHSZ; i++) |
| 34 | inohash[i] = -1; |
| 35 | } |
| 36 | |
| 37 | /* |
| 38 | * Find an inode if it is incore. |
| 39 | * This is the equivalent, for inodes, |
| 40 | * of ``incore'' in bio.c or ``pfind'' in subr.c. |
| 41 | */ |
| 42 | struct inode * |
| 43 | ifind(dev, ino) |
| 44 | dev_t dev; |
| 45 | ino_t ino; |
| 46 | { |
| 47 | register struct inode *ip; |
| 48 | |
| 49 | for (ip = &inode[inohash[INOHASH(dev,ino)]]; ip != &inode[-1]; |
| 50 | ip = &inode[ip->i_hlink]) |
| 51 | if (ino==ip->i_number && dev==ip->i_dev) |
| 52 | return (ip); |
| 53 | return ((struct inode *)0); |
| 54 | } |
| 55 | |
| 56 | /* |
| 57 | * Look up an inode by device,inumber. |
| 58 | * If it is in core (in the inode structure), |
| 59 | * honor the locking protocol. |
| 60 | * If it is not in core, read it in from the |
| 61 | * specified device. |
| 62 | * If the inode is mounted on, perform |
| 63 | * the indicated indirection. |
| 64 | * In all cases, a pointer to a locked |
| 65 | * inode structure is returned. |
| 66 | * |
| 67 | * panic: no imt -- if the mounted file |
| 68 | * system is not in the mount table. |
| 69 | * "cannot happen" |
| 70 | */ |
| 71 | struct inode * |
| 72 | iget(dev, ino) |
| 73 | dev_t dev; |
| 74 | ino_t ino; |
| 75 | { |
| 76 | register struct inode *ip; |
| 77 | register struct mount *mp; |
| 78 | register struct buf *bp; |
| 79 | register struct dinode *dp; |
| 80 | register int slot; |
| 81 | |
| 82 | loop: |
| 83 | slot = INOHASH(dev, ino); |
| 84 | ip = &inode[inohash[slot]]; |
| 85 | while (ip != &inode[-1]) { |
| 86 | if (ino == ip->i_number && dev == ip->i_dev) { |
| 87 | if ((ip->i_flag&ILOCK) != 0) { |
| 88 | ip->i_flag |= IWANT; |
| 89 | sleep((caddr_t)ip, PINOD); |
| 90 | goto loop; |
| 91 | } |
| 92 | if ((ip->i_flag&IMOUNT) != 0) { |
| 93 | for(mp = &mount[0]; mp < &mount[NMOUNT]; mp++) |
| 94 | if (mp->m_inodp == ip) { |
| 95 | dev = mp->m_dev; |
| 96 | ino = ROOTINO; |
| 97 | goto loop; |
| 98 | } |
| 99 | panic("no imt"); |
| 100 | } |
| 101 | ip->i_count++; |
| 102 | ip->i_flag |= ILOCK; |
| 103 | return(ip); |
| 104 | } |
| 105 | ip = &inode[ip->i_hlink]; |
| 106 | } |
| 107 | if (ifreel < 0) { |
| 108 | tablefull("inode"); |
| 109 | u.u_error = ENFILE; |
| 110 | return(NULL); |
| 111 | } |
| 112 | ip = &inode[ifreel]; |
| 113 | ifreel = ip->i_hlink; |
| 114 | ip->i_hlink = inohash[slot]; |
| 115 | inohash[slot] = ip - inode; |
| 116 | ip->i_dev = dev; |
| 117 | ip->i_number = ino; |
| 118 | ip->i_flag = ILOCK; |
| 119 | ip->i_count++; |
| 120 | ip->i_un.i_lastr = 0; |
| 121 | bp = bread(dev, itod(ino)); |
| 122 | /* |
| 123 | * Check I/O errors |
| 124 | */ |
| 125 | if ((bp->b_flags&B_ERROR) != 0) { |
| 126 | brelse(bp); |
| 127 | iput(ip); |
| 128 | return(NULL); |
| 129 | } |
| 130 | dp = bp->b_un.b_dino; |
| 131 | dp += itoo(ino); |
| 132 | iexpand(ip, dp); |
| 133 | brelse(bp); |
| 134 | return(ip); |
| 135 | } |
| 136 | |
| 137 | iexpand(ip, dp) |
| 138 | register struct inode *ip; |
| 139 | register struct dinode *dp; |
| 140 | { |
| 141 | register char *p1, *p2; |
| 142 | register int i; |
| 143 | |
| 144 | ip->i_mode = dp->di_mode; |
| 145 | ip->i_nlink = dp->di_nlink; |
| 146 | ip->i_uid = dp->di_uid; |
| 147 | ip->i_gid = dp->di_gid; |
| 148 | ip->i_size = dp->di_size; |
| 149 | p1 = (char *)ip->i_un.i_addr; |
| 150 | p2 = (char *)dp->di_addr; |
| 151 | for(i=0; i<NADDR; i++) { |
| 152 | *p1++ = *p2++; |
| 153 | *p1++ = *p2++; |
| 154 | *p1++ = *p2++; |
| 155 | *p1++ = 0; |
| 156 | } |
| 157 | } |
| 158 | |
| 159 | /* |
| 160 | * Decrement reference count of |
| 161 | * an inode structure. |
| 162 | * On the last reference, |
| 163 | * write the inode out and if necessary, |
| 164 | * truncate and deallocate the file. |
| 165 | */ |
| 166 | iput(ip) |
| 167 | register struct inode *ip; |
| 168 | { |
| 169 | register int i, x; |
| 170 | register struct inode *jp; |
| 171 | |
| 172 | if (ip->i_count == 1) { |
| 173 | ip->i_flag |= ILOCK; |
| 174 | if (ip->i_nlink <= 0) { |
| 175 | itrunc(ip); |
| 176 | ip->i_mode = 0; |
| 177 | ip->i_flag |= IUPD|ICHG; |
| 178 | ifree(ip->i_dev, ip->i_number); |
| 179 | } |
| 180 | IUPDAT(ip, &time, &time, 0); |
| 181 | irele(ip); |
| 182 | i = INOHASH(ip->i_dev, ip->i_number); |
| 183 | x = ip - inode; |
| 184 | if (inohash[i] == x) { |
| 185 | inohash[i] = ip->i_hlink; |
| 186 | } else { |
| 187 | for (jp = &inode[inohash[i]]; jp != &inode[-1]; |
| 188 | jp = &inode[jp->i_hlink]) |
| 189 | if (jp->i_hlink == x) { |
| 190 | jp->i_hlink = ip->i_hlink; |
| 191 | goto done; |
| 192 | } |
| 193 | panic("iput"); |
| 194 | } |
| 195 | done: |
| 196 | ip->i_hlink = ifreel; |
| 197 | ifreel = x; |
| 198 | ip->i_flag = 0; |
| 199 | ip->i_number = 0; |
| 200 | } else |
| 201 | irele(ip); |
| 202 | ip->i_count--; |
| 203 | } |
| 204 | |
| 205 | /* |
| 206 | * Check accessed and update flags on |
| 207 | * an inode structure. |
| 208 | * If any is on, update the inode |
| 209 | * with the current time. |
| 210 | * If waitfor is given, then must insure |
| 211 | * i/o order so wait for write to complete. |
| 212 | */ |
| 213 | iupdat(ip, ta, tm, waitfor) |
| 214 | register struct inode *ip; |
| 215 | time_t *ta, *tm; |
| 216 | int waitfor; |
| 217 | { |
| 218 | register struct buf *bp; |
| 219 | struct dinode *dp; |
| 220 | register char *p1, *p2; |
| 221 | register int i; |
| 222 | |
| 223 | if ((ip->i_flag&(IUPD|IACC|ICHG)) != 0) { |
| 224 | if (getfs(ip->i_dev)->s_ronly) |
| 225 | return; |
| 226 | bp = bread(ip->i_dev, itod(ip->i_number)); |
| 227 | if (bp->b_flags & B_ERROR) { |
| 228 | brelse(bp); |
| 229 | return; |
| 230 | } |
| 231 | dp = bp->b_un.b_dino; |
| 232 | dp += itoo(ip->i_number); |
| 233 | dp->di_mode = ip->i_mode; |
| 234 | dp->di_nlink = ip->i_nlink; |
| 235 | dp->di_uid = ip->i_uid; |
| 236 | dp->di_gid = ip->i_gid; |
| 237 | dp->di_size = ip->i_size; |
| 238 | p1 = (char *)dp->di_addr; |
| 239 | p2 = (char *)ip->i_un.i_addr; |
| 240 | for(i=0; i<NADDR; i++) { |
| 241 | *p1++ = *p2++; |
| 242 | *p1++ = *p2++; |
| 243 | *p1++ = *p2++; |
| 244 | if (*p2++ != 0) |
| 245 | printf("iaddress > 2^24\n"); |
| 246 | } |
| 247 | if (ip->i_flag&IACC) |
| 248 | dp->di_atime = *ta; |
| 249 | if (ip->i_flag&IUPD) |
| 250 | dp->di_mtime = *tm; |
| 251 | if (ip->i_flag&ICHG) |
| 252 | dp->di_ctime = time; |
| 253 | ip->i_flag &= ~(IUPD|IACC|ICHG); |
| 254 | if (waitfor) |
| 255 | bwrite(bp); |
| 256 | else |
| 257 | bdwrite(bp); |
| 258 | } |
| 259 | } |
| 260 | |
| 261 | /* |
| 262 | * Free all the disk blocks associated |
| 263 | * with the specified inode structure. |
| 264 | * The blocks of the file are removed |
| 265 | * in reverse order. This FILO |
| 266 | * algorithm will tend to maintain |
| 267 | * a contiguous free list much longer |
| 268 | * than FIFO. |
| 269 | */ |
| 270 | itrunc(ip) |
| 271 | register struct inode *ip; |
| 272 | { |
| 273 | register i; |
| 274 | dev_t dev; |
| 275 | daddr_t bn; |
| 276 | struct inode itmp; |
| 277 | |
| 278 | i = ip->i_mode & IFMT; |
| 279 | if (i!=IFREG && i!=IFDIR) |
| 280 | return; |
| 281 | |
| 282 | /* |
| 283 | * Clean inode on disk before freeing blocks |
| 284 | * to insure no duplicates if system crashes. |
| 285 | */ |
| 286 | itmp = *ip; |
| 287 | itmp.i_size = 0; |
| 288 | for (i = 0; i < NADDR; i++) |
| 289 | itmp.i_un.i_addr[i] = 0; |
| 290 | itmp.i_flag |= ICHG|IUPD; |
| 291 | iupdat(&itmp, &time, &time, 1); |
| 292 | ip->i_flag &= ~(IUPD|IACC|ICHG); |
| 293 | |
| 294 | /* |
| 295 | * Now return blocks to free list... if machine |
| 296 | * crashes, they will be harmless MISSING blocks. |
| 297 | */ |
| 298 | dev = ip->i_dev; |
| 299 | for(i=NADDR-1; i>=0; i--) { |
| 300 | bn = ip->i_un.i_addr[i]; |
| 301 | if (bn == (daddr_t)0) |
| 302 | continue; |
| 303 | ip->i_un.i_addr[i] = (daddr_t)0; |
| 304 | switch(i) { |
| 305 | |
| 306 | default: |
| 307 | free(dev, bn); |
| 308 | break; |
| 309 | |
| 310 | case NADDR-3: |
| 311 | tloop(dev, bn, 0, 0); |
| 312 | break; |
| 313 | |
| 314 | case NADDR-2: |
| 315 | tloop(dev, bn, 1, 0); |
| 316 | break; |
| 317 | |
| 318 | case NADDR-1: |
| 319 | tloop(dev, bn, 1, 1); |
| 320 | } |
| 321 | } |
| 322 | ip->i_size = 0; |
| 323 | /* |
| 324 | * Inode was written and flags updated above. |
| 325 | * No need to modify flags here. |
| 326 | */ |
| 327 | } |
| 328 | |
| 329 | tloop(dev, bn, f1, f2) |
| 330 | dev_t dev; |
| 331 | daddr_t bn; |
| 332 | { |
| 333 | register i; |
| 334 | register struct buf *bp; |
| 335 | register daddr_t *bap; |
| 336 | daddr_t nb; |
| 337 | |
| 338 | bp = NULL; |
| 339 | for(i=NINDIR-1; i>=0; i--) { |
| 340 | if (bp == NULL) { |
| 341 | bp = bread(dev, bn); |
| 342 | if (bp->b_flags & B_ERROR) { |
| 343 | brelse(bp); |
| 344 | return; |
| 345 | } |
| 346 | bap = bp->b_un.b_daddr; |
| 347 | } |
| 348 | nb = bap[i]; |
| 349 | if (nb == (daddr_t)0) |
| 350 | continue; |
| 351 | if (f1) { |
| 352 | brelse(bp); |
| 353 | bp = NULL; |
| 354 | tloop(dev, nb, f2, 0); |
| 355 | } else |
| 356 | free(dev, nb); |
| 357 | } |
| 358 | if (bp != NULL) |
| 359 | brelse(bp); |
| 360 | free(dev, bn); |
| 361 | } |
| 362 | |
| 363 | /* |
| 364 | * Make a new file. |
| 365 | */ |
| 366 | struct inode * |
| 367 | maknode(mode) |
| 368 | { |
| 369 | register struct inode *ip; |
| 370 | |
| 371 | ip = ialloc(u.u_pdir->i_dev); |
| 372 | if (ip == NULL) { |
| 373 | iput(u.u_pdir); |
| 374 | return(NULL); |
| 375 | } |
| 376 | ip->i_flag |= IACC|IUPD|ICHG; |
| 377 | if ((mode&IFMT) == 0) |
| 378 | mode |= IFREG; |
| 379 | ip->i_mode = mode & ~u.u_cmask; |
| 380 | ip->i_nlink = 1; |
| 381 | ip->i_uid = u.u_uid; |
| 382 | ip->i_gid = u.u_gid; |
| 383 | |
| 384 | /* |
| 385 | * Make sure inode goes to disk before directory entry. |
| 386 | */ |
| 387 | iupdat(ip, &time, &time, 1); |
| 388 | |
| 389 | wdir(ip); |
| 390 | return(ip); |
| 391 | } |
| 392 | |
| 393 | /* |
| 394 | * Write a directory entry with |
| 395 | * parameters left as side effects |
| 396 | * to a call to namei. |
| 397 | */ |
| 398 | wdir(ip) |
| 399 | struct inode *ip; |
| 400 | { |
| 401 | |
| 402 | u.u_dent.d_ino = ip->i_number; |
| 403 | bcopy((caddr_t)u.u_dbuf, (caddr_t)u.u_dent.d_name, DIRSIZ); |
| 404 | u.u_count = sizeof(struct direct); |
| 405 | u.u_segflg = 1; |
| 406 | u.u_base = (caddr_t)&u.u_dent; |
| 407 | writei(u.u_pdir); |
| 408 | iput(u.u_pdir); |
| 409 | } |
| 410 | |
| 411 | #ifdef ilock |
| 412 | #undef ilock |
| 413 | #endif |
| 414 | #ifdef irele |
| 415 | #undef irele |
| 416 | #endif |
| 417 | /* |
| 418 | * Lock an inode. If its already locked, set the WANT bit and sleep. |
| 419 | */ |
| 420 | ilock(ip) |
| 421 | register struct inode *ip; |
| 422 | { |
| 423 | |
| 424 | while (ip->i_flag&ILOCK) { |
| 425 | ip->i_flag |= IWANT; |
| 426 | sleep((caddr_t)ip, PINOD); |
| 427 | } |
| 428 | ip->i_flag |= ILOCK; |
| 429 | } |
| 430 | |
| 431 | /* |
| 432 | * Unlock an inode. If WANT bit is on, wakeup. |
| 433 | */ |
| 434 | irele(ip) |
| 435 | register struct inode *ip; |
| 436 | { |
| 437 | |
| 438 | ip->i_flag &= ~ILOCK; |
| 439 | if (ip->i_flag&IWANT) { |
| 440 | ip->i_flag &= ~IWANT; |
| 441 | wakeup((caddr_t)ip); |
| 442 | } |
| 443 | } |