1 /* lfs_inode.c 4.35 83/05/21 */ 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/fs.h" 10 #include "../h/conf.h" 11 #include "../h/buf.h" 12 #ifdef QUOTA 13 #include "../h/quota.h" 14 #endif 15 #include "../h/kernel.h" 16 17 #define INOHSZ 63 18 #if ((INOHSZ&(INOHSZ-1)) == 0) 19 #define INOHASH(dev,ino) (((dev)+(ino))&(INOHSZ-1)) 20 #else 21 #define INOHASH(dev,ino) (((unsigned)((dev)+(ino)))%INOHSZ) 22 #endif 23 24 union ihead { /* inode LRU cache, Chris Maltby */ 25 union ihead *ih_head[2]; 26 struct inode *ih_chain[2]; 27 } ihead[INOHSZ]; 28 29 struct inode *ifreeh, **ifreet; 30 31 /* 32 * Initialize hash links for inodes 33 * and build inode free list. 34 */ 35 ihinit() 36 { 37 register int i; 38 register struct inode *ip = inode; 39 register union ihead *ih = ihead; 40 41 for (i = INOHSZ; --i >= 0; ih++) { 42 ih->ih_head[0] = ih; 43 ih->ih_head[1] = ih; 44 } 45 ifreeh = ip; 46 ifreet = &ip->i_freef; 47 ip->i_freeb = &ifreeh; 48 ip->i_forw = ip; 49 ip->i_back = ip; 50 for (i = ninode; --i > 0; ) { 51 ++ip; 52 ip->i_forw = ip; 53 ip->i_back = ip; 54 *ifreet = ip; 55 ip->i_freeb = ifreet; 56 ifreet = &ip->i_freef; 57 } 58 ip->i_freef = NULL; 59 } 60 61 #ifdef notdef 62 /* 63 * Find an inode if it is incore. 64 * This is the equivalent, for inodes, 65 * of ``incore'' in bio.c or ``pfind'' in subr.c. 66 */ 67 struct inode * 68 ifind(dev, ino) 69 dev_t dev; 70 ino_t ino; 71 { 72 register struct inode *ip; 73 register union ihead *ih; 74 75 ih = &ihead[INOHASH(dev, ino)]; 76 for (ip = ih->ih_chain[0]; ip != (struct inode *)ih; ip = ip->i_forw) 77 if (ino==ip->i_number && dev==ip->i_dev) 78 return (ip); 79 return ((struct inode *)0); 80 } 81 #endif notdef 82 83 /* 84 * Look up an inode by device,inumber. 85 * If it is in core (in the inode structure), 86 * honor the locking protocol. 87 * If it is not in core, read it in from the 88 * specified device. 89 * If the inode is mounted on, perform 90 * the indicated indirection. 91 * In all cases, a pointer to a locked 92 * inode structure is returned. 93 * 94 * panic: no imt -- if the mounted file 95 * system is not in the mount table. 96 * "cannot happen" 97 */ 98 struct inode * 99 iget(dev, fs, ino) 100 dev_t dev; 101 register struct fs *fs; 102 ino_t ino; 103 { 104 register struct inode *ip; 105 register union ihead *ih; 106 register struct mount *mp; 107 register struct buf *bp; 108 register struct dinode *dp; 109 register struct inode *iq; 110 111 loop: 112 if (getfs(dev) != fs) 113 panic("iget: bad fs"); 114 ih = &ihead[INOHASH(dev, ino)]; 115 for (ip = ih->ih_chain[0]; ip != (struct inode *)ih; ip = ip->i_forw) 116 if (ino == ip->i_number && dev == ip->i_dev) { 117 if ((ip->i_flag&ILOCKED) != 0) { 118 ip->i_flag |= IWANT; 119 sleep((caddr_t)ip, PINOD); 120 goto loop; 121 } 122 if ((ip->i_flag&IMOUNT) != 0) { 123 for (mp = &mount[0]; mp < &mount[NMOUNT]; mp++) 124 if(mp->m_inodp == ip) { 125 dev = mp->m_dev; 126 fs = mp->m_bufp->b_un.b_fs; 127 ino = ROOTINO; 128 goto loop; 129 } 130 panic("no imt"); 131 } 132 if (ip->i_count == 0) { /* ino on free list */ 133 if (iq = ip->i_freef) 134 iq->i_freeb = ip->i_freeb; 135 else 136 ifreet = ip->i_freeb; 137 *ip->i_freeb = iq; 138 ip->i_freef = NULL; 139 ip->i_freeb = NULL; 140 } 141 ip->i_count++; 142 ip->i_flag |= ILOCKED; 143 return(ip); 144 } 145 146 if ((ip = ifreeh) == NULL) { 147 tablefull("inode"); 148 u.u_error = ENFILE; 149 return(NULL); 150 } 151 if (iq = ip->i_freef) 152 iq->i_freeb = &ifreeh; 153 ifreeh = iq; 154 ip->i_freef = NULL; 155 ip->i_freeb = NULL; 156 /* 157 * Now to take inode off the hash chain it was on 158 * (initially, or after an iflush, it is on a "hash chain" 159 * consisting entirely of itself, and pointed to by no-one, 160 * but that doesn't matter), and put it on the chain for 161 * its new (ino, dev) pair 162 */ 163 remque(ip); 164 insque(ip, ih); 165 #ifdef QUOTA 166 dqrele(ip->i_dquot); 167 #endif 168 ip->i_dev = dev; 169 ip->i_fs = fs; 170 ip->i_number = ino; 171 ip->i_flag = ILOCKED; 172 ip->i_count++; 173 ip->i_lastr = 0; 174 bp = bread(dev, fsbtodb(fs, itod(fs, ino)), (int)fs->fs_bsize); 175 /* 176 * Check I/O errors 177 */ 178 if ((bp->b_flags&B_ERROR) != 0) { 179 brelse(bp); 180 /* 181 * the inode doesn't contain anything useful, so it would 182 * be misleading to leave it on its hash chain. 183 * 'iput' will take care of putting it back on the free list. 184 */ 185 remque(ip); 186 ip->i_forw = ip; 187 ip->i_back = ip; 188 /* 189 * we also loose its inumber, just in case (as iput 190 * doesn't do that any more) - but as it isn't on its 191 * hash chain, I doubt if this is really necessary .. kre 192 * (probably the two methods are interchangable) 193 */ 194 ip->i_number = 0; 195 #ifdef QUOTA 196 ip->i_dquot = NODQUOT; 197 #endif 198 iput(ip); 199 return(NULL); 200 } 201 dp = bp->b_un.b_dino; 202 dp += itoo(fs, ino); 203 ip->i_ic = dp->di_ic; 204 brelse(bp); 205 #ifdef QUOTA 206 if (ip->i_mode == 0) 207 ip->i_dquot = NODQUOT; 208 else 209 ip->i_dquot = inoquota(ip); 210 #endif 211 return (ip); 212 } 213 214 /* 215 * Decrement reference count of 216 * an inode structure. 217 * On the last reference, 218 * write the inode out and if necessary, 219 * truncate and deallocate the file. 220 */ 221 iput(ip) 222 register struct inode *ip; 223 { 224 225 if ((ip->i_flag & ILOCKED) == 0) 226 panic("iput"); 227 iunlock(ip); 228 irele(ip); 229 } 230 231 irele(ip) 232 register struct inode *ip; 233 { 234 int mode; 235 236 if (ip->i_count == 1) { 237 ip->i_flag |= ILOCKED; 238 if (ip->i_nlink <= 0) { 239 itrunc(ip, (u_long)0); 240 mode = ip->i_mode; 241 ip->i_mode = 0; 242 ip->i_rdev = 0; 243 ip->i_flag |= IUPD|ICHG; 244 ifree(ip, ip->i_number, mode); 245 #ifdef QUOTA 246 (void) chkiq(ip->i_dev, ip, ip->i_uid, 0); 247 dqrele(ip->i_dquot); 248 ip->i_dquot = NODQUOT; 249 #endif 250 } 251 IUPDAT(ip, &time, &time, 0); 252 iunlock(ip); 253 ip->i_flag = 0; 254 /* 255 * Put the inode on the end of the free list. 256 * Possibly in some cases it would be better to 257 * put the inode at the head of the free list, 258 * (eg: where i_mode == 0 || i_number == 0) 259 * but I will think about that later .. kre 260 * (i_number is rarely 0 - only after an i/o error in iget, 261 * where i_mode == 0, the inode will probably be wanted 262 * again soon for an ialloc, so possibly we should keep it) 263 */ 264 if (ifreeh) { 265 *ifreet = ip; 266 ip->i_freeb = ifreet; 267 } else { 268 ifreeh = ip; 269 ip->i_freeb = &ifreeh; 270 } 271 ip->i_freef = NULL; 272 ifreet = &ip->i_freef; 273 } 274 ip->i_count--; 275 } 276 277 /* 278 * Check accessed and update flags on 279 * an inode structure. 280 * If any is on, update the inode 281 * with the current time. 282 * If waitfor is given, then must insure 283 * i/o order so wait for write to complete. 284 */ 285 iupdat(ip, ta, tm, waitfor) 286 register struct inode *ip; 287 struct timeval *ta, *tm; 288 int waitfor; 289 { 290 register struct buf *bp; 291 struct dinode *dp; 292 register struct fs *fp; 293 294 fp = ip->i_fs; 295 if ((ip->i_flag & (IUPD|IACC|ICHG)) != 0) { 296 if (fp->fs_ronly) 297 return; 298 bp = bread(ip->i_dev, fsbtodb(fp, itod(fp, ip->i_number)), 299 (int)fp->fs_bsize); 300 if (bp->b_flags & B_ERROR) { 301 brelse(bp); 302 return; 303 } 304 if (ip->i_flag&IACC) 305 ip->i_atime = ta->tv_sec; 306 if (ip->i_flag&IUPD) 307 ip->i_mtime = tm->tv_sec; 308 if (ip->i_flag&ICHG) 309 ip->i_ctime = time.tv_sec; 310 ip->i_flag &= ~(IUPD|IACC|ICHG); 311 dp = bp->b_un.b_dino + itoo(fp, ip->i_number); 312 dp->di_ic = ip->i_ic; 313 if (waitfor) 314 bwrite(bp); 315 else 316 bdwrite(bp); 317 } 318 } 319 320 #define SINGLE 0 /* index of single indirect block */ 321 #define DOUBLE 1 /* index of double indirect block */ 322 #define TRIPLE 2 /* index of triple indirect block */ 323 /* 324 * Truncate the inode ip to at most 325 * length size. Free affected disk 326 * blocks -- the blocks of the file 327 * are removed in reverse order. 328 * 329 * NB: triple indirect blocks are untested. 330 */ 331 itrunc(oip, length) 332 struct inode *oip; 333 u_long length; 334 { 335 register i; 336 register daddr_t lastblock; 337 daddr_t bn, lastiblock[NIADDR]; 338 register struct fs *fs; 339 register struct inode *ip; 340 struct inode tip; 341 long blocksreleased = 0, nblocks; 342 long indirtrunc(); 343 int level; 344 345 if (oip->i_size <= length) 346 return; 347 /* 348 * Calculate index into inode's block list of 349 * last direct and indirect blocks (if any) 350 * which we want to keep. Lastblock is -1 when 351 * the file is truncated to 0. 352 */ 353 fs = oip->i_fs; 354 lastblock = lblkno(fs, length + fs->fs_bsize - 1) - 1; 355 lastiblock[SINGLE] = lastblock - NDADDR; 356 lastiblock[DOUBLE] = lastiblock[SINGLE] - NINDIR(fs); 357 lastiblock[TRIPLE] = lastiblock[DOUBLE] - NINDIR(fs) * NINDIR(fs); 358 nblocks = btodb(fs->fs_bsize); 359 /* 360 * Update size of file and block pointers 361 * on disk before we start freeing blocks. 362 * If we crash before free'ing blocks below, 363 * the blocks will be returned to the free list. 364 * lastiblock values are also normalized to -1 365 * for calls to indirtrunc below. 366 * (? fsck doesn't check validity of pointers in indirect blocks) 367 */ 368 tip = *oip; 369 for (level = TRIPLE; level >= SINGLE; level--) 370 if (lastiblock[level] < 0) { 371 oip->i_ib[level] = 0; 372 lastiblock[level] = -1; 373 } 374 for (i = NDADDR - 1; i > lastblock; i--) 375 oip->i_db[i] = 0; 376 oip->i_size = length; 377 oip->i_flag |= ICHG|IUPD; 378 iupdat(oip, &time, &time, 1); 379 ip = &tip; 380 381 /* 382 * Indirect blocks first. 383 */ 384 for (level = TRIPLE; level >= SINGLE; level--) { 385 bn = ip->i_ib[level]; 386 if (bn != 0) { 387 blocksreleased += 388 indirtrunc(ip, bn, lastiblock[level], level); 389 if (lastiblock[level] < 0) { 390 ip->i_ib[level] = 0; 391 free(ip, bn, (off_t)fs->fs_bsize); 392 blocksreleased += nblocks; 393 } 394 } 395 if (lastiblock[level] >= 0) 396 goto done; 397 } 398 399 /* 400 * All whole direct blocks or frags. 401 */ 402 for (i = NDADDR - 1; i > lastblock; i--) { 403 register int size; 404 405 bn = ip->i_db[i]; 406 if (bn == 0) 407 continue; 408 ip->i_db[i] = 0; 409 size = (off_t)blksize(fs, ip, i); 410 free(ip, bn, size); 411 blocksreleased += btodb(size); 412 } 413 if (lastblock < 0) 414 goto done; 415 416 /* 417 * Finally, look for a change in size of the 418 * last direct block; release any frags. 419 */ 420 bn = ip->i_db[lastblock]; 421 if (bn != 0) { 422 int oldspace, newspace; 423 424 /* 425 * Calculate amount of space we're giving 426 * back as old block size minus new block size. 427 */ 428 oldspace = blksize(fs, ip, lastblock); 429 ip->i_size = length; 430 newspace = blksize(fs, ip, lastblock); 431 if (newspace == 0) 432 panic("itrunc: newspace"); 433 if (oldspace - newspace > 0) { 434 /* 435 * Block number of space to be free'd is 436 * the old block # plus the number of frags 437 * required for the storage we're keeping. 438 */ 439 bn += numfrags(fs, newspace); 440 free(ip, bn, oldspace - newspace); 441 blocksreleased += btodb(oldspace - newspace); 442 } 443 } 444 done: 445 /* BEGIN PARANOIA */ 446 for (level = SINGLE; level <= TRIPLE; level++) 447 if (ip->i_ib[level] != oip->i_ib[level]) 448 panic("itrunc1"); 449 for (i = 0; i < NDADDR; i++) 450 if (ip->i_db[i] != oip->i_db[i]) 451 panic("itrunc2"); 452 /* END PARANOIA */ 453 oip->i_blocks -= blocksreleased; 454 if (oip->i_blocks < 0) /* sanity */ 455 oip->i_blocks = 0; 456 oip->i_flag |= ICHG; 457 #ifdef QUOTA 458 (void) chkdq(oip, -blocksreleased, 0); 459 #endif 460 } 461 462 /* 463 * Release blocks associated with the inode ip and 464 * stored in the indirect block bn. Blocks are free'd 465 * in LIFO order up to (but not including) lastbn. If 466 * level is greater than SINGLE, the block is an indirect 467 * block and recursive calls to indirtrunc must be used to 468 * cleanse other indirect blocks. 469 * 470 * NB: triple indirect blocks are untested. 471 */ 472 long 473 indirtrunc(ip, bn, lastbn, level) 474 register struct inode *ip; 475 daddr_t bn, lastbn; 476 int level; 477 { 478 register int i; 479 struct buf *bp, *copy; 480 register daddr_t *bap; 481 register struct fs *fs = ip->i_fs; 482 daddr_t nb, last; 483 long factor; 484 int blocksreleased = 0, nblocks; 485 486 /* 487 * Calculate index in current block of last 488 * block to be kept. -1 indicates the entire 489 * block so we need not calculate the index. 490 */ 491 factor = 1; 492 for (i = SINGLE; i < level; i++) 493 factor *= NINDIR(fs); 494 last = lastbn; 495 if (lastbn > 0) 496 last /= factor; 497 nblocks = btodb(fs->fs_bsize); 498 /* 499 * Get buffer of block pointers, zero those 500 * entries corresponding to blocks to be free'd, 501 * and update on disk copy first. 502 */ 503 copy = geteblk((int)fs->fs_bsize); 504 bp = bread(ip->i_dev, fsbtodb(fs, bn), (int)fs->fs_bsize); 505 if (bp->b_flags&B_ERROR) { 506 brelse(copy); 507 brelse(bp); 508 return (0); 509 } 510 bap = bp->b_un.b_daddr; 511 bcopy((caddr_t)bap, (caddr_t)copy->b_un.b_daddr, (u_int)fs->fs_bsize); 512 bzero((caddr_t)&bap[last + 1], 513 (u_int)(NINDIR(fs) - (last + 1)) * sizeof (daddr_t)); 514 bwrite(bp); 515 bp = copy, bap = bp->b_un.b_daddr; 516 517 /* 518 * Recursively free totally unused blocks. 519 */ 520 for (i = NINDIR(fs) - 1; i > last; i--) { 521 nb = bap[i]; 522 if (nb == 0) 523 continue; 524 if (level > SINGLE) 525 blocksreleased += 526 indirtrunc(ip, nb, (daddr_t)-1, level - 1); 527 free(ip, nb, (int)fs->fs_bsize); 528 blocksreleased += nblocks; 529 } 530 531 /* 532 * Recursively free last partial block. 533 */ 534 if (level > SINGLE && lastbn >= 0) { 535 last = lastbn % factor; 536 nb = bap[i]; 537 if (nb != 0) 538 blocksreleased += indirtrunc(ip, nb, last, level - 1); 539 } 540 brelse(bp); 541 return (blocksreleased); 542 } 543 544 /* 545 * remove any inodes in the inode cache belonging to dev 546 * 547 * There should not be any active ones, return error if any are found 548 * (nb: this is a user error, not a system err) 549 * 550 * Also, count the references to dev by block devices - this really 551 * has nothing to do with the object of the procedure, but as we have 552 * to scan the inode table here anyway, we might as well get the 553 * extra benefit. 554 * 555 * this is called from sumount()/sys3.c when dev is being unmounted 556 */ 557 #ifdef QUOTA 558 iflush(dev, iq) 559 dev_t dev; 560 struct inode *iq; 561 #else 562 iflush(dev) 563 dev_t dev; 564 #endif 565 { 566 register struct inode *ip; 567 register open = 0; 568 569 for (ip = inode; ip < inodeNINODE; ip++) { 570 #ifdef QUOTA 571 if (ip != iq && ip->i_dev == dev) 572 #else 573 if (ip->i_dev == dev) 574 #endif 575 if (ip->i_count) 576 return(-1); 577 else { 578 remque(ip); 579 ip->i_forw = ip; 580 ip->i_back = ip; 581 /* 582 * as i_count == 0, the inode was on the free 583 * list already, just leave it there, it will 584 * fall off the bottom eventually. We could 585 * perhaps move it to the head of the free 586 * list, but as umounts are done so 587 * infrequently, we would gain very little, 588 * while making the code bigger. 589 */ 590 #ifdef QUOTA 591 dqrele(ip->i_dquot); 592 ip->i_dquot = NODQUOT; 593 #endif 594 } 595 else if (ip->i_count && (ip->i_mode&IFMT)==IFBLK && 596 ip->i_rdev == dev) 597 open++; 598 } 599 return (open); 600 } 601 602 /* 603 * Lock an inode. If its already locked, set the WANT bit and sleep. 604 */ 605 ilock(ip) 606 register struct inode *ip; 607 { 608 609 ILOCK(ip); 610 } 611 612 /* 613 * Unlock an inode. If WANT bit is on, wakeup. 614 */ 615 iunlock(ip) 616 register struct inode *ip; 617 { 618 619 IUNLOCK(ip); 620 } 621