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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 | /* * fs/inode.c * * Complete reimplementation * (C) 1997 Thomas Schoebel-Theuer */ /* Everything here is intended to be MP-safe. However, other parts * of the kernel are not yet MP-safe, in particular the inode->i_count++ * that are spread over everywhere. These should be replaced by * iinc() as soon as possible. Since I have no MP machine, I could * not test it. */ #include <linux/config.h> #include <linux/errno.h> #include <linux/fs.h> #include <linux/string.h> #include <linux/mm.h> #include <linux/kernel.h> #include <linux/dlists.h> #include <linux/dalloc.h> #include <linux/omirr.h> /* #define DEBUG */ #define HASH_SIZE 1024 /* must be a power of 2 */ #define NR_LEVELS 4 #define ST_AGED 1 #define ST_HASHED 2 #define ST_EMPTY 4 #define ST_TO_READ 8 #define ST_TO_WRITE 16 #define ST_TO_PUT 32 #define ST_TO_DROP 64 #define ST_IO (ST_TO_READ|ST_TO_WRITE|ST_TO_PUT|ST_TO_DROP) #define ST_WAITING 128 #define ST_FREEING 256 #define ST_IBASKET 512 /* The idea is to keep empty inodes in a separate list, so no search * is required as long as empty inodes exit. * All reusable inodes occurring in the hash table with i_count==0 * are also registered in the ringlist aged_i[level], but in LRU order. * Used inodes with i_count>0 are kept solely in the hashtable and in * all_i, but in no other list. * The level is used for multilevel aging to avoid thrashing; each * time i_count decreases to 0, the inode is inserted into the next level * ringlist. Cache reusage is simply by taking the _last_ element from the * lowest-level ringlist that contains inodes. * In contrast to the old code, there isn't any O(n) search overhead now * in iget/iput (if you make HASH_SIZE large enough). */ static struct inode * hashtable[HASH_SIZE];/* linked with i_hash_{next,prev} */ static struct inode * all_i = NULL; /* linked with i_{next,prev} */ static struct inode * empty_i = NULL; /* linked with i_{next,prev} */ static struct inode * aged_i[NR_LEVELS+1]; /* linked with i_lru_{next,prev} */ static int aged_reused[NR_LEVELS+1]; /* # removals from aged_i[level] */ static int age_table[NR_LEVELS+1] = { /* You may tune this. */ 1, 4, 10, 100, 1000 }; /* after which # of uses to increase to the next level */ /* This is for kernel/sysctl.c */ /* Just aligning plain ints and arrays thereof doesn't work reliably.. */ struct { int nr_inodes; int nr_free_inodes; int aged_count[NR_LEVELS+1]; /* # in each level */ } inodes_stat; int max_inodes = NR_INODE; unsigned long last_inode = 0; void inode_init(void) { memset(hashtable, 0, sizeof(hashtable)); memset(aged_i, 0, sizeof(aged_i)); memset(aged_reused, 0, sizeof(aged_reused)); memset(&inodes_stat, 0, sizeof(inodes_stat)); } /* Intended for short locks of the above global data structures. * Could be replaced with spinlocks completely, since there is * no blocking during manipulation of the static data; however the * lock in invalidate_inodes() may last relatively long. */ #ifdef __SMP__ struct semaphore vfs_sem = MUTEX; #endif DEF_INSERT(all,struct inode,i_next,i_prev) DEF_REMOVE(all,struct inode,i_next,i_prev) DEF_INSERT(lru,struct inode,i_lru_next,i_lru_prev) DEF_REMOVE(lru,struct inode,i_lru_next,i_lru_prev) DEF_INSERT(hash,struct inode,i_hash_next,i_hash_prev) DEF_REMOVE(hash,struct inode,i_hash_next,i_hash_prev) DEF_INSERT(ibasket,struct inode,i_basket_next,i_basket_prev) DEF_REMOVE(ibasket,struct inode,i_basket_next,i_basket_prev) #ifdef DEBUG extern void printpath(struct dentry * entry); struct inode * xtst[15000]; int xcnt = 0; void xcheck(char * txt, struct inode * p) { int i; for(i=xcnt-1; i>=0; i--) if(xtst[i] == p) return; printk("Bogus inode %p in %s\n", p, txt); } #else #define xcheck(t,p) /*nothing*/ #endif static inline struct inode * grow_inodes(void) { struct inode * res; struct inode * inode = res = (struct inode*)__get_free_page(GFP_KERNEL); int size = PAGE_SIZE; if(!inode) return NULL; size -= sizeof(struct inode); inode++; inodes_stat.nr_inodes++; #ifdef DEBUG xtst[xcnt++]=res; #endif while(size >= sizeof(struct inode)) { #ifdef DEBUG xtst[xcnt++]=inode; #endif inodes_stat.nr_inodes++; inodes_stat.nr_free_inodes++; insert_all(&empty_i, inode); inode->i_status = ST_EMPTY; inode++; size -= sizeof(struct inode); } return res; } static inline int hash(dev_t i_dev, unsigned long i_ino) { return ((int)i_ino ^ ((int)i_dev << 6)) & (HASH_SIZE-1); } static inline blocking void wait_io(struct inode * inode, unsigned short flags) { while(inode->i_status & flags) { struct wait_queue wait = {current, NULL}; inode->i_status |= ST_WAITING; vfs_unlock(); add_wait_queue(&inode->i_wait, &wait); sleep_on(&inode->i_wait); remove_wait_queue(&inode->i_wait, &wait); vfs_lock(); } } static inline blocking void set_io(struct inode * inode, unsigned short waitflags, unsigned short setflags) { wait_io(inode, waitflags); inode->i_status |= setflags; vfs_unlock(); } static inline blocking int release_io(struct inode * inode, unsigned short flags) { int res = 0; vfs_lock(); inode->i_status &= ~flags; if(inode->i_status & ST_WAITING) { inode->i_status &= ~ST_WAITING; vfs_unlock(); wake_up(&inode->i_wait); res = 1; } return res; } static inline blocking void _io(void (*op)(struct inode*), struct inode * inode, unsigned short waitflags, unsigned short setflags) { /* Do nothing if the same op is already in progress. */ if(op && !(inode->i_status & setflags)) { set_io(inode, waitflags, setflags); op(inode); if(release_io(inode, setflags)) { /* Somebody grabbed my inode from under me. */ #ifdef DEBUG printk("_io grab!\n"); #endif vfs_lock(); } } } blocking int _free_ibasket(struct super_block * sb) { if(sb->s_ibasket) { struct inode * delinquish = sb->s_ibasket->i_basket_prev; #if 0 printpath(delinquish->i_dentry); printk(" delinquish\n"); #endif _clear_inode(delinquish, 0, 1); return 1; } return 0; } static /*inline*/ void _put_ibasket(struct inode * inode) { struct super_block * sb = inode->i_sb; if(!(inode->i_status & ST_IBASKET)) { inode->i_status |= ST_IBASKET; insert_ibasket(&sb->s_ibasket, inode); sb->s_ibasket_count++; if(sb->s_ibasket_count > sb->s_ibasket_max) (void)_free_ibasket(sb); } } blocking void _clear_inode(struct inode * inode, int external, int verbose) { xcheck("_clear_inode",inode); if(inode->i_status & ST_IBASKET) { struct super_block * sb = inode->i_sb; remove_ibasket(&sb->s_ibasket, inode); sb->s_ibasket_count--; inode->i_status &= ~ST_IBASKET; #if 0 printpath(inode->i_dentry); printk(" put_inode\n"); #endif _io(sb->s_op->put_inode, inode, ST_TO_PUT|ST_TO_WRITE, ST_TO_PUT); if(inode->i_status & ST_EMPTY) return; } if(inode->i_status & ST_HASHED) remove_hash(&hashtable[hash(inode->i_dev, inode->i_ino)], inode); if(inode->i_status & ST_AGED) { /* "cannot happen" when called from an fs because at least * the caller must use it. Can happen when called from * invalidate_inodes(). */ if(verbose) printk("VFS: clearing aged inode\n"); if(atomic_read(&inode->i_count)) printk("VFS: aged inode is in use\n"); remove_lru(&aged_i[inode->i_level], inode); inodes_stat.aged_count[inode->i_level]--; } if(!external && inode->i_status & ST_IO) { printk("VFS: clearing inode during IO operation\n"); } if(!(inode->i_status & ST_EMPTY)) { remove_all(&all_i, inode); inode->i_status = ST_EMPTY; while(inode->i_dentry) { d_del(inode->i_dentry, D_NO_CLEAR_INODE); } if(inode->i_pages) { vfs_unlock(); /* may block, can that be revised? */ truncate_inode_pages(inode, 0); vfs_lock(); } insert_all(&empty_i, inode); inodes_stat.nr_free_inodes++; } else if(external) printk("VFS: empty inode is unnecessarily cleared multiple " "times by an fs\n"); else printk("VFS: clearing empty inode\n"); inode->i_status = ST_EMPTY; /* The inode is not really cleared any more here, but only once * when taken from empty_i. This saves instructions and processor * cache pollution. */ } void insert_inode_hash(struct inode * inode) { xcheck("insert_inode_hash",inode); vfs_lock(); if(!(inode->i_status & ST_HASHED)) { insert_hash(&hashtable[hash(inode->i_dev, inode->i_ino)], inode); inode->i_status |= ST_HASHED; } else printk("VFS: trying to hash an inode again\n"); vfs_unlock(); } blocking struct inode * _get_empty_inode(void) { struct inode * inode; int retry = 0; retry: inode = empty_i; if(inode) { remove_all(&empty_i, inode); inodes_stat.nr_free_inodes--; } else if(inodes_stat.nr_inodes < max_inodes || retry > 2) { inode = grow_inodes(); } if(!inode) { int level; int usable = 0; for(level = 0; level <= NR_LEVELS; level++) if(aged_i[level]) { inode = aged_i[level]->i_lru_prev; /* Here is the picking strategy, tune this */ if(aged_reused[level] < (usable++ ? inodes_stat.aged_count[level] : 2)) break; aged_reused[level] = 0; } if(inode) { if(!(inode->i_status & ST_AGED)) printk("VFS: inode aging inconsistency\n"); if(atomic_read(&inode->i_count) + inode->i_ddir_count) printk("VFS: i_count of aged inode is not zero\n"); if(inode->i_dirt) printk("VFS: Hey, somebody made my aged inode dirty\n"); _clear_inode(inode, 0, 0); goto retry; } } if(!inode) { vfs_unlock(); schedule(); if(retry > 10) panic("VFS: cannot repair inode shortage"); if(retry > 2) printk("VFS: no free inodes\n"); retry++; vfs_lock(); goto retry; } xcheck("get_empty_inode",inode); memset(inode, 0, sizeof(struct inode)); atomic_set(&inode->i_count, 1); inode->i_nlink = 1; sema_init(&inode->i_sem, 1); inode->i_ino = ++last_inode; inode->i_version = ++event; insert_all(&all_i, inode); return inode; } static inline blocking struct inode * _get_empty_inode_hashed(dev_t i_dev, unsigned long i_ino) { struct inode ** base = &hashtable[hash(i_dev, i_ino)]; struct inode * inode = *base; if(inode) do { if(inode->i_ino == i_ino && inode->i_dev == i_dev) { atomic_inc(&inode->i_count); printk("VFS: inode %lx is already in use\n", i_ino); return inode; } inode = inode->i_hash_next; } while(inode != *base); inode = _get_empty_inode(); inode->i_dev = i_dev; inode->i_ino = i_ino; insert_hash(base, inode); inode->i_status |= ST_HASHED; return inode; } blocking struct inode * get_empty_inode_hashed(dev_t i_dev, unsigned long i_ino) { struct inode * inode; vfs_lock(); inode = _get_empty_inode_hashed(i_dev, i_ino); vfs_unlock(); return inode; } void _get_inode(struct inode * inode) { if(inode->i_status & ST_IBASKET) { inode->i_status &= ~ST_IBASKET; remove_ibasket(&inode->i_sb->s_ibasket, inode); inode->i_sb->s_ibasket_count--; } if(inode->i_status & ST_AGED) { inode->i_status &= ~ST_AGED; remove_lru(&aged_i[inode->i_level], inode); inodes_stat.aged_count[inode->i_level]--; aged_reused[inode->i_level]++; if(S_ISDIR(inode->i_mode)) /* make dirs less thrashable */ inode->i_level = NR_LEVELS-1; else if(inode->i_nlink > 1) /* keep hardlinks totally separate */ inode->i_level = NR_LEVELS; else if(++inode->i_reuse_count >= age_table[inode->i_level] && inode->i_level < NR_LEVELS-1) inode->i_level++; if(atomic_read(&inode->i_count) != 1) printk("VFS: inode count was not zero\n"); } else if(inode->i_status & ST_EMPTY) printk("VFS: invalid reuse of empty inode\n"); } blocking struct inode * __iget(struct super_block * sb, unsigned long i_ino, int crossmntp) { struct inode ** base; struct inode * inode; dev_t i_dev; if(!sb) panic("VFS: iget with sb == NULL"); i_dev = sb->s_dev; if(!i_dev) panic("VFS: sb->s_dev is NULL\n"); base = &hashtable[hash(i_dev, i_ino)]; vfs_lock(); inode = *base; if(inode) do { if(inode->i_ino == i_ino && inode->i_dev == i_dev) { atomic_inc(&inode->i_count); _get_inode(inode); /* Allow concurrent writes/puts. This is in particular * useful e.g. when syncing large chunks. * I hope the i_dirty flag is everywhere set as soon * as _any_ modifcation is made and _before_ * giving up control, so no harm should occur if data * is modified during writes, because it will be * rewritten again (does a short inconsistency on the * disk harm?) */ wait_io(inode, ST_TO_READ); vfs_unlock(); goto done; } inode = inode->i_hash_next; } while(inode != *base); inode = _get_empty_inode_hashed(i_dev, i_ino); inode->i_sb = sb; inode->i_flags = sb->s_flags; if(sb->s_op && sb->s_op->read_inode) { set_io(inode, 0, ST_TO_READ); /* do not wait at all */ sb->s_op->read_inode(inode); if(release_io(inode, ST_TO_READ)) goto done; } vfs_unlock(); done: while(crossmntp && inode->i_mount) { struct inode * tmp = inode->i_mount; iinc(tmp); iput(inode); inode = tmp; } xcheck("_iget",inode); return inode; } blocking void __iput(struct inode * inode) { struct super_block * sb; xcheck("_iput",inode); if(atomic_read(&inode->i_count) + inode->i_ddir_count < 0) printk("VFS: i_count is negative\n"); if((atomic_read(&inode->i_count) + inode->i_ddir_count) || (inode->i_status & ST_FREEING)) { return; } inode->i_status |= ST_FREEING; #ifdef CONFIG_OMIRR if(inode->i_status & ST_MODIFIED) { inode->i_status &= ~ST_MODIFIED; omirr_printall(inode, " W %ld ", CURRENT_TIME); } #endif if(inode->i_pipe) { free_page((unsigned long)PIPE_BASE(*inode)); PIPE_BASE(*inode)= NULL; } if((sb = inode->i_sb)) { if(sb->s_type && (sb->s_type->fs_flags & FS_NO_DCACHE)) { while(inode->i_dentry) d_del(inode->i_dentry, D_NO_CLEAR_INODE); if(atomic_read(&inode->i_count) + inode->i_ddir_count) goto done; } if(sb->s_op) { if(inode->i_nlink <= 0 && inode->i_dent_count && !(inode->i_status & (ST_EMPTY|ST_IBASKET)) && (sb->s_type->fs_flags & FS_IBASKET)) { _put_ibasket(inode); goto done; } if(!inode->i_dent_count || (sb->s_type->fs_flags & FS_NO_DCACHE)) { _io(sb->s_op->put_inode, inode, ST_TO_PUT|ST_TO_WRITE, ST_TO_PUT); if(atomic_read(&inode->i_count) + inode->i_ddir_count) goto done; if(inode->i_nlink <= 0) { if(!(inode->i_status & ST_EMPTY)) { _clear_inode(inode, 0, 1); } goto done; } } if(inode->i_dirt) { inode->i_dirt = 0; _io(sb->s_op->write_inode, inode, ST_TO_PUT|ST_TO_WRITE, ST_TO_WRITE); if(atomic_read(&inode->i_count) + inode->i_ddir_count) goto done; } } if(IS_WRITABLE(inode) && sb->dq_op) { /* can operate in parallel to other ops ? */ _io(sb->dq_op->drop, inode, 0, ST_TO_DROP); if(atomic_read(&inode->i_count) + inode->i_ddir_count) goto done; } } if(inode->i_mmap) printk("VFS: inode has mappings\n"); if(inode->i_status & ST_AGED) { printk("VFS: reaging inode\n"); #if defined(DEBUG) printpath(inode->i_dentry); printk("\n"); #endif goto done; } if(!(inode->i_status & (ST_HASHED|ST_EMPTY))) { _clear_inode(inode, 0, 1); goto done; } if(inode->i_status & ST_EMPTY) { printk("VFS: aging an empty inode\n"); goto done; } insert_lru(&aged_i[inode->i_level], inode); inodes_stat.aged_count[inode->i_level]++; inode->i_status |= ST_AGED; done: inode->i_status &= ~ST_FREEING; } blocking void _iput(struct inode * inode) { vfs_lock(); __iput(inode); vfs_unlock(); } blocking void sync_inodes(kdev_t dev) { struct inode * inode; vfs_lock(); inode = all_i; if(inode) do { xcheck("sync_inodes",inode); if(inode->i_dirt && (inode->i_dev == dev || !dev)) { if(inode->i_sb && inode->i_sb->s_op && !(inode->i_status & ST_FREEING)) { inode->i_dirt = 0; _io(inode->i_sb->s_op->write_inode, inode, ST_IO, ST_TO_WRITE); } } inode = inode->i_next; } while(inode != all_i); vfs_unlock(); } blocking int _check_inodes(kdev_t dev, int complain) { struct inode * inode; int bad = 0; vfs_lock(); startover: inode = all_i; if(inode) do { struct inode * next; xcheck("_check_inodes",inode); next = inode->i_next; if(inode->i_dev == dev) { if(inode->i_dirt || atomic_read(&inode->i_count)) { bad++; } else { _clear_inode(inode, 0, 0); /* _clear_inode() may recursively clear other * inodes, probably also the next one. */ if(next->i_status & ST_EMPTY) goto startover; } } inode = next; } while(inode != all_i); vfs_unlock(); if(complain && bad) printk("VFS: %d inode(s) busy on removed device `%s'\n", bad, kdevname(dev)); return (bad == 0); } /*inline*/ void invalidate_inodes(kdev_t dev) { /* Requires two passes, because of the new dcache holding * directories with i_count > 1. */ (void)_check_inodes(dev, 0); (void)_check_inodes(dev, 1); } /*inline*/ int fs_may_mount(kdev_t dev) { return _check_inodes(dev, 0); } int fs_may_remount_ro(kdev_t dev) { (void)dev; return 1; /* not checked any more */ } int fs_may_umount(kdev_t dev, struct inode * mount_root) { struct inode * inode; vfs_lock(); inode = all_i; if(inode) do { xcheck("fs_may_umount",inode); if(inode->i_dev == dev && atomic_read(&inode->i_count)) if(inode != mount_root || atomic_read(&inode->i_count) > (inode->i_mount == inode ? 2 : 1)) { vfs_unlock(); return 0; } inode = inode->i_next; } while(inode != all_i); vfs_unlock(); return 1; } extern struct inode_operations pipe_inode_operations; blocking struct inode * get_pipe_inode(void) { struct inode * inode = get_empty_inode(); PIPE_BASE(*inode) = (char*)__get_free_page(GFP_USER); if(!(PIPE_BASE(*inode))) { iput(inode); return NULL; } inode->i_blksize = PAGE_SIZE; inode->i_pipe = 1; inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR; atomic_inc(&inode->i_count); inode->i_uid = current->fsuid; inode->i_gid = current->fsgid; inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; inode->i_op = &pipe_inode_operations; PIPE_READERS(*inode) = PIPE_WRITERS(*inode) = 1; /* I hope this does not introduce security problems. * Please check and give me response. */ { char dummyname[32]; struct qstr dummy = { dummyname, 0 }; struct dentry * new; sprintf(dummyname, ".anonymous-pipe-%06lud", inode->i_ino); dummy.len = strlen(dummyname); vfs_lock(); new = d_alloc(the_root, dummy.len, 0); if(new) d_add(new, inode, &dummy, D_BASKET); vfs_unlock(); } return inode; } int bmap(struct inode * inode, int block) { if (inode->i_op && inode->i_op->bmap) return inode->i_op->bmap(inode, block); return 0; } |