ufs_dirhash.c revision 82364
1/* 2 * Copyright (c) 2001 Ian Dowse. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 * 25 * $FreeBSD: head/sys/ufs/ufs/ufs_dirhash.c 82364 2001-08-26 20:47:19Z iedowse $ 26 */ 27/* 28 * This implements a hash-based lookup scheme for UFS directories. 29 */ 30 31#include "opt_ufs.h" 32 33#ifdef UFS_DIRHASH 34 35#include <sys/param.h> 36#include <sys/systm.h> 37#include <sys/kernel.h> 38#include <sys/mutex.h> 39#include <sys/malloc.h> 40#include <sys/fnv_hash.h> 41#include <sys/proc.h> 42#include <sys/bio.h> 43#include <sys/buf.h> 44#include <sys/vnode.h> 45#include <sys/mount.h> 46#include <sys/sysctl.h> 47#include <vm/vm_zone.h> 48 49#include <ufs/ufs/quota.h> 50#include <ufs/ufs/inode.h> 51#include <ufs/ufs/dir.h> 52#include <ufs/ufs/dirhash.h> 53#include <ufs/ufs/extattr.h> 54#include <ufs/ufs/ufsmount.h> 55#include <ufs/ufs/ufs_extern.h> 56 57#define WRAPINCR(val, limit) (((val) + 1 == (limit)) ? 0 : ((val) + 1)) 58#define OFSFMT(vp) ((vp)->v_mount->mnt_maxsymlinklen <= 0) 59 60static MALLOC_DEFINE(M_DIRHASH, "UFS dirhash", "UFS directory hash tables"); 61 62SYSCTL_NODE(_vfs, OID_AUTO, ufs, CTLFLAG_RD, 0, "UFS filesystem"); 63 64static int ufs_mindirhashsize = DIRBLKSIZ * 5; 65SYSCTL_INT(_vfs_ufs, OID_AUTO, dirhash_minsize, CTLFLAG_RW, 66 &ufs_mindirhashsize, 67 0, "minimum directory size in bytes for which to use hashed lookup"); 68static int ufs_dirhashmaxmem = 2 * 1024 * 1024; 69SYSCTL_INT(_vfs_ufs, OID_AUTO, dirhash_maxmem, CTLFLAG_RW, &ufs_dirhashmaxmem, 70 0, "maximum allowed dirhash memory usage"); 71static int ufs_dirhashmem; 72SYSCTL_INT(_vfs_ufs, OID_AUTO, dirhash_mem, CTLFLAG_RD, &ufs_dirhashmem, 73 0, "current dirhash memory usage"); 74static int ufs_dirhashcheck = 1; 75SYSCTL_INT(_vfs_ufs, OID_AUTO, dirhash_docheck, CTLFLAG_RW, &ufs_dirhashcheck, 76 0, "enable extra sanity tests"); 77 78 79static int ufsdirhash_hash(struct dirhash *dh, char *name, int namelen); 80static void ufsdirhash_adjfree(struct dirhash *dh, doff_t offset, int diff); 81static void ufsdirhash_delslot(struct dirhash *dh, int slot); 82static int ufsdirhash_findslot(struct dirhash *dh, char *name, int namelen, 83 doff_t offset); 84static doff_t ufsdirhash_getprev(struct direct *dp, doff_t offset); 85static void ufsdirhash_init(void); 86static int ufsdirhash_recycle(int wanted); 87 88static vm_zone_t ufsdirhash_zone; 89 90/* Dirhash list; recently-used entries are near the tail. */ 91static TAILQ_HEAD(, dirhash) ufsdirhash_list; 92 93/* Protects: ufsdirhash_list, `dh_list' field, ufs_dirhashmem. */ 94static struct mtx ufsdirhash_mtx; 95 96/* 97 * Locking order: 98 * ufsdirhash_mtx 99 * dh_mtx 100 * 101 * The dh_mtx mutex should be aquired either via the inode lock, or via 102 * ufsdirhash_mtx. Only the owner of the inode may free the associated 103 * dirhash, but anything can steal its memory and set dh_hash to NULL. 104 */ 105 106/* 107 * Attempt to build up a hash table for the directory contents in 108 * inode 'ip'. Returns 0 on success, or -1 of the operation failed. 109 */ 110int 111ufsdirhash_build(struct inode *ip) 112{ 113 struct dirhash *dh; 114 struct buf *bp = NULL; 115 struct direct *ep; 116 struct vnode *vp; 117 doff_t bmask, pos; 118 int dirblocks, i, j, memreqd, nblocks, narrays, nslots, slot; 119 120 /* Check if we can/should use dirhash. */ 121 if (ip->i_dirhash == NULL) { 122 if (ip->i_size < ufs_mindirhashsize || OFSFMT(ip->i_vnode)) 123 return (-1); 124 } else { 125 /* Hash exists, but sysctls could have changed. */ 126 if (ip->i_size < ufs_mindirhashsize || 127 ufs_dirhashmem > ufs_dirhashmaxmem) { 128 ufsdirhash_free(ip); 129 return (-1); 130 } 131 /* Check if hash exists and is intact (note: unlocked read). */ 132 if (ip->i_dirhash->dh_hash != NULL) 133 return (0); 134 /* Free the old, recycled hash and build a new one. */ 135 ufsdirhash_free(ip); 136 } 137 138 /* Don't hash removed directories. */ 139 if (ip->i_effnlink == 0) 140 return (-1); 141 142 vp = ip->i_vnode; 143 /* Allocate 50% more entries than this dir size could ever need. */ 144 KASSERT(ip->i_size >= DIRBLKSIZ, ("ufsdirhash_build size")); 145 nslots = ip->i_size / DIRECTSIZ(1); 146 nslots = (nslots * 3 + 1) / 2; 147 narrays = howmany(nslots, DH_NBLKOFF); 148 nslots = narrays * DH_NBLKOFF; 149 dirblocks = howmany(ip->i_size, DIRBLKSIZ); 150 nblocks = (dirblocks * 3 + 1) / 2; 151 152 memreqd = sizeof(*dh) + narrays * sizeof(*dh->dh_hash) + 153 narrays * DH_NBLKOFF * sizeof(**dh->dh_hash) + 154 nblocks * sizeof(*dh->dh_blkfree); 155 mtx_lock(&ufsdirhash_mtx); 156 if (memreqd + ufs_dirhashmem > ufs_dirhashmaxmem) { 157 mtx_unlock(&ufsdirhash_mtx); 158 if (memreqd > ufs_dirhashmaxmem / 2) 159 return (-1); 160 161 /* Try to free some space. */ 162 if (ufsdirhash_recycle(memreqd) != 0) 163 return (-1); 164 /* Enough was freed, and ufsdirhash_mtx has been locked. */ 165 } 166 ufs_dirhashmem += memreqd; 167 mtx_unlock(&ufsdirhash_mtx); 168 169 /* 170 * Use non-blocking mallocs so that we will revert to a linear 171 * lookup on failure rather than potentially blocking forever. 172 */ 173 MALLOC(dh, struct dirhash *, sizeof *dh, M_DIRHASH, M_NOWAIT | M_ZERO); 174 if (dh == NULL) 175 return (-1); 176 MALLOC(dh->dh_hash, doff_t **, narrays * sizeof(dh->dh_hash[0]), 177 M_DIRHASH, M_NOWAIT | M_ZERO); 178 MALLOC(dh->dh_blkfree, u_int8_t *, nblocks * sizeof(dh->dh_blkfree[0]), 179 M_DIRHASH, M_NOWAIT); 180 if (dh->dh_hash == NULL || dh->dh_blkfree == NULL) 181 goto fail; 182 for (i = 0; i < narrays; i++) { 183 if ((dh->dh_hash[i] = zalloc(ufsdirhash_zone)) == NULL) 184 goto fail; 185 for (j = 0; j < DH_NBLKOFF; j++) 186 dh->dh_hash[i][j] = DIRHASH_EMPTY; 187 } 188 189 /* Initialise the hash table and block statistics. */ 190 mtx_init(&dh->dh_mtx, "dirhash", MTX_DEF); 191 dh->dh_narrays = narrays; 192 dh->dh_hlen = nslots; 193 dh->dh_nblk = nblocks; 194 dh->dh_dirblks = dirblocks; 195 for (i = 0; i < dirblocks; i++) 196 dh->dh_blkfree[i] = DIRBLKSIZ / DIRALIGN; 197 for (i = 0; i < DH_NFSTATS; i++) 198 dh->dh_firstfree[i] = -1; 199 dh->dh_firstfree[DH_NFSTATS] = 0; 200 dh->dh_seqopt = 0; 201 dh->dh_seqoff = 0; 202 dh->dh_score = DH_SCOREINIT; 203 ip->i_dirhash = dh; 204 205 bmask = VFSTOUFS(vp->v_mount)->um_mountp->mnt_stat.f_iosize - 1; 206 pos = 0; 207 while (pos < ip->i_size) { 208 /* If necessary, get the next directory block. */ 209 if ((pos & bmask) == 0) { 210 if (bp != NULL) 211 brelse(bp); 212 if (UFS_BLKATOFF(vp, (off_t)pos, NULL, &bp) != 0) 213 goto fail; 214 } 215 216 /* Add this entry to the hash. */ 217 ep = (struct direct *)((char *)bp->b_data + (pos & bmask)); 218 if (ep->d_reclen == 0 || ep->d_reclen > 219 DIRBLKSIZ - (pos & (DIRBLKSIZ - 1))) { 220 /* Corrupted directory. */ 221 brelse(bp); 222 goto fail; 223 } 224 if (ep->d_ino != 0) { 225 /* Add the entry (simplified ufsdirhash_add). */ 226 slot = ufsdirhash_hash(dh, ep->d_name, ep->d_namlen); 227 while (DH_ENTRY(dh, slot) != DIRHASH_EMPTY) 228 slot = WRAPINCR(slot, dh->dh_hlen); 229 dh->dh_hused++; 230 DH_ENTRY(dh, slot) = pos; 231 ufsdirhash_adjfree(dh, pos, -DIRSIZ(0, ep)); 232 } 233 pos += ep->d_reclen; 234 } 235 236 if (bp != NULL) 237 brelse(bp); 238 mtx_lock(&ufsdirhash_mtx); 239 TAILQ_INSERT_TAIL(&ufsdirhash_list, dh, dh_list); 240 dh->dh_onlist = 1; 241 mtx_unlock(&ufsdirhash_mtx); 242 return (0); 243 244fail: 245 if (dh->dh_hash != NULL) { 246 for (i = 0; i < narrays; i++) 247 if (dh->dh_hash[i] != NULL) 248 zfree(ufsdirhash_zone, dh->dh_hash[i]); 249 FREE(dh->dh_hash, M_DIRHASH); 250 } 251 if (dh->dh_blkfree != NULL) 252 FREE(dh->dh_blkfree, M_DIRHASH); 253 FREE(dh, M_DIRHASH); 254 ip->i_dirhash = NULL; 255 mtx_lock(&ufsdirhash_mtx); 256 ufs_dirhashmem -= memreqd; 257 mtx_unlock(&ufsdirhash_mtx); 258 return (-1); 259} 260 261/* 262 * Free any hash table associated with inode 'ip'. 263 */ 264void 265ufsdirhash_free(struct inode *ip) 266{ 267 struct dirhash *dh; 268 int i, mem; 269 270 if ((dh = ip->i_dirhash) == NULL) 271 return; 272 mtx_lock(&ufsdirhash_mtx); 273 mtx_lock(&dh->dh_mtx); 274 if (dh->dh_onlist) 275 TAILQ_REMOVE(&ufsdirhash_list, dh, dh_list); 276 mtx_unlock(&dh->dh_mtx); 277 mtx_unlock(&ufsdirhash_mtx); 278 279 /* The dirhash pointed to by 'dh' is exclusively ours now. */ 280 281 mem = sizeof(*dh); 282 if (dh->dh_hash != NULL) { 283 for (i = 0; i < dh->dh_narrays; i++) 284 zfree(ufsdirhash_zone, dh->dh_hash[i]); 285 FREE(dh->dh_hash, M_DIRHASH); 286 FREE(dh->dh_blkfree, M_DIRHASH); 287 mem += dh->dh_narrays * sizeof(*dh->dh_hash) + 288 dh->dh_narrays * DH_NBLKOFF * sizeof(**dh->dh_hash) + 289 dh->dh_nblk * sizeof(*dh->dh_blkfree); 290 } 291 mtx_destroy(&dh->dh_mtx); 292 FREE(dh, M_DIRHASH); 293 ip->i_dirhash = NULL; 294 295 mtx_lock(&ufsdirhash_mtx); 296 ufs_dirhashmem -= mem; 297 mtx_unlock(&ufsdirhash_mtx); 298} 299 300/* 301 * Find the offset of the specified name within the given inode. 302 * Returns 0 on success, ENOENT if the entry does not exist, or 303 * EJUSTRETURN if the caller should revert to a linear search. 304 * 305 * If successful, the directory offset is stored in *offp, and a 306 * pointer to a struct buf containing the entry is stored in *bpp. If 307 * prevoffp is non-NULL, the offset of the previous entry within 308 * the DIRBLKSIZ-sized block is stored in *prevoffp (if the entry 309 * is the first in a block, the start of the block is used). 310 */ 311int 312ufsdirhash_lookup(struct inode *ip, char *name, int namelen, doff_t *offp, 313 struct buf **bpp, doff_t *prevoffp) 314{ 315 struct dirhash *dh, *dh_next; 316 struct direct *dp; 317 struct vnode *vp; 318 struct buf *bp; 319 doff_t blkoff, bmask, offset, prevoff; 320 int i, slot; 321 322 if ((dh = ip->i_dirhash) == NULL) 323 return (EJUSTRETURN); 324 /* 325 * Move this dirhash towards the end of the list if it has a 326 * score higher than the next entry, and aquire the dh_mtx. 327 * Optimise the case where it's already the last by performing 328 * an unlocked read of the TAILQ_NEXT pointer. 329 * 330 * In both cases, end up holding just dh_mtx. 331 */ 332 if (TAILQ_NEXT(dh, dh_list) != NULL) { 333 mtx_lock(&ufsdirhash_mtx); 334 mtx_lock(&dh->dh_mtx); 335 /* 336 * If the new score will be greater than that of the next 337 * entry, then move this entry past it. With both mutexes 338 * held, dh_next won't go away, but its dh_score could 339 * change; that's not important since it is just a hint. 340 */ 341 if (dh->dh_hash != NULL && 342 (dh_next = TAILQ_NEXT(dh, dh_list)) != NULL && 343 dh->dh_score >= dh_next->dh_score) { 344 KASSERT(dh->dh_onlist, ("dirhash: not on list")); 345 TAILQ_REMOVE(&ufsdirhash_list, dh, dh_list); 346 TAILQ_INSERT_AFTER(&ufsdirhash_list, dh_next, dh, 347 dh_list); 348 } 349 mtx_unlock(&ufsdirhash_mtx); 350 } else { 351 /* Already the last, though that could change as we wait. */ 352 mtx_lock(&dh->dh_mtx); 353 } 354 if (dh->dh_hash == NULL) { 355 mtx_unlock(&dh->dh_mtx); 356 ufsdirhash_free(ip); 357 return (EJUSTRETURN); 358 } 359 360 /* Update the score. */ 361 if (dh->dh_score < DH_SCOREMAX) 362 dh->dh_score++; 363 364 vp = ip->i_vnode; 365 bmask = VFSTOUFS(vp->v_mount)->um_mountp->mnt_stat.f_iosize - 1; 366 blkoff = -1; 367 bp = NULL; 368restart: 369 slot = ufsdirhash_hash(dh, name, namelen); 370 371 if (dh->dh_seqopt) { 372 /* 373 * Sequential access optimisation. dh_seqoff contains the 374 * offset of the directory entry immediately following 375 * the last entry that was looked up. Check if this offset 376 * appears in the hash chain for the name we are looking for. 377 */ 378 for (i = slot; (offset = DH_ENTRY(dh, i)) != DIRHASH_EMPTY; 379 i = WRAPINCR(i, dh->dh_hlen)) 380 if (offset == dh->dh_seqopt) 381 break; 382 if (offset == dh->dh_seqoff) { 383 /* 384 * We found an entry with the expected offset. This 385 * is probably the entry we want, but if not, the 386 * code below will turn off seqoff and retry. 387 */ 388 slot = i; 389 } else 390 dh->dh_seqopt = 0; 391 } 392 393 for (; (offset = DH_ENTRY(dh, slot)) != DIRHASH_EMPTY; 394 slot = WRAPINCR(slot, dh->dh_hlen)) { 395 if (offset == DIRHASH_DEL) 396 continue; 397 mtx_unlock(&dh->dh_mtx); 398 399 if (offset < 0 || offset >= ip->i_size) 400 panic("ufsdirhash_lookup: bad offset in hash array"); 401 if ((offset & ~bmask) != blkoff) { 402 if (bp != NULL) 403 brelse(bp); 404 blkoff = offset & ~bmask; 405 if (UFS_BLKATOFF(vp, (off_t)blkoff, NULL, &bp) != 0) 406 return (EJUSTRETURN); 407 } 408 dp = (struct direct *)(bp->b_data + (offset & bmask)); 409 if (dp->d_reclen == 0 || dp->d_reclen > 410 DIRBLKSIZ - (offset & (DIRBLKSIZ - 1))) { 411 /* Corrupted directory. */ 412 brelse(bp); 413 return (EJUSTRETURN); 414 } 415 if (dp->d_namlen == namelen && 416 bcmp(dp->d_name, name, namelen) == 0) { 417 /* Found. Get the prev offset if needed. */ 418 if (prevoffp != NULL) { 419 if (offset & (DIRBLKSIZ - 1)) { 420 prevoff = ufsdirhash_getprev(dp, 421 offset); 422 if (prevoff == -1) { 423 brelse(bp); 424 return (EJUSTRETURN); 425 } 426 } else 427 prevoff = offset; 428 *prevoffp = prevoff; 429 } 430 431 /* Check for sequential access, and update offset. */ 432 if (dh->dh_seqopt == 0 && dh->dh_seqoff == offset) 433 dh->dh_seqopt = 1; 434 dh->dh_seqoff = offset + DIRSIZ(0, dp); 435 436 *bpp = bp; 437 *offp = offset; 438 return (0); 439 } 440 441 mtx_lock(&dh->dh_mtx); 442 if (dh->dh_hash == NULL) { 443 mtx_unlock(&dh->dh_mtx); 444 if (bp != NULL) 445 brelse(bp); 446 ufsdirhash_free(ip); 447 return (EJUSTRETURN); 448 } 449 /* 450 * When the name doesn't match in the seqopt case, go back 451 * and search normally. 452 */ 453 if (dh->dh_seqopt) { 454 dh->dh_seqopt = 0; 455 goto restart; 456 } 457 } 458 mtx_unlock(&dh->dh_mtx); 459 if (bp != NULL) 460 brelse(bp); 461 return (ENOENT); 462} 463 464/* 465 * Find a directory block with room for 'slotneeded' bytes. Returns 466 * the offset of the directory entry that begins the free space. 467 * This will either be the offset of an existing entry that has free 468 * space at the end, or the offset of an entry with d_ino == 0 at 469 * the start of a DIRBLKSIZ block. 470 * 471 * To use the space, the caller may need to compact existing entries in 472 * the directory. The total number of bytes in all of the entries involved 473 * in the compaction is stored in *slotsize. In other words, all of 474 * the entries that must be compacted are exactly contained in the 475 * region beginning at the returned offset and spanning *slotsize bytes. 476 * 477 * Returns -1 if no space was found, indicating that the directory 478 * must be extended. 479 */ 480doff_t 481ufsdirhash_findfree(struct inode *ip, int slotneeded, int *slotsize) 482{ 483 struct direct *dp; 484 struct dirhash *dh; 485 struct buf *bp; 486 doff_t pos, slotstart; 487 int dirblock, error, freebytes, i; 488 489 if ((dh = ip->i_dirhash) == NULL) 490 return (-1); 491 mtx_lock(&dh->dh_mtx); 492 if (dh->dh_hash == NULL) { 493 mtx_unlock(&dh->dh_mtx); 494 ufsdirhash_free(ip); 495 return (-1); 496 } 497 498 /* Find a directory block with the desired free space. */ 499 dirblock = -1; 500 for (i = howmany(slotneeded, DIRALIGN); i <= DH_NFSTATS; i++) 501 if ((dirblock = dh->dh_firstfree[i]) != -1) 502 break; 503 if (dirblock == -1) { 504 mtx_unlock(&dh->dh_mtx); 505 return (-1); 506 } 507 508 KASSERT(dirblock < dh->dh_nblk && 509 dh->dh_blkfree[dirblock] >= howmany(slotneeded, DIRALIGN), 510 ("ufsdirhash_findfree: bad stats")); 511 mtx_unlock(&dh->dh_mtx); 512 pos = dirblock * DIRBLKSIZ; 513 error = UFS_BLKATOFF(ip->i_vnode, (off_t)pos, (char **)&dp, &bp); 514 if (error) 515 return (-1); 516 517 /* Find the first entry with free space. */ 518 for (i = 0; i < DIRBLKSIZ; ) { 519 if (dp->d_reclen == 0) { 520 brelse(bp); 521 return (-1); 522 } 523 if (dp->d_ino == 0 || dp->d_reclen > DIRSIZ(0, dp)) 524 break; 525 i += dp->d_reclen; 526 dp = (struct direct *)((char *)dp + dp->d_reclen); 527 } 528 if (i > DIRBLKSIZ) { 529 brelse(bp); 530 return (-1); 531 } 532 slotstart = pos + i; 533 534 /* Find the range of entries needed to get enough space */ 535 freebytes = 0; 536 while (i < DIRBLKSIZ && freebytes < slotneeded) { 537 freebytes += dp->d_reclen; 538 if (dp->d_ino != 0) 539 freebytes -= DIRSIZ(0, dp); 540 if (dp->d_reclen == 0) { 541 brelse(bp); 542 return (-1); 543 } 544 i += dp->d_reclen; 545 dp = (struct direct *)((char *)dp + dp->d_reclen); 546 } 547 if (i > DIRBLKSIZ) { 548 brelse(bp); 549 return (-1); 550 } 551 if (freebytes < slotneeded) 552 panic("ufsdirhash_findfree: free mismatch"); 553 brelse(bp); 554 *slotsize = pos + i - slotstart; 555 return (slotstart); 556} 557 558/* 559 * Return the start of the unused space at the end of a directory, or 560 * -1 if there are no trailing unused blocks. 561 */ 562doff_t 563ufsdirhash_enduseful(struct inode *ip) 564{ 565 566 struct dirhash *dh; 567 int i; 568 569 if ((dh = ip->i_dirhash) == NULL) 570 return (-1); 571 mtx_lock(&dh->dh_mtx); 572 if (dh->dh_hash == NULL) { 573 mtx_unlock(&dh->dh_mtx); 574 ufsdirhash_free(ip); 575 return (-1); 576 } 577 578 if (dh->dh_blkfree[dh->dh_dirblks - 1] != DIRBLKSIZ / DIRALIGN) { 579 mtx_unlock(&dh->dh_mtx); 580 return (-1); 581 } 582 583 for (i = dh->dh_dirblks - 1; i >= 0; i--) 584 if (dh->dh_blkfree[i] != DIRBLKSIZ / DIRALIGN) 585 break; 586 mtx_unlock(&dh->dh_mtx); 587 return ((doff_t)(i + 1) * DIRBLKSIZ); 588} 589 590/* 591 * Insert information into the hash about a new directory entry. dirp 592 * points to a struct direct containing the entry, and offset specifies 593 * the offset of this entry. 594 */ 595void 596ufsdirhash_add(struct inode *ip, struct direct *dirp, doff_t offset) 597{ 598 struct dirhash *dh; 599 int slot; 600 601 if ((dh = ip->i_dirhash) == NULL) 602 return; 603 mtx_lock(&dh->dh_mtx); 604 if (dh->dh_hash == NULL) { 605 mtx_unlock(&dh->dh_mtx); 606 ufsdirhash_free(ip); 607 return; 608 } 609 610 KASSERT(offset < dh->dh_dirblks * DIRBLKSIZ, 611 ("ufsdirhash_add: bad offset")); 612 /* 613 * Normal hash usage is < 66%. If the usage gets too high then 614 * remove the hash entirely and let it be rebuilt later. 615 */ 616 if (dh->dh_hused >= (dh->dh_hlen * 3) / 4) { 617 mtx_unlock(&dh->dh_mtx); 618 ufsdirhash_free(ip); 619 return; 620 } 621 622 /* Find a free hash slot (empty or deleted), and add the entry. */ 623 slot = ufsdirhash_hash(dh, dirp->d_name, dirp->d_namlen); 624 while (DH_ENTRY(dh, slot) >= 0) 625 slot = WRAPINCR(slot, dh->dh_hlen); 626 if (DH_ENTRY(dh, slot) == DIRHASH_EMPTY) 627 dh->dh_hused++; 628 DH_ENTRY(dh, slot) = offset; 629 630 /* Update the per-block summary info. */ 631 ufsdirhash_adjfree(dh, offset, -DIRSIZ(0, dirp)); 632 mtx_unlock(&dh->dh_mtx); 633} 634 635/* 636 * Remove the specified directory entry from the hash. The entry to remove 637 * is defined by the name in `dirp', which must exist at the specified 638 * `offset' within the directory. 639 */ 640void 641ufsdirhash_remove(struct inode *ip, struct direct *dirp, doff_t offset) 642{ 643 struct dirhash *dh; 644 int slot; 645 646 if ((dh = ip->i_dirhash) == NULL) 647 return; 648 mtx_lock(&dh->dh_mtx); 649 if (dh->dh_hash == NULL) { 650 mtx_unlock(&dh->dh_mtx); 651 ufsdirhash_free(ip); 652 return; 653 } 654 655 KASSERT(offset < dh->dh_dirblks * DIRBLKSIZ, 656 ("ufsdirhash_remove: bad offset")); 657 /* Find the entry */ 658 slot = ufsdirhash_findslot(dh, dirp->d_name, dirp->d_namlen, offset); 659 660 /* Remove the hash entry. */ 661 ufsdirhash_delslot(dh, slot); 662 663 /* Update the per-block summary info. */ 664 ufsdirhash_adjfree(dh, offset, DIRSIZ(0, dirp)); 665 mtx_unlock(&dh->dh_mtx); 666} 667 668/* 669 * Change the offset associated with a directory entry in the hash. Used 670 * when compacting directory blocks. 671 */ 672void 673ufsdirhash_move(struct inode *ip, struct direct *dirp, doff_t oldoff, 674 doff_t newoff) 675{ 676 struct dirhash *dh; 677 int slot; 678 679 if ((dh = ip->i_dirhash) == NULL) 680 return; 681 mtx_lock(&dh->dh_mtx); 682 if (dh->dh_hash == NULL) { 683 mtx_unlock(&dh->dh_mtx); 684 ufsdirhash_free(ip); 685 return; 686 } 687 688 KASSERT(oldoff < dh->dh_dirblks * DIRBLKSIZ && 689 newoff < dh->dh_dirblks * DIRBLKSIZ, 690 ("ufsdirhash_move: bad offset")); 691 /* Find the entry, and update the offset. */ 692 slot = ufsdirhash_findslot(dh, dirp->d_name, dirp->d_namlen, oldoff); 693 DH_ENTRY(dh, slot) = newoff; 694 mtx_unlock(&dh->dh_mtx); 695} 696 697/* 698 * Inform dirhash that the directory has grown by one block that 699 * begins at offset (i.e. the new length is offset + DIRBLKSIZ). 700 */ 701void 702ufsdirhash_newblk(struct inode *ip, doff_t offset) 703{ 704 struct dirhash *dh; 705 int block; 706 707 if ((dh = ip->i_dirhash) == NULL) 708 return; 709 mtx_lock(&dh->dh_mtx); 710 if (dh->dh_hash == NULL) { 711 mtx_unlock(&dh->dh_mtx); 712 ufsdirhash_free(ip); 713 return; 714 } 715 716 KASSERT(offset == dh->dh_dirblks * DIRBLKSIZ, 717 ("ufsdirhash_newblk: bad offset")); 718 block = offset / DIRBLKSIZ; 719 if (block >= dh->dh_nblk) { 720 /* Out of space; must rebuild. */ 721 mtx_unlock(&dh->dh_mtx); 722 ufsdirhash_free(ip); 723 return; 724 } 725 dh->dh_dirblks = block + 1; 726 727 /* Account for the new free block. */ 728 dh->dh_blkfree[block] = DIRBLKSIZ / DIRALIGN; 729 if (dh->dh_firstfree[DH_NFSTATS] == -1) 730 dh->dh_firstfree[DH_NFSTATS] = block; 731 mtx_unlock(&dh->dh_mtx); 732} 733 734/* 735 * Inform dirhash that the directory is being truncated. 736 */ 737void 738ufsdirhash_dirtrunc(struct inode *ip, doff_t offset) 739{ 740 struct dirhash *dh; 741 int block, i; 742 743 if ((dh = ip->i_dirhash) == NULL) 744 return; 745 mtx_lock(&dh->dh_mtx); 746 if (dh->dh_hash == NULL) { 747 mtx_unlock(&dh->dh_mtx); 748 ufsdirhash_free(ip); 749 return; 750 } 751 752 KASSERT(offset <= dh->dh_dirblks * DIRBLKSIZ, 753 ("ufsdirhash_dirtrunc: bad offset")); 754 block = howmany(offset, DIRBLKSIZ); 755 /* 756 * If the directory shrinks to less than 1/8 of dh_nblk blocks 757 * (about 20% of its original size due to the 50% extra added in 758 * ufsdirhash_build) then free it, and let the caller rebuild 759 * if necessary. 760 */ 761 if (block < dh->dh_nblk / 8 && dh->dh_narrays > 1) { 762 mtx_unlock(&dh->dh_mtx); 763 ufsdirhash_free(ip); 764 return; 765 } 766 767 /* 768 * Remove any `first free' information pertaining to the 769 * truncated blocks. All blocks we're removing should be 770 * completely unused. 771 */ 772 if (dh->dh_firstfree[DH_NFSTATS] >= block) 773 dh->dh_firstfree[DH_NFSTATS] = -1; 774 for (i = block; i < dh->dh_dirblks; i++) 775 if (dh->dh_blkfree[i] != DIRBLKSIZ / DIRALIGN) 776 panic("ufsdirhash_dirtrunc: blocks in use"); 777 for (i = 0; i < DH_NFSTATS; i++) 778 if (dh->dh_firstfree[i] >= block) 779 panic("ufsdirhash_dirtrunc: first free corrupt"); 780 dh->dh_dirblks = block; 781 mtx_unlock(&dh->dh_mtx); 782} 783 784/* 785 * Debugging function to check that the dirhash information about 786 * a directory block matches its actual contents. Panics if a mismatch 787 * is detected. 788 * 789 * On entry, `buf' should point to the start of an in-core 790 * DIRBLKSIZ-sized directory block, and `offset' should contain the 791 * offset from the start of the directory of that block. 792 */ 793void 794ufsdirhash_checkblock(struct inode *ip, char *buf, doff_t offset) 795{ 796 struct dirhash *dh; 797 struct direct *dp; 798 int block, ffslot, i, nfree; 799 800 if (!ufs_dirhashcheck) 801 return; 802 if ((dh = ip->i_dirhash) == NULL) 803 return; 804 mtx_lock(&dh->dh_mtx); 805 if (dh->dh_hash == NULL) { 806 mtx_unlock(&dh->dh_mtx); 807 ufsdirhash_free(ip); 808 return; 809 } 810 811 block = offset / DIRBLKSIZ; 812 if ((offset & (DIRBLKSIZ - 1)) != 0 || block >= dh->dh_dirblks) 813 panic("ufsdirhash_checkblock: bad offset"); 814 815 nfree = 0; 816 for (i = 0; i < DIRBLKSIZ; i += dp->d_reclen) { 817 dp = (struct direct *)(buf + i); 818 if (dp->d_reclen == 0 || i + dp->d_reclen > DIRBLKSIZ) 819 panic("ufsdirhash_checkblock: bad dir"); 820 821 if (dp->d_ino == 0) { 822#if 0 823 /* 824 * XXX entries with d_ino == 0 should only occur 825 * at the start of a DIRBLKSIZ block. However the 826 * ufs code is tolerant of such entries at other 827 * offsets, and fsck does not fix them. 828 */ 829 if (i != 0) 830 panic("ufsdirhash_checkblock: bad dir inode"); 831#endif 832 nfree += dp->d_reclen; 833 continue; 834 } 835 836 /* Check that the entry exists (will panic if it doesn't). */ 837 ufsdirhash_findslot(dh, dp->d_name, dp->d_namlen, offset + i); 838 839 nfree += dp->d_reclen - DIRSIZ(0, dp); 840 } 841 if (i != DIRBLKSIZ) 842 panic("ufsdirhash_checkblock: bad dir end"); 843 844 if (dh->dh_blkfree[block] * DIRALIGN != nfree) 845 panic("ufsdirhash_checkblock: bad free count"); 846 847 ffslot = nfree / DIRALIGN; 848 if (ffslot > DH_NFSTATS) 849 ffslot = DH_NFSTATS; 850 for (i = 0; i <= DH_NFSTATS; i++) 851 if (dh->dh_firstfree[i] == block && i != ffslot) 852 panic("ufsdirhash_checkblock: bad first-free"); 853 mtx_unlock(&dh->dh_mtx); 854} 855 856/* 857 * Hash the specified filename into a dirhash slot. 858 */ 859static int 860ufsdirhash_hash(struct dirhash *dh, char *name, int namelen) 861{ 862 return (fnv_32_buf(name, namelen, FNV1_32_INIT) % dh->dh_hlen); 863} 864 865/* 866 * Adjust the number of free bytes in the block containing `offset' 867 * by the value specified by `diff'. 868 * 869 * The caller must ensure we have exclusive access to `dh'; normally 870 * that means that dh_mtx should be held, but this is also called 871 * from ufsdirhash_build() where exclusive access can be assumed. 872 */ 873static void 874ufsdirhash_adjfree(struct dirhash *dh, doff_t offset, int diff) 875{ 876 int block, i, nfidx, ofidx; 877 878 /* Update the per-block summary info. */ 879 block = offset / DIRBLKSIZ; 880 KASSERT(block < dh->dh_nblk && block < dh->dh_dirblks, 881 ("dirhash bad offset")); 882 ofidx = dh->dh_blkfree[block]; 883 if (ofidx > DH_NFSTATS) 884 ofidx = DH_NFSTATS; 885 dh->dh_blkfree[block] = (int)dh->dh_blkfree[block] + (diff / DIRALIGN); 886 nfidx = dh->dh_blkfree[block]; 887 if (nfidx > DH_NFSTATS) 888 nfidx = DH_NFSTATS; 889 890 /* Update the `first free' list if necessary. */ 891 if (ofidx != nfidx) { 892 /* If removing, scan forward for the next block. */ 893 if (dh->dh_firstfree[ofidx] == block) { 894 for (i = block + 1; i < dh->dh_dirblks; i++) 895 if (dh->dh_blkfree[i] == ofidx) 896 break; 897 dh->dh_firstfree[ofidx] = (i < dh->dh_dirblks) ? i : -1; 898 } 899 900 /* Make this the new `first free' if necessary */ 901 if (dh->dh_firstfree[nfidx] > block || 902 dh->dh_firstfree[nfidx] == -1) 903 dh->dh_firstfree[nfidx] = block; 904 } 905} 906 907/* 908 * Find the specified name which should have the specified offset. 909 * Returns a slot number, and panics on failure. 910 * 911 * `dh' must be locked on entry and remains so on return. 912 */ 913static int 914ufsdirhash_findslot(struct dirhash *dh, char *name, int namelen, doff_t offset) 915{ 916 int slot; 917 918 mtx_assert(&dh->dh_mtx, MA_OWNED); 919 920 /* Find the entry. */ 921 KASSERT(dh->dh_hused < dh->dh_hlen, ("dirhash find full")); 922 slot = ufsdirhash_hash(dh, name, namelen); 923 while (DH_ENTRY(dh, slot) != offset && 924 DH_ENTRY(dh, slot) != DIRHASH_EMPTY) 925 slot = WRAPINCR(slot, dh->dh_hlen); 926 if (DH_ENTRY(dh, slot) != offset) 927 panic("ufsdirhash_findslot: '%.*s' not found", namelen, name); 928 929 return (slot); 930} 931 932/* 933 * Remove the entry corresponding to the specified slot from the hash array. 934 * 935 * `dh' must be locked on entry and remains so on return. 936 */ 937static void 938ufsdirhash_delslot(struct dirhash *dh, int slot) 939{ 940 int i; 941 942 mtx_assert(&dh->dh_mtx, MA_OWNED); 943 944 /* Mark the entry as deleted. */ 945 DH_ENTRY(dh, slot) = DIRHASH_DEL; 946 947 /* If this is the end of a chain of DIRHASH_DEL slots, remove them. */ 948 for (i = slot; DH_ENTRY(dh, i) == DIRHASH_DEL; ) 949 i = WRAPINCR(i, dh->dh_hlen); 950 if (DH_ENTRY(dh, i) == DIRHASH_EMPTY) { 951 for (i = slot; DH_ENTRY(dh, i) == DIRHASH_DEL; ) { 952 DH_ENTRY(dh, i) = DIRHASH_EMPTY; 953 dh->dh_hused--; 954 i = WRAPINCR(i, dh->dh_hlen); 955 } 956 KASSERT(dh->dh_hused >= 0, ("ufsdirhash_delslot neg hlen")); 957 } 958} 959 960/* 961 * Given a directory entry and its offset, find the offset of the 962 * previous entry in the same DIRBLKSIZ-sized block. Returns an 963 * offset, or -1 if there is no previous entry in the block or some 964 * other problem occurred. 965 */ 966static doff_t 967ufsdirhash_getprev(struct direct *dirp, doff_t offset) 968{ 969 struct direct *dp; 970 char *blkbuf; 971 doff_t blkoff, prevoff; 972 int entrypos, i; 973 974 blkoff = offset & ~(DIRBLKSIZ - 1); /* offset of start of block */ 975 entrypos = offset & (DIRBLKSIZ - 1); /* entry relative to block */ 976 blkbuf = (char *)dirp - entrypos; 977 prevoff = blkoff; 978 979 /* If `offset' is the start of a block, there is no previous entry. */ 980 if (entrypos == 0) 981 return (-1); 982 983 /* Scan from the start of the block until we get to the entry. */ 984 for (i = 0; i < entrypos; i += dp->d_reclen) { 985 dp = (struct direct *)(blkbuf + i); 986 if (dp->d_reclen == 0 || i + dp->d_reclen > entrypos) 987 return (-1); /* Corrupted directory. */ 988 prevoff = blkoff + i; 989 } 990 return (prevoff); 991} 992 993/* 994 * Try to free up `wanted' bytes by stealing memory from existing 995 * dirhashes. Returns zero with ufsdirhash_mtx locked if successful. 996 */ 997static int 998ufsdirhash_recycle(int wanted) 999{ 1000 struct dirhash *dh; 1001 doff_t **hash; 1002 u_int8_t *blkfree; 1003 int i, mem, narrays; 1004 1005 mtx_lock(&ufsdirhash_mtx); 1006 while (wanted + ufs_dirhashmem > ufs_dirhashmaxmem) { 1007 /* Find a dirhash, and lock it. */ 1008 if ((dh = TAILQ_FIRST(&ufsdirhash_list)) == NULL) { 1009 mtx_unlock(&ufsdirhash_mtx); 1010 return (-1); 1011 } 1012 mtx_lock(&dh->dh_mtx); 1013 KASSERT(dh->dh_hash != NULL, ("dirhash: NULL hash on list")); 1014 1015 /* Decrement the score; only recycle if it becomes zero. */ 1016 if (--dh->dh_score > 0) { 1017 mtx_unlock(&dh->dh_mtx); 1018 mtx_unlock(&ufsdirhash_mtx); 1019 return (-1); 1020 } 1021 1022 /* Remove it from the list and detach its memory. */ 1023 TAILQ_REMOVE(&ufsdirhash_list, dh, dh_list); 1024 dh->dh_onlist = 0; 1025 hash = dh->dh_hash; 1026 dh->dh_hash = NULL; 1027 blkfree = dh->dh_blkfree; 1028 dh->dh_blkfree = NULL; 1029 narrays = dh->dh_narrays; 1030 mem = narrays * sizeof(*dh->dh_hash) + 1031 narrays * DH_NBLKOFF * sizeof(**dh->dh_hash) + 1032 dh->dh_nblk * sizeof(*dh->dh_blkfree); 1033 1034 /* Unlock everything, free the detached memory. */ 1035 mtx_unlock(&dh->dh_mtx); 1036 mtx_unlock(&ufsdirhash_mtx); 1037 for (i = 0; i < narrays; i++) 1038 zfree(ufsdirhash_zone, hash[i]); 1039 FREE(hash, M_DIRHASH); 1040 FREE(blkfree, M_DIRHASH); 1041 1042 /* Account for the returned memory, and repeat if necessary. */ 1043 mtx_lock(&ufsdirhash_mtx); 1044 ufs_dirhashmem -= mem; 1045 } 1046 /* Success; return with ufsdirhash_mtx locked. */ 1047 return (0); 1048} 1049 1050 1051static void 1052ufsdirhash_init() 1053{ 1054 ufsdirhash_zone = zinit("DIRHASH", DH_NBLKOFF * sizeof(daddr_t), 0, 1055 0, 1); 1056 mtx_init(&ufsdirhash_mtx, "dirhash list", MTX_DEF); 1057 TAILQ_INIT(&ufsdirhash_list); 1058} 1059SYSINIT(ufsdirhash, SI_SUB_PSEUDO, SI_ORDER_ANY, ufsdirhash_init, NULL) 1060 1061 1062#endif /* UFS_DIRHASH */ 1063