ufs_dirhash.c revision 79561
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 79561 2001-07-10 21:21:29Z 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 vp = ip->i_vnode; 139 /* Allocate 50% more entries than this dir size could ever need. */ 140 KASSERT(ip->i_size >= DIRBLKSIZ, ("ufsdirhash_build size")); 141 nslots = ip->i_size / DIRECTSIZ(1); 142 nslots = (nslots * 3 + 1) / 2; 143 narrays = howmany(nslots, DH_NBLKOFF); 144 nslots = narrays * DH_NBLKOFF; 145 dirblocks = howmany(ip->i_size, DIRBLKSIZ); 146 nblocks = (dirblocks * 3 + 1) / 2; 147 148 memreqd = sizeof(*dh) + narrays * sizeof(*dh->dh_hash) + 149 narrays * DH_NBLKOFF * sizeof(**dh->dh_hash) + 150 nblocks * sizeof(*dh->dh_blkfree); 151 mtx_lock(&ufsdirhash_mtx); 152 if (memreqd + ufs_dirhashmem > ufs_dirhashmaxmem) { 153 mtx_unlock(&ufsdirhash_mtx); 154 if (memreqd > ufs_dirhashmaxmem / 2) 155 return (-1); 156 157 /* Try to free some space. */ 158 if (ufsdirhash_recycle(memreqd) != 0) 159 return (-1); 160 /* Enough was freed, and ufsdirhash_mtx has been locked. */ 161 } 162 ufs_dirhashmem += memreqd; 163 mtx_unlock(&ufsdirhash_mtx); 164 165 /* 166 * Use non-blocking mallocs so that we will revert to a linear 167 * lookup on failure rather than potentially blocking forever. 168 */ 169 MALLOC(dh, struct dirhash *, sizeof *dh, M_DIRHASH, M_NOWAIT | M_ZERO); 170 if (dh == NULL) 171 return (-1); 172 MALLOC(dh->dh_hash, doff_t **, narrays * sizeof(dh->dh_hash[0]), 173 M_DIRHASH, M_NOWAIT | M_ZERO); 174 MALLOC(dh->dh_blkfree, u_int8_t *, nblocks * sizeof(dh->dh_blkfree[0]), 175 M_DIRHASH, M_NOWAIT); 176 if (dh->dh_hash == NULL || dh->dh_blkfree == NULL) 177 goto fail; 178 for (i = 0; i < narrays; i++) { 179 if ((dh->dh_hash[i] = zalloc(ufsdirhash_zone)) == NULL) 180 goto fail; 181 for (j = 0; j < DH_NBLKOFF; j++) 182 dh->dh_hash[i][j] = DIRHASH_EMPTY; 183 } 184 185 /* Initialise the hash table and block statistics. */ 186 mtx_init(&dh->dh_mtx, "dirhash", MTX_DEF); 187 dh->dh_narrays = narrays; 188 dh->dh_hlen = nslots; 189 dh->dh_nblk = nblocks; 190 dh->dh_dirblks = dirblocks; 191 for (i = 0; i < dirblocks; i++) 192 dh->dh_blkfree[i] = DIRBLKSIZ / DIRALIGN; 193 for (i = 0; i < DH_NFSTATS; i++) 194 dh->dh_firstfree[i] = -1; 195 dh->dh_firstfree[DH_NFSTATS] = 0; 196 dh->dh_seqopt = 0; 197 dh->dh_seqoff = 0; 198 dh->dh_score = DH_SCOREINIT; 199 ip->i_dirhash = dh; 200 201 bmask = VFSTOUFS(vp->v_mount)->um_mountp->mnt_stat.f_iosize - 1; 202 pos = 0; 203 while (pos < ip->i_size) { 204 /* If necessary, get the next directory block. */ 205 if ((pos & bmask) == 0) { 206 if (bp != NULL) 207 brelse(bp); 208 if (UFS_BLKATOFF(vp, (off_t)pos, NULL, &bp) != 0) 209 goto fail; 210 } 211 212 /* Add this entry to the hash. */ 213 ep = (struct direct *)((char *)bp->b_data + (pos & bmask)); 214 if (ep->d_reclen == 0 || ep->d_reclen > 215 DIRBLKSIZ - (pos & (DIRBLKSIZ - 1))) { 216 /* Corrupted directory. */ 217 brelse(bp); 218 goto fail; 219 } 220 if (ep->d_ino != 0) { 221 /* Add the entry (simplified ufsdirhash_add). */ 222 slot = ufsdirhash_hash(dh, ep->d_name, ep->d_namlen); 223 while (DH_ENTRY(dh, slot) != DIRHASH_EMPTY) 224 slot = WRAPINCR(slot, dh->dh_hlen); 225 dh->dh_hused++; 226 DH_ENTRY(dh, slot) = pos; 227 ufsdirhash_adjfree(dh, pos, -DIRSIZ(0, ep)); 228 } 229 pos += ep->d_reclen; 230 } 231 232 if (bp != NULL) 233 brelse(bp); 234 mtx_lock(&ufsdirhash_mtx); 235 TAILQ_INSERT_TAIL(&ufsdirhash_list, dh, dh_list); 236 dh->dh_onlist = 1; 237 mtx_unlock(&ufsdirhash_mtx); 238 return (0); 239 240fail: 241 if (dh->dh_hash != NULL) { 242 for (i = 0; i < narrays; i++) 243 if (dh->dh_hash[i] != NULL) 244 zfree(ufsdirhash_zone, dh->dh_hash[i]); 245 FREE(dh->dh_hash, M_DIRHASH); 246 } 247 if (dh->dh_blkfree != NULL) 248 FREE(dh->dh_blkfree, M_DIRHASH); 249 FREE(dh, M_DIRHASH); 250 ip->i_dirhash = NULL; 251 mtx_lock(&ufsdirhash_mtx); 252 ufs_dirhashmem -= memreqd; 253 mtx_unlock(&ufsdirhash_mtx); 254 return (-1); 255} 256 257/* 258 * Free any hash table associated with inode 'ip'. 259 */ 260void 261ufsdirhash_free(struct inode *ip) 262{ 263 struct dirhash *dh; 264 int i, mem; 265 266 if ((dh = ip->i_dirhash) == NULL) 267 return; 268 mtx_lock(&ufsdirhash_mtx); 269 mtx_lock(&dh->dh_mtx); 270 if (dh->dh_onlist) 271 TAILQ_REMOVE(&ufsdirhash_list, dh, dh_list); 272 mtx_unlock(&dh->dh_mtx); 273 mtx_unlock(&ufsdirhash_mtx); 274 275 /* The dirhash pointed to by 'dh' is exclusively ours now. */ 276 277 mem = sizeof(*dh); 278 if (dh->dh_hash != NULL) { 279 for (i = 0; i < dh->dh_narrays; i++) 280 zfree(ufsdirhash_zone, dh->dh_hash[i]); 281 FREE(dh->dh_hash, M_DIRHASH); 282 FREE(dh->dh_blkfree, M_DIRHASH); 283 mem += dh->dh_narrays * sizeof(*dh->dh_hash) + 284 dh->dh_narrays * DH_NBLKOFF * sizeof(**dh->dh_hash) + 285 dh->dh_nblk * sizeof(*dh->dh_blkfree); 286 } 287 mtx_destroy(&dh->dh_mtx); 288 FREE(dh, M_DIRHASH); 289 ip->i_dirhash = NULL; 290 291 mtx_lock(&ufsdirhash_mtx); 292 ufs_dirhashmem -= mem; 293 mtx_unlock(&ufsdirhash_mtx); 294} 295 296/* 297 * Find the offset of the specified name within the given inode. 298 * Returns 0 on success, ENOENT if the entry does not exist, or 299 * EJUSTRETURN if the caller should revert to a linear search. 300 * 301 * If successful, the directory offset is stored in *offp. If 302 * prevoffp is non-NULL, the offset of the previous entry within 303 * the DIRBLKSIZ-sized block is stored in *prevoffp (if the entry 304 * is the first in a block, the start of the block is used). 305 */ 306int 307ufsdirhash_lookup(struct inode *ip, char *name, int namelen, doff_t *offp, 308 doff_t *prevoffp) 309{ 310 struct dirhash *dh, *dh_next; 311 struct direct *dp; 312 struct vnode *vp; 313 struct buf *bp; 314 doff_t blkoff, bmask, offset, prevoff; 315 int i, slot; 316 317 if ((dh = ip->i_dirhash) == NULL) 318 return (EJUSTRETURN); 319 /* 320 * Move this dirhash towards the end of the list if it has a 321 * score higher than the next entry, and aquire the dh_mtx. 322 * Optimise the case where it's already the last by performing 323 * an unlocked read of the TAILQ_NEXT pointer. 324 * 325 * In both cases, end up holding just dh_mtx. 326 */ 327 if (TAILQ_NEXT(dh, dh_list) != NULL) { 328 mtx_lock(&ufsdirhash_mtx); 329 mtx_lock(&dh->dh_mtx); 330 /* 331 * If the new score will be greater than that of the next 332 * entry, then move this entry past it. With both mutexes 333 * held, dh_next won't go away, but its dh_score could 334 * change; that's not important since it is just a hint. 335 */ 336 if (dh->dh_hash != NULL && 337 (dh_next = TAILQ_NEXT(dh, dh_list)) != NULL && 338 dh->dh_score >= dh_next->dh_score) { 339 KASSERT(dh->dh_onlist, ("dirhash: not on list")); 340 TAILQ_REMOVE(&ufsdirhash_list, dh, dh_list); 341 TAILQ_INSERT_AFTER(&ufsdirhash_list, dh_next, dh, 342 dh_list); 343 } 344 mtx_unlock(&ufsdirhash_mtx); 345 } else { 346 /* Already the last, though that could change as we wait. */ 347 mtx_lock(&dh->dh_mtx); 348 } 349 if (dh->dh_hash == NULL) { 350 mtx_unlock(&dh->dh_mtx); 351 ufsdirhash_free(ip); 352 return (EJUSTRETURN); 353 } 354 355 /* Update the score. */ 356 if (dh->dh_score < DH_SCOREMAX) 357 dh->dh_score++; 358 359 vp = ip->i_vnode; 360 bmask = VFSTOUFS(vp->v_mount)->um_mountp->mnt_stat.f_iosize - 1; 361 blkoff = -1; 362 bp = NULL; 363restart: 364 slot = ufsdirhash_hash(dh, name, namelen); 365 366 if (dh->dh_seqopt) { 367 /* 368 * Sequential access optimisation. dh_seqoff contains the 369 * offset of the directory entry immediately following 370 * the last entry that was looked up. Check if this offset 371 * appears in the hash chain for the name we are looking for. 372 */ 373 for (i = slot; (offset = DH_ENTRY(dh, i)) != DIRHASH_EMPTY; 374 i = WRAPINCR(i, dh->dh_hlen)) 375 if (offset == dh->dh_seqopt) 376 break; 377 if (offset == dh->dh_seqoff) { 378 /* 379 * We found an entry with the expected offset. This 380 * is probably the entry we want, but if not, the 381 * code below will turn off seqoff and retry. 382 */ 383 slot = i; 384 } else 385 dh->dh_seqopt = 0; 386 } 387 388 for (; (offset = DH_ENTRY(dh, slot)) != DIRHASH_EMPTY; 389 slot = WRAPINCR(slot, dh->dh_hlen)) { 390 if (offset == DIRHASH_DEL) 391 continue; 392 mtx_unlock(&dh->dh_mtx); 393 394 if (offset < 0 || offset >= ip->i_size) 395 panic("ufsdirhash_lookup: bad offset in hash array"); 396 if ((offset & ~bmask) != blkoff) { 397 if (bp != NULL) 398 brelse(bp); 399 blkoff = offset & ~bmask; 400 if (UFS_BLKATOFF(vp, (off_t)blkoff, NULL, &bp) != 0) 401 return (EJUSTRETURN); 402 } 403 dp = (struct direct *)(bp->b_data + (offset & bmask)); 404 if (dp->d_reclen == 0 || dp->d_reclen > 405 DIRBLKSIZ - (offset & (DIRBLKSIZ - 1))) { 406 /* Corrupted directory. */ 407 brelse(bp); 408 return (EJUSTRETURN); 409 } 410 if (dp->d_namlen == namelen && 411 bcmp(dp->d_name, name, namelen) == 0) { 412 /* Found. Get the prev offset if needed. */ 413 if (prevoffp != NULL) { 414 if (offset & (DIRBLKSIZ - 1)) { 415 prevoff = ufsdirhash_getprev(dp, 416 offset); 417 if (prevoff == -1) { 418 brelse(bp); 419 return (EJUSTRETURN); 420 } 421 } else 422 prevoff = offset; 423 *prevoffp = prevoff; 424 } 425 426 /* Check for sequential access, and update offset. */ 427 if (dh->dh_seqopt == 0 && dh->dh_seqoff == offset) 428 dh->dh_seqopt = 1; 429 dh->dh_seqoff = offset + DIRSIZ(0, dp); 430 431 brelse(bp); 432 *offp = offset; 433 return (0); 434 } 435 436 mtx_lock(&dh->dh_mtx); 437 if (dh->dh_hash == NULL) { 438 mtx_unlock(&dh->dh_mtx); 439 if (bp != NULL) 440 brelse(bp); 441 ufsdirhash_free(ip); 442 return (EJUSTRETURN); 443 } 444 /* 445 * When the name doesn't match in the seqopt case, go back 446 * and search normally. 447 */ 448 if (dh->dh_seqopt) { 449 dh->dh_seqopt = 0; 450 goto restart; 451 } 452 } 453 mtx_unlock(&dh->dh_mtx); 454 if (bp != NULL) 455 brelse(bp); 456 return (ENOENT); 457} 458 459/* 460 * Find a directory block with room for 'slotneeded' bytes. Returns 461 * the offset of the directory entry that begins the free space. 462 * This will either be the offset of an existing entry that has free 463 * space at the end, or the offset of an entry with d_ino == 0 at 464 * the start of a DIRBLKSIZ block. 465 * 466 * To use the space, the caller may need to compact existing entries in 467 * the directory. The total number of bytes in all of the entries involved 468 * in the compaction is stored in *slotsize. In other words, all of 469 * the entries that must be compacted are exactly contained in the 470 * region beginning at the returned offset and spanning *slotsize bytes. 471 * 472 * Returns -1 if no space was found, indicating that the directory 473 * must be extended. 474 */ 475doff_t 476ufsdirhash_findfree(struct inode *ip, int slotneeded, int *slotsize) 477{ 478 struct direct *dp; 479 struct dirhash *dh; 480 struct buf *bp; 481 doff_t pos, slotstart; 482 int dirblock, error, freebytes, i; 483 484 if ((dh = ip->i_dirhash) == NULL) 485 return (-1); 486 mtx_lock(&dh->dh_mtx); 487 if (dh->dh_hash == NULL) { 488 mtx_unlock(&dh->dh_mtx); 489 ufsdirhash_free(ip); 490 return (-1); 491 } 492 493 /* Find a directory block with the desired free space. */ 494 dirblock = -1; 495 for (i = howmany(slotneeded, DIRALIGN); i <= DH_NFSTATS; i++) 496 if ((dirblock = dh->dh_firstfree[i]) != -1) 497 break; 498 if (dirblock == -1) { 499 mtx_unlock(&dh->dh_mtx); 500 return (-1); 501 } 502 503 KASSERT(dirblock < dh->dh_nblk && 504 dh->dh_blkfree[dirblock] >= howmany(slotneeded, DIRALIGN), 505 ("ufsdirhash_findfree: bad stats")); 506 mtx_unlock(&dh->dh_mtx); 507 pos = dirblock * DIRBLKSIZ; 508 error = UFS_BLKATOFF(ip->i_vnode, (off_t)pos, (char **)&dp, &bp); 509 if (error) 510 return (-1); 511 512 /* Find the first entry with free space. */ 513 for (i = 0; i < DIRBLKSIZ; ) { 514 if (dp->d_reclen == 0) { 515 brelse(bp); 516 return (-1); 517 } 518 if (dp->d_ino == 0 || dp->d_reclen > DIRSIZ(0, dp)) 519 break; 520 i += dp->d_reclen; 521 dp = (struct direct *)((char *)dp + dp->d_reclen); 522 } 523 if (i > DIRBLKSIZ) { 524 brelse(bp); 525 return (-1); 526 } 527 slotstart = pos + i; 528 529 /* Find the range of entries needed to get enough space */ 530 freebytes = 0; 531 while (i < DIRBLKSIZ && freebytes < slotneeded) { 532 freebytes += dp->d_reclen; 533 if (dp->d_ino != 0) 534 freebytes -= DIRSIZ(0, dp); 535 if (dp->d_reclen == 0) { 536 brelse(bp); 537 return (-1); 538 } 539 i += dp->d_reclen; 540 dp = (struct direct *)((char *)dp + dp->d_reclen); 541 } 542 if (i > DIRBLKSIZ) { 543 brelse(bp); 544 return (-1); 545 } 546 if (freebytes < slotneeded) 547 panic("ufsdirhash_findfree: free mismatch"); 548 brelse(bp); 549 *slotsize = pos + i - slotstart; 550 return (slotstart); 551} 552 553/* 554 * Return the start of the unused space at the end of a directory, or 555 * -1 if there are no trailing unused blocks. 556 */ 557doff_t 558ufsdirhash_enduseful(struct inode *ip) 559{ 560 561 struct dirhash *dh; 562 int i; 563 564 if ((dh = ip->i_dirhash) == NULL) 565 return (-1); 566 mtx_lock(&dh->dh_mtx); 567 if (dh->dh_hash == NULL) { 568 mtx_unlock(&dh->dh_mtx); 569 ufsdirhash_free(ip); 570 return (-1); 571 } 572 573 if (dh->dh_blkfree[dh->dh_dirblks - 1] != DIRBLKSIZ / DIRALIGN) { 574 mtx_unlock(&dh->dh_mtx); 575 return (-1); 576 } 577 578 for (i = dh->dh_dirblks - 1; i >= 0; i--) 579 if (dh->dh_blkfree[i] != DIRBLKSIZ / DIRALIGN) 580 break; 581 mtx_unlock(&dh->dh_mtx); 582 return ((doff_t)(i + 1) * DIRBLKSIZ); 583} 584 585/* 586 * Insert information into the hash about a new directory entry. dirp 587 * points to a struct direct containing the entry, and offset specifies 588 * the offset of this entry. 589 */ 590void 591ufsdirhash_add(struct inode *ip, struct direct *dirp, doff_t offset) 592{ 593 struct dirhash *dh; 594 int slot; 595 596 if ((dh = ip->i_dirhash) == NULL) 597 return; 598 mtx_lock(&dh->dh_mtx); 599 if (dh->dh_hash == NULL) { 600 mtx_unlock(&dh->dh_mtx); 601 ufsdirhash_free(ip); 602 return; 603 } 604 605 KASSERT(offset < dh->dh_dirblks * DIRBLKSIZ, 606 ("ufsdirhash_add: bad offset")); 607 /* 608 * Normal hash usage is < 66%. If the usage gets too high then 609 * remove the hash entirely and let it be rebuilt later. 610 */ 611 if (dh->dh_hused >= (dh->dh_hlen * 3) / 4) { 612 mtx_unlock(&dh->dh_mtx); 613 ufsdirhash_free(ip); 614 return; 615 } 616 617 /* Find a free hash slot (empty or deleted), and add the entry. */ 618 slot = ufsdirhash_hash(dh, dirp->d_name, dirp->d_namlen); 619 while (DH_ENTRY(dh, slot) >= 0) 620 slot = WRAPINCR(slot, dh->dh_hlen); 621 if (DH_ENTRY(dh, slot) == DIRHASH_EMPTY) 622 dh->dh_hused++; 623 DH_ENTRY(dh, slot) = offset; 624 625 /* Update the per-block summary info. */ 626 ufsdirhash_adjfree(dh, offset, -DIRSIZ(0, dirp)); 627 mtx_unlock(&dh->dh_mtx); 628} 629 630/* 631 * Remove the specified directory entry from the hash. The entry to remove 632 * is defined by the name in `dirp', which must exist at the specified 633 * `offset' within the directory. 634 */ 635void 636ufsdirhash_remove(struct inode *ip, struct direct *dirp, doff_t offset) 637{ 638 struct dirhash *dh; 639 int slot; 640 641 if ((dh = ip->i_dirhash) == NULL) 642 return; 643 mtx_lock(&dh->dh_mtx); 644 if (dh->dh_hash == NULL) { 645 mtx_unlock(&dh->dh_mtx); 646 ufsdirhash_free(ip); 647 return; 648 } 649 650 KASSERT(offset < dh->dh_dirblks * DIRBLKSIZ, 651 ("ufsdirhash_remove: bad offset")); 652 /* Find the entry */ 653 slot = ufsdirhash_findslot(dh, dirp->d_name, dirp->d_namlen, offset); 654 655 /* Remove the hash entry. */ 656 ufsdirhash_delslot(dh, slot); 657 658 /* Update the per-block summary info. */ 659 ufsdirhash_adjfree(dh, offset, DIRSIZ(0, dirp)); 660 mtx_unlock(&dh->dh_mtx); 661} 662 663/* 664 * Change the offset associated with a directory entry in the hash. Used 665 * when compacting directory blocks. 666 */ 667void 668ufsdirhash_move(struct inode *ip, struct direct *dirp, doff_t oldoff, 669 doff_t newoff) 670{ 671 struct dirhash *dh; 672 int slot; 673 674 if ((dh = ip->i_dirhash) == NULL) 675 return; 676 mtx_lock(&dh->dh_mtx); 677 if (dh->dh_hash == NULL) { 678 mtx_unlock(&dh->dh_mtx); 679 ufsdirhash_free(ip); 680 return; 681 } 682 683 KASSERT(oldoff < dh->dh_dirblks * DIRBLKSIZ && 684 newoff < dh->dh_dirblks * DIRBLKSIZ, 685 ("ufsdirhash_move: bad offset")); 686 /* Find the entry, and update the offset. */ 687 slot = ufsdirhash_findslot(dh, dirp->d_name, dirp->d_namlen, oldoff); 688 DH_ENTRY(dh, slot) = newoff; 689 mtx_unlock(&dh->dh_mtx); 690} 691 692/* 693 * Inform dirhash that the directory has grown by one block that 694 * begins at offset (i.e. the new length is offset + DIRBLKSIZ). 695 */ 696void 697ufsdirhash_newblk(struct inode *ip, doff_t offset) 698{ 699 struct dirhash *dh; 700 int block; 701 702 if ((dh = ip->i_dirhash) == NULL) 703 return; 704 mtx_lock(&dh->dh_mtx); 705 if (dh->dh_hash == NULL) { 706 mtx_unlock(&dh->dh_mtx); 707 ufsdirhash_free(ip); 708 return; 709 } 710 711 KASSERT(offset == dh->dh_dirblks * DIRBLKSIZ, 712 ("ufsdirhash_newblk: bad offset")); 713 block = offset / DIRBLKSIZ; 714 if (block >= dh->dh_nblk) { 715 /* Out of space; must rebuild. */ 716 mtx_unlock(&dh->dh_mtx); 717 ufsdirhash_free(ip); 718 return; 719 } 720 dh->dh_dirblks = block + 1; 721 722 /* Account for the new free block. */ 723 dh->dh_blkfree[block] = DIRBLKSIZ / DIRALIGN; 724 if (dh->dh_firstfree[DH_NFSTATS] == -1) 725 dh->dh_firstfree[DH_NFSTATS] = block; 726 mtx_unlock(&dh->dh_mtx); 727} 728 729/* 730 * Inform dirhash that the directory is being truncated. 731 */ 732void 733ufsdirhash_dirtrunc(struct inode *ip, doff_t offset) 734{ 735 struct dirhash *dh; 736 int block, i; 737 738 if ((dh = ip->i_dirhash) == NULL) 739 return; 740 mtx_lock(&dh->dh_mtx); 741 if (dh->dh_hash == NULL) { 742 mtx_unlock(&dh->dh_mtx); 743 ufsdirhash_free(ip); 744 return; 745 } 746 747 KASSERT(offset <= dh->dh_dirblks * DIRBLKSIZ, 748 ("ufsdirhash_dirtrunc: bad offset")); 749 block = howmany(offset, DIRBLKSIZ); 750 /* 751 * If the directory shrinks to less than 1/8 of dh_nblk blocks 752 * (about 20% of its original size due to the 50% extra added in 753 * ufsdirhash_build) then free it, and let the caller rebuild 754 * if necessary. 755 */ 756 if (block < dh->dh_nblk / 8 && dh->dh_narrays > 1) { 757 mtx_unlock(&dh->dh_mtx); 758 ufsdirhash_free(ip); 759 return; 760 } 761 762 /* 763 * Remove any `first free' information pertaining to the 764 * truncated blocks. All blocks we're removing should be 765 * completely unused. 766 */ 767 if (dh->dh_firstfree[DH_NFSTATS] >= block) 768 dh->dh_firstfree[DH_NFSTATS] = -1; 769 for (i = block; i < dh->dh_dirblks; i++) 770 if (dh->dh_blkfree[i] != DIRBLKSIZ / DIRALIGN) 771 panic("ufsdirhash_dirtrunc: blocks in use"); 772 for (i = 0; i < DH_NFSTATS; i++) 773 if (dh->dh_firstfree[i] >= block) 774 panic("ufsdirhash_dirtrunc: first free corrupt"); 775 dh->dh_dirblks = block; 776 mtx_unlock(&dh->dh_mtx); 777} 778 779/* 780 * Debugging function to check that the dirhash information about 781 * a directory block matches its actual contents. Panics if a mismatch 782 * is detected. 783 * 784 * On entry, `buf' should point to the start of an in-core 785 * DIRBLKSIZ-sized directory block, and `offset' should contain the 786 * offset from the start of the directory of that block. 787 */ 788void 789ufsdirhash_checkblock(struct inode *ip, char *buf, doff_t offset) 790{ 791 struct dirhash *dh; 792 struct direct *dp; 793 int block, ffslot, i, nfree; 794 795 if (!ufs_dirhashcheck) 796 return; 797 if ((dh = ip->i_dirhash) == NULL) 798 return; 799 mtx_lock(&dh->dh_mtx); 800 if (dh->dh_hash == NULL) { 801 mtx_unlock(&dh->dh_mtx); 802 ufsdirhash_free(ip); 803 return; 804 } 805 806 block = offset / DIRBLKSIZ; 807 if ((offset & (DIRBLKSIZ - 1)) != 0 || block >= dh->dh_dirblks) 808 panic("ufsdirhash_checkblock: bad offset"); 809 810 nfree = 0; 811 for (i = 0; i < DIRBLKSIZ; i += dp->d_reclen) { 812 dp = (struct direct *)(buf + i); 813 if (dp->d_reclen == 0 || i + dp->d_reclen > DIRBLKSIZ) 814 panic("ufsdirhash_checkblock: bad dir"); 815 816 if (dp->d_ino == 0) { 817 if (i != 0) 818 panic("ufsdirhash_checkblock: bad dir inode"); 819 nfree += dp->d_reclen; 820 continue; 821 } 822 823 /* Check that the entry exists (will panic if it doesn't). */ 824 ufsdirhash_findslot(dh, dp->d_name, dp->d_namlen, offset + i); 825 826 nfree += dp->d_reclen - DIRSIZ(0, dp); 827 } 828 if (i != DIRBLKSIZ) 829 panic("ufsdirhash_checkblock: bad dir end"); 830 831 if (dh->dh_blkfree[block] * DIRALIGN != nfree) 832 panic("ufsdirhash_checkblock: bad free count"); 833 834 ffslot = nfree / DIRALIGN; 835 if (ffslot > DH_NFSTATS) 836 ffslot = DH_NFSTATS; 837 for (i = 0; i <= DH_NFSTATS; i++) 838 if (dh->dh_firstfree[i] == block && i != ffslot) 839 panic("ufsdirhash_checkblock: bad first-free"); 840 mtx_unlock(&dh->dh_mtx); 841} 842 843/* 844 * Hash the specified filename into a dirhash slot. 845 */ 846static int 847ufsdirhash_hash(struct dirhash *dh, char *name, int namelen) 848{ 849 return (fnv_32_buf(name, namelen, FNV1_32_INIT) % dh->dh_hlen); 850} 851 852/* 853 * Adjust the number of free bytes in the block containing `offset' 854 * by the value specified by `diff'. 855 * 856 * The caller must ensure we have exclusive access to `dh'; normally 857 * that means that dh_mtx should be held, but this is also called 858 * from ufsdirhash_build() where exclusive access can be assumed. 859 */ 860static void 861ufsdirhash_adjfree(struct dirhash *dh, doff_t offset, int diff) 862{ 863 int block, i, nfidx, ofidx; 864 865 /* Update the per-block summary info. */ 866 block = offset / DIRBLKSIZ; 867 KASSERT(block < dh->dh_nblk && block < dh->dh_dirblks, 868 ("dirhash bad offset")); 869 ofidx = dh->dh_blkfree[block]; 870 if (ofidx > DH_NFSTATS) 871 ofidx = DH_NFSTATS; 872 dh->dh_blkfree[block] = (int)dh->dh_blkfree[block] + (diff / DIRALIGN); 873 nfidx = dh->dh_blkfree[block]; 874 if (nfidx > DH_NFSTATS) 875 nfidx = DH_NFSTATS; 876 877 /* Update the `first free' list if necessary. */ 878 if (ofidx != nfidx) { 879 /* If removing, scan forward for the next block. */ 880 if (dh->dh_firstfree[ofidx] == block) { 881 for (i = block + 1; i < dh->dh_dirblks; i++) 882 if (dh->dh_blkfree[i] == ofidx) 883 break; 884 dh->dh_firstfree[ofidx] = (i < dh->dh_dirblks) ? i : -1; 885 } 886 887 /* Make this the new `first free' if necessary */ 888 if (dh->dh_firstfree[nfidx] > block || 889 dh->dh_firstfree[nfidx] == -1) 890 dh->dh_firstfree[nfidx] = block; 891 } 892} 893 894/* 895 * Find the specified name which should have the specified offset. 896 * Returns a slot number, and panics on failure. 897 * 898 * `dh' must be locked on entry and remains so on return. 899 */ 900static int 901ufsdirhash_findslot(struct dirhash *dh, char *name, int namelen, doff_t offset) 902{ 903 int slot; 904 905 mtx_assert(&dh->dh_mtx, MA_OWNED); 906 907 /* Find the entry. */ 908 KASSERT(dh->dh_hused < dh->dh_hlen, ("dirhash find full")); 909 slot = ufsdirhash_hash(dh, name, namelen); 910 while (DH_ENTRY(dh, slot) != offset && 911 DH_ENTRY(dh, slot) != DIRHASH_EMPTY) 912 slot = WRAPINCR(slot, dh->dh_hlen); 913 if (DH_ENTRY(dh, slot) != offset) 914 panic("ufsdirhash_findslot: '%.*s' not found", namelen, name); 915 916 return (slot); 917} 918 919/* 920 * Remove the entry corresponding to the specified slot from the hash array. 921 * 922 * `dh' must be locked on entry and remains so on return. 923 */ 924static void 925ufsdirhash_delslot(struct dirhash *dh, int slot) 926{ 927 int i; 928 929 mtx_assert(&dh->dh_mtx, MA_OWNED); 930 931 /* Mark the entry as deleted. */ 932 DH_ENTRY(dh, slot) = DIRHASH_DEL; 933 934 /* If this is the end of a chain of DIRHASH_DEL slots, remove them. */ 935 for (i = slot; DH_ENTRY(dh, i) == DIRHASH_DEL; ) 936 i = WRAPINCR(i, dh->dh_hlen); 937 if (DH_ENTRY(dh, i) == DIRHASH_EMPTY) { 938 for (i = slot; DH_ENTRY(dh, i) == DIRHASH_DEL; ) { 939 DH_ENTRY(dh, i) = DIRHASH_EMPTY; 940 dh->dh_hused--; 941 i = WRAPINCR(i, dh->dh_hlen); 942 } 943 KASSERT(dh->dh_hused >= 0, ("ufsdirhash_delslot neg hlen")); 944 } 945} 946 947/* 948 * Given a directory entry and its offset, find the offset of the 949 * previous entry in the same DIRBLKSIZ-sized block. Returns an 950 * offset, or -1 if there is no previous entry in the block or some 951 * other problem occurred. 952 */ 953static doff_t 954ufsdirhash_getprev(struct direct *dirp, doff_t offset) 955{ 956 struct direct *dp; 957 char *blkbuf; 958 doff_t blkoff, prevoff; 959 int entrypos, i; 960 961 blkoff = offset & ~(DIRBLKSIZ - 1); /* offset of start of block */ 962 entrypos = offset & (DIRBLKSIZ - 1); /* entry relative to block */ 963 blkbuf = (char *)dirp - entrypos; 964 prevoff = blkoff; 965 966 /* If `offset' is the start of a block, there is no previous entry. */ 967 if (entrypos == 0) 968 return (-1); 969 970 /* Scan from the start of the block until we get to the entry. */ 971 for (i = 0; i < entrypos; i += dp->d_reclen) { 972 dp = (struct direct *)(blkbuf + i); 973 if (dp->d_reclen == 0 || i + dp->d_reclen > entrypos) 974 return (-1); /* Corrupted directory. */ 975 prevoff = blkoff + i; 976 } 977 return (prevoff); 978} 979 980/* 981 * Try to free up `wanted' bytes by stealing memory from existing 982 * dirhashes. Returns zero with ufsdirhash_mtx locked if successful. 983 */ 984static int 985ufsdirhash_recycle(int wanted) 986{ 987 struct dirhash *dh; 988 doff_t **hash; 989 u_int8_t *blkfree; 990 int i, mem, narrays; 991 992 mtx_lock(&ufsdirhash_mtx); 993 while (wanted + ufs_dirhashmem > ufs_dirhashmaxmem) { 994 /* Find a dirhash, and lock it. */ 995 if ((dh = TAILQ_FIRST(&ufsdirhash_list)) == NULL) { 996 mtx_unlock(&ufsdirhash_mtx); 997 return (-1); 998 } 999 mtx_lock(&dh->dh_mtx); 1000 KASSERT(dh->dh_hash != NULL, ("dirhash: NULL hash on list")); 1001 1002 /* Decrement the score; only recycle if it becomes zero. */ 1003 if (--dh->dh_score > 0) { 1004 mtx_unlock(&dh->dh_mtx); 1005 mtx_unlock(&ufsdirhash_mtx); 1006 return (-1); 1007 } 1008 1009 /* Remove it from the list and detach its memory. */ 1010 TAILQ_REMOVE(&ufsdirhash_list, dh, dh_list); 1011 dh->dh_onlist = 0; 1012 hash = dh->dh_hash; 1013 dh->dh_hash = NULL; 1014 blkfree = dh->dh_blkfree; 1015 dh->dh_blkfree = NULL; 1016 narrays = dh->dh_narrays; 1017 mem = narrays * sizeof(*dh->dh_hash) + 1018 narrays * DH_NBLKOFF * sizeof(**dh->dh_hash) + 1019 dh->dh_nblk * sizeof(*dh->dh_blkfree); 1020 1021 /* Unlock everything, free the detached memory. */ 1022 mtx_unlock(&dh->dh_mtx); 1023 mtx_unlock(&ufsdirhash_mtx); 1024 for (i = 0; i < narrays; i++) 1025 zfree(ufsdirhash_zone, hash[i]); 1026 FREE(hash, M_DIRHASH); 1027 FREE(blkfree, M_DIRHASH); 1028 1029 /* Account for the returned memory, and repeat if necessary. */ 1030 mtx_lock(&ufsdirhash_mtx); 1031 ufs_dirhashmem -= mem; 1032 } 1033 /* Success; return with ufsdirhash_mtx locked. */ 1034 return (0); 1035} 1036 1037 1038static void 1039ufsdirhash_init() 1040{ 1041 ufsdirhash_zone = zinit("DIRHASH", DH_NBLKOFF * sizeof(daddr_t), 0, 1042 0, 1); 1043 mtx_init(&ufsdirhash_mtx, "dirhash list", MTX_DEF); 1044 TAILQ_INIT(&ufsdirhash_list); 1045} 1046SYSINIT(ufsdirhash, SI_SUB_PSEUDO, SI_ORDER_ANY, ufsdirhash_init, NULL) 1047 1048 1049#endif /* UFS_DIRHASH */ 1050