ufs_dirhash.c revision 187474
1310490Scy/*- 238494Sobrien * Copyright (c) 2001, 2002 Ian Dowse. All rights reserved. 338494Sobrien * 438494Sobrien * Redistribution and use in source and binary forms, with or without 538494Sobrien * modification, are permitted provided that the following conditions 638494Sobrien * are met: 738494Sobrien * 1. Redistributions of source code must retain the above copyright 838494Sobrien * notice, this list of conditions and the following disclaimer. 938494Sobrien * 2. Redistributions in binary form must reproduce the above copyright 1038494Sobrien * notice, this list of conditions and the following disclaimer in the 1138494Sobrien * documentation and/or other materials provided with the distribution. 1238494Sobrien * 1338494Sobrien * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 1438494Sobrien * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1538494Sobrien * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 1638494Sobrien * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 1738494Sobrien * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18310490Scy * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 1938494Sobrien * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2038494Sobrien * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2138494Sobrien * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2238494Sobrien * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2338494Sobrien * SUCH DAMAGE. 2438494Sobrien */ 2538494Sobrien 2638494Sobrien/* 2738494Sobrien * This implements a hash-based lookup scheme for UFS directories. 2838494Sobrien */ 2938494Sobrien 3038494Sobrien#include <sys/cdefs.h> 3138494Sobrien__FBSDID("$FreeBSD: head/sys/ufs/ufs/ufs_dirhash.c 187474 2009-01-20 16:35:34Z jhb $"); 3238494Sobrien 33#include "opt_ufs.h" 34 35#ifdef UFS_DIRHASH 36 37#include <sys/param.h> 38#include <sys/systm.h> 39#include <sys/kernel.h> 40#include <sys/lock.h> 41#include <sys/mutex.h> 42#include <sys/malloc.h> 43#include <sys/fnv_hash.h> 44#include <sys/proc.h> 45#include <sys/bio.h> 46#include <sys/buf.h> 47#include <sys/vnode.h> 48#include <sys/mount.h> 49#include <sys/refcount.h> 50#include <sys/sysctl.h> 51#include <sys/sx.h> 52#include <vm/uma.h> 53 54#include <ufs/ufs/quota.h> 55#include <ufs/ufs/inode.h> 56#include <ufs/ufs/dir.h> 57#include <ufs/ufs/dirhash.h> 58#include <ufs/ufs/extattr.h> 59#include <ufs/ufs/ufsmount.h> 60#include <ufs/ufs/ufs_extern.h> 61 62#define WRAPINCR(val, limit) (((val) + 1 == (limit)) ? 0 : ((val) + 1)) 63#define WRAPDECR(val, limit) (((val) == 0) ? ((limit) - 1) : ((val) - 1)) 64#define OFSFMT(vp) ((vp)->v_mount->mnt_maxsymlinklen <= 0) 65#define BLKFREE2IDX(n) ((n) > DH_NFSTATS ? DH_NFSTATS : (n)) 66 67static MALLOC_DEFINE(M_DIRHASH, "ufs_dirhash", "UFS directory hash tables"); 68 69static SYSCTL_NODE(_vfs, OID_AUTO, ufs, CTLFLAG_RD, 0, "UFS filesystem"); 70 71static int ufs_mindirhashsize = DIRBLKSIZ * 5; 72SYSCTL_INT(_vfs_ufs, OID_AUTO, dirhash_minsize, CTLFLAG_RW, 73 &ufs_mindirhashsize, 74 0, "minimum directory size in bytes for which to use hashed lookup"); 75static int ufs_dirhashmaxmem = 2 * 1024 * 1024; 76SYSCTL_INT(_vfs_ufs, OID_AUTO, dirhash_maxmem, CTLFLAG_RW, &ufs_dirhashmaxmem, 77 0, "maximum allowed dirhash memory usage"); 78static int ufs_dirhashmem; 79SYSCTL_INT(_vfs_ufs, OID_AUTO, dirhash_mem, CTLFLAG_RD, &ufs_dirhashmem, 80 0, "current dirhash memory usage"); 81static int ufs_dirhashcheck = 0; 82SYSCTL_INT(_vfs_ufs, OID_AUTO, dirhash_docheck, CTLFLAG_RW, &ufs_dirhashcheck, 83 0, "enable extra sanity tests"); 84 85 86static int ufsdirhash_hash(struct dirhash *dh, char *name, int namelen); 87static void ufsdirhash_adjfree(struct dirhash *dh, doff_t offset, int diff); 88static void ufsdirhash_delslot(struct dirhash *dh, int slot); 89static int ufsdirhash_findslot(struct dirhash *dh, char *name, int namelen, 90 doff_t offset); 91static doff_t ufsdirhash_getprev(struct direct *dp, doff_t offset); 92static int ufsdirhash_recycle(int wanted); 93static void ufsdirhash_free_locked(struct inode *ip); 94 95static uma_zone_t ufsdirhash_zone; 96 97#define DIRHASHLIST_LOCK() mtx_lock(&ufsdirhash_mtx) 98#define DIRHASHLIST_UNLOCK() mtx_unlock(&ufsdirhash_mtx) 99#define DIRHASH_BLKALLOC_WAITOK() uma_zalloc(ufsdirhash_zone, M_WAITOK) 100#define DIRHASH_BLKFREE(ptr) uma_zfree(ufsdirhash_zone, (ptr)) 101#define DIRHASH_ASSERT_LOCKED(dh) \ 102 sx_assert(&(dh)->dh_lock, SA_LOCKED) 103 104/* Dirhash list; recently-used entries are near the tail. */ 105static TAILQ_HEAD(, dirhash) ufsdirhash_list; 106 107/* Protects: ufsdirhash_list, `dh_list' field, ufs_dirhashmem. */ 108static struct mtx ufsdirhash_mtx; 109 110/* 111 * Locking: 112 * 113 * The relationship between inode and dirhash is protected either by an 114 * exclusive vnode lock or the vnode interlock where a shared vnode lock 115 * may be used. The dirhash_mtx is acquired after the dirhash lock. To 116 * handle teardown races, code wishing to lock the dirhash for an inode 117 * when using a shared vnode lock must obtain a private reference on the 118 * dirhash while holding the vnode interlock. They can drop it once they 119 * have obtained the dirhash lock and verified that the dirhash wasn't 120 * recycled while they waited for the dirhash lock. 121 * 122 * ufsdirhash_build() acquires a shared lock on the dirhash when it is 123 * successful. This lock is released after a call to ufsdirhash_lookup(). 124 * 125 * Functions requiring exclusive access use ufsdirhash_acquire() which may 126 * free a dirhash structure that was recycled by ufsdirhash_recycle(). 127 * 128 * The dirhash lock may be held across io operations. 129 * 130 * WITNESS reports a lock order reversal between the "bufwait" lock 131 * and the "dirhash" lock. However, this specific reversal will not 132 * cause a deadlock. To get a deadlock, one would have to lock a 133 * buffer followed by the dirhash while a second thread locked a 134 * buffer while holding the dirhash lock. The second order can happen 135 * under a shared or exclusive vnode lock for the associated directory 136 * in lookup(). The first order, however, can only happen under an 137 * exclusive vnode lock (e.g. unlink(), rename(), etc.). Thus, for 138 * a thread to be doing a "bufwait" -> "dirhash" order, it has to hold 139 * an exclusive vnode lock. That exclusive vnode lock will prevent 140 * any other threads from doing a "dirhash" -> "bufwait" order. 141 */ 142 143static void 144ufsdirhash_hold(struct dirhash *dh) 145{ 146 147 refcount_acquire(&dh->dh_refcount); 148} 149 150static void 151ufsdirhash_drop(struct dirhash *dh) 152{ 153 154 if (refcount_release(&dh->dh_refcount)) { 155 sx_destroy(&dh->dh_lock); 156 free(dh, M_DIRHASH); 157 } 158} 159 160/* 161 * Release the lock on a dirhash. 162 */ 163static void 164ufsdirhash_release(struct dirhash *dh) 165{ 166 167 sx_unlock(&dh->dh_lock); 168} 169 170/* 171 * Either acquire an existing hash locked shared or create a new hash and 172 * return it exclusively locked. May return NULL if the allocation fails. 173 * 174 * The vnode interlock is used to protect the i_dirhash pointer from 175 * simultaneous access while only a shared vnode lock is held. 176 */ 177static struct dirhash * 178ufsdirhash_create(struct inode *ip) 179{ 180 struct dirhash *ndh; 181 struct dirhash *dh; 182 struct vnode *vp; 183 int error; 184 185 error = 0; 186 ndh = dh = NULL; 187 vp = ip->i_vnode; 188 for (;;) { 189 /* Racy check for i_dirhash to prefetch a dirhash structure. */ 190 if (ip->i_dirhash == NULL && ndh == NULL) { 191 ndh = malloc(sizeof *dh, M_DIRHASH, 192 M_NOWAIT | M_ZERO); 193 if (ndh == NULL) 194 return (NULL); 195 refcount_init(&ndh->dh_refcount, 1); 196 197 /* 198 * The DUPOK is to prevent warnings from the 199 * sx_slock() a few lines down which is safe 200 * since the duplicate lock in that case is 201 * the one for this dirhash we are creating 202 * now which has no external references until 203 * after this function returns. 204 */ 205 sx_init_flags(&ndh->dh_lock, "dirhash", SX_DUPOK); 206 sx_xlock(&ndh->dh_lock); 207 } 208 /* 209 * Check i_dirhash. If it's NULL just try to use a 210 * preallocated structure. If none exists loop and try again. 211 */ 212 VI_LOCK(vp); 213 dh = ip->i_dirhash; 214 if (dh == NULL) { 215 ip->i_dirhash = ndh; 216 VI_UNLOCK(vp); 217 if (ndh == NULL) 218 continue; 219 return (ndh); 220 } 221 ufsdirhash_hold(dh); 222 VI_UNLOCK(vp); 223 224 /* Acquire a shared lock on existing hashes. */ 225 sx_slock(&dh->dh_lock); 226 227 /* The hash could've been recycled while we were waiting. */ 228 VI_LOCK(vp); 229 if (ip->i_dirhash != dh) { 230 VI_UNLOCK(vp); 231 ufsdirhash_release(dh); 232 ufsdirhash_drop(dh); 233 continue; 234 } 235 VI_UNLOCK(vp); 236 ufsdirhash_drop(dh); 237 238 /* If the hash is still valid we've succeeded. */ 239 if (dh->dh_hash != NULL) 240 break; 241 /* 242 * If the hash is NULL it has been recycled. Try to upgrade 243 * so we can recreate it. If we fail the upgrade, drop our 244 * lock and try again. 245 */ 246 if (sx_try_upgrade(&dh->dh_lock)) 247 break; 248 sx_sunlock(&dh->dh_lock); 249 } 250 /* Free the preallocated structure if it was not necessary. */ 251 if (ndh) { 252 ufsdirhash_release(ndh); 253 ufsdirhash_drop(ndh); 254 } 255 return (dh); 256} 257 258/* 259 * Acquire an exclusive lock on an existing hash. Requires an exclusive 260 * vnode lock to protect the i_dirhash pointer. hashes that have been 261 * recycled are reclaimed here and NULL is returned. 262 */ 263static struct dirhash * 264ufsdirhash_acquire(struct inode *ip) 265{ 266 struct dirhash *dh; 267 struct vnode *vp; 268 269 ASSERT_VOP_ELOCKED(ip->i_vnode, __FUNCTION__); 270 271 vp = ip->i_vnode; 272 dh = ip->i_dirhash; 273 if (dh == NULL) 274 return (NULL); 275 sx_xlock(&dh->dh_lock); 276 if (dh->dh_hash != NULL) 277 return (dh); 278 ufsdirhash_free_locked(ip); 279 return (NULL); 280} 281 282/* 283 * Acquire exclusively and free the hash pointed to by ip. Works with a 284 * shared or exclusive vnode lock. 285 */ 286void 287ufsdirhash_free(struct inode *ip) 288{ 289 struct dirhash *dh; 290 struct vnode *vp; 291 292 vp = ip->i_vnode; 293 for (;;) { 294 /* Grab a reference on this inode's dirhash if it has one. */ 295 VI_LOCK(vp); 296 dh = ip->i_dirhash; 297 if (dh == NULL) { 298 VI_UNLOCK(vp); 299 return; 300 } 301 ufsdirhash_hold(dh); 302 VI_UNLOCK(vp); 303 304 /* Exclusively lock the dirhash. */ 305 sx_xlock(&dh->dh_lock); 306 307 /* If this dirhash still belongs to this inode, then free it. */ 308 VI_LOCK(vp); 309 if (ip->i_dirhash == dh) { 310 VI_UNLOCK(vp); 311 ufsdirhash_drop(dh); 312 break; 313 } 314 VI_UNLOCK(vp); 315 316 /* 317 * This inode's dirhash has changed while we were 318 * waiting for the dirhash lock, so try again. 319 */ 320 ufsdirhash_release(dh); 321 ufsdirhash_drop(dh); 322 } 323 ufsdirhash_free_locked(ip); 324} 325 326/* 327 * Attempt to build up a hash table for the directory contents in 328 * inode 'ip'. Returns 0 on success, or -1 of the operation failed. 329 */ 330int 331ufsdirhash_build(struct inode *ip) 332{ 333 struct dirhash *dh; 334 struct buf *bp = NULL; 335 struct direct *ep; 336 struct vnode *vp; 337 doff_t bmask, pos; 338 int dirblocks, i, j, memreqd, nblocks, narrays, nslots, slot; 339 340 /* Take care of a decreased sysctl value. */ 341 while (ufs_dirhashmem > ufs_dirhashmaxmem) 342 if (ufsdirhash_recycle(0) != 0) 343 return (-1); 344 345 /* Check if we can/should use dirhash. */ 346 if (ip->i_size < ufs_mindirhashsize || OFSFMT(ip->i_vnode) || 347 ip->i_effnlink == 0) { 348 if (ip->i_dirhash) 349 ufsdirhash_free(ip); 350 return (-1); 351 } 352 dh = ufsdirhash_create(ip); 353 if (dh == NULL) 354 return (-1); 355 if (dh->dh_hash != NULL) 356 return (0); 357 358 vp = ip->i_vnode; 359 /* Allocate 50% more entries than this dir size could ever need. */ 360 KASSERT(ip->i_size >= DIRBLKSIZ, ("ufsdirhash_build size")); 361 nslots = ip->i_size / DIRECTSIZ(1); 362 nslots = (nslots * 3 + 1) / 2; 363 narrays = howmany(nslots, DH_NBLKOFF); 364 nslots = narrays * DH_NBLKOFF; 365 dirblocks = howmany(ip->i_size, DIRBLKSIZ); 366 nblocks = (dirblocks * 3 + 1) / 2; 367 memreqd = sizeof(*dh) + narrays * sizeof(*dh->dh_hash) + 368 narrays * DH_NBLKOFF * sizeof(**dh->dh_hash) + 369 nblocks * sizeof(*dh->dh_blkfree); 370 DIRHASHLIST_LOCK(); 371 if (memreqd + ufs_dirhashmem > ufs_dirhashmaxmem) { 372 DIRHASHLIST_UNLOCK(); 373 if (memreqd > ufs_dirhashmaxmem / 2) 374 goto fail; 375 /* Try to free some space. */ 376 if (ufsdirhash_recycle(memreqd) != 0) 377 goto fail; 378 /* Enough was freed, and list has been locked. */ 379 } 380 ufs_dirhashmem += memreqd; 381 DIRHASHLIST_UNLOCK(); 382 383 /* Initialise the hash table and block statistics. */ 384 dh->dh_memreq = memreqd; 385 dh->dh_narrays = narrays; 386 dh->dh_hlen = nslots; 387 dh->dh_nblk = nblocks; 388 dh->dh_dirblks = dirblocks; 389 for (i = 0; i < DH_NFSTATS; i++) 390 dh->dh_firstfree[i] = -1; 391 dh->dh_firstfree[DH_NFSTATS] = 0; 392 dh->dh_hused = 0; 393 dh->dh_seqopt = 0; 394 dh->dh_seqoff = 0; 395 dh->dh_score = DH_SCOREINIT; 396 397 /* 398 * Use non-blocking mallocs so that we will revert to a linear 399 * lookup on failure rather than potentially blocking forever. 400 */ 401 dh->dh_hash = malloc(narrays * sizeof(dh->dh_hash[0]), 402 M_DIRHASH, M_NOWAIT | M_ZERO); 403 if (dh->dh_hash == NULL) 404 goto fail; 405 dh->dh_blkfree = malloc(nblocks * sizeof(dh->dh_blkfree[0]), 406 M_DIRHASH, M_NOWAIT); 407 if (dh->dh_blkfree == NULL) 408 goto fail; 409 for (i = 0; i < narrays; i++) { 410 if ((dh->dh_hash[i] = DIRHASH_BLKALLOC_WAITOK()) == NULL) 411 goto fail; 412 for (j = 0; j < DH_NBLKOFF; j++) 413 dh->dh_hash[i][j] = DIRHASH_EMPTY; 414 } 415 for (i = 0; i < dirblocks; i++) 416 dh->dh_blkfree[i] = DIRBLKSIZ / DIRALIGN; 417 bmask = VFSTOUFS(vp->v_mount)->um_mountp->mnt_stat.f_iosize - 1; 418 pos = 0; 419 while (pos < ip->i_size) { 420 /* If necessary, get the next directory block. */ 421 if ((pos & bmask) == 0) { 422 if (bp != NULL) 423 brelse(bp); 424 if (UFS_BLKATOFF(vp, (off_t)pos, NULL, &bp) != 0) 425 goto fail; 426 } 427 428 /* Add this entry to the hash. */ 429 ep = (struct direct *)((char *)bp->b_data + (pos & bmask)); 430 if (ep->d_reclen == 0 || ep->d_reclen > 431 DIRBLKSIZ - (pos & (DIRBLKSIZ - 1))) { 432 /* Corrupted directory. */ 433 brelse(bp); 434 goto fail; 435 } 436 if (ep->d_ino != 0) { 437 /* Add the entry (simplified ufsdirhash_add). */ 438 slot = ufsdirhash_hash(dh, ep->d_name, ep->d_namlen); 439 while (DH_ENTRY(dh, slot) != DIRHASH_EMPTY) 440 slot = WRAPINCR(slot, dh->dh_hlen); 441 dh->dh_hused++; 442 DH_ENTRY(dh, slot) = pos; 443 ufsdirhash_adjfree(dh, pos, -DIRSIZ(0, ep)); 444 } 445 pos += ep->d_reclen; 446 } 447 448 if (bp != NULL) 449 brelse(bp); 450 DIRHASHLIST_LOCK(); 451 TAILQ_INSERT_TAIL(&ufsdirhash_list, dh, dh_list); 452 dh->dh_onlist = 1; 453 DIRHASHLIST_UNLOCK(); 454 sx_downgrade(&dh->dh_lock); 455 return (0); 456 457fail: 458 ufsdirhash_free_locked(ip); 459 return (-1); 460} 461 462/* 463 * Free any hash table associated with inode 'ip'. 464 */ 465static void 466ufsdirhash_free_locked(struct inode *ip) 467{ 468 struct dirhash *dh; 469 struct vnode *vp; 470 int i; 471 472 DIRHASH_ASSERT_LOCKED(ip->i_dirhash); 473 474 /* 475 * Clear the pointer in the inode to prevent new threads from 476 * finding the dead structure. 477 */ 478 vp = ip->i_vnode; 479 VI_LOCK(vp); 480 dh = ip->i_dirhash; 481 ip->i_dirhash = NULL; 482 VI_UNLOCK(vp); 483 484 /* 485 * Remove the hash from the list since we are going to free its 486 * memory. 487 */ 488 DIRHASHLIST_LOCK(); 489 if (dh->dh_onlist) 490 TAILQ_REMOVE(&ufsdirhash_list, dh, dh_list); 491 ufs_dirhashmem -= dh->dh_memreq; 492 DIRHASHLIST_UNLOCK(); 493 494 /* 495 * At this point, any waiters for the lock should hold their 496 * own reference on the dirhash structure. They will drop 497 * that reference once they grab the vnode interlock and see 498 * that ip->i_dirhash is NULL. 499 */ 500 sx_xunlock(&dh->dh_lock); 501 502 /* 503 * Handle partially recycled as well as fully constructed hashes. 504 */ 505 if (dh->dh_hash != NULL) { 506 for (i = 0; i < dh->dh_narrays; i++) 507 if (dh->dh_hash[i] != NULL) 508 DIRHASH_BLKFREE(dh->dh_hash[i]); 509 free(dh->dh_hash, M_DIRHASH); 510 if (dh->dh_blkfree != NULL) 511 free(dh->dh_blkfree, M_DIRHASH); 512 } 513 514 /* 515 * Drop the inode's reference to the data structure. 516 */ 517 ufsdirhash_drop(dh); 518} 519 520/* 521 * Find the offset of the specified name within the given inode. 522 * Returns 0 on success, ENOENT if the entry does not exist, or 523 * EJUSTRETURN if the caller should revert to a linear search. 524 * 525 * If successful, the directory offset is stored in *offp, and a 526 * pointer to a struct buf containing the entry is stored in *bpp. If 527 * prevoffp is non-NULL, the offset of the previous entry within 528 * the DIRBLKSIZ-sized block is stored in *prevoffp (if the entry 529 * is the first in a block, the start of the block is used). 530 * 531 * Must be called with the hash locked. Returns with the hash unlocked. 532 */ 533int 534ufsdirhash_lookup(struct inode *ip, char *name, int namelen, doff_t *offp, 535 struct buf **bpp, doff_t *prevoffp) 536{ 537 struct dirhash *dh, *dh_next; 538 struct direct *dp; 539 struct vnode *vp; 540 struct buf *bp; 541 doff_t blkoff, bmask, offset, prevoff; 542 int i, slot; 543 int error; 544 545 dh = ip->i_dirhash; 546 KASSERT(dh != NULL && dh->dh_hash != NULL, 547 ("ufsdirhash_lookup: Invalid dirhash %p\n", dh)); 548 DIRHASH_ASSERT_LOCKED(dh); 549 /* 550 * Move this dirhash towards the end of the list if it has a 551 * score higher than the next entry, and acquire the dh_lock. 552 */ 553 DIRHASHLIST_LOCK(); 554 if (TAILQ_NEXT(dh, dh_list) != NULL) { 555 /* 556 * If the new score will be greater than that of the next 557 * entry, then move this entry past it. With both mutexes 558 * held, dh_next won't go away, but its dh_score could 559 * change; that's not important since it is just a hint. 560 */ 561 if ((dh_next = TAILQ_NEXT(dh, dh_list)) != NULL && 562 dh->dh_score >= dh_next->dh_score) { 563 KASSERT(dh->dh_onlist, ("dirhash: not on list")); 564 TAILQ_REMOVE(&ufsdirhash_list, dh, dh_list); 565 TAILQ_INSERT_AFTER(&ufsdirhash_list, dh_next, dh, 566 dh_list); 567 } 568 } 569 /* Update the score. */ 570 if (dh->dh_score < DH_SCOREMAX) 571 dh->dh_score++; 572 DIRHASHLIST_UNLOCK(); 573 574 vp = ip->i_vnode; 575 bmask = VFSTOUFS(vp->v_mount)->um_mountp->mnt_stat.f_iosize - 1; 576 blkoff = -1; 577 bp = NULL; 578restart: 579 slot = ufsdirhash_hash(dh, name, namelen); 580 581 if (dh->dh_seqopt) { 582 /* 583 * Sequential access optimisation. dh_seqoff contains the 584 * offset of the directory entry immediately following 585 * the last entry that was looked up. Check if this offset 586 * appears in the hash chain for the name we are looking for. 587 */ 588 for (i = slot; (offset = DH_ENTRY(dh, i)) != DIRHASH_EMPTY; 589 i = WRAPINCR(i, dh->dh_hlen)) 590 if (offset == dh->dh_seqoff) 591 break; 592 if (offset == dh->dh_seqoff) { 593 /* 594 * We found an entry with the expected offset. This 595 * is probably the entry we want, but if not, the 596 * code below will turn off seqopt and retry. 597 */ 598 slot = i; 599 } else 600 dh->dh_seqopt = 0; 601 } 602 603 for (; (offset = DH_ENTRY(dh, slot)) != DIRHASH_EMPTY; 604 slot = WRAPINCR(slot, dh->dh_hlen)) { 605 if (offset == DIRHASH_DEL) 606 continue; 607 if (offset < 0 || offset >= ip->i_size) 608 panic("ufsdirhash_lookup: bad offset in hash array"); 609 if ((offset & ~bmask) != blkoff) { 610 if (bp != NULL) 611 brelse(bp); 612 blkoff = offset & ~bmask; 613 if (UFS_BLKATOFF(vp, (off_t)blkoff, NULL, &bp) != 0) { 614 error = EJUSTRETURN; 615 goto fail; 616 } 617 } 618 dp = (struct direct *)(bp->b_data + (offset & bmask)); 619 if (dp->d_reclen == 0 || dp->d_reclen > 620 DIRBLKSIZ - (offset & (DIRBLKSIZ - 1))) { 621 /* Corrupted directory. */ 622 error = EJUSTRETURN; 623 goto fail; 624 } 625 if (dp->d_namlen == namelen && 626 bcmp(dp->d_name, name, namelen) == 0) { 627 /* Found. Get the prev offset if needed. */ 628 if (prevoffp != NULL) { 629 if (offset & (DIRBLKSIZ - 1)) { 630 prevoff = ufsdirhash_getprev(dp, 631 offset); 632 if (prevoff == -1) { 633 error = EJUSTRETURN; 634 goto fail; 635 } 636 } else 637 prevoff = offset; 638 *prevoffp = prevoff; 639 } 640 641 /* Check for sequential access, and update offset. */ 642 if (dh->dh_seqopt == 0 && dh->dh_seqoff == offset) 643 dh->dh_seqopt = 1; 644 dh->dh_seqoff = offset + DIRSIZ(0, dp); 645 *bpp = bp; 646 *offp = offset; 647 ufsdirhash_release(dh); 648 return (0); 649 } 650 651 /* 652 * When the name doesn't match in the seqopt case, go back 653 * and search normally. 654 */ 655 if (dh->dh_seqopt) { 656 dh->dh_seqopt = 0; 657 goto restart; 658 } 659 } 660 error = ENOENT; 661fail: 662 ufsdirhash_release(dh); 663 if (bp != NULL) 664 brelse(bp); 665 return (error); 666} 667 668/* 669 * Find a directory block with room for 'slotneeded' bytes. Returns 670 * the offset of the directory entry that begins the free space. 671 * This will either be the offset of an existing entry that has free 672 * space at the end, or the offset of an entry with d_ino == 0 at 673 * the start of a DIRBLKSIZ block. 674 * 675 * To use the space, the caller may need to compact existing entries in 676 * the directory. The total number of bytes in all of the entries involved 677 * in the compaction is stored in *slotsize. In other words, all of 678 * the entries that must be compacted are exactly contained in the 679 * region beginning at the returned offset and spanning *slotsize bytes. 680 * 681 * Returns -1 if no space was found, indicating that the directory 682 * must be extended. 683 */ 684doff_t 685ufsdirhash_findfree(struct inode *ip, int slotneeded, int *slotsize) 686{ 687 struct direct *dp; 688 struct dirhash *dh; 689 struct buf *bp; 690 doff_t pos, slotstart; 691 int dirblock, error, freebytes, i; 692 693 dh = ip->i_dirhash; 694 KASSERT(dh != NULL && dh->dh_hash != NULL, 695 ("ufsdirhash_findfree: Invalid dirhash %p\n", dh)); 696 DIRHASH_ASSERT_LOCKED(dh); 697 698 /* Find a directory block with the desired free space. */ 699 dirblock = -1; 700 for (i = howmany(slotneeded, DIRALIGN); i <= DH_NFSTATS; i++) 701 if ((dirblock = dh->dh_firstfree[i]) != -1) 702 break; 703 if (dirblock == -1) 704 return (-1); 705 706 KASSERT(dirblock < dh->dh_nblk && 707 dh->dh_blkfree[dirblock] >= howmany(slotneeded, DIRALIGN), 708 ("ufsdirhash_findfree: bad stats")); 709 pos = dirblock * DIRBLKSIZ; 710 error = UFS_BLKATOFF(ip->i_vnode, (off_t)pos, (char **)&dp, &bp); 711 if (error) 712 return (-1); 713 714 /* Find the first entry with free space. */ 715 for (i = 0; i < DIRBLKSIZ; ) { 716 if (dp->d_reclen == 0) { 717 brelse(bp); 718 return (-1); 719 } 720 if (dp->d_ino == 0 || dp->d_reclen > DIRSIZ(0, dp)) 721 break; 722 i += dp->d_reclen; 723 dp = (struct direct *)((char *)dp + dp->d_reclen); 724 } 725 if (i > DIRBLKSIZ) { 726 brelse(bp); 727 return (-1); 728 } 729 slotstart = pos + i; 730 731 /* Find the range of entries needed to get enough space */ 732 freebytes = 0; 733 while (i < DIRBLKSIZ && freebytes < slotneeded) { 734 freebytes += dp->d_reclen; 735 if (dp->d_ino != 0) 736 freebytes -= DIRSIZ(0, dp); 737 if (dp->d_reclen == 0) { 738 brelse(bp); 739 return (-1); 740 } 741 i += dp->d_reclen; 742 dp = (struct direct *)((char *)dp + dp->d_reclen); 743 } 744 if (i > DIRBLKSIZ) { 745 brelse(bp); 746 return (-1); 747 } 748 if (freebytes < slotneeded) 749 panic("ufsdirhash_findfree: free mismatch"); 750 brelse(bp); 751 *slotsize = pos + i - slotstart; 752 return (slotstart); 753} 754 755/* 756 * Return the start of the unused space at the end of a directory, or 757 * -1 if there are no trailing unused blocks. 758 */ 759doff_t 760ufsdirhash_enduseful(struct inode *ip) 761{ 762 763 struct dirhash *dh; 764 int i; 765 766 dh = ip->i_dirhash; 767 DIRHASH_ASSERT_LOCKED(dh); 768 KASSERT(dh != NULL && dh->dh_hash != NULL, 769 ("ufsdirhash_enduseful: Invalid dirhash %p\n", dh)); 770 771 if (dh->dh_blkfree[dh->dh_dirblks - 1] != DIRBLKSIZ / DIRALIGN) 772 return (-1); 773 774 for (i = dh->dh_dirblks - 1; i >= 0; i--) 775 if (dh->dh_blkfree[i] != DIRBLKSIZ / DIRALIGN) 776 break; 777 778 return ((doff_t)(i + 1) * DIRBLKSIZ); 779} 780 781/* 782 * Insert information into the hash about a new directory entry. dirp 783 * points to a struct direct containing the entry, and offset specifies 784 * the offset of this entry. 785 */ 786void 787ufsdirhash_add(struct inode *ip, struct direct *dirp, doff_t offset) 788{ 789 struct dirhash *dh; 790 int slot; 791 792 if ((dh = ufsdirhash_acquire(ip)) == NULL) 793 return; 794 795 KASSERT(offset < dh->dh_dirblks * DIRBLKSIZ, 796 ("ufsdirhash_add: bad offset")); 797 /* 798 * Normal hash usage is < 66%. If the usage gets too high then 799 * remove the hash entirely and let it be rebuilt later. 800 */ 801 if (dh->dh_hused >= (dh->dh_hlen * 3) / 4) { 802 ufsdirhash_free_locked(ip); 803 return; 804 } 805 806 /* Find a free hash slot (empty or deleted), and add the entry. */ 807 slot = ufsdirhash_hash(dh, dirp->d_name, dirp->d_namlen); 808 while (DH_ENTRY(dh, slot) >= 0) 809 slot = WRAPINCR(slot, dh->dh_hlen); 810 if (DH_ENTRY(dh, slot) == DIRHASH_EMPTY) 811 dh->dh_hused++; 812 DH_ENTRY(dh, slot) = offset; 813 814 /* Update the per-block summary info. */ 815 ufsdirhash_adjfree(dh, offset, -DIRSIZ(0, dirp)); 816 ufsdirhash_release(dh); 817} 818 819/* 820 * Remove the specified directory entry from the hash. The entry to remove 821 * is defined by the name in `dirp', which must exist at the specified 822 * `offset' within the directory. 823 */ 824void 825ufsdirhash_remove(struct inode *ip, struct direct *dirp, doff_t offset) 826{ 827 struct dirhash *dh; 828 int slot; 829 830 if ((dh = ufsdirhash_acquire(ip)) == NULL) 831 return; 832 833 KASSERT(offset < dh->dh_dirblks * DIRBLKSIZ, 834 ("ufsdirhash_remove: bad offset")); 835 /* Find the entry */ 836 slot = ufsdirhash_findslot(dh, dirp->d_name, dirp->d_namlen, offset); 837 838 /* Remove the hash entry. */ 839 ufsdirhash_delslot(dh, slot); 840 841 /* Update the per-block summary info. */ 842 ufsdirhash_adjfree(dh, offset, DIRSIZ(0, dirp)); 843 ufsdirhash_release(dh); 844} 845 846/* 847 * Change the offset associated with a directory entry in the hash. Used 848 * when compacting directory blocks. 849 */ 850void 851ufsdirhash_move(struct inode *ip, struct direct *dirp, doff_t oldoff, 852 doff_t newoff) 853{ 854 struct dirhash *dh; 855 int slot; 856 857 if ((dh = ufsdirhash_acquire(ip)) == NULL) 858 return; 859 860 KASSERT(oldoff < dh->dh_dirblks * DIRBLKSIZ && 861 newoff < dh->dh_dirblks * DIRBLKSIZ, 862 ("ufsdirhash_move: bad offset")); 863 /* Find the entry, and update the offset. */ 864 slot = ufsdirhash_findslot(dh, dirp->d_name, dirp->d_namlen, oldoff); 865 DH_ENTRY(dh, slot) = newoff; 866 ufsdirhash_release(dh); 867} 868 869/* 870 * Inform dirhash that the directory has grown by one block that 871 * begins at offset (i.e. the new length is offset + DIRBLKSIZ). 872 */ 873void 874ufsdirhash_newblk(struct inode *ip, doff_t offset) 875{ 876 struct dirhash *dh; 877 int block; 878 879 if ((dh = ufsdirhash_acquire(ip)) == NULL) 880 return; 881 882 KASSERT(offset == dh->dh_dirblks * DIRBLKSIZ, 883 ("ufsdirhash_newblk: bad offset")); 884 block = offset / DIRBLKSIZ; 885 if (block >= dh->dh_nblk) { 886 /* Out of space; must rebuild. */ 887 ufsdirhash_free_locked(ip); 888 return; 889 } 890 dh->dh_dirblks = block + 1; 891 892 /* Account for the new free block. */ 893 dh->dh_blkfree[block] = DIRBLKSIZ / DIRALIGN; 894 if (dh->dh_firstfree[DH_NFSTATS] == -1) 895 dh->dh_firstfree[DH_NFSTATS] = block; 896 ufsdirhash_release(dh); 897} 898 899/* 900 * Inform dirhash that the directory is being truncated. 901 */ 902void 903ufsdirhash_dirtrunc(struct inode *ip, doff_t offset) 904{ 905 struct dirhash *dh; 906 int block, i; 907 908 if ((dh = ufsdirhash_acquire(ip)) == NULL) 909 return; 910 911 KASSERT(offset <= dh->dh_dirblks * DIRBLKSIZ, 912 ("ufsdirhash_dirtrunc: bad offset")); 913 block = howmany(offset, DIRBLKSIZ); 914 /* 915 * If the directory shrinks to less than 1/8 of dh_nblk blocks 916 * (about 20% of its original size due to the 50% extra added in 917 * ufsdirhash_build) then free it, and let the caller rebuild 918 * if necessary. 919 */ 920 if (block < dh->dh_nblk / 8 && dh->dh_narrays > 1) { 921 ufsdirhash_free_locked(ip); 922 return; 923 } 924 925 /* 926 * Remove any `first free' information pertaining to the 927 * truncated blocks. All blocks we're removing should be 928 * completely unused. 929 */ 930 if (dh->dh_firstfree[DH_NFSTATS] >= block) 931 dh->dh_firstfree[DH_NFSTATS] = -1; 932 for (i = block; i < dh->dh_dirblks; i++) 933 if (dh->dh_blkfree[i] != DIRBLKSIZ / DIRALIGN) 934 panic("ufsdirhash_dirtrunc: blocks in use"); 935 for (i = 0; i < DH_NFSTATS; i++) 936 if (dh->dh_firstfree[i] >= block) 937 panic("ufsdirhash_dirtrunc: first free corrupt"); 938 dh->dh_dirblks = block; 939 ufsdirhash_release(dh); 940} 941 942/* 943 * Debugging function to check that the dirhash information about 944 * a directory block matches its actual contents. Panics if a mismatch 945 * is detected. 946 * 947 * On entry, `buf' should point to the start of an in-core 948 * DIRBLKSIZ-sized directory block, and `offset' should contain the 949 * offset from the start of the directory of that block. 950 */ 951void 952ufsdirhash_checkblock(struct inode *ip, char *buf, doff_t offset) 953{ 954 struct dirhash *dh; 955 struct direct *dp; 956 int block, ffslot, i, nfree; 957 958 if (!ufs_dirhashcheck) 959 return; 960 if ((dh = ufsdirhash_acquire(ip)) == NULL) 961 return; 962 963 block = offset / DIRBLKSIZ; 964 if ((offset & (DIRBLKSIZ - 1)) != 0 || block >= dh->dh_dirblks) 965 panic("ufsdirhash_checkblock: bad offset"); 966 967 nfree = 0; 968 for (i = 0; i < DIRBLKSIZ; i += dp->d_reclen) { 969 dp = (struct direct *)(buf + i); 970 if (dp->d_reclen == 0 || i + dp->d_reclen > DIRBLKSIZ) 971 panic("ufsdirhash_checkblock: bad dir"); 972 973 if (dp->d_ino == 0) { 974#if 0 975 /* 976 * XXX entries with d_ino == 0 should only occur 977 * at the start of a DIRBLKSIZ block. However the 978 * ufs code is tolerant of such entries at other 979 * offsets, and fsck does not fix them. 980 */ 981 if (i != 0) 982 panic("ufsdirhash_checkblock: bad dir inode"); 983#endif 984 nfree += dp->d_reclen; 985 continue; 986 } 987 988 /* Check that the entry exists (will panic if it doesn't). */ 989 ufsdirhash_findslot(dh, dp->d_name, dp->d_namlen, offset + i); 990 991 nfree += dp->d_reclen - DIRSIZ(0, dp); 992 } 993 if (i != DIRBLKSIZ) 994 panic("ufsdirhash_checkblock: bad dir end"); 995 996 if (dh->dh_blkfree[block] * DIRALIGN != nfree) 997 panic("ufsdirhash_checkblock: bad free count"); 998 999 ffslot = BLKFREE2IDX(nfree / DIRALIGN); 1000 for (i = 0; i <= DH_NFSTATS; i++) 1001 if (dh->dh_firstfree[i] == block && i != ffslot) 1002 panic("ufsdirhash_checkblock: bad first-free"); 1003 if (dh->dh_firstfree[ffslot] == -1) 1004 panic("ufsdirhash_checkblock: missing first-free entry"); 1005 ufsdirhash_release(dh); 1006} 1007 1008/* 1009 * Hash the specified filename into a dirhash slot. 1010 */ 1011static int 1012ufsdirhash_hash(struct dirhash *dh, char *name, int namelen) 1013{ 1014 u_int32_t hash; 1015 1016 /* 1017 * We hash the name and then some other bit of data that is 1018 * invariant over the dirhash's lifetime. Otherwise names 1019 * differing only in the last byte are placed close to one 1020 * another in the table, which is bad for linear probing. 1021 */ 1022 hash = fnv_32_buf(name, namelen, FNV1_32_INIT); 1023 hash = fnv_32_buf(&dh, sizeof(dh), hash); 1024 return (hash % dh->dh_hlen); 1025} 1026 1027/* 1028 * Adjust the number of free bytes in the block containing `offset' 1029 * by the value specified by `diff'. 1030 * 1031 * The caller must ensure we have exclusive access to `dh'; normally 1032 * that means that dh_lock should be held, but this is also called 1033 * from ufsdirhash_build() where exclusive access can be assumed. 1034 */ 1035static void 1036ufsdirhash_adjfree(struct dirhash *dh, doff_t offset, int diff) 1037{ 1038 int block, i, nfidx, ofidx; 1039 1040 /* Update the per-block summary info. */ 1041 block = offset / DIRBLKSIZ; 1042 KASSERT(block < dh->dh_nblk && block < dh->dh_dirblks, 1043 ("dirhash bad offset")); 1044 ofidx = BLKFREE2IDX(dh->dh_blkfree[block]); 1045 dh->dh_blkfree[block] = (int)dh->dh_blkfree[block] + (diff / DIRALIGN); 1046 nfidx = BLKFREE2IDX(dh->dh_blkfree[block]); 1047 1048 /* Update the `first free' list if necessary. */ 1049 if (ofidx != nfidx) { 1050 /* If removing, scan forward for the next block. */ 1051 if (dh->dh_firstfree[ofidx] == block) { 1052 for (i = block + 1; i < dh->dh_dirblks; i++) 1053 if (BLKFREE2IDX(dh->dh_blkfree[i]) == ofidx) 1054 break; 1055 dh->dh_firstfree[ofidx] = (i < dh->dh_dirblks) ? i : -1; 1056 } 1057 1058 /* Make this the new `first free' if necessary */ 1059 if (dh->dh_firstfree[nfidx] > block || 1060 dh->dh_firstfree[nfidx] == -1) 1061 dh->dh_firstfree[nfidx] = block; 1062 } 1063} 1064 1065/* 1066 * Find the specified name which should have the specified offset. 1067 * Returns a slot number, and panics on failure. 1068 * 1069 * `dh' must be locked on entry and remains so on return. 1070 */ 1071static int 1072ufsdirhash_findslot(struct dirhash *dh, char *name, int namelen, doff_t offset) 1073{ 1074 int slot; 1075 1076 DIRHASH_ASSERT_LOCKED(dh); 1077 1078 /* Find the entry. */ 1079 KASSERT(dh->dh_hused < dh->dh_hlen, ("dirhash find full")); 1080 slot = ufsdirhash_hash(dh, name, namelen); 1081 while (DH_ENTRY(dh, slot) != offset && 1082 DH_ENTRY(dh, slot) != DIRHASH_EMPTY) 1083 slot = WRAPINCR(slot, dh->dh_hlen); 1084 if (DH_ENTRY(dh, slot) != offset) 1085 panic("ufsdirhash_findslot: '%.*s' not found", namelen, name); 1086 1087 return (slot); 1088} 1089 1090/* 1091 * Remove the entry corresponding to the specified slot from the hash array. 1092 * 1093 * `dh' must be locked on entry and remains so on return. 1094 */ 1095static void 1096ufsdirhash_delslot(struct dirhash *dh, int slot) 1097{ 1098 int i; 1099 1100 DIRHASH_ASSERT_LOCKED(dh); 1101 1102 /* Mark the entry as deleted. */ 1103 DH_ENTRY(dh, slot) = DIRHASH_DEL; 1104 1105 /* If this is the end of a chain of DIRHASH_DEL slots, remove them. */ 1106 for (i = slot; DH_ENTRY(dh, i) == DIRHASH_DEL; ) 1107 i = WRAPINCR(i, dh->dh_hlen); 1108 if (DH_ENTRY(dh, i) == DIRHASH_EMPTY) { 1109 i = WRAPDECR(i, dh->dh_hlen); 1110 while (DH_ENTRY(dh, i) == DIRHASH_DEL) { 1111 DH_ENTRY(dh, i) = DIRHASH_EMPTY; 1112 dh->dh_hused--; 1113 i = WRAPDECR(i, dh->dh_hlen); 1114 } 1115 KASSERT(dh->dh_hused >= 0, ("ufsdirhash_delslot neg hlen")); 1116 } 1117} 1118 1119/* 1120 * Given a directory entry and its offset, find the offset of the 1121 * previous entry in the same DIRBLKSIZ-sized block. Returns an 1122 * offset, or -1 if there is no previous entry in the block or some 1123 * other problem occurred. 1124 */ 1125static doff_t 1126ufsdirhash_getprev(struct direct *dirp, doff_t offset) 1127{ 1128 struct direct *dp; 1129 char *blkbuf; 1130 doff_t blkoff, prevoff; 1131 int entrypos, i; 1132 1133 blkoff = offset & ~(DIRBLKSIZ - 1); /* offset of start of block */ 1134 entrypos = offset & (DIRBLKSIZ - 1); /* entry relative to block */ 1135 blkbuf = (char *)dirp - entrypos; 1136 prevoff = blkoff; 1137 1138 /* If `offset' is the start of a block, there is no previous entry. */ 1139 if (entrypos == 0) 1140 return (-1); 1141 1142 /* Scan from the start of the block until we get to the entry. */ 1143 for (i = 0; i < entrypos; i += dp->d_reclen) { 1144 dp = (struct direct *)(blkbuf + i); 1145 if (dp->d_reclen == 0 || i + dp->d_reclen > entrypos) 1146 return (-1); /* Corrupted directory. */ 1147 prevoff = blkoff + i; 1148 } 1149 return (prevoff); 1150} 1151 1152/* 1153 * Try to free up `wanted' bytes by stealing memory from existing 1154 * dirhashes. Returns zero with list locked if successful. 1155 */ 1156static int 1157ufsdirhash_recycle(int wanted) 1158{ 1159 struct dirhash *dh; 1160 doff_t **hash; 1161 u_int8_t *blkfree; 1162 int i, mem, narrays; 1163 1164 DIRHASHLIST_LOCK(); 1165 dh = TAILQ_FIRST(&ufsdirhash_list); 1166 while (wanted + ufs_dirhashmem > ufs_dirhashmaxmem) { 1167 /* Decrement the score; only recycle if it becomes zero. */ 1168 if (dh == NULL || --dh->dh_score > 0) { 1169 DIRHASHLIST_UNLOCK(); 1170 return (-1); 1171 } 1172 /* 1173 * If we can't lock it it's in use and we don't want to 1174 * recycle it anyway. 1175 */ 1176 if (!sx_try_xlock(&dh->dh_lock)) { 1177 dh = TAILQ_NEXT(dh, dh_list); 1178 continue; 1179 } 1180 KASSERT(dh->dh_hash != NULL, ("dirhash: NULL hash on list")); 1181 1182 /* Remove it from the list and detach its memory. */ 1183 TAILQ_REMOVE(&ufsdirhash_list, dh, dh_list); 1184 dh->dh_onlist = 0; 1185 hash = dh->dh_hash; 1186 dh->dh_hash = NULL; 1187 blkfree = dh->dh_blkfree; 1188 dh->dh_blkfree = NULL; 1189 narrays = dh->dh_narrays; 1190 mem = dh->dh_memreq; 1191 dh->dh_memreq = 0; 1192 1193 /* Unlock everything, free the detached memory. */ 1194 ufsdirhash_release(dh); 1195 DIRHASHLIST_UNLOCK(); 1196 for (i = 0; i < narrays; i++) 1197 DIRHASH_BLKFREE(hash[i]); 1198 free(hash, M_DIRHASH); 1199 free(blkfree, M_DIRHASH); 1200 1201 /* Account for the returned memory, and repeat if necessary. */ 1202 DIRHASHLIST_LOCK(); 1203 ufs_dirhashmem -= mem; 1204 dh = TAILQ_FIRST(&ufsdirhash_list); 1205 } 1206 /* Success; return with list locked. */ 1207 return (0); 1208} 1209 1210 1211void 1212ufsdirhash_init() 1213{ 1214 ufsdirhash_zone = uma_zcreate("DIRHASH", DH_NBLKOFF * sizeof(doff_t), 1215 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0); 1216 mtx_init(&ufsdirhash_mtx, "dirhash list", NULL, MTX_DEF); 1217 TAILQ_INIT(&ufsdirhash_list); 1218} 1219 1220void 1221ufsdirhash_uninit() 1222{ 1223 KASSERT(TAILQ_EMPTY(&ufsdirhash_list), ("ufsdirhash_uninit")); 1224 uma_zdestroy(ufsdirhash_zone); 1225 mtx_destroy(&ufsdirhash_mtx); 1226} 1227 1228#endif /* UFS_DIRHASH */ 1229