kern - Convert ufs dirhash from zalloc to objcache
[dragonfly.git] / sys / vfs / ufs / ufs_dirhash.c
CommitLineData
f719c866 1/*-
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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: src/sys/ufs/ufs/ufs_dirhash.c,v 1.3.2.6 2002/04/10 21:41:14 dwmalone Exp $
ac690a1d 26 * $DragonFly: src/sys/vfs/ufs/ufs_dirhash.c,v 1.6 2006/05/26 17:07:48 dillon Exp $
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27 */
28/*
29 * This implements a hash-based lookup scheme for UFS directories.
30 */
31
32#include "opt_ufs.h"
33
34#ifdef UFS_DIRHASH
35
36#include <sys/param.h>
37#include <sys/systm.h>
38#include <sys/kernel.h>
39#include <sys/malloc.h>
40#include <sys/fnv_hash.h>
41#include <sys/proc.h>
42#include <sys/buf.h>
43#include <sys/vnode.h>
44#include <sys/mount.h>
45#include <sys/sysctl.h>
f28cc8b8 46#include <sys/objcache.h>
984263bc 47
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48#include "quota.h"
49#include "inode.h"
50#include "dir.h"
51#include "dirhash.h"
52#include "ufsmount.h"
53#include "ufs_extern.h"
ac690a1d 54#include "ffs_extern.h"
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55
56#define WRAPINCR(val, limit) (((val) + 1 == (limit)) ? 0 : ((val) + 1))
57#define WRAPDECR(val, limit) (((val) == 0) ? ((limit) - 1) : ((val) - 1))
58#define OFSFMT(vp) ((vp)->v_mount->mnt_maxsymlinklen <= 0)
59#define BLKFREE2IDX(n) ((n) > DH_NFSTATS ? DH_NFSTATS : (n))
60
61static MALLOC_DEFINE(M_DIRHASH, "UFS dirhash", "UFS directory hash tables");
62
63SYSCTL_NODE(_vfs, OID_AUTO, ufs, CTLFLAG_RD, 0, "UFS filesystem");
64
65static int ufs_mindirhashsize = DIRBLKSIZ * 5;
66SYSCTL_INT(_vfs_ufs, OID_AUTO, dirhash_minsize, CTLFLAG_RW,
67 &ufs_mindirhashsize,
68 0, "minimum directory size in bytes for which to use hashed lookup");
69static int ufs_dirhashmaxmem = 2 * 1024 * 1024;
70SYSCTL_INT(_vfs_ufs, OID_AUTO, dirhash_maxmem, CTLFLAG_RW, &ufs_dirhashmaxmem,
71 0, "maximum allowed dirhash memory usage");
72static int ufs_dirhashmem;
73SYSCTL_INT(_vfs_ufs, OID_AUTO, dirhash_mem, CTLFLAG_RD, &ufs_dirhashmem,
74 0, "current dirhash memory usage");
75static int ufs_dirhashcheck = 0;
76SYSCTL_INT(_vfs_ufs, OID_AUTO, dirhash_docheck, CTLFLAG_RW, &ufs_dirhashcheck,
77 0, "enable extra sanity tests");
78
79
80static int ufsdirhash_hash(struct dirhash *dh, char *name, int namelen);
81static void ufsdirhash_adjfree(struct dirhash *dh, doff_t offset, int diff);
82static void ufsdirhash_delslot(struct dirhash *dh, int slot);
83static int ufsdirhash_findslot(struct dirhash *dh, char *name, int namelen,
84 doff_t offset);
85static doff_t ufsdirhash_getprev(struct direct *dp, doff_t offset);
86static void ufsdirhash_init(void);
87static int ufsdirhash_recycle(int wanted);
88
f28cc8b8 89static struct objcache *ufsdirhash_oc;
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90
91/* Dirhash list; recently-used entries are near the tail. */
92static TAILQ_HEAD(, dirhash) ufsdirhash_list;
93
94/*
95 * Attempt to build up a hash table for the directory contents in
96 * inode 'ip'. Returns 0 on success, or -1 of the operation failed.
97 */
98int
99ufsdirhash_build(struct inode *ip)
100{
101 struct dirhash *dh;
102 struct buf *bp = NULL;
103 struct direct *ep;
104 struct vnode *vp;
105 doff_t bmask, pos;
106 int dirblocks, i, j, memreqd, nblocks, narrays, nslots, slot;
107
108 /* Check if we can/should use dirhash. */
109 if (ip->i_dirhash == NULL) {
110 if (ip->i_size < ufs_mindirhashsize || OFSFMT(ip->i_vnode))
111 return (-1);
112 } else {
113 /* Hash exists, but sysctls could have changed. */
114 if (ip->i_size < ufs_mindirhashsize ||
115 ufs_dirhashmem > ufs_dirhashmaxmem) {
116 ufsdirhash_free(ip);
117 return (-1);
118 }
119 /* Check if hash exists and is intact (note: unlocked read). */
120 if (ip->i_dirhash->dh_hash != NULL)
121 return (0);
122 /* Free the old, recycled hash and build a new one. */
123 ufsdirhash_free(ip);
124 }
125
126 /* Don't hash removed directories. */
127 if (ip->i_effnlink == 0)
128 return (-1);
129
130 vp = ip->i_vnode;
131 /* Allocate 50% more entries than this dir size could ever need. */
132 KASSERT(ip->i_size >= DIRBLKSIZ, ("ufsdirhash_build size"));
133 nslots = ip->i_size / DIRECTSIZ(1);
134 nslots = (nslots * 3 + 1) / 2;
135 narrays = howmany(nslots, DH_NBLKOFF);
136 nslots = narrays * DH_NBLKOFF;
137 dirblocks = howmany(ip->i_size, DIRBLKSIZ);
138 nblocks = (dirblocks * 3 + 1) / 2;
139
140 memreqd = sizeof(*dh) + narrays * sizeof(*dh->dh_hash) +
141 narrays * DH_NBLKOFF * sizeof(**dh->dh_hash) +
142 nblocks * sizeof(*dh->dh_blkfree);
143 if (memreqd + ufs_dirhashmem > ufs_dirhashmaxmem) {
144 if (memreqd > ufs_dirhashmaxmem / 2)
145 return (-1);
146
147 /* Try to free some space. */
148 if (ufsdirhash_recycle(memreqd) != 0)
149 return (-1);
150 /* Enough was freed. */
151 }
152 ufs_dirhashmem += memreqd;
153
154 /*
155 * Use non-blocking mallocs so that we will revert to a linear
156 * lookup on failure rather than potentially blocking forever.
157 */
158 MALLOC(dh, struct dirhash *, sizeof *dh, M_DIRHASH, M_NOWAIT | M_ZERO);
159 if (dh == NULL)
160 return (-1);
161 MALLOC(dh->dh_hash, doff_t **, narrays * sizeof(dh->dh_hash[0]),
162 M_DIRHASH, M_NOWAIT | M_ZERO);
f719c866 163 MALLOC(dh->dh_blkfree, uint8_t *, nblocks * sizeof(dh->dh_blkfree[0]),
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164 M_DIRHASH, M_NOWAIT);
165 if (dh->dh_hash == NULL || dh->dh_blkfree == NULL)
166 goto fail;
167 for (i = 0; i < narrays; i++) {
f28cc8b8 168 if ((dh->dh_hash[i] = objcache_get(ufsdirhash_oc, M_WAITOK)) == NULL)
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169 goto fail;
170 for (j = 0; j < DH_NBLKOFF; j++)
171 dh->dh_hash[i][j] = DIRHASH_EMPTY;
172 }
173
174 /* Initialise the hash table and block statistics. */
175 dh->dh_narrays = narrays;
176 dh->dh_hlen = nslots;
177 dh->dh_nblk = nblocks;
178 dh->dh_dirblks = dirblocks;
179 for (i = 0; i < dirblocks; i++)
180 dh->dh_blkfree[i] = DIRBLKSIZ / DIRALIGN;
181 for (i = 0; i < DH_NFSTATS; i++)
182 dh->dh_firstfree[i] = -1;
183 dh->dh_firstfree[DH_NFSTATS] = 0;
184 dh->dh_seqopt = 0;
185 dh->dh_seqoff = 0;
186 dh->dh_score = DH_SCOREINIT;
187 ip->i_dirhash = dh;
188
189 bmask = VFSTOUFS(vp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
190 pos = 0;
191 while (pos < ip->i_size) {
192 /* If necessary, get the next directory block. */
193 if ((pos & bmask) == 0) {
194 if (bp != NULL)
195 brelse(bp);
ac690a1d 196 if (ffs_blkatoff(vp, (off_t)pos, NULL, &bp) != 0)
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197 goto fail;
198 }
199
200 /* Add this entry to the hash. */
201 ep = (struct direct *)((char *)bp->b_data + (pos & bmask));
202 if (ep->d_reclen == 0 || ep->d_reclen >
203 DIRBLKSIZ - (pos & (DIRBLKSIZ - 1))) {
204 /* Corrupted directory. */
205 brelse(bp);
206 goto fail;
207 }
208 if (ep->d_ino != 0) {
209 /* Add the entry (simplified ufsdirhash_add). */
210 slot = ufsdirhash_hash(dh, ep->d_name, ep->d_namlen);
211 while (DH_ENTRY(dh, slot) != DIRHASH_EMPTY)
212 slot = WRAPINCR(slot, dh->dh_hlen);
213 dh->dh_hused++;
214 DH_ENTRY(dh, slot) = pos;
215 ufsdirhash_adjfree(dh, pos, -DIRSIZ(0, ep));
216 }
217 pos += ep->d_reclen;
218 }
219
220 if (bp != NULL)
221 brelse(bp);
222 TAILQ_INSERT_TAIL(&ufsdirhash_list, dh, dh_list);
223 dh->dh_onlist = 1;
224 return (0);
225
226fail:
227 if (dh->dh_hash != NULL) {
228 for (i = 0; i < narrays; i++)
229 if (dh->dh_hash[i] != NULL)
f28cc8b8 230 objcache_put(ufsdirhash_oc, dh->dh_hash[i]);
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231 FREE(dh->dh_hash, M_DIRHASH);
232 }
233 if (dh->dh_blkfree != NULL)
234 FREE(dh->dh_blkfree, M_DIRHASH);
235 FREE(dh, M_DIRHASH);
236 ip->i_dirhash = NULL;
237 ufs_dirhashmem -= memreqd;
238 return (-1);
239}
240
241/*
242 * Free any hash table associated with inode 'ip'.
243 */
244void
245ufsdirhash_free(struct inode *ip)
246{
247 struct dirhash *dh;
248 int i, mem;
249
250 if ((dh = ip->i_dirhash) == NULL)
251 return;
252 if (dh->dh_onlist)
253 TAILQ_REMOVE(&ufsdirhash_list, dh, dh_list);
254
255 /* The dirhash pointed to by 'dh' is exclusively ours now. */
256
257 mem = sizeof(*dh);
258 if (dh->dh_hash != NULL) {
259 for (i = 0; i < dh->dh_narrays; i++)
f28cc8b8 260 objcache_put(ufsdirhash_oc, dh->dh_hash[i]);
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261 FREE(dh->dh_hash, M_DIRHASH);
262 FREE(dh->dh_blkfree, M_DIRHASH);
263 mem += dh->dh_narrays * sizeof(*dh->dh_hash) +
264 dh->dh_narrays * DH_NBLKOFF * sizeof(**dh->dh_hash) +
265 dh->dh_nblk * sizeof(*dh->dh_blkfree);
266 }
267 FREE(dh, M_DIRHASH);
268 ip->i_dirhash = NULL;
269
270 ufs_dirhashmem -= mem;
271}
272
273/*
274 * Find the offset of the specified name within the given inode.
275 * Returns 0 on success, ENOENT if the entry does not exist, or
276 * EJUSTRETURN if the caller should revert to a linear search.
277 *
278 * If successful, the directory offset is stored in *offp, and a
279 * pointer to a struct buf containing the entry is stored in *bpp. If
280 * prevoffp is non-NULL, the offset of the previous entry within
281 * the DIRBLKSIZ-sized block is stored in *prevoffp (if the entry
282 * is the first in a block, the start of the block is used).
283 */
284int
285ufsdirhash_lookup(struct inode *ip, char *name, int namelen, doff_t *offp,
0973c589 286 struct buf **bpp, doff_t *prevoffp)
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287{
288 struct dirhash *dh, *dh_next;
289 struct direct *dp;
290 struct vnode *vp;
291 struct buf *bp;
292 doff_t blkoff, bmask, offset, prevoff;
293 int i, slot;
294
295 if ((dh = ip->i_dirhash) == NULL)
296 return (EJUSTRETURN);
297 /*
298 * Move this dirhash towards the end of the list if it has a
299 * score higher than the next entry.
300 * Optimise the case where it's already the last by performing
301 * an unlocked read of the TAILQ_NEXT pointer.
302 */
303 if (TAILQ_NEXT(dh, dh_list) != NULL) {
304 /*
305 * If the new score will be greater than that of the next
306 * entry, then move this entry past it. With both mutexes
307 * held, dh_next won't go away, but its dh_score could
308 * change; that's not important since it is just a hint.
309 */
310 if (dh->dh_hash != NULL &&
311 (dh_next = TAILQ_NEXT(dh, dh_list)) != NULL &&
312 dh->dh_score >= dh_next->dh_score) {
313 KASSERT(dh->dh_onlist, ("dirhash: not on list"));
314 TAILQ_REMOVE(&ufsdirhash_list, dh, dh_list);
315 TAILQ_INSERT_AFTER(&ufsdirhash_list, dh_next, dh,
316 dh_list);
317 }
318 }
319 if (dh->dh_hash == NULL) {
320 ufsdirhash_free(ip);
321 return (EJUSTRETURN);
322 }
323
324 /* Update the score. */
325 if (dh->dh_score < DH_SCOREMAX)
326 dh->dh_score++;
327
328 vp = ip->i_vnode;
329 bmask = VFSTOUFS(vp->v_mount)->um_mountp->mnt_stat.f_iosize - 1;
330 blkoff = -1;
331 bp = NULL;
332restart:
333 slot = ufsdirhash_hash(dh, name, namelen);
334
335 if (dh->dh_seqopt) {
336 /*
337 * Sequential access optimisation. dh_seqoff contains the
338 * offset of the directory entry immediately following
339 * the last entry that was looked up. Check if this offset
340 * appears in the hash chain for the name we are looking for.
341 */
342 for (i = slot; (offset = DH_ENTRY(dh, i)) != DIRHASH_EMPTY;
343 i = WRAPINCR(i, dh->dh_hlen))
344 if (offset == dh->dh_seqoff)
345 break;
346 if (offset == dh->dh_seqoff) {
347 /*
348 * We found an entry with the expected offset. This
349 * is probably the entry we want, but if not, the
350 * code below will turn off seqoff and retry.
351 */
352 slot = i;
353 } else
354 dh->dh_seqopt = 0;
355 }
356
357 for (; (offset = DH_ENTRY(dh, slot)) != DIRHASH_EMPTY;
358 slot = WRAPINCR(slot, dh->dh_hlen)) {
359 if (offset == DIRHASH_DEL)
360 continue;
361
362 if (offset < 0 || offset >= ip->i_size)
363 panic("ufsdirhash_lookup: bad offset in hash array");
364 if ((offset & ~bmask) != blkoff) {
365 if (bp != NULL)
366 brelse(bp);
367 blkoff = offset & ~bmask;
ac690a1d 368 if (ffs_blkatoff(vp, (off_t)blkoff, NULL, &bp) != 0)
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369 return (EJUSTRETURN);
370 }
371 dp = (struct direct *)(bp->b_data + (offset & bmask));
372 if (dp->d_reclen == 0 || dp->d_reclen >
373 DIRBLKSIZ - (offset & (DIRBLKSIZ - 1))) {
374 /* Corrupted directory. */
375 brelse(bp);
376 return (EJUSTRETURN);
377 }
378 if (dp->d_namlen == namelen &&
379 bcmp(dp->d_name, name, namelen) == 0) {
380 /* Found. Get the prev offset if needed. */
381 if (prevoffp != NULL) {
382 if (offset & (DIRBLKSIZ - 1)) {
383 prevoff = ufsdirhash_getprev(dp,
384 offset);
385 if (prevoff == -1) {
386 brelse(bp);
387 return (EJUSTRETURN);
388 }
389 } else
390 prevoff = offset;
391 *prevoffp = prevoff;
392 }
393
394 /* Check for sequential access, and update offset. */
395 if (dh->dh_seqopt == 0 && dh->dh_seqoff == offset)
396 dh->dh_seqopt = 1;
397 dh->dh_seqoff = offset + DIRSIZ(0, dp);
398
399 *bpp = bp;
400 *offp = offset;
401 return (0);
402 }
403
404 if (dh->dh_hash == NULL) {
405 if (bp != NULL)
406 brelse(bp);
407 ufsdirhash_free(ip);
408 return (EJUSTRETURN);
409 }
410 /*
411 * When the name doesn't match in the seqopt case, go back
412 * and search normally.
413 */
414 if (dh->dh_seqopt) {
415 dh->dh_seqopt = 0;
416 goto restart;
417 }
418 }
419 if (bp != NULL)
420 brelse(bp);
421 return (ENOENT);
422}
423
424/*
425 * Find a directory block with room for 'slotneeded' bytes. Returns
426 * the offset of the directory entry that begins the free space.
427 * This will either be the offset of an existing entry that has free
428 * space at the end, or the offset of an entry with d_ino == 0 at
429 * the start of a DIRBLKSIZ block.
430 *
431 * To use the space, the caller may need to compact existing entries in
432 * the directory. The total number of bytes in all of the entries involved
433 * in the compaction is stored in *slotsize. In other words, all of
434 * the entries that must be compacted are exactly contained in the
435 * region beginning at the returned offset and spanning *slotsize bytes.
436 *
437 * Returns -1 if no space was found, indicating that the directory
438 * must be extended.
439 */
440doff_t
441ufsdirhash_findfree(struct inode *ip, int slotneeded, int *slotsize)
442{
443 struct direct *dp;
444 struct dirhash *dh;
445 struct buf *bp;
446 doff_t pos, slotstart;
447 int dirblock, error, freebytes, i;
448
449 if ((dh = ip->i_dirhash) == NULL)
450 return (-1);
451 if (dh->dh_hash == NULL) {
452 ufsdirhash_free(ip);
453 return (-1);
454 }
455
456 /* Find a directory block with the desired free space. */
457 dirblock = -1;
458 for (i = howmany(slotneeded, DIRALIGN); i <= DH_NFSTATS; i++)
459 if ((dirblock = dh->dh_firstfree[i]) != -1)
460 break;
461 if (dirblock == -1) {
462 return (-1);
463 }
464
465 KASSERT(dirblock < dh->dh_nblk &&
466 dh->dh_blkfree[dirblock] >= howmany(slotneeded, DIRALIGN),
467 ("ufsdirhash_findfree: bad stats"));
468 pos = dirblock * DIRBLKSIZ;
ac690a1d 469 error = ffs_blkatoff(ip->i_vnode, (off_t)pos, (char **)&dp, &bp);
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470 if (error)
471 return (-1);
472
473 /* Find the first entry with free space. */
474 for (i = 0; i < DIRBLKSIZ; ) {
475 if (dp->d_reclen == 0) {
476 brelse(bp);
477 return (-1);
478 }
479 if (dp->d_ino == 0 || dp->d_reclen > DIRSIZ(0, dp))
480 break;
481 i += dp->d_reclen;
482 dp = (struct direct *)((char *)dp + dp->d_reclen);
483 }
484 if (i > DIRBLKSIZ) {
485 brelse(bp);
486 return (-1);
487 }
488 slotstart = pos + i;
489
490 /* Find the range of entries needed to get enough space */
491 freebytes = 0;
492 while (i < DIRBLKSIZ && freebytes < slotneeded) {
493 freebytes += dp->d_reclen;
494 if (dp->d_ino != 0)
495 freebytes -= DIRSIZ(0, dp);
496 if (dp->d_reclen == 0) {
497 brelse(bp);
498 return (-1);
499 }
500 i += dp->d_reclen;
501 dp = (struct direct *)((char *)dp + dp->d_reclen);
502 }
503 if (i > DIRBLKSIZ) {
504 brelse(bp);
505 return (-1);
506 }
507 if (freebytes < slotneeded)
508 panic("ufsdirhash_findfree: free mismatch");
509 brelse(bp);
510 *slotsize = pos + i - slotstart;
511 return (slotstart);
512}
513
514/*
515 * Return the start of the unused space at the end of a directory, or
516 * -1 if there are no trailing unused blocks.
517 */
518doff_t
519ufsdirhash_enduseful(struct inode *ip)
520{
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521 struct dirhash *dh;
522 int i;
523
524 if ((dh = ip->i_dirhash) == NULL)
525 return (-1);
526 if (dh->dh_hash == NULL) {
527 ufsdirhash_free(ip);
528 return (-1);
529 }
530
531 if (dh->dh_blkfree[dh->dh_dirblks - 1] != DIRBLKSIZ / DIRALIGN) {
532 return (-1);
533 }
534
535 for (i = dh->dh_dirblks - 1; i >= 0; i--)
536 if (dh->dh_blkfree[i] != DIRBLKSIZ / DIRALIGN)
537 break;
538 return ((doff_t)(i + 1) * DIRBLKSIZ);
539}
540
541/*
542 * Insert information into the hash about a new directory entry. dirp
543 * points to a struct direct containing the entry, and offset specifies
544 * the offset of this entry.
545 */
546void
547ufsdirhash_add(struct inode *ip, struct direct *dirp, doff_t offset)
548{
549 struct dirhash *dh;
550 int slot;
551
552 if ((dh = ip->i_dirhash) == NULL)
553 return;
554 if (dh->dh_hash == NULL) {
555 ufsdirhash_free(ip);
556 return;
557 }
558
559 KASSERT(offset < dh->dh_dirblks * DIRBLKSIZ,
560 ("ufsdirhash_add: bad offset"));
561 /*
562 * Normal hash usage is < 66%. If the usage gets too high then
563 * remove the hash entirely and let it be rebuilt later.
564 */
565 if (dh->dh_hused >= (dh->dh_hlen * 3) / 4) {
566 ufsdirhash_free(ip);
567 return;
568 }
569
570 /* Find a free hash slot (empty or deleted), and add the entry. */
571 slot = ufsdirhash_hash(dh, dirp->d_name, dirp->d_namlen);
572 while (DH_ENTRY(dh, slot) >= 0)
573 slot = WRAPINCR(slot, dh->dh_hlen);
574 if (DH_ENTRY(dh, slot) == DIRHASH_EMPTY)
575 dh->dh_hused++;
576 DH_ENTRY(dh, slot) = offset;
577
578 /* Update the per-block summary info. */
579 ufsdirhash_adjfree(dh, offset, -DIRSIZ(0, dirp));
580}
581
582/*
583 * Remove the specified directory entry from the hash. The entry to remove
584 * is defined by the name in `dirp', which must exist at the specified
585 * `offset' within the directory.
586 */
587void
588ufsdirhash_remove(struct inode *ip, struct direct *dirp, doff_t offset)
589{
590 struct dirhash *dh;
591 int slot;
592
593 if ((dh = ip->i_dirhash) == NULL)
594 return;
595 if (dh->dh_hash == NULL) {
596 ufsdirhash_free(ip);
597 return;
598 }
599
600 KASSERT(offset < dh->dh_dirblks * DIRBLKSIZ,
601 ("ufsdirhash_remove: bad offset"));
602 /* Find the entry */
603 slot = ufsdirhash_findslot(dh, dirp->d_name, dirp->d_namlen, offset);
604
605 /* Remove the hash entry. */
606 ufsdirhash_delslot(dh, slot);
607
608 /* Update the per-block summary info. */
609 ufsdirhash_adjfree(dh, offset, DIRSIZ(0, dirp));
610}
611
612/*
613 * Change the offset associated with a directory entry in the hash. Used
614 * when compacting directory blocks.
615 */
616void
617ufsdirhash_move(struct inode *ip, struct direct *dirp, doff_t oldoff,
0973c589 618 doff_t newoff)
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619{
620 struct dirhash *dh;
621 int slot;
622
623 if ((dh = ip->i_dirhash) == NULL)
624 return;
625 if (dh->dh_hash == NULL) {
626 ufsdirhash_free(ip);
627 return;
628 }
629
630 KASSERT(oldoff < dh->dh_dirblks * DIRBLKSIZ &&
631 newoff < dh->dh_dirblks * DIRBLKSIZ,
632 ("ufsdirhash_move: bad offset"));
633 /* Find the entry, and update the offset. */
634 slot = ufsdirhash_findslot(dh, dirp->d_name, dirp->d_namlen, oldoff);
635 DH_ENTRY(dh, slot) = newoff;
636}
637
638/*
639 * Inform dirhash that the directory has grown by one block that
640 * begins at offset (i.e. the new length is offset + DIRBLKSIZ).
641 */
642void
643ufsdirhash_newblk(struct inode *ip, doff_t offset)
644{
645 struct dirhash *dh;
646 int block;
647
648 if ((dh = ip->i_dirhash) == NULL)
649 return;
650 if (dh->dh_hash == NULL) {
651 ufsdirhash_free(ip);
652 return;
653 }
654
655 KASSERT(offset == dh->dh_dirblks * DIRBLKSIZ,
656 ("ufsdirhash_newblk: bad offset"));
657 block = offset / DIRBLKSIZ;
658 if (block >= dh->dh_nblk) {
659 /* Out of space; must rebuild. */
660 ufsdirhash_free(ip);
661 return;
662 }
663 dh->dh_dirblks = block + 1;
664
665 /* Account for the new free block. */
666 dh->dh_blkfree[block] = DIRBLKSIZ / DIRALIGN;
667 if (dh->dh_firstfree[DH_NFSTATS] == -1)
668 dh->dh_firstfree[DH_NFSTATS] = block;
669}
670
671/*
672 * Inform dirhash that the directory is being truncated.
673 */
674void
675ufsdirhash_dirtrunc(struct inode *ip, doff_t offset)
676{
677 struct dirhash *dh;
678 int block, i;
679
680 if ((dh = ip->i_dirhash) == NULL)
681 return;
682 if (dh->dh_hash == NULL) {
683 ufsdirhash_free(ip);
684 return;
685 }
686
687 KASSERT(offset <= dh->dh_dirblks * DIRBLKSIZ,
688 ("ufsdirhash_dirtrunc: bad offset"));
689 block = howmany(offset, DIRBLKSIZ);
690 /*
691 * If the directory shrinks to less than 1/8 of dh_nblk blocks
692 * (about 20% of its original size due to the 50% extra added in
693 * ufsdirhash_build) then free it, and let the caller rebuild
694 * if necessary.
695 */
696 if (block < dh->dh_nblk / 8 && dh->dh_narrays > 1) {
697 ufsdirhash_free(ip);
698 return;
699 }
700
701 /*
702 * Remove any `first free' information pertaining to the
703 * truncated blocks. All blocks we're removing should be
704 * completely unused.
705 */
706 if (dh->dh_firstfree[DH_NFSTATS] >= block)
707 dh->dh_firstfree[DH_NFSTATS] = -1;
708 for (i = block; i < dh->dh_dirblks; i++)
709 if (dh->dh_blkfree[i] != DIRBLKSIZ / DIRALIGN)
710 panic("ufsdirhash_dirtrunc: blocks in use");
711 for (i = 0; i < DH_NFSTATS; i++)
712 if (dh->dh_firstfree[i] >= block)
713 panic("ufsdirhash_dirtrunc: first free corrupt");
714 dh->dh_dirblks = block;
715}
716
717/*
718 * Debugging function to check that the dirhash information about
719 * a directory block matches its actual contents. Panics if a mismatch
720 * is detected.
721 *
722 * On entry, `buf' should point to the start of an in-core
723 * DIRBLKSIZ-sized directory block, and `offset' should contain the
724 * offset from the start of the directory of that block.
725 */
726void
727ufsdirhash_checkblock(struct inode *ip, char *buf, doff_t offset)
728{
729 struct dirhash *dh;
730 struct direct *dp;
731 int block, ffslot, i, nfree;
732
733 if (!ufs_dirhashcheck)
734 return;
735 if ((dh = ip->i_dirhash) == NULL)
736 return;
737 if (dh->dh_hash == NULL) {
738 ufsdirhash_free(ip);
739 return;
740 }
741
742 block = offset / DIRBLKSIZ;
743 if ((offset & (DIRBLKSIZ - 1)) != 0 || block >= dh->dh_dirblks)
744 panic("ufsdirhash_checkblock: bad offset");
745
746 nfree = 0;
747 for (i = 0; i < DIRBLKSIZ; i += dp->d_reclen) {
748 dp = (struct direct *)(buf + i);
749 if (dp->d_reclen == 0 || i + dp->d_reclen > DIRBLKSIZ)
750 panic("ufsdirhash_checkblock: bad dir");
751
752 if (dp->d_ino == 0) {
753#if 0
754 /*
755 * XXX entries with d_ino == 0 should only occur
756 * at the start of a DIRBLKSIZ block. However the
757 * ufs code is tolerant of such entries at other
758 * offsets, and fsck does not fix them.
759 */
760 if (i != 0)
761 panic("ufsdirhash_checkblock: bad dir inode");
762#endif
763 nfree += dp->d_reclen;
764 continue;
765 }
766
767 /* Check that the entry exists (will panic if it doesn't). */
768 ufsdirhash_findslot(dh, dp->d_name, dp->d_namlen, offset + i);
769
770 nfree += dp->d_reclen - DIRSIZ(0, dp);
771 }
772 if (i != DIRBLKSIZ)
773 panic("ufsdirhash_checkblock: bad dir end");
774
775 if (dh->dh_blkfree[block] * DIRALIGN != nfree)
776 panic("ufsdirhash_checkblock: bad free count");
777
778 ffslot = BLKFREE2IDX(nfree / DIRALIGN);
779 for (i = 0; i <= DH_NFSTATS; i++)
780 if (dh->dh_firstfree[i] == block && i != ffslot)
781 panic("ufsdirhash_checkblock: bad first-free");
782 if (dh->dh_firstfree[ffslot] == -1)
783 panic("ufsdirhash_checkblock: missing first-free entry");
784}
785
786/*
787 * Hash the specified filename into a dirhash slot.
788 */
789static int
790ufsdirhash_hash(struct dirhash *dh, char *name, int namelen)
791{
f719c866 792 uint32_t hash;
984263bc
MD
793
794 /*
795 * We hash the name and then some ofther bit of data which is
796 * invarient over the dirhash's lifetime. Otherwise names
797 * differing only in the last byte are placed close to one
798 * another in the table, which is bad for linear probing.
799 */
800 hash = fnv_32_buf(name, namelen, FNV1_32_INIT);
801 hash = fnv_32_buf(dh, sizeof(dh), hash);
802 return (hash % dh->dh_hlen);
803}
804
805/*
806 * Adjust the number of free bytes in the block containing `offset'
807 * by the value specified by `diff'.
808 *
809 * The caller must ensure we have exclusive access to `dh'.
810 */
811static void
812ufsdirhash_adjfree(struct dirhash *dh, doff_t offset, int diff)
813{
814 int block, i, nfidx, ofidx;
815
816 /* Update the per-block summary info. */
817 block = offset / DIRBLKSIZ;
818 KASSERT(block < dh->dh_nblk && block < dh->dh_dirblks,
819 ("dirhash bad offset"));
820 ofidx = BLKFREE2IDX(dh->dh_blkfree[block]);
821 dh->dh_blkfree[block] = (int)dh->dh_blkfree[block] + (diff / DIRALIGN);
822 nfidx = BLKFREE2IDX(dh->dh_blkfree[block]);
823
824 /* Update the `first free' list if necessary. */
825 if (ofidx != nfidx) {
826 /* If removing, scan forward for the next block. */
827 if (dh->dh_firstfree[ofidx] == block) {
828 for (i = block + 1; i < dh->dh_dirblks; i++)
829 if (BLKFREE2IDX(dh->dh_blkfree[i]) == ofidx)
830 break;
831 dh->dh_firstfree[ofidx] = (i < dh->dh_dirblks) ? i : -1;
832 }
833
834 /* Make this the new `first free' if necessary */
835 if (dh->dh_firstfree[nfidx] > block ||
836 dh->dh_firstfree[nfidx] == -1)
837 dh->dh_firstfree[nfidx] = block;
838 }
839}
840
841/*
842 * Find the specified name which should have the specified offset.
843 * Returns a slot number, and panics on failure.
844 *
845 * `dh' must be locked on entry and remains so on return.
846 */
847static int
848ufsdirhash_findslot(struct dirhash *dh, char *name, int namelen, doff_t offset)
849{
850 int slot;
851
852 /* Find the entry. */
853 KASSERT(dh->dh_hused < dh->dh_hlen, ("dirhash find full"));
854 slot = ufsdirhash_hash(dh, name, namelen);
855 while (DH_ENTRY(dh, slot) != offset &&
856 DH_ENTRY(dh, slot) != DIRHASH_EMPTY)
857 slot = WRAPINCR(slot, dh->dh_hlen);
858 if (DH_ENTRY(dh, slot) != offset)
859 panic("ufsdirhash_findslot: '%.*s' not found", namelen, name);
860
861 return (slot);
862}
863
864/*
865 * Remove the entry corresponding to the specified slot from the hash array.
866 *
867 * `dh' must be locked on entry and remains so on return.
868 */
869static void
870ufsdirhash_delslot(struct dirhash *dh, int slot)
871{
872 int i;
873
874 /* Mark the entry as deleted. */
875 DH_ENTRY(dh, slot) = DIRHASH_DEL;
876
877 /* If this is the end of a chain of DIRHASH_DEL slots, remove them. */
878 for (i = slot; DH_ENTRY(dh, i) == DIRHASH_DEL; )
879 i = WRAPINCR(i, dh->dh_hlen);
880 if (DH_ENTRY(dh, i) == DIRHASH_EMPTY) {
881 i = WRAPDECR(i, dh->dh_hlen);
882 while (DH_ENTRY(dh, i) == DIRHASH_DEL) {
883 DH_ENTRY(dh, i) = DIRHASH_EMPTY;
884 dh->dh_hused--;
885 i = WRAPDECR(i, dh->dh_hlen);
886 }
887 KASSERT(dh->dh_hused >= 0, ("ufsdirhash_delslot neg hlen"));
888 }
889}
890
891/*
892 * Given a directory entry and its offset, find the offset of the
893 * previous entry in the same DIRBLKSIZ-sized block. Returns an
894 * offset, or -1 if there is no previous entry in the block or some
895 * other problem occurred.
896 */
897static doff_t
898ufsdirhash_getprev(struct direct *dirp, doff_t offset)
899{
900 struct direct *dp;
901 char *blkbuf;
902 doff_t blkoff, prevoff;
903 int entrypos, i;
904
905 blkoff = offset & ~(DIRBLKSIZ - 1); /* offset of start of block */
906 entrypos = offset & (DIRBLKSIZ - 1); /* entry relative to block */
907 blkbuf = (char *)dirp - entrypos;
908 prevoff = blkoff;
909
910 /* If `offset' is the start of a block, there is no previous entry. */
911 if (entrypos == 0)
912 return (-1);
913
914 /* Scan from the start of the block until we get to the entry. */
915 for (i = 0; i < entrypos; i += dp->d_reclen) {
916 dp = (struct direct *)(blkbuf + i);
917 if (dp->d_reclen == 0 || i + dp->d_reclen > entrypos)
918 return (-1); /* Corrupted directory. */
919 prevoff = blkoff + i;
920 }
921 return (prevoff);
922}
923
924/*
925 * Try to free up `wanted' bytes by stealing memory from existing
926 * dirhashes. Returns zero if successful.
927 */
928static int
929ufsdirhash_recycle(int wanted)
930{
931 struct dirhash *dh;
932 doff_t **hash;
f719c866 933 uint8_t *blkfree;
984263bc
MD
934 int i, mem, narrays;
935
936 while (wanted + ufs_dirhashmem > ufs_dirhashmaxmem) {
937 /* Find a dirhash, and lock it. */
938 if ((dh = TAILQ_FIRST(&ufsdirhash_list)) == NULL) {
939 return (-1);
940 }
941 KASSERT(dh->dh_hash != NULL, ("dirhash: NULL hash on list"));
942
943 /* Decrement the score; only recycle if it becomes zero. */
944 if (--dh->dh_score > 0) {
945 return (-1);
946 }
947
948 /* Remove it from the list and detach its memory. */
949 TAILQ_REMOVE(&ufsdirhash_list, dh, dh_list);
950 dh->dh_onlist = 0;
951 hash = dh->dh_hash;
952 dh->dh_hash = NULL;
953 blkfree = dh->dh_blkfree;
954 dh->dh_blkfree = NULL;
955 narrays = dh->dh_narrays;
956 mem = narrays * sizeof(*dh->dh_hash) +
957 narrays * DH_NBLKOFF * sizeof(**dh->dh_hash) +
958 dh->dh_nblk * sizeof(*dh->dh_blkfree);
959
960 /* Free the detached memory. */
961 for (i = 0; i < narrays; i++)
f28cc8b8 962 objcache_put(ufsdirhash_oc, hash[i]);
984263bc
MD
963 FREE(hash, M_DIRHASH);
964 FREE(blkfree, M_DIRHASH);
965
966 /* Account for the returned memory, and repeat if necessary. */
967 ufs_dirhashmem -= mem;
968 }
969 /* Success. */
970 return (0);
971}
972
973
974static void
0973c589 975ufsdirhash_init(void)
984263bc 976{
f28cc8b8
SG
977 ufsdirhash_oc = objcache_create_simple(M_DIRHASH,
978 DH_NBLKOFF * sizeof(daddr_t));
984263bc
MD
979 TAILQ_INIT(&ufsdirhash_list);
980}
981SYSINIT(ufsdirhash, SI_SUB_PSEUDO, SI_ORDER_ANY, ufsdirhash_init, NULL)
982
983
984#endif /* UFS_DIRHASH */