| 1 | /* $NetBSD: vfs_dirhash.c,v 1.12 2014/09/05 05:57:21 matt Exp $ */ |
| 2 | |
| 3 | /* |
| 4 | * Copyright (c) 2008 Reinoud Zandijk |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * Redistribution and use in source and binary forms, with or without |
| 8 | * modification, are permitted provided that the following conditions |
| 9 | * are met: |
| 10 | * 1. Redistributions of source code must retain the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer. |
| 12 | * 2. Redistributions in binary form must reproduce the above copyright |
| 13 | * notice, this list of conditions and the following disclaimer in the |
| 14 | * documentation and/or other materials provided with the distribution. |
| 15 | * |
| 16 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 17 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 18 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 19 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 20 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 21 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 22 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 23 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 24 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 25 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 26 | * |
| 27 | */ |
| 28 | |
| 29 | |
| 30 | #include <sys/cdefs.h> |
| 31 | __KERNEL_RCSID(0, "$NetBSD: vfs_dirhash.c,v 1.12 2014/09/05 05:57:21 matt Exp $" ); |
| 32 | |
| 33 | /* CLEAN UP! */ |
| 34 | #include <sys/param.h> |
| 35 | #include <sys/kernel.h> |
| 36 | #include <sys/buf.h> |
| 37 | #include <sys/dirent.h> |
| 38 | #include <sys/hash.h> |
| 39 | #include <sys/mutex.h> |
| 40 | #include <sys/pool.h> |
| 41 | #include <sys/queue.h> |
| 42 | #include <sys/vnode.h> |
| 43 | #include <sys/sysctl.h> |
| 44 | |
| 45 | #include <sys/dirhash.h> |
| 46 | |
| 47 | #if 1 |
| 48 | # define DPRINTF(a) ; |
| 49 | #else |
| 50 | # define DPRINTF(a) printf a; |
| 51 | #endif |
| 52 | |
| 53 | /* |
| 54 | * The locking protocol of the dirhash structures is fairly simple: |
| 55 | * |
| 56 | * The global dirhash_queue is protected by the dirhashmutex. This lock is |
| 57 | * internal only and is FS/mountpoint/vnode independent. On exit of the |
| 58 | * exported functions this mutex is not helt. |
| 59 | * |
| 60 | * The dirhash structure is considered part of the vnode/inode/udf_node |
| 61 | * structure and will thus use the lock that protects that vnode/inode. |
| 62 | * |
| 63 | * The dirhash entries are considered part of the dirhash structure and thus |
| 64 | * are on the same lock. |
| 65 | */ |
| 66 | |
| 67 | static struct sysctllog *sysctl_log; |
| 68 | static struct pool dirhash_pool; |
| 69 | static struct pool dirhash_entry_pool; |
| 70 | |
| 71 | static kmutex_t dirhashmutex; |
| 72 | static uint32_t maxdirhashsize = DIRHASH_SIZE; |
| 73 | static uint32_t dirhashsize = 0; |
| 74 | static TAILQ_HEAD(_dirhash, dirhash) dirhash_queue; |
| 75 | |
| 76 | |
| 77 | void |
| 78 | dirhash_init(void) |
| 79 | { |
| 80 | const struct sysctlnode *rnode, *cnode; |
| 81 | size_t sz; |
| 82 | uint32_t max_entries; |
| 83 | |
| 84 | /* initialise dirhash queue */ |
| 85 | TAILQ_INIT(&dirhash_queue); |
| 86 | |
| 87 | /* init dirhash pools */ |
| 88 | sz = sizeof(struct dirhash); |
| 89 | pool_init(&dirhash_pool, sz, 0, 0, 0, |
| 90 | "dirhpl" , NULL, IPL_NONE); |
| 91 | |
| 92 | sz = sizeof(struct dirhash_entry); |
| 93 | pool_init(&dirhash_entry_pool, sz, 0, 0, 0, |
| 94 | "dirhepl" , NULL, IPL_NONE); |
| 95 | |
| 96 | mutex_init(&dirhashmutex, MUTEX_DEFAULT, IPL_NONE); |
| 97 | max_entries = maxdirhashsize / sz; |
| 98 | pool_sethiwat(&dirhash_entry_pool, max_entries); |
| 99 | dirhashsize = 0; |
| 100 | |
| 101 | /* create sysctl knobs and dials */ |
| 102 | sysctl_log = NULL; |
| 103 | sysctl_createv(&sysctl_log, 0, NULL, &rnode, |
| 104 | CTLFLAG_PERMANENT, |
| 105 | CTLTYPE_NODE, "dirhash" , NULL, |
| 106 | NULL, 0, NULL, 0, |
| 107 | CTL_VFS, VFS_GENERIC, CTL_CREATE, CTL_EOL); |
| 108 | sysctl_createv(&sysctl_log, 0, &rnode, &cnode, |
| 109 | CTLFLAG_PERMANENT, |
| 110 | CTLTYPE_INT, "memused" , |
| 111 | SYSCTL_DESCR("current dirhash memory usage" ), |
| 112 | NULL, 0, &dirhashsize, 0, |
| 113 | CTL_CREATE, CTL_EOL); |
| 114 | sysctl_createv(&sysctl_log, 0, &rnode, &cnode, |
| 115 | CTLFLAG_PERMANENT | CTLFLAG_READWRITE, |
| 116 | CTLTYPE_INT, "maxmem" , |
| 117 | SYSCTL_DESCR("maximum dirhash memory usage" ), |
| 118 | NULL, 0, &maxdirhashsize, 0, |
| 119 | CTL_CREATE, CTL_EOL); |
| 120 | } |
| 121 | |
| 122 | |
| 123 | #if 0 |
| 124 | void |
| 125 | dirhash_finish(void) |
| 126 | { |
| 127 | pool_destroy(&dirhash_pool); |
| 128 | pool_destroy(&dirhash_entry_pool); |
| 129 | |
| 130 | mutex_destroy(&dirhashmutex); |
| 131 | |
| 132 | /* sysctl_teardown(&sysctl_log); */ |
| 133 | } |
| 134 | #endif |
| 135 | |
| 136 | |
| 137 | /* |
| 138 | * generic dirhash implementation |
| 139 | */ |
| 140 | |
| 141 | void |
| 142 | dirhash_purge_entries(struct dirhash *dirh) |
| 143 | { |
| 144 | struct dirhash_entry *dirh_e; |
| 145 | uint32_t hashline; |
| 146 | |
| 147 | if (dirh == NULL) |
| 148 | return; |
| 149 | |
| 150 | if (dirh->size == 0) |
| 151 | return; |
| 152 | |
| 153 | for (hashline = 0; hashline < DIRHASH_HASHSIZE; hashline++) { |
| 154 | while ((dirh_e = |
| 155 | LIST_FIRST(&dirh->entries[hashline])) != NULL) { |
| 156 | LIST_REMOVE(dirh_e, next); |
| 157 | pool_put(&dirhash_entry_pool, dirh_e); |
| 158 | } |
| 159 | } |
| 160 | |
| 161 | while ((dirh_e = LIST_FIRST(&dirh->free_entries)) != NULL) { |
| 162 | LIST_REMOVE(dirh_e, next); |
| 163 | pool_put(&dirhash_entry_pool, dirh_e); |
| 164 | } |
| 165 | |
| 166 | dirh->flags &= ~DIRH_COMPLETE; |
| 167 | dirh->flags |= DIRH_PURGED; |
| 168 | dirh->num_files = 0; |
| 169 | |
| 170 | dirhashsize -= dirh->size; |
| 171 | dirh->size = 0; |
| 172 | } |
| 173 | |
| 174 | |
| 175 | void |
| 176 | dirhash_purge(struct dirhash **dirhp) |
| 177 | { |
| 178 | struct dirhash *dirh = *dirhp; |
| 179 | |
| 180 | if (dirh == NULL) |
| 181 | return; |
| 182 | |
| 183 | /* purge its entries */ |
| 184 | dirhash_purge_entries(dirh); |
| 185 | |
| 186 | /* recycle */ |
| 187 | mutex_enter(&dirhashmutex); |
| 188 | TAILQ_REMOVE(&dirhash_queue, dirh, next); |
| 189 | mutex_exit(&dirhashmutex); |
| 190 | |
| 191 | pool_put(&dirhash_pool, dirh); |
| 192 | *dirhp = NULL; |
| 193 | } |
| 194 | |
| 195 | |
| 196 | void |
| 197 | dirhash_get(struct dirhash **dirhp) |
| 198 | { |
| 199 | struct dirhash *dirh; |
| 200 | uint32_t hashline; |
| 201 | |
| 202 | /* if no dirhash was given, allocate one */ |
| 203 | dirh = *dirhp; |
| 204 | if (dirh == NULL) { |
| 205 | dirh = pool_get(&dirhash_pool, PR_WAITOK); |
| 206 | memset(dirh, 0, sizeof(struct dirhash)); |
| 207 | for (hashline = 0; hashline < DIRHASH_HASHSIZE; hashline++) { |
| 208 | LIST_INIT(&dirh->entries[hashline]); |
| 209 | } |
| 210 | } |
| 211 | |
| 212 | /* implement LRU on the dirhash queue */ |
| 213 | mutex_enter(&dirhashmutex); |
| 214 | if (*dirhp) { |
| 215 | /* remove from queue to be requeued */ |
| 216 | TAILQ_REMOVE(&dirhash_queue, dirh, next); |
| 217 | } |
| 218 | dirh->refcnt++; |
| 219 | TAILQ_INSERT_HEAD(&dirhash_queue, dirh, next); |
| 220 | mutex_exit(&dirhashmutex); |
| 221 | |
| 222 | *dirhp = dirh; |
| 223 | } |
| 224 | |
| 225 | |
| 226 | void |
| 227 | dirhash_put(struct dirhash *dirh) |
| 228 | { |
| 229 | |
| 230 | mutex_enter(&dirhashmutex); |
| 231 | dirh->refcnt--; |
| 232 | mutex_exit(&dirhashmutex); |
| 233 | } |
| 234 | |
| 235 | |
| 236 | void |
| 237 | dirhash_enter(struct dirhash *dirh, |
| 238 | struct dirent *dirent, uint64_t offset, uint32_t entry_size, int new_p) |
| 239 | { |
| 240 | struct dirhash *del_dirh, *prev_dirh; |
| 241 | struct dirhash_entry *dirh_e; |
| 242 | uint32_t hashvalue, hashline; |
| 243 | int entrysize; |
| 244 | |
| 245 | /* make sure we have a dirhash to work on */ |
| 246 | KASSERT(dirh); |
| 247 | KASSERT(dirh->refcnt > 0); |
| 248 | |
| 249 | /* are we trying to re-enter an entry? */ |
| 250 | if (!new_p && (dirh->flags & DIRH_COMPLETE)) |
| 251 | return; |
| 252 | |
| 253 | /* calculate our hash */ |
| 254 | hashvalue = hash32_strn(dirent->d_name, dirent->d_namlen, HASH32_STR_INIT); |
| 255 | hashline = hashvalue & DIRHASH_HASHMASK; |
| 256 | |
| 257 | /* lookup and insert entry if not there yet */ |
| 258 | LIST_FOREACH(dirh_e, &dirh->entries[hashline], next) { |
| 259 | /* check for hash collision */ |
| 260 | if (dirh_e->hashvalue != hashvalue) |
| 261 | continue; |
| 262 | if (dirh_e->offset != offset) |
| 263 | continue; |
| 264 | /* got it already */ |
| 265 | KASSERT(dirh_e->d_namlen == dirent->d_namlen); |
| 266 | KASSERT(dirh_e->entry_size == entry_size); |
| 267 | return; |
| 268 | } |
| 269 | |
| 270 | DPRINTF(("dirhash enter %" PRIu64", %d, %d for `%*.*s`\n" , |
| 271 | offset, entry_size, dirent->d_namlen, |
| 272 | dirent->d_namlen, dirent->d_namlen, dirent->d_name)); |
| 273 | |
| 274 | /* check if entry is in free space list */ |
| 275 | LIST_FOREACH(dirh_e, &dirh->free_entries, next) { |
| 276 | if (dirh_e->offset == offset) { |
| 277 | DPRINTF(("\tremoving free entry\n" )); |
| 278 | LIST_REMOVE(dirh_e, next); |
| 279 | pool_put(&dirhash_entry_pool, dirh_e); |
| 280 | break; |
| 281 | } |
| 282 | } |
| 283 | |
| 284 | /* ensure we are not passing the dirhash limit */ |
| 285 | entrysize = sizeof(struct dirhash_entry); |
| 286 | if (dirhashsize + entrysize > maxdirhashsize) { |
| 287 | /* we walk the dirhash_queue, so need to lock it */ |
| 288 | mutex_enter(&dirhashmutex); |
| 289 | del_dirh = TAILQ_LAST(&dirhash_queue, _dirhash); |
| 290 | KASSERT(del_dirh); |
| 291 | while (dirhashsize + entrysize > maxdirhashsize) { |
| 292 | /* no use trying to delete myself */ |
| 293 | if (del_dirh == dirh) |
| 294 | break; |
| 295 | prev_dirh = TAILQ_PREV(del_dirh, _dirhash, next); |
| 296 | if (del_dirh->refcnt == 0) |
| 297 | dirhash_purge_entries(del_dirh); |
| 298 | del_dirh = prev_dirh; |
| 299 | } |
| 300 | mutex_exit(&dirhashmutex); |
| 301 | } |
| 302 | |
| 303 | /* add to the hashline */ |
| 304 | dirh_e = pool_get(&dirhash_entry_pool, PR_WAITOK); |
| 305 | memset(dirh_e, 0, sizeof(struct dirhash_entry)); |
| 306 | |
| 307 | dirh_e->hashvalue = hashvalue; |
| 308 | dirh_e->offset = offset; |
| 309 | dirh_e->d_namlen = dirent->d_namlen; |
| 310 | dirh_e->entry_size = entry_size; |
| 311 | |
| 312 | dirh->size += sizeof(struct dirhash_entry); |
| 313 | dirh->num_files++; |
| 314 | dirhashsize += sizeof(struct dirhash_entry); |
| 315 | LIST_INSERT_HEAD(&dirh->entries[hashline], dirh_e, next); |
| 316 | } |
| 317 | |
| 318 | |
| 319 | void |
| 320 | dirhash_enter_freed(struct dirhash *dirh, uint64_t offset, |
| 321 | uint32_t entry_size) |
| 322 | { |
| 323 | struct dirhash_entry *dirh_e; |
| 324 | |
| 325 | /* make sure we have a dirhash to work on */ |
| 326 | KASSERT(dirh); |
| 327 | KASSERT(dirh->refcnt > 0); |
| 328 | |
| 329 | /* check for double entry of free space */ |
| 330 | LIST_FOREACH(dirh_e, &dirh->free_entries, next) { |
| 331 | KASSERT(dirh_e->offset != offset); |
| 332 | } |
| 333 | |
| 334 | DPRINTF(("dirhash enter FREED %" PRIu64", %d\n" , |
| 335 | offset, entry_size)); |
| 336 | dirh_e = pool_get(&dirhash_entry_pool, PR_WAITOK); |
| 337 | memset(dirh_e, 0, sizeof(struct dirhash_entry)); |
| 338 | |
| 339 | dirh_e->hashvalue = 0; /* not relevant */ |
| 340 | dirh_e->offset = offset; |
| 341 | dirh_e->d_namlen = 0; /* not relevant */ |
| 342 | dirh_e->entry_size = entry_size; |
| 343 | |
| 344 | /* XXX it might be preferable to append them at the tail */ |
| 345 | LIST_INSERT_HEAD(&dirh->free_entries, dirh_e, next); |
| 346 | dirh->size += sizeof(struct dirhash_entry); |
| 347 | dirhashsize += sizeof(struct dirhash_entry); |
| 348 | } |
| 349 | |
| 350 | |
| 351 | void |
| 352 | dirhash_remove(struct dirhash *dirh, struct dirent *dirent, |
| 353 | uint64_t offset, uint32_t entry_size) |
| 354 | { |
| 355 | struct dirhash_entry *dirh_e; |
| 356 | uint32_t hashvalue, hashline; |
| 357 | |
| 358 | DPRINTF(("dirhash remove %" PRIu64", %d for `%*.*s`\n" , |
| 359 | offset, entry_size, |
| 360 | dirent->d_namlen, dirent->d_namlen, dirent->d_name)); |
| 361 | |
| 362 | /* make sure we have a dirhash to work on */ |
| 363 | KASSERT(dirh); |
| 364 | KASSERT(dirh->refcnt > 0); |
| 365 | |
| 366 | /* calculate our hash */ |
| 367 | hashvalue = hash32_strn(dirent->d_name, dirent->d_namlen, HASH32_STR_INIT); |
| 368 | hashline = hashvalue & DIRHASH_HASHMASK; |
| 369 | |
| 370 | /* lookup entry */ |
| 371 | LIST_FOREACH(dirh_e, &dirh->entries[hashline], next) { |
| 372 | /* check for hash collision */ |
| 373 | if (dirh_e->hashvalue != hashvalue) |
| 374 | continue; |
| 375 | if (dirh_e->offset != offset) |
| 376 | continue; |
| 377 | |
| 378 | /* got it! */ |
| 379 | KASSERT(dirh_e->d_namlen == dirent->d_namlen); |
| 380 | KASSERT(dirh_e->entry_size == entry_size); |
| 381 | LIST_REMOVE(dirh_e, next); |
| 382 | dirh->size -= sizeof(struct dirhash_entry); |
| 383 | KASSERT(dirh->num_files > 0); |
| 384 | dirh->num_files--; |
| 385 | dirhashsize -= sizeof(struct dirhash_entry); |
| 386 | |
| 387 | dirhash_enter_freed(dirh, offset, entry_size); |
| 388 | return; |
| 389 | } |
| 390 | |
| 391 | /* not found! */ |
| 392 | panic("dirhash_remove couldn't find entry in hash table\n" ); |
| 393 | } |
| 394 | |
| 395 | |
| 396 | /* |
| 397 | * BUGALERT: don't use result longer than needed, never past the node lock. |
| 398 | * Call with NULL *result initially and it will return nonzero if again. |
| 399 | */ |
| 400 | int |
| 401 | dirhash_lookup(struct dirhash *dirh, const char *d_name, int d_namlen, |
| 402 | struct dirhash_entry **result) |
| 403 | { |
| 404 | struct dirhash_entry *dirh_e; |
| 405 | uint32_t hashvalue, hashline; |
| 406 | |
| 407 | /* make sure we have a dirhash to work on */ |
| 408 | KASSERT(dirh); |
| 409 | KASSERT(dirh->refcnt > 0); |
| 410 | |
| 411 | /* start where we were */ |
| 412 | if (*result) { |
| 413 | dirh_e = *result; |
| 414 | |
| 415 | /* retrieve information to avoid recalculation and advance */ |
| 416 | hashvalue = dirh_e->hashvalue; |
| 417 | dirh_e = LIST_NEXT(*result, next); |
| 418 | } else { |
| 419 | /* calculate our hash and lookup all entries in hashline */ |
| 420 | hashvalue = hash32_strn(d_name, d_namlen, HASH32_STR_INIT); |
| 421 | hashline = hashvalue & DIRHASH_HASHMASK; |
| 422 | dirh_e = LIST_FIRST(&dirh->entries[hashline]); |
| 423 | } |
| 424 | |
| 425 | for (; dirh_e; dirh_e = LIST_NEXT(dirh_e, next)) { |
| 426 | /* check for hash collision */ |
| 427 | if (dirh_e->hashvalue != hashvalue) |
| 428 | continue; |
| 429 | if (dirh_e->d_namlen != d_namlen) |
| 430 | continue; |
| 431 | /* might have an entry in the cache */ |
| 432 | *result = dirh_e; |
| 433 | return 1; |
| 434 | } |
| 435 | |
| 436 | *result = NULL; |
| 437 | return 0; |
| 438 | } |
| 439 | |
| 440 | |
| 441 | /* |
| 442 | * BUGALERT: don't use result longer than needed, never past the node lock. |
| 443 | * Call with NULL *result initially and it will return nonzero if again. |
| 444 | */ |
| 445 | |
| 446 | int |
| 447 | dirhash_lookup_freed(struct dirhash *dirh, uint32_t min_entrysize, |
| 448 | struct dirhash_entry **result) |
| 449 | { |
| 450 | struct dirhash_entry *dirh_e; |
| 451 | |
| 452 | /* make sure we have a dirhash to work on */ |
| 453 | KASSERT(dirh); |
| 454 | KASSERT(dirh->refcnt > 0); |
| 455 | |
| 456 | /* start where we were */ |
| 457 | if (*result) { |
| 458 | dirh_e = LIST_NEXT(*result, next); |
| 459 | } else { |
| 460 | /* lookup all entries that match */ |
| 461 | dirh_e = LIST_FIRST(&dirh->free_entries); |
| 462 | } |
| 463 | |
| 464 | for (; dirh_e; dirh_e = LIST_NEXT(dirh_e, next)) { |
| 465 | /* check for minimum size */ |
| 466 | if (dirh_e->entry_size < min_entrysize) |
| 467 | continue; |
| 468 | /* might be a candidate */ |
| 469 | *result = dirh_e; |
| 470 | return 1; |
| 471 | } |
| 472 | |
| 473 | *result = NULL; |
| 474 | return 0; |
| 475 | } |
| 476 | |
| 477 | |
| 478 | bool |
| 479 | dirhash_dir_isempty(struct dirhash *dirh) |
| 480 | { |
| 481 | #ifdef DEBUG |
| 482 | struct dirhash_entry *dirh_e; |
| 483 | int hashline, num; |
| 484 | |
| 485 | num = 0; |
| 486 | for (hashline = 0; hashline < DIRHASH_HASHSIZE; hashline++) { |
| 487 | LIST_FOREACH(dirh_e, &dirh->entries[hashline], next) { |
| 488 | num++; |
| 489 | } |
| 490 | } |
| 491 | |
| 492 | if (dirh->num_files != num) { |
| 493 | printf("dirhash_dir_isempy: dirhash_counter failed: " |
| 494 | "dirh->num_files = %d, counted %d\n" , |
| 495 | dirh->num_files, num); |
| 496 | assert(dirh->num_files == num); |
| 497 | } |
| 498 | #endif |
| 499 | /* assert the directory hash info is valid */ |
| 500 | KASSERT(dirh->flags & DIRH_COMPLETE); |
| 501 | |
| 502 | /* the directory is empty when only '..' lifes in it or is absent */ |
| 503 | return (dirh->num_files <= 1); |
| 504 | } |
| 505 | |
| 506 | |