| 1 | /* $NetBSD: coda_namecache.c,v 1.26 2014/10/18 08:33:27 snj Exp $ */ |
| 2 | |
| 3 | /* |
| 4 | * |
| 5 | * Coda: an Experimental Distributed File System |
| 6 | * Release 3.1 |
| 7 | * |
| 8 | * Copyright (c) 1987-1998 Carnegie Mellon University |
| 9 | * All Rights Reserved |
| 10 | * |
| 11 | * Permission to use, copy, modify and distribute this software and its |
| 12 | * documentation is hereby granted, provided that both the copyright |
| 13 | * notice and this permission notice appear in all copies of the |
| 14 | * software, derivative works or modified versions, and any portions |
| 15 | * thereof, and that both notices appear in supporting documentation, and |
| 16 | * that credit is given to Carnegie Mellon University in all documents |
| 17 | * and publicity pertaining to direct or indirect use of this code or its |
| 18 | * derivatives. |
| 19 | * |
| 20 | * CODA IS AN EXPERIMENTAL SOFTWARE SYSTEM AND IS KNOWN TO HAVE BUGS, |
| 21 | * SOME OF WHICH MAY HAVE SERIOUS CONSEQUENCES. CARNEGIE MELLON ALLOWS |
| 22 | * FREE USE OF THIS SOFTWARE IN ITS "AS IS" CONDITION. CARNEGIE MELLON |
| 23 | * DISCLAIMS ANY LIABILITY OF ANY KIND FOR ANY DAMAGES WHATSOEVER |
| 24 | * RESULTING DIRECTLY OR INDIRECTLY FROM THE USE OF THIS SOFTWARE OR OF |
| 25 | * ANY DERIVATIVE WORK. |
| 26 | * |
| 27 | * Carnegie Mellon encourages users of this software to return any |
| 28 | * improvements or extensions that they make, and to grant Carnegie |
| 29 | * Mellon the rights to redistribute these changes without encumbrance. |
| 30 | * |
| 31 | * @(#) coda/coda_namecache.c,v 1.1.1.1 1998/08/29 21:26:45 rvb Exp $ |
| 32 | */ |
| 33 | |
| 34 | /* |
| 35 | * Mach Operating System |
| 36 | * Copyright (c) 1990 Carnegie-Mellon University |
| 37 | * Copyright (c) 1989 Carnegie-Mellon University |
| 38 | * All rights reserved. The CMU software License Agreement specifies |
| 39 | * the terms and conditions for use and redistribution. |
| 40 | */ |
| 41 | |
| 42 | /* |
| 43 | * This code was written for the Coda file system at Carnegie Mellon University. |
| 44 | * Contributers include David Steere, James Kistler, and M. Satyanarayanan. |
| 45 | */ |
| 46 | |
| 47 | /* |
| 48 | * This module contains the routines to implement the CODA name cache. The |
| 49 | * purpose of this cache is to reduce the cost of translating pathnames |
| 50 | * into Vice FIDs. Each entry in the cache contains the name of the file, |
| 51 | * the vnode (FID) of the parent directory, and the cred structure of the |
| 52 | * user accessing the file. |
| 53 | * |
| 54 | * The first time a file is accessed, it is looked up by the local Venus |
| 55 | * which first insures that the user has access to the file. In addition |
| 56 | * we are guaranteed that Venus will invalidate any name cache entries in |
| 57 | * case the user no longer should be able to access the file. For these |
| 58 | * reasons we do not need to keep access list information as well as a |
| 59 | * cred structure for each entry. |
| 60 | * |
| 61 | * The table can be accessed through the routines cnc_init(), cnc_enter(), |
| 62 | * cnc_lookup(), cnc_rmfidcred(), cnc_rmfid(), cnc_rmcred(), and cnc_purge(). |
| 63 | * There are several other routines which aid in the implementation of the |
| 64 | * hash table. |
| 65 | */ |
| 66 | |
| 67 | /* |
| 68 | * NOTES: rvb@cs |
| 69 | * 1. The name cache holds a reference to every vnode in it. Hence files can not be |
| 70 | * closed or made inactive until they are released. |
| 71 | * 2. coda_nc_name(cp) was added to get a name for a cnode pointer for debugging. |
| 72 | * 3. coda_nc_find() has debug code to detect when entries are stored with different |
| 73 | * credentials. We don't understand yet, if/how entries are NOT EQ but still |
| 74 | * EQUAL |
| 75 | * 4. I wonder if this name cache could be replace by the vnode name cache. |
| 76 | * The latter has no zapping functions, so probably not. |
| 77 | */ |
| 78 | |
| 79 | #include <sys/cdefs.h> |
| 80 | __KERNEL_RCSID(0, "$NetBSD: coda_namecache.c,v 1.26 2014/10/18 08:33:27 snj Exp $" ); |
| 81 | |
| 82 | #include <sys/param.h> |
| 83 | #include <sys/errno.h> |
| 84 | #include <sys/malloc.h> |
| 85 | #include <sys/select.h> |
| 86 | #include <sys/kauth.h> |
| 87 | |
| 88 | #include <coda/coda.h> |
| 89 | #include <coda/cnode.h> |
| 90 | #include <coda/coda_namecache.h> |
| 91 | #include <coda/coda_subr.h> |
| 92 | |
| 93 | /* |
| 94 | * Declaration of the name cache data structure. |
| 95 | */ |
| 96 | |
| 97 | int coda_nc_use = 1; /* Indicate use of CODA Name Cache */ |
| 98 | |
| 99 | int coda_nc_size = CODA_NC_CACHESIZE; /* size of the cache */ |
| 100 | int coda_nc_hashsize = CODA_NC_HASHSIZE; /* size of the primary hash */ |
| 101 | |
| 102 | struct coda_cache *coda_nc_heap; /* pointer to the cache entries */ |
| 103 | struct coda_hash *coda_nc_hash; /* hash table of cfscache pointers */ |
| 104 | struct coda_lru coda_nc_lru; /* head of lru chain */ |
| 105 | |
| 106 | struct coda_nc_statistics coda_nc_stat; /* Keep various stats */ |
| 107 | |
| 108 | /* |
| 109 | * for testing purposes |
| 110 | */ |
| 111 | int coda_nc_debug = 0; |
| 112 | |
| 113 | /* |
| 114 | * Entry points for the CODA Name Cache |
| 115 | */ |
| 116 | static struct coda_cache * |
| 117 | coda_nc_find(struct cnode *dcp, const char *name, int namelen, |
| 118 | kauth_cred_t cred, int hash); |
| 119 | static void |
| 120 | coda_nc_remove(struct coda_cache *cncp, enum dc_status dcstat); |
| 121 | |
| 122 | /* |
| 123 | * Initialize the cache, the LRU structure and the Hash structure(s) |
| 124 | */ |
| 125 | |
| 126 | #define TOTAL_CACHE_SIZE (sizeof(struct coda_cache) * coda_nc_size) |
| 127 | #define TOTAL_HASH_SIZE (sizeof(struct coda_hash) * coda_nc_hashsize) |
| 128 | |
| 129 | int coda_nc_initialized = 0; /* Initially the cache has not been initialized */ |
| 130 | |
| 131 | void |
| 132 | coda_nc_init(void) |
| 133 | { |
| 134 | int i; |
| 135 | |
| 136 | /* zero the statistics structure */ |
| 137 | |
| 138 | memset(&coda_nc_stat, 0, (sizeof(struct coda_nc_statistics))); |
| 139 | |
| 140 | #ifdef CODA_VERBOSE |
| 141 | printf("CODA NAME CACHE: CACHE %d, HASH TBL %d\n" , CODA_NC_CACHESIZE, CODA_NC_HASHSIZE); |
| 142 | #endif |
| 143 | CODA_ALLOC(coda_nc_heap, struct coda_cache *, TOTAL_CACHE_SIZE); |
| 144 | CODA_ALLOC(coda_nc_hash, struct coda_hash *, TOTAL_HASH_SIZE); |
| 145 | |
| 146 | memset(coda_nc_heap, 0, TOTAL_CACHE_SIZE); |
| 147 | memset(coda_nc_hash, 0, TOTAL_HASH_SIZE); |
| 148 | |
| 149 | TAILQ_INIT(&coda_nc_lru.head); |
| 150 | |
| 151 | for (i=0; i < coda_nc_size; i++) { /* initialize the heap */ |
| 152 | TAILQ_INSERT_HEAD(&coda_nc_lru.head, &coda_nc_heap[i], lru); |
| 153 | } |
| 154 | |
| 155 | for (i=0; i < coda_nc_hashsize; i++) { /* initialize the hashtable */ |
| 156 | LIST_INIT(&coda_nc_hash[i].head); |
| 157 | } |
| 158 | |
| 159 | coda_nc_initialized++; |
| 160 | } |
| 161 | |
| 162 | /* |
| 163 | * Auxillary routines -- shouldn't be entry points |
| 164 | */ |
| 165 | |
| 166 | static struct coda_cache * |
| 167 | coda_nc_find(struct cnode *dcp, const char *name, int namelen, |
| 168 | kauth_cred_t cred, int hash) |
| 169 | { |
| 170 | /* |
| 171 | * hash to find the appropriate bucket, look through the chain |
| 172 | * for the right entry (especially right cred, unless cred == 0) |
| 173 | */ |
| 174 | struct coda_cache *cncp; |
| 175 | int count = 1; |
| 176 | |
| 177 | CODA_NC_DEBUG(CODA_NC_FIND, |
| 178 | myprintf(("coda_nc_find(dcp %p, name %s, len %d, cred %p, hash %d\n" , |
| 179 | dcp, name, namelen, cred, hash));) |
| 180 | |
| 181 | LIST_FOREACH(cncp, &coda_nc_hash[hash].head, hash) |
| 182 | { |
| 183 | |
| 184 | if ((CODA_NAMEMATCH(cncp, name, namelen, dcp)) && |
| 185 | ((cred == 0) || (cncp->cred == cred))) |
| 186 | { |
| 187 | /* compare cr_uid instead */ |
| 188 | coda_nc_stat.Search_len += count; |
| 189 | return(cncp); |
| 190 | } |
| 191 | #ifdef DEBUG |
| 192 | else if (CODA_NAMEMATCH(cncp, name, namelen, dcp)) { |
| 193 | printf("coda_nc_find: name %s, new cred = %p, cred = %p\n" , |
| 194 | name, cred, cncp->cred); |
| 195 | printf("nref %d, nuid %d, ngid %d // oref %d, ocred %d, ogid %d\n" , |
| 196 | kauth_cred_getrefcnt(cred), |
| 197 | kauth_cred_geteuid(cred), |
| 198 | kauth_cred_getegid(cred), |
| 199 | kauth_cred_getrefcnt(cncp->cred), |
| 200 | kauth_cred_geteuid(cncp->cred), |
| 201 | kauth_cred_getegid(cncp->cred)); |
| 202 | coda_print_cred(cred); |
| 203 | coda_print_cred(cncp->cred); |
| 204 | } |
| 205 | #endif |
| 206 | count++; |
| 207 | } |
| 208 | |
| 209 | return((struct coda_cache *)0); |
| 210 | } |
| 211 | |
| 212 | /* |
| 213 | * Enter a new (dir cnode, name) pair into the cache, updating the |
| 214 | * LRU and Hash as needed. |
| 215 | */ |
| 216 | void |
| 217 | coda_nc_enter(struct cnode *dcp, const char *name, int namelen, |
| 218 | kauth_cred_t cred, struct cnode *cp) |
| 219 | { |
| 220 | struct coda_cache *cncp; |
| 221 | int hash; |
| 222 | |
| 223 | if (coda_nc_use == 0) /* Cache is off */ |
| 224 | return; |
| 225 | |
| 226 | CODA_NC_DEBUG(CODA_NC_ENTER, |
| 227 | myprintf(("Enter: dcp %p cp %p name %s cred %p \n" , |
| 228 | dcp, cp, name, cred)); ) |
| 229 | |
| 230 | if (namelen > CODA_NC_NAMELEN) { |
| 231 | CODA_NC_DEBUG(CODA_NC_ENTER, |
| 232 | myprintf(("long name enter %s\n" ,name));) |
| 233 | coda_nc_stat.long_name_enters++; /* record stats */ |
| 234 | return; |
| 235 | } |
| 236 | |
| 237 | hash = CODA_NC_HASH(name, namelen, dcp); |
| 238 | cncp = coda_nc_find(dcp, name, namelen, cred, hash); |
| 239 | if (cncp != (struct coda_cache *) 0) { |
| 240 | coda_nc_stat.dbl_enters++; /* duplicate entry */ |
| 241 | return; |
| 242 | } |
| 243 | |
| 244 | coda_nc_stat.enters++; /* record the enters statistic */ |
| 245 | |
| 246 | /* Grab the next element in the lru chain */ |
| 247 | cncp = TAILQ_FIRST(&coda_nc_lru.head); |
| 248 | TAILQ_REMOVE(&coda_nc_lru.head, cncp, lru); |
| 249 | |
| 250 | if (CODA_NC_VALID(cncp)) { |
| 251 | /* Seems really ugly, but we have to decrement the appropriate |
| 252 | hash bucket length here, so we have to find the hash bucket |
| 253 | */ |
| 254 | coda_nc_hash[CODA_NC_HASH(cncp->name, cncp->namelen, cncp->dcp)].length--; |
| 255 | |
| 256 | coda_nc_stat.lru_rm++; /* zapped a valid entry */ |
| 257 | LIST_REMOVE(cncp, hash); |
| 258 | vrele(CTOV(cncp->dcp)); |
| 259 | vrele(CTOV(cncp->cp)); |
| 260 | kauth_cred_free(cncp->cred); |
| 261 | } |
| 262 | |
| 263 | /* |
| 264 | * Put a hold on the current vnodes and fill in the cache entry. |
| 265 | */ |
| 266 | vref(CTOV(cp)); |
| 267 | vref(CTOV(dcp)); |
| 268 | kauth_cred_hold(cred); |
| 269 | cncp->dcp = dcp; |
| 270 | cncp->cp = cp; |
| 271 | cncp->namelen = namelen; |
| 272 | cncp->cred = cred; |
| 273 | |
| 274 | memcpy(cncp->name, name, (unsigned)namelen); |
| 275 | |
| 276 | /* Insert into the lru and hash chains. */ |
| 277 | TAILQ_INSERT_TAIL(&coda_nc_lru.head, cncp, lru); |
| 278 | LIST_INSERT_HEAD(&coda_nc_hash[hash].head, cncp, hash); |
| 279 | coda_nc_hash[hash].length++; /* Used for tuning */ |
| 280 | |
| 281 | CODA_NC_DEBUG(CODA_NC_PRINTCODA_NC, print_coda_nc(); ) |
| 282 | } |
| 283 | |
| 284 | /* |
| 285 | * Find the (dir cnode, name) pair in the cache, if its cred |
| 286 | * matches the input, return it, otherwise return 0 |
| 287 | */ |
| 288 | struct cnode * |
| 289 | coda_nc_lookup(struct cnode *dcp, const char *name, int namelen, |
| 290 | kauth_cred_t cred) |
| 291 | { |
| 292 | int hash; |
| 293 | struct coda_cache *cncp; |
| 294 | |
| 295 | if (coda_nc_use == 0) /* Cache is off */ |
| 296 | return((struct cnode *) 0); |
| 297 | |
| 298 | if (namelen > CODA_NC_NAMELEN) { |
| 299 | CODA_NC_DEBUG(CODA_NC_LOOKUP, |
| 300 | myprintf(("long name lookup %s\n" ,name));) |
| 301 | coda_nc_stat.long_name_lookups++; /* record stats */ |
| 302 | return((struct cnode *) 0); |
| 303 | } |
| 304 | |
| 305 | /* Use the hash function to locate the starting point, |
| 306 | then the search routine to go down the list looking for |
| 307 | the correct cred. |
| 308 | */ |
| 309 | |
| 310 | hash = CODA_NC_HASH(name, namelen, dcp); |
| 311 | cncp = coda_nc_find(dcp, name, namelen, cred, hash); |
| 312 | if (cncp == (struct coda_cache *) 0) { |
| 313 | coda_nc_stat.misses++; /* record miss */ |
| 314 | return((struct cnode *) 0); |
| 315 | } |
| 316 | |
| 317 | coda_nc_stat.hits++; |
| 318 | |
| 319 | /* put this entry at the end of the LRU */ |
| 320 | TAILQ_REMOVE(&coda_nc_lru.head, cncp, lru); |
| 321 | TAILQ_INSERT_TAIL(&coda_nc_lru.head, cncp, lru); |
| 322 | |
| 323 | /* move it to the front of the hash chain */ |
| 324 | /* don't need to change the hash bucket length */ |
| 325 | LIST_REMOVE(cncp, hash); |
| 326 | LIST_INSERT_HEAD(&coda_nc_hash[hash].head, cncp, hash); |
| 327 | |
| 328 | CODA_NC_DEBUG(CODA_NC_LOOKUP, |
| 329 | printf("lookup: dcp %p, name %s, cred %p = cp %p\n" , |
| 330 | dcp, name, cred, cncp->cp); ) |
| 331 | |
| 332 | return(cncp->cp); |
| 333 | } |
| 334 | |
| 335 | static void |
| 336 | coda_nc_remove(struct coda_cache *cncp, enum dc_status dcstat) |
| 337 | { |
| 338 | /* |
| 339 | * remove an entry -- vrele(cncp->dcp, cp), crfree(cred), |
| 340 | * remove it from its hash chain, and |
| 341 | * place it at the head of the lru list. |
| 342 | */ |
| 343 | CODA_NC_DEBUG(CODA_NC_REMOVE, |
| 344 | myprintf(("coda_nc_remove %s from parent %s\n" , |
| 345 | cncp->name, coda_f2s(&cncp->dcp->c_fid))); ) |
| 346 | |
| 347 | |
| 348 | LIST_REMOVE(cncp, hash); |
| 349 | memset(&cncp->hash, 0, sizeof(cncp->hash)); |
| 350 | |
| 351 | if ((dcstat == IS_DOWNCALL) && (CTOV(cncp->dcp)->v_usecount == 1)) { |
| 352 | cncp->dcp->c_flags |= C_PURGING; |
| 353 | } |
| 354 | vrele(CTOV(cncp->dcp)); |
| 355 | |
| 356 | if ((dcstat == IS_DOWNCALL) && (CTOV(cncp->cp)->v_usecount == 1)) { |
| 357 | cncp->cp->c_flags |= C_PURGING; |
| 358 | } |
| 359 | vrele(CTOV(cncp->cp)); |
| 360 | |
| 361 | kauth_cred_free(cncp->cred); |
| 362 | memset(DATA_PART(cncp), 0, DATA_SIZE); |
| 363 | |
| 364 | /* move the null entry to the front for reuse */ |
| 365 | TAILQ_REMOVE(&coda_nc_lru.head, cncp, lru); |
| 366 | TAILQ_INSERT_HEAD(&coda_nc_lru.head, cncp, lru); |
| 367 | } |
| 368 | |
| 369 | /* |
| 370 | * Remove all entries with a parent which has the input fid. |
| 371 | */ |
| 372 | void |
| 373 | coda_nc_zapParentfid(CodaFid *fid, enum dc_status dcstat) |
| 374 | { |
| 375 | /* To get to a specific fid, we might either have another hashing |
| 376 | function or do a sequential search through the cache for the |
| 377 | appropriate entries. The later may be acceptable since I don't |
| 378 | think callbacks or whatever Case 1 covers are frequent occurrences. |
| 379 | */ |
| 380 | struct coda_cache *cncp, *ncncp; |
| 381 | int i; |
| 382 | |
| 383 | if (coda_nc_use == 0) /* Cache is off */ |
| 384 | return; |
| 385 | |
| 386 | CODA_NC_DEBUG(CODA_NC_ZAPPFID, |
| 387 | myprintf(("ZapParent: fid %s\n" , coda_f2s(fid))); ) |
| 388 | |
| 389 | coda_nc_stat.zapPfids++; |
| 390 | |
| 391 | for (i = 0; i < coda_nc_hashsize; i++) { |
| 392 | |
| 393 | /* |
| 394 | * Need to save the hash_next pointer in case we remove the |
| 395 | * entry. remove causes hash_next to point to itself. |
| 396 | */ |
| 397 | |
| 398 | ncncp = LIST_FIRST(&coda_nc_hash[i].head); |
| 399 | while ((cncp = ncncp) != NULL) { |
| 400 | ncncp = LIST_NEXT(cncp, hash); |
| 401 | |
| 402 | if (coda_fid_eq(&(cncp->dcp->c_fid), fid)) { |
| 403 | coda_nc_hash[i].length--; /* Used for tuning */ |
| 404 | coda_nc_remove(cncp, dcstat); |
| 405 | } |
| 406 | } |
| 407 | } |
| 408 | } |
| 409 | |
| 410 | /* |
| 411 | * Remove all entries which have the same fid as the input |
| 412 | */ |
| 413 | void |
| 414 | coda_nc_zapfid(CodaFid *fid, enum dc_status dcstat) |
| 415 | { |
| 416 | /* See comment for zapParentfid. This routine will be used |
| 417 | if attributes are being cached. |
| 418 | */ |
| 419 | struct coda_cache *cncp, *ncncp; |
| 420 | int i; |
| 421 | |
| 422 | if (coda_nc_use == 0) /* Cache is off */ |
| 423 | return; |
| 424 | |
| 425 | CODA_NC_DEBUG(CODA_NC_ZAPFID, |
| 426 | myprintf(("Zapfid: fid %s\n" , coda_f2s(fid))); ) |
| 427 | |
| 428 | coda_nc_stat.zapFids++; |
| 429 | |
| 430 | for (i = 0; i < coda_nc_hashsize; i++) { |
| 431 | |
| 432 | ncncp = LIST_FIRST(&coda_nc_hash[i].head); |
| 433 | while ((cncp = ncncp) != NULL) { |
| 434 | ncncp = LIST_NEXT(cncp, hash); |
| 435 | |
| 436 | if (coda_fid_eq(&cncp->cp->c_fid, fid)) { |
| 437 | coda_nc_hash[i].length--; /* Used for tuning */ |
| 438 | coda_nc_remove(cncp, dcstat); |
| 439 | } |
| 440 | } |
| 441 | } |
| 442 | } |
| 443 | |
| 444 | /* |
| 445 | * Remove all entries which match the fid and the cred |
| 446 | */ |
| 447 | void |
| 448 | coda_nc_zapvnode(CodaFid *fid, kauth_cred_t cred, |
| 449 | enum dc_status dcstat) |
| 450 | { |
| 451 | /* See comment for zapfid. I don't think that one would ever |
| 452 | want to zap a file with a specific cred from the kernel. |
| 453 | We'll leave this one unimplemented. |
| 454 | */ |
| 455 | if (coda_nc_use == 0) /* Cache is off */ |
| 456 | return; |
| 457 | |
| 458 | CODA_NC_DEBUG(CODA_NC_ZAPVNODE, |
| 459 | myprintf(("Zapvnode: fid %s cred %p\n" , |
| 460 | coda_f2s(fid), cred)); ) |
| 461 | } |
| 462 | |
| 463 | /* |
| 464 | * Remove all entries which have the (dir vnode, name) pair |
| 465 | */ |
| 466 | void |
| 467 | coda_nc_zapfile(struct cnode *dcp, const char *name, int namelen) |
| 468 | { |
| 469 | /* use the hash function to locate the file, then zap all |
| 470 | entries of it regardless of the cred. |
| 471 | */ |
| 472 | struct coda_cache *cncp; |
| 473 | int hash; |
| 474 | |
| 475 | if (coda_nc_use == 0) /* Cache is off */ |
| 476 | return; |
| 477 | |
| 478 | CODA_NC_DEBUG(CODA_NC_ZAPFILE, |
| 479 | myprintf(("Zapfile: dcp %p name %s \n" , |
| 480 | dcp, name)); ) |
| 481 | |
| 482 | if (namelen > CODA_NC_NAMELEN) { |
| 483 | coda_nc_stat.long_remove++; /* record stats */ |
| 484 | return; |
| 485 | } |
| 486 | |
| 487 | coda_nc_stat.zapFile++; |
| 488 | |
| 489 | hash = CODA_NC_HASH(name, namelen, dcp); |
| 490 | cncp = coda_nc_find(dcp, name, namelen, 0, hash); |
| 491 | |
| 492 | while (cncp) { |
| 493 | coda_nc_hash[hash].length--; /* Used for tuning */ |
| 494 | /* 1.3 */ |
| 495 | coda_nc_remove(cncp, NOT_DOWNCALL); |
| 496 | cncp = coda_nc_find(dcp, name, namelen, 0, hash); |
| 497 | } |
| 498 | } |
| 499 | |
| 500 | /* |
| 501 | * Remove all the entries for a particular user. Used when tokens expire. |
| 502 | * A user is determined by his/her effective user id (id_uid). |
| 503 | */ |
| 504 | void |
| 505 | coda_nc_purge_user(uid_t uid, enum dc_status dcstat) |
| 506 | { |
| 507 | /* |
| 508 | * I think the best approach is to go through the entire cache |
| 509 | * via HASH or whatever and zap all entries which match the |
| 510 | * input cred. Or just flush the whole cache. It might be |
| 511 | * best to go through on basis of LRU since cache will almost |
| 512 | * always be full and LRU is more straightforward. |
| 513 | */ |
| 514 | |
| 515 | struct coda_cache *cncp, *ncncp; |
| 516 | int hash; |
| 517 | |
| 518 | if (coda_nc_use == 0) /* Cache is off */ |
| 519 | return; |
| 520 | |
| 521 | CODA_NC_DEBUG(CODA_NC_PURGEUSER, |
| 522 | myprintf(("ZapDude: uid %x\n" , uid)); ) |
| 523 | coda_nc_stat.zapUsers++; |
| 524 | |
| 525 | ncncp = TAILQ_FIRST(&coda_nc_lru.head); |
| 526 | while ((cncp = ncncp) != NULL) { |
| 527 | ncncp = TAILQ_NEXT(cncp, lru); |
| 528 | |
| 529 | if ((CODA_NC_VALID(cncp)) && |
| 530 | (kauth_cred_geteuid(cncp->cred) == uid)) { |
| 531 | /* Seems really ugly, but we have to decrement the appropriate |
| 532 | hash bucket length here, so we have to find the hash bucket |
| 533 | */ |
| 534 | hash = CODA_NC_HASH(cncp->name, cncp->namelen, cncp->dcp); |
| 535 | coda_nc_hash[hash].length--; /* For performance tuning */ |
| 536 | |
| 537 | coda_nc_remove(cncp, dcstat); |
| 538 | } |
| 539 | } |
| 540 | } |
| 541 | |
| 542 | /* |
| 543 | * Flush the entire name cache. In response to a flush of the Venus cache. |
| 544 | */ |
| 545 | void |
| 546 | coda_nc_flush(enum dc_status dcstat) |
| 547 | { |
| 548 | /* One option is to deallocate the current name cache and |
| 549 | call init to start again. Or just deallocate, then rebuild. |
| 550 | Or again, we could just go through the array and zero the |
| 551 | appropriate fields. |
| 552 | */ |
| 553 | |
| 554 | /* |
| 555 | * Go through the whole lru chain and kill everything as we go. |
| 556 | * I don't use remove since that would rebuild the lru chain |
| 557 | * as it went and that seemed unneccesary. |
| 558 | */ |
| 559 | struct coda_cache *cncp; |
| 560 | int i; |
| 561 | |
| 562 | if (coda_nc_use == 0) /* Cache is off */ |
| 563 | return; |
| 564 | |
| 565 | coda_nc_stat.Flushes++; |
| 566 | |
| 567 | TAILQ_FOREACH(cncp, &coda_nc_lru.head, lru) { |
| 568 | if (CODA_NC_VALID(cncp)) { /* only zero valid nodes */ |
| 569 | LIST_REMOVE(cncp, hash); |
| 570 | memset(&cncp->hash, 0, sizeof(cncp->hash)); |
| 571 | |
| 572 | if ((dcstat == IS_DOWNCALL) |
| 573 | && (CTOV(cncp->dcp)->v_usecount == 1)) |
| 574 | { |
| 575 | cncp->dcp->c_flags |= C_PURGING; |
| 576 | } |
| 577 | vrele(CTOV(cncp->dcp)); |
| 578 | |
| 579 | if (CTOV(cncp->cp)->v_iflag & VI_TEXT) { |
| 580 | if (coda_vmflush(cncp->cp)) |
| 581 | CODADEBUG(CODA_FLUSH, |
| 582 | myprintf(("coda_nc_flush: %s busy\n" , |
| 583 | coda_f2s(&cncp->cp->c_fid))); ) |
| 584 | } |
| 585 | |
| 586 | if ((dcstat == IS_DOWNCALL) |
| 587 | && (CTOV(cncp->cp)->v_usecount == 1)) |
| 588 | { |
| 589 | cncp->cp->c_flags |= C_PURGING; |
| 590 | } |
| 591 | vrele(CTOV(cncp->cp)); |
| 592 | |
| 593 | kauth_cred_free(cncp->cred); |
| 594 | memset(DATA_PART(cncp), 0, DATA_SIZE); |
| 595 | } |
| 596 | } |
| 597 | |
| 598 | for (i = 0; i < coda_nc_hashsize; i++) |
| 599 | coda_nc_hash[i].length = 0; |
| 600 | } |
| 601 | |
| 602 | /* |
| 603 | * Debugging routines |
| 604 | */ |
| 605 | |
| 606 | /* |
| 607 | * This routine should print out all the hash chains to the console. |
| 608 | */ |
| 609 | void |
| 610 | print_coda_nc(void) |
| 611 | { |
| 612 | int hash; |
| 613 | struct coda_cache *cncp; |
| 614 | |
| 615 | for (hash = 0; hash < coda_nc_hashsize; hash++) { |
| 616 | myprintf(("\nhash %d\n" ,hash)); |
| 617 | |
| 618 | LIST_FOREACH(cncp, &coda_nc_hash[hash].head, hash) { |
| 619 | myprintf(("cp %p dcp %p cred %p name %s\n" , |
| 620 | cncp->cp, cncp->dcp, |
| 621 | cncp->cred, cncp->name)); |
| 622 | } |
| 623 | } |
| 624 | } |
| 625 | |
| 626 | void |
| 627 | coda_nc_gather_stats(void) |
| 628 | { |
| 629 | int i, xmax = 0, sum = 0, temp, zeros = 0, ave, n; |
| 630 | |
| 631 | for (i = 0; i < coda_nc_hashsize; i++) { |
| 632 | if (coda_nc_hash[i].length) { |
| 633 | sum += coda_nc_hash[i].length; |
| 634 | } else { |
| 635 | zeros++; |
| 636 | } |
| 637 | |
| 638 | if (coda_nc_hash[i].length > xmax) |
| 639 | xmax = coda_nc_hash[i].length; |
| 640 | } |
| 641 | |
| 642 | /* |
| 643 | * When computing the Arithmetic mean, only count slots which |
| 644 | * are not empty in the distribution. |
| 645 | */ |
| 646 | coda_nc_stat.Sum_bucket_len = sum; |
| 647 | coda_nc_stat.Num_zero_len = zeros; |
| 648 | coda_nc_stat.Max_bucket_len = xmax; |
| 649 | |
| 650 | if ((n = coda_nc_hashsize - zeros) > 0) |
| 651 | ave = sum / n; |
| 652 | else |
| 653 | ave = 0; |
| 654 | |
| 655 | sum = 0; |
| 656 | for (i = 0; i < coda_nc_hashsize; i++) { |
| 657 | if (coda_nc_hash[i].length) { |
| 658 | temp = coda_nc_hash[i].length - ave; |
| 659 | sum += temp * temp; |
| 660 | } |
| 661 | } |
| 662 | coda_nc_stat.Sum2_bucket_len = sum; |
| 663 | } |
| 664 | |
| 665 | /* |
| 666 | * The purpose of this routine is to allow the hash and cache sizes to be |
| 667 | * changed dynamically. This should only be used in controlled environments, |
| 668 | * it makes no effort to lock other users from accessing the cache while it |
| 669 | * is in an improper state (except by turning the cache off). |
| 670 | */ |
| 671 | int |
| 672 | coda_nc_resize(int hashsize, int heapsize, enum dc_status dcstat) |
| 673 | { |
| 674 | if ((hashsize % 2) || (heapsize % 2)) { /* Illegal hash or cache sizes */ |
| 675 | return(EINVAL); |
| 676 | } |
| 677 | |
| 678 | coda_nc_use = 0; /* Turn the cache off */ |
| 679 | |
| 680 | coda_nc_flush(dcstat); /* free any cnodes in the cache */ |
| 681 | |
| 682 | /* WARNING: free must happen *before* size is reset */ |
| 683 | CODA_FREE(coda_nc_heap,TOTAL_CACHE_SIZE); |
| 684 | CODA_FREE(coda_nc_hash,TOTAL_HASH_SIZE); |
| 685 | |
| 686 | coda_nc_hashsize = hashsize; |
| 687 | coda_nc_size = heapsize; |
| 688 | |
| 689 | coda_nc_init(); /* Set up a cache with the new size */ |
| 690 | |
| 691 | coda_nc_use = 1; /* Turn the cache back on */ |
| 692 | return(0); |
| 693 | } |
| 694 | |
| 695 | char coda_nc_name_buf[CODA_MAXNAMLEN+1]; |
| 696 | |
| 697 | void |
| 698 | coda_nc_name(struct cnode *cp) |
| 699 | { |
| 700 | struct coda_cache *cncp; |
| 701 | int i; |
| 702 | |
| 703 | if (coda_nc_use == 0) /* Cache is off */ |
| 704 | return; |
| 705 | |
| 706 | for (i = 0; i < coda_nc_hashsize; i++) { |
| 707 | |
| 708 | LIST_FOREACH(cncp, &coda_nc_hash[i].head, hash) { |
| 709 | if (cncp->cp == cp) { |
| 710 | memcpy(coda_nc_name_buf, cncp->name, cncp->namelen); |
| 711 | coda_nc_name_buf[cncp->namelen] = 0; |
| 712 | printf(" is %s (%p,%p)@%p" , |
| 713 | coda_nc_name_buf, cncp->cp, cncp->dcp, cncp); |
| 714 | } |
| 715 | |
| 716 | } |
| 717 | } |
| 718 | } |
| 719 | |