1 /* $NetBSD: nfs_srvcache.c,v 1.43 2008/11/19 18:36:09 ad Exp $ */ 2 3 /* 4 * Copyright (c) 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Rick Macklem at The University of Guelph. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)nfs_srvcache.c 8.3 (Berkeley) 3/30/95 35 */ 36 37 /* 38 * Reference: Chet Juszczak, "Improving the Performance and Correctness 39 * of an NFS Server", in Proc. Winter 1989 USENIX Conference, 40 * pages 53-63. San Diego, February 1989. 41 */ 42 43 #include <sys/cdefs.h> 44 __KERNEL_RCSID(0, "$NetBSD: nfs_srvcache.c,v 1.43 2008/11/19 18:36:09 ad Exp $"); 45 46 #include <sys/param.h> 47 #include <sys/vnode.h> 48 #include <sys/condvar.h> 49 #include <sys/mount.h> 50 #include <sys/kernel.h> 51 #include <sys/systm.h> 52 #include <sys/lock.h> 53 #include <sys/proc.h> 54 #include <sys/pool.h> 55 #include <sys/mbuf.h> 56 #include <sys/mutex.h> 57 #include <sys/socket.h> 58 #include <sys/socketvar.h> 59 60 #include <netinet/in.h> 61 #include <nfs/nfsm_subs.h> 62 #include <nfs/rpcv2.h> 63 #include <nfs/nfsproto.h> 64 #include <nfs/nfs.h> 65 #include <nfs/nfsrvcache.h> 66 #include <nfs/nfs_var.h> 67 68 extern struct nfsstats nfsstats; 69 extern const int nfsv2_procid[NFS_NPROCS]; 70 long numnfsrvcache, desirednfsrvcache = NFSRVCACHESIZ; 71 struct pool nfs_reqcache_pool; 72 73 #define NFSRCHASH(xid) \ 74 (&nfsrvhashtbl[((xid) + ((xid) >> 24)) & nfsrvhash]) 75 LIST_HEAD(nfsrvhash, nfsrvcache) *nfsrvhashtbl; 76 TAILQ_HEAD(nfsrvlru, nfsrvcache) nfsrvlruhead; 77 kmutex_t nfsrv_reqcache_lock; 78 u_long nfsrvhash; 79 80 #if defined(MBUFTRACE) 81 static struct mowner nfsd_cache_mowner = MOWNER_INIT("nfsd", "cache"); 82 #endif /* defined(MBUFTRACE) */ 83 84 #define NETFAMILY(rp) \ 85 (((rp)->rc_flags & RC_INETADDR) ? AF_INET : -1) 86 87 static struct nfsrvcache *nfsrv_lookupcache(struct nfsrv_descript *nd); 88 static void nfsrv_unlockcache(struct nfsrvcache *rp); 89 90 /* 91 * Static array that defines which nfs rpc's are nonidempotent 92 */ 93 const int nonidempotent[NFS_NPROCS] = { 94 false, /* NULL */ 95 false, /* GETATTR */ 96 true, /* SETATTR */ 97 false, /* LOOKUP */ 98 false, /* ACCESS */ 99 false, /* READLINK */ 100 false, /* READ */ 101 true, /* WRITE */ 102 true, /* CREATE */ 103 true, /* MKDIR */ 104 true, /* SYMLINK */ 105 true, /* MKNOD */ 106 true, /* REMOVE */ 107 true, /* RMDIR */ 108 true, /* RENAME */ 109 true, /* LINK */ 110 false, /* READDIR */ 111 false, /* READDIRPLUS */ 112 false, /* FSSTAT */ 113 false, /* FSINFO */ 114 false, /* PATHCONF */ 115 false, /* COMMIT */ 116 false, /* NOOP */ 117 }; 118 119 /* True iff the rpc reply is an nfs status ONLY! */ 120 static const int nfsv2_repstat[NFS_NPROCS] = { 121 false, /* NULL */ 122 false, /* GETATTR */ 123 false, /* SETATTR */ 124 false, /* NOOP */ 125 false, /* LOOKUP */ 126 false, /* READLINK */ 127 false, /* READ */ 128 false, /* Obsolete WRITECACHE */ 129 false, /* WRITE */ 130 false, /* CREATE */ 131 true, /* REMOVE */ 132 true, /* RENAME */ 133 true, /* LINK */ 134 true, /* SYMLINK */ 135 false, /* MKDIR */ 136 true, /* RMDIR */ 137 false, /* READDIR */ 138 false, /* STATFS */ 139 }; 140 141 static void 142 cleanentry(struct nfsrvcache *rp) 143 { 144 145 if ((rp->rc_flags & RC_REPMBUF) != 0) { 146 m_freem(rp->rc_reply); 147 } 148 if ((rp->rc_flags & RC_NAM) != 0) { 149 m_free(rp->rc_nam); 150 } 151 rp->rc_flags &= ~(RC_REPSTATUS|RC_REPMBUF); 152 } 153 154 /* 155 * Initialize the server request cache list 156 */ 157 void 158 nfsrv_initcache() 159 { 160 161 mutex_init(&nfsrv_reqcache_lock, MUTEX_DEFAULT, IPL_NONE); 162 nfsrvhashtbl = hashinit(desirednfsrvcache, HASH_LIST, true, 163 &nfsrvhash); 164 TAILQ_INIT(&nfsrvlruhead); 165 pool_init(&nfs_reqcache_pool, sizeof(struct nfsrvcache), 0, 0, 0, 166 "nfsreqcachepl", &pool_allocator_nointr, IPL_NONE); 167 MOWNER_ATTACH(&nfsd_cache_mowner); 168 } 169 170 void 171 nfsrv_finicache() 172 { 173 174 nfsrv_cleancache(); 175 KASSERT(TAILQ_EMPTY(&nfsrvlruhead)); 176 pool_destroy(&nfs_reqcache_pool); 177 hashdone(nfsrvhashtbl, HASH_LIST, nfsrvhash); 178 MOWNER_DETACH(&nfsd_cache_mowner); 179 mutex_destroy(&nfsrv_reqcache_lock); 180 } 181 182 /* 183 * Lookup a cache and lock it 184 */ 185 static struct nfsrvcache * 186 nfsrv_lookupcache(nd) 187 struct nfsrv_descript *nd; 188 { 189 struct nfsrvcache *rp; 190 191 KASSERT(mutex_owned(&nfsrv_reqcache_lock)); 192 193 loop: 194 LIST_FOREACH(rp, NFSRCHASH(nd->nd_retxid), rc_hash) { 195 if (nd->nd_retxid == rp->rc_xid && 196 nd->nd_procnum == rp->rc_proc && 197 netaddr_match(NETFAMILY(rp), &rp->rc_haddr, nd->nd_nam)) { 198 if ((rp->rc_gflags & RC_G_LOCKED) != 0) { 199 cv_wait(&rp->rc_cv, &nfsrv_reqcache_lock); 200 goto loop; 201 } 202 rp->rc_gflags |= RC_G_LOCKED; 203 break; 204 } 205 } 206 207 return rp; 208 } 209 210 /* 211 * Unlock a cache 212 */ 213 static void 214 nfsrv_unlockcache(rp) 215 struct nfsrvcache *rp; 216 { 217 218 KASSERT(mutex_owned(&nfsrv_reqcache_lock)); 219 220 KASSERT((rp->rc_gflags & RC_G_LOCKED) != 0); 221 rp->rc_gflags &= ~RC_G_LOCKED; 222 cv_broadcast(&rp->rc_cv); 223 } 224 225 /* 226 * Look for the request in the cache 227 * If found then 228 * return action and optionally reply 229 * else 230 * insert it in the cache 231 * 232 * The rules are as follows: 233 * - if in progress, return DROP request 234 * - if completed within DELAY of the current time, return DROP it 235 * - if completed a longer time ago return REPLY if the reply was cached or 236 * return DOIT 237 * Update/add new request at end of lru list 238 */ 239 int 240 nfsrv_getcache(nd, slp, repp) 241 struct nfsrv_descript *nd; 242 struct nfssvc_sock *slp; 243 struct mbuf **repp; 244 { 245 struct nfsrvcache *rp, *rpdup; 246 struct mbuf *mb; 247 struct sockaddr_in *saddr; 248 char *bpos; 249 int ret; 250 251 mutex_enter(&nfsrv_reqcache_lock); 252 rp = nfsrv_lookupcache(nd); 253 if (rp) { 254 mutex_exit(&nfsrv_reqcache_lock); 255 found: 256 /* If not at end of LRU chain, move it there */ 257 if (TAILQ_NEXT(rp, rc_lru)) { /* racy but ok */ 258 mutex_enter(&nfsrv_reqcache_lock); 259 TAILQ_REMOVE(&nfsrvlruhead, rp, rc_lru); 260 TAILQ_INSERT_TAIL(&nfsrvlruhead, rp, rc_lru); 261 mutex_exit(&nfsrv_reqcache_lock); 262 } 263 if (rp->rc_state == RC_UNUSED) 264 panic("nfsrv cache"); 265 if (rp->rc_state == RC_INPROG) { 266 nfsstats.srvcache_inproghits++; 267 ret = RC_DROPIT; 268 } else if (rp->rc_flags & RC_REPSTATUS) { 269 nfsstats.srvcache_nonidemdonehits++; 270 nfs_rephead(0, nd, slp, rp->rc_status, 271 0, (u_quad_t *)0, repp, &mb, &bpos); 272 ret = RC_REPLY; 273 } else if (rp->rc_flags & RC_REPMBUF) { 274 nfsstats.srvcache_nonidemdonehits++; 275 *repp = m_copym(rp->rc_reply, 0, M_COPYALL, 276 M_WAIT); 277 ret = RC_REPLY; 278 } else { 279 nfsstats.srvcache_idemdonehits++; 280 rp->rc_state = RC_INPROG; 281 ret = RC_DOIT; 282 } 283 mutex_enter(&nfsrv_reqcache_lock); 284 nfsrv_unlockcache(rp); 285 mutex_exit(&nfsrv_reqcache_lock); 286 return ret; 287 } 288 nfsstats.srvcache_misses++; 289 if (numnfsrvcache < desirednfsrvcache) { 290 numnfsrvcache++; 291 mutex_exit(&nfsrv_reqcache_lock); 292 rp = pool_get(&nfs_reqcache_pool, PR_WAITOK); 293 memset(rp, 0, sizeof *rp); 294 cv_init(&rp->rc_cv, "nfsdrc"); 295 rp->rc_gflags = RC_G_LOCKED; 296 } else { 297 rp = TAILQ_FIRST(&nfsrvlruhead); 298 while ((rp->rc_gflags & RC_G_LOCKED) != 0) { 299 cv_wait(&rp->rc_cv, &nfsrv_reqcache_lock); 300 rp = TAILQ_FIRST(&nfsrvlruhead); 301 } 302 rp->rc_gflags |= RC_G_LOCKED; 303 LIST_REMOVE(rp, rc_hash); 304 TAILQ_REMOVE(&nfsrvlruhead, rp, rc_lru); 305 mutex_exit(&nfsrv_reqcache_lock); 306 cleanentry(rp); 307 rp->rc_flags = 0; 308 } 309 rp->rc_state = RC_INPROG; 310 rp->rc_xid = nd->nd_retxid; 311 saddr = mtod(nd->nd_nam, struct sockaddr_in *); 312 switch (saddr->sin_family) { 313 case AF_INET: 314 rp->rc_flags |= RC_INETADDR; 315 rp->rc_inetaddr = saddr->sin_addr.s_addr; 316 break; 317 default: 318 rp->rc_flags |= RC_NAM; 319 rp->rc_nam = m_copym(nd->nd_nam, 0, M_COPYALL, M_WAIT); 320 m_claimm(rp->rc_nam, &nfsd_cache_mowner); 321 break; 322 }; 323 rp->rc_proc = nd->nd_procnum; 324 mutex_enter(&nfsrv_reqcache_lock); 325 rpdup = nfsrv_lookupcache(nd); 326 if (rpdup != NULL) { 327 /* 328 * other thread made duplicate cache entry. 329 */ 330 KASSERT(numnfsrvcache > 0); 331 numnfsrvcache--; 332 mutex_exit(&nfsrv_reqcache_lock); 333 cleanentry(rp); 334 cv_destroy(&rp->rc_cv); 335 pool_put(&nfs_reqcache_pool, rp); 336 rp = rpdup; 337 goto found; 338 } 339 TAILQ_INSERT_TAIL(&nfsrvlruhead, rp, rc_lru); 340 LIST_INSERT_HEAD(NFSRCHASH(nd->nd_retxid), rp, rc_hash); 341 nfsrv_unlockcache(rp); 342 mutex_exit(&nfsrv_reqcache_lock); 343 return RC_DOIT; 344 } 345 346 /* 347 * Update a request cache entry after the rpc has been done 348 */ 349 void 350 nfsrv_updatecache(nd, repvalid, repmbuf) 351 struct nfsrv_descript *nd; 352 int repvalid; 353 struct mbuf *repmbuf; 354 { 355 struct nfsrvcache *rp; 356 357 mutex_enter(&nfsrv_reqcache_lock); 358 rp = nfsrv_lookupcache(nd); 359 mutex_exit(&nfsrv_reqcache_lock); 360 if (rp) { 361 cleanentry(rp); 362 rp->rc_state = RC_DONE; 363 /* 364 * If we have a valid reply update status and save 365 * the reply for non-idempotent rpc's. 366 */ 367 if (repvalid && nonidempotent[nd->nd_procnum]) { 368 if ((nd->nd_flag & ND_NFSV3) == 0 && 369 nfsv2_repstat[nfsv2_procid[nd->nd_procnum]]) { 370 rp->rc_status = nd->nd_repstat; 371 rp->rc_flags |= RC_REPSTATUS; 372 } else { 373 rp->rc_reply = m_copym(repmbuf, 374 0, M_COPYALL, M_WAIT); 375 m_claimm(rp->rc_reply, &nfsd_cache_mowner); 376 rp->rc_flags |= RC_REPMBUF; 377 } 378 } 379 mutex_enter(&nfsrv_reqcache_lock); 380 nfsrv_unlockcache(rp); 381 mutex_exit(&nfsrv_reqcache_lock); 382 } 383 } 384 385 /* 386 * Clean out the cache. Called when the last nfsd terminates. 387 */ 388 void 389 nfsrv_cleancache() 390 { 391 struct nfsrvcache *rp; 392 393 mutex_enter(&nfsrv_reqcache_lock); 394 while ((rp = TAILQ_FIRST(&nfsrvlruhead)) != NULL) { 395 KASSERT((rp->rc_gflags & RC_G_LOCKED) == 0); 396 LIST_REMOVE(rp, rc_hash); 397 TAILQ_REMOVE(&nfsrvlruhead, rp, rc_lru); 398 KASSERT(numnfsrvcache > 0); 399 numnfsrvcache--; 400 mutex_exit(&nfsrv_reqcache_lock); 401 cleanentry(rp); 402 cv_destroy(&rp->rc_cv); 403 pool_put(&nfs_reqcache_pool, rp); 404 mutex_enter(&nfsrv_reqcache_lock); 405 } 406 KASSERT(numnfsrvcache == 0); 407 mutex_exit(&nfsrv_reqcache_lock); 408 } 409