nfs_srvcache.c

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    1 /*      $NetBSD: nfs_srvcache.c,v 1.45 2009/03/15 17:20:10 cegger 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 1.45 2009/03/15 17:20:10 cegger 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(void)
  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(void)
  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(struct nfsrv_descript *nd)
  187 {
  188         struct nfsrvcache *rp;
  189 
  190         KASSERT(mutex_owned(&nfsrv_reqcache_lock));
  191 
  192 loop:
  193         LIST_FOREACH(rp, NFSRCHASH(nd->nd_retxid), rc_hash) {
  194                 if (nd->nd_retxid == rp->rc_xid &&
  195                     nd->nd_procnum == rp->rc_proc &&
  196                     netaddr_match(NETFAMILY(rp), &rp->rc_haddr, nd->nd_nam)) {
  197                         if ((rp->rc_gflags & RC_G_LOCKED) != 0) {
  198                                 cv_wait(&rp->rc_cv, &nfsrv_reqcache_lock);
  199                                 goto loop;
  200                         }
  201                         rp->rc_gflags |= RC_G_LOCKED;
  202                         break;
  203                 }
  204         }
  205 
  206         return rp;
  207 }
  208 
  209 /*
  210  * Unlock a cache
  211  */
  212 static void
  213 nfsrv_unlockcache(struct nfsrvcache *rp)
  214 {
  215 
  216         KASSERT(mutex_owned(&nfsrv_reqcache_lock));
  217 
  218         KASSERT((rp->rc_gflags & RC_G_LOCKED) != 0);
  219         rp->rc_gflags &= ~RC_G_LOCKED;
  220         cv_broadcast(&rp->rc_cv);
  221 }
  222 
  223 /*
  224  * Look for the request in the cache
  225  * If found then
  226  *    return action and optionally reply
  227  * else
  228  *    insert it in the cache
  229  *
  230  * The rules are as follows:
  231  * - if in progress, return DROP request
  232  * - if completed within DELAY of the current time, return DROP it
  233  * - if completed a longer time ago return REPLY if the reply was cached or
  234  *   return DOIT
  235  * Update/add new request at end of lru list
  236  */
  237 int
  238 nfsrv_getcache(struct nfsrv_descript *nd, struct nfssvc_sock *slp, struct mbuf **repp)
  239 {
  240         struct nfsrvcache *rp, *rpdup;
  241         struct mbuf *mb;
  242         struct sockaddr_in *saddr;
  243         char *bpos;
  244         int ret;
  245 
  246         mutex_enter(&nfsrv_reqcache_lock);
  247         rp = nfsrv_lookupcache(nd);
  248         if (rp) {
  249                 mutex_exit(&nfsrv_reqcache_lock);
  250 found:
  251                 /* If not at end of LRU chain, move it there */
  252                 if (TAILQ_NEXT(rp, rc_lru)) { /* racy but ok */
  253                         mutex_enter(&nfsrv_reqcache_lock);
  254                         TAILQ_REMOVE(&nfsrvlruhead, rp, rc_lru);
  255                         TAILQ_INSERT_TAIL(&nfsrvlruhead, rp, rc_lru);
  256                         mutex_exit(&nfsrv_reqcache_lock);
  257                 }
  258                 if (rp->rc_state == RC_UNUSED)
  259                         panic("nfsrv cache");
  260                 if (rp->rc_state == RC_INPROG) {
  261                         nfsstats.srvcache_inproghits++;
  262                         ret = RC_DROPIT;
  263                 } else if (rp->rc_flags & RC_REPSTATUS) {
  264                         nfsstats.srvcache_nonidemdonehits++;
  265                         nfs_rephead(0, nd, slp, rp->rc_status,
  266                            0, (u_quad_t *)0, repp, &mb, &bpos);
  267                         ret = RC_REPLY;
  268                 } else if (rp->rc_flags & RC_REPMBUF) {
  269                         nfsstats.srvcache_nonidemdonehits++;
  270                         *repp = m_copym(rp->rc_reply, 0, M_COPYALL,
  271                                         M_WAIT);
  272                         ret = RC_REPLY;
  273                 } else {
  274                         nfsstats.srvcache_idemdonehits++;
  275                         rp->rc_state = RC_INPROG;
  276                         ret = RC_DOIT;
  277                 }
  278                 mutex_enter(&nfsrv_reqcache_lock);
  279                 nfsrv_unlockcache(rp);
  280                 mutex_exit(&nfsrv_reqcache_lock);
  281                 return ret;
  282         }
  283         nfsstats.srvcache_misses++;
  284         if (numnfsrvcache < desirednfsrvcache) {
  285                 numnfsrvcache++;
  286                 mutex_exit(&nfsrv_reqcache_lock);
  287                 rp = pool_get(&nfs_reqcache_pool, PR_WAITOK);
  288                 memset(rp, 0, sizeof *rp);
  289                 cv_init(&rp->rc_cv, "nfsdrc");
  290                 rp->rc_gflags = RC_G_LOCKED;
  291         } else {
  292                 rp = TAILQ_FIRST(&nfsrvlruhead);
  293                 while ((rp->rc_gflags & RC_G_LOCKED) != 0) {
  294                         cv_wait(&rp->rc_cv, &nfsrv_reqcache_lock);
  295                         rp = TAILQ_FIRST(&nfsrvlruhead);
  296                 }
  297                 rp->rc_gflags |= RC_G_LOCKED;
  298                 LIST_REMOVE(rp, rc_hash);
  299                 TAILQ_REMOVE(&nfsrvlruhead, rp, rc_lru);
  300                 mutex_exit(&nfsrv_reqcache_lock);
  301                 cleanentry(rp);
  302                 rp->rc_flags = 0;
  303         }
  304         rp->rc_state = RC_INPROG;
  305         rp->rc_xid = nd->nd_retxid;
  306         saddr = mtod(nd->nd_nam, struct sockaddr_in *);
  307         switch (saddr->sin_family) {
  308         case AF_INET:
  309                 rp->rc_flags |= RC_INETADDR;
  310                 rp->rc_inetaddr = saddr->sin_addr.s_addr;
  311                 break;
  312         default:
  313                 rp->rc_flags |= RC_NAM;
  314                 rp->rc_nam = m_copym(nd->nd_nam, 0, M_COPYALL, M_WAIT);
  315                 m_claimm(rp->rc_nam, &nfsd_cache_mowner);
  316                 break;
  317         };
  318         rp->rc_proc = nd->nd_procnum;
  319         mutex_enter(&nfsrv_reqcache_lock);
  320         rpdup = nfsrv_lookupcache(nd);
  321         if (rpdup != NULL) {
  322                 /*
  323                  * other thread made duplicate cache entry.
  324                  */
  325                 KASSERT(numnfsrvcache > 0);
  326                 numnfsrvcache--;
  327                 mutex_exit(&nfsrv_reqcache_lock);
  328                 cleanentry(rp);
  329                 cv_destroy(&rp->rc_cv);
  330                 pool_put(&nfs_reqcache_pool, rp);
  331                 rp = rpdup;
  332                 goto found;
  333         }
  334         TAILQ_INSERT_TAIL(&nfsrvlruhead, rp, rc_lru);
  335         LIST_INSERT_HEAD(NFSRCHASH(nd->nd_retxid), rp, rc_hash);
  336         nfsrv_unlockcache(rp);
  337         mutex_exit(&nfsrv_reqcache_lock);
  338         return RC_DOIT;
  339 }
  340 
  341 /*
  342  * Update a request cache entry after the rpc has been done
  343  */
  344 void
  345 nfsrv_updatecache(struct nfsrv_descript *nd, int repvalid, struct mbuf *repmbuf)
  346 {
  347         struct nfsrvcache *rp;
  348 
  349         mutex_enter(&nfsrv_reqcache_lock);
  350         rp = nfsrv_lookupcache(nd);
  351         mutex_exit(&nfsrv_reqcache_lock);
  352         if (rp) {
  353                 cleanentry(rp);
  354                 rp->rc_state = RC_DONE;
  355                 /*
  356                  * If we have a valid reply update status and save
  357                  * the reply for non-idempotent rpc's.
  358                  */
  359                 if (repvalid && nonidempotent[nd->nd_procnum]) {
  360                         if ((nd->nd_flag & ND_NFSV3) == 0 &&
  361                           nfsv2_repstat[nfsv2_procid[nd->nd_procnum]]) {
  362                                 rp->rc_status = nd->nd_repstat;
  363                                 rp->rc_flags |= RC_REPSTATUS;
  364                         } else {
  365                                 rp->rc_reply = m_copym(repmbuf,
  366                                         0, M_COPYALL, M_WAIT);
  367                                 m_claimm(rp->rc_reply, &nfsd_cache_mowner);
  368                                 rp->rc_flags |= RC_REPMBUF;
  369                         }
  370                 }
  371                 mutex_enter(&nfsrv_reqcache_lock);
  372                 nfsrv_unlockcache(rp);
  373                 mutex_exit(&nfsrv_reqcache_lock);
  374         }
  375 }
  376 
  377 /*
  378  * Clean out the cache. Called when the last nfsd terminates.
  379  */
  380 void
  381 nfsrv_cleancache(void)
  382 {
  383         struct nfsrvcache *rp;
  384 
  385         mutex_enter(&nfsrv_reqcache_lock);
  386         while ((rp = TAILQ_FIRST(&nfsrvlruhead)) != NULL) {
  387                 KASSERT((rp->rc_gflags & RC_G_LOCKED) == 0);
  388                 LIST_REMOVE(rp, rc_hash);
  389                 TAILQ_REMOVE(&nfsrvlruhead, rp, rc_lru);
  390                 KASSERT(numnfsrvcache > 0);
  391                 numnfsrvcache--;
  392                 mutex_exit(&nfsrv_reqcache_lock);
  393                 cleanentry(rp);
  394                 cv_destroy(&rp->rc_cv);
  395                 pool_put(&nfs_reqcache_pool, rp);
  396                 mutex_enter(&nfsrv_reqcache_lock);
  397         }
  398         KASSERT(numnfsrvcache == 0);
  399         mutex_exit(&nfsrv_reqcache_lock);
  400 }
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FreeBSD/Linux Kernel Cross Reference sys/nfs/nfs_srvcache.c

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