The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/nfs/nfs_srvcache.c

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    1 /*      $NetBSD: nfs_srvcache.c,v 1.32.24.2 2007/06/05 20:40:13 bouyer 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 1.32.24.2 2007/06/05 20:40:13 bouyer Exp $");
   45 
   46 #include "opt_iso.h"
   47 
   48 #include <sys/param.h>
   49 #include <sys/vnode.h>
   50 #include <sys/mount.h>
   51 #include <sys/kernel.h>
   52 #include <sys/systm.h>
   53 #include <sys/lock.h>
   54 #include <sys/proc.h>
   55 #include <sys/pool.h>
   56 #include <sys/mbuf.h>
   57 #include <sys/malloc.h>
   58 #include <sys/socket.h>
   59 #include <sys/socketvar.h>
   60 
   61 #include <netinet/in.h>
   62 #ifdef ISO
   63 #include <netiso/iso.h>
   64 #endif
   65 #include <nfs/nfsm_subs.h>
   66 #include <nfs/rpcv2.h>
   67 #include <nfs/nfsproto.h>
   68 #include <nfs/nfs.h>
   69 #include <nfs/nfsrvcache.h>
   70 #include <nfs/nqnfs.h>
   71 #include <nfs/nfs_var.h>
   72 
   73 extern struct nfsstats nfsstats;
   74 extern const int nfsv2_procid[NFS_NPROCS];
   75 long numnfsrvcache, desirednfsrvcache = NFSRVCACHESIZ;
   76 struct pool nfs_reqcache_pool;
   77 
   78 #define NFSRCHASH(xid) \
   79         (&nfsrvhashtbl[((xid) + ((xid) >> 24)) & nfsrvhash])
   80 LIST_HEAD(nfsrvhash, nfsrvcache) *nfsrvhashtbl;
   81 TAILQ_HEAD(nfsrvlru, nfsrvcache) nfsrvlruhead;
   82 struct simplelock nfsrv_reqcache_lock = SIMPLELOCK_INITIALIZER;
   83 u_long nfsrvhash;
   84 
   85 #define NETFAMILY(rp) \
   86                 (((rp)->rc_flag & RC_INETADDR) ? AF_INET : AF_ISO)
   87 
   88 static struct nfsrvcache *nfsrv_lookupcache(struct nfsrv_descript *nd);
   89 static void nfsrv_unlockcache(struct nfsrvcache *rp);
   90 
   91 /*
   92  * Static array that defines which nfs rpc's are nonidempotent
   93  */
   94 const int nonidempotent[NFS_NPROCS] = {
   95         FALSE,  /* NULL */
   96         FALSE,  /* GETATTR */
   97         TRUE,   /* SETATTR */
   98         FALSE,  /* LOOKUP */
   99         FALSE,  /* ACCESS */
  100         FALSE,  /* READLINK */
  101         FALSE,  /* READ */
  102         TRUE,   /* WRITE */
  103         TRUE,   /* CREATE */
  104         TRUE,   /* MKDIR */
  105         TRUE,   /* SYMLINK */
  106         TRUE,   /* MKNOD */
  107         TRUE,   /* REMOVE */
  108         TRUE,   /* RMDIR */
  109         TRUE,   /* RENAME */
  110         TRUE,   /* LINK */
  111         FALSE,  /* READDIR */
  112         FALSE,  /* READDIRPLUS */
  113         FALSE,  /* FSSTAT */
  114         FALSE,  /* FSINFO */
  115         FALSE,  /* PATHCONF */
  116         FALSE,  /* COMMIT */
  117         FALSE,  /* GETLEASE */
  118         FALSE,  /* VACATED */
  119         FALSE,  /* EVICTED */
  120         FALSE,  /* NOOP */
  121 };
  122 
  123 /* True iff the rpc reply is an nfs status ONLY! */
  124 static const int nfsv2_repstat[NFS_NPROCS] = {
  125         FALSE,  /* NULL */
  126         FALSE,  /* GETATTR */
  127         FALSE,  /* SETATTR */
  128         FALSE,  /* NOOP */
  129         FALSE,  /* LOOKUP */
  130         FALSE,  /* READLINK */
  131         FALSE,  /* READ */
  132         FALSE,  /* Obsolete WRITECACHE */
  133         FALSE,  /* WRITE */
  134         FALSE,  /* CREATE */
  135         TRUE,   /* REMOVE */
  136         TRUE,   /* RENAME */
  137         TRUE,   /* LINK */
  138         TRUE,   /* SYMLINK */
  139         FALSE,  /* MKDIR */
  140         TRUE,   /* RMDIR */
  141         FALSE,  /* READDIR */
  142         FALSE,  /* STATFS */
  143 };
  144 
  145 static void
  146 cleanentry(struct nfsrvcache *rp)
  147 {
  148 
  149         if ((rp->rc_flag & RC_REPMBUF) != 0) {
  150                 m_freem(rp->rc_reply);
  151         }
  152         if ((rp->rc_flag & RC_NAM) != 0) {
  153                 m_free(rp->rc_nam);
  154         }
  155         rp->rc_flag &= ~(RC_REPSTATUS|RC_REPMBUF);
  156 }
  157 
  158 /*
  159  * Initialize the server request cache list
  160  */
  161 void
  162 nfsrv_initcache()
  163 {
  164 
  165         nfsrvhashtbl = hashinit(desirednfsrvcache, HASH_LIST, M_NFSD,
  166             M_WAITOK, &nfsrvhash);
  167         TAILQ_INIT(&nfsrvlruhead);
  168         pool_init(&nfs_reqcache_pool, sizeof(struct nfsrvcache), 0, 0, 0,
  169             "nfsreqcachepl", &pool_allocator_nointr);
  170 }
  171 
  172 /*
  173  * Lookup a cache and lock it
  174  */
  175 static struct nfsrvcache *
  176 nfsrv_lookupcache(nd)
  177         struct nfsrv_descript *nd;
  178 {
  179         struct nfsrvcache *rp;
  180 
  181         LOCK_ASSERT(simple_lock_held(&nfsrv_reqcache_lock));
  182 
  183 loop:
  184         LIST_FOREACH(rp, NFSRCHASH(nd->nd_retxid), rc_hash) {
  185                 if (nd->nd_retxid == rp->rc_xid &&
  186                     nd->nd_procnum == rp->rc_proc &&
  187                     netaddr_match(NETFAMILY(rp), &rp->rc_haddr, nd->nd_nam)) {
  188                         if ((rp->rc_flag & RC_LOCKED) != 0) {
  189                                 rp->rc_flag |= RC_WANTED;
  190                                 (void) ltsleep(rp, PZERO - 1, "nfsrc", 0,
  191                                     &nfsrv_reqcache_lock);
  192                                 goto loop;
  193                         }
  194                         rp->rc_flag |= RC_LOCKED;
  195                         break;
  196                 }
  197         }
  198 
  199         return rp;
  200 }
  201 
  202 /*
  203  * Unlock a cache
  204  */
  205 static void
  206 nfsrv_unlockcache(rp)
  207         struct nfsrvcache *rp;
  208 {
  209 
  210         LOCK_ASSERT(simple_lock_held(&nfsrv_reqcache_lock));
  211 
  212         rp->rc_flag &= ~RC_LOCKED;
  213         if (rp->rc_flag & RC_WANTED) {
  214                 rp->rc_flag &= ~RC_WANTED;
  215                 wakeup(rp);
  216         }
  217 }
  218 
  219 /*
  220  * Look for the request in the cache
  221  * If found then
  222  *    return action and optionally reply
  223  * else
  224  *    insert it in the cache
  225  *
  226  * The rules are as follows:
  227  * - if in progress, return DROP request
  228  * - if completed within DELAY of the current time, return DROP it
  229  * - if completed a longer time ago return REPLY if the reply was cached or
  230  *   return DOIT
  231  * Update/add new request at end of lru list
  232  */
  233 int
  234 nfsrv_getcache(nd, slp, repp)
  235         struct nfsrv_descript *nd;
  236         struct nfssvc_sock *slp;
  237         struct mbuf **repp;
  238 {
  239         struct nfsrvcache *rp, *rpdup;
  240         struct mbuf *mb;
  241         struct sockaddr_in *saddr;
  242         caddr_t bpos;
  243         int ret;
  244 
  245         simple_lock(&nfsrv_reqcache_lock);
  246         rp = nfsrv_lookupcache(nd);
  247         if (rp) {
  248                 simple_unlock(&nfsrv_reqcache_lock);
  249 found:
  250                 /* If not at end of LRU chain, move it there */
  251                 if (TAILQ_NEXT(rp, rc_lru)) { /* racy but ok */
  252                         simple_lock(&nfsrv_reqcache_lock);
  253                         TAILQ_REMOVE(&nfsrvlruhead, rp, rc_lru);
  254                         TAILQ_INSERT_TAIL(&nfsrvlruhead, rp, rc_lru);
  255                         simple_unlock(&nfsrv_reqcache_lock);
  256                 }
  257                 if (rp->rc_state == RC_UNUSED)
  258                         panic("nfsrv cache");
  259                 if (rp->rc_state == RC_INPROG) {
  260                         nfsstats.srvcache_inproghits++;
  261                         ret = RC_DROPIT;
  262                 } else if (rp->rc_flag & RC_REPSTATUS) {
  263                         nfsstats.srvcache_nonidemdonehits++;
  264                         nfs_rephead(0, nd, slp, rp->rc_status,
  265                            0, (u_quad_t *)0, repp, &mb, &bpos);
  266                         ret = RC_REPLY;
  267                 } else if (rp->rc_flag & RC_REPMBUF) {
  268                         nfsstats.srvcache_nonidemdonehits++;
  269                         *repp = m_copym(rp->rc_reply, 0, M_COPYALL,
  270                                         M_WAIT);
  271                         ret = RC_REPLY;
  272                 } else {
  273                         nfsstats.srvcache_idemdonehits++;
  274                         rp->rc_state = RC_INPROG;
  275                         ret = RC_DOIT;
  276                 }
  277                 simple_lock(&nfsrv_reqcache_lock);
  278                 nfsrv_unlockcache(rp);
  279                 simple_unlock(&nfsrv_reqcache_lock);
  280                 return ret;
  281         }
  282         nfsstats.srvcache_misses++;
  283         if (numnfsrvcache < desirednfsrvcache) {
  284                 numnfsrvcache++;
  285                 simple_unlock(&nfsrv_reqcache_lock);
  286                 rp = pool_get(&nfs_reqcache_pool, PR_WAITOK);
  287                 memset(rp, 0, sizeof *rp);
  288                 rp->rc_flag = RC_LOCKED;
  289         } else {
  290                 rp = TAILQ_FIRST(&nfsrvlruhead);
  291                 while ((rp->rc_flag & RC_LOCKED) != 0) {
  292                         rp->rc_flag |= RC_WANTED;
  293                         (void) ltsleep(rp, PZERO-1, "nfsrc", 0,
  294                             &nfsrv_reqcache_lock);
  295                         rp = TAILQ_FIRST(&nfsrvlruhead);
  296                 }
  297                 rp->rc_flag |= RC_LOCKED;
  298                 LIST_REMOVE(rp, rc_hash);
  299                 TAILQ_REMOVE(&nfsrvlruhead, rp, rc_lru);
  300                 simple_unlock(&nfsrv_reqcache_lock);
  301                 cleanentry(rp);
  302                 rp->rc_flag &= (RC_LOCKED | RC_WANTED);
  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_flag |= RC_INETADDR;
  310                 rp->rc_inetaddr = saddr->sin_addr.s_addr;
  311                 break;
  312         case AF_ISO:
  313         default:
  314                 rp->rc_flag |= RC_NAM;
  315                 rp->rc_nam = m_copym(nd->nd_nam, 0, M_COPYALL, M_WAIT);
  316                 break;
  317         };
  318         rp->rc_proc = nd->nd_procnum;
  319         simple_lock(&nfsrv_reqcache_lock);
  320         rpdup = nfsrv_lookupcache(nd);
  321         if (rpdup != NULL) {
  322                 /*
  323                  * other thread made duplicate cache entry.
  324                  */
  325                 simple_unlock(&nfsrv_reqcache_lock);
  326                 pool_put(&nfs_reqcache_pool, rp);
  327                 rp = rpdup;
  328                 goto found;
  329         }
  330         TAILQ_INSERT_TAIL(&nfsrvlruhead, rp, rc_lru);
  331         LIST_INSERT_HEAD(NFSRCHASH(nd->nd_retxid), rp, rc_hash);
  332         nfsrv_unlockcache(rp);
  333         simple_unlock(&nfsrv_reqcache_lock);
  334         return RC_DOIT;
  335 }
  336 
  337 /*
  338  * Update a request cache entry after the rpc has been done
  339  */
  340 void
  341 nfsrv_updatecache(nd, repvalid, repmbuf)
  342         struct nfsrv_descript *nd;
  343         int repvalid;
  344         struct mbuf *repmbuf;
  345 {
  346         struct nfsrvcache *rp;
  347 
  348         simple_lock(&nfsrv_reqcache_lock);
  349         rp = nfsrv_lookupcache(nd);
  350         simple_unlock(&nfsrv_reqcache_lock);
  351         if (rp) {
  352                 cleanentry(rp);
  353                 rp->rc_state = RC_DONE;
  354                 /*
  355                  * If we have a valid reply update status and save
  356                  * the reply for non-idempotent rpc's.
  357                  */
  358                 if (repvalid && nonidempotent[nd->nd_procnum]) {
  359                         if ((nd->nd_flag & ND_NFSV3) == 0 &&
  360                           nfsv2_repstat[nfsv2_procid[nd->nd_procnum]]) {
  361                                 rp->rc_status = nd->nd_repstat;
  362                                 rp->rc_flag |= RC_REPSTATUS;
  363                         } else {
  364                                 rp->rc_reply = m_copym(repmbuf,
  365                                         0, M_COPYALL, M_WAIT);
  366                                 rp->rc_flag |= RC_REPMBUF;
  367                         }
  368                 }
  369                 simple_lock(&nfsrv_reqcache_lock);
  370                 nfsrv_unlockcache(rp);
  371                 simple_unlock(&nfsrv_reqcache_lock);
  372         }
  373 }
  374 
  375 /*
  376  * Clean out the cache. Called when the last nfsd terminates.
  377  */
  378 void
  379 nfsrv_cleancache()
  380 {
  381         struct nfsrvcache *rp, *nextrp;
  382 
  383         simple_lock(&nfsrv_reqcache_lock);
  384         for (rp = TAILQ_FIRST(&nfsrvlruhead); rp != 0; rp = nextrp) {
  385                 nextrp = TAILQ_NEXT(rp, rc_lru);
  386                 LIST_REMOVE(rp, rc_hash);
  387                 TAILQ_REMOVE(&nfsrvlruhead, rp, rc_lru);
  388                 KASSERT((rp->rc_flag & (RC_LOCKED|RC_WANTED)) == 0);
  389                 cleanentry(rp);
  390                 pool_put(&nfs_reqcache_pool, rp);
  391         }
  392         numnfsrvcache = 0;
  393         simple_unlock(&nfsrv_reqcache_lock);
  394 }

Cache object: 17c466f7106d8c21d593b830200a6c32


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