The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: 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 1.30.2.1 2004/06/05 20:42:06 jdc 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 1.30.2.1 2004/06/05 20:42:06 jdc 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 /*
  146  * Initialize the server request cache list
  147  */
  148 void
  149 nfsrv_initcache()
  150 {
  151 
  152         nfsrvhashtbl = hashinit(desirednfsrvcache, HASH_LIST, M_NFSD,
  153             M_WAITOK, &nfsrvhash);
  154         TAILQ_INIT(&nfsrvlruhead);
  155         pool_init(&nfs_reqcache_pool, sizeof(struct nfsrvcache), 0, 0, 0,
  156             "nfsreqcachepl", &pool_allocator_nointr);
  157 }
  158 
  159 /*
  160  * Lookup a cache and lock it
  161  */
  162 static struct nfsrvcache *
  163 nfsrv_lookupcache(nd)
  164         struct nfsrv_descript *nd;
  165 {
  166         struct nfsrvcache *rp;
  167 
  168         LOCK_ASSERT(simple_lock_held(&nfsrv_reqcache_lock));
  169 
  170 loop:
  171         LIST_FOREACH(rp, NFSRCHASH(nd->nd_retxid), rc_hash) {
  172                 if (nd->nd_retxid == rp->rc_xid &&
  173                     nd->nd_procnum == rp->rc_proc &&
  174                     netaddr_match(NETFAMILY(rp), &rp->rc_haddr, nd->nd_nam)) {
  175                         if ((rp->rc_flag & RC_LOCKED) != 0) {
  176                                 rp->rc_flag |= RC_WANTED;
  177                                 (void) ltsleep(rp, PZERO - 1, "nfsrc", 0,
  178                                     &nfsrv_reqcache_lock);
  179                                 goto loop;
  180                         }
  181                         rp->rc_flag |= RC_LOCKED;
  182                         break;
  183                 }
  184         }
  185 
  186         return rp;
  187 }
  188 
  189 /*
  190  * Unlock a cache
  191  */
  192 static void
  193 nfsrv_unlockcache(rp)
  194         struct nfsrvcache *rp;
  195 {
  196 
  197         LOCK_ASSERT(simple_lock_held(&nfsrv_reqcache_lock));
  198 
  199         rp->rc_flag &= ~RC_LOCKED;
  200         if (rp->rc_flag & RC_WANTED) {
  201                 rp->rc_flag &= ~RC_WANTED;
  202                 wakeup(rp);
  203         }
  204 }
  205 
  206 /*
  207  * Look for the request in the cache
  208  * If found then
  209  *    return action and optionally reply
  210  * else
  211  *    insert it in the cache
  212  *
  213  * The rules are as follows:
  214  * - if in progress, return DROP request
  215  * - if completed within DELAY of the current time, return DROP it
  216  * - if completed a longer time ago return REPLY if the reply was cached or
  217  *   return DOIT
  218  * Update/add new request at end of lru list
  219  */
  220 int
  221 nfsrv_getcache(nd, slp, repp)
  222         struct nfsrv_descript *nd;
  223         struct nfssvc_sock *slp;
  224         struct mbuf **repp;
  225 {
  226         struct nfsrvcache *rp, *rpdup;
  227         struct mbuf *mb;
  228         struct sockaddr_in *saddr;
  229         caddr_t bpos;
  230         int ret;
  231 
  232         simple_lock(&nfsrv_reqcache_lock);
  233         rp = nfsrv_lookupcache(nd);
  234         if (rp) {
  235                 simple_unlock(&nfsrv_reqcache_lock);
  236 found:
  237                 /* If not at end of LRU chain, move it there */
  238                 if (TAILQ_NEXT(rp, rc_lru)) { /* racy but ok */
  239                         simple_lock(&nfsrv_reqcache_lock);
  240                         TAILQ_REMOVE(&nfsrvlruhead, rp, rc_lru);
  241                         TAILQ_INSERT_TAIL(&nfsrvlruhead, rp, rc_lru);
  242                         simple_unlock(&nfsrv_reqcache_lock);
  243                 }
  244                 if (rp->rc_state == RC_UNUSED)
  245                         panic("nfsrv cache");
  246                 if (rp->rc_state == RC_INPROG) {
  247                         nfsstats.srvcache_inproghits++;
  248                         ret = RC_DROPIT;
  249                 } else if (rp->rc_flag & RC_REPSTATUS) {
  250                         nfsstats.srvcache_nonidemdonehits++;
  251                         nfs_rephead(0, nd, slp, rp->rc_status,
  252                            0, (u_quad_t *)0, repp, &mb, &bpos);
  253                         ret = RC_REPLY;
  254                 } else if (rp->rc_flag & RC_REPMBUF) {
  255                         nfsstats.srvcache_nonidemdonehits++;
  256                         *repp = m_copym(rp->rc_reply, 0, M_COPYALL,
  257                                         M_WAIT);
  258                         ret = RC_REPLY;
  259                 } else {
  260                         nfsstats.srvcache_idemdonehits++;
  261                         rp->rc_state = RC_INPROG;
  262                         ret = RC_DOIT;
  263                 }
  264                 simple_lock(&nfsrv_reqcache_lock);
  265                 nfsrv_unlockcache(rp);
  266                 simple_unlock(&nfsrv_reqcache_lock);
  267                 return ret;
  268         }
  269         nfsstats.srvcache_misses++;
  270         if (numnfsrvcache < desirednfsrvcache) {
  271                 numnfsrvcache++;
  272                 simple_unlock(&nfsrv_reqcache_lock);
  273                 rp = pool_get(&nfs_reqcache_pool, PR_WAITOK);
  274                 memset(rp, 0, sizeof *rp);
  275                 rp->rc_flag = RC_LOCKED;
  276         } else {
  277                 rp = TAILQ_FIRST(&nfsrvlruhead);
  278                 while ((rp->rc_flag & RC_LOCKED) != 0) {
  279                         rp->rc_flag |= RC_WANTED;
  280                         (void) ltsleep(rp, PZERO-1, "nfsrc", 0,
  281                             &nfsrv_reqcache_lock);
  282                         rp = TAILQ_FIRST(&nfsrvlruhead);
  283                 }
  284                 rp->rc_flag |= RC_LOCKED;
  285                 LIST_REMOVE(rp, rc_hash);
  286                 TAILQ_REMOVE(&nfsrvlruhead, rp, rc_lru);
  287                 simple_unlock(&nfsrv_reqcache_lock);
  288                 if (rp->rc_flag & RC_REPMBUF)
  289                         m_freem(rp->rc_reply);
  290                 if (rp->rc_flag & RC_NAM)
  291                         (void) m_free(rp->rc_nam);
  292                 rp->rc_flag &= (RC_LOCKED | RC_WANTED);
  293         }
  294         rp->rc_state = RC_INPROG;
  295         rp->rc_xid = nd->nd_retxid;
  296         saddr = mtod(nd->nd_nam, struct sockaddr_in *);
  297         switch (saddr->sin_family) {
  298         case AF_INET:
  299                 rp->rc_flag |= RC_INETADDR;
  300                 rp->rc_inetaddr = saddr->sin_addr.s_addr;
  301                 break;
  302         case AF_ISO:
  303         default:
  304                 rp->rc_flag |= RC_NAM;
  305                 rp->rc_nam = m_copym(nd->nd_nam, 0, M_COPYALL, M_WAIT);
  306                 break;
  307         };
  308         rp->rc_proc = nd->nd_procnum;
  309         simple_lock(&nfsrv_reqcache_lock);
  310         rpdup = nfsrv_lookupcache(nd);
  311         if (rpdup != NULL) {
  312                 /*
  313                  * other thread made duplicate cache entry.
  314                  */
  315                 simple_unlock(&nfsrv_reqcache_lock);
  316                 pool_put(&nfs_reqcache_pool, rp);
  317                 rp = rpdup;
  318                 goto found;
  319         }
  320         TAILQ_INSERT_TAIL(&nfsrvlruhead, rp, rc_lru);
  321         LIST_INSERT_HEAD(NFSRCHASH(nd->nd_retxid), rp, rc_hash);
  322         nfsrv_unlockcache(rp);
  323         simple_unlock(&nfsrv_reqcache_lock);
  324         return RC_DOIT;
  325 }
  326 
  327 /*
  328  * Update a request cache entry after the rpc has been done
  329  */
  330 void
  331 nfsrv_updatecache(nd, repvalid, repmbuf)
  332         struct nfsrv_descript *nd;
  333         int repvalid;
  334         struct mbuf *repmbuf;
  335 {
  336         struct nfsrvcache *rp;
  337 
  338         if (!nd->nd_nam2)
  339                 return;
  340         simple_lock(&nfsrv_reqcache_lock);
  341         rp = nfsrv_lookupcache(nd);
  342         simple_unlock(&nfsrv_reqcache_lock);
  343         if (rp) {
  344                 rp->rc_state = RC_DONE;
  345                 /*
  346                  * If we have a valid reply update status and save
  347                  * the reply for non-idempotent rpc's.
  348                  */
  349                 if (repvalid && nonidempotent[nd->nd_procnum]) {
  350                         if ((nd->nd_flag & ND_NFSV3) == 0 &&
  351                           nfsv2_repstat[nfsv2_procid[nd->nd_procnum]]) {
  352                                 rp->rc_status = nd->nd_repstat;
  353                                 rp->rc_flag |= RC_REPSTATUS;
  354                         } else {
  355                                 rp->rc_reply = m_copym(repmbuf,
  356                                         0, M_COPYALL, M_WAIT);
  357                                 rp->rc_flag |= RC_REPMBUF;
  358                         }
  359                 }
  360                 simple_lock(&nfsrv_reqcache_lock);
  361                 nfsrv_unlockcache(rp);
  362                 simple_unlock(&nfsrv_reqcache_lock);
  363         }
  364 }
  365 
  366 /*
  367  * Clean out the cache. Called when the last nfsd terminates.
  368  */
  369 void
  370 nfsrv_cleancache()
  371 {
  372         struct nfsrvcache *rp, *nextrp;
  373 
  374         simple_lock(&nfsrv_reqcache_lock);
  375         for (rp = TAILQ_FIRST(&nfsrvlruhead); rp != 0; rp = nextrp) {
  376                 nextrp = TAILQ_NEXT(rp, rc_lru);
  377                 LIST_REMOVE(rp, rc_hash);
  378                 TAILQ_REMOVE(&nfsrvlruhead, rp, rc_lru);
  379                 pool_put(&nfs_reqcache_pool, rp);
  380         }
  381         numnfsrvcache = 0;
  382         simple_unlock(&nfsrv_reqcache_lock);
  383 }

Cache object: 05ca0b69cb15c3c19d8c52aa4d395ac1


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