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Annotation of Net2/nfs/nfs_srvcache.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1989 The Regents of the University of California.
        !             3:  * All rights reserved.
        !             4:  *
        !             5:  * This code is derived from software contributed to Berkeley by
        !             6:  * Rick Macklem at The University of Guelph.
        !             7:  *
        !             8:  * Redistribution and use in source and binary forms, with or without
        !             9:  * modification, are permitted provided that the following conditions
        !            10:  * are met:
        !            11:  * 1. Redistributions of source code must retain the above copyright
        !            12:  *    notice, this list of conditions and the following disclaimer.
        !            13:  * 2. Redistributions in binary form must reproduce the above copyright
        !            14:  *    notice, this list of conditions and the following disclaimer in the
        !            15:  *    documentation and/or other materials provided with the distribution.
        !            16:  * 3. All advertising materials mentioning features or use of this software
        !            17:  *    must display the following acknowledgement:
        !            18:  *     This product includes software developed by the University of
        !            19:  *     California, Berkeley and its contributors.
        !            20:  * 4. Neither the name of the University nor the names of its contributors
        !            21:  *    may be used to endorse or promote products derived from this software
        !            22:  *    without specific prior written permission.
        !            23:  *
        !            24:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
        !            25:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            26:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            27:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
        !            28:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            29:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            30:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            31:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            32:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            33:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            34:  * SUCH DAMAGE.
        !            35:  *
        !            36:  *     @(#)nfs_srvcache.c      7.11 (Berkeley) 4/16/91
        !            37:  */
        !            38: 
        !            39: /*
        !            40:  * Reference: Chet Juszczak, "Improving the Performance and Correctness
        !            41:  *            of an NFS Server", in Proc. Winter 1989 USENIX Conference,
        !            42:  *            pages 53-63. San Diego, February 1989.
        !            43:  */
        !            44: 
        !            45: #include "param.h"
        !            46: #include "namei.h"
        !            47: #include "vnode.h"
        !            48: #include "mount.h"
        !            49: #include "kernel.h"
        !            50: #include "systm.h"
        !            51: #include "mbuf.h"
        !            52: #include "socket.h"
        !            53: #include "socketvar.h"
        !            54: 
        !            55: #include "../netinet/in.h"
        !            56: 
        !            57: #include "nfsm_subs.h"
        !            58: #include "nfsv2.h"
        !            59: #include "nfsrvcache.h"
        !            60: #include "nfs.h"
        !            61: 
        !            62: #if    ((NFSRCHSZ&(NFSRCHSZ-1)) == 0)
        !            63: #define        NFSRCHASH(xid)          (((xid)+((xid)>>16))&(NFSRCHSZ-1))
        !            64: #else
        !            65: #define        NFSRCHASH(xid)          (((unsigned)((xid)+((xid)>>16)))%NFSRCHSZ)
        !            66: #endif
        !            67: 
        !            68: union rhead {
        !            69:        union  rhead *rh_head[2];
        !            70:        struct nfsrvcache *rh_chain[2];
        !            71: } rhead[NFSRCHSZ];
        !            72: 
        !            73: static struct nfsrvcache nfsrvcachehead;
        !            74: static struct nfsrvcache nfsrvcache[NFSRVCACHESIZ];
        !            75: 
        !            76: #define TRUE   1
        !            77: #define        FALSE   0
        !            78: 
        !            79: /*
        !            80:  * Static array that defines which nfs rpc's are nonidempotent
        !            81:  */
        !            82: int nonidempotent[NFS_NPROCS] = {
        !            83:        FALSE,
        !            84:        FALSE,
        !            85:        TRUE,
        !            86:        FALSE,
        !            87:        FALSE,
        !            88:        FALSE,
        !            89:        FALSE,
        !            90:        FALSE,
        !            91:        TRUE,
        !            92:        TRUE,
        !            93:        TRUE,
        !            94:        TRUE,
        !            95:        TRUE,
        !            96:        TRUE,
        !            97:        TRUE,
        !            98:        TRUE,
        !            99:        FALSE,
        !           100:        FALSE,
        !           101: };
        !           102: 
        !           103: /* True iff the rpc reply is an nfs status ONLY! */
        !           104: static int repliesstatus[NFS_NPROCS] = {
        !           105:        FALSE,
        !           106:        FALSE,
        !           107:        FALSE,
        !           108:        FALSE,
        !           109:        FALSE,
        !           110:        FALSE,
        !           111:        FALSE,
        !           112:        FALSE,
        !           113:        FALSE,
        !           114:        FALSE,
        !           115:        TRUE,
        !           116:        TRUE,
        !           117:        TRUE,
        !           118:        TRUE,
        !           119:        FALSE,
        !           120:        TRUE,
        !           121:        FALSE,
        !           122:        FALSE,
        !           123: };
        !           124: 
        !           125: /*
        !           126:  * Initialize the server request cache list
        !           127:  */
        !           128: nfsrv_initcache()
        !           129: {
        !           130:        register int i;
        !           131:        register struct nfsrvcache *rp = nfsrvcache;
        !           132:        register struct nfsrvcache *hp = &nfsrvcachehead;
        !           133:        register union  rhead *rh = rhead;
        !           134: 
        !           135:        for (i = NFSRCHSZ; --i >= 0; rh++) {
        !           136:                rh->rh_head[0] = rh;
        !           137:                rh->rh_head[1] = rh;
        !           138:        }
        !           139:        hp->rc_next = hp->rc_prev = hp;
        !           140:        for (i = NFSRVCACHESIZ; i-- > 0; ) {
        !           141:                rp->rc_state = RC_UNUSED;
        !           142:                rp->rc_flag = 0;
        !           143:                rp->rc_forw = rp;
        !           144:                rp->rc_back = rp;
        !           145:                rp->rc_next = hp->rc_next;
        !           146:                hp->rc_next->rc_prev = rp;
        !           147:                rp->rc_prev = hp;
        !           148:                hp->rc_next = rp;
        !           149:                rp++;
        !           150:        }
        !           151: }
        !           152: 
        !           153: /*
        !           154:  * Look for the request in the cache
        !           155:  * If found then
        !           156:  *    return action and optionally reply
        !           157:  * else
        !           158:  *    insert it in the cache
        !           159:  *
        !           160:  * The rules are as follows:
        !           161:  * - if in progress, return DROP request
        !           162:  * - if completed within DELAY of the current time, return DROP it
        !           163:  * - if completed a longer time ago return REPLY if the reply was cached or
        !           164:  *   return DOIT
        !           165:  * Update/add new request at end of lru list
        !           166:  */
        !           167: nfsrv_getcache(nam, xid, proc, repp)
        !           168:        struct mbuf *nam;
        !           169:        u_long xid;
        !           170:        int proc;
        !           171:        struct mbuf **repp;
        !           172: {
        !           173:        register struct nfsrvcache *rp;
        !           174:        register union  rhead *rh;
        !           175:        struct mbuf *mb;
        !           176:        caddr_t bpos;
        !           177:        int ret;
        !           178: 
        !           179:        rh = &rhead[NFSRCHASH(xid)];
        !           180: loop:
        !           181:        for (rp = rh->rh_chain[0]; rp != (struct nfsrvcache *)rh; rp = rp->rc_forw) {
        !           182:                if (xid == rp->rc_xid && proc == rp->rc_proc &&
        !           183:                    nfs_netaddr_match(nam, &rp->rc_nam)) {
        !           184:                        if ((rp->rc_flag & RC_LOCKED) != 0) {
        !           185:                                rp->rc_flag |= RC_WANTED;
        !           186:                                (void) tsleep((caddr_t)rp, PZERO-1, "nfsrc", 0);
        !           187:                                goto loop;
        !           188:                        }
        !           189:                        rp->rc_flag |= RC_LOCKED;
        !           190:                        put_at_head(rp);
        !           191:                        if (rp->rc_state == RC_UNUSED)
        !           192:                                panic("nfsrv cache");
        !           193:                        if (rp->rc_state == RC_INPROG ||
        !           194:                           (time.tv_sec - rp->rc_timestamp) < RC_DELAY) {
        !           195:                                nfsstats.srvcache_inproghits++;
        !           196:                                ret = RC_DROPIT;
        !           197:                        } else if (rp->rc_flag & RC_REPSTATUS) {
        !           198:                                nfsstats.srvcache_idemdonehits++;
        !           199:                                nfs_rephead(0, xid, rp->rc_status, repp, &mb,
        !           200:                                        &bpos);
        !           201:                                rp->rc_timestamp = time.tv_sec;
        !           202:                                ret = RC_REPLY;
        !           203:                        } else if (rp->rc_flag & RC_REPMBUF) {
        !           204:                                nfsstats.srvcache_idemdonehits++;
        !           205:                                *repp = m_copym(rp->rc_reply, 0, M_COPYALL,
        !           206:                                                M_WAIT);
        !           207:                                rp->rc_timestamp = time.tv_sec;
        !           208:                                ret = RC_REPLY;
        !           209:                        } else {
        !           210:                                nfsstats.srvcache_nonidemdonehits++;
        !           211:                                rp->rc_state = RC_INPROG;
        !           212:                                ret = RC_DOIT;
        !           213:                        }
        !           214:                        rp->rc_flag &= ~RC_LOCKED;
        !           215:                        if (rp->rc_flag & RC_WANTED) {
        !           216:                                rp->rc_flag &= ~RC_WANTED;
        !           217:                                wakeup((caddr_t)rp);
        !           218:                        }
        !           219:                        return (ret);
        !           220:                }
        !           221:        }
        !           222:        nfsstats.srvcache_misses++;
        !           223:        rp = nfsrvcachehead.rc_prev;
        !           224:        while ((rp->rc_flag & RC_LOCKED) != 0) {
        !           225:                rp->rc_flag |= RC_WANTED;
        !           226:                (void) tsleep((caddr_t)rp, PZERO-1, "nfsrc", 0);
        !           227:        }
        !           228:        remque(rp);
        !           229:        put_at_head(rp);
        !           230:        if (rp->rc_flag & RC_REPMBUF)
        !           231:                mb = rp->rc_reply;
        !           232:        else
        !           233:                mb = (struct mbuf *)0;
        !           234:        rp->rc_flag = 0;
        !           235:        rp->rc_state = RC_INPROG;
        !           236:        rp->rc_xid = xid;
        !           237:        bcopy((caddr_t)nam, (caddr_t)&rp->rc_nam, sizeof (struct mbuf));
        !           238:        rp->rc_proc = proc;
        !           239:        insque(rp, rh);
        !           240:        if (mb)
        !           241:                m_freem(mb);
        !           242:        return (RC_DOIT);
        !           243: }
        !           244: 
        !           245: /*
        !           246:  * Update a request cache entry after the rpc has been done
        !           247:  */
        !           248: nfsrv_updatecache(nam, xid, proc, repvalid, repstat, repmbuf)
        !           249:        struct mbuf *nam;
        !           250:        u_long xid;
        !           251:        int proc;
        !           252:        int repvalid;
        !           253:        int repstat;
        !           254:        struct mbuf *repmbuf;
        !           255: {
        !           256:        register struct nfsrvcache *rp;
        !           257:        register union  rhead *rh;
        !           258: 
        !           259:        rh = &rhead[NFSRCHASH(xid)];
        !           260: loop:
        !           261:        for (rp = rh->rh_chain[0]; rp != (struct nfsrvcache *)rh; rp = rp->rc_forw) {
        !           262:                if (xid == rp->rc_xid && proc == rp->rc_proc &&
        !           263:                    nfs_netaddr_match(nam, &rp->rc_nam)) {
        !           264:                        if ((rp->rc_flag & RC_LOCKED) != 0) {
        !           265:                                rp->rc_flag |= RC_WANTED;
        !           266:                                (void) tsleep((caddr_t)rp, PZERO-1, "nfsrc", 0);
        !           267:                                goto loop;
        !           268:                        }
        !           269:                        rp->rc_flag |= RC_LOCKED;
        !           270:                        rp->rc_state = RC_DONE;
        !           271:                        /*
        !           272:                         * If we have a valid reply update status and save
        !           273:                         * the reply for non-idempotent rpc's.
        !           274:                         * Otherwise invalidate entry by setting the timestamp
        !           275:                         * to nil.
        !           276:                         */
        !           277:                        if (repvalid) {
        !           278:                                rp->rc_timestamp = time.tv_sec;
        !           279:                                if (nonidempotent[proc]) {
        !           280:                                        if (repliesstatus[proc]) {
        !           281:                                                rp->rc_status = repstat;
        !           282:                                                rp->rc_flag |= RC_REPSTATUS;
        !           283:                                        } else {
        !           284:                                                rp->rc_reply = m_copym(repmbuf,
        !           285:                                                        0, M_COPYALL, M_WAIT);
        !           286:                                                rp->rc_flag |= RC_REPMBUF;
        !           287:                                        }
        !           288:                                }
        !           289:                        } else {
        !           290:                                rp->rc_timestamp = 0;
        !           291:                        }
        !           292:                        rp->rc_flag &= ~RC_LOCKED;
        !           293:                        if (rp->rc_flag & RC_WANTED) {
        !           294:                                rp->rc_flag &= ~RC_WANTED;
        !           295:                                wakeup((caddr_t)rp);
        !           296:                        }
        !           297:                        return;
        !           298:                }
        !           299:        }
        !           300: }

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