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 are permitted 9 * provided that the above copyright notice and this paragraph are 10 * duplicated in all such forms and that any documentation, 11 * advertising materials, and other materials related to such 12 * distribution and use acknowledge that the software was developed 13 * by the University of California, Berkeley. The name of the 14 * University may not be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 19 * 20 * @(#)nfs_srvcache.c 7.8 (Berkeley) 06/22/90 21 */ 22 23 /* 24 * Reference: Chet Juszczak, "Improving the Performance and Correctness 25 * of an NFS Server", in Proc. Winter 1989 USENIX Conference, 26 * pages 53-63. San Diego, February 1989. 27 */ 28 29 #include "param.h" 30 #include "user.h" 31 #include "vnode.h" 32 #include "mount.h" 33 #include "kernel.h" 34 #include "systm.h" 35 #include "mbuf.h" 36 #include "socket.h" 37 #include "socketvar.h" 38 #include "../netinet/in.h" 39 #include "nfsm_subs.h" 40 #include "nfsv2.h" 41 #include "nfsrvcache.h" 42 #include "nfs.h" 43 44 #if ((NFSRCHSZ&(NFSRCHSZ-1)) == 0) 45 #define NFSRCHASH(xid) (((xid)+((xid)>>16))&(NFSRCHSZ-1)) 46 #else 47 #define NFSRCHASH(xid) (((unsigned)((xid)+((xid)>>16)))%NFSRCHSZ) 48 #endif 49 50 union rhead { 51 union rhead *rh_head[2]; 52 struct nfsrvcache *rh_chain[2]; 53 } rhead[NFSRCHSZ]; 54 55 static struct nfsrvcache nfsrvcachehead; 56 static struct nfsrvcache nfsrvcache[NFSRVCACHESIZ]; 57 58 #define TRUE 1 59 #define FALSE 0 60 61 /* 62 * Static array that defines which nfs rpc's are nonidempotent 63 */ 64 int nonidempotent[NFS_NPROCS] = { 65 FALSE, 66 FALSE, 67 TRUE, 68 FALSE, 69 FALSE, 70 FALSE, 71 FALSE, 72 FALSE, 73 TRUE, 74 TRUE, 75 TRUE, 76 TRUE, 77 TRUE, 78 TRUE, 79 TRUE, 80 TRUE, 81 FALSE, 82 FALSE, 83 }; 84 85 /* True iff the rpc reply is an nfs status ONLY! */ 86 static int repliesstatus[NFS_NPROCS] = { 87 FALSE, 88 FALSE, 89 FALSE, 90 FALSE, 91 FALSE, 92 FALSE, 93 FALSE, 94 FALSE, 95 FALSE, 96 FALSE, 97 TRUE, 98 TRUE, 99 TRUE, 100 TRUE, 101 FALSE, 102 TRUE, 103 FALSE, 104 FALSE, 105 }; 106 107 /* 108 * Initialize the server request cache list 109 */ 110 nfsrv_initcache() 111 { 112 register int i; 113 register struct nfsrvcache *rp = nfsrvcache; 114 register struct nfsrvcache *hp = &nfsrvcachehead; 115 register union rhead *rh = rhead; 116 117 for (i = NFSRCHSZ; --i >= 0; rh++) { 118 rh->rh_head[0] = rh; 119 rh->rh_head[1] = rh; 120 } 121 hp->rc_next = hp->rc_prev = hp; 122 for (i = NFSRVCACHESIZ; i-- > 0; ) { 123 rp->rc_state = RC_UNUSED; 124 rp->rc_flag = 0; 125 rp->rc_forw = rp; 126 rp->rc_back = rp; 127 rp->rc_next = hp->rc_next; 128 hp->rc_next->rc_prev = rp; 129 rp->rc_prev = hp; 130 hp->rc_next = rp; 131 rp++; 132 } 133 } 134 135 /* 136 * Look for the request in the cache 137 * If found then 138 * return action and optionally reply 139 * else 140 * insert it in the cache 141 * 142 * The rules are as follows: 143 * - if in progress, return DROP request 144 * - if completed within DELAY of the current time, return DROP it 145 * - if completed a longer time ago return REPLY if the reply was cached or 146 * return DOIT 147 * Update/add new request at end of lru list 148 */ 149 nfsrv_getcache(nam, xid, proc, repp) 150 struct mbuf *nam; 151 u_long xid; 152 int proc; 153 struct mbuf **repp; 154 { 155 register struct nfsrvcache *rp; 156 register union rhead *rh; 157 struct mbuf *mb; 158 caddr_t bpos; 159 int ret; 160 161 rh = &rhead[NFSRCHASH(xid)]; 162 loop: 163 for (rp = rh->rh_chain[0]; rp != (struct nfsrvcache *)rh; rp = rp->rc_forw) { 164 if (xid == rp->rc_xid && proc == rp->rc_proc && 165 nfs_netaddr_match(nam, &rp->rc_nam)) { 166 if ((rp->rc_flag & RC_LOCKED) != 0) { 167 rp->rc_flag |= RC_WANTED; 168 (void) tsleep((caddr_t)rp, PZERO-1, "nfsrc", 0); 169 goto loop; 170 } 171 rp->rc_flag |= RC_LOCKED; 172 put_at_head(rp); 173 if (rp->rc_state == RC_UNUSED) 174 panic("nfsrv cache"); 175 if (rp->rc_state == RC_INPROG || 176 (time.tv_sec - rp->rc_timestamp) < RC_DELAY) { 177 nfsstats.srvcache_inproghits++; 178 ret = RC_DROPIT; 179 } else if (rp->rc_flag & RC_REPSTATUS) { 180 nfsstats.srvcache_idemdonehits++; 181 nfs_rephead(0, xid, rp->rc_status, repp, &mb, 182 &bpos); 183 rp->rc_timestamp = time.tv_sec; 184 ret = RC_REPLY; 185 } else if (rp->rc_flag & RC_REPMBUF) { 186 nfsstats.srvcache_idemdonehits++; 187 *repp = m_copym(rp->rc_reply, 0, M_COPYALL, 188 M_WAIT); 189 rp->rc_timestamp = time.tv_sec; 190 ret = RC_REPLY; 191 } else { 192 nfsstats.srvcache_nonidemdonehits++; 193 rp->rc_state = RC_INPROG; 194 ret = RC_DOIT; 195 } 196 rp->rc_flag &= ~RC_LOCKED; 197 if (rp->rc_flag & RC_WANTED) { 198 rp->rc_flag &= ~RC_WANTED; 199 wakeup((caddr_t)rp); 200 } 201 return (ret); 202 } 203 } 204 nfsstats.srvcache_misses++; 205 rp = nfsrvcachehead.rc_prev; 206 while ((rp->rc_flag & RC_LOCKED) != 0) { 207 rp->rc_flag |= RC_WANTED; 208 (void) tsleep((caddr_t)rp, PZERO-1, "nfsrc", 0); 209 } 210 remque(rp); 211 put_at_head(rp); 212 if (rp->rc_flag & RC_REPMBUF) 213 mb = rp->rc_reply; 214 else 215 mb = (struct mbuf *)0; 216 rp->rc_flag = 0; 217 rp->rc_state = RC_INPROG; 218 rp->rc_xid = xid; 219 bcopy((caddr_t)nam, (caddr_t)&rp->rc_nam, sizeof (struct mbuf)); 220 rp->rc_proc = proc; 221 insque(rp, rh); 222 if (mb) 223 m_freem(mb); 224 return (RC_DOIT); 225 } 226 227 /* 228 * Update a request cache entry after the rpc has been done 229 */ 230 nfsrv_updatecache(nam, xid, proc, repvalid, repstat, repmbuf) 231 struct mbuf *nam; 232 u_long xid; 233 int proc; 234 int repvalid; 235 int repstat; 236 struct mbuf *repmbuf; 237 { 238 register struct nfsrvcache *rp; 239 register union rhead *rh; 240 241 rh = &rhead[NFSRCHASH(xid)]; 242 loop: 243 for (rp = rh->rh_chain[0]; rp != (struct nfsrvcache *)rh; rp = rp->rc_forw) { 244 if (xid == rp->rc_xid && proc == rp->rc_proc && 245 nfs_netaddr_match(nam, &rp->rc_nam)) { 246 if ((rp->rc_flag & RC_LOCKED) != 0) { 247 rp->rc_flag |= RC_WANTED; 248 (void) tsleep((caddr_t)rp, PZERO-1, "nfsrc", 0); 249 goto loop; 250 } 251 rp->rc_flag |= RC_LOCKED; 252 rp->rc_state = RC_DONE; 253 /* 254 * If we have a valid reply update status and save 255 * the reply for non-idempotent rpc's. 256 * Otherwise invalidate entry by setting the timestamp 257 * to nil. 258 */ 259 if (repvalid) { 260 rp->rc_timestamp = time.tv_sec; 261 if (nonidempotent[proc]) { 262 if (repliesstatus[proc]) { 263 rp->rc_status = repstat; 264 rp->rc_flag |= RC_REPSTATUS; 265 } else { 266 rp->rc_reply = m_copym(repmbuf, 267 0, M_COPYALL, M_WAIT); 268 rp->rc_flag |= RC_REPMBUF; 269 } 270 } 271 } else { 272 rp->rc_timestamp = 0; 273 } 274 rp->rc_flag &= ~RC_LOCKED; 275 if (rp->rc_flag & RC_WANTED) { 276 rp->rc_flag &= ~RC_WANTED; 277 wakeup((caddr_t)rp); 278 } 279 return; 280 } 281 } 282 } 283