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 * %sccs.include.redist.c% 9 * 10 * @(#)nfs_srvcache.c 7.9 (Berkeley) 06/28/90 11 */ 12 13 /* 14 * Reference: Chet Juszczak, "Improving the Performance and Correctness 15 * of an NFS Server", in Proc. Winter 1989 USENIX Conference, 16 * pages 53-63. San Diego, February 1989. 17 */ 18 19 #include "param.h" 20 #include "user.h" 21 #include "vnode.h" 22 #include "mount.h" 23 #include "kernel.h" 24 #include "systm.h" 25 #include "mbuf.h" 26 #include "socket.h" 27 #include "socketvar.h" 28 #include "../netinet/in.h" 29 #include "nfsm_subs.h" 30 #include "nfsv2.h" 31 #include "nfsrvcache.h" 32 #include "nfs.h" 33 34 #if ((NFSRCHSZ&(NFSRCHSZ-1)) == 0) 35 #define NFSRCHASH(xid) (((xid)+((xid)>>16))&(NFSRCHSZ-1)) 36 #else 37 #define NFSRCHASH(xid) (((unsigned)((xid)+((xid)>>16)))%NFSRCHSZ) 38 #endif 39 40 union rhead { 41 union rhead *rh_head[2]; 42 struct nfsrvcache *rh_chain[2]; 43 } rhead[NFSRCHSZ]; 44 45 static struct nfsrvcache nfsrvcachehead; 46 static struct nfsrvcache nfsrvcache[NFSRVCACHESIZ]; 47 48 #define TRUE 1 49 #define FALSE 0 50 51 /* 52 * Static array that defines which nfs rpc's are nonidempotent 53 */ 54 int nonidempotent[NFS_NPROCS] = { 55 FALSE, 56 FALSE, 57 TRUE, 58 FALSE, 59 FALSE, 60 FALSE, 61 FALSE, 62 FALSE, 63 TRUE, 64 TRUE, 65 TRUE, 66 TRUE, 67 TRUE, 68 TRUE, 69 TRUE, 70 TRUE, 71 FALSE, 72 FALSE, 73 }; 74 75 /* True iff the rpc reply is an nfs status ONLY! */ 76 static int repliesstatus[NFS_NPROCS] = { 77 FALSE, 78 FALSE, 79 FALSE, 80 FALSE, 81 FALSE, 82 FALSE, 83 FALSE, 84 FALSE, 85 FALSE, 86 FALSE, 87 TRUE, 88 TRUE, 89 TRUE, 90 TRUE, 91 FALSE, 92 TRUE, 93 FALSE, 94 FALSE, 95 }; 96 97 /* 98 * Initialize the server request cache list 99 */ 100 nfsrv_initcache() 101 { 102 register int i; 103 register struct nfsrvcache *rp = nfsrvcache; 104 register struct nfsrvcache *hp = &nfsrvcachehead; 105 register union rhead *rh = rhead; 106 107 for (i = NFSRCHSZ; --i >= 0; rh++) { 108 rh->rh_head[0] = rh; 109 rh->rh_head[1] = rh; 110 } 111 hp->rc_next = hp->rc_prev = hp; 112 for (i = NFSRVCACHESIZ; i-- > 0; ) { 113 rp->rc_state = RC_UNUSED; 114 rp->rc_flag = 0; 115 rp->rc_forw = rp; 116 rp->rc_back = rp; 117 rp->rc_next = hp->rc_next; 118 hp->rc_next->rc_prev = rp; 119 rp->rc_prev = hp; 120 hp->rc_next = rp; 121 rp++; 122 } 123 } 124 125 /* 126 * Look for the request in the cache 127 * If found then 128 * return action and optionally reply 129 * else 130 * insert it in the cache 131 * 132 * The rules are as follows: 133 * - if in progress, return DROP request 134 * - if completed within DELAY of the current time, return DROP it 135 * - if completed a longer time ago return REPLY if the reply was cached or 136 * return DOIT 137 * Update/add new request at end of lru list 138 */ 139 nfsrv_getcache(nam, xid, proc, repp) 140 struct mbuf *nam; 141 u_long xid; 142 int proc; 143 struct mbuf **repp; 144 { 145 register struct nfsrvcache *rp; 146 register union rhead *rh; 147 struct mbuf *mb; 148 caddr_t bpos; 149 int ret; 150 151 rh = &rhead[NFSRCHASH(xid)]; 152 loop: 153 for (rp = rh->rh_chain[0]; rp != (struct nfsrvcache *)rh; rp = rp->rc_forw) { 154 if (xid == rp->rc_xid && proc == rp->rc_proc && 155 nfs_netaddr_match(nam, &rp->rc_nam)) { 156 if ((rp->rc_flag & RC_LOCKED) != 0) { 157 rp->rc_flag |= RC_WANTED; 158 (void) tsleep((caddr_t)rp, PZERO-1, "nfsrc", 0); 159 goto loop; 160 } 161 rp->rc_flag |= RC_LOCKED; 162 put_at_head(rp); 163 if (rp->rc_state == RC_UNUSED) 164 panic("nfsrv cache"); 165 if (rp->rc_state == RC_INPROG || 166 (time.tv_sec - rp->rc_timestamp) < RC_DELAY) { 167 nfsstats.srvcache_inproghits++; 168 ret = RC_DROPIT; 169 } else if (rp->rc_flag & RC_REPSTATUS) { 170 nfsstats.srvcache_idemdonehits++; 171 nfs_rephead(0, xid, rp->rc_status, repp, &mb, 172 &bpos); 173 rp->rc_timestamp = time.tv_sec; 174 ret = RC_REPLY; 175 } else if (rp->rc_flag & RC_REPMBUF) { 176 nfsstats.srvcache_idemdonehits++; 177 *repp = m_copym(rp->rc_reply, 0, M_COPYALL, 178 M_WAIT); 179 rp->rc_timestamp = time.tv_sec; 180 ret = RC_REPLY; 181 } else { 182 nfsstats.srvcache_nonidemdonehits++; 183 rp->rc_state = RC_INPROG; 184 ret = RC_DOIT; 185 } 186 rp->rc_flag &= ~RC_LOCKED; 187 if (rp->rc_flag & RC_WANTED) { 188 rp->rc_flag &= ~RC_WANTED; 189 wakeup((caddr_t)rp); 190 } 191 return (ret); 192 } 193 } 194 nfsstats.srvcache_misses++; 195 rp = nfsrvcachehead.rc_prev; 196 while ((rp->rc_flag & RC_LOCKED) != 0) { 197 rp->rc_flag |= RC_WANTED; 198 (void) tsleep((caddr_t)rp, PZERO-1, "nfsrc", 0); 199 } 200 remque(rp); 201 put_at_head(rp); 202 if (rp->rc_flag & RC_REPMBUF) 203 mb = rp->rc_reply; 204 else 205 mb = (struct mbuf *)0; 206 rp->rc_flag = 0; 207 rp->rc_state = RC_INPROG; 208 rp->rc_xid = xid; 209 bcopy((caddr_t)nam, (caddr_t)&rp->rc_nam, sizeof (struct mbuf)); 210 rp->rc_proc = proc; 211 insque(rp, rh); 212 if (mb) 213 m_freem(mb); 214 return (RC_DOIT); 215 } 216 217 /* 218 * Update a request cache entry after the rpc has been done 219 */ 220 nfsrv_updatecache(nam, xid, proc, repvalid, repstat, repmbuf) 221 struct mbuf *nam; 222 u_long xid; 223 int proc; 224 int repvalid; 225 int repstat; 226 struct mbuf *repmbuf; 227 { 228 register struct nfsrvcache *rp; 229 register union rhead *rh; 230 231 rh = &rhead[NFSRCHASH(xid)]; 232 loop: 233 for (rp = rh->rh_chain[0]; rp != (struct nfsrvcache *)rh; rp = rp->rc_forw) { 234 if (xid == rp->rc_xid && proc == rp->rc_proc && 235 nfs_netaddr_match(nam, &rp->rc_nam)) { 236 if ((rp->rc_flag & RC_LOCKED) != 0) { 237 rp->rc_flag |= RC_WANTED; 238 (void) tsleep((caddr_t)rp, PZERO-1, "nfsrc", 0); 239 goto loop; 240 } 241 rp->rc_flag |= RC_LOCKED; 242 rp->rc_state = RC_DONE; 243 /* 244 * If we have a valid reply update status and save 245 * the reply for non-idempotent rpc's. 246 * Otherwise invalidate entry by setting the timestamp 247 * to nil. 248 */ 249 if (repvalid) { 250 rp->rc_timestamp = time.tv_sec; 251 if (nonidempotent[proc]) { 252 if (repliesstatus[proc]) { 253 rp->rc_status = repstat; 254 rp->rc_flag |= RC_REPSTATUS; 255 } else { 256 rp->rc_reply = m_copym(repmbuf, 257 0, M_COPYALL, M_WAIT); 258 rp->rc_flag |= RC_REPMBUF; 259 } 260 } 261 } else { 262 rp->rc_timestamp = 0; 263 } 264 rp->rc_flag &= ~RC_LOCKED; 265 if (rp->rc_flag & RC_WANTED) { 266 rp->rc_flag &= ~RC_WANTED; 267 wakeup((caddr_t)rp); 268 } 269 return; 270 } 271 } 272 } 273