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 * $Id: nfs_srvcache.c,v 1.1 94/10/20 10:57:33 root Exp $
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 "sys/param.h"
46 #include "sys/file.h"
47 #include "sys/mount.h"
48 #include "sys/time.h"
49 #include "uio.h"
50 #include "sys/errno.h" /* for inlines */
51 #include "proc.h"
52 #include "mbuf.h"
53 #include "socketvar.h"
54
55 #include "in.h"
56
57 #include "namei.h"
58 #include "vnode.h"
59 #include "nfs_msubs.h"
60 #include "nfs_v2.h"
61 #include "nfs_srvcache.h"
62 #include "nfs.h"
63 #include "prototypes.h" /* needs inlines */
64
65 #if ((NFSRCHSZ&(NFSRCHSZ-1)) == 0)
66 #define NFSRCHASH(xid) (((xid)+((xid)>>16))&(NFSRCHSZ-1))
67 #else
68 #define NFSRCHASH(xid) (((unsigned)((xid)+((xid)>>16)))%NFSRCHSZ)
69 #endif
70
71 union rhead {
72 union rhead *rh_head[2];
73 struct nfsrvcache *rh_chain[2];
74 } rhead[NFSRCHSZ];
75
76 static struct nfsrvcache nfsrvcachehead;
77 static struct nfsrvcache nfsrvcache[NFSRVCACHESIZ];
78
79 #define TRUE 1
80 #define FALSE 0
81
82 /*
83 * Static array that defines which nfs rpc's are nonidempotent
84 */
85 int nonidempotent[NFS_NPROCS] = {
86 FALSE,
87 FALSE,
88 TRUE,
89 FALSE,
90 FALSE,
91 FALSE,
92 FALSE,
93 FALSE,
94 TRUE,
95 TRUE,
96 TRUE,
97 TRUE,
98 TRUE,
99 TRUE,
100 TRUE,
101 TRUE,
102 FALSE,
103 FALSE,
104 };
105
106 /* True iff the rpc reply is an nfs status ONLY! */
107 static int repliesstatus[NFS_NPROCS] = {
108 FALSE,
109 FALSE,
110 FALSE,
111 FALSE,
112 FALSE,
113 FALSE,
114 FALSE,
115 FALSE,
116 FALSE,
117 FALSE,
118 TRUE,
119 TRUE,
120 TRUE,
121 TRUE,
122 FALSE,
123 TRUE,
124 FALSE,
125 FALSE,
126 };
127
128 /*
129 * Initialize the server request cache list
130 */
nfsrv_initcache()131 nfsrv_initcache()
132 {
133 register int i;
134 register struct nfsrvcache *rp = nfsrvcache;
135 register struct nfsrvcache *hp = &nfsrvcachehead;
136 register union rhead *rh = rhead;
137
138 for (i = NFSRCHSZ; --i >= 0; rh++) {
139 rh->rh_head[0] = rh;
140 rh->rh_head[1] = rh;
141 }
142 hp->rc_next = hp->rc_prev = hp;
143 for (i = NFSRVCACHESIZ; i-- > 0; ) {
144 rp->rc_state = RC_UNUSED;
145 rp->rc_flag = 0;
146 rp->rc_forw = rp;
147 rp->rc_back = rp;
148 rp->rc_next = hp->rc_next;
149 hp->rc_next->rc_prev = rp;
150 rp->rc_prev = hp;
151 hp->rc_next = rp;
152 rp++;
153 }
154 }
155
156 /*
157 * Look for the request in the cache
158 * If found then
159 * return action and optionally reply
160 * else
161 * insert it in the cache
162 *
163 * The rules are as follows:
164 * - if in progress, return DROP request
165 * - if completed within DELAY of the current time, return DROP it
166 * - if completed a longer time ago return REPLY if the reply was cached or
167 * return DOIT
168 * Update/add new request at end of lru list
169 */
170 nfsrv_getcache(nam, xid, proc, repp)
171 struct mbuf *nam;
172 u_long xid;
173 int proc;
174 struct mbuf **repp;
175 {
176 register struct nfsrvcache *rp;
177 register union rhead *rh;
178 struct mbuf *mb;
179 caddr_t bpos;
180 int ret;
181
182 rh = &rhead[NFSRCHASH(xid)];
183 loop:
184 for (rp = rh->rh_chain[0]; rp != (struct nfsrvcache *)rh; rp = rp->rc_forw) {
185 if (xid == rp->rc_xid && proc == rp->rc_proc &&
186 nfs_netaddr_match(nam, &rp->rc_nam)) {
187 if ((rp->rc_flag & RC_LOCKED) != 0) {
188 rp->rc_flag |= RC_WANTED;
189 (void) tsleep((caddr_t)rp, PSOCK-1, "nfsrc", 0);
190 goto loop;
191 }
192 rp->rc_flag |= RC_LOCKED;
193 put_at_head(rp);
194 if (rp->rc_state == RC_UNUSED)
195 panic("nfsrv cache");
196 if (rp->rc_state == RC_INPROG ||
197 (time.tv_sec - rp->rc_timestamp) < RC_DELAY) {
198 nfsstats.srvcache_inproghits++;
199 ret = RC_DROPIT;
200 } else if (rp->rc_flag & RC_REPSTATUS) {
201 nfsstats.srvcache_idemdonehits++;
202 nfs_rephead(0, xid, rp->rc_status, repp, &mb,
203 &bpos);
204 rp->rc_timestamp = time.tv_sec;
205 ret = RC_REPLY;
206 } else if (rp->rc_flag & RC_REPMBUF) {
207 nfsstats.srvcache_idemdonehits++;
208 *repp = m_copym(rp->rc_reply, 0, M_COPYALL,
209 M_WAIT);
210 rp->rc_timestamp = time.tv_sec;
211 ret = RC_REPLY;
212 } else {
213 nfsstats.srvcache_nonidemdonehits++;
214 rp->rc_state = RC_INPROG;
215 ret = RC_DOIT;
216 }
217 rp->rc_flag &= ~RC_LOCKED;
218 if (rp->rc_flag & RC_WANTED) {
219 rp->rc_flag &= ~RC_WANTED;
220 wakeup((caddr_t)rp);
221 }
222 return (ret);
223 }
224 }
225 nfsstats.srvcache_misses++;
226 rp = nfsrvcachehead.rc_prev;
227 while ((rp->rc_flag & RC_LOCKED) != 0) {
228 rp->rc_flag |= RC_WANTED;
229 (void) tsleep((caddr_t)rp, PSOCK-1, "nfsrc", 0);
230 }
231 remque(rp);
232 put_at_head(rp);
233 if (rp->rc_flag & RC_REPMBUF)
234 mb = rp->rc_reply;
235 else
236 mb = (struct mbuf *)0;
237 rp->rc_flag = 0;
238 rp->rc_state = RC_INPROG;
239 rp->rc_xid = xid;
240 memcpy((caddr_t)&rp->rc_nam, (caddr_t)nam, sizeof (struct mbuf));
241 rp->rc_proc = proc;
242 insque(rp, rh);
243 if (mb)
244 m_freem(mb);
245 return (RC_DOIT);
246 }
247
248 /*
249 * Update a request cache entry after the rpc has been done
250 */
251 nfsrv_updatecache(nam, xid, proc, repvalid, repstat, repmbuf)
252 struct mbuf *nam;
253 u_long xid;
254 int proc;
255 int repvalid;
256 int repstat;
257 struct mbuf *repmbuf;
258 {
259 register struct nfsrvcache *rp;
260 register union rhead *rh;
261
262 rh = &rhead[NFSRCHASH(xid)];
263 loop:
264 for (rp = rh->rh_chain[0]; rp != (struct nfsrvcache *)rh; rp = rp->rc_forw) {
265 if (xid == rp->rc_xid && proc == rp->rc_proc &&
266 nfs_netaddr_match(nam, &rp->rc_nam)) {
267 if ((rp->rc_flag & RC_LOCKED) != 0) {
268 rp->rc_flag |= RC_WANTED;
269 (void) tsleep((caddr_t)rp, PSOCK-1, "nfsrc", 0);
270 goto loop;
271 }
272 rp->rc_flag |= RC_LOCKED;
273 rp->rc_state = RC_DONE;
274 /*
275 * If we have a valid reply update status and save
276 * the reply for non-idempotent rpc's.
277 * Otherwise invalidate entry by setting the timestamp
278 * to nil.
279 */
280 if (repvalid) {
281 rp->rc_timestamp = time.tv_sec;
282 if (nonidempotent[proc]) {
283 if (repliesstatus[proc]) {
284 rp->rc_status = repstat;
285 rp->rc_flag |= RC_REPSTATUS;
286 } else {
287 rp->rc_reply = m_copym(repmbuf,
288 0, M_COPYALL, M_WAIT);
289 rp->rc_flag |= RC_REPMBUF;
290 }
291 }
292 } else {
293 rp->rc_timestamp = 0;
294 }
295 rp->rc_flag &= ~RC_LOCKED;
296 if (rp->rc_flag & RC_WANTED) {
297 rp->rc_flag &= ~RC_WANTED;
298 wakeup((caddr_t)rp);
299 }
300 return;
301 }
302 }
303 }
304