xref: /csrg-svn/sys/nfs/nfs_srvcache.c (revision 39759)
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	7.2 (Berkeley) 12/20/89
21  */
22 
23 #include "param.h"
24 #include "user.h"
25 #include "vnode.h"
26 #include "mount.h"
27 #include "kernel.h"
28 #include "systm.h"
29 #include "mbuf.h"
30 #include "socket.h"
31 #include "socketvar.h"
32 #include "netinet/in.h"
33 #include "nfsm_subs.h"
34 #include "nfsv2.h"
35 #include "nfsrvcache.h"
36 #include "nfs.h"
37 
38 #if	((NFSRCHSZ&(NFSRCHSZ-1)) == 0)
39 #define	NFSRCHASH(xid)		(((xid)+((xid)>>16))&(NFSRCHSZ-1))
40 #else
41 #define	NFSRCHASH(xid)		(((unsigned)((xid)+((xid)>>16)))%NFSRCHSZ)
42 #endif
43 
44 union rhead {
45 	union  rhead *rh_head[2];
46 	struct nfsrvcache *rh_chain[2];
47 } rhead[NFSRCHSZ];
48 
49 static struct nfsrvcache nfsrvcachehead;
50 static struct nfsrvcache nfsrvcache[NFSRVCACHESIZ];
51 
52 #define TRUE	1
53 #define	FALSE	0
54 
55 /*
56  * Static array that defines which nfs rpc's are nonidempotent
57  */
58 static int nonidempotent[NFS_NPROCS] = {
59 	FALSE,
60 	FALSE,
61 	TRUE,
62 	FALSE,
63 	FALSE,
64 	FALSE,
65 	FALSE,
66 	FALSE,
67 	TRUE,
68 	TRUE,
69 	TRUE,
70 	TRUE,
71 	TRUE,
72 	TRUE,
73 	TRUE,
74 	TRUE,
75 	FALSE,
76 	FALSE,
77 };
78 
79 /* True iff the rpc reply is an nfs status ONLY! */
80 static int repliesstatus[NFS_NPROCS] = {
81 	FALSE,
82 	FALSE,
83 	FALSE,
84 	FALSE,
85 	FALSE,
86 	FALSE,
87 	FALSE,
88 	FALSE,
89 	FALSE,
90 	FALSE,
91 	TRUE,
92 	TRUE,
93 	TRUE,
94 	TRUE,
95 	FALSE,
96 	TRUE,
97 	FALSE,
98 	FALSE,
99 };
100 
101 /*
102  * Initialize the server request cache list
103  */
104 nfsrv_initcache()
105 {
106 	register int i;
107 	register struct nfsrvcache *rp = nfsrvcache;
108 	register struct nfsrvcache *hp = &nfsrvcachehead;
109 	register union  rhead *rh = rhead;
110 
111 	for (i = NFSRCHSZ; --i >= 0; rh++) {
112 		rh->rh_head[0] = rh;
113 		rh->rh_head[1] = rh;
114 	}
115 	hp->rc_next = hp->rc_prev = hp;
116 	for (i = NFSRVCACHESIZ; i-- > 0; ) {
117 		rp->rc_state = RC_UNUSED;
118 		rp->rc_flag = 0;
119 		rp->rc_forw = rp;
120 		rp->rc_back = rp;
121 		rp->rc_next = hp->rc_next;
122 		hp->rc_next->rc_prev = rp;
123 		rp->rc_prev = hp;
124 		hp->rc_next = rp;
125 		rp++;
126 	}
127 }
128 
129 /*
130  * Look for the request in the cache
131  * If found then
132  *    return action and optionally reply
133  * else
134  *    insert it in the cache
135  *
136  * The rules are as follows:
137  * - if in progress, return DROP request
138  * - if completed within DELAY of the current time, return DROP it
139  * - if completed a longer time ago return REPLY if the reply was cached or
140  *   return DOIT
141  * Update/add new request at end of lru list
142  */
143 nfsrv_getcache(nam, xid, proc, repp)
144 	struct mbuf *nam;
145 	u_long xid;
146 	int proc;
147 	struct mbuf **repp;
148 {
149 	register struct nfsrvcache *rp;
150 	register union  rhead *rh;
151 	register u_long saddr;
152 	struct mbuf *mb;
153 	caddr_t bpos;
154 	int ret;
155 
156 	rh = &rhead[NFSRCHASH(xid)];
157 	saddr = mtod(nam, struct sockaddr_in *)->sin_addr.s_addr;
158 loop:
159 	for (rp = rh->rh_chain[0]; rp != (struct nfsrvcache *)rh; rp = rp->rc_forw) {
160 		if (xid == rp->rc_xid && saddr == rp->rc_saddr &&
161 		    proc == rp->rc_proc) {
162 			if ((rp->rc_flag & RC_LOCKED) != 0) {
163 				rp->rc_flag |= RC_WANTED;
164 				sleep((caddr_t)rp, PZERO-1);
165 				goto loop;
166 			}
167 			rp->rc_flag |= RC_LOCKED;
168 			put_at_head(rp);
169 			if (rp->rc_state == RC_UNUSED)
170 				panic("nfsrv cache");
171 			if (rp->rc_state == RC_INPROG ||
172 			   (time.tv_sec - rp->rc_timestamp) < RC_DELAY) {
173 				nfsstats.srvcache_inproghits++;
174 				ret = RC_DROPIT;
175 			} else if (rp->rc_flag & RC_REPSTATUS) {
176 				nfsstats.srvcache_idemdonehits++;
177 				nfs_rephead(0, xid, rp->rc_status, repp, &mb,
178 					&bpos);
179 				rp->rc_timestamp = time.tv_sec;
180 				ret = RC_REPLY;
181 			} else if (rp->rc_flag & RC_REPMBUF) {
182 				nfsstats.srvcache_idemdonehits++;
183 				*repp = NFSMCOPY(rp->rc_reply, 0, M_COPYALL,
184 						M_WAIT);
185 				rp->rc_timestamp = time.tv_sec;
186 				ret = RC_REPLY;
187 			} else {
188 				nfsstats.srvcache_nonidemdonehits++;
189 				rp->rc_state = RC_INPROG;
190 				ret = RC_DOIT;
191 			}
192 			rp->rc_flag &= ~RC_LOCKED;
193 			if (rp->rc_flag & RC_WANTED) {
194 				rp->rc_flag &= ~RC_WANTED;
195 				wakeup((caddr_t)rp);
196 			}
197 			return (ret);
198 		}
199 	}
200 	nfsstats.srvcache_misses++;
201 	rp = nfsrvcachehead.rc_prev;
202 	while ((rp->rc_flag & RC_LOCKED) != 0) {
203 		rp->rc_flag |= RC_WANTED;
204 		sleep((caddr_t)rp, PZERO-1);
205 	}
206 	remque(rp);
207 	put_at_head(rp);
208 	if (rp->rc_flag & RC_REPMBUF)
209 		mb = rp->rc_reply;
210 	else
211 		mb = (struct mbuf *)0;
212 	rp->rc_flag = 0;
213 	rp->rc_state = RC_INPROG;
214 	rp->rc_xid = xid;
215 	rp->rc_saddr = saddr;
216 	rp->rc_proc = proc;
217 	insque(rp, rh);
218 	if (mb)
219 		m_freem(mb);
220 	return (RC_DOIT);
221 }
222 
223 /*
224  * Update a request cache entry after the rpc has been done
225  */
226 nfsrv_updatecache(nam, xid, proc, repstat, repmbuf)
227 	struct mbuf *nam;
228 	u_long xid;
229 	int proc;
230 	int repstat;
231 	struct mbuf *repmbuf;
232 {
233 	register struct nfsrvcache *rp;
234 	register union	rhead *rh;
235 	register u_long saddr;
236 
237 	rh = &rhead[NFSRCHASH(xid)];
238 	saddr = mtod(nam, struct sockaddr_in *)->sin_addr.s_addr;
239 loop:
240 	for (rp = rh->rh_chain[0]; rp != (struct nfsrvcache *)rh; rp = rp->rc_forw) {
241 		if (xid == rp->rc_xid && saddr == rp->rc_saddr &&
242 		    proc == rp->rc_proc) {
243 			if ((rp->rc_flag & RC_LOCKED) != 0) {
244 				rp->rc_flag |= RC_WANTED;
245 				sleep((caddr_t)rp, PZERO-1);
246 				goto loop;
247 			}
248 			rp->rc_flag |= RC_LOCKED;
249 			rp->rc_state = RC_DONE;
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 = NFSMCOPY(repmbuf, 0,
257 							M_COPYALL, M_WAIT);
258 					rp->rc_flag |= RC_REPMBUF;
259 				}
260 			}
261 			rp->rc_flag &= ~RC_LOCKED;
262 			if (rp->rc_flag & RC_WANTED) {
263 				rp->rc_flag &= ~RC_WANTED;
264 				wakeup((caddr_t)rp);
265 			}
266 			return;
267 		}
268 	}
269 }
270