NetBSD/sys/nfs/nfs_srvcache.c

282 lines
7.5 KiB
C

/*
* Copyright (c) 1989 The Regents of the University of California.
* All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Rick Macklem at The University of Guelph.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#)nfs_srvcache.c 7.11 (Berkeley) 4/16/91
* $Id: nfs_srvcache.c,v 1.6 1993/12/18 00:45:20 mycroft Exp $
*/
/*
* Reference: Chet Juszczak, "Improving the Performance and Correctness
* of an NFS Server", in Proc. Winter 1989 USENIX Conference,
* pages 53-63. San Diego, February 1989.
*/
#include <sys/param.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <netinet/in.h>
#include <nfs/nfsm_subs.h>
#include <nfs/nfsv2.h>
#include <nfs/nfsrvcache.h>
#include <nfs/nfs.h>
#if ((NFSRCHSZ&(NFSRCHSZ-1)) == 0)
#define NFSRCHASH(xid) (((xid)+((xid)>>16))&(NFSRCHSZ-1))
#else
#define NFSRCHASH(xid) (((unsigned)((xid)+((xid)>>16)))%NFSRCHSZ)
#endif
extern int nonidempotent[NFS_NPROCS];
union rhead {
union rhead *rh_head[2];
struct nfsrvcache *rh_chain[2];
} rhead[NFSRCHSZ];
static struct nfsrvcache nfsrvcachehead;
static struct nfsrvcache nfsrvcache[NFSRVCACHESIZ];
#define TRUE 1
#define FALSE 0
/* True iff the rpc reply is an nfs status ONLY! */
static int repliesstatus[NFS_NPROCS] = {
FALSE,
FALSE,
FALSE,
FALSE,
FALSE,
FALSE,
FALSE,
FALSE,
FALSE,
FALSE,
TRUE,
TRUE,
TRUE,
TRUE,
FALSE,
TRUE,
FALSE,
FALSE,
};
/*
* Initialize the server request cache list
*/
nfsrv_initcache()
{
register int i;
register struct nfsrvcache *rp = nfsrvcache;
register struct nfsrvcache *hp = &nfsrvcachehead;
register union rhead *rh = rhead;
for (i = NFSRCHSZ; --i >= 0; rh++) {
rh->rh_head[0] = rh;
rh->rh_head[1] = rh;
}
hp->rc_next = hp->rc_prev = hp;
for (i = NFSRVCACHESIZ; i-- > 0; ) {
rp->rc_state = RC_UNUSED;
rp->rc_flag = 0;
rp->rc_forw = rp;
rp->rc_back = rp;
rp->rc_next = hp->rc_next;
hp->rc_next->rc_prev = rp;
rp->rc_prev = hp;
hp->rc_next = rp;
rp++;
}
}
/*
* Look for the request in the cache
* If found then
* return action and optionally reply
* else
* insert it in the cache
*
* The rules are as follows:
* - if in progress, return DROP request
* - if completed within DELAY of the current time, return DROP it
* - if completed a longer time ago return REPLY if the reply was cached or
* return DOIT
* Update/add new request at end of lru list
*/
nfsrv_getcache(nam, xid, proc, repp)
struct mbuf *nam;
u_long xid;
int proc;
struct mbuf **repp;
{
register struct nfsrvcache *rp;
register union rhead *rh;
struct mbuf *mb;
caddr_t bpos;
int ret;
rh = &rhead[NFSRCHASH(xid)];
loop:
for (rp = rh->rh_chain[0]; rp != (struct nfsrvcache *)rh; rp = rp->rc_forw) {
if (xid == rp->rc_xid && proc == rp->rc_proc &&
nfs_netaddr_match(nam, &rp->rc_nam)) {
if ((rp->rc_flag & RC_LOCKED) != 0) {
rp->rc_flag |= RC_WANTED;
(void) tsleep((caddr_t)rp, PZERO-1, "nfsrc", 0);
goto loop;
}
rp->rc_flag |= RC_LOCKED;
put_at_head(rp);
if (rp->rc_state == RC_UNUSED)
panic("nfsrv cache");
if (rp->rc_state == RC_INPROG ||
(time.tv_sec - rp->rc_timestamp) < RC_DELAY) {
nfsstats.srvcache_inproghits++;
ret = RC_DROPIT;
} else if (rp->rc_flag & RC_REPSTATUS) {
nfsstats.srvcache_idemdonehits++;
nfs_rephead(0, xid, rp->rc_status, repp, &mb,
&bpos);
rp->rc_timestamp = time.tv_sec;
ret = RC_REPLY;
} else if (rp->rc_flag & RC_REPMBUF) {
nfsstats.srvcache_idemdonehits++;
*repp = m_copym(rp->rc_reply, 0, M_COPYALL,
M_WAIT);
rp->rc_timestamp = time.tv_sec;
ret = RC_REPLY;
} else {
nfsstats.srvcache_nonidemdonehits++;
rp->rc_state = RC_INPROG;
ret = RC_DOIT;
}
rp->rc_flag &= ~RC_LOCKED;
if (rp->rc_flag & RC_WANTED) {
rp->rc_flag &= ~RC_WANTED;
wakeup((caddr_t)rp);
}
return (ret);
}
}
nfsstats.srvcache_misses++;
rp = nfsrvcachehead.rc_prev;
while ((rp->rc_flag & RC_LOCKED) != 0) {
rp->rc_flag |= RC_WANTED;
(void) tsleep((caddr_t)rp, PZERO-1, "nfsrc", 0);
}
remque(rp);
put_at_head(rp);
if (rp->rc_flag & RC_REPMBUF)
mb = rp->rc_reply;
else
mb = (struct mbuf *)0;
rp->rc_flag = 0;
rp->rc_state = RC_INPROG;
rp->rc_xid = xid;
bcopy((caddr_t)nam, (caddr_t)&rp->rc_nam, sizeof (struct mbuf));
rp->rc_nam.m_data = rp->rc_nam.m_dat; /* for now; hopefully correct? certainly better */
rp->rc_proc = proc;
insque(rp, rh);
if (mb)
m_freem(mb);
return (RC_DOIT);
}
/*
* Update a request cache entry after the rpc has been done
*/
nfsrv_updatecache(nam, xid, proc, repvalid, repstat, repmbuf)
struct mbuf *nam;
u_long xid;
int proc;
int repvalid;
int repstat;
struct mbuf *repmbuf;
{
register struct nfsrvcache *rp;
register union rhead *rh;
rh = &rhead[NFSRCHASH(xid)];
loop:
for (rp = rh->rh_chain[0]; rp != (struct nfsrvcache *)rh; rp = rp->rc_forw) {
if (xid == rp->rc_xid && proc == rp->rc_proc &&
nfs_netaddr_match(nam, &rp->rc_nam)) {
if ((rp->rc_flag & RC_LOCKED) != 0) {
rp->rc_flag |= RC_WANTED;
(void) tsleep((caddr_t)rp, PZERO-1, "nfsrc", 0);
goto loop;
}
rp->rc_flag |= RC_LOCKED;
rp->rc_state = RC_DONE;
/*
* If we have a valid reply update status and save
* the reply for non-idempotent rpc's.
* Otherwise invalidate entry by setting the timestamp
* to nil.
*/
if (repvalid) {
rp->rc_timestamp = time.tv_sec;
if (nonidempotent[proc]) {
if (repliesstatus[proc]) {
rp->rc_status = repstat;
rp->rc_flag |= RC_REPSTATUS;
} else {
rp->rc_reply = m_copym(repmbuf,
0, M_COPYALL, M_WAIT);
rp->rc_flag |= RC_REPMBUF;
}
}
} else {
rp->rc_timestamp = 0;
}
rp->rc_flag &= ~RC_LOCKED;
if (rp->rc_flag & RC_WANTED) {
rp->rc_flag &= ~RC_WANTED;
wakeup((caddr_t)rp);
}
return;
}
}
}