4b6a7bddad
This is because calls with M_WAIT (now M_TRYWAIT) may not wait forever when nothing is available for allocation, and may end up returning NULL. Hopefully we now communicate more of the right thing to developers and make it very clear that it's necessary to check whether calls with M_(TRY)WAIT also resulted in a failed allocation. M_TRYWAIT basically means "try harder, block if necessary, but don't necessarily wait forever." The time spent blocking is tunable with the kern.ipc.mbuf_wait sysctl. M_WAIT is now deprecated but still defined for the next little while. * Fix a typo in a comment in mbuf.h * Fix some code that was actually passing the mbuf subsystem's M_WAIT to malloc(). Made it pass M_WAITOK instead. If we were ever to redefine the value of the M_WAIT flag, this could have became a big problem.
353 lines
9.2 KiB
C
353 lines
9.2 KiB
C
/*
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* Copyright (c) 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Rick Macklem at The University of Guelph.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)nfs_srvcache.c 8.3 (Berkeley) 3/30/95
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* $FreeBSD$
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*/
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/*
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* Reference: Chet Juszczak, "Improving the Performance and Correctness
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* of an NFS Server", in Proc. Winter 1989 USENIX Conference,
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* pages 53-63. San Diego, February 1989.
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*/
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#include <sys/param.h>
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#include <sys/malloc.h>
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#include <sys/mount.h>
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#include <sys/systm.h>
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#include <sys/mbuf.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h> /* for dup_sockaddr */
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#include <netinet/in.h>
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#include <nfs/rpcv2.h>
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#include <nfs/nfsproto.h>
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#include <nfs/nfs.h>
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#include <nfs/nfsrvcache.h>
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#ifndef NFS_NOSERVER
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extern struct nfsstats nfsstats;
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extern int nfsv2_procid[NFS_NPROCS];
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static long numnfsrvcache;
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static long desirednfsrvcache = NFSRVCACHESIZ;
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#define NFSRCHASH(xid) \
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(&nfsrvhashtbl[((xid) + ((xid) >> 24)) & nfsrvhash])
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static LIST_HEAD(nfsrvhash, nfsrvcache) *nfsrvhashtbl;
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static TAILQ_HEAD(nfsrvlru, nfsrvcache) nfsrvlruhead;
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static u_long nfsrvhash;
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#define TRUE 1
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#define FALSE 0
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#define NETFAMILY(rp) \
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(((rp)->rc_flag & RC_INETADDR) ? AF_INET : AF_ISO)
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/*
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* Static array that defines which nfs rpc's are nonidempotent
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*/
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static int nonidempotent[NFS_NPROCS] = {
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FALSE,
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FALSE,
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TRUE,
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FALSE,
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FALSE,
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FALSE,
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FALSE,
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TRUE,
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TRUE,
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TRUE,
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TRUE,
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TRUE,
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TRUE,
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TRUE,
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TRUE,
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TRUE,
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FALSE,
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FALSE,
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FALSE,
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FALSE,
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FALSE,
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FALSE,
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FALSE,
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FALSE,
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FALSE,
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FALSE,
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};
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/* True iff the rpc reply is an nfs status ONLY! */
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static int nfsv2_repstat[NFS_NPROCS] = {
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FALSE,
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FALSE,
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FALSE,
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FALSE,
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FALSE,
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FALSE,
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FALSE,
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FALSE,
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FALSE,
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FALSE,
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TRUE,
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TRUE,
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TRUE,
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TRUE,
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FALSE,
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TRUE,
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FALSE,
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FALSE,
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};
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/*
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* Initialize the server request cache list
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*/
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void
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nfsrv_initcache()
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{
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nfsrvhashtbl = hashinit(desirednfsrvcache, M_NFSD, &nfsrvhash);
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TAILQ_INIT(&nfsrvlruhead);
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}
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/*
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* Look for the request in the cache
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* If found then
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* return action and optionally reply
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* else
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* insert it in the cache
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*
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* The rules are as follows:
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* - if in progress, return DROP request
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* - if completed within DELAY of the current time, return DROP it
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* - if completed a longer time ago return REPLY if the reply was cached or
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* return DOIT
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* Update/add new request at end of lru list
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*/
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int
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nfsrv_getcache(nd, slp, repp)
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register struct nfsrv_descript *nd;
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struct nfssvc_sock *slp;
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struct mbuf **repp;
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{
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register struct nfsrvcache *rp;
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struct mbuf *mb;
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struct sockaddr_in *saddr;
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caddr_t bpos;
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int ret;
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/*
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* Don't cache recent requests for reliable transport protocols.
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* (Maybe we should for the case of a reconnect, but..)
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*/
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if (!nd->nd_nam2)
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return (RC_DOIT);
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loop:
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for (rp = NFSRCHASH(nd->nd_retxid)->lh_first; rp != 0;
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rp = rp->rc_hash.le_next) {
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if (nd->nd_retxid == rp->rc_xid && nd->nd_procnum == rp->rc_proc &&
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netaddr_match(NETFAMILY(rp), &rp->rc_haddr, nd->nd_nam)) {
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NFS_DPF(RC, ("H%03x", rp->rc_xid & 0xfff));
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if ((rp->rc_flag & RC_LOCKED) != 0) {
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rp->rc_flag |= RC_WANTED;
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(void) tsleep((caddr_t)rp, PZERO-1, "nfsrc", 0);
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goto loop;
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}
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rp->rc_flag |= RC_LOCKED;
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/* If not at end of LRU chain, move it there */
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if (rp->rc_lru.tqe_next) {
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TAILQ_REMOVE(&nfsrvlruhead, rp, rc_lru);
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TAILQ_INSERT_TAIL(&nfsrvlruhead, rp, rc_lru);
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}
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if (rp->rc_state == RC_UNUSED)
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panic("nfsrv cache");
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if (rp->rc_state == RC_INPROG) {
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nfsstats.srvcache_inproghits++;
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ret = RC_DROPIT;
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} else if (rp->rc_flag & RC_REPSTATUS) {
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nfsstats.srvcache_nonidemdonehits++;
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nfs_rephead(0, nd, slp, rp->rc_status,
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0, (u_quad_t *)0, repp, &mb, &bpos);
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ret = RC_REPLY;
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} else if (rp->rc_flag & RC_REPMBUF) {
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nfsstats.srvcache_nonidemdonehits++;
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*repp = m_copym(rp->rc_reply, 0, M_COPYALL,
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M_TRYWAIT);
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ret = RC_REPLY;
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} else {
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nfsstats.srvcache_idemdonehits++;
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rp->rc_state = RC_INPROG;
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ret = RC_DOIT;
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}
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rp->rc_flag &= ~RC_LOCKED;
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if (rp->rc_flag & RC_WANTED) {
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rp->rc_flag &= ~RC_WANTED;
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wakeup((caddr_t)rp);
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}
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return (ret);
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}
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}
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nfsstats.srvcache_misses++;
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NFS_DPF(RC, ("M%03x", nd->nd_retxid & 0xfff));
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if (numnfsrvcache < desirednfsrvcache) {
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rp = (struct nfsrvcache *)malloc((u_long)sizeof *rp,
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M_NFSD, M_WAITOK | M_ZERO);
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numnfsrvcache++;
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rp->rc_flag = RC_LOCKED;
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} else {
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rp = nfsrvlruhead.tqh_first;
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while ((rp->rc_flag & RC_LOCKED) != 0) {
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rp->rc_flag |= RC_WANTED;
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(void) tsleep((caddr_t)rp, PZERO-1, "nfsrc", 0);
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rp = nfsrvlruhead.tqh_first;
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}
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rp->rc_flag |= RC_LOCKED;
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LIST_REMOVE(rp, rc_hash);
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TAILQ_REMOVE(&nfsrvlruhead, rp, rc_lru);
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if (rp->rc_flag & RC_REPMBUF)
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m_freem(rp->rc_reply);
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if (rp->rc_flag & RC_NAM)
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FREE(rp->rc_nam, M_SONAME);
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rp->rc_flag &= (RC_LOCKED | RC_WANTED);
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}
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TAILQ_INSERT_TAIL(&nfsrvlruhead, rp, rc_lru);
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rp->rc_state = RC_INPROG;
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rp->rc_xid = nd->nd_retxid;
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saddr = (struct sockaddr_in *)nd->nd_nam;
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switch (saddr->sin_family) {
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case AF_INET:
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rp->rc_flag |= RC_INETADDR;
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rp->rc_inetaddr = saddr->sin_addr.s_addr;
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break;
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case AF_ISO:
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default:
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rp->rc_flag |= RC_NAM;
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rp->rc_nam = dup_sockaddr(nd->nd_nam, 1);
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break;
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};
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rp->rc_proc = nd->nd_procnum;
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LIST_INSERT_HEAD(NFSRCHASH(nd->nd_retxid), rp, rc_hash);
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rp->rc_flag &= ~RC_LOCKED;
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if (rp->rc_flag & RC_WANTED) {
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rp->rc_flag &= ~RC_WANTED;
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wakeup((caddr_t)rp);
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}
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return (RC_DOIT);
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}
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/*
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* Update a request cache entry after the rpc has been done
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*/
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void
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nfsrv_updatecache(nd, repvalid, repmbuf)
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register struct nfsrv_descript *nd;
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int repvalid;
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struct mbuf *repmbuf;
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{
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register struct nfsrvcache *rp;
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if (!nd->nd_nam2)
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return;
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loop:
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for (rp = NFSRCHASH(nd->nd_retxid)->lh_first; rp != 0;
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rp = rp->rc_hash.le_next) {
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if (nd->nd_retxid == rp->rc_xid && nd->nd_procnum == rp->rc_proc &&
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netaddr_match(NETFAMILY(rp), &rp->rc_haddr, nd->nd_nam)) {
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NFS_DPF(RC, ("U%03x", rp->rc_xid & 0xfff));
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if ((rp->rc_flag & RC_LOCKED) != 0) {
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rp->rc_flag |= RC_WANTED;
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(void) tsleep((caddr_t)rp, PZERO-1, "nfsrc", 0);
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goto loop;
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}
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rp->rc_flag |= RC_LOCKED;
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if (rp->rc_state == RC_DONE) {
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/*
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* This can occur if the cache is too small.
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* Retransmits of the same request aren't
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* dropped so we may see the operation
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* complete more then once.
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*/
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if (rp->rc_flag & RC_REPMBUF) {
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m_freem(rp->rc_reply);
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rp->rc_flag &= ~RC_REPMBUF;
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}
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}
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rp->rc_state = RC_DONE;
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/*
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* If we have a valid reply update status and save
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* the reply for non-idempotent rpc's.
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*/
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if (repvalid && nonidempotent[nd->nd_procnum]) {
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if ((nd->nd_flag & ND_NFSV3) == 0 &&
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nfsv2_repstat[nfsv2_procid[nd->nd_procnum]]) {
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rp->rc_status = nd->nd_repstat;
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rp->rc_flag |= RC_REPSTATUS;
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} else {
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rp->rc_reply = m_copym(repmbuf,
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0, M_COPYALL, M_TRYWAIT);
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rp->rc_flag |= RC_REPMBUF;
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}
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}
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rp->rc_flag &= ~RC_LOCKED;
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if (rp->rc_flag & RC_WANTED) {
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rp->rc_flag &= ~RC_WANTED;
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wakeup((caddr_t)rp);
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}
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return;
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}
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}
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NFS_DPF(RC, ("L%03x", nd->nd_retxid & 0xfff));
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}
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/*
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* Clean out the cache. Called when the last nfsd terminates.
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*/
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void
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nfsrv_cleancache()
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{
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register struct nfsrvcache *rp, *nextrp;
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for (rp = nfsrvlruhead.tqh_first; rp != 0; rp = nextrp) {
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nextrp = rp->rc_lru.tqe_next;
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LIST_REMOVE(rp, rc_hash);
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TAILQ_REMOVE(&nfsrvlruhead, rp, rc_lru);
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if (rp->rc_flag & RC_REPMBUF)
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m_freem(rp->rc_reply);
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if (rp->rc_flag & RC_NAM)
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free(rp->rc_nam, M_SONAME);
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free(rp, M_NFSD);
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}
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numnfsrvcache = 0;
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}
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#endif /* NFS_NOSERVER */
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