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346 lines
8.4 KiB
346 lines
8.4 KiB
/*
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* linux/fs/lockd/host.c
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*
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* Management for NLM peer hosts. The nlm_host struct is shared
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* between client and server implementation. The only reason to
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* do so is to reduce code bloat.
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*
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* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
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*/
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#include <linux/types.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/in.h>
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#include <linux/sunrpc/clnt.h>
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#include <linux/sunrpc/svc.h>
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#include <linux/lockd/lockd.h>
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#include <linux/lockd/sm_inter.h>
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#define NLMDBG_FACILITY NLMDBG_HOSTCACHE
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#define NLM_HOST_MAX 64
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#define NLM_HOST_NRHASH 32
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#define NLM_ADDRHASH(addr) (ntohl(addr) & (NLM_HOST_NRHASH-1))
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#define NLM_HOST_REBIND (60 * HZ)
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#define NLM_HOST_EXPIRE ((nrhosts > NLM_HOST_MAX)? 300 * HZ : 120 * HZ)
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#define NLM_HOST_COLLECT ((nrhosts > NLM_HOST_MAX)? 120 * HZ : 60 * HZ)
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#define NLM_HOST_ADDR(sv) (&(sv)->s_nlmclnt->cl_xprt->addr)
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static struct nlm_host * nlm_hosts[NLM_HOST_NRHASH];
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static unsigned long next_gc;
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static int nrhosts;
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static DECLARE_MUTEX(nlm_host_sema);
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static void nlm_gc_hosts(void);
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/*
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* Find an NLM server handle in the cache. If there is none, create it.
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*/
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struct nlm_host *
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nlmclnt_lookup_host(struct sockaddr_in *sin, int proto, int version)
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{
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return nlm_lookup_host(0, sin, proto, version);
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}
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/*
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* Find an NLM client handle in the cache. If there is none, create it.
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*/
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struct nlm_host *
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nlmsvc_lookup_host(struct svc_rqst *rqstp)
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{
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return nlm_lookup_host(1, &rqstp->rq_addr,
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rqstp->rq_prot, rqstp->rq_vers);
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}
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/*
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* Common host lookup routine for server & client
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*/
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struct nlm_host *
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nlm_lookup_host(int server, struct sockaddr_in *sin,
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int proto, int version)
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{
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struct nlm_host *host, **hp;
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u32 addr;
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int hash;
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dprintk("lockd: nlm_lookup_host(%08x, p=%d, v=%d)\n",
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(unsigned)(sin? ntohl(sin->sin_addr.s_addr) : 0), proto, version);
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hash = NLM_ADDRHASH(sin->sin_addr.s_addr);
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/* Lock hash table */
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down(&nlm_host_sema);
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if (time_after_eq(jiffies, next_gc))
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nlm_gc_hosts();
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for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) {
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if (host->h_proto != proto)
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continue;
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if (host->h_version != version)
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continue;
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if (host->h_server != server)
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continue;
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if (nlm_cmp_addr(&host->h_addr, sin)) {
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if (hp != nlm_hosts + hash) {
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*hp = host->h_next;
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host->h_next = nlm_hosts[hash];
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nlm_hosts[hash] = host;
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}
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nlm_get_host(host);
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up(&nlm_host_sema);
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return host;
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}
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}
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/* Ooops, no host found, create it */
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dprintk("lockd: creating host entry\n");
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if (!(host = (struct nlm_host *) kmalloc(sizeof(*host), GFP_KERNEL)))
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goto nohost;
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memset(host, 0, sizeof(*host));
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addr = sin->sin_addr.s_addr;
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sprintf(host->h_name, "%u.%u.%u.%u", NIPQUAD(addr));
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host->h_addr = *sin;
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host->h_addr.sin_port = 0; /* ouch! */
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host->h_version = version;
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host->h_proto = proto;
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host->h_rpcclnt = NULL;
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init_MUTEX(&host->h_sema);
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host->h_nextrebind = jiffies + NLM_HOST_REBIND;
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host->h_expires = jiffies + NLM_HOST_EXPIRE;
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atomic_set(&host->h_count, 1);
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init_waitqueue_head(&host->h_gracewait);
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host->h_state = 0; /* pseudo NSM state */
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host->h_nsmstate = 0; /* real NSM state */
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host->h_server = server;
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host->h_next = nlm_hosts[hash];
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nlm_hosts[hash] = host;
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INIT_LIST_HEAD(&host->h_lockowners);
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spin_lock_init(&host->h_lock);
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if (++nrhosts > NLM_HOST_MAX)
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next_gc = 0;
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nohost:
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up(&nlm_host_sema);
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return host;
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}
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struct nlm_host *
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nlm_find_client(void)
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{
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/* find a nlm_host for a client for which h_killed == 0.
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* and return it
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*/
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int hash;
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down(&nlm_host_sema);
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for (hash = 0 ; hash < NLM_HOST_NRHASH; hash++) {
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struct nlm_host *host, **hp;
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for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) {
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if (host->h_server &&
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host->h_killed == 0) {
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nlm_get_host(host);
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up(&nlm_host_sema);
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return host;
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}
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}
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}
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up(&nlm_host_sema);
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return NULL;
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}
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/*
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* Create the NLM RPC client for an NLM peer
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*/
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struct rpc_clnt *
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nlm_bind_host(struct nlm_host *host)
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{
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struct rpc_clnt *clnt;
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struct rpc_xprt *xprt;
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dprintk("lockd: nlm_bind_host(%08x)\n",
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(unsigned)ntohl(host->h_addr.sin_addr.s_addr));
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/* Lock host handle */
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down(&host->h_sema);
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/* If we've already created an RPC client, check whether
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* RPC rebind is required
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* Note: why keep rebinding if we're on a tcp connection?
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*/
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if ((clnt = host->h_rpcclnt) != NULL) {
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xprt = clnt->cl_xprt;
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if (!xprt->stream && time_after_eq(jiffies, host->h_nextrebind)) {
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clnt->cl_port = 0;
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host->h_nextrebind = jiffies + NLM_HOST_REBIND;
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dprintk("lockd: next rebind in %ld jiffies\n",
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host->h_nextrebind - jiffies);
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}
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} else {
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xprt = xprt_create_proto(host->h_proto, &host->h_addr, NULL);
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if (IS_ERR(xprt))
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goto forgetit;
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xprt_set_timeout(&xprt->timeout, 5, nlmsvc_timeout);
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/* Existing NLM servers accept AUTH_UNIX only */
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clnt = rpc_create_client(xprt, host->h_name, &nlm_program,
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host->h_version, RPC_AUTH_UNIX);
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if (IS_ERR(clnt)) {
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xprt_destroy(xprt);
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goto forgetit;
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}
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clnt->cl_autobind = 1; /* turn on pmap queries */
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xprt->nocong = 1; /* No congestion control for NLM */
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xprt->resvport = 1; /* NLM requires a reserved port */
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host->h_rpcclnt = clnt;
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}
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up(&host->h_sema);
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return clnt;
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forgetit:
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printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
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up(&host->h_sema);
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return NULL;
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}
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/*
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* Force a portmap lookup of the remote lockd port
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*/
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void
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nlm_rebind_host(struct nlm_host *host)
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{
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dprintk("lockd: rebind host %s\n", host->h_name);
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if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
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host->h_rpcclnt->cl_port = 0;
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host->h_nextrebind = jiffies + NLM_HOST_REBIND;
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}
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}
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/*
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* Increment NLM host count
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*/
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struct nlm_host * nlm_get_host(struct nlm_host *host)
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{
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if (host) {
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dprintk("lockd: get host %s\n", host->h_name);
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atomic_inc(&host->h_count);
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host->h_expires = jiffies + NLM_HOST_EXPIRE;
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}
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return host;
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}
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/*
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* Release NLM host after use
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*/
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void nlm_release_host(struct nlm_host *host)
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{
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if (host != NULL) {
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dprintk("lockd: release host %s\n", host->h_name);
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atomic_dec(&host->h_count);
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BUG_ON(atomic_read(&host->h_count) < 0);
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}
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}
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/*
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* Shut down the hosts module.
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* Note that this routine is called only at server shutdown time.
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*/
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void
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nlm_shutdown_hosts(void)
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{
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struct nlm_host *host;
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int i;
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dprintk("lockd: shutting down host module\n");
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down(&nlm_host_sema);
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/* First, make all hosts eligible for gc */
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dprintk("lockd: nuking all hosts...\n");
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for (i = 0; i < NLM_HOST_NRHASH; i++) {
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for (host = nlm_hosts[i]; host; host = host->h_next)
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host->h_expires = jiffies - 1;
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}
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/* Then, perform a garbage collection pass */
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nlm_gc_hosts();
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up(&nlm_host_sema);
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/* complain if any hosts are left */
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if (nrhosts) {
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printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
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dprintk("lockd: %d hosts left:\n", nrhosts);
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for (i = 0; i < NLM_HOST_NRHASH; i++) {
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for (host = nlm_hosts[i]; host; host = host->h_next) {
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dprintk(" %s (cnt %d use %d exp %ld)\n",
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host->h_name, atomic_read(&host->h_count),
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host->h_inuse, host->h_expires);
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}
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}
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}
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}
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/*
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* Garbage collect any unused NLM hosts.
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* This GC combines reference counting for async operations with
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* mark & sweep for resources held by remote clients.
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*/
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static void
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nlm_gc_hosts(void)
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{
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struct nlm_host **q, *host;
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struct rpc_clnt *clnt;
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int i;
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dprintk("lockd: host garbage collection\n");
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for (i = 0; i < NLM_HOST_NRHASH; i++) {
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for (host = nlm_hosts[i]; host; host = host->h_next)
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host->h_inuse = 0;
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}
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/* Mark all hosts that hold locks, blocks or shares */
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nlmsvc_mark_resources();
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for (i = 0; i < NLM_HOST_NRHASH; i++) {
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q = &nlm_hosts[i];
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while ((host = *q) != NULL) {
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if (atomic_read(&host->h_count) || host->h_inuse
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|| time_before(jiffies, host->h_expires)) {
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dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
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host->h_name, atomic_read(&host->h_count),
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host->h_inuse, host->h_expires);
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q = &host->h_next;
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continue;
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}
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dprintk("lockd: delete host %s\n", host->h_name);
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*q = host->h_next;
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/* Don't unmonitor hosts that have been invalidated */
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if (host->h_monitored && !host->h_killed)
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nsm_unmonitor(host);
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if ((clnt = host->h_rpcclnt) != NULL) {
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if (atomic_read(&clnt->cl_users)) {
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printk(KERN_WARNING
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"lockd: active RPC handle\n");
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clnt->cl_dead = 1;
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} else {
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rpc_destroy_client(host->h_rpcclnt);
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}
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}
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BUG_ON(!list_empty(&host->h_lockowners));
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kfree(host);
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nrhosts--;
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}
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}
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next_gc = jiffies + NLM_HOST_COLLECT;
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}
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