/* * linux/fs/lockd/host.c * * Management for NLM peer hosts. The nlm_host struct is shared * between client and server implementation. The only reason to * do so is to reduce code bloat. * * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de> */ #include <linux/types.h> #include <linux/sched.h> #include <linux/slab.h> #include <linux/in.h> #include <linux/sunrpc/clnt.h> #include <linux/sunrpc/svc.h> #include <linux/lockd/lockd.h> #include <linux/lockd/sm_inter.h> #include <linux/mutex.h> #define NLMDBG_FACILITY NLMDBG_HOSTCACHE #define NLM_HOST_MAX 64 #define NLM_HOST_NRHASH 32 #define NLM_ADDRHASH(addr) (ntohl(addr) & (NLM_HOST_NRHASH-1)) #define NLM_HOST_REBIND (60 * HZ) #define NLM_HOST_EXPIRE ((nrhosts > NLM_HOST_MAX)? 300 * HZ : 120 * HZ) #define NLM_HOST_COLLECT ((nrhosts > NLM_HOST_MAX)? 120 * HZ : 60 * HZ) static struct nlm_host * nlm_hosts[NLM_HOST_NRHASH]; static unsigned long next_gc; static int nrhosts; static DEFINE_MUTEX(nlm_host_mutex); static void nlm_gc_hosts(void); /* * Find an NLM server handle in the cache. If there is none, create it. */ struct nlm_host * nlmclnt_lookup_host(struct sockaddr_in *sin, int proto, int version) { return nlm_lookup_host(0, sin, proto, version); } /* * Find an NLM client handle in the cache. If there is none, create it. */ struct nlm_host * nlmsvc_lookup_host(struct svc_rqst *rqstp) { return nlm_lookup_host(1, &rqstp->rq_addr, rqstp->rq_prot, rqstp->rq_vers); } /* * Common host lookup routine for server & client */ struct nlm_host * nlm_lookup_host(int server, struct sockaddr_in *sin, int proto, int version) { struct nlm_host *host, **hp; u32 addr; int hash; dprintk("lockd: nlm_lookup_host(%08x, p=%d, v=%d)\n", (unsigned)(sin? ntohl(sin->sin_addr.s_addr) : 0), proto, version); hash = NLM_ADDRHASH(sin->sin_addr.s_addr); /* Lock hash table */ mutex_lock(&nlm_host_mutex); if (time_after_eq(jiffies, next_gc)) nlm_gc_hosts(); for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) { if (host->h_proto != proto) continue; if (host->h_version != version) continue; if (host->h_server != server) continue; if (nlm_cmp_addr(&host->h_addr, sin)) { if (hp != nlm_hosts + hash) { *hp = host->h_next; host->h_next = nlm_hosts[hash]; nlm_hosts[hash] = host; } nlm_get_host(host); mutex_unlock(&nlm_host_mutex); return host; } } /* Ooops, no host found, create it */ dprintk("lockd: creating host entry\n"); if (!(host = (struct nlm_host *) kmalloc(sizeof(*host), GFP_KERNEL))) goto nohost; memset(host, 0, sizeof(*host)); addr = sin->sin_addr.s_addr; sprintf(host->h_name, "%u.%u.%u.%u", NIPQUAD(addr)); host->h_addr = *sin; host->h_addr.sin_port = 0; /* ouch! */ host->h_version = version; host->h_proto = proto; host->h_rpcclnt = NULL; mutex_init(&host->h_mutex); host->h_nextrebind = jiffies + NLM_HOST_REBIND; host->h_expires = jiffies + NLM_HOST_EXPIRE; atomic_set(&host->h_count, 1); init_waitqueue_head(&host->h_gracewait); init_rwsem(&host->h_rwsem); host->h_state = 0; /* pseudo NSM state */ host->h_nsmstate = 0; /* real NSM state */ host->h_server = server; host->h_next = nlm_hosts[hash]; nlm_hosts[hash] = host; INIT_LIST_HEAD(&host->h_lockowners); spin_lock_init(&host->h_lock); INIT_LIST_HEAD(&host->h_granted); INIT_LIST_HEAD(&host->h_reclaim); if (++nrhosts > NLM_HOST_MAX) next_gc = 0; nohost: mutex_unlock(&nlm_host_mutex); return host; } struct nlm_host * nlm_find_client(void) { /* find a nlm_host for a client for which h_killed == 0. * and return it */ int hash; mutex_lock(&nlm_host_mutex); for (hash = 0 ; hash < NLM_HOST_NRHASH; hash++) { struct nlm_host *host, **hp; for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) { if (host->h_server && host->h_killed == 0) { nlm_get_host(host); mutex_unlock(&nlm_host_mutex); return host; } } } mutex_unlock(&nlm_host_mutex); return NULL; } /* * Create the NLM RPC client for an NLM peer */ struct rpc_clnt * nlm_bind_host(struct nlm_host *host) { struct rpc_clnt *clnt; dprintk("lockd: nlm_bind_host(%08x)\n", (unsigned)ntohl(host->h_addr.sin_addr.s_addr)); /* Lock host handle */ mutex_lock(&host->h_mutex); /* If we've already created an RPC client, check whether * RPC rebind is required */ if ((clnt = host->h_rpcclnt) != NULL) { if (time_after_eq(jiffies, host->h_nextrebind)) { rpc_force_rebind(clnt); host->h_nextrebind = jiffies + NLM_HOST_REBIND; dprintk("lockd: next rebind in %ld jiffies\n", host->h_nextrebind - jiffies); } } else { unsigned long increment = nlmsvc_timeout * HZ; struct rpc_timeout timeparms = { .to_initval = increment, .to_increment = increment, .to_maxval = increment * 6UL, .to_retries = 5U, }; struct rpc_create_args args = { .protocol = host->h_proto, .address = (struct sockaddr *)&host->h_addr, .addrsize = sizeof(host->h_addr), .timeout = &timeparms, .servername = host->h_name, .program = &nlm_program, .version = host->h_version, .authflavor = RPC_AUTH_UNIX, .flags = (RPC_CLNT_CREATE_HARDRTRY | RPC_CLNT_CREATE_AUTOBIND), }; clnt = rpc_create(&args); if (!IS_ERR(clnt)) host->h_rpcclnt = clnt; else { printk("lockd: couldn't create RPC handle for %s\n", host->h_name); clnt = NULL; } } mutex_unlock(&host->h_mutex); return clnt; } /* * Force a portmap lookup of the remote lockd port */ void nlm_rebind_host(struct nlm_host *host) { dprintk("lockd: rebind host %s\n", host->h_name); if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) { rpc_force_rebind(host->h_rpcclnt); host->h_nextrebind = jiffies + NLM_HOST_REBIND; } } /* * Increment NLM host count */ struct nlm_host * nlm_get_host(struct nlm_host *host) { if (host) { dprintk("lockd: get host %s\n", host->h_name); atomic_inc(&host->h_count); host->h_expires = jiffies + NLM_HOST_EXPIRE; } return host; } /* * Release NLM host after use */ void nlm_release_host(struct nlm_host *host) { if (host != NULL) { dprintk("lockd: release host %s\n", host->h_name); BUG_ON(atomic_read(&host->h_count) < 0); if (atomic_dec_and_test(&host->h_count)) { BUG_ON(!list_empty(&host->h_lockowners)); BUG_ON(!list_empty(&host->h_granted)); BUG_ON(!list_empty(&host->h_reclaim)); } } } /* * Shut down the hosts module. * Note that this routine is called only at server shutdown time. */ void nlm_shutdown_hosts(void) { struct nlm_host *host; int i; dprintk("lockd: shutting down host module\n"); mutex_lock(&nlm_host_mutex); /* First, make all hosts eligible for gc */ dprintk("lockd: nuking all hosts...\n"); for (i = 0; i < NLM_HOST_NRHASH; i++) { for (host = nlm_hosts[i]; host; host = host->h_next) host->h_expires = jiffies - 1; } /* Then, perform a garbage collection pass */ nlm_gc_hosts(); mutex_unlock(&nlm_host_mutex); /* complain if any hosts are left */ if (nrhosts) { printk(KERN_WARNING "lockd: couldn't shutdown host module!\n"); dprintk("lockd: %d hosts left:\n", nrhosts); for (i = 0; i < NLM_HOST_NRHASH; i++) { for (host = nlm_hosts[i]; host; host = host->h_next) { dprintk(" %s (cnt %d use %d exp %ld)\n", host->h_name, atomic_read(&host->h_count), host->h_inuse, host->h_expires); } } } } /* * Garbage collect any unused NLM hosts. * This GC combines reference counting for async operations with * mark & sweep for resources held by remote clients. */ static void nlm_gc_hosts(void) { struct nlm_host **q, *host; struct rpc_clnt *clnt; int i; dprintk("lockd: host garbage collection\n"); for (i = 0; i < NLM_HOST_NRHASH; i++) { for (host = nlm_hosts[i]; host; host = host->h_next) host->h_inuse = 0; } /* Mark all hosts that hold locks, blocks or shares */ nlmsvc_mark_resources(); for (i = 0; i < NLM_HOST_NRHASH; i++) { q = &nlm_hosts[i]; while ((host = *q) != NULL) { if (atomic_read(&host->h_count) || host->h_inuse || time_before(jiffies, host->h_expires)) { dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n", host->h_name, atomic_read(&host->h_count), host->h_inuse, host->h_expires); q = &host->h_next; continue; } dprintk("lockd: delete host %s\n", host->h_name); *q = host->h_next; /* Don't unmonitor hosts that have been invalidated */ if (host->h_monitored && !host->h_killed) nsm_unmonitor(host); if ((clnt = host->h_rpcclnt) != NULL) { if (atomic_read(&clnt->cl_users)) { printk(KERN_WARNING "lockd: active RPC handle\n"); clnt->cl_dead = 1; } else { rpc_destroy_client(host->h_rpcclnt); } } kfree(host); nrhosts--; } } next_gc = jiffies + NLM_HOST_COLLECT; }