/* * 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 hlist_head 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); static struct nsm_handle * __nsm_find(const struct sockaddr_in *, const char *, int, int); /* * Find an NLM server handle in the cache. If there is none, create it. */ struct nlm_host * nlmclnt_lookup_host(const struct sockaddr_in *sin, int proto, int version, const char *hostname, int hostname_len) { return nlm_lookup_host(0, sin, proto, version, hostname, hostname_len); } /* * Find an NLM client handle in the cache. If there is none, create it. */ struct nlm_host * nlmsvc_lookup_host(struct svc_rqst *rqstp, const char *hostname, int hostname_len) { return nlm_lookup_host(1, &rqstp->rq_addr, rqstp->rq_prot, rqstp->rq_vers, hostname, hostname_len); } /* * Common host lookup routine for server & client */ struct nlm_host * nlm_lookup_host(int server, const struct sockaddr_in *sin, int proto, int version, const char *hostname, int hostname_len) { struct hlist_head *chain; struct hlist_node *pos; struct nlm_host *host; struct nsm_handle *nsm = NULL; int hash; dprintk("lockd: nlm_lookup_host(%u.%u.%u.%u, p=%d, v=%d, my role=%s, name=%.*s)\n", NIPQUAD(sin->sin_addr.s_addr), proto, version, server? "server" : "client", hostname_len, hostname? hostname : "<none>"); 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(); /* We may keep several nlm_host objects for a peer, because each * nlm_host is identified by * (address, protocol, version, server/client) * We could probably simplify this a little by putting all those * different NLM rpc_clients into one single nlm_host object. * This would allow us to have one nlm_host per address. */ chain = &nlm_hosts[hash]; hlist_for_each_entry(host, pos, chain, h_hash) { if (!nlm_cmp_addr(&host->h_addr, sin)) continue; /* See if we have an NSM handle for this client */ if (!nsm) nsm = host->h_nsmhandle; if (host->h_proto != proto) continue; if (host->h_version != version) continue; if (host->h_server != server) continue; /* Move to head of hash chain. */ hlist_del(&host->h_hash); hlist_add_head(&host->h_hash, chain); nlm_get_host(host); goto out; } if (nsm) atomic_inc(&nsm->sm_count); host = NULL; /* Sadly, the host isn't in our hash table yet. See if * we have an NSM handle for it. If not, create one. */ if (!nsm && !(nsm = nsm_find(sin, hostname, hostname_len))) goto out; host = kzalloc(sizeof(*host), GFP_KERNEL); if (!host) { nsm_release(nsm); goto out; } host->h_name = nsm->sm_name; 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_nsmhandle = nsm; host->h_server = server; hlist_add_head(&host->h_hash, chain); 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; out: mutex_unlock(&nlm_host_mutex); return host; } /* * Destroy a host */ static void nlm_destroy_host(struct nlm_host *host) { struct rpc_clnt *clnt; BUG_ON(!list_empty(&host->h_lockowners)); BUG_ON(atomic_read(&host->h_count)); /* * Release NSM handle and unmonitor host. */ 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); } /* * 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)); } } } /* * We were notified that the host indicated by address &sin * has rebooted. * Release all resources held by that peer. */ void nlm_host_rebooted(const struct sockaddr_in *sin, const char *hostname, int hostname_len, u32 new_state) { struct hlist_head *chain; struct hlist_node *pos; struct nsm_handle *nsm; struct nlm_host *host; dprintk("lockd: nlm_host_rebooted(%s, %u.%u.%u.%u)\n", hostname, NIPQUAD(sin->sin_addr)); /* Find the NSM handle for this peer */ if (!(nsm = __nsm_find(sin, hostname, hostname_len, 0))) return; /* When reclaiming locks on this peer, make sure that * we set up a new notification */ nsm->sm_monitored = 0; /* Mark all hosts tied to this NSM state as having rebooted. * We run the loop repeatedly, because we drop the host table * lock for this. * To avoid processing a host several times, we match the nsmstate. */ again: mutex_lock(&nlm_host_mutex); for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) { hlist_for_each_entry(host, pos, chain, h_hash) { if (host->h_nsmhandle == nsm && host->h_nsmstate != new_state) { host->h_nsmstate = new_state; host->h_state++; nlm_get_host(host); mutex_unlock(&nlm_host_mutex); if (host->h_server) { /* We're server for this guy, just ditch * all the locks he held. */ nlmsvc_free_host_resources(host); } else { /* He's the server, initiate lock recovery. */ nlmclnt_recovery(host); } nlm_release_host(host); goto again; } } } mutex_unlock(&nlm_host_mutex); } /* * Shut down the hosts module. * Note that this routine is called only at server shutdown time. */ void nlm_shutdown_hosts(void) { struct hlist_head *chain; struct hlist_node *pos; struct nlm_host *host; 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 (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) { hlist_for_each_entry(host, pos, chain, h_hash) 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 (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) { hlist_for_each_entry(host, pos, chain, h_hash) { 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 hlist_head *chain; struct hlist_node *pos, *next; struct nlm_host *host; dprintk("lockd: host garbage collection\n"); for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) { hlist_for_each_entry(host, pos, chain, h_hash) host->h_inuse = 0; } /* Mark all hosts that hold locks, blocks or shares */ nlmsvc_mark_resources(); for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) { hlist_for_each_entry_safe(host, pos, next, chain, h_hash) { 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); continue; } dprintk("lockd: delete host %s\n", host->h_name); hlist_del_init(&host->h_hash); nlm_destroy_host(host); nrhosts--; } } next_gc = jiffies + NLM_HOST_COLLECT; } /* * Manage NSM handles */ static LIST_HEAD(nsm_handles); static DEFINE_MUTEX(nsm_mutex); static struct nsm_handle * __nsm_find(const struct sockaddr_in *sin, const char *hostname, int hostname_len, int create) { struct nsm_handle *nsm = NULL; struct list_head *pos; if (!sin) return NULL; if (hostname && memchr(hostname, '/', hostname_len) != NULL) { if (printk_ratelimit()) { printk(KERN_WARNING "Invalid hostname \"%.*s\" " "in NFS lock request\n", hostname_len, hostname); } return NULL; } mutex_lock(&nsm_mutex); list_for_each(pos, &nsm_handles) { nsm = list_entry(pos, struct nsm_handle, sm_link); if (hostname && nsm_use_hostnames) { if (strlen(nsm->sm_name) != hostname_len || memcmp(nsm->sm_name, hostname, hostname_len)) continue; } else if (!nlm_cmp_addr(&nsm->sm_addr, sin)) continue; atomic_inc(&nsm->sm_count); goto out; } if (!create) { nsm = NULL; goto out; } nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL); if (nsm != NULL) { nsm->sm_addr = *sin; nsm->sm_name = (char *) (nsm + 1); memcpy(nsm->sm_name, hostname, hostname_len); nsm->sm_name[hostname_len] = '\0'; atomic_set(&nsm->sm_count, 1); list_add(&nsm->sm_link, &nsm_handles); } out: mutex_unlock(&nsm_mutex); return nsm; } struct nsm_handle * nsm_find(const struct sockaddr_in *sin, const char *hostname, int hostname_len) { return __nsm_find(sin, hostname, hostname_len, 1); } /* * Release an NSM handle */ void nsm_release(struct nsm_handle *nsm) { if (!nsm) return; if (atomic_dec_and_test(&nsm->sm_count)) { mutex_lock(&nsm_mutex); if (atomic_read(&nsm->sm_count) == 0) { list_del(&nsm->sm_link); kfree(nsm); } mutex_unlock(&nsm_mutex); } }