1 /* 2 * linux/fs/lockd/host.c 3 * 4 * Management for NLM peer hosts. The nlm_host struct is shared 5 * between client and server implementation. The only reason to 6 * do so is to reduce code bloat. 7 * 8 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de> 9 */ 10 11 #include <linux/types.h> 12 #include <linux/sched.h> 13 #include <linux/slab.h> 14 #include <linux/in.h> 15 #include <linux/sunrpc/clnt.h> 16 #include <linux/sunrpc/svc.h> 17 #include <linux/lockd/lockd.h> 18 #include <linux/lockd/sm_inter.h> 19 20 21 #define NLMDBG_FACILITY NLMDBG_HOSTCACHE 22 #define NLM_HOST_MAX 64 23 #define NLM_HOST_NRHASH 32 24 #define NLM_ADDRHASH(addr) (ntohl(addr) & (NLM_HOST_NRHASH-1)) 25 #define NLM_HOST_REBIND (60 * HZ) 26 #define NLM_HOST_EXPIRE ((nrhosts > NLM_HOST_MAX)? 300 * HZ : 120 * HZ) 27 #define NLM_HOST_COLLECT ((nrhosts > NLM_HOST_MAX)? 120 * HZ : 60 * HZ) 28 #define NLM_HOST_ADDR(sv) (&(sv)->s_nlmclnt->cl_xprt->addr) 29 30 static struct nlm_host * nlm_hosts[NLM_HOST_NRHASH]; 31 static unsigned long next_gc; 32 static int nrhosts; 33 static DECLARE_MUTEX(nlm_host_sema); 34 35 36 static void nlm_gc_hosts(void); 37 38 /* 39 * Find an NLM server handle in the cache. If there is none, create it. 40 */ 41 struct nlm_host * 42 nlmclnt_lookup_host(struct sockaddr_in *sin, int proto, int version) 43 { 44 return nlm_lookup_host(0, sin, proto, version); 45 } 46 47 /* 48 * Find an NLM client handle in the cache. If there is none, create it. 49 */ 50 struct nlm_host * 51 nlmsvc_lookup_host(struct svc_rqst *rqstp) 52 { 53 return nlm_lookup_host(1, &rqstp->rq_addr, 54 rqstp->rq_prot, rqstp->rq_vers); 55 } 56 57 /* 58 * Common host lookup routine for server & client 59 */ 60 struct nlm_host * 61 nlm_lookup_host(int server, struct sockaddr_in *sin, 62 int proto, int version) 63 { 64 struct nlm_host *host, **hp; 65 u32 addr; 66 int hash; 67 68 dprintk("lockd: nlm_lookup_host(%08x, p=%d, v=%d)\n", 69 (unsigned)(sin? ntohl(sin->sin_addr.s_addr) : 0), proto, version); 70 71 hash = NLM_ADDRHASH(sin->sin_addr.s_addr); 72 73 /* Lock hash table */ 74 down(&nlm_host_sema); 75 76 if (time_after_eq(jiffies, next_gc)) 77 nlm_gc_hosts(); 78 79 for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) { 80 if (host->h_proto != proto) 81 continue; 82 if (host->h_version != version) 83 continue; 84 if (host->h_server != server) 85 continue; 86 87 if (nlm_cmp_addr(&host->h_addr, sin)) { 88 if (hp != nlm_hosts + hash) { 89 *hp = host->h_next; 90 host->h_next = nlm_hosts[hash]; 91 nlm_hosts[hash] = host; 92 } 93 nlm_get_host(host); 94 up(&nlm_host_sema); 95 return host; 96 } 97 } 98 99 /* Ooops, no host found, create it */ 100 dprintk("lockd: creating host entry\n"); 101 102 if (!(host = (struct nlm_host *) kmalloc(sizeof(*host), GFP_KERNEL))) 103 goto nohost; 104 memset(host, 0, sizeof(*host)); 105 106 addr = sin->sin_addr.s_addr; 107 sprintf(host->h_name, "%u.%u.%u.%u", NIPQUAD(addr)); 108 109 host->h_addr = *sin; 110 host->h_addr.sin_port = 0; /* ouch! */ 111 host->h_version = version; 112 host->h_proto = proto; 113 host->h_rpcclnt = NULL; 114 init_MUTEX(&host->h_sema); 115 host->h_nextrebind = jiffies + NLM_HOST_REBIND; 116 host->h_expires = jiffies + NLM_HOST_EXPIRE; 117 atomic_set(&host->h_count, 1); 118 init_waitqueue_head(&host->h_gracewait); 119 host->h_state = 0; /* pseudo NSM state */ 120 host->h_nsmstate = 0; /* real NSM state */ 121 host->h_server = server; 122 host->h_next = nlm_hosts[hash]; 123 nlm_hosts[hash] = host; 124 INIT_LIST_HEAD(&host->h_lockowners); 125 spin_lock_init(&host->h_lock); 126 127 if (++nrhosts > NLM_HOST_MAX) 128 next_gc = 0; 129 130 nohost: 131 up(&nlm_host_sema); 132 return host; 133 } 134 135 struct nlm_host * 136 nlm_find_client(void) 137 { 138 /* find a nlm_host for a client for which h_killed == 0. 139 * and return it 140 */ 141 int hash; 142 down(&nlm_host_sema); 143 for (hash = 0 ; hash < NLM_HOST_NRHASH; hash++) { 144 struct nlm_host *host, **hp; 145 for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) { 146 if (host->h_server && 147 host->h_killed == 0) { 148 nlm_get_host(host); 149 up(&nlm_host_sema); 150 return host; 151 } 152 } 153 } 154 up(&nlm_host_sema); 155 return NULL; 156 } 157 158 159 /* 160 * Create the NLM RPC client for an NLM peer 161 */ 162 struct rpc_clnt * 163 nlm_bind_host(struct nlm_host *host) 164 { 165 struct rpc_clnt *clnt; 166 struct rpc_xprt *xprt; 167 168 dprintk("lockd: nlm_bind_host(%08x)\n", 169 (unsigned)ntohl(host->h_addr.sin_addr.s_addr)); 170 171 /* Lock host handle */ 172 down(&host->h_sema); 173 174 /* If we've already created an RPC client, check whether 175 * RPC rebind is required 176 */ 177 if ((clnt = host->h_rpcclnt) != NULL) { 178 xprt = clnt->cl_xprt; 179 if (time_after_eq(jiffies, host->h_nextrebind)) { 180 clnt->cl_port = 0; 181 host->h_nextrebind = jiffies + NLM_HOST_REBIND; 182 dprintk("lockd: next rebind in %ld jiffies\n", 183 host->h_nextrebind - jiffies); 184 } 185 } else { 186 xprt = xprt_create_proto(host->h_proto, &host->h_addr, NULL); 187 if (IS_ERR(xprt)) 188 goto forgetit; 189 190 xprt_set_timeout(&xprt->timeout, 5, nlmsvc_timeout); 191 xprt->resvport = 1; /* NLM requires a reserved port */ 192 193 /* Existing NLM servers accept AUTH_UNIX only */ 194 clnt = rpc_create_client(xprt, host->h_name, &nlm_program, 195 host->h_version, RPC_AUTH_UNIX); 196 if (IS_ERR(clnt)) 197 goto forgetit; 198 clnt->cl_autobind = 1; /* turn on pmap queries */ 199 200 host->h_rpcclnt = clnt; 201 } 202 203 up(&host->h_sema); 204 return clnt; 205 206 forgetit: 207 printk("lockd: couldn't create RPC handle for %s\n", host->h_name); 208 up(&host->h_sema); 209 return NULL; 210 } 211 212 /* 213 * Force a portmap lookup of the remote lockd port 214 */ 215 void 216 nlm_rebind_host(struct nlm_host *host) 217 { 218 dprintk("lockd: rebind host %s\n", host->h_name); 219 if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) { 220 host->h_rpcclnt->cl_port = 0; 221 host->h_nextrebind = jiffies + NLM_HOST_REBIND; 222 } 223 } 224 225 /* 226 * Increment NLM host count 227 */ 228 struct nlm_host * nlm_get_host(struct nlm_host *host) 229 { 230 if (host) { 231 dprintk("lockd: get host %s\n", host->h_name); 232 atomic_inc(&host->h_count); 233 host->h_expires = jiffies + NLM_HOST_EXPIRE; 234 } 235 return host; 236 } 237 238 /* 239 * Release NLM host after use 240 */ 241 void nlm_release_host(struct nlm_host *host) 242 { 243 if (host != NULL) { 244 dprintk("lockd: release host %s\n", host->h_name); 245 atomic_dec(&host->h_count); 246 BUG_ON(atomic_read(&host->h_count) < 0); 247 } 248 } 249 250 /* 251 * Shut down the hosts module. 252 * Note that this routine is called only at server shutdown time. 253 */ 254 void 255 nlm_shutdown_hosts(void) 256 { 257 struct nlm_host *host; 258 int i; 259 260 dprintk("lockd: shutting down host module\n"); 261 down(&nlm_host_sema); 262 263 /* First, make all hosts eligible for gc */ 264 dprintk("lockd: nuking all hosts...\n"); 265 for (i = 0; i < NLM_HOST_NRHASH; i++) { 266 for (host = nlm_hosts[i]; host; host = host->h_next) 267 host->h_expires = jiffies - 1; 268 } 269 270 /* Then, perform a garbage collection pass */ 271 nlm_gc_hosts(); 272 up(&nlm_host_sema); 273 274 /* complain if any hosts are left */ 275 if (nrhosts) { 276 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n"); 277 dprintk("lockd: %d hosts left:\n", nrhosts); 278 for (i = 0; i < NLM_HOST_NRHASH; i++) { 279 for (host = nlm_hosts[i]; host; host = host->h_next) { 280 dprintk(" %s (cnt %d use %d exp %ld)\n", 281 host->h_name, atomic_read(&host->h_count), 282 host->h_inuse, host->h_expires); 283 } 284 } 285 } 286 } 287 288 /* 289 * Garbage collect any unused NLM hosts. 290 * This GC combines reference counting for async operations with 291 * mark & sweep for resources held by remote clients. 292 */ 293 static void 294 nlm_gc_hosts(void) 295 { 296 struct nlm_host **q, *host; 297 struct rpc_clnt *clnt; 298 int i; 299 300 dprintk("lockd: host garbage collection\n"); 301 for (i = 0; i < NLM_HOST_NRHASH; i++) { 302 for (host = nlm_hosts[i]; host; host = host->h_next) 303 host->h_inuse = 0; 304 } 305 306 /* Mark all hosts that hold locks, blocks or shares */ 307 nlmsvc_mark_resources(); 308 309 for (i = 0; i < NLM_HOST_NRHASH; i++) { 310 q = &nlm_hosts[i]; 311 while ((host = *q) != NULL) { 312 if (atomic_read(&host->h_count) || host->h_inuse 313 || time_before(jiffies, host->h_expires)) { 314 dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n", 315 host->h_name, atomic_read(&host->h_count), 316 host->h_inuse, host->h_expires); 317 q = &host->h_next; 318 continue; 319 } 320 dprintk("lockd: delete host %s\n", host->h_name); 321 *q = host->h_next; 322 /* Don't unmonitor hosts that have been invalidated */ 323 if (host->h_monitored && !host->h_killed) 324 nsm_unmonitor(host); 325 if ((clnt = host->h_rpcclnt) != NULL) { 326 if (atomic_read(&clnt->cl_users)) { 327 printk(KERN_WARNING 328 "lockd: active RPC handle\n"); 329 clnt->cl_dead = 1; 330 } else { 331 rpc_destroy_client(host->h_rpcclnt); 332 } 333 } 334 BUG_ON(!list_empty(&host->h_lockowners)); 335 kfree(host); 336 nrhosts--; 337 } 338 } 339 340 next_gc = jiffies + NLM_HOST_COLLECT; 341 } 342 343