err.no Git - linux-2.6/blob - fs/lockd/host.c

   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 #include <linux/mutex.h>
  20
  21
  22 #define NLMDBG_FACILITY         NLMDBG_HOSTCACHE
  23 #define NLM_HOST_MAX            64
  24 #define NLM_HOST_NRHASH         32
  25 #define NLM_ADDRHASH(addr)      (ntohl(addr) & (NLM_HOST_NRHASH-1))
  26 #define NLM_HOST_REBIND         (60 * HZ)
  27 #define NLM_HOST_EXPIRE         ((nrhosts > NLM_HOST_MAX)? 300 * HZ : 120 * HZ)
  28 #define NLM_HOST_COLLECT        ((nrhosts > NLM_HOST_MAX)? 120 * HZ :  60 * HZ)
  29
  30 static struct hlist_head        nlm_hosts[NLM_HOST_NRHASH];
  31 static unsigned long            next_gc;
  32 static int                      nrhosts;
  33 static DEFINE_MUTEX(nlm_host_mutex);
  34
  35
  36 static void                     nlm_gc_hosts(void);
  37 static struct nsm_handle *      __nsm_find(const struct sockaddr_in *,
  38                                         const char *, int, int);
  39
  40 /*
  41  * Find an NLM server handle in the cache. If there is none, create it.
  42  */
  43 struct nlm_host *
  44 nlmclnt_lookup_host(const struct sockaddr_in *sin, int proto, int version,
  45                         const char *hostname, int hostname_len)
  46 {
  47         return nlm_lookup_host(0, sin, proto, version,
  48                                hostname, hostname_len);
  49 }
  50
  51 /*
  52  * Find an NLM client handle in the cache. If there is none, create it.
  53  */
  54 struct nlm_host *
  55 nlmsvc_lookup_host(struct svc_rqst *rqstp,
  56                         const char *hostname, int hostname_len)
  57 {
  58         return nlm_lookup_host(1, &rqstp->rq_addr,
  59                                rqstp->rq_prot, rqstp->rq_vers,
  60                                hostname, hostname_len);
  61 }
  62
  63 /*
  64  * Common host lookup routine for server & client
  65  */
  66 struct nlm_host *
  67 nlm_lookup_host(int server, const struct sockaddr_in *sin,
  68                                         int proto, int version,
  69                                         const char *hostname,
  70                                         int hostname_len)
  71 {
  72         struct hlist_head *chain;
  73         struct hlist_node *pos;
  74         struct nlm_host *host;
  75         struct nsm_handle *nsm = NULL;
  76         int             hash;
  77
  78         dprintk("lockd: nlm_lookup_host(%u.%u.%u.%u, p=%d, v=%d, my role=%s, name=%.*s)\n",
  79                         NIPQUAD(sin->sin_addr.s_addr), proto, version,
  80                         server? "server" : "client",
  81                         hostname_len,
  82                         hostname? hostname : "<none>");
  83
  84
  85         hash = NLM_ADDRHASH(sin->sin_addr.s_addr);
  86
  87         /* Lock hash table */
  88         mutex_lock(&nlm_host_mutex);
  89
  90         if (time_after_eq(jiffies, next_gc))
  91                 nlm_gc_hosts();
  92
  93         /* We may keep several nlm_host objects for a peer, because each
  94          * nlm_host is identified by
  95          * (address, protocol, version, server/client)
  96          * We could probably simplify this a little by putting all those
  97          * different NLM rpc_clients into one single nlm_host object.
  98          * This would allow us to have one nlm_host per address.
  99          */
 100         chain = &nlm_hosts[hash];
 101         hlist_for_each_entry(host, pos, chain, h_hash) {
 102                 if (!nlm_cmp_addr(&host->h_addr, sin))
 103                         continue;
 104
 105                 /* See if we have an NSM handle for this client */
 106                 if (!nsm && (nsm = host->h_nsmhandle) != 0)
 107                         atomic_inc(&nsm->sm_count);
 108
 109                 if (host->h_proto != proto)
 110                         continue;
 111                 if (host->h_version != version)
 112                         continue;
 113                 if (host->h_server != server)
 114                         continue;
 115
 116                 /* Move to head of hash chain. */
 117                 hlist_del(&host->h_hash);
 118                 hlist_add_head(&host->h_hash, chain);
 119
 120                 nlm_get_host(host);
 121                 goto out;
 122         }
 123
 124         host = NULL;
 125
 126         /* Sadly, the host isn't in our hash table yet. See if
 127          * we have an NSM handle for it. If not, create one.
 128          */
 129         if (!nsm && !(nsm = nsm_find(sin, hostname, hostname_len)))
 130                 goto out;
 131
 132         host = kzalloc(sizeof(*host), GFP_KERNEL);
 133         if (!host) {
 134                 nsm_release(nsm);
 135                 goto out;
 136         }
 137         host->h_name       = nsm->sm_name;
 138         host->h_addr       = *sin;
 139         host->h_addr.sin_port = 0;      /* ouch! */
 140         host->h_version    = version;
 141         host->h_proto      = proto;
 142         host->h_rpcclnt    = NULL;
 143         mutex_init(&host->h_mutex);
 144         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 145         host->h_expires    = jiffies + NLM_HOST_EXPIRE;
 146         atomic_set(&host->h_count, 1);
 147         init_waitqueue_head(&host->h_gracewait);
 148         init_rwsem(&host->h_rwsem);
 149         host->h_state      = 0;                 /* pseudo NSM state */
 150         host->h_nsmstate   = 0;                 /* real NSM state */
 151         host->h_nsmhandle  = nsm;
 152         host->h_server     = server;
 153         hlist_add_head(&host->h_hash, chain);
 154         INIT_LIST_HEAD(&host->h_lockowners);
 155         spin_lock_init(&host->h_lock);
 156         INIT_LIST_HEAD(&host->h_granted);
 157         INIT_LIST_HEAD(&host->h_reclaim);
 158
 159         if (++nrhosts > NLM_HOST_MAX)
 160                 next_gc = 0;
 161
 162 out:
 163         mutex_unlock(&nlm_host_mutex);
 164         return host;
 165 }
 166
 167 struct nlm_host *
 168 nlm_find_client(void)
 169 {
 170         struct hlist_head *chain;
 171         struct hlist_node *pos;
 172
 173         /* find a nlm_host for a client for which h_killed == 0.
 174          * and return it
 175          */
 176         mutex_lock(&nlm_host_mutex);
 177         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 178                 struct nlm_host *host;
 179
 180                 hlist_for_each_entry(host, pos, chain, h_hash) {
 181                         if (host->h_server &&
 182                             host->h_killed == 0) {
 183                                 nlm_get_host(host);
 184                                 mutex_unlock(&nlm_host_mutex);
 185                                 return host;
 186                         }
 187                 }
 188         }
 189         mutex_unlock(&nlm_host_mutex);
 190         return NULL;
 191 }
 192
 193
 194 /*
 195  * Create the NLM RPC client for an NLM peer
 196  */
 197 struct rpc_clnt *
 198 nlm_bind_host(struct nlm_host *host)
 199 {
 200         struct rpc_clnt *clnt;
 201
 202         dprintk("lockd: nlm_bind_host(%08x)\n",
 203                         (unsigned)ntohl(host->h_addr.sin_addr.s_addr));
 204
 205         /* Lock host handle */
 206         mutex_lock(&host->h_mutex);
 207
 208         /* If we've already created an RPC client, check whether
 209          * RPC rebind is required
 210          */
 211         if ((clnt = host->h_rpcclnt) != NULL) {
 212                 if (time_after_eq(jiffies, host->h_nextrebind)) {
 213                         rpc_force_rebind(clnt);
 214                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 215                         dprintk("lockd: next rebind in %ld jiffies\n",
 216                                         host->h_nextrebind - jiffies);
 217                 }
 218         } else {
 219                 unsigned long increment = nlmsvc_timeout * HZ;
 220                 struct rpc_timeout timeparms = {
 221                         .to_initval     = increment,
 222                         .to_increment   = increment,
 223                         .to_maxval      = increment * 6UL,
 224                         .to_retries     = 5U,
 225                 };
 226                 struct rpc_create_args args = {
 227                         .protocol       = host->h_proto,
 228                         .address        = (struct sockaddr *)&host->h_addr,
 229                         .addrsize       = sizeof(host->h_addr),
 230                         .timeout        = &timeparms,
 231                         .servername     = host->h_name,
 232                         .program        = &nlm_program,
 233                         .version        = host->h_version,
 234                         .authflavor     = RPC_AUTH_UNIX,
 235                         .flags          = (RPC_CLNT_CREATE_HARDRTRY |
 236                                            RPC_CLNT_CREATE_AUTOBIND),
 237                 };
 238
 239                 clnt = rpc_create(&args);
 240                 if (!IS_ERR(clnt))
 241                         host->h_rpcclnt = clnt;
 242                 else {
 243                         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
 244                         clnt = NULL;
 245                 }
 246         }
 247
 248         mutex_unlock(&host->h_mutex);
 249         return clnt;
 250 }
 251
 252 /*
 253  * Force a portmap lookup of the remote lockd port
 254  */
 255 void
 256 nlm_rebind_host(struct nlm_host *host)
 257 {
 258         dprintk("lockd: rebind host %s\n", host->h_name);
 259         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
 260                 rpc_force_rebind(host->h_rpcclnt);
 261                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 262         }
 263 }
 264
 265 /*
 266  * Increment NLM host count
 267  */
 268 struct nlm_host * nlm_get_host(struct nlm_host *host)
 269 {
 270         if (host) {
 271                 dprintk("lockd: get host %s\n", host->h_name);
 272                 atomic_inc(&host->h_count);
 273                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
 274         }
 275         return host;
 276 }
 277
 278 /*
 279  * Release NLM host after use
 280  */
 281 void nlm_release_host(struct nlm_host *host)
 282 {
 283         if (host != NULL) {
 284                 dprintk("lockd: release host %s\n", host->h_name);
 285                 BUG_ON(atomic_read(&host->h_count) < 0);
 286                 if (atomic_dec_and_test(&host->h_count)) {
 287                         BUG_ON(!list_empty(&host->h_lockowners));
 288                         BUG_ON(!list_empty(&host->h_granted));
 289                         BUG_ON(!list_empty(&host->h_reclaim));
 290                 }
 291         }
 292 }
 293
 294 /*
 295  * We were notified that the host indicated by address &sin
 296  * has rebooted.
 297  * Release all resources held by that peer.
 298  */
 299 void nlm_host_rebooted(const struct sockaddr_in *sin,
 300                                 const char *hostname, int hostname_len,
 301                                 u32 new_state)
 302 {
 303         struct hlist_head *chain;
 304         struct hlist_node *pos;
 305         struct nsm_handle *nsm;
 306         struct nlm_host *host;
 307
 308         dprintk("lockd: nlm_host_rebooted(%s, %u.%u.%u.%u)\n",
 309                         hostname, NIPQUAD(sin->sin_addr));
 310
 311         /* Find the NSM handle for this peer */
 312         if (!(nsm = __nsm_find(sin, hostname, hostname_len, 0)))
 313                 return;
 314
 315         /* When reclaiming locks on this peer, make sure that
 316          * we set up a new notification */
 317         nsm->sm_monitored = 0;
 318
 319         /* Mark all hosts tied to this NSM state as having rebooted.
 320          * We run the loop repeatedly, because we drop the host table
 321          * lock for this.
 322          * To avoid processing a host several times, we match the nsmstate.
 323          */
 324 again:  mutex_lock(&nlm_host_mutex);
 325         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 326                 hlist_for_each_entry(host, pos, chain, h_hash) {
 327                         if (host->h_nsmhandle == nsm
 328                          && host->h_nsmstate != new_state) {
 329                                 host->h_nsmstate = new_state;
 330                                 host->h_state++;
 331
 332                                 nlm_get_host(host);
 333                                 mutex_unlock(&nlm_host_mutex);
 334
 335                                 if (host->h_server) {
 336                                         /* We're server for this guy, just ditch
 337                                          * all the locks he held. */
 338                                         nlmsvc_free_host_resources(host);
 339                                 } else {
 340                                         /* He's the server, initiate lock recovery. */
 341                                         nlmclnt_recovery(host);
 342                                 }
 343
 344                                 nlm_release_host(host);
 345                                 goto again;
 346                         }
 347                 }
 348         }
 349
 350         mutex_unlock(&nlm_host_mutex);
 351 }
 352
 353 /*
 354  * Shut down the hosts module.
 355  * Note that this routine is called only at server shutdown time.
 356  */
 357 void
 358 nlm_shutdown_hosts(void)
 359 {
 360         struct hlist_head *chain;
 361         struct hlist_node *pos;
 362         struct nlm_host *host;
 363
 364         dprintk("lockd: shutting down host module\n");
 365         mutex_lock(&nlm_host_mutex);
 366
 367         /* First, make all hosts eligible for gc */
 368         dprintk("lockd: nuking all hosts...\n");
 369         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 370                 hlist_for_each_entry(host, pos, chain, h_hash)
 371                         host->h_expires = jiffies - 1;
 372         }
 373
 374         /* Then, perform a garbage collection pass */
 375         nlm_gc_hosts();
 376         mutex_unlock(&nlm_host_mutex);
 377
 378         /* complain if any hosts are left */
 379         if (nrhosts) {
 380                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
 381                 dprintk("lockd: %d hosts left:\n", nrhosts);
 382                 for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 383                         hlist_for_each_entry(host, pos, chain, h_hash) {
 384                                 dprintk("       %s (cnt %d use %d exp %ld)\n",
 385                                         host->h_name, atomic_read(&host->h_count),
 386                                         host->h_inuse, host->h_expires);
 387                         }
 388                 }
 389         }
 390 }
 391
 392 /*
 393  * Garbage collect any unused NLM hosts.
 394  * This GC combines reference counting for async operations with
 395  * mark & sweep for resources held by remote clients.
 396  */
 397 static void
 398 nlm_gc_hosts(void)
 399 {
 400         struct hlist_head *chain;
 401         struct hlist_node *pos, *next;
 402         struct nlm_host *host;
 403         struct rpc_clnt *clnt;
 404
 405         dprintk("lockd: host garbage collection\n");
 406         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 407                 hlist_for_each_entry(host, pos, chain, h_hash)
 408                         host->h_inuse = 0;
 409         }
 410
 411         /* Mark all hosts that hold locks, blocks or shares */
 412         nlmsvc_mark_resources();
 413
 414         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 415                 hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
 416                         if (atomic_read(&host->h_count) || host->h_inuse
 417                          || time_before(jiffies, host->h_expires)) {
 418                                 dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
 419                                         host->h_name, atomic_read(&host->h_count),
 420                                         host->h_inuse, host->h_expires);
 421                                 continue;
 422                         }
 423                         dprintk("lockd: delete host %s\n", host->h_name);
 424                         hlist_del_init(&host->h_hash);
 425
 426                         /*
 427                          * Unmonitor unless host was invalidated (i.e. lockd restarted)
 428                          */
 429                         nsm_unmonitor(host);
 430
 431                         if ((clnt = host->h_rpcclnt) != NULL) {
 432                                 if (atomic_read(&clnt->cl_users)) {
 433                                         printk(KERN_WARNING
 434                                                 "lockd: active RPC handle\n");
 435                                         clnt->cl_dead = 1;
 436                                 } else {
 437                                         rpc_destroy_client(host->h_rpcclnt);
 438                                 }
 439                         }
 440                         kfree(host);
 441                         nrhosts--;
 442                 }
 443         }
 444
 445         next_gc = jiffies + NLM_HOST_COLLECT;
 446 }
 447
 448
 449 /*
 450  * Manage NSM handles
 451  */
 452 static LIST_HEAD(nsm_handles);
 453 static DECLARE_MUTEX(nsm_sema);
 454
 455 static struct nsm_handle *
 456 __nsm_find(const struct sockaddr_in *sin,
 457                 const char *hostname, int hostname_len,
 458                 int create)
 459 {
 460         struct nsm_handle *nsm = NULL;
 461         struct list_head *pos;
 462
 463         if (!sin)
 464                 return NULL;
 465
 466         if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
 467                 if (printk_ratelimit()) {
 468                         printk(KERN_WARNING "Invalid hostname \"%.*s\" "
 469                                             "in NFS lock request\n",
 470                                 hostname_len, hostname);
 471                 }
 472                 return NULL;
 473         }
 474
 475         down(&nsm_sema);
 476         list_for_each(pos, &nsm_handles) {
 477                 nsm = list_entry(pos, struct nsm_handle, sm_link);
 478
 479                 if (!nlm_cmp_addr(&nsm->sm_addr, sin))
 480                         continue;
 481                 atomic_inc(&nsm->sm_count);
 482                 goto out;
 483         }
 484
 485         if (!create) {
 486                 nsm = NULL;
 487                 goto out;
 488         }
 489
 490         nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL);
 491         if (nsm != NULL) {
 492                 nsm->sm_addr = *sin;
 493                 nsm->sm_name = (char *) (nsm + 1);
 494                 memcpy(nsm->sm_name, hostname, hostname_len);
 495                 nsm->sm_name[hostname_len] = '\0';
 496                 atomic_set(&nsm->sm_count, 1);
 497
 498                 list_add(&nsm->sm_link, &nsm_handles);
 499         }
 500
 501 out:    up(&nsm_sema);
 502         return nsm;
 503 }
 504
 505 struct nsm_handle *
 506 nsm_find(const struct sockaddr_in *sin, const char *hostname, int hostname_len)
 507 {
 508         return __nsm_find(sin, hostname, hostname_len, 1);
 509 }
 510
 511 /*
 512  * Release an NSM handle
 513  */
 514 void
 515 nsm_release(struct nsm_handle *nsm)
 516 {
 517         if (!nsm)
 518                 return;
 519         if (atomic_dec_and_test(&nsm->sm_count)) {
 520                 down(&nsm_sema);
 521                 if (atomic_read(&nsm->sm_count) == 0) {
 522                         list_del(&nsm->sm_link);
 523                         kfree(nsm);
 524                 }
 525                 up(&nsm_sema);
 526         }
 527 }