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/slab.h>
  13 #include <linux/in.h>
  14 #include <linux/in6.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 #include <net/ipv6.h>
  22
  23 #define NLMDBG_FACILITY         NLMDBG_HOSTCACHE
  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         (300 * HZ)
  28 #define NLM_HOST_COLLECT        (120 * 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 *, unsigned int, int);
  39 static struct nsm_handle *      nsm_find(const struct sockaddr_in *sin,
  40                                          const char *hostname,
  41                                          unsigned int hostname_len);
  42
  43 static void nlm_clear_port(struct sockaddr *sap)
  44 {
  45         switch (sap->sa_family) {
  46         case AF_INET:
  47                 ((struct sockaddr_in *)sap)->sin_port = 0;
  48                 break;
  49         case AF_INET6:
  50                 ((struct sockaddr_in6 *)sap)->sin6_port = 0;
  51                 break;
  52         }
  53 }
  54
  55 static void nlm_display_address(const struct sockaddr *sap,
  56                                 char *buf, const size_t len)
  57 {
  58         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
  59         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
  60
  61         switch (sap->sa_family) {
  62         case AF_UNSPEC:
  63                 snprintf(buf, len, "unspecified");
  64                 break;
  65         case AF_INET:
  66                 snprintf(buf, len, NIPQUAD_FMT, NIPQUAD(sin->sin_addr.s_addr));
  67                 break;
  68         case AF_INET6:
  69                 if (ipv6_addr_v4mapped(&sin6->sin6_addr))
  70                         snprintf(buf, len, NIPQUAD_FMT,
  71                                  NIPQUAD(sin6->sin6_addr.s6_addr32[3]));
  72                 else
  73                         snprintf(buf, len, NIP6_FMT, NIP6(sin6->sin6_addr));
  74                 break;
  75         default:
  76                 snprintf(buf, len, "unsupported address family");
  77                 break;
  78         }
  79 }
  80
  81 /*
  82  * Common host lookup routine for server & client
  83  */
  84 static struct nlm_host *nlm_lookup_host(int server,
  85                                         const struct sockaddr_in *sin,
  86                                         int proto, u32 version,
  87                                         const char *hostname,
  88                                         unsigned int hostname_len,
  89                                         const struct sockaddr_in *ssin)
  90 {
  91         struct hlist_head *chain;
  92         struct hlist_node *pos;
  93         struct nlm_host *host;
  94         struct nsm_handle *nsm = NULL;
  95         int             hash;
  96
  97         dprintk("lockd: nlm_lookup_host(proto=%d, vers=%u,"
  98                         " my role is %s, hostname=%.*s)\n",
  99                         proto, version, server ? "server" : "client",
 100                         hostname_len, hostname ? hostname : "<none>");
 101
 102         hash = NLM_ADDRHASH(sin->sin_addr.s_addr);
 103
 104         /* Lock hash table */
 105         mutex_lock(&nlm_host_mutex);
 106
 107         if (time_after_eq(jiffies, next_gc))
 108                 nlm_gc_hosts();
 109
 110         /* We may keep several nlm_host objects for a peer, because each
 111          * nlm_host is identified by
 112          * (address, protocol, version, server/client)
 113          * We could probably simplify this a little by putting all those
 114          * different NLM rpc_clients into one single nlm_host object.
 115          * This would allow us to have one nlm_host per address.
 116          */
 117         chain = &nlm_hosts[hash];
 118         hlist_for_each_entry(host, pos, chain, h_hash) {
 119                 if (!nlm_cmp_addr(&host->h_addr, sin))
 120                         continue;
 121
 122                 /* See if we have an NSM handle for this client */
 123                 if (!nsm)
 124                         nsm = host->h_nsmhandle;
 125
 126                 if (host->h_proto != proto)
 127                         continue;
 128                 if (host->h_version != version)
 129                         continue;
 130                 if (host->h_server != server)
 131                         continue;
 132                 if (!nlm_cmp_addr(&host->h_saddr, ssin))
 133                         continue;
 134
 135                 /* Move to head of hash chain. */
 136                 hlist_del(&host->h_hash);
 137                 hlist_add_head(&host->h_hash, chain);
 138
 139                 nlm_get_host(host);
 140                 dprintk("lockd: nlm_lookup_host found host %s (%s)\n",
 141                                 host->h_name, host->h_addrbuf);
 142                 goto out;
 143         }
 144
 145         /*
 146          * The host wasn't in our hash table.  If we don't
 147          * have an NSM handle for it yet, create one.
 148          */
 149         if (nsm)
 150                 atomic_inc(&nsm->sm_count);
 151         else {
 152                 host = NULL;
 153                 nsm = nsm_find(sin, hostname, hostname_len);
 154                 if (!nsm) {
 155                         dprintk("lockd: nlm_lookup_host failed; "
 156                                 "no nsm handle\n");
 157                         goto out;
 158                 }
 159         }
 160
 161         host = kzalloc(sizeof(*host), GFP_KERNEL);
 162         if (!host) {
 163                 nsm_release(nsm);
 164                 dprintk("lockd: nlm_lookup_host failed; no memory\n");
 165                 goto out;
 166         }
 167         host->h_name       = nsm->sm_name;
 168         host->h_addr       = *sin;
 169         nlm_clear_port((struct sockaddr *)&host->h_addr);
 170         host->h_saddr      = *ssin;
 171         host->h_version    = version;
 172         host->h_proto      = proto;
 173         host->h_rpcclnt    = NULL;
 174         mutex_init(&host->h_mutex);
 175         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 176         host->h_expires    = jiffies + NLM_HOST_EXPIRE;
 177         atomic_set(&host->h_count, 1);
 178         init_waitqueue_head(&host->h_gracewait);
 179         init_rwsem(&host->h_rwsem);
 180         host->h_state      = 0;                 /* pseudo NSM state */
 181         host->h_nsmstate   = 0;                 /* real NSM state */
 182         host->h_nsmhandle  = nsm;
 183         host->h_server     = server;
 184         hlist_add_head(&host->h_hash, chain);
 185         INIT_LIST_HEAD(&host->h_lockowners);
 186         spin_lock_init(&host->h_lock);
 187         INIT_LIST_HEAD(&host->h_granted);
 188         INIT_LIST_HEAD(&host->h_reclaim);
 189
 190         nrhosts++;
 191
 192         nlm_display_address((struct sockaddr *)&host->h_addr,
 193                                 host->h_addrbuf, sizeof(host->h_addrbuf));
 194         nlm_display_address((struct sockaddr *)&host->h_saddr,
 195                                 host->h_saddrbuf, sizeof(host->h_saddrbuf));
 196
 197         dprintk("lockd: nlm_lookup_host created host %s\n",
 198                         host->h_name);
 199
 200 out:
 201         mutex_unlock(&nlm_host_mutex);
 202         return host;
 203 }
 204
 205 /*
 206  * Destroy a host
 207  */
 208 static void
 209 nlm_destroy_host(struct nlm_host *host)
 210 {
 211         struct rpc_clnt *clnt;
 212
 213         BUG_ON(!list_empty(&host->h_lockowners));
 214         BUG_ON(atomic_read(&host->h_count));
 215
 216         /*
 217          * Release NSM handle and unmonitor host.
 218          */
 219         nsm_unmonitor(host);
 220
 221         clnt = host->h_rpcclnt;
 222         if (clnt != NULL)
 223                 rpc_shutdown_client(clnt);
 224         kfree(host);
 225 }
 226
 227 /*
 228  * Find an NLM server handle in the cache. If there is none, create it.
 229  */
 230 struct nlm_host *nlmclnt_lookup_host(const struct sockaddr_in *sin,
 231                                      int proto, u32 version,
 232                                      const char *hostname,
 233                                      unsigned int hostname_len)
 234 {
 235         const struct sockaddr_in source = {
 236                 .sin_family     = AF_UNSPEC,
 237         };
 238
 239         return nlm_lookup_host(0, sin, proto, version,
 240                                hostname, hostname_len, &source);
 241 }
 242
 243 /*
 244  * Find an NLM client handle in the cache. If there is none, create it.
 245  */
 246 struct nlm_host *
 247 nlmsvc_lookup_host(struct svc_rqst *rqstp,
 248                         const char *hostname, unsigned int hostname_len)
 249 {
 250         const struct sockaddr_in source = {
 251                 .sin_family     = AF_INET,
 252                 .sin_addr       = rqstp->rq_daddr.addr,
 253         };
 254
 255         return nlm_lookup_host(1, svc_addr_in(rqstp),
 256                                rqstp->rq_prot, rqstp->rq_vers,
 257                                hostname, hostname_len, &source);
 258 }
 259
 260 /*
 261  * Create the NLM RPC client for an NLM peer
 262  */
 263 struct rpc_clnt *
 264 nlm_bind_host(struct nlm_host *host)
 265 {
 266         struct rpc_clnt *clnt;
 267
 268         dprintk("lockd: nlm_bind_host %s (%s), my addr=%s\n",
 269                         host->h_name, host->h_addrbuf, host->h_saddrbuf);
 270
 271         /* Lock host handle */
 272         mutex_lock(&host->h_mutex);
 273
 274         /* If we've already created an RPC client, check whether
 275          * RPC rebind is required
 276          */
 277         if ((clnt = host->h_rpcclnt) != NULL) {
 278                 if (time_after_eq(jiffies, host->h_nextrebind)) {
 279                         rpc_force_rebind(clnt);
 280                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 281                         dprintk("lockd: next rebind in %lu jiffies\n",
 282                                         host->h_nextrebind - jiffies);
 283                 }
 284         } else {
 285                 unsigned long increment = nlmsvc_timeout;
 286                 struct rpc_timeout timeparms = {
 287                         .to_initval     = increment,
 288                         .to_increment   = increment,
 289                         .to_maxval      = increment * 6UL,
 290                         .to_retries     = 5U,
 291                 };
 292                 struct rpc_create_args args = {
 293                         .protocol       = host->h_proto,
 294                         .address        = (struct sockaddr *)&host->h_addr,
 295                         .addrsize       = sizeof(host->h_addr),
 296                         .saddress       = (struct sockaddr *)&host->h_saddr,
 297                         .timeout        = &timeparms,
 298                         .servername     = host->h_name,
 299                         .program        = &nlm_program,
 300                         .version        = host->h_version,
 301                         .authflavor     = RPC_AUTH_UNIX,
 302                         .flags          = (RPC_CLNT_CREATE_NOPING |
 303                                            RPC_CLNT_CREATE_AUTOBIND),
 304                 };
 305
 306                 /*
 307                  * lockd retries server side blocks automatically so we want
 308                  * those to be soft RPC calls. Client side calls need to be
 309                  * hard RPC tasks.
 310                  */
 311                 if (!host->h_server)
 312                         args.flags |= RPC_CLNT_CREATE_HARDRTRY;
 313
 314                 clnt = rpc_create(&args);
 315                 if (!IS_ERR(clnt))
 316                         host->h_rpcclnt = clnt;
 317                 else {
 318                         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
 319                         clnt = NULL;
 320                 }
 321         }
 322
 323         mutex_unlock(&host->h_mutex);
 324         return clnt;
 325 }
 326
 327 /*
 328  * Force a portmap lookup of the remote lockd port
 329  */
 330 void
 331 nlm_rebind_host(struct nlm_host *host)
 332 {
 333         dprintk("lockd: rebind host %s\n", host->h_name);
 334         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
 335                 rpc_force_rebind(host->h_rpcclnt);
 336                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 337         }
 338 }
 339
 340 /*
 341  * Increment NLM host count
 342  */
 343 struct nlm_host * nlm_get_host(struct nlm_host *host)
 344 {
 345         if (host) {
 346                 dprintk("lockd: get host %s\n", host->h_name);
 347                 atomic_inc(&host->h_count);
 348                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
 349         }
 350         return host;
 351 }
 352
 353 /*
 354  * Release NLM host after use
 355  */
 356 void nlm_release_host(struct nlm_host *host)
 357 {
 358         if (host != NULL) {
 359                 dprintk("lockd: release host %s\n", host->h_name);
 360                 BUG_ON(atomic_read(&host->h_count) < 0);
 361                 if (atomic_dec_and_test(&host->h_count)) {
 362                         BUG_ON(!list_empty(&host->h_lockowners));
 363                         BUG_ON(!list_empty(&host->h_granted));
 364                         BUG_ON(!list_empty(&host->h_reclaim));
 365                 }
 366         }
 367 }
 368
 369 /*
 370  * We were notified that the host indicated by address &sin
 371  * has rebooted.
 372  * Release all resources held by that peer.
 373  */
 374 void nlm_host_rebooted(const struct sockaddr_in *sin,
 375                                 const char *hostname,
 376                                 unsigned int hostname_len,
 377                                 u32 new_state)
 378 {
 379         struct hlist_head *chain;
 380         struct hlist_node *pos;
 381         struct nsm_handle *nsm;
 382         struct nlm_host *host;
 383
 384         /* Find the NSM handle for this peer */
 385         nsm = __nsm_find(sin, hostname, hostname_len, 0);
 386         if (nsm == NULL) {
 387                 dprintk("lockd: never saw rebooted peer '%.*s' before\n",
 388                                 hostname_len, hostname);
 389                 return;
 390         }
 391
 392         dprintk("lockd: nlm_host_rebooted(%.*s, %s)\n",
 393                         hostname_len, hostname, nsm->sm_addrbuf);
 394
 395         /* When reclaiming locks on this peer, make sure that
 396          * we set up a new notification */
 397         nsm->sm_monitored = 0;
 398
 399         /* Mark all hosts tied to this NSM state as having rebooted.
 400          * We run the loop repeatedly, because we drop the host table
 401          * lock for this.
 402          * To avoid processing a host several times, we match the nsmstate.
 403          */
 404 again:  mutex_lock(&nlm_host_mutex);
 405         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 406                 hlist_for_each_entry(host, pos, chain, h_hash) {
 407                         if (host->h_nsmhandle == nsm
 408                          && host->h_nsmstate != new_state) {
 409                                 host->h_nsmstate = new_state;
 410                                 host->h_state++;
 411
 412                                 nlm_get_host(host);
 413                                 mutex_unlock(&nlm_host_mutex);
 414
 415                                 if (host->h_server) {
 416                                         /* We're server for this guy, just ditch
 417                                          * all the locks he held. */
 418                                         nlmsvc_free_host_resources(host);
 419                                 } else {
 420                                         /* He's the server, initiate lock recovery. */
 421                                         nlmclnt_recovery(host);
 422                                 }
 423
 424                                 nlm_release_host(host);
 425                                 goto again;
 426                         }
 427                 }
 428         }
 429
 430         mutex_unlock(&nlm_host_mutex);
 431 }
 432
 433 /*
 434  * Shut down the hosts module.
 435  * Note that this routine is called only at server shutdown time.
 436  */
 437 void
 438 nlm_shutdown_hosts(void)
 439 {
 440         struct hlist_head *chain;
 441         struct hlist_node *pos;
 442         struct nlm_host *host;
 443
 444         dprintk("lockd: shutting down host module\n");
 445         mutex_lock(&nlm_host_mutex);
 446
 447         /* First, make all hosts eligible for gc */
 448         dprintk("lockd: nuking all hosts...\n");
 449         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 450                 hlist_for_each_entry(host, pos, chain, h_hash) {
 451                         host->h_expires = jiffies - 1;
 452                         if (host->h_rpcclnt) {
 453                                 rpc_shutdown_client(host->h_rpcclnt);
 454                                 host->h_rpcclnt = NULL;
 455                         }
 456                 }
 457         }
 458
 459         /* Then, perform a garbage collection pass */
 460         nlm_gc_hosts();
 461         mutex_unlock(&nlm_host_mutex);
 462
 463         /* complain if any hosts are left */
 464         if (nrhosts) {
 465                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
 466                 dprintk("lockd: %d hosts left:\n", nrhosts);
 467                 for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 468                         hlist_for_each_entry(host, pos, chain, h_hash) {
 469                                 dprintk("       %s (cnt %d use %d exp %ld)\n",
 470                                         host->h_name, atomic_read(&host->h_count),
 471                                         host->h_inuse, host->h_expires);
 472                         }
 473                 }
 474         }
 475 }
 476
 477 /*
 478  * Garbage collect any unused NLM hosts.
 479  * This GC combines reference counting for async operations with
 480  * mark & sweep for resources held by remote clients.
 481  */
 482 static void
 483 nlm_gc_hosts(void)
 484 {
 485         struct hlist_head *chain;
 486         struct hlist_node *pos, *next;
 487         struct nlm_host *host;
 488
 489         dprintk("lockd: host garbage collection\n");
 490         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 491                 hlist_for_each_entry(host, pos, chain, h_hash)
 492                         host->h_inuse = 0;
 493         }
 494
 495         /* Mark all hosts that hold locks, blocks or shares */
 496         nlmsvc_mark_resources();
 497
 498         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 499                 hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
 500                         if (atomic_read(&host->h_count) || host->h_inuse
 501                          || time_before(jiffies, host->h_expires)) {
 502                                 dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
 503                                         host->h_name, atomic_read(&host->h_count),
 504                                         host->h_inuse, host->h_expires);
 505                                 continue;
 506                         }
 507                         dprintk("lockd: delete host %s\n", host->h_name);
 508                         hlist_del_init(&host->h_hash);
 509
 510                         nlm_destroy_host(host);
 511                         nrhosts--;
 512                 }
 513         }
 514
 515         next_gc = jiffies + NLM_HOST_COLLECT;
 516 }
 517
 518
 519 /*
 520  * Manage NSM handles
 521  */
 522 static LIST_HEAD(nsm_handles);
 523 static DEFINE_SPINLOCK(nsm_lock);
 524
 525 static struct nsm_handle *
 526 __nsm_find(const struct sockaddr_in *sin,
 527                 const char *hostname, unsigned int hostname_len,
 528                 int create)
 529 {
 530         struct nsm_handle *nsm = NULL;
 531         struct nsm_handle *pos;
 532
 533         if (!sin)
 534                 return NULL;
 535
 536         if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
 537                 if (printk_ratelimit()) {
 538                         printk(KERN_WARNING "Invalid hostname \"%.*s\" "
 539                                             "in NFS lock request\n",
 540                                 hostname_len, hostname);
 541                 }
 542                 return NULL;
 543         }
 544
 545 retry:
 546         spin_lock(&nsm_lock);
 547         list_for_each_entry(pos, &nsm_handles, sm_link) {
 548
 549                 if (hostname && nsm_use_hostnames) {
 550                         if (strlen(pos->sm_name) != hostname_len
 551                          || memcmp(pos->sm_name, hostname, hostname_len))
 552                                 continue;
 553                 } else if (!nlm_cmp_addr(&pos->sm_addr, sin))
 554                         continue;
 555                 atomic_inc(&pos->sm_count);
 556                 kfree(nsm);
 557                 nsm = pos;
 558                 goto found;
 559         }
 560         if (nsm) {
 561                 list_add(&nsm->sm_link, &nsm_handles);
 562                 goto found;
 563         }
 564         spin_unlock(&nsm_lock);
 565
 566         if (!create)
 567                 return NULL;
 568
 569         nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL);
 570         if (nsm == NULL)
 571                 return NULL;
 572
 573         nsm->sm_addr = *sin;
 574         nsm->sm_name = (char *) (nsm + 1);
 575         memcpy(nsm->sm_name, hostname, hostname_len);
 576         nsm->sm_name[hostname_len] = '\0';
 577         nlm_display_address((struct sockaddr *)&nsm->sm_addr,
 578                                 nsm->sm_addrbuf, sizeof(nsm->sm_addrbuf));
 579         atomic_set(&nsm->sm_count, 1);
 580         goto retry;
 581
 582 found:
 583         spin_unlock(&nsm_lock);
 584         return nsm;
 585 }
 586
 587 static struct nsm_handle *
 588 nsm_find(const struct sockaddr_in *sin, const char *hostname,
 589          unsigned int hostname_len)
 590 {
 591         return __nsm_find(sin, hostname, hostname_len, 1);
 592 }
 593
 594 /*
 595  * Release an NSM handle
 596  */
 597 void
 598 nsm_release(struct nsm_handle *nsm)
 599 {
 600         if (!nsm)
 601                 return;
 602         if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
 603                 list_del(&nsm->sm_link);
 604                 spin_unlock(&nsm_lock);
 605                 kfree(nsm);
 606         }
 607 }