git.oblomov.eu 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/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(nlm_addr_in(host), 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(nlm_srcaddr_in(host), 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         memcpy(nlm_addr(host), sin, sizeof(*sin));
 169         host->h_addrlen = sizeof(*sin);
 170         nlm_clear_port(nlm_addr(host));
 171         memcpy(nlm_srcaddr(host), ssin, sizeof(*ssin));
 172         host->h_version    = version;
 173         host->h_proto      = proto;
 174         host->h_rpcclnt    = NULL;
 175         mutex_init(&host->h_mutex);
 176         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 177         host->h_expires    = jiffies + NLM_HOST_EXPIRE;
 178         atomic_set(&host->h_count, 1);
 179         init_waitqueue_head(&host->h_gracewait);
 180         init_rwsem(&host->h_rwsem);
 181         host->h_state      = 0;                 /* pseudo NSM state */
 182         host->h_nsmstate   = 0;                 /* real NSM state */
 183         host->h_nsmhandle  = nsm;
 184         host->h_server     = server;
 185         hlist_add_head(&host->h_hash, chain);
 186         INIT_LIST_HEAD(&host->h_lockowners);
 187         spin_lock_init(&host->h_lock);
 188         INIT_LIST_HEAD(&host->h_granted);
 189         INIT_LIST_HEAD(&host->h_reclaim);
 190
 191         nrhosts++;
 192
 193         nlm_display_address((struct sockaddr *)&host->h_addr,
 194                                 host->h_addrbuf, sizeof(host->h_addrbuf));
 195         nlm_display_address((struct sockaddr *)&host->h_srcaddr,
 196                                 host->h_srcaddrbuf, sizeof(host->h_srcaddrbuf));
 197
 198         dprintk("lockd: nlm_lookup_host created host %s\n",
 199                         host->h_name);
 200
 201 out:
 202         mutex_unlock(&nlm_host_mutex);
 203         return host;
 204 }
 205
 206 /*
 207  * Destroy a host
 208  */
 209 static void
 210 nlm_destroy_host(struct nlm_host *host)
 211 {
 212         struct rpc_clnt *clnt;
 213
 214         BUG_ON(!list_empty(&host->h_lockowners));
 215         BUG_ON(atomic_read(&host->h_count));
 216
 217         /*
 218          * Release NSM handle and unmonitor host.
 219          */
 220         nsm_unmonitor(host);
 221
 222         clnt = host->h_rpcclnt;
 223         if (clnt != NULL)
 224                 rpc_shutdown_client(clnt);
 225         kfree(host);
 226 }
 227
 228 /*
 229  * Find an NLM server handle in the cache. If there is none, create it.
 230  */
 231 struct nlm_host *nlmclnt_lookup_host(const struct sockaddr_in *sin,
 232                                      int proto, u32 version,
 233                                      const char *hostname,
 234                                      unsigned int hostname_len)
 235 {
 236         const struct sockaddr_in source = {
 237                 .sin_family     = AF_UNSPEC,
 238         };
 239
 240         return nlm_lookup_host(0, sin, proto, version,
 241                                hostname, hostname_len, &source);
 242 }
 243
 244 /*
 245  * Find an NLM client handle in the cache. If there is none, create it.
 246  */
 247 struct nlm_host *
 248 nlmsvc_lookup_host(struct svc_rqst *rqstp,
 249                         const char *hostname, unsigned int hostname_len)
 250 {
 251         const struct sockaddr_in source = {
 252                 .sin_family     = AF_INET,
 253                 .sin_addr       = rqstp->rq_daddr.addr,
 254         };
 255
 256         return nlm_lookup_host(1, svc_addr_in(rqstp),
 257                                rqstp->rq_prot, rqstp->rq_vers,
 258                                hostname, hostname_len, &source);
 259 }
 260
 261 /*
 262  * Create the NLM RPC client for an NLM peer
 263  */
 264 struct rpc_clnt *
 265 nlm_bind_host(struct nlm_host *host)
 266 {
 267         struct rpc_clnt *clnt;
 268
 269         dprintk("lockd: nlm_bind_host %s (%s), my addr=%s\n",
 270                         host->h_name, host->h_addrbuf, host->h_srcaddrbuf);
 271
 272         /* Lock host handle */
 273         mutex_lock(&host->h_mutex);
 274
 275         /* If we've already created an RPC client, check whether
 276          * RPC rebind is required
 277          */
 278         if ((clnt = host->h_rpcclnt) != NULL) {
 279                 if (time_after_eq(jiffies, host->h_nextrebind)) {
 280                         rpc_force_rebind(clnt);
 281                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 282                         dprintk("lockd: next rebind in %lu jiffies\n",
 283                                         host->h_nextrebind - jiffies);
 284                 }
 285         } else {
 286                 unsigned long increment = nlmsvc_timeout;
 287                 struct rpc_timeout timeparms = {
 288                         .to_initval     = increment,
 289                         .to_increment   = increment,
 290                         .to_maxval      = increment * 6UL,
 291                         .to_retries     = 5U,
 292                 };
 293                 struct rpc_create_args args = {
 294                         .protocol       = host->h_proto,
 295                         .address        = nlm_addr(host),
 296                         .addrsize       = host->h_addrlen,
 297                         .saddress       = nlm_srcaddr(host),
 298                         .timeout        = &timeparms,
 299                         .servername     = host->h_name,
 300                         .program        = &nlm_program,
 301                         .version        = host->h_version,
 302                         .authflavor     = RPC_AUTH_UNIX,
 303                         .flags          = (RPC_CLNT_CREATE_NOPING |
 304                                            RPC_CLNT_CREATE_AUTOBIND),
 305                 };
 306
 307                 /*
 308                  * lockd retries server side blocks automatically so we want
 309                  * those to be soft RPC calls. Client side calls need to be
 310                  * hard RPC tasks.
 311                  */
 312                 if (!host->h_server)
 313                         args.flags |= RPC_CLNT_CREATE_HARDRTRY;
 314
 315                 clnt = rpc_create(&args);
 316                 if (!IS_ERR(clnt))
 317                         host->h_rpcclnt = clnt;
 318                 else {
 319                         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
 320                         clnt = NULL;
 321                 }
 322         }
 323
 324         mutex_unlock(&host->h_mutex);
 325         return clnt;
 326 }
 327
 328 /*
 329  * Force a portmap lookup of the remote lockd port
 330  */
 331 void
 332 nlm_rebind_host(struct nlm_host *host)
 333 {
 334         dprintk("lockd: rebind host %s\n", host->h_name);
 335         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
 336                 rpc_force_rebind(host->h_rpcclnt);
 337                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 338         }
 339 }
 340
 341 /*
 342  * Increment NLM host count
 343  */
 344 struct nlm_host * nlm_get_host(struct nlm_host *host)
 345 {
 346         if (host) {
 347                 dprintk("lockd: get host %s\n", host->h_name);
 348                 atomic_inc(&host->h_count);
 349                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
 350         }
 351         return host;
 352 }
 353
 354 /*
 355  * Release NLM host after use
 356  */
 357 void nlm_release_host(struct nlm_host *host)
 358 {
 359         if (host != NULL) {
 360                 dprintk("lockd: release host %s\n", host->h_name);
 361                 BUG_ON(atomic_read(&host->h_count) < 0);
 362                 if (atomic_dec_and_test(&host->h_count)) {
 363                         BUG_ON(!list_empty(&host->h_lockowners));
 364                         BUG_ON(!list_empty(&host->h_granted));
 365                         BUG_ON(!list_empty(&host->h_reclaim));
 366                 }
 367         }
 368 }
 369
 370 /*
 371  * We were notified that the host indicated by address &sin
 372  * has rebooted.
 373  * Release all resources held by that peer.
 374  */
 375 void nlm_host_rebooted(const struct sockaddr_in *sin,
 376                                 const char *hostname,
 377                                 unsigned int hostname_len,
 378                                 u32 new_state)
 379 {
 380         struct hlist_head *chain;
 381         struct hlist_node *pos;
 382         struct nsm_handle *nsm;
 383         struct nlm_host *host;
 384
 385         /* Find the NSM handle for this peer */
 386         nsm = __nsm_find(sin, hostname, hostname_len, 0);
 387         if (nsm == NULL) {
 388                 dprintk("lockd: never saw rebooted peer '%.*s' before\n",
 389                                 hostname_len, hostname);
 390                 return;
 391         }
 392
 393         dprintk("lockd: nlm_host_rebooted(%.*s, %s)\n",
 394                         hostname_len, hostname, nsm->sm_addrbuf);
 395
 396         /* When reclaiming locks on this peer, make sure that
 397          * we set up a new notification */
 398         nsm->sm_monitored = 0;
 399
 400         /* Mark all hosts tied to this NSM state as having rebooted.
 401          * We run the loop repeatedly, because we drop the host table
 402          * lock for this.
 403          * To avoid processing a host several times, we match the nsmstate.
 404          */
 405 again:  mutex_lock(&nlm_host_mutex);
 406         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 407                 hlist_for_each_entry(host, pos, chain, h_hash) {
 408                         if (host->h_nsmhandle == nsm
 409                          && host->h_nsmstate != new_state) {
 410                                 host->h_nsmstate = new_state;
 411                                 host->h_state++;
 412
 413                                 nlm_get_host(host);
 414                                 mutex_unlock(&nlm_host_mutex);
 415
 416                                 if (host->h_server) {
 417                                         /* We're server for this guy, just ditch
 418                                          * all the locks he held. */
 419                                         nlmsvc_free_host_resources(host);
 420                                 } else {
 421                                         /* He's the server, initiate lock recovery. */
 422                                         nlmclnt_recovery(host);
 423                                 }
 424
 425                                 nlm_release_host(host);
 426                                 goto again;
 427                         }
 428                 }
 429         }
 430
 431         mutex_unlock(&nlm_host_mutex);
 432 }
 433
 434 /*
 435  * Shut down the hosts module.
 436  * Note that this routine is called only at server shutdown time.
 437  */
 438 void
 439 nlm_shutdown_hosts(void)
 440 {
 441         struct hlist_head *chain;
 442         struct hlist_node *pos;
 443         struct nlm_host *host;
 444
 445         dprintk("lockd: shutting down host module\n");
 446         mutex_lock(&nlm_host_mutex);
 447
 448         /* First, make all hosts eligible for gc */
 449         dprintk("lockd: nuking all hosts...\n");
 450         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 451                 hlist_for_each_entry(host, pos, chain, h_hash) {
 452                         host->h_expires = jiffies - 1;
 453                         if (host->h_rpcclnt) {
 454                                 rpc_shutdown_client(host->h_rpcclnt);
 455                                 host->h_rpcclnt = NULL;
 456                         }
 457                 }
 458         }
 459
 460         /* Then, perform a garbage collection pass */
 461         nlm_gc_hosts();
 462         mutex_unlock(&nlm_host_mutex);
 463
 464         /* complain if any hosts are left */
 465         if (nrhosts) {
 466                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
 467                 dprintk("lockd: %d hosts left:\n", nrhosts);
 468                 for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 469                         hlist_for_each_entry(host, pos, chain, h_hash) {
 470                                 dprintk("       %s (cnt %d use %d exp %ld)\n",
 471                                         host->h_name, atomic_read(&host->h_count),
 472                                         host->h_inuse, host->h_expires);
 473                         }
 474                 }
 475         }
 476 }
 477
 478 /*
 479  * Garbage collect any unused NLM hosts.
 480  * This GC combines reference counting for async operations with
 481  * mark & sweep for resources held by remote clients.
 482  */
 483 static void
 484 nlm_gc_hosts(void)
 485 {
 486         struct hlist_head *chain;
 487         struct hlist_node *pos, *next;
 488         struct nlm_host *host;
 489
 490         dprintk("lockd: host garbage collection\n");
 491         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 492                 hlist_for_each_entry(host, pos, chain, h_hash)
 493                         host->h_inuse = 0;
 494         }
 495
 496         /* Mark all hosts that hold locks, blocks or shares */
 497         nlmsvc_mark_resources();
 498
 499         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 500                 hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
 501                         if (atomic_read(&host->h_count) || host->h_inuse
 502                          || time_before(jiffies, host->h_expires)) {
 503                                 dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
 504                                         host->h_name, atomic_read(&host->h_count),
 505                                         host->h_inuse, host->h_expires);
 506                                 continue;
 507                         }
 508                         dprintk("lockd: delete host %s\n", host->h_name);
 509                         hlist_del_init(&host->h_hash);
 510
 511                         nlm_destroy_host(host);
 512                         nrhosts--;
 513                 }
 514         }
 515
 516         next_gc = jiffies + NLM_HOST_COLLECT;
 517 }
 518
 519
 520 /*
 521  * Manage NSM handles
 522  */
 523 static LIST_HEAD(nsm_handles);
 524 static DEFINE_SPINLOCK(nsm_lock);
 525
 526 static struct nsm_handle *
 527 __nsm_find(const struct sockaddr_in *sin,
 528                 const char *hostname, unsigned int hostname_len,
 529                 int create)
 530 {
 531         struct nsm_handle *nsm = NULL;
 532         struct nsm_handle *pos;
 533
 534         if (!sin)
 535                 return NULL;
 536
 537         if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
 538                 if (printk_ratelimit()) {
 539                         printk(KERN_WARNING "Invalid hostname \"%.*s\" "
 540                                             "in NFS lock request\n",
 541                                 hostname_len, hostname);
 542                 }
 543                 return NULL;
 544         }
 545
 546 retry:
 547         spin_lock(&nsm_lock);
 548         list_for_each_entry(pos, &nsm_handles, sm_link) {
 549
 550                 if (hostname && nsm_use_hostnames) {
 551                         if (strlen(pos->sm_name) != hostname_len
 552                          || memcmp(pos->sm_name, hostname, hostname_len))
 553                                 continue;
 554                 } else if (!nlm_cmp_addr(nsm_addr_in(pos), sin))
 555                         continue;
 556                 atomic_inc(&pos->sm_count);
 557                 kfree(nsm);
 558                 nsm = pos;
 559                 goto found;
 560         }
 561         if (nsm) {
 562                 list_add(&nsm->sm_link, &nsm_handles);
 563                 goto found;
 564         }
 565         spin_unlock(&nsm_lock);
 566
 567         if (!create)
 568                 return NULL;
 569
 570         nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL);
 571         if (nsm == NULL)
 572                 return NULL;
 573
 574         memcpy(nsm_addr(nsm), sin, sizeof(*sin));
 575         nsm->sm_addrlen = sizeof(*sin);
 576         nsm->sm_name = (char *) (nsm + 1);
 577         memcpy(nsm->sm_name, hostname, hostname_len);
 578         nsm->sm_name[hostname_len] = '\0';
 579         nlm_display_address((struct sockaddr *)&nsm->sm_addr,
 580                                 nsm->sm_addrbuf, sizeof(nsm->sm_addrbuf));
 581         atomic_set(&nsm->sm_count, 1);
 582         goto retry;
 583
 584 found:
 585         spin_unlock(&nsm_lock);
 586         return nsm;
 587 }
 588
 589 static struct nsm_handle *
 590 nsm_find(const struct sockaddr_in *sin, const char *hostname,
 591          unsigned int hostname_len)
 592 {
 593         return __nsm_find(sin, hostname, hostname_len, 1);
 594 }
 595
 596 /*
 597  * Release an NSM handle
 598  */
 599 void
 600 nsm_release(struct nsm_handle *nsm)
 601 {
 602         if (!nsm)
 603                 return;
 604         if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
 605                 list_del(&nsm->sm_link);
 606                 spin_unlock(&nsm_lock);
 607                 kfree(nsm);
 608         }
 609 }