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   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_HOST_REBIND         (60 * HZ)
  26 #define NLM_HOST_EXPIRE         (300 * HZ)
  27 #define NLM_HOST_COLLECT        (120 * HZ)
  28
  29 static struct hlist_head        nlm_hosts[NLM_HOST_NRHASH];
  30 static unsigned long            next_gc;
  31 static int                      nrhosts;
  32 static DEFINE_MUTEX(nlm_host_mutex);
  33
  34 static void                     nlm_gc_hosts(void);
  35 static struct nsm_handle        *nsm_find(const struct sockaddr *sap,
  36                                                 const size_t salen,
  37                                                 const char *hostname,
  38                                                 const size_t hostname_len,
  39                                                 const int create);
  40 static void                     nsm_release(struct nsm_handle *nsm);
  41
  42 struct nlm_lookup_host_info {
  43         const int               server;         /* search for server|client */
  44         const struct sockaddr   *sap;           /* address to search for */
  45         const size_t            salen;          /* it's length */
  46         const unsigned short    protocol;       /* transport to search for*/
  47         const u32               version;        /* NLM version to search for */
  48         const char              *hostname;      /* remote's hostname */
  49         const size_t            hostname_len;   /* it's length */
  50         const struct sockaddr   *src_sap;       /* our address (optional) */
  51         const size_t            src_len;        /* it's length */
  52         const int               noresvport;     /* use non-priv port */
  53 };
  54
  55 /*
  56  * Hash function must work well on big- and little-endian platforms
  57  */
  58 static unsigned int __nlm_hash32(const __be32 n)
  59 {
  60         unsigned int hash = (__force u32)n ^ ((__force u32)n >> 16);
  61         return hash ^ (hash >> 8);
  62 }
  63
  64 static unsigned int __nlm_hash_addr4(const struct sockaddr *sap)
  65 {
  66         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
  67         return __nlm_hash32(sin->sin_addr.s_addr);
  68 }
  69
  70 static unsigned int __nlm_hash_addr6(const struct sockaddr *sap)
  71 {
  72         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
  73         const struct in6_addr addr = sin6->sin6_addr;
  74         return __nlm_hash32(addr.s6_addr32[0]) ^
  75                __nlm_hash32(addr.s6_addr32[1]) ^
  76                __nlm_hash32(addr.s6_addr32[2]) ^
  77                __nlm_hash32(addr.s6_addr32[3]);
  78 }
  79
  80 static unsigned int nlm_hash_address(const struct sockaddr *sap)
  81 {
  82         unsigned int hash;
  83
  84         switch (sap->sa_family) {
  85         case AF_INET:
  86                 hash = __nlm_hash_addr4(sap);
  87                 break;
  88         case AF_INET6:
  89                 hash = __nlm_hash_addr6(sap);
  90                 break;
  91         default:
  92                 hash = 0;
  93         }
  94         return hash & (NLM_HOST_NRHASH - 1);
  95 }
  96
  97 static void nlm_clear_port(struct sockaddr *sap)
  98 {
  99         switch (sap->sa_family) {
 100         case AF_INET:
 101                 ((struct sockaddr_in *)sap)->sin_port = 0;
 102                 break;
 103         case AF_INET6:
 104                 ((struct sockaddr_in6 *)sap)->sin6_port = 0;
 105                 break;
 106         }
 107 }
 108
 109 static void nlm_display_ipv4_address(const struct sockaddr *sap, char *buf,
 110                                      const size_t len)
 111 {
 112         const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
 113         snprintf(buf, len, "%pI4", &sin->sin_addr.s_addr);
 114 }
 115
 116 static void nlm_display_ipv6_address(const struct sockaddr *sap, char *buf,
 117                                      const size_t len)
 118 {
 119         const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
 120
 121         if (ipv6_addr_v4mapped(&sin6->sin6_addr))
 122                 snprintf(buf, len, "%pI4", &sin6->sin6_addr.s6_addr32[3]);
 123         else if (sin6->sin6_scope_id != 0)
 124                 snprintf(buf, len, "%pI6%%%u", &sin6->sin6_addr,
 125                                 sin6->sin6_scope_id);
 126         else
 127                 snprintf(buf, len, "%pI6", &sin6->sin6_addr);
 128 }
 129
 130 static void nlm_display_address(const struct sockaddr *sap,
 131                                 char *buf, const size_t len)
 132 {
 133         switch (sap->sa_family) {
 134         case AF_INET:
 135                 nlm_display_ipv4_address(sap, buf, len);
 136                 break;
 137         case AF_INET6:
 138                 nlm_display_ipv6_address(sap, buf, len);
 139                 break;
 140         default:
 141                 snprintf(buf, len, "unsupported address family");
 142                 break;
 143         }
 144 }
 145
 146 /*
 147  * Common host lookup routine for server & client
 148  */
 149 static struct nlm_host *nlm_lookup_host(struct nlm_lookup_host_info *ni)
 150 {
 151         struct hlist_head *chain;
 152         struct hlist_node *pos;
 153         struct nlm_host *host;
 154         struct nsm_handle *nsm = NULL;
 155
 156         mutex_lock(&nlm_host_mutex);
 157
 158         if (time_after_eq(jiffies, next_gc))
 159                 nlm_gc_hosts();
 160
 161         /* We may keep several nlm_host objects for a peer, because each
 162          * nlm_host is identified by
 163          * (address, protocol, version, server/client)
 164          * We could probably simplify this a little by putting all those
 165          * different NLM rpc_clients into one single nlm_host object.
 166          * This would allow us to have one nlm_host per address.
 167          */
 168         chain = &nlm_hosts[nlm_hash_address(ni->sap)];
 169         hlist_for_each_entry(host, pos, chain, h_hash) {
 170                 if (!nlm_cmp_addr(nlm_addr(host), ni->sap))
 171                         continue;
 172
 173                 /* See if we have an NSM handle for this client */
 174                 if (!nsm)
 175                         nsm = host->h_nsmhandle;
 176
 177                 if (host->h_proto != ni->protocol)
 178                         continue;
 179                 if (host->h_version != ni->version)
 180                         continue;
 181                 if (host->h_server != ni->server)
 182                         continue;
 183                 if (ni->server &&
 184                     !nlm_cmp_addr(nlm_srcaddr(host), ni->src_sap))
 185                         continue;
 186
 187                 /* Move to head of hash chain. */
 188                 hlist_del(&host->h_hash);
 189                 hlist_add_head(&host->h_hash, chain);
 190
 191                 nlm_get_host(host);
 192                 dprintk("lockd: nlm_lookup_host found host %s (%s)\n",
 193                                 host->h_name, host->h_addrbuf);
 194                 goto out;
 195         }
 196
 197         /*
 198          * The host wasn't in our hash table.  If we don't
 199          * have an NSM handle for it yet, create one.
 200          */
 201         if (nsm)
 202                 atomic_inc(&nsm->sm_count);
 203         else {
 204                 host = NULL;
 205                 nsm = nsm_find(ni->sap, ni->salen,
 206                                 ni->hostname, ni->hostname_len, 1);
 207                 if (!nsm) {
 208                         dprintk("lockd: nlm_lookup_host failed; "
 209                                 "no nsm handle\n");
 210                         goto out;
 211                 }
 212         }
 213
 214         host = kzalloc(sizeof(*host), GFP_KERNEL);
 215         if (!host) {
 216                 nsm_release(nsm);
 217                 dprintk("lockd: nlm_lookup_host failed; no memory\n");
 218                 goto out;
 219         }
 220         host->h_name       = nsm->sm_name;
 221         host->h_addrbuf    = nsm->sm_addrbuf;
 222         memcpy(nlm_addr(host), ni->sap, ni->salen);
 223         host->h_addrlen = ni->salen;
 224         nlm_clear_port(nlm_addr(host));
 225         memcpy(nlm_srcaddr(host), ni->src_sap, ni->src_len);
 226         host->h_version    = ni->version;
 227         host->h_proto      = ni->protocol;
 228         host->h_rpcclnt    = NULL;
 229         mutex_init(&host->h_mutex);
 230         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 231         host->h_expires    = jiffies + NLM_HOST_EXPIRE;
 232         atomic_set(&host->h_count, 1);
 233         init_waitqueue_head(&host->h_gracewait);
 234         init_rwsem(&host->h_rwsem);
 235         host->h_state      = 0;                 /* pseudo NSM state */
 236         host->h_nsmstate   = 0;                 /* real NSM state */
 237         host->h_nsmhandle  = nsm;
 238         host->h_server     = ni->server;
 239         host->h_noresvport = ni->noresvport;
 240         hlist_add_head(&host->h_hash, chain);
 241         INIT_LIST_HEAD(&host->h_lockowners);
 242         spin_lock_init(&host->h_lock);
 243         INIT_LIST_HEAD(&host->h_granted);
 244         INIT_LIST_HEAD(&host->h_reclaim);
 245
 246         nrhosts++;
 247
 248         dprintk("lockd: nlm_lookup_host created host %s\n",
 249                         host->h_name);
 250
 251 out:
 252         mutex_unlock(&nlm_host_mutex);
 253         return host;
 254 }
 255
 256 /*
 257  * Destroy a host
 258  */
 259 static void
 260 nlm_destroy_host(struct nlm_host *host)
 261 {
 262         struct rpc_clnt *clnt;
 263
 264         BUG_ON(!list_empty(&host->h_lockowners));
 265         BUG_ON(atomic_read(&host->h_count));
 266
 267         nsm_unmonitor(host);
 268         nsm_release(host->h_nsmhandle);
 269
 270         clnt = host->h_rpcclnt;
 271         if (clnt != NULL)
 272                 rpc_shutdown_client(clnt);
 273         kfree(host);
 274 }
 275
 276 /**
 277  * nlmclnt_lookup_host - Find an NLM host handle matching a remote server
 278  * @sap: network address of server
 279  * @salen: length of server address
 280  * @protocol: transport protocol to use
 281  * @version: NLM protocol version
 282  * @hostname: '\0'-terminated hostname of server
 283  * @noresvport: 1 if non-privileged port should be used
 284  *
 285  * Returns an nlm_host structure that matches the passed-in
 286  * [server address, transport protocol, NLM version, server hostname].
 287  * If one doesn't already exist in the host cache, a new handle is
 288  * created and returned.
 289  */
 290 struct nlm_host *nlmclnt_lookup_host(const struct sockaddr *sap,
 291                                      const size_t salen,
 292                                      const unsigned short protocol,
 293                                      const u32 version,
 294                                      const char *hostname,
 295                                      int noresvport)
 296 {
 297         const struct sockaddr source = {
 298                 .sa_family      = AF_UNSPEC,
 299         };
 300         struct nlm_lookup_host_info ni = {
 301                 .server         = 0,
 302                 .sap            = sap,
 303                 .salen          = salen,
 304                 .protocol       = protocol,
 305                 .version        = version,
 306                 .hostname       = hostname,
 307                 .hostname_len   = strlen(hostname),
 308                 .src_sap        = &source,
 309                 .src_len        = sizeof(source),
 310                 .noresvport     = noresvport,
 311         };
 312
 313         dprintk("lockd: %s(host='%s', vers=%u, proto=%s)\n", __func__,
 314                         (hostname ? hostname : "<none>"), version,
 315                         (protocol == IPPROTO_UDP ? "udp" : "tcp"));
 316
 317         return nlm_lookup_host(&ni);
 318 }
 319
 320 /**
 321  * nlmsvc_lookup_host - Find an NLM host handle matching a remote client
 322  * @rqstp: incoming NLM request
 323  * @hostname: name of client host
 324  * @hostname_len: length of client hostname
 325  *
 326  * Returns an nlm_host structure that matches the [client address,
 327  * transport protocol, NLM version, client hostname] of the passed-in
 328  * NLM request.  If one doesn't already exist in the host cache, a
 329  * new handle is created and returned.
 330  *
 331  * Before possibly creating a new nlm_host, construct a sockaddr
 332  * for a specific source address in case the local system has
 333  * multiple network addresses.  The family of the address in
 334  * rq_daddr is guaranteed to be the same as the family of the
 335  * address in rq_addr, so it's safe to use the same family for
 336  * the source address.
 337  */
 338 struct nlm_host *nlmsvc_lookup_host(const struct svc_rqst *rqstp,
 339                                     const char *hostname,
 340                                     const size_t hostname_len)
 341 {
 342         struct sockaddr_in sin = {
 343                 .sin_family     = AF_INET,
 344         };
 345         struct sockaddr_in6 sin6 = {
 346                 .sin6_family    = AF_INET6,
 347         };
 348         struct nlm_lookup_host_info ni = {
 349                 .server         = 1,
 350                 .sap            = svc_addr(rqstp),
 351                 .salen          = rqstp->rq_addrlen,
 352                 .protocol       = rqstp->rq_prot,
 353                 .version        = rqstp->rq_vers,
 354                 .hostname       = hostname,
 355                 .hostname_len   = hostname_len,
 356                 .src_len        = rqstp->rq_addrlen,
 357         };
 358
 359         dprintk("lockd: %s(host='%*s', vers=%u, proto=%s)\n", __func__,
 360                         (int)hostname_len, hostname, rqstp->rq_vers,
 361                         (rqstp->rq_prot == IPPROTO_UDP ? "udp" : "tcp"));
 362
 363         switch (ni.sap->sa_family) {
 364         case AF_INET:
 365                 sin.sin_addr.s_addr = rqstp->rq_daddr.addr.s_addr;
 366                 ni.src_sap = (struct sockaddr *)&sin;
 367                 break;
 368         case AF_INET6:
 369                 ipv6_addr_copy(&sin6.sin6_addr, &rqstp->rq_daddr.addr6);
 370                 ni.src_sap = (struct sockaddr *)&sin6;
 371                 break;
 372         default:
 373                 return NULL;
 374         }
 375
 376         return nlm_lookup_host(&ni);
 377 }
 378
 379 /*
 380  * Create the NLM RPC client for an NLM peer
 381  */
 382 struct rpc_clnt *
 383 nlm_bind_host(struct nlm_host *host)
 384 {
 385         struct rpc_clnt *clnt;
 386
 387         dprintk("lockd: nlm_bind_host %s (%s)\n",
 388                         host->h_name, host->h_addrbuf);
 389
 390         /* Lock host handle */
 391         mutex_lock(&host->h_mutex);
 392
 393         /* If we've already created an RPC client, check whether
 394          * RPC rebind is required
 395          */
 396         if ((clnt = host->h_rpcclnt) != NULL) {
 397                 if (time_after_eq(jiffies, host->h_nextrebind)) {
 398                         rpc_force_rebind(clnt);
 399                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 400                         dprintk("lockd: next rebind in %lu jiffies\n",
 401                                         host->h_nextrebind - jiffies);
 402                 }
 403         } else {
 404                 unsigned long increment = nlmsvc_timeout;
 405                 struct rpc_timeout timeparms = {
 406                         .to_initval     = increment,
 407                         .to_increment   = increment,
 408                         .to_maxval      = increment * 6UL,
 409                         .to_retries     = 5U,
 410                 };
 411                 struct rpc_create_args args = {
 412                         .protocol       = host->h_proto,
 413                         .address        = nlm_addr(host),
 414                         .addrsize       = host->h_addrlen,
 415                         .saddress       = nlm_srcaddr(host),
 416                         .timeout        = &timeparms,
 417                         .servername     = host->h_name,
 418                         .program        = &nlm_program,
 419                         .version        = host->h_version,
 420                         .authflavor     = RPC_AUTH_UNIX,
 421                         .flags          = (RPC_CLNT_CREATE_NOPING |
 422                                            RPC_CLNT_CREATE_AUTOBIND),
 423                 };
 424
 425                 /*
 426                  * lockd retries server side blocks automatically so we want
 427                  * those to be soft RPC calls. Client side calls need to be
 428                  * hard RPC tasks.
 429                  */
 430                 if (!host->h_server)
 431                         args.flags |= RPC_CLNT_CREATE_HARDRTRY;
 432                 if (host->h_noresvport)
 433                         args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
 434
 435                 clnt = rpc_create(&args);
 436                 if (!IS_ERR(clnt))
 437                         host->h_rpcclnt = clnt;
 438                 else {
 439                         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
 440                         clnt = NULL;
 441                 }
 442         }
 443
 444         mutex_unlock(&host->h_mutex);
 445         return clnt;
 446 }
 447
 448 /*
 449  * Force a portmap lookup of the remote lockd port
 450  */
 451 void
 452 nlm_rebind_host(struct nlm_host *host)
 453 {
 454         dprintk("lockd: rebind host %s\n", host->h_name);
 455         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
 456                 rpc_force_rebind(host->h_rpcclnt);
 457                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 458         }
 459 }
 460
 461 /*
 462  * Increment NLM host count
 463  */
 464 struct nlm_host * nlm_get_host(struct nlm_host *host)
 465 {
 466         if (host) {
 467                 dprintk("lockd: get host %s\n", host->h_name);
 468                 atomic_inc(&host->h_count);
 469                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
 470         }
 471         return host;
 472 }
 473
 474 /*
 475  * Release NLM host after use
 476  */
 477 void nlm_release_host(struct nlm_host *host)
 478 {
 479         if (host != NULL) {
 480                 dprintk("lockd: release host %s\n", host->h_name);
 481                 BUG_ON(atomic_read(&host->h_count) < 0);
 482                 if (atomic_dec_and_test(&host->h_count)) {
 483                         BUG_ON(!list_empty(&host->h_lockowners));
 484                         BUG_ON(!list_empty(&host->h_granted));
 485                         BUG_ON(!list_empty(&host->h_reclaim));
 486                 }
 487         }
 488 }
 489
 490 /*
 491  * We were notified that the host indicated by address &sin
 492  * has rebooted.
 493  * Release all resources held by that peer.
 494  */
 495 void nlm_host_rebooted(const struct sockaddr_in *sin,
 496                                 const char *hostname,
 497                                 unsigned int hostname_len,
 498                                 u32 new_state)
 499 {
 500         struct hlist_head *chain;
 501         struct hlist_node *pos;
 502         struct nsm_handle *nsm;
 503         struct nlm_host *host;
 504
 505         nsm = nsm_find((struct sockaddr *)sin, sizeof(*sin),
 506                         hostname, hostname_len, 0);
 507         if (nsm == NULL) {
 508                 dprintk("lockd: never saw rebooted peer '%.*s' before\n",
 509                                 hostname_len, hostname);
 510                 return;
 511         }
 512
 513         dprintk("lockd: nlm_host_rebooted(%.*s, %s)\n",
 514                         hostname_len, hostname, nsm->sm_addrbuf);
 515
 516         /* When reclaiming locks on this peer, make sure that
 517          * we set up a new notification */
 518         nsm->sm_monitored = 0;
 519
 520         /* Mark all hosts tied to this NSM state as having rebooted.
 521          * We run the loop repeatedly, because we drop the host table
 522          * lock for this.
 523          * To avoid processing a host several times, we match the nsmstate.
 524          */
 525 again:  mutex_lock(&nlm_host_mutex);
 526         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 527                 hlist_for_each_entry(host, pos, chain, h_hash) {
 528                         if (host->h_nsmhandle == nsm
 529                          && host->h_nsmstate != new_state) {
 530                                 host->h_nsmstate = new_state;
 531                                 host->h_state++;
 532
 533                                 nlm_get_host(host);
 534                                 mutex_unlock(&nlm_host_mutex);
 535
 536                                 if (host->h_server) {
 537                                         /* We're server for this guy, just ditch
 538                                          * all the locks he held. */
 539                                         nlmsvc_free_host_resources(host);
 540                                 } else {
 541                                         /* He's the server, initiate lock recovery. */
 542                                         nlmclnt_recovery(host);
 543                                 }
 544
 545                                 nlm_release_host(host);
 546                                 goto again;
 547                         }
 548                 }
 549         }
 550
 551         mutex_unlock(&nlm_host_mutex);
 552 }
 553
 554 /*
 555  * Shut down the hosts module.
 556  * Note that this routine is called only at server shutdown time.
 557  */
 558 void
 559 nlm_shutdown_hosts(void)
 560 {
 561         struct hlist_head *chain;
 562         struct hlist_node *pos;
 563         struct nlm_host *host;
 564
 565         dprintk("lockd: shutting down host module\n");
 566         mutex_lock(&nlm_host_mutex);
 567
 568         /* First, make all hosts eligible for gc */
 569         dprintk("lockd: nuking all hosts...\n");
 570         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 571                 hlist_for_each_entry(host, pos, chain, h_hash) {
 572                         host->h_expires = jiffies - 1;
 573                         if (host->h_rpcclnt) {
 574                                 rpc_shutdown_client(host->h_rpcclnt);
 575                                 host->h_rpcclnt = NULL;
 576                         }
 577                 }
 578         }
 579
 580         /* Then, perform a garbage collection pass */
 581         nlm_gc_hosts();
 582         mutex_unlock(&nlm_host_mutex);
 583
 584         /* complain if any hosts are left */
 585         if (nrhosts) {
 586                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
 587                 dprintk("lockd: %d hosts left:\n", nrhosts);
 588                 for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 589                         hlist_for_each_entry(host, pos, chain, h_hash) {
 590                                 dprintk("       %s (cnt %d use %d exp %ld)\n",
 591                                         host->h_name, atomic_read(&host->h_count),
 592                                         host->h_inuse, host->h_expires);
 593                         }
 594                 }
 595         }
 596 }
 597
 598 /*
 599  * Garbage collect any unused NLM hosts.
 600  * This GC combines reference counting for async operations with
 601  * mark & sweep for resources held by remote clients.
 602  */
 603 static void
 604 nlm_gc_hosts(void)
 605 {
 606         struct hlist_head *chain;
 607         struct hlist_node *pos, *next;
 608         struct nlm_host *host;
 609
 610         dprintk("lockd: host garbage collection\n");
 611         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 612                 hlist_for_each_entry(host, pos, chain, h_hash)
 613                         host->h_inuse = 0;
 614         }
 615
 616         /* Mark all hosts that hold locks, blocks or shares */
 617         nlmsvc_mark_resources();
 618
 619         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 620                 hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
 621                         if (atomic_read(&host->h_count) || host->h_inuse
 622                          || time_before(jiffies, host->h_expires)) {
 623                                 dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
 624                                         host->h_name, atomic_read(&host->h_count),
 625                                         host->h_inuse, host->h_expires);
 626                                 continue;
 627                         }
 628                         dprintk("lockd: delete host %s\n", host->h_name);
 629                         hlist_del_init(&host->h_hash);
 630
 631                         nlm_destroy_host(host);
 632                         nrhosts--;
 633                 }
 634         }
 635
 636         next_gc = jiffies + NLM_HOST_COLLECT;
 637 }
 638
 639
 640 /*
 641  * Manage NSM handles
 642  */
 643 static LIST_HEAD(nsm_handles);
 644 static DEFINE_SPINLOCK(nsm_lock);
 645
 646 static struct nsm_handle *nsm_find(const struct sockaddr *sap,
 647                                    const size_t salen,
 648                                    const char *hostname,
 649                                    const size_t hostname_len,
 650                                    const int create)
 651 {
 652         struct nsm_handle *nsm = NULL;
 653         struct nsm_handle *pos;
 654
 655         if (!sap)
 656                 return NULL;
 657
 658         if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
 659                 if (printk_ratelimit()) {
 660                         printk(KERN_WARNING "Invalid hostname \"%.*s\" "
 661                                             "in NFS lock request\n",
 662                                 (int)hostname_len, hostname);
 663                 }
 664                 return NULL;
 665         }
 666
 667 retry:
 668         spin_lock(&nsm_lock);
 669         list_for_each_entry(pos, &nsm_handles, sm_link) {
 670
 671                 if (hostname && nsm_use_hostnames) {
 672                         if (strlen(pos->sm_name) != hostname_len
 673                          || memcmp(pos->sm_name, hostname, hostname_len))
 674                                 continue;
 675                 } else if (!nlm_cmp_addr(nsm_addr(pos), sap))
 676                         continue;
 677                 atomic_inc(&pos->sm_count);
 678                 kfree(nsm);
 679                 nsm = pos;
 680                 goto found;
 681         }
 682         if (nsm) {
 683                 list_add(&nsm->sm_link, &nsm_handles);
 684                 goto found;
 685         }
 686         spin_unlock(&nsm_lock);
 687
 688         if (!create)
 689                 return NULL;
 690
 691         nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL);
 692         if (nsm == NULL)
 693                 return NULL;
 694
 695         memcpy(nsm_addr(nsm), sap, salen);
 696         nsm->sm_addrlen = salen;
 697         nsm->sm_name = (char *) (nsm + 1);
 698         memcpy(nsm->sm_name, hostname, hostname_len);
 699         nsm->sm_name[hostname_len] = '\0';
 700         nlm_display_address((struct sockaddr *)&nsm->sm_addr,
 701                                 nsm->sm_addrbuf, sizeof(nsm->sm_addrbuf));
 702         atomic_set(&nsm->sm_count, 1);
 703         goto retry;
 704
 705 found:
 706         spin_unlock(&nsm_lock);
 707         return nsm;
 708 }
 709
 710 /*
 711  * Release an NSM handle
 712  */
 713 static void nsm_release(struct nsm_handle *nsm)
 714 {
 715         if (!nsm)
 716                 return;
 717         if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
 718                 list_del(&nsm->sm_link);
 719                 spin_unlock(&nsm_lock);
 720                 kfree(nsm);
 721         }
 722 }