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