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