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/sunrpc/clnt.h>
  15 #include <linux/sunrpc/svc.h>
  16 #include <linux/lockd/lockd.h>
  17 #include <linux/lockd/sm_inter.h>
  18 #include <linux/mutex.h>
  19
  20
  21 #define NLMDBG_FACILITY         NLMDBG_HOSTCACHE
  22 #define NLM_HOST_NRHASH         32
  23 #define NLM_ADDRHASH(addr)      (ntohl(addr) & (NLM_HOST_NRHASH-1))
  24 #define NLM_HOST_REBIND         (60 * HZ)
  25 #define NLM_HOST_EXPIRE         (300 * HZ)
  26 #define NLM_HOST_COLLECT        (120 * HZ)
  27
  28 static struct hlist_head        nlm_hosts[NLM_HOST_NRHASH];
  29 static unsigned long            next_gc;
  30 static int                      nrhosts;
  31 static DEFINE_MUTEX(nlm_host_mutex);
  32
  33
  34 static void                     nlm_gc_hosts(void);
  35 static struct nsm_handle *      __nsm_find(const struct sockaddr_in *,
  36                                         const char *, unsigned int, int);
  37 static struct nsm_handle *      nsm_find(const struct sockaddr_in *sin,
  38                                          const char *hostname,
  39                                          unsigned int hostname_len);
  40
  41 /*
  42  * Common host lookup routine for server & client
  43  */
  44 static struct nlm_host *
  45 nlm_lookup_host(int server, const struct sockaddr_in *sin,
  46                 int proto, int version, const char *hostname,
  47                 unsigned int hostname_len,
  48                 const struct sockaddr_in *ssin)
  49 {
  50         struct hlist_head *chain;
  51         struct hlist_node *pos;
  52         struct nlm_host *host;
  53         struct nsm_handle *nsm = NULL;
  54         int             hash;
  55
  56         dprintk("lockd: nlm_lookup_host("NIPQUAD_FMT"->"NIPQUAD_FMT
  57                         ", p=%d, v=%d, my role=%s, name=%.*s)\n",
  58                         NIPQUAD(ssin->sin_addr.s_addr),
  59                         NIPQUAD(sin->sin_addr.s_addr), proto, version,
  60                         server? "server" : "client",
  61                         hostname_len,
  62                         hostname? hostname : "<none>");
  63
  64
  65         hash = NLM_ADDRHASH(sin->sin_addr.s_addr);
  66
  67         /* Lock hash table */
  68         mutex_lock(&nlm_host_mutex);
  69
  70         if (time_after_eq(jiffies, next_gc))
  71                 nlm_gc_hosts();
  72
  73         /* We may keep several nlm_host objects for a peer, because each
  74          * nlm_host is identified by
  75          * (address, protocol, version, server/client)
  76          * We could probably simplify this a little by putting all those
  77          * different NLM rpc_clients into one single nlm_host object.
  78          * This would allow us to have one nlm_host per address.
  79          */
  80         chain = &nlm_hosts[hash];
  81         hlist_for_each_entry(host, pos, chain, h_hash) {
  82                 if (!nlm_cmp_addr(&host->h_addr, sin))
  83                         continue;
  84
  85                 /* See if we have an NSM handle for this client */
  86                 if (!nsm)
  87                         nsm = host->h_nsmhandle;
  88
  89                 if (host->h_proto != proto)
  90                         continue;
  91                 if (host->h_version != version)
  92                         continue;
  93                 if (host->h_server != server)
  94                         continue;
  95                 if (!nlm_cmp_addr(&host->h_saddr, ssin))
  96                         continue;
  97
  98                 /* Move to head of hash chain. */
  99                 hlist_del(&host->h_hash);
 100                 hlist_add_head(&host->h_hash, chain);
 101
 102                 nlm_get_host(host);
 103                 goto out;
 104         }
 105         if (nsm)
 106                 atomic_inc(&nsm->sm_count);
 107
 108         host = NULL;
 109
 110         /* Sadly, the host isn't in our hash table yet. See if
 111          * we have an NSM handle for it. If not, create one.
 112          */
 113         if (!nsm && !(nsm = nsm_find(sin, hostname, hostname_len)))
 114                 goto out;
 115
 116         host = kzalloc(sizeof(*host), GFP_KERNEL);
 117         if (!host) {
 118                 nsm_release(nsm);
 119                 goto out;
 120         }
 121         host->h_name       = nsm->sm_name;
 122         host->h_addr       = *sin;
 123         host->h_addr.sin_port = 0;      /* ouch! */
 124         host->h_saddr      = *ssin;
 125         host->h_version    = version;
 126         host->h_proto      = proto;
 127         host->h_rpcclnt    = NULL;
 128         mutex_init(&host->h_mutex);
 129         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 130         host->h_expires    = jiffies + NLM_HOST_EXPIRE;
 131         atomic_set(&host->h_count, 1);
 132         init_waitqueue_head(&host->h_gracewait);
 133         init_rwsem(&host->h_rwsem);
 134         host->h_state      = 0;                 /* pseudo NSM state */
 135         host->h_nsmstate   = 0;                 /* real NSM state */
 136         host->h_nsmhandle  = nsm;
 137         host->h_server     = server;
 138         hlist_add_head(&host->h_hash, chain);
 139         INIT_LIST_HEAD(&host->h_lockowners);
 140         spin_lock_init(&host->h_lock);
 141         INIT_LIST_HEAD(&host->h_granted);
 142         INIT_LIST_HEAD(&host->h_reclaim);
 143
 144         nrhosts++;
 145 out:
 146         mutex_unlock(&nlm_host_mutex);
 147         return host;
 148 }
 149
 150 /*
 151  * Destroy a host
 152  */
 153 static void
 154 nlm_destroy_host(struct nlm_host *host)
 155 {
 156         struct rpc_clnt *clnt;
 157
 158         BUG_ON(!list_empty(&host->h_lockowners));
 159         BUG_ON(atomic_read(&host->h_count));
 160
 161         /*
 162          * Release NSM handle and unmonitor host.
 163          */
 164         nsm_unmonitor(host);
 165
 166         clnt = host->h_rpcclnt;
 167         if (clnt != NULL)
 168                 rpc_shutdown_client(clnt);
 169         kfree(host);
 170 }
 171
 172 /*
 173  * Find an NLM server handle in the cache. If there is none, create it.
 174  */
 175 struct nlm_host *
 176 nlmclnt_lookup_host(const struct sockaddr_in *sin, int proto, int version,
 177                         const char *hostname, unsigned int hostname_len)
 178 {
 179         struct sockaddr_in ssin = {0};
 180
 181         return nlm_lookup_host(0, sin, proto, version,
 182                                hostname, hostname_len, &ssin);
 183 }
 184
 185 /*
 186  * Find an NLM client handle in the cache. If there is none, create it.
 187  */
 188 struct nlm_host *
 189 nlmsvc_lookup_host(struct svc_rqst *rqstp,
 190                         const char *hostname, unsigned int hostname_len)
 191 {
 192         struct sockaddr_in ssin = {0};
 193
 194         ssin.sin_addr = rqstp->rq_daddr.addr;
 195         return nlm_lookup_host(1, svc_addr_in(rqstp),
 196                                rqstp->rq_prot, rqstp->rq_vers,
 197                                hostname, hostname_len, &ssin);
 198 }
 199
 200 /*
 201  * Create the NLM RPC client for an NLM peer
 202  */
 203 struct rpc_clnt *
 204 nlm_bind_host(struct nlm_host *host)
 205 {
 206         struct rpc_clnt *clnt;
 207
 208         dprintk("lockd: nlm_bind_host("NIPQUAD_FMT"->"NIPQUAD_FMT")\n",
 209                         NIPQUAD(host->h_saddr.sin_addr),
 210                         NIPQUAD(host->h_addr.sin_addr));
 211
 212         /* Lock host handle */
 213         mutex_lock(&host->h_mutex);
 214
 215         /* If we've already created an RPC client, check whether
 216          * RPC rebind is required
 217          */
 218         if ((clnt = host->h_rpcclnt) != NULL) {
 219                 if (time_after_eq(jiffies, host->h_nextrebind)) {
 220                         rpc_force_rebind(clnt);
 221                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 222                         dprintk("lockd: next rebind in %ld jiffies\n",
 223                                         host->h_nextrebind - jiffies);
 224                 }
 225         } else {
 226                 unsigned long increment = nlmsvc_timeout;
 227                 struct rpc_timeout timeparms = {
 228                         .to_initval     = increment,
 229                         .to_increment   = increment,
 230                         .to_maxval      = increment * 6UL,
 231                         .to_retries     = 5U,
 232                 };
 233                 struct rpc_create_args args = {
 234                         .protocol       = host->h_proto,
 235                         .address        = (struct sockaddr *)&host->h_addr,
 236                         .addrsize       = sizeof(host->h_addr),
 237                         .saddress       = (struct sockaddr *)&host->h_saddr,
 238                         .timeout        = &timeparms,
 239                         .servername     = host->h_name,
 240                         .program        = &nlm_program,
 241                         .version        = host->h_version,
 242                         .authflavor     = RPC_AUTH_UNIX,
 243                         .flags          = (RPC_CLNT_CREATE_NOPING |
 244                                            RPC_CLNT_CREATE_AUTOBIND),
 245                 };
 246
 247                 /*
 248                  * lockd retries server side blocks automatically so we want
 249                  * those to be soft RPC calls. Client side calls need to be
 250                  * hard RPC tasks.
 251                  */
 252                 if (!host->h_server)
 253                         args.flags |= RPC_CLNT_CREATE_HARDRTRY;
 254
 255                 clnt = rpc_create(&args);
 256                 if (!IS_ERR(clnt))
 257                         host->h_rpcclnt = clnt;
 258                 else {
 259                         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
 260                         clnt = NULL;
 261                 }
 262         }
 263
 264         mutex_unlock(&host->h_mutex);
 265         return clnt;
 266 }
 267
 268 /*
 269  * Force a portmap lookup of the remote lockd port
 270  */
 271 void
 272 nlm_rebind_host(struct nlm_host *host)
 273 {
 274         dprintk("lockd: rebind host %s\n", host->h_name);
 275         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
 276                 rpc_force_rebind(host->h_rpcclnt);
 277                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 278         }
 279 }
 280
 281 /*
 282  * Increment NLM host count
 283  */
 284 struct nlm_host * nlm_get_host(struct nlm_host *host)
 285 {
 286         if (host) {
 287                 dprintk("lockd: get host %s\n", host->h_name);
 288                 atomic_inc(&host->h_count);
 289                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
 290         }
 291         return host;
 292 }
 293
 294 /*
 295  * Release NLM host after use
 296  */
 297 void nlm_release_host(struct nlm_host *host)
 298 {
 299         if (host != NULL) {
 300                 dprintk("lockd: release host %s\n", host->h_name);
 301                 BUG_ON(atomic_read(&host->h_count) < 0);
 302                 if (atomic_dec_and_test(&host->h_count)) {
 303                         BUG_ON(!list_empty(&host->h_lockowners));
 304                         BUG_ON(!list_empty(&host->h_granted));
 305                         BUG_ON(!list_empty(&host->h_reclaim));
 306                 }
 307         }
 308 }
 309
 310 /*
 311  * We were notified that the host indicated by address &sin
 312  * has rebooted.
 313  * Release all resources held by that peer.
 314  */
 315 void nlm_host_rebooted(const struct sockaddr_in *sin,
 316                                 const char *hostname,
 317                                 unsigned int hostname_len,
 318                                 u32 new_state)
 319 {
 320         struct hlist_head *chain;
 321         struct hlist_node *pos;
 322         struct nsm_handle *nsm;
 323         struct nlm_host *host;
 324
 325         dprintk("lockd: nlm_host_rebooted(%s, %u.%u.%u.%u)\n",
 326                         hostname, NIPQUAD(sin->sin_addr));
 327
 328         /* Find the NSM handle for this peer */
 329         if (!(nsm = __nsm_find(sin, hostname, hostname_len, 0)))
 330                 return;
 331
 332         /* When reclaiming locks on this peer, make sure that
 333          * we set up a new notification */
 334         nsm->sm_monitored = 0;
 335
 336         /* Mark all hosts tied to this NSM state as having rebooted.
 337          * We run the loop repeatedly, because we drop the host table
 338          * lock for this.
 339          * To avoid processing a host several times, we match the nsmstate.
 340          */
 341 again:  mutex_lock(&nlm_host_mutex);
 342         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 343                 hlist_for_each_entry(host, pos, chain, h_hash) {
 344                         if (host->h_nsmhandle == nsm
 345                          && host->h_nsmstate != new_state) {
 346                                 host->h_nsmstate = new_state;
 347                                 host->h_state++;
 348
 349                                 nlm_get_host(host);
 350                                 mutex_unlock(&nlm_host_mutex);
 351
 352                                 if (host->h_server) {
 353                                         /* We're server for this guy, just ditch
 354                                          * all the locks he held. */
 355                                         nlmsvc_free_host_resources(host);
 356                                 } else {
 357                                         /* He's the server, initiate lock recovery. */
 358                                         nlmclnt_recovery(host);
 359                                 }
 360
 361                                 nlm_release_host(host);
 362                                 goto again;
 363                         }
 364                 }
 365         }
 366
 367         mutex_unlock(&nlm_host_mutex);
 368 }
 369
 370 /*
 371  * Shut down the hosts module.
 372  * Note that this routine is called only at server shutdown time.
 373  */
 374 void
 375 nlm_shutdown_hosts(void)
 376 {
 377         struct hlist_head *chain;
 378         struct hlist_node *pos;
 379         struct nlm_host *host;
 380
 381         dprintk("lockd: shutting down host module\n");
 382         mutex_lock(&nlm_host_mutex);
 383
 384         /* First, make all hosts eligible for gc */
 385         dprintk("lockd: nuking all hosts...\n");
 386         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 387                 hlist_for_each_entry(host, pos, chain, h_hash) {
 388                         host->h_expires = jiffies - 1;
 389                         if (host->h_rpcclnt) {
 390                                 rpc_shutdown_client(host->h_rpcclnt);
 391                                 host->h_rpcclnt = NULL;
 392                         }
 393                 }
 394         }
 395
 396         /* Then, perform a garbage collection pass */
 397         nlm_gc_hosts();
 398         mutex_unlock(&nlm_host_mutex);
 399
 400         /* complain if any hosts are left */
 401         if (nrhosts) {
 402                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
 403                 dprintk("lockd: %d hosts left:\n", nrhosts);
 404                 for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 405                         hlist_for_each_entry(host, pos, chain, h_hash) {
 406                                 dprintk("       %s (cnt %d use %d exp %ld)\n",
 407                                         host->h_name, atomic_read(&host->h_count),
 408                                         host->h_inuse, host->h_expires);
 409                         }
 410                 }
 411         }
 412 }
 413
 414 /*
 415  * Garbage collect any unused NLM hosts.
 416  * This GC combines reference counting for async operations with
 417  * mark & sweep for resources held by remote clients.
 418  */
 419 static void
 420 nlm_gc_hosts(void)
 421 {
 422         struct hlist_head *chain;
 423         struct hlist_node *pos, *next;
 424         struct nlm_host *host;
 425
 426         dprintk("lockd: host garbage collection\n");
 427         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 428                 hlist_for_each_entry(host, pos, chain, h_hash)
 429                         host->h_inuse = 0;
 430         }
 431
 432         /* Mark all hosts that hold locks, blocks or shares */
 433         nlmsvc_mark_resources();
 434
 435         for (chain = nlm_hosts; chain < nlm_hosts + NLM_HOST_NRHASH; ++chain) {
 436                 hlist_for_each_entry_safe(host, pos, next, chain, h_hash) {
 437                         if (atomic_read(&host->h_count) || host->h_inuse
 438                          || time_before(jiffies, host->h_expires)) {
 439                                 dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
 440                                         host->h_name, atomic_read(&host->h_count),
 441                                         host->h_inuse, host->h_expires);
 442                                 continue;
 443                         }
 444                         dprintk("lockd: delete host %s\n", host->h_name);
 445                         hlist_del_init(&host->h_hash);
 446
 447                         nlm_destroy_host(host);
 448                         nrhosts--;
 449                 }
 450         }
 451
 452         next_gc = jiffies + NLM_HOST_COLLECT;
 453 }
 454
 455
 456 /*
 457  * Manage NSM handles
 458  */
 459 static LIST_HEAD(nsm_handles);
 460 static DEFINE_MUTEX(nsm_mutex);
 461
 462 static struct nsm_handle *
 463 __nsm_find(const struct sockaddr_in *sin,
 464                 const char *hostname, unsigned int hostname_len,
 465                 int create)
 466 {
 467         struct nsm_handle *nsm = NULL;
 468         struct list_head *pos;
 469
 470         if (!sin)
 471                 return NULL;
 472
 473         if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
 474                 if (printk_ratelimit()) {
 475                         printk(KERN_WARNING "Invalid hostname \"%.*s\" "
 476                                             "in NFS lock request\n",
 477                                 hostname_len, hostname);
 478                 }
 479                 return NULL;
 480         }
 481
 482         mutex_lock(&nsm_mutex);
 483         list_for_each(pos, &nsm_handles) {
 484                 nsm = list_entry(pos, struct nsm_handle, sm_link);
 485
 486                 if (hostname && nsm_use_hostnames) {
 487                         if (strlen(nsm->sm_name) != hostname_len
 488                          || memcmp(nsm->sm_name, hostname, hostname_len))
 489                                 continue;
 490                 } else if (!nlm_cmp_addr(&nsm->sm_addr, sin))
 491                         continue;
 492                 atomic_inc(&nsm->sm_count);
 493                 goto out;
 494         }
 495
 496         if (!create) {
 497                 nsm = NULL;
 498                 goto out;
 499         }
 500
 501         nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL);
 502         if (nsm != NULL) {
 503                 nsm->sm_addr = *sin;
 504                 nsm->sm_name = (char *) (nsm + 1);
 505                 memcpy(nsm->sm_name, hostname, hostname_len);
 506                 nsm->sm_name[hostname_len] = '\0';
 507                 atomic_set(&nsm->sm_count, 1);
 508
 509                 list_add(&nsm->sm_link, &nsm_handles);
 510         }
 511
 512 out:
 513         mutex_unlock(&nsm_mutex);
 514         return nsm;
 515 }
 516
 517 static struct nsm_handle *
 518 nsm_find(const struct sockaddr_in *sin, const char *hostname,
 519          unsigned int hostname_len)
 520 {
 521         return __nsm_find(sin, hostname, hostname_len, 1);
 522 }
 523
 524 /*
 525  * Release an NSM handle
 526  */
 527 void
 528 nsm_release(struct nsm_handle *nsm)
 529 {
 530         if (!nsm)
 531                 return;
 532         mutex_lock(&nsm_mutex);
 533         if (atomic_dec_and_test(&nsm->sm_count)) {
 534                 list_del(&nsm->sm_link);
 535                 kfree(nsm);
 536         }
 537         mutex_unlock(&nsm_mutex);
 538 }