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/sched.h>
  13 #include <linux/slab.h>
  14 #include <linux/in.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
  22 #define NLMDBG_FACILITY         NLMDBG_HOSTCACHE
  23 #define NLM_HOST_MAX            64
  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         ((nrhosts > NLM_HOST_MAX)? 300 * HZ : 120 * HZ)
  28 #define NLM_HOST_COLLECT        ((nrhosts > NLM_HOST_MAX)? 120 * HZ :  60 * HZ)
  29
  30 static struct nlm_host *        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
  38 /*
  39  * Find an NLM server handle in the cache. If there is none, create it.
  40  */
  41 struct nlm_host *
  42 nlmclnt_lookup_host(struct sockaddr_in *sin, int proto, int version)
  43 {
  44         return nlm_lookup_host(0, sin, proto, version);
  45 }
  46
  47 /*
  48  * Find an NLM client handle in the cache. If there is none, create it.
  49  */
  50 struct nlm_host *
  51 nlmsvc_lookup_host(struct svc_rqst *rqstp)
  52 {
  53         return nlm_lookup_host(1, &rqstp->rq_addr,
  54                                rqstp->rq_prot, rqstp->rq_vers);
  55 }
  56
  57 /*
  58  * Common host lookup routine for server & client
  59  */
  60 struct nlm_host *
  61 nlm_lookup_host(int server, struct sockaddr_in *sin,
  62                                         int proto, int version)
  63 {
  64         struct nlm_host *host, **hp;
  65         u32             addr;
  66         int             hash;
  67
  68         dprintk("lockd: nlm_lookup_host(%08x, p=%d, v=%d)\n",
  69                         (unsigned)(sin? ntohl(sin->sin_addr.s_addr) : 0), proto, version);
  70
  71         hash = NLM_ADDRHASH(sin->sin_addr.s_addr);
  72
  73         /* Lock hash table */
  74         mutex_lock(&nlm_host_mutex);
  75
  76         if (time_after_eq(jiffies, next_gc))
  77                 nlm_gc_hosts();
  78
  79         for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) {
  80                 if (host->h_proto != proto)
  81                         continue;
  82                 if (host->h_version != version)
  83                         continue;
  84                 if (host->h_server != server)
  85                         continue;
  86
  87                 if (nlm_cmp_addr(&host->h_addr, sin)) {
  88                         if (hp != nlm_hosts + hash) {
  89                                 *hp = host->h_next;
  90                                 host->h_next = nlm_hosts[hash];
  91                                 nlm_hosts[hash] = host;
  92                         }
  93                         nlm_get_host(host);
  94                         mutex_unlock(&nlm_host_mutex);
  95                         return host;
  96                 }
  97         }
  98
  99         /* Ooops, no host found, create it */
 100         dprintk("lockd: creating host entry\n");
 101
 102         host = kzalloc(sizeof(*host), GFP_KERNEL);
 103         if (!host)
 104                 goto nohost;
 105
 106         addr = sin->sin_addr.s_addr;
 107         sprintf(host->h_name, "%u.%u.%u.%u", NIPQUAD(addr));
 108
 109         host->h_addr       = *sin;
 110         host->h_addr.sin_port = 0;      /* ouch! */
 111         host->h_version    = version;
 112         host->h_proto      = proto;
 113         host->h_rpcclnt    = NULL;
 114         mutex_init(&host->h_mutex);
 115         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 116         host->h_expires    = jiffies + NLM_HOST_EXPIRE;
 117         atomic_set(&host->h_count, 1);
 118         init_waitqueue_head(&host->h_gracewait);
 119         init_rwsem(&host->h_rwsem);
 120         host->h_state      = 0;                 /* pseudo NSM state */
 121         host->h_nsmstate   = 0;                 /* real NSM state */
 122         host->h_server     = server;
 123         host->h_next       = nlm_hosts[hash];
 124         nlm_hosts[hash]    = host;
 125         INIT_LIST_HEAD(&host->h_lockowners);
 126         spin_lock_init(&host->h_lock);
 127         INIT_LIST_HEAD(&host->h_granted);
 128         INIT_LIST_HEAD(&host->h_reclaim);
 129
 130         if (++nrhosts > NLM_HOST_MAX)
 131                 next_gc = 0;
 132
 133 nohost:
 134         mutex_unlock(&nlm_host_mutex);
 135         return host;
 136 }
 137
 138 struct nlm_host *
 139 nlm_find_client(void)
 140 {
 141         /* find a nlm_host for a client for which h_killed == 0.
 142          * and return it
 143          */
 144         int hash;
 145         mutex_lock(&nlm_host_mutex);
 146         for (hash = 0 ; hash < NLM_HOST_NRHASH; hash++) {
 147                 struct nlm_host *host, **hp;
 148                 for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) {
 149                         if (host->h_server &&
 150                             host->h_killed == 0) {
 151                                 nlm_get_host(host);
 152                                 mutex_unlock(&nlm_host_mutex);
 153                                 return host;
 154                         }
 155                 }
 156         }
 157         mutex_unlock(&nlm_host_mutex);
 158         return NULL;
 159 }
 160
 161
 162 /*
 163  * Create the NLM RPC client for an NLM peer
 164  */
 165 struct rpc_clnt *
 166 nlm_bind_host(struct nlm_host *host)
 167 {
 168         struct rpc_clnt *clnt;
 169
 170         dprintk("lockd: nlm_bind_host(%08x)\n",
 171                         (unsigned)ntohl(host->h_addr.sin_addr.s_addr));
 172
 173         /* Lock host handle */
 174         mutex_lock(&host->h_mutex);
 175
 176         /* If we've already created an RPC client, check whether
 177          * RPC rebind is required
 178          */
 179         if ((clnt = host->h_rpcclnt) != NULL) {
 180                 if (time_after_eq(jiffies, host->h_nextrebind)) {
 181                         rpc_force_rebind(clnt);
 182                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 183                         dprintk("lockd: next rebind in %ld jiffies\n",
 184                                         host->h_nextrebind - jiffies);
 185                 }
 186         } else {
 187                 unsigned long increment = nlmsvc_timeout * HZ;
 188                 struct rpc_timeout timeparms = {
 189                         .to_initval     = increment,
 190                         .to_increment   = increment,
 191                         .to_maxval      = increment * 6UL,
 192                         .to_retries     = 5U,
 193                 };
 194                 struct rpc_create_args args = {
 195                         .protocol       = host->h_proto,
 196                         .address        = (struct sockaddr *)&host->h_addr,
 197                         .addrsize       = sizeof(host->h_addr),
 198                         .timeout        = &timeparms,
 199                         .servername     = host->h_name,
 200                         .program        = &nlm_program,
 201                         .version        = host->h_version,
 202                         .authflavor     = RPC_AUTH_UNIX,
 203                         .flags          = (RPC_CLNT_CREATE_HARDRTRY |
 204                                            RPC_CLNT_CREATE_AUTOBIND),
 205                 };
 206
 207                 clnt = rpc_create(&args);
 208                 if (!IS_ERR(clnt))
 209                         host->h_rpcclnt = clnt;
 210                 else {
 211                         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
 212                         clnt = NULL;
 213                 }
 214         }
 215
 216         mutex_unlock(&host->h_mutex);
 217         return clnt;
 218 }
 219
 220 /*
 221  * Force a portmap lookup of the remote lockd port
 222  */
 223 void
 224 nlm_rebind_host(struct nlm_host *host)
 225 {
 226         dprintk("lockd: rebind host %s\n", host->h_name);
 227         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
 228                 rpc_force_rebind(host->h_rpcclnt);
 229                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 230         }
 231 }
 232
 233 /*
 234  * Increment NLM host count
 235  */
 236 struct nlm_host * nlm_get_host(struct nlm_host *host)
 237 {
 238         if (host) {
 239                 dprintk("lockd: get host %s\n", host->h_name);
 240                 atomic_inc(&host->h_count);
 241                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
 242         }
 243         return host;
 244 }
 245
 246 /*
 247  * Release NLM host after use
 248  */
 249 void nlm_release_host(struct nlm_host *host)
 250 {
 251         if (host != NULL) {
 252                 dprintk("lockd: release host %s\n", host->h_name);
 253                 BUG_ON(atomic_read(&host->h_count) < 0);
 254                 if (atomic_dec_and_test(&host->h_count)) {
 255                         BUG_ON(!list_empty(&host->h_lockowners));
 256                         BUG_ON(!list_empty(&host->h_granted));
 257                         BUG_ON(!list_empty(&host->h_reclaim));
 258                 }
 259         }
 260 }
 261
 262 /*
 263  * Shut down the hosts module.
 264  * Note that this routine is called only at server shutdown time.
 265  */
 266 void
 267 nlm_shutdown_hosts(void)
 268 {
 269         struct nlm_host *host;
 270         int             i;
 271
 272         dprintk("lockd: shutting down host module\n");
 273         mutex_lock(&nlm_host_mutex);
 274
 275         /* First, make all hosts eligible for gc */
 276         dprintk("lockd: nuking all hosts...\n");
 277         for (i = 0; i < NLM_HOST_NRHASH; i++) {
 278                 for (host = nlm_hosts[i]; host; host = host->h_next)
 279                         host->h_expires = jiffies - 1;
 280         }
 281
 282         /* Then, perform a garbage collection pass */
 283         nlm_gc_hosts();
 284         mutex_unlock(&nlm_host_mutex);
 285
 286         /* complain if any hosts are left */
 287         if (nrhosts) {
 288                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
 289                 dprintk("lockd: %d hosts left:\n", nrhosts);
 290                 for (i = 0; i < NLM_HOST_NRHASH; i++) {
 291                         for (host = nlm_hosts[i]; host; host = host->h_next) {
 292                                 dprintk("       %s (cnt %d use %d exp %ld)\n",
 293                                         host->h_name, atomic_read(&host->h_count),
 294                                         host->h_inuse, host->h_expires);
 295                         }
 296                 }
 297         }
 298 }
 299
 300 /*
 301  * Garbage collect any unused NLM hosts.
 302  * This GC combines reference counting for async operations with
 303  * mark & sweep for resources held by remote clients.
 304  */
 305 static void
 306 nlm_gc_hosts(void)
 307 {
 308         struct nlm_host **q, *host;
 309         struct rpc_clnt *clnt;
 310         int             i;
 311
 312         dprintk("lockd: host garbage collection\n");
 313         for (i = 0; i < NLM_HOST_NRHASH; i++) {
 314                 for (host = nlm_hosts[i]; host; host = host->h_next)
 315                         host->h_inuse = 0;
 316         }
 317
 318         /* Mark all hosts that hold locks, blocks or shares */
 319         nlmsvc_mark_resources();
 320
 321         for (i = 0; i < NLM_HOST_NRHASH; i++) {
 322                 q = &nlm_hosts[i];
 323                 while ((host = *q) != NULL) {
 324                         if (atomic_read(&host->h_count) || host->h_inuse
 325                          || time_before(jiffies, host->h_expires)) {
 326                                 dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
 327                                         host->h_name, atomic_read(&host->h_count),
 328                                         host->h_inuse, host->h_expires);
 329                                 q = &host->h_next;
 330                                 continue;
 331                         }
 332                         dprintk("lockd: delete host %s\n", host->h_name);
 333                         *q = host->h_next;
 334                         /* Don't unmonitor hosts that have been invalidated */
 335                         if (host->h_monitored && !host->h_killed)
 336                                 nsm_unmonitor(host);
 337                         if ((clnt = host->h_rpcclnt) != NULL) {
 338                                 if (atomic_read(&clnt->cl_users)) {
 339                                         printk(KERN_WARNING
 340                                                 "lockd: active RPC handle\n");
 341                                         clnt->cl_dead = 1;
 342                                 } else {
 343                                         rpc_destroy_client(host->h_rpcclnt);
 344                                 }
 345                         }
 346                         kfree(host);
 347                         nrhosts--;
 348                 }
 349         }
 350
 351         next_gc = jiffies + NLM_HOST_COLLECT;
 352 }
 353