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
  20
  21 #define NLMDBG_FACILITY         NLMDBG_HOSTCACHE
  22 #define NLM_HOST_MAX            64
  23 #define NLM_HOST_NRHASH         32
  24 #define NLM_ADDRHASH(addr)      (ntohl(addr) & (NLM_HOST_NRHASH-1))
  25 #define NLM_HOST_REBIND         (60 * HZ)
  26 #define NLM_HOST_EXPIRE         ((nrhosts > NLM_HOST_MAX)? 300 * HZ : 120 * HZ)
  27 #define NLM_HOST_COLLECT        ((nrhosts > NLM_HOST_MAX)? 120 * HZ :  60 * HZ)
  28 #define NLM_HOST_ADDR(sv)       (&(sv)->s_nlmclnt->cl_xprt->addr)
  29
  30 static struct nlm_host *        nlm_hosts[NLM_HOST_NRHASH];
  31 static unsigned long            next_gc;
  32 static int                      nrhosts;
  33 static DECLARE_MUTEX(nlm_host_sema);
  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         down(&nlm_host_sema);
  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                         up(&nlm_host_sema);
  95                         return host;
  96                 }
  97         }
  98
  99         /* Ooops, no host found, create it */
 100         dprintk("lockd: creating host entry\n");
 101
 102         if (!(host = (struct nlm_host *) kmalloc(sizeof(*host), GFP_KERNEL)))
 103                 goto nohost;
 104         memset(host, 0, sizeof(*host));
 105
 106         addr = sin->sin_addr.s_addr;
 107         sprintf(host->h_name, "%d.%d.%d.%d",
 108                         (unsigned char) (ntohl(addr) >> 24),
 109                         (unsigned char) (ntohl(addr) >> 16),
 110                         (unsigned char) (ntohl(addr) >>  8),
 111                         (unsigned char) (ntohl(addr) >>  0));
 112
 113         host->h_addr       = *sin;
 114         host->h_addr.sin_port = 0;      /* ouch! */
 115         host->h_version    = version;
 116         host->h_proto      = proto;
 117         host->h_authflavor = RPC_AUTH_UNIX;
 118         host->h_rpcclnt    = NULL;
 119         init_MUTEX(&host->h_sema);
 120         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 121         host->h_expires    = jiffies + NLM_HOST_EXPIRE;
 122         atomic_set(&host->h_count, 1);
 123         init_waitqueue_head(&host->h_gracewait);
 124         host->h_state      = 0;                 /* pseudo NSM state */
 125         host->h_nsmstate   = 0;                 /* real NSM state */
 126         host->h_server     = server;
 127         host->h_next       = nlm_hosts[hash];
 128         nlm_hosts[hash]    = host;
 129         INIT_LIST_HEAD(&host->h_lockowners);
 130         spin_lock_init(&host->h_lock);
 131
 132         if (++nrhosts > NLM_HOST_MAX)
 133                 next_gc = 0;
 134
 135 nohost:
 136         up(&nlm_host_sema);
 137         return host;
 138 }
 139
 140 struct nlm_host *
 141 nlm_find_client(void)
 142 {
 143         /* find a nlm_host for a client for which h_killed == 0.
 144          * and return it
 145          */
 146         int hash;
 147         down(&nlm_host_sema);
 148         for (hash = 0 ; hash < NLM_HOST_NRHASH; hash++) {
 149                 struct nlm_host *host, **hp;
 150                 for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) {
 151                         if (host->h_server &&
 152                             host->h_killed == 0) {
 153                                 nlm_get_host(host);
 154                                 up(&nlm_host_sema);
 155                                 return host;
 156                         }
 157                 }
 158         }
 159         up(&nlm_host_sema);
 160         return NULL;
 161 }
 162
 163
 164 /*
 165  * Create the NLM RPC client for an NLM peer
 166  */
 167 struct rpc_clnt *
 168 nlm_bind_host(struct nlm_host *host)
 169 {
 170         struct rpc_clnt *clnt;
 171         struct rpc_xprt *xprt;
 172
 173         dprintk("lockd: nlm_bind_host(%08x)\n",
 174                         (unsigned)ntohl(host->h_addr.sin_addr.s_addr));
 175
 176         /* Lock host handle */
 177         down(&host->h_sema);
 178
 179         /* If we've already created an RPC client, check whether
 180          * RPC rebind is required
 181          * Note: why keep rebinding if we're on a tcp connection?
 182          */
 183         if ((clnt = host->h_rpcclnt) != NULL) {
 184                 xprt = clnt->cl_xprt;
 185                 if (!xprt->stream && time_after_eq(jiffies, host->h_nextrebind)) {
 186                         clnt->cl_port = 0;
 187                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 188                         dprintk("lockd: next rebind in %ld jiffies\n",
 189                                         host->h_nextrebind - jiffies);
 190                 }
 191         } else {
 192                 xprt = xprt_create_proto(host->h_proto, &host->h_addr, NULL);
 193                 if (IS_ERR(xprt))
 194                         goto forgetit;
 195
 196                 xprt_set_timeout(&xprt->timeout, 5, nlmsvc_timeout);
 197
 198                 clnt = rpc_create_client(xprt, host->h_name, &nlm_program,
 199                                         host->h_version, host->h_authflavor);
 200                 if (IS_ERR(clnt)) {
 201                         xprt_destroy(xprt);
 202                         goto forgetit;
 203                 }
 204                 clnt->cl_autobind = 1;  /* turn on pmap queries */
 205                 xprt->nocong = 1;       /* No congestion control for NLM */
 206                 xprt->resvport = 1;     /* NLM requires a reserved port */
 207
 208                 host->h_rpcclnt = clnt;
 209         }
 210
 211         up(&host->h_sema);
 212         return clnt;
 213
 214 forgetit:
 215         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
 216         up(&host->h_sema);
 217         return NULL;
 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                 host->h_rpcclnt->cl_port = 0;
 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                 atomic_dec(&host->h_count);
 254                 BUG_ON(atomic_read(&host->h_count) < 0);
 255         }
 256 }
 257
 258 /*
 259  * Shut down the hosts module.
 260  * Note that this routine is called only at server shutdown time.
 261  */
 262 void
 263 nlm_shutdown_hosts(void)
 264 {
 265         struct nlm_host *host;
 266         int             i;
 267
 268         dprintk("lockd: shutting down host module\n");
 269         down(&nlm_host_sema);
 270
 271         /* First, make all hosts eligible for gc */
 272         dprintk("lockd: nuking all hosts...\n");
 273         for (i = 0; i < NLM_HOST_NRHASH; i++) {
 274                 for (host = nlm_hosts[i]; host; host = host->h_next)
 275                         host->h_expires = jiffies - 1;
 276         }
 277
 278         /* Then, perform a garbage collection pass */
 279         nlm_gc_hosts();
 280         up(&nlm_host_sema);
 281
 282         /* complain if any hosts are left */
 283         if (nrhosts) {
 284                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
 285                 dprintk("lockd: %d hosts left:\n", nrhosts);
 286                 for (i = 0; i < NLM_HOST_NRHASH; i++) {
 287                         for (host = nlm_hosts[i]; host; host = host->h_next) {
 288                                 dprintk("       %s (cnt %d use %d exp %ld)\n",
 289                                         host->h_name, atomic_read(&host->h_count),
 290                                         host->h_inuse, host->h_expires);
 291                         }
 292                 }
 293         }
 294 }
 295
 296 /*
 297  * Garbage collect any unused NLM hosts.
 298  * This GC combines reference counting for async operations with
 299  * mark & sweep for resources held by remote clients.
 300  */
 301 static void
 302 nlm_gc_hosts(void)
 303 {
 304         struct nlm_host **q, *host;
 305         struct rpc_clnt *clnt;
 306         int             i;
 307
 308         dprintk("lockd: host garbage collection\n");
 309         for (i = 0; i < NLM_HOST_NRHASH; i++) {
 310                 for (host = nlm_hosts[i]; host; host = host->h_next)
 311                         host->h_inuse = 0;
 312         }
 313
 314         /* Mark all hosts that hold locks, blocks or shares */
 315         nlmsvc_mark_resources();
 316
 317         for (i = 0; i < NLM_HOST_NRHASH; i++) {
 318                 q = &nlm_hosts[i];
 319                 while ((host = *q) != NULL) {
 320                         if (atomic_read(&host->h_count) || host->h_inuse
 321                          || time_before(jiffies, host->h_expires)) {
 322                                 dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
 323                                         host->h_name, atomic_read(&host->h_count),
 324                                         host->h_inuse, host->h_expires);
 325                                 q = &host->h_next;
 326                                 continue;
 327                         }
 328                         dprintk("lockd: delete host %s\n", host->h_name);
 329                         *q = host->h_next;
 330                         /* Don't unmonitor hosts that have been invalidated */
 331                         if (host->h_monitored && !host->h_killed)
 332                                 nsm_unmonitor(host);
 333                         if ((clnt = host->h_rpcclnt) != NULL) {
 334                                 if (atomic_read(&clnt->cl_users)) {
 335                                         printk(KERN_WARNING
 336                                                 "lockd: active RPC handle\n");
 337                                         clnt->cl_dead = 1;
 338                                 } else {
 339                                         rpc_destroy_client(host->h_rpcclnt);
 340                                 }
 341                         }
 342                         BUG_ON(!list_empty(&host->h_lockowners));
 343                         kfree(host);
 344                         nrhosts--;
 345                 }
 346         }
 347
 348         next_gc = jiffies + NLM_HOST_COLLECT;
 349 }
 350