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_PTRHASH(ptr)        ((((u32)(unsigned long) ptr) / 32) & (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 #define NLM_HOST_ADDR(sv)       (&(sv)->s_nlmclnt->cl_xprt->addr)
  30
  31 static struct nlm_host *        nlm_hosts[NLM_HOST_NRHASH];
  32 static unsigned long            next_gc;
  33 static int                      nrhosts;
  34 static DECLARE_MUTEX(nlm_host_sema);
  35
  36
  37 static void                     nlm_gc_hosts(void);
  38
  39 /*
  40  * Find an NLM server handle in the cache. If there is none, create it.
  41  */
  42 struct nlm_host *
  43 nlmclnt_lookup_host(struct sockaddr_in *sin, int proto, int version)
  44 {
  45         return nlm_lookup_host(NULL, sin, proto, version);
  46 }
  47
  48 /*
  49  * Find an NLM client handle in the cache. If there is none, create it.
  50  */
  51 struct nlm_host *
  52 nlmsvc_lookup_host(struct svc_rqst *rqstp)
  53 {
  54         return nlm_lookup_host(rqstp->rq_client, &rqstp->rq_addr,
  55                                rqstp->rq_prot, rqstp->rq_vers);
  56 }
  57
  58 /*
  59  * Match the given host against client/address
  60  */
  61 static inline int
  62 nlm_match_host(struct nlm_host *host, struct svc_client *clnt,
  63                                         struct sockaddr_in *sin)
  64 {
  65         if (clnt)
  66                 return host->h_exportent == clnt;
  67         return nlm_cmp_addr(&host->h_addr, sin);
  68 }
  69
  70 /*
  71  * Common host lookup routine for server & client
  72  */
  73 struct nlm_host *
  74 nlm_lookup_host(struct svc_client *clnt, struct sockaddr_in *sin,
  75                                         int proto, int version)
  76 {
  77         struct nlm_host *host, **hp;
  78         u32             addr;
  79         int             hash;
  80
  81         if (!clnt && !sin) {
  82                 printk(KERN_NOTICE "lockd: no clnt or addr in lookup_host!\n");
  83                 return NULL;
  84         }
  85
  86         dprintk("lockd: nlm_lookup_host(%08x, p=%d, v=%d)\n",
  87                         (unsigned)(sin? ntohl(sin->sin_addr.s_addr) : 0), proto, version);
  88
  89         if (clnt)
  90                 hash = NLM_PTRHASH(clnt);
  91         else
  92                 hash = NLM_ADDRHASH(sin->sin_addr.s_addr);
  93
  94         /* Lock hash table */
  95         down(&nlm_host_sema);
  96
  97         if (time_after_eq(jiffies, next_gc))
  98                 nlm_gc_hosts();
  99
 100         for (hp = &nlm_hosts[hash]; (host = *hp); hp = &host->h_next) {
 101                 if (proto && host->h_proto != proto)
 102                         continue;
 103                 if (version && host->h_version != version)
 104                         continue;
 105
 106                 if (nlm_match_host(host, clnt, sin)) {
 107                         if (hp != nlm_hosts + hash) {
 108                                 *hp = host->h_next;
 109                                 host->h_next = nlm_hosts[hash];
 110                                 nlm_hosts[hash] = host;
 111                         }
 112                         nlm_get_host(host);
 113                         up(&nlm_host_sema);
 114                         return host;
 115                 }
 116         }
 117
 118         /* special hack for nlmsvc_invalidate_client */
 119         if (sin == NULL)
 120                 goto nohost;
 121
 122         /* Ooops, no host found, create it */
 123         dprintk("lockd: creating host entry\n");
 124
 125         if (!(host = (struct nlm_host *) kmalloc(sizeof(*host), GFP_KERNEL)))
 126                 goto nohost;
 127         memset(host, 0, sizeof(*host));
 128
 129         addr = sin->sin_addr.s_addr;
 130         sprintf(host->h_name, "%d.%d.%d.%d",
 131                         (unsigned char) (ntohl(addr) >> 24),
 132                         (unsigned char) (ntohl(addr) >> 16),
 133                         (unsigned char) (ntohl(addr) >>  8),
 134                         (unsigned char) (ntohl(addr) >>  0));
 135
 136         host->h_addr       = *sin;
 137         host->h_addr.sin_port = 0;      /* ouch! */
 138         host->h_version    = version;
 139         host->h_proto      = proto;
 140         host->h_authflavor = RPC_AUTH_UNIX;
 141         host->h_rpcclnt    = NULL;
 142         init_MUTEX(&host->h_sema);
 143         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 144         host->h_expires    = jiffies + NLM_HOST_EXPIRE;
 145         host->h_count      = 1;
 146         init_waitqueue_head(&host->h_gracewait);
 147         host->h_state      = 0;                 /* pseudo NSM state */
 148         host->h_nsmstate   = 0;                 /* real NSM state */
 149         host->h_exportent  = clnt;
 150
 151         host->h_next       = nlm_hosts[hash];
 152         nlm_hosts[hash]    = host;
 153
 154         if (++nrhosts > NLM_HOST_MAX)
 155                 next_gc = 0;
 156
 157 nohost:
 158         up(&nlm_host_sema);
 159         return host;
 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         struct rpc_xprt *xprt;
 170
 171         dprintk("lockd: nlm_bind_host(%08x)\n",
 172                         (unsigned)ntohl(host->h_addr.sin_addr.s_addr));
 173
 174         /* Lock host handle */
 175         down(&host->h_sema);
 176
 177         /* If we've already created an RPC client, check whether
 178          * RPC rebind is required
 179          * Note: why keep rebinding if we're on a tcp connection?
 180          */
 181         if ((clnt = host->h_rpcclnt) != NULL) {
 182                 xprt = clnt->cl_xprt;
 183                 if (!xprt->stream && time_after_eq(jiffies, host->h_nextrebind)) {
 184                         clnt->cl_port = 0;
 185                         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 186                         dprintk("lockd: next rebind in %ld jiffies\n",
 187                                         host->h_nextrebind - jiffies);
 188                 }
 189         } else {
 190                 uid_t saved_fsuid = current->fsuid;
 191                 kernel_cap_t saved_cap = current->cap_effective;
 192
 193                 /* Create RPC socket as root user so we get a priv port */
 194                 current->fsuid = 0;
 195                 cap_raise (current->cap_effective, CAP_NET_BIND_SERVICE);
 196                 xprt = xprt_create_proto(host->h_proto, &host->h_addr, NULL);
 197                 current->fsuid = saved_fsuid;
 198                 current->cap_effective = saved_cap;
 199                 if (xprt == NULL)
 200                         goto forgetit;
 201
 202                 xprt_set_timeout(&xprt->timeout, 5, nlmsvc_timeout);
 203
 204                 clnt = rpc_create_client(xprt, host->h_name, &nlm_program,
 205                                         host->h_version, host->h_authflavor);
 206                 if (clnt == NULL) {
 207                         xprt_destroy(xprt);
 208                         goto forgetit;
 209                 }
 210                 clnt->cl_autobind = 1;  /* turn on pmap queries */
 211                 xprt->nocong = 1;       /* No congestion control for NLM */
 212
 213                 host->h_rpcclnt = clnt;
 214         }
 215
 216         up(&host->h_sema);
 217         return clnt;
 218
 219 forgetit:
 220         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
 221         up(&host->h_sema);
 222         return NULL;
 223 }
 224
 225 /*
 226  * Force a portmap lookup of the remote lockd port
 227  */
 228 void
 229 nlm_rebind_host(struct nlm_host *host)
 230 {
 231         dprintk("lockd: rebind host %s\n", host->h_name);
 232         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
 233                 host->h_rpcclnt->cl_port = 0;
 234                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 235         }
 236 }
 237
 238 /*
 239  * Increment NLM host count
 240  */
 241 struct nlm_host * nlm_get_host(struct nlm_host *host)
 242 {
 243         if (host) {
 244                 dprintk("lockd: get host %s\n", host->h_name);
 245                 host->h_count ++;
 246                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
 247         }
 248         return host;
 249 }
 250
 251 /*
 252  * Release NLM host after use
 253  */
 254 void nlm_release_host(struct nlm_host *host)
 255 {
 256         if (host && host->h_count) {
 257                 dprintk("lockd: release host %s\n", host->h_name);
 258                 host->h_count --;
 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         down(&nlm_host_sema);
 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 = 0;
 280         }
 281
 282         /* Then, perform a garbage collection pass */
 283         nlm_gc_hosts();
 284         up(&nlm_host_sema);
 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, 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 (host->h_count || host->h_inuse
 325                          || time_before(jiffies, host->h_expires)) {
 326                                 q = &host->h_next;
 327                                 continue;
 328                         }
 329                         dprintk("lockd: delete host %s\n", host->h_name);
 330                         *q = host->h_next;
 331                         /* Don't unmonitor hosts that have been invalidated */
 332                         if (host->h_monitored && !host->h_killed)
 333                                 nsm_unmonitor(host);
 334                         if ((clnt = host->h_rpcclnt) != NULL) {
 335                                 if (atomic_read(&clnt->cl_users)) {
 336                                         printk(KERN_WARNING
 337                                                 "lockd: active RPC handle\n");
 338                                         clnt->cl_dead = 1;
 339                                 } else {
 340                                         rpc_destroy_client(host->h_rpcclnt);
 341                                 }
 342                         }
 343                         kfree(host);
 344                         nrhosts--;
 345                 }
 346         }
 347
 348         next_gc = jiffies + NLM_HOST_COLLECT;
 349 }
 350