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/malloc.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 = 0;
  33 static int                      nrhosts = 0;
  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, 0, 0);
  55 }
  56
  57 /*
  58  * Match the given host against client/address
  59  */
  60 static inline int
  61 nlm_match_host(struct nlm_host *host, struct svc_client *clnt,
  62                                         struct sockaddr_in *sin)
  63 {
  64         if (clnt)
  65                 return host->h_exportent == clnt;
  66         return nlm_cmp_addr(&host->h_addr, sin);
  67 }
  68
  69 /*
  70  * Common host lookup routine for server & client
  71  */
  72 struct nlm_host *
  73 nlm_lookup_host(struct svc_client *clnt, struct sockaddr_in *sin,
  74                                         int proto, int version)
  75 {
  76         struct nlm_host *host, **hp;
  77         u32             addr;
  78         int             hash;
  79
  80         if (!clnt && !sin) {
  81                 printk(KERN_NOTICE "lockd: no clnt or addr in lookup_host!\n");
  82                 return NULL;
  83         }
  84
  85         dprintk("lockd: nlm_lookup_host(%08x, p=%d, v=%d)\n",
  86                         (unsigned)(sin? ntohl(sin->sin_addr.s_addr) : 0), proto, version);
  87
  88         if (clnt)
  89                 hash = NLM_PTRHASH(clnt);
  90         else
  91                 hash = NLM_ADDRHASH(sin->sin_addr.s_addr);
  92
  93         /* Lock hash table */
  94         down(&nlm_host_sema);
  95
  96         if (time_after_eq(jiffies, next_gc))
  97                 nlm_gc_hosts();
  98
  99         for (hp = &nlm_hosts[hash]; (host = *hp); hp = &host->h_next) {
 100                 if (host->h_version != version || host->h_proto != proto)
 101                         continue;
 102
 103                 if (nlm_match_host(host, clnt, sin)) {
 104                         if (hp != nlm_hosts + hash) {
 105                                 *hp = host->h_next;
 106                                 host->h_next = nlm_hosts[hash];
 107                                 nlm_hosts[hash] = host;
 108                         }
 109                         nlm_get_host(host);
 110                         up(&nlm_host_sema);
 111                         return host;
 112                 }
 113         }
 114
 115         /* special hack for nlmsvc_invalidate_client */
 116         if (sin == NULL)
 117                 goto nohost;
 118
 119         /* Ooops, no host found, create it */
 120         dprintk("lockd: creating host entry\n");
 121
 122         if (!(host = (struct nlm_host *) kmalloc(sizeof(*host), GFP_KERNEL)))
 123                 goto nohost;
 124         memset(host, 0, sizeof(*host));
 125
 126         addr = sin->sin_addr.s_addr;
 127         sprintf(host->h_name, "%d.%d.%d.%d",
 128                         (unsigned char) (ntohl(addr) >> 24),
 129                         (unsigned char) (ntohl(addr) >> 16),
 130                         (unsigned char) (ntohl(addr) >>  8),
 131                         (unsigned char) (ntohl(addr) >>  0));
 132
 133         host->h_addr       = *sin;
 134         host->h_addr.sin_port = 0;      /* ouch! */
 135         host->h_version    = version;
 136         host->h_proto      = proto;
 137         host->h_authflavor = RPC_AUTH_UNIX;
 138         host->h_rpcclnt    = NULL;
 139         init_MUTEX(&host->h_sema);
 140         host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 141         host->h_expires    = jiffies + NLM_HOST_EXPIRE;
 142         host->h_count      = 1;
 143         init_waitqueue_head(&host->h_gracewait);
 144         host->h_state      = 0;                 /* pseudo NSM state */
 145         host->h_nsmstate   = 0;                 /* real NSM state */
 146         host->h_exportent  = clnt;
 147
 148         host->h_next       = nlm_hosts[hash];
 149         nlm_hosts[hash]    = host;
 150
 151         if (++nrhosts > NLM_HOST_MAX)
 152                 next_gc = 0;
 153
 154 nohost:
 155         up(&nlm_host_sema);
 156         return host;
 157 }
 158
 159 /*
 160  * Create the NLM RPC client for an NLM peer
 161  */
 162 struct rpc_clnt *
 163 nlm_bind_host(struct nlm_host *host)
 164 {
 165         struct rpc_clnt *clnt;
 166         struct rpc_xprt *xprt;
 167
 168         dprintk("lockd: nlm_bind_host(%08x)\n",
 169                         (unsigned)ntohl(host->h_addr.sin_addr.s_addr));
 170
 171         /* Lock host handle */
 172         down(&host->h_sema);
 173
 174         /* If we've already created an RPC client, check whether
 175          * RPC rebind is required
 176          * Note: why keep rebinding if we're on a tcp connection?
 177          */
 178         if ((clnt = host->h_rpcclnt) != NULL) {
 179                 xprt = clnt->cl_xprt;
 180                 if (!xprt->stream && time_after_eq(jiffies, host->h_nextrebind)) {
 181                         clnt->cl_port = 0;
 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                 uid_t saved_fsuid = current->fsuid;
 188                 kernel_cap_t saved_cap = current->cap_effective;
 189
 190                 /* Create RPC socket as root user so we get a priv port */
 191                 current->fsuid = 0;
 192                 cap_raise (current->cap_effective, CAP_NET_BIND_SERVICE);
 193                 xprt = xprt_create_proto(host->h_proto, &host->h_addr, NULL);
 194                 current->fsuid = saved_fsuid;
 195                 current->cap_effective = saved_cap;
 196                 if (xprt == NULL)
 197                         goto forgetit;
 198
 199                 xprt_set_timeout(&xprt->timeout, 5, nlmsvc_timeout);
 200
 201                 clnt = rpc_create_client(xprt, host->h_name, &nlm_program,
 202                                         host->h_version, host->h_authflavor);
 203                 if (clnt == NULL) {
 204                         xprt_destroy(xprt);
 205                         goto forgetit;
 206                 }
 207                 clnt->cl_autobind = 1;  /* turn on pmap queries */
 208                 xprt->nocong = 1;       /* No congestion control for NLM */
 209
 210                 host->h_rpcclnt = clnt;
 211         }
 212
 213         up(&host->h_sema);
 214         return clnt;
 215
 216 forgetit:
 217         printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
 218         up(&host->h_sema);
 219         return NULL;
 220 }
 221
 222 /*
 223  * Force a portmap lookup of the remote lockd port
 224  */
 225 void
 226 nlm_rebind_host(struct nlm_host *host)
 227 {
 228         dprintk("lockd: rebind host %s\n", host->h_name);
 229         if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
 230                 host->h_rpcclnt->cl_port = 0;
 231                 host->h_nextrebind = jiffies + NLM_HOST_REBIND;
 232         }
 233 }
 234
 235 /*
 236  * Increment NLM host count
 237  */
 238 struct nlm_host * nlm_get_host(struct nlm_host *host)
 239 {
 240         if (host) {
 241                 dprintk("lockd: get host %s\n", host->h_name);
 242                 host->h_count ++;
 243                 host->h_expires = jiffies + NLM_HOST_EXPIRE;
 244         }
 245         return host;
 246 }
 247
 248 /*
 249  * Release NLM host after use
 250  */
 251 void nlm_release_host(struct nlm_host *host)
 252 {
 253         if (host && host->h_count) {
 254                 dprintk("lockd: release host %s\n", host->h_name);
 255                 host->h_count --;
 256         }
 257 }
 258
 259 /*
 260  * Shut down the hosts module.
 261  * Note that this routine is called only at server shutdown time.
 262  */
 263 void
 264 nlm_shutdown_hosts(void)
 265 {
 266         struct nlm_host *host;
 267         int             i;
 268
 269         dprintk("lockd: shutting down host module\n");
 270         down(&nlm_host_sema);
 271
 272         /* First, make all hosts eligible for gc */
 273         dprintk("lockd: nuking all hosts...\n");
 274         for (i = 0; i < NLM_HOST_NRHASH; i++) {
 275                 for (host = nlm_hosts[i]; host; host = host->h_next)
 276                         host->h_expires = 0;
 277         }
 278
 279         /* Then, perform a garbage collection pass */
 280         nlm_gc_hosts();
 281         up(&nlm_host_sema);
 282
 283         /* complain if any hosts are left */
 284         if (nrhosts) {
 285                 printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
 286                 dprintk("lockd: %d hosts left:\n", nrhosts);
 287                 for (i = 0; i < NLM_HOST_NRHASH; i++) {
 288                         for (host = nlm_hosts[i]; host; host = host->h_next) {
 289                                 dprintk("       %s (cnt %d use %d exp %ld)\n",
 290                                         host->h_name, host->h_count,
 291                                         host->h_inuse, host->h_expires);
 292                         }
 293                 }
 294         }
 295 }
 296
 297 /*
 298  * Garbage collect any unused NLM hosts.
 299  * This GC combines reference counting for async operations with
 300  * mark & sweep for resources held by remote clients.
 301  */
 302 static void
 303 nlm_gc_hosts(void)
 304 {
 305         struct nlm_host **q, *host;
 306         struct rpc_clnt *clnt;
 307         int             i;
 308
 309         dprintk("lockd: host garbage collection\n");
 310         for (i = 0; i < NLM_HOST_NRHASH; i++) {
 311                 for (host = nlm_hosts[i]; host; host = host->h_next)
 312                         host->h_inuse = 0;
 313         }
 314
 315         /* Mark all hosts that hold locks, blocks or shares */
 316         nlmsvc_mark_resources();
 317
 318         for (i = 0; i < NLM_HOST_NRHASH; i++) {
 319                 q = &nlm_hosts[i];
 320                 while ((host = *q) != NULL) {
 321                         if (host->h_count || host->h_inuse
 322                          || time_before(jiffies, host->h_expires)) {
 323                                 q = &host->h_next;
 324                                 continue;
 325                         }
 326                         dprintk("lockd: delete host %s\n", host->h_name);
 327                         *q = host->h_next;
 328                         if (host->h_monitored)
 329                                 nsm_unmonitor(host);
 330                         if ((clnt = host->h_rpcclnt) != NULL) {
 331                                 if (atomic_read(&clnt->cl_users)) {
 332                                         printk(KERN_WARNING
 333                                                 "lockd: active RPC handle\n");
 334                                         clnt->cl_dead = 1;
 335                                 } else {
 336                                         rpc_destroy_client(host->h_rpcclnt);
 337                                 }
 338                         }
 339                         kfree(host);
 340                         nrhosts--;
 341                 }
 342         }
 343
 344         next_gc = jiffies + NLM_HOST_COLLECT;
 345 }
 346