1 files changed, 346 insertions, 0 deletions

diff --git a/fs/lockd/host.c b/fs/lockd/host.c
new file mode 100644
index 00000000000..52707c5ad6e
--- /dev/null
+++ b/fs/lockd/host.c
@@ -0,0 +1,346 @@
+/*
+ * linux/fs/lockd/host.c
+ *
+ * Management for NLM peer hosts. The nlm_host struct is shared
+ * between client and server implementation. The only reason to
+ * do so is to reduce code bloat.
+ *
+ * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
+ */
+
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/in.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/svc.h>
+#include <linux/lockd/lockd.h>
+#include <linux/lockd/sm_inter.h>
+
+
+#define NLMDBG_FACILITY		NLMDBG_HOSTCACHE
+#define NLM_HOST_MAX		64
+#define NLM_HOST_NRHASH		32
+#define NLM_ADDRHASH(addr)	(ntohl(addr) & (NLM_HOST_NRHASH-1))
+#define NLM_HOST_REBIND		(60 * HZ)
+#define NLM_HOST_EXPIRE		((nrhosts > NLM_HOST_MAX)? 300 * HZ : 120 * HZ)
+#define NLM_HOST_COLLECT	((nrhosts > NLM_HOST_MAX)? 120 * HZ :  60 * HZ)
+#define NLM_HOST_ADDR(sv)	(&(sv)->s_nlmclnt->cl_xprt->addr)
+
+static struct nlm_host *	nlm_hosts[NLM_HOST_NRHASH];
+static unsigned long		next_gc;
+static int			nrhosts;
+static DECLARE_MUTEX(nlm_host_sema);
+
+
+static void			nlm_gc_hosts(void);
+
+/*
+ * Find an NLM server handle in the cache. If there is none, create it.
+ */
+struct nlm_host *
+nlmclnt_lookup_host(struct sockaddr_in *sin, int proto, int version)
+{
+	return nlm_lookup_host(0, sin, proto, version);
+}
+
+/*
+ * Find an NLM client handle in the cache. If there is none, create it.
+ */
+struct nlm_host *
+nlmsvc_lookup_host(struct svc_rqst *rqstp)
+{
+	return nlm_lookup_host(1, &rqstp->rq_addr,
+			       rqstp->rq_prot, rqstp->rq_vers);
+}
+
+/*
+ * Common host lookup routine for server & client
+ */
+struct nlm_host *
+nlm_lookup_host(int server, struct sockaddr_in *sin,
+					int proto, int version)
+{
+	struct nlm_host	*host, **hp;
+	u32		addr;
+	int		hash;
+
+	dprintk("lockd: nlm_lookup_host(%08x, p=%d, v=%d)\n",
+			(unsigned)(sin? ntohl(sin->sin_addr.s_addr) : 0), proto, version);
+
+	hash = NLM_ADDRHASH(sin->sin_addr.s_addr);
+
+	/* Lock hash table */
+	down(&nlm_host_sema);
+
+	if (time_after_eq(jiffies, next_gc))
+		nlm_gc_hosts();
+
+	for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) {
+		if (host->h_proto != proto)
+			continue;
+		if (host->h_version != version)
+			continue;
+		if (host->h_server != server)
+			continue;
+
+		if (nlm_cmp_addr(&host->h_addr, sin)) {
+			if (hp != nlm_hosts + hash) {
+				*hp = host->h_next;
+				host->h_next = nlm_hosts[hash];
+				nlm_hosts[hash] = host;
+			}
+			nlm_get_host(host);
+			up(&nlm_host_sema);
+			return host;
+		}
+	}
+
+	/* Ooops, no host found, create it */
+	dprintk("lockd: creating host entry\n");
+
+	if (!(host = (struct nlm_host *) kmalloc(sizeof(*host), GFP_KERNEL)))
+		goto nohost;
+	memset(host, 0, sizeof(*host));
+
+	addr = sin->sin_addr.s_addr;
+	sprintf(host->h_name, "%u.%u.%u.%u", NIPQUAD(addr));
+
+	host->h_addr       = *sin;
+	host->h_addr.sin_port = 0;	/* ouch! */
+	host->h_version    = version;
+	host->h_proto      = proto;
+	host->h_rpcclnt    = NULL;
+	init_MUTEX(&host->h_sema);
+	host->h_nextrebind = jiffies + NLM_HOST_REBIND;
+	host->h_expires    = jiffies + NLM_HOST_EXPIRE;
+	atomic_set(&host->h_count, 1);
+	init_waitqueue_head(&host->h_gracewait);
+	host->h_state      = 0;			/* pseudo NSM state */
+	host->h_nsmstate   = 0;			/* real NSM state */
+	host->h_server	   = server;
+	host->h_next       = nlm_hosts[hash];
+	nlm_hosts[hash]    = host;
+	INIT_LIST_HEAD(&host->h_lockowners);
+	spin_lock_init(&host->h_lock);
+
+	if (++nrhosts > NLM_HOST_MAX)
+		next_gc = 0;
+
+nohost:
+	up(&nlm_host_sema);
+	return host;
+}
+
+struct nlm_host *
+nlm_find_client(void)
+{
+	/* find a nlm_host for a client for which h_killed == 0.
+	 * and return it
+	 */
+	int hash;
+	down(&nlm_host_sema);
+	for (hash = 0 ; hash < NLM_HOST_NRHASH; hash++) {
+		struct nlm_host *host, **hp;
+		for (hp = &nlm_hosts[hash]; (host = *hp) != 0; hp = &host->h_next) {
+			if (host->h_server &&
+			    host->h_killed == 0) {
+				nlm_get_host(host);
+				up(&nlm_host_sema);
+				return host;
+			}
+		}
+	}
+	up(&nlm_host_sema);
+	return NULL;
+}
+
+				
+/*
+ * Create the NLM RPC client for an NLM peer
+ */
+struct rpc_clnt *
+nlm_bind_host(struct nlm_host *host)
+{
+	struct rpc_clnt	*clnt;
+	struct rpc_xprt	*xprt;
+
+	dprintk("lockd: nlm_bind_host(%08x)\n",
+			(unsigned)ntohl(host->h_addr.sin_addr.s_addr));
+
+	/* Lock host handle */
+	down(&host->h_sema);
+
+	/* If we've already created an RPC client, check whether
+	 * RPC rebind is required
+	 * Note: why keep rebinding if we're on a tcp connection?
+	 */
+	if ((clnt = host->h_rpcclnt) != NULL) {
+		xprt = clnt->cl_xprt;
+		if (!xprt->stream && time_after_eq(jiffies, host->h_nextrebind)) {
+			clnt->cl_port = 0;
+			host->h_nextrebind = jiffies + NLM_HOST_REBIND;
+			dprintk("lockd: next rebind in %ld jiffies\n",
+					host->h_nextrebind - jiffies);
+		}
+	} else {
+		xprt = xprt_create_proto(host->h_proto, &host->h_addr, NULL);
+		if (IS_ERR(xprt))
+			goto forgetit;
+
+		xprt_set_timeout(&xprt->timeout, 5, nlmsvc_timeout);
+
+		/* Existing NLM servers accept AUTH_UNIX only */
+		clnt = rpc_create_client(xprt, host->h_name, &nlm_program,
+					host->h_version, RPC_AUTH_UNIX);
+		if (IS_ERR(clnt)) {
+			xprt_destroy(xprt);
+			goto forgetit;
+		}
+		clnt->cl_autobind = 1;	/* turn on pmap queries */
+		xprt->nocong = 1;	/* No congestion control for NLM */
+		xprt->resvport = 1;	/* NLM requires a reserved port */
+
+		host->h_rpcclnt = clnt;
+	}
+
+	up(&host->h_sema);
+	return clnt;
+
+forgetit:
+	printk("lockd: couldn't create RPC handle for %s\n", host->h_name);
+	up(&host->h_sema);
+	return NULL;
+}
+
+/*
+ * Force a portmap lookup of the remote lockd port
+ */
+void
+nlm_rebind_host(struct nlm_host *host)
+{
+	dprintk("lockd: rebind host %s\n", host->h_name);
+	if (host->h_rpcclnt && time_after_eq(jiffies, host->h_nextrebind)) {
+		host->h_rpcclnt->cl_port = 0;
+		host->h_nextrebind = jiffies + NLM_HOST_REBIND;
+	}
+}
+
+/*
+ * Increment NLM host count
+ */
+struct nlm_host * nlm_get_host(struct nlm_host *host)
+{
+	if (host) {
+		dprintk("lockd: get host %s\n", host->h_name);
+		atomic_inc(&host->h_count);
+		host->h_expires = jiffies + NLM_HOST_EXPIRE;
+	}
+	return host;
+}
+
+/*
+ * Release NLM host after use
+ */
+void nlm_release_host(struct nlm_host *host)
+{
+	if (host != NULL) {
+		dprintk("lockd: release host %s\n", host->h_name);
+		atomic_dec(&host->h_count);
+		BUG_ON(atomic_read(&host->h_count) < 0);
+	}
+}
+
+/*
+ * Shut down the hosts module.
+ * Note that this routine is called only at server shutdown time.
+ */
+void
+nlm_shutdown_hosts(void)
+{
+	struct nlm_host	*host;
+	int		i;
+
+	dprintk("lockd: shutting down host module\n");
+	down(&nlm_host_sema);
+
+	/* First, make all hosts eligible for gc */
+	dprintk("lockd: nuking all hosts...\n");
+	for (i = 0; i < NLM_HOST_NRHASH; i++) {
+		for (host = nlm_hosts[i]; host; host = host->h_next)
+			host->h_expires = jiffies - 1;
+	}
+
+	/* Then, perform a garbage collection pass */
+	nlm_gc_hosts();
+	up(&nlm_host_sema);
+
+	/* complain if any hosts are left */
+	if (nrhosts) {
+		printk(KERN_WARNING "lockd: couldn't shutdown host module!\n");
+		dprintk("lockd: %d hosts left:\n", nrhosts);
+		for (i = 0; i < NLM_HOST_NRHASH; i++) {
+			for (host = nlm_hosts[i]; host; host = host->h_next) {
+				dprintk("       %s (cnt %d use %d exp %ld)\n",
+					host->h_name, atomic_read(&host->h_count),
+					host->h_inuse, host->h_expires);
+			}
+		}
+	}
+}
+
+/*
+ * Garbage collect any unused NLM hosts.
+ * This GC combines reference counting for async operations with
+ * mark & sweep for resources held by remote clients.
+ */
+static void
+nlm_gc_hosts(void)
+{
+	struct nlm_host	**q, *host;
+	struct rpc_clnt	*clnt;
+	int		i;
+
+	dprintk("lockd: host garbage collection\n");
+	for (i = 0; i < NLM_HOST_NRHASH; i++) {
+		for (host = nlm_hosts[i]; host; host = host->h_next)
+			host->h_inuse = 0;
+	}
+
+	/* Mark all hosts that hold locks, blocks or shares */
+	nlmsvc_mark_resources();
+
+	for (i = 0; i < NLM_HOST_NRHASH; i++) {
+		q = &nlm_hosts[i];
+		while ((host = *q) != NULL) {
+			if (atomic_read(&host->h_count) || host->h_inuse
+			 || time_before(jiffies, host->h_expires)) {
+				dprintk("nlm_gc_hosts skipping %s (cnt %d use %d exp %ld)\n",
+					host->h_name, atomic_read(&host->h_count),
+					host->h_inuse, host->h_expires);
+				q = &host->h_next;
+				continue;
+			}
+			dprintk("lockd: delete host %s\n", host->h_name);
+			*q = host->h_next;
+			/* Don't unmonitor hosts that have been invalidated */
+			if (host->h_monitored && !host->h_killed)
+				nsm_unmonitor(host);
+			if ((clnt = host->h_rpcclnt) != NULL) {
+				if (atomic_read(&clnt->cl_users)) {
+					printk(KERN_WARNING
+						"lockd: active RPC handle\n");
+					clnt->cl_dead = 1;
+				} else {
+					rpc_destroy_client(host->h_rpcclnt);
+				}
+			}
+			BUG_ON(!list_empty(&host->h_lockowners));
+			kfree(host);
+			nrhosts--;
+		}
+	}
+
+	next_gc = jiffies + NLM_HOST_COLLECT;
+}
+