lockd: Clean up nlmsvc_lookup_host()

Clean up.

Change nlmsvc_lookup_host() to be purpose-built for server-side
nlm_host management.  This replaces the generic nlm_lookup_host()
helper function, just like on the client side.  The lookup logic is
specialized for server host lookups.

The server side cache also gets its own specialized equivalent of the
nlm_release_host() function.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 72 insertions, 19 deletions

diff --git a/fs/lockd/host.c b/fs/lockd/host.c
index c6942fb4bd0d..0250b0e4f5e9 100644
--- a/fs/lockd/host.c
+++ b/fs/lockd/host.c
@@ -383,6 +383,10 @@ struct nlm_host *nlmsvc_lookup_host(const struct svc_rqst *rqstp,
                                     const char *hostname,
                                     const size_t hostname_len)
 {
+        struct hlist_head *chain;
+        struct hlist_node *pos;
+        struct nlm_host *host = NULL;
+        struct nsm_handle *nsm = NULL;
         struct sockaddr_in sin = {
                 .sin_family     = AF_INET,
         };
@@ -404,6 +408,8 @@ struct nlm_host *nlmsvc_lookup_host(const struct svc_rqst *rqstp,
                         (int)hostname_len, hostname, rqstp->rq_vers,
                         (rqstp->rq_prot == IPPROTO_UDP ? "udp" : "tcp"));
 
+        mutex_lock(&nlm_host_mutex);
+
         switch (ni.sap->sa_family) {
         case AF_INET:
                 sin.sin_addr.s_addr = rqstp->rq_daddr.addr.s_addr;
@@ -414,10 +420,73 @@ struct nlm_host *nlmsvc_lookup_host(const struct svc_rqst *rqstp,
                 ni.src_sap = (struct sockaddr *)&sin6;
                 break;
         default:
-                return NULL;
+                dprintk("lockd: %s failed; unrecognized address family\n",
+                        __func__);
+                goto out;
         }
 
-        return nlm_lookup_host(&ni);
+        if (time_after_eq(jiffies, next_gc))
+                nlm_gc_hosts();
+
+        chain = &nlm_hosts[nlm_hash_address(ni.sap)];
+        hlist_for_each_entry(host, pos, chain, h_hash) {
+                if (!rpc_cmp_addr(nlm_addr(host), ni.sap))
+                        continue;
+
+                /* Same address. Share an NSM handle if we already have one */
+                if (nsm == NULL)
+                        nsm = host->h_nsmhandle;
+
+                if (host->h_proto != ni.protocol)
+                        continue;
+                if (host->h_version != ni.version)
+                        continue;
+                if (!rpc_cmp_addr(nlm_srcaddr(host), ni.src_sap))
+                        continue;
+
+                /* Move to head of hash chain. */
+                hlist_del(&host->h_hash);
+                hlist_add_head(&host->h_hash, chain);
+
+                nlm_get_host(host);
+                dprintk("lockd: %s found host %s (%s)\n",
+                        __func__, host->h_name, host->h_addrbuf);
+                goto out;
+        }
+
+        host = nlm_alloc_host(&ni, nsm);
+        if (unlikely(host == NULL))
+                goto out;
+
+        memcpy(nlm_srcaddr(host), ni.src_sap, ni.src_len);
+        host->h_srcaddrlen = ni.src_len;
+        hlist_add_head(&host->h_hash, chain);
+        nrhosts++;
+
+        dprintk("lockd: %s created host %s (%s)\n",
+                __func__, host->h_name, host->h_addrbuf);
+
+out:
+        mutex_unlock(&nlm_host_mutex);
+        return host;
+}
+
+/**
+ * nlmsvc_release_host - release server nlm_host
+ * @host: nlm_host to release
+ *
+ * Host is destroyed later in nlm_gc_host().
+ */
+void nlmsvc_release_host(struct nlm_host *host)
+{
+        if (host == NULL)
+                return;
+
+        dprintk("lockd: release server host %s\n", host->h_name);
+
+        BUG_ON(atomic_read(&host->h_count) < 0);
+        BUG_ON(!host->h_server);
+        atomic_dec(&host->h_count);
 }
 
 /*
@@ -517,22 +586,6 @@ struct nlm_host * nlm_get_host(struct nlm_host *host)
         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);
-                BUG_ON(atomic_read(&host->h_count) < 0);
-                if (atomic_dec_and_test(&host->h_count)) {
-                        BUG_ON(!list_empty(&host->h_lockowners));
-                        BUG_ON(!list_empty(&host->h_granted));
-                        BUG_ON(!list_empty(&host->h_reclaim));
-                }
-        }
-}
-
 static struct nlm_host *next_host_state(struct hlist_head *cache,
                                         struct nsm_handle *nsm,
                                         const struct nlm_reboot *info)
@@ -581,7 +634,7 @@ void nlm_host_rebooted(const struct nlm_reboot *info)
          */
         while ((host = next_host_state(nlm_hosts, nsm, info)) != NULL) {
                 nlmsvc_free_host_resources(host);
-                nlm_release_host(host);
+                nlmsvc_release_host(host);
         }
         while ((host = next_host_state(nlm_client_hosts, nsm, info)) != NULL) {
                 nlmclnt_recovery(host);