1 files changed, 133 insertions, 0 deletions

diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
index 81e1cc14246f..8e68e799293c 100644
--- a/fs/lockd/mon.c
+++ b/fs/lockd/mon.c
@@ -47,12 +47,51 @@ struct nsm_res {
 static struct rpc_clnt *        nsm_create(void);
 
 static struct rpc_program       nsm_program;
+static                          LIST_HEAD(nsm_handles);
+static                          DEFINE_SPINLOCK(nsm_lock);
 
 /*
  * Local NSM state
  */
 int                             nsm_local_state;
 
+static void nsm_display_ipv4_address(const struct sockaddr *sap, char *buf,
+                                     const size_t len)
+{
+        const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
+        snprintf(buf, len, "%pI4", &sin->sin_addr.s_addr);
+}
+
+static void nsm_display_ipv6_address(const struct sockaddr *sap, char *buf,
+                                     const size_t len)
+{
+        const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
+
+        if (ipv6_addr_v4mapped(&sin6->sin6_addr))
+                snprintf(buf, len, "%pI4", &sin6->sin6_addr.s6_addr32[3]);
+        else if (sin6->sin6_scope_id != 0)
+                snprintf(buf, len, "%pI6%%%u", &sin6->sin6_addr,
+                                sin6->sin6_scope_id);
+        else
+                snprintf(buf, len, "%pI6", &sin6->sin6_addr);
+}
+
+static void nsm_display_address(const struct sockaddr *sap,
+                                char *buf, const size_t len)
+{
+        switch (sap->sa_family) {
+        case AF_INET:
+                nsm_display_ipv4_address(sap, buf, len);
+                break;
+        case AF_INET6:
+                nsm_display_ipv6_address(sap, buf, len);
+                break;
+        default:
+                snprintf(buf, len, "unsupported address family");
+                break;
+        }
+}
+
 /*
  * Common procedure for NSMPROC_MON/NSMPROC_UNMON calls
  */
@@ -162,6 +201,100 @@ void nsm_unmonitor(const struct nlm_host *host)
         }
 }
 
+/**
+ * nsm_find - Find or create a cached nsm_handle
+ * @sap: pointer to socket address of handle to find
+ * @salen: length of socket address
+ * @hostname: pointer to C string containing hostname to find
+ * @hostname_len: length of C string
+ * @create: one means create new handle if not found in cache
+ *
+ * Behavior is modulated by the global nsm_use_hostnames variable
+ * and by the @create argument.
+ *
+ * Returns a cached nsm_handle after bumping its ref count, or if
+ * @create is set, returns a fresh nsm_handle if a handle that
+ * matches @sap and/or @hostname cannot be found in the handle cache.
+ * Returns NULL if an error occurs.
+ */
+struct nsm_handle *nsm_find(const struct sockaddr *sap, const size_t salen,
+                            const char *hostname, const size_t hostname_len,
+                            const int create)
+{
+        struct nsm_handle *nsm = NULL;
+        struct nsm_handle *pos;
+
+        if (!sap)
+                return NULL;
+
+        if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
+                if (printk_ratelimit()) {
+                        printk(KERN_WARNING "Invalid hostname \"%.*s\" "
+                                            "in NFS lock request\n",
+                                (int)hostname_len, hostname);
+                }
+                return NULL;
+        }
+
+retry:
+        spin_lock(&nsm_lock);
+        list_for_each_entry(pos, &nsm_handles, sm_link) {
+
+                if (hostname && nsm_use_hostnames) {
+                        if (strlen(pos->sm_name) != hostname_len
+                         || memcmp(pos->sm_name, hostname, hostname_len))
+                                continue;
+                } else if (!nlm_cmp_addr(nsm_addr(pos), sap))
+                        continue;
+                atomic_inc(&pos->sm_count);
+                kfree(nsm);
+                nsm = pos;
+                goto found;
+        }
+        if (nsm) {
+                list_add(&nsm->sm_link, &nsm_handles);
+                goto found;
+        }
+        spin_unlock(&nsm_lock);
+
+        if (!create)
+                return NULL;
+
+        nsm = kzalloc(sizeof(*nsm) + hostname_len + 1, GFP_KERNEL);
+        if (nsm == NULL)
+                return NULL;
+
+        memcpy(nsm_addr(nsm), sap, salen);
+        nsm->sm_addrlen = salen;
+        nsm->sm_name = (char *) (nsm + 1);
+        memcpy(nsm->sm_name, hostname, hostname_len);
+        nsm->sm_name[hostname_len] = '\0';
+        nsm_display_address((struct sockaddr *)&nsm->sm_addr,
+                                nsm->sm_addrbuf, sizeof(nsm->sm_addrbuf));
+        atomic_set(&nsm->sm_count, 1);
+        goto retry;
+
+found:
+        spin_unlock(&nsm_lock);
+        return nsm;
+}
+
+/**
+ * nsm_release - Release an NSM handle
+ * @nsm: pointer to handle to be released
+ *
+ */
+void nsm_release(struct nsm_handle *nsm)
+{
+        if (!nsm)
+                return;
+        if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
+                list_del(&nsm->sm_link);
+                spin_unlock(&nsm_lock);
+                kfree(nsm);
+        }
+}
+
 /*
  * Create NSM client for the local host
  */