NSM: Move nsm_find() to fs/lockd/mon.c

The nsm_find() function sets up fresh nsm_handle entries.  This is
where we will store the "priv" cookie used to lookup nsm_handles during
reboot recovery.  The cookie will be constructed when nsm_find()
creates a new nsm_handle.

As much as possible, I would like to keep everything that handles a
"priv" cookie in fs/lockd/mon.c so that all the smarts are in one
source file.  That organization should make it pretty simple to see how
all this works.

To me, it makes more sense than the current arrangement to keep
nsm_find() with nsm_monitor() and nsm_unmonitor().

So, start reorganizing by moving nsm_find() into fs/lockd/mon.c.  The
nsm_release() function comes along too, since it shares the nsm_lock
global variable.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

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
  */